The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.T...The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes.Building on the anatomical characteristics of bone and interfacial tissues,this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues,specifically focusing on methods used to construct compositional and structural gradients within the scaffolds.The latest applications of gradient scaffolds for the regeneration of bone,osteochondral,and tendon-to-bone interfaces are presented.Furthermore,the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed,as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.展开更多
Biomedical metals are widely used as implant materials in the human or animal body to repair organs and restore function, such as heart valves, meninges, peritoneum and artificial organs.Alloying element affects the m...Biomedical metals are widely used as implant materials in the human or animal body to repair organs and restore function, such as heart valves, meninges, peritoneum and artificial organs.Alloying element affects the microstructure, mechanical property, corrosion resistance and wear resistance, but also influences the antibacterial and biological activity.Recently, antibacterial metal alloys have shown great potential as a new kind of biomedical materials, in which Cu has been widely used as antibacterial agent element.In addition, biodegradable metal alloys, including magnesium alloy and zinc alloy, also have attracted much attention worldwide.Cu was also used as alloying element to adjust the degradation rate.Thus, the role of Cu in the alloy design will be very important for the development of new alloy.In this paper, we summarized the recent research results on the Cu-containing metal alloy for biomedical application and hoped that this review would give more suggestions for the further development of biomedical metal alloy.展开更多
It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of ...It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of life science after cellular and molecular bioscience.Nevertheless,despite decades of rapid de-velopment,tissue-engineered biomaterials have not been widely used clinically.Biomaterials constructed by physical and chemical methods have lots of difficulty in precisely mimicking the macroscopic and mi-croscopic structures of human tissues.The ultimate way to build organoid tissue for regeneration is to enable the cells to take the initiative and build suitable functions.Based on the thoughts of tissue engi-neering,organoid technology holds great potential as a research tool for a wide range of fields,including developmental biology,disease pathology,cell biology,precision medicine,and drug toxicity and efficacy testing.This technology also holds tremendous potential for regenerative medicine,as organoids present the possibility for autologous and allogeneic cell therapy through the replacement of damaged or dis-eased tissues with organoid-propagated tissue or stem cell populations.In this review work,we briefly outlook the development history of organoid technology,summarize the current bottlenecks and the un-derlying reasons,and propose the unified term“function-oriented design in tissue engineering”,a new topic that may provide a solution to overcome these bottlenecks.展开更多
Effective treatment of intervertebral disc degeneration with biomaterials remains a challenge,owing to the difficulty in simultaneously overcoming oxidative stress and its associated cascades in the nucleus pulposus m...Effective treatment of intervertebral disc degeneration with biomaterials remains a challenge,owing to the difficulty in simultaneously overcoming oxidative stress and its associated cascades in the nucleus pulposus microenvironment,which includes cellular senescence,apoptosis,inflammation,and extracellular matrix(ECM)degradation.To address these issues,a multifunctional hydrogel(HG-QNT)loaded with transforming growth factorβ1(TGFβ1)and quercetin-based nanoparticles(QUNPs)is developed through borate ester bonding and Schiffbase reaction-induced crosslinking.Specifically,QUNPs fabricated via coordination and hydrophobic interactions endow the hydrogel with extraordinary antioxidative properties.Benefiting from the multi-dynamic crosslinking,the hydrogel achieves self-healing,mechanical stability,and pH-responsive release of QUNPs and TGFβ1.The HG-QNT hydrogel is demonstrated to enhance the proliferation of encapsulated nucleus pulposus cells,thereby providing an ideal platform for cell transplantation.The cooperative antioxidation of QUNPs and the hydrogel carrier renders HG-QNT effective in mitigating oxidative stress,resulting in the suppression of cellular senescence,mitochondrial dysfunction,apoptosis,excessive inflammation,and abnormal catabolism.Afterwards,TGFβ1 and QUNPs act in synergy with the hydrogel to restore the anabolic/catabolic balance by enhancing ECM synthesis.Overall,the strategy orchestrating multiple modulation by HG-QNT hydrogel shows great potential for application in intervertebral disc regeneration.展开更多
The poor mechanical properties of pure zinc(Zn)restrain its applications in orthopedics,which requires high loading capacity.Alloying with lithium(Li)element can enhance strength,however,the work-hardening rate is imp...The poor mechanical properties of pure zinc(Zn)restrain its applications in orthopedics,which requires high loading capacity.Alloying with lithium(Li)element can enhance strength,however,the work-hardening rate is impaired with increased Li content.Here,introducing scandium(Sc)into a low Li-containing Zn-0.1Li alloy could effectively refine its microstructure,reducing the average grain size from 10 to 4μm.The refinement in microstructure led to a significant improvement in tensile strength,im-proving from 257 MPa of Zn-0.1Li to 341 MPa of Zn-0.1Li-0.1Sc,meanwhile,the work-hardening rate remained positive during the whole plastic deformation stage.The addition of Sc-impaired elongation is due to numerous microcracks formed at the Zn/ScZn_(12)interfaces,as well as in the large-sized ScZn_(12)particles.Corrosion tests revealed an accelerated corrosion rate due to the galvanic effect between the Zn matrix and ScZn_(12)phase.Even so,the Zn-0.1Li-1.0Sc alloy still exhibited superior biocompatibility with rat/mouse mesenchymal stem cells and close osteogenesis capacity to the original Zn-0.1Li alloy.These findings demonstrated that the addition of Sc in low Li-containing alloys could improve mechanical strength without sacrificing the work-hardening rate and biocompatibility.展开更多
The development of highly efficient and multifunctional nanozymes holds promise for addressing the challenges posed by drugresistant bacteria.Here,copper single-atom-loaded MoS_(2) nanozymes(CuSAs/MoS_(2))were develop...The development of highly efficient and multifunctional nanozymes holds promise for addressing the challenges posed by drugresistant bacteria.Here,copper single-atom-loaded MoS_(2) nanozymes(CuSAs/MoS_(2))were developed to effectively combat drug-resistant bacteria by synergistically integrating the triple strategies of oxidative damage,cuproptosis-like death and disruption of cell wall synthesis.Density functional theory revealed that each Cu center coordinated with three sulfur ligands,enhancing the adsorption of H_(2)O_(2),which reduced the activation energy of the key step by 17%,thereby improving peroxidase-like(PODlike)activity.The generation of reactive oxygen species in combination with CuSAs/MoS_(2) glutathione peroxidase-like(GSH-Px-like)for glutathione scavenging resulted in an imbalance in redox homeostasis within bacteria.CuSAs/MoS_(2),which act as nanopioneers,drive oxidative stress to initiate the process of cuproptosis-like death,leading to abnormal aggregation of lipoylated proteins and inactivation of iron-sulfur cluster proteins.Moreover,CuSAs/MoS_(2) inhibited the biosynthesis of the peptidoglycan synthesis precursors D-glutamate and m-diaminopimelic acid and disrupted the peptidoglycan cross-linking process mediated by penicillin-binding proteins,effectively blocking the compensatory cell wall remodeling pathway ofβ-lactam-resistant bacteria.Overall,CuSAs/MoS_(2) with multiple functions can not only efficiently kill bacteria but also decelerate the development of bacterial resistance to combat drug-resistant bacterial infections.展开更多
β-type titanium alloys have attracted much attention as implant materials because of their low elastic modulus and high strength,which is closer to human bones and can avoid the problem of stress fielding and extend ...β-type titanium alloys have attracted much attention as implant materials because of their low elastic modulus and high strength,which is closer to human bones and can avoid the problem of stress fielding and extend the lifetime of prosthetics.However,other issues,such as the infection or inflammation postimplantation,still trouble the titanium alloy's clinical application.In this paper,we developed a novel nearβ-titanium alloy(Ti-13Nb-13Zr-13Ag,TNZA)with low elastic modulus and strong antibacterial ability by the addition of Ag element followed by proper microstructure controlling,which could reduce the stress shielding and bacterial infections simultaneously.The microstructure,mechanical properties,corrosion resistance,antibacterial properties and cell toxicity were studied using SEM,electrochemical testing,mechanical test and cell tests.The results have demonstrated that TNZA alloy exhibited an elastic modulus of 75-87 GPa and a strong antibacterial ability(up to 98%reduction)and good biocompatibility.Moreover,it was also shown that this alloy's corrosion resistance was better than that of Ti-13Nb-13Zr.All the results suggested that Ti-13Nb-13Zr-13Ag might be a competitive biomedical titanium alloy.展开更多
Ti–3Cu alloy has shown low melting point and strong antibacterial properties against S.aureus and E.coli and thus has potential application as dental materials and orthopedic application.In this paper, the corrosion ...Ti–3Cu alloy has shown low melting point and strong antibacterial properties against S.aureus and E.coli and thus has potential application as dental materials and orthopedic application.In this paper, the corrosion properties of Ti–3Cu alloy in five kinds of simulated solutions were investigated in comparison with cp-Ti(commercially pure titanium) by electrochemical technology and immersion experiment.Electrochemical results have demonstrated that Ti–3Cu alloy exhibited much nobler corrosion potential, lower corrosion current density and high corrosion resistance than cp-Ti in all solutions, especially in saliva-pH6.8+0.2 F and saliva-pH3.5, indicating that Ti–3Cu alloy has much better anticorrosion properties than cpTi.Immersion results have shown that Ti ion and Cu ion were released from Ti–3Cu, especially in saliva-pH6.8+0.2 F and saliva-pH3.5 solutions.Both electrochemical data and immersion results have indicated that high corrosion rate and high metal ion release rate were detected in F ion-containing solution and low-pH solution, displaying that F^- and low pH had much strong aggressive attack to cp-Ti and Ti–3Cu alloy.The corroded surface morphology was observed by scanning electron microscopy(SEM), and the roughness was tested in the end.The good corrosion resistance of antibacterial Ti–3Cu alloy suggests its great potential as a long-term biomedical application.展开更多
The daily life of people in the intelligent age is inseparable from electronic device,and a number of bacteria on touch screens are increasingly threatening the health of users.Herein,a photocatalytic TiO_(2)/Ag thin ...The daily life of people in the intelligent age is inseparable from electronic device,and a number of bacteria on touch screens are increasingly threatening the health of users.Herein,a photocatalytic TiO_(2)/Ag thin film was synthesized on a glass by atomic layer deposition and subsequent in situ reduction.Ultraviolet-visible(UV-Vis)spectra showed that this film can harvest the simulated solar light more efficiently than that of pristine TiO_(2).The antibacterial tests in vitro showed that the antibacterial efficiency of the TiO_(2)/Ag film against S.aureus and E.coli was 98.2%and 98.6%,under visible light irradiation for 5 min.The underlying mechanism was that the in-situ reduction of Ag on the surface of TiO_(2)reduced the bandgap of TiO_(2)from 3.44 to 2.61 eV due to the formation of Schottky heterojunction at the interface between TiO_(2)and Ag.Thus,TiO_(2)/Ag can generate more reactive oxygen species for bacterial inactivation on the surface of electronic screens.More importantly,the TiO_(2)/Ag film had great biocompatibility with/without light irradiation.The platform not only provides a more convenient choice for the traditional antibacterial mode but also has limitless possibilities for application in the field of billions of touch screens.展开更多
In this work,the one-step stereochemical antimicrobial finishing of cotton textiles(CT)was achieved by the oxidative copolymerization of a dopamine-menthol derivative(DAM)and dopamine(DA).The obtained DAM-modified CT(...In this work,the one-step stereochemical antimicrobial finishing of cotton textiles(CT)was achieved by the oxidative copolymerization of a dopamine-menthol derivative(DAM)and dopamine(DA).The obtained DAM-modified CT(P(DAM-co-DA)-CT)exhibited broad-spectrum microbial anti-adhesion properties against bacteria(E.coli and P.aeruginosa),including superbugs(MRSA and VREF),and fungi(A.niger,A.flavus,M.racemosus and P.chrysogenum).Because of its unique stereochemical antimicrobial mechanism,the obtained P(DAM-co-DA)-CT is a non-releasing antimicrobial material that causes no skin sensitization and exhibits good biocompatibility.The coating was also found to enhance the UVresistant and mechanical properties of the CT.Furthermore,it displayed durable washing fastness and antimicrobial properties after the endurance of 30 laundering cycles.The observed achievements provide a broader understanding of stereochemical antimicrobial surfaces and endow this method with wider applications.展开更多
In the past few decades,additive manufacturing(AM)has been developed and applied as a cost-effective and versatile technique for the fabrication of geometrically complex objects in the medical industry.In this review,...In the past few decades,additive manufacturing(AM)has been developed and applied as a cost-effective and versatile technique for the fabrication of geometrically complex objects in the medical industry.In this review,we discuss current advances of AM in medical applications for the generation of pharmaceuticals,medical implants,and medical devices.Oral and transdermal drugs can be fabricated by a variety of AM technologies.Different types of hard and soft clinical implants have also been realized by AM,with the goal of producing tissue-engineered constructs.In addition,medical devices used for diagnostics and treatment of various pathological conditions have been developed.The growing body of research on AM reveals its great potential in medical applications.The goal of this review is to highlight the usefulness and elucidate the current limitations of AM applications in the medical field.展开更多
Hydroxyapatite-graft-poly(D-lactide)(HA-g-PDLA)was synthesized by ring-opening polymerization with HA as initiator and stannous octanoate(Sn(Oct)2)as catalyst.Thermogravimetric analysis(TGA)and Fourier transform infra...Hydroxyapatite-graft-poly(D-lactide)(HA-g-PDLA)was synthesized by ring-opening polymerization with HA as initiator and stannous octanoate(Sn(Oct)2)as catalyst.Thermogravimetric analysis(TGA)and Fourier transform infrared spectroscopy(FUR)results indicate that PDLA chains are successfully grafted onto HA particles by covalent bond.Under two different processing temperatures(190 and 230℃),the effect of the grafted PDLA chains on the crystallization behavior of poly(L-lactide)/HA-g-PDLA(PLLA/HA-g-PDLA)composite was investigated in the current study,comparing to neat PLLA and its four composites(PLLA/HA,PLLA/HA-g-PLLA,PLLA/PDLA,and PLLA/HA/PDLA).The crystallization rate of PLLA/HA-g-PDLA composite is highly enhanced comparing to PLLA,PLLA/HA and PLLA/HA-g-PLLA composites in which there are no stereocomplex(SC)crystallites.In addition,when the processing temperature rises from 190℃ to 230℃,the acceleration of PLLA crystallization in PLLA/HA-g-PDLA composite is not influenced so much as other composites containing SC crystallites,such as PLLA/HA/PDLA or PLLA/PDLA.The differential scanning calorimetry(DSC)results demonstrate that even without SC crystallites,the crystallization of PLLA can still be accelerated a lot in this composite.This may be related to the interaction between the grafted PDLA chains and the amorphous PLLA chains in PLLA/HA-g-PDLA composite.The isothermal crystallization kinetics studies indicate that the nature of nucleation and crystal growth of PLLA/HAg-PDLA composite are more likely 3D crystalline growth with heterogeneous nucleation mode,which are different from PLLA or other composites.This investigation could shed new light on the application of PLLA/HA composites.展开更多
Antibacterial Ti-5Cu alloy is a promising substitute material for Ti-made cardiovascular implants,so its surface engineering is crucial to expediting clinical implementation.Given the antibacterial and cardiovas-cular...Antibacterial Ti-5Cu alloy is a promising substitute material for Ti-made cardiovascular implants,so its surface engineering is crucial to expediting clinical implementation.Given the antibacterial and cardiovas-cular biological benefits of Cu^(2+)and titanium-nitride-oxide(TiN x O y)coatings,a Cu_(2)O/CuO-TiN x O y coating with upregulated Cu^(2+)release was successfully deposited on Ti-5Cu alloy for the first time using oxygen and nitrogen plasma-based surface modification.The superhydrophilic and nanostructured Cu_(2)O/CuO-TiN x O y coating had a dense structure and was well bonded to the substrate,resulting in enhanced cor-rosion resistance,while CuO/Cu_(2)O in the coating released Cu^(2+)faster than Ti_(2)Cu phase in the matrix.More gratifying,the coating demonstrated perfect antibacterial properties(R>99.9%against S.aureus),owing primarily to direct contact sterilization of Cu_(2)O/CuO.The most encouraging phenomenon was that the coating dramatically accelerated HUVEC adhesion(1.4 times),proliferation(RGR:106%-116%),and particularly migration(RMR:158%-247%)compared with the control Ti.The coating extract also signifi-cantly stimulated in vitro angiogenesis capacity.The rapid endothelialization for Cu_(2)O/CuO-TiN x O y coating was attributed to the surface nanostructure and Cu^(2+)/NO_(2)−release,which upregulated the angiogenesis-related gene expression of HIF-1α,VEGF,and eNOS to increase VEGF secretion and NO production.All of the findings indicated that the Cu_(2)O/CuO-TiN x O y coating could enhance the corrosion resistance,an-tibacterial properties,and endothelialization potential of Ti-Cu alloy,displaying great clinical potential in cardiovascular applications.展开更多
Ti-Cu alloy has potential to be used in plastic surgery and dental implants due to its strong antibacterialproperties,high strength and good corrosion resistance.In this paper,Ti-5Cu was anodic-oxidized to enhance the...Ti-Cu alloy has potential to be used in plastic surgery and dental implants due to its strong antibacterialproperties,high strength and good corrosion resistance.In this paper,Ti-5Cu was anodic-oxidized to enhance the surface compatibility.The influence of the oxidation on the corrosion resistance,antibacterial properties and biological properties was investigated.X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)results showed that a double-layer oxide coating with dense inner layer and porous outside layer was formed on Ti-Cu sample.The oxide coating consisted mainly of TiO2,CuzO and small amount of CuO,improved the corrosion resistance of Ti-Cu alloy by one order of magnitude due to the formation of the dense oxide inner layer,but high Cu ion release was detected.The plate count results showed that the antibac-terial activity of Ti-Cu sample was improved to≥99%due to the comprehensive function of CuO and Cu_(2)O in the coating and Cu^(2+)release.Cell test results showed that thecoating exhibited good cell compatibility,the porous sur-face structure improved the adhesion of cells,and Cu ion release promoted the cell proliferation.展开更多
The synthesis and structure-property correlation of poly（N-（2-hydroxypropyl） methacrylamide） （PHPMA） conjugates with various architectures including random, block, branched or star-like structures and compositio...The synthesis and structure-property correlation of poly（N-（2-hydroxypropyl） methacrylamide） （PHPMA） conjugates with various architectures including random, block, branched or star-like structures and compositions have been thoroughly explored. However, related synthesis and structure-property data are still lacking for comb-like PHPMA. In this work, we report the synthesis of comb-like PHPMA copolymer-doxorubicin （DOX） conjugates with different backbone/side-chain lengths and location of drug moieties. Well-defined comb-like PHPMA-DOX conjugates are obtained via the combination of controlled radical polymerization and fractional precipitation techniques. The influences of structural factors on the biological properties such as cellular uptake, blood circulation and tumor accumulation have been investigated. Long blood circulation and efficient tumor accumulation can be achieved by proper control of the comb number, length and location of drug moieties. These facile comb-like structures possess great potentials in future theranostics for brachytherapy or surgical navigation.展开更多
It is highly desired to have bioactive surfaces for biomaterials and controllable interactions with cells.These functions were widely achieved by attaching functional peptides to the surface of biomaterials.It is well...It is highly desired to have bioactive surfaces for biomaterials and controllable interactions with cells.These functions were widely achieved by attaching functional peptides to the surface of biomaterials.It is well known that an antifouling layer can help reducing the nonspecific cell attachment.However,it is unclear how an antifouling PEG layer affects the function of peptides attached on material surface in controlling cell behavior.This highlight introduced the recent JACS paper from Prof.Liu and coworkers in addressing this question thoroughly.展开更多
Porous hybrid microspheres were fabricated by the synthesized calcium gluconate-g-poly（D,L-lactide） （CG-g- PDLLA） composites. These hybrid microspheres were treated with an alkaline solution for different period o...Porous hybrid microspheres were fabricated by the synthesized calcium gluconate-g-poly（D,L-lactide） （CG-g- PDLLA） composites. These hybrid microspheres were treated with an alkaline solution for different period of time to control the amount of generated carboxylate groups and remained CG on the surface. The microspheres were then incubated in a supersaturated simulated body fluid （1.5 SBF） solution for different time to investigate their biomimetic mineralization behavior. The depositions were found to have a fine cluster morphology, a similar crystal structure and chemical structure to natural hydroxyapatite, and a medium Ca/P of approximately 1.30. The effect of surface treating time on the structure and mineralization behavior of these microspheres has been discussed in detail. The results indicate that the nucleation and growth of apatite on the surface are influenced by the induced carboxylate groups and the remained CG. The hybrid CG-g- PDLLA microspheres have the potential as a novel alternative in bone tissue engineering.展开更多
Poly(styrene-6-isobutylene-6-styrene)triblock copolymer(SIBS),a kind of thermoplastic elastomer with biocompatibility and biostability containing fully saturated soft segments,could be synthesized via living cationic ...Poly(styrene-6-isobutylene-6-styrene)triblock copolymer(SIBS),a kind of thermoplastic elastomer with biocompatibility and biostability containing fully saturated soft segments,could be synthesized via living cationic copolymerization.A novel poly[(styrene-co-methylstyrene)-b-isobutylene-b-(styrene-co-methylstyrene)]-g-polytetrahydrofuran(M-SIBS-g-PTHF)block graft copolymer was prepared to increase the polarity and service temperature of SIBS by grafting polar PTHF segments onto SIBS.A series of the above block graft copolymers with average grafting numbers from 2 to 6 and molecular weights of PTHF branches ranging from 200 g·mol^(-1)to 4200 g·mol^(-1)were successfully synthesized via living cationic ring-opening polymerization of tetrahydrofuran(THF)coinitiated by AgCI04.The introduction of PTHF branches led to an obvious microphase separation due to thermodynamic incompatibility among the three kinds of segments of polyisobutylene(PIB),polystyrene(PS)and PTHF.Moreover,the microphase separation promotes the rearrangement of PTHF branches to form the nanocrystallization-locked physically cross-linked network after storage at room temperature for 2 months,leading to insolubility of the copolymers even in good solvents.The melting temperature and enthalpy of PTHF nanocrystallization locked in hard domains of M-SIBS-g5-PTHF-1.1k block graft copolymer increased remarkably up to 153℃and 117.0 J·g^(-1)by 23℃and 11.6 J·g^-1(respectively after storage for long time.Storage modulus(G′)is higher than loss modulus(G″)of M-SIBS-g-PTHF block graft copolymer at temperatures ranging from 100℃to 180℃,which is much higher than those of the SIBS triblock copolymer.To the best of our knowledge,this is the first example of high performance M-SIBS-g-PTHF block graft copolymers containing segments of PIB,PS and PTHF with nanocrystallization-locked architecture.展开更多
The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose(HPC)backbone and hydrophobic soft nonpolar polyisobutylene(PIB)branches have been successfully synthesized through nucleophili...The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose(HPC)backbone and hydrophobic soft nonpolar polyisobutylene(PIB)branches have been successfully synthesized through nucleophilic substitution reaction of living PIB chains carrying oxonium ions with the-OH groups along HPC backbone.The PIB branch length in the graft copolymers could be designed by living cationic polymerization and the grafting density could be adjusted by PIB+/-OH molar ratio.The living PIB chains carrying oxonium ion were prepared by transformation of allyl bromide end groups in the presence of AgCI0_(4) and silver nanoparticles(3.2±0.3 nm,0.7 wt%-1.8 wt%)generated in situ from AgBr.The phase-separation morphology was formed in the graft copolymers due to their incompatibility between backbone and branches.The hydrophilicity on the surface of graft copolymer films could be turned to hydrophobicity by increasing grafting density or/and length of PIB branches.The soft PIB segments in graft copolymers provided an unique surface wa self-assembly for ant卜protein adsorption against bovine serum albumin.A small amount of Ag nanoparticles in the copolymers contributed to good antibacterial activities against Staphylococcus aureus or Escherichia coli.展开更多
This work focuses on the interaction between polymeric micelles with different charged surfaces and cancer cells in order to study the influence of surface charge on the in vitro cellular uptake efficiency. The amphip...This work focuses on the interaction between polymeric micelles with different charged surfaces and cancer cells in order to study the influence of surface charge on the in vitro cellular uptake efficiency. The amphiphilic diblock copolymers poly（e-caprolaetone）-b-poly（ethylene oxide） （PCL-b-PEO） with different functional groups at the end of hydrophilic block were synthesized. The functional groups endue the micelles with different charges on the surfaces. The cellular uptake of micelles to T-24 cells （human bladder tumor cells）, HepG2 cells （human liver hepatocellular carcinoma cell line） and Hela cells （human epithelial cervical cancer cells） was studied by means of flow cytometer and confbcal laser scanning microscopy. The results indicate that the surface charges showed great influence on zeta potential of micelles at different pH values. The in vitro cellular uptake efficiency of micelles with different charged surfaces demonstrated different cellular uptake patterns to three kinds of cancer cells.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52473121,52403370 and 52221006)Fundamental Research Funds for the Central Universities(buctrc202020,buctrc202312).
文摘The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes.This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes.Building on the anatomical characteristics of bone and interfacial tissues,this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues,specifically focusing on methods used to construct compositional and structural gradients within the scaffolds.The latest applications of gradient scaffolds for the regeneration of bone,osteochondral,and tendon-to-bone interfaces are presented.Furthermore,the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed,as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.
基金financially supported by the National Natural Science Foundation of China (Nos.81071262 and 31470930)the Beijing Municipal Natural Science Foundation (No.7161001)
文摘Biomedical metals are widely used as implant materials in the human or animal body to repair organs and restore function, such as heart valves, meninges, peritoneum and artificial organs.Alloying element affects the microstructure, mechanical property, corrosion resistance and wear resistance, but also influences the antibacterial and biological activity.Recently, antibacterial metal alloys have shown great potential as a new kind of biomedical materials, in which Cu has been widely used as antibacterial agent element.In addition, biodegradable metal alloys, including magnesium alloy and zinc alloy, also have attracted much attention worldwide.Cu was also used as alloying element to adjust the degradation rate.Thus, the role of Cu in the alloy design will be very important for the development of new alloy.In this paper, we summarized the recent research results on the Cu-containing metal alloy for biomedical application and hoped that this review would give more suggestions for the further development of biomedical metal alloy.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.U22A20162,31900583,32071351,81772400,82102604,and 81960395)the Natural Science Foundation of Guangzhou City(No.201807010031)+5 种基金the Foundation of Shenzhen Committee for Science and Technology Innovation(Nos.JCYJ20190809142211354,and GJHZ20180929160004704)the Sanming Project of Medicine in Shenzhen(No.SZSM201911002)the Beijing Municipal Health Commission(Nos.BMHC-2021-6,BMHC-2019-9,BMHC-2018-4,and PXM2020_026275_000002)the AOCMF Translational approaches for bone constructs(No.AOCMF-21-04S)the Sun Yatsen University Clinical Research 5010 Program(No.2019009)the Academic Affairs Office of Sun Yat-sen University(Nos.202211583,and 202211589).
文摘It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of life science after cellular and molecular bioscience.Nevertheless,despite decades of rapid de-velopment,tissue-engineered biomaterials have not been widely used clinically.Biomaterials constructed by physical and chemical methods have lots of difficulty in precisely mimicking the macroscopic and mi-croscopic structures of human tissues.The ultimate way to build organoid tissue for regeneration is to enable the cells to take the initiative and build suitable functions.Based on the thoughts of tissue engi-neering,organoid technology holds great potential as a research tool for a wide range of fields,including developmental biology,disease pathology,cell biology,precision medicine,and drug toxicity and efficacy testing.This technology also holds tremendous potential for regenerative medicine,as organoids present the possibility for autologous and allogeneic cell therapy through the replacement of damaged or dis-eased tissues with organoid-propagated tissue or stem cell populations.In this review work,we briefly outlook the development history of organoid technology,summarize the current bottlenecks and the un-derlying reasons,and propose the unified term“function-oriented design in tissue engineering”,a new topic that may provide a solution to overcome these bottlenecks.
基金supported by the National Natural Science Foun-dation of China(Grant No.52073103,52272276,51873069,and 52373128)Beijing Municipal Health Commission(BMHC-2021-6,BJRITO-RDP-2024)Beijing Municipal Public Welfare Devel-opment and Reform Pilot Project for Medical Research Institutes(JYY2023-11,JYY2023-8).
文摘Effective treatment of intervertebral disc degeneration with biomaterials remains a challenge,owing to the difficulty in simultaneously overcoming oxidative stress and its associated cascades in the nucleus pulposus microenvironment,which includes cellular senescence,apoptosis,inflammation,and extracellular matrix(ECM)degradation.To address these issues,a multifunctional hydrogel(HG-QNT)loaded with transforming growth factorβ1(TGFβ1)and quercetin-based nanoparticles(QUNPs)is developed through borate ester bonding and Schiffbase reaction-induced crosslinking.Specifically,QUNPs fabricated via coordination and hydrophobic interactions endow the hydrogel with extraordinary antioxidative properties.Benefiting from the multi-dynamic crosslinking,the hydrogel achieves self-healing,mechanical stability,and pH-responsive release of QUNPs and TGFβ1.The HG-QNT hydrogel is demonstrated to enhance the proliferation of encapsulated nucleus pulposus cells,thereby providing an ideal platform for cell transplantation.The cooperative antioxidation of QUNPs and the hydrogel carrier renders HG-QNT effective in mitigating oxidative stress,resulting in the suppression of cellular senescence,mitochondrial dysfunction,apoptosis,excessive inflammation,and abnormal catabolism.Afterwards,TGFβ1 and QUNPs act in synergy with the hydrogel to restore the anabolic/catabolic balance by enhancing ECM synthesis.Overall,the strategy orchestrating multiple modulation by HG-QNT hydrogel shows great potential for application in intervertebral disc regeneration.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20121 and 52101283)the Suzhou Science and Technology Project(Grant No SJC2023005)+3 种基金the Science and Technology Planning Project of Guangzhou(Grant No 202102010008)the High-Level Hospital Construction Project(Grant No KJ012019520)the Beijing Mu-nicipal Health Commission(BMHC-2021-6,BJRITO-RDP-2024)the Beijing Municipal Public Welfare Development and Reform Pilot Project for Medical Research Institutes(Nos.JYY2023-11 and JYY2023-8).
文摘The poor mechanical properties of pure zinc(Zn)restrain its applications in orthopedics,which requires high loading capacity.Alloying with lithium(Li)element can enhance strength,however,the work-hardening rate is impaired with increased Li content.Here,introducing scandium(Sc)into a low Li-containing Zn-0.1Li alloy could effectively refine its microstructure,reducing the average grain size from 10 to 4μm.The refinement in microstructure led to a significant improvement in tensile strength,im-proving from 257 MPa of Zn-0.1Li to 341 MPa of Zn-0.1Li-0.1Sc,meanwhile,the work-hardening rate remained positive during the whole plastic deformation stage.The addition of Sc-impaired elongation is due to numerous microcracks formed at the Zn/ScZn_(12)interfaces,as well as in the large-sized ScZn_(12)particles.Corrosion tests revealed an accelerated corrosion rate due to the galvanic effect between the Zn matrix and ScZn_(12)phase.Even so,the Zn-0.1Li-1.0Sc alloy still exhibited superior biocompatibility with rat/mouse mesenchymal stem cells and close osteogenesis capacity to the original Zn-0.1Li alloy.These findings demonstrated that the addition of Sc in low Li-containing alloys could improve mechanical strength without sacrificing the work-hardening rate and biocompatibility.
基金supported by the National Natural Science Foundation of China(82372552)the Excellent Youth of Natural Science Research Projects in Anhui Province Universities(2023AH030060)+1 种基金Anhui Provincial Natural Science Foundation(2408085Y016)Anhui Province Excellent Research and Innovation Team Project(2024AH010013)。
文摘The development of highly efficient and multifunctional nanozymes holds promise for addressing the challenges posed by drugresistant bacteria.Here,copper single-atom-loaded MoS_(2) nanozymes(CuSAs/MoS_(2))were developed to effectively combat drug-resistant bacteria by synergistically integrating the triple strategies of oxidative damage,cuproptosis-like death and disruption of cell wall synthesis.Density functional theory revealed that each Cu center coordinated with three sulfur ligands,enhancing the adsorption of H_(2)O_(2),which reduced the activation energy of the key step by 17%,thereby improving peroxidase-like(PODlike)activity.The generation of reactive oxygen species in combination with CuSAs/MoS_(2) glutathione peroxidase-like(GSH-Px-like)for glutathione scavenging resulted in an imbalance in redox homeostasis within bacteria.CuSAs/MoS_(2),which act as nanopioneers,drive oxidative stress to initiate the process of cuproptosis-like death,leading to abnormal aggregation of lipoylated proteins and inactivation of iron-sulfur cluster proteins.Moreover,CuSAs/MoS_(2) inhibited the biosynthesis of the peptidoglycan synthesis precursors D-glutamate and m-diaminopimelic acid and disrupted the peptidoglycan cross-linking process mediated by penicillin-binding proteins,effectively blocking the compensatory cell wall remodeling pathway ofβ-lactam-resistant bacteria.Overall,CuSAs/MoS_(2) with multiple functions can not only efficiently kill bacteria but also decelerate the development of bacterial resistance to combat drug-resistant bacterial infections.
基金The authors would like to acknowledge the financial support from the National Natural Science Foundation of China(Nos.31971253)the Beijing Municipal Health Commission(Nos.BMHC-2019-9,BMHC-2018-4 and PXM2020_026275_000002)。
文摘β-type titanium alloys have attracted much attention as implant materials because of their low elastic modulus and high strength,which is closer to human bones and can avoid the problem of stress fielding and extend the lifetime of prosthetics.However,other issues,such as the infection or inflammation postimplantation,still trouble the titanium alloy's clinical application.In this paper,we developed a novel nearβ-titanium alloy(Ti-13Nb-13Zr-13Ag,TNZA)with low elastic modulus and strong antibacterial ability by the addition of Ag element followed by proper microstructure controlling,which could reduce the stress shielding and bacterial infections simultaneously.The microstructure,mechanical properties,corrosion resistance,antibacterial properties and cell toxicity were studied using SEM,electrochemical testing,mechanical test and cell tests.The results have demonstrated that TNZA alloy exhibited an elastic modulus of 75-87 GPa and a strong antibacterial ability(up to 98%reduction)and good biocompatibility.Moreover,it was also shown that this alloy's corrosion resistance was better than that of Ti-13Nb-13Zr.All the results suggested that Ti-13Nb-13Zr-13Ag might be a competitive biomedical titanium alloy.
基金financially supported by the National Natural Science Foundation of China (Nos.81071262 and 31271024)the Funding from Northeastern University, China (Nos.N141008001 and LZ2014018)Beijing Municipal Natural Science Foundation (No.7161001)
文摘Ti–3Cu alloy has shown low melting point and strong antibacterial properties against S.aureus and E.coli and thus has potential application as dental materials and orthopedic application.In this paper, the corrosion properties of Ti–3Cu alloy in five kinds of simulated solutions were investigated in comparison with cp-Ti(commercially pure titanium) by electrochemical technology and immersion experiment.Electrochemical results have demonstrated that Ti–3Cu alloy exhibited much nobler corrosion potential, lower corrosion current density and high corrosion resistance than cp-Ti in all solutions, especially in saliva-pH6.8+0.2 F and saliva-pH3.5, indicating that Ti–3Cu alloy has much better anticorrosion properties than cpTi.Immersion results have shown that Ti ion and Cu ion were released from Ti–3Cu, especially in saliva-pH6.8+0.2 F and saliva-pH3.5 solutions.Both electrochemical data and immersion results have indicated that high corrosion rate and high metal ion release rate were detected in F ion-containing solution and low-pH solution, displaying that F^- and low pH had much strong aggressive attack to cp-Ti and Ti–3Cu alloy.The corroded surface morphology was observed by scanning electron microscopy(SEM), and the roughness was tested in the end.The good corrosion resistance of antibacterial Ti–3Cu alloy suggests its great potential as a long-term biomedical application.
基金financially supported by the National Natural Science Foundation of China(Nos.82002303,51871162 and 51932002)the China National Funds for Distinguished Young Scientists(No.51925104)+2 种基金Scientific Research Foundation of Peking University Shenzhen Hospital(No.KYQD2021064)Beijing Municipal Health Commission(Nos.BMHC-2021-6,BMHC-2019-9,BMHC-2018-4 and PXM2020_026275_000002)the National Key R&D Program of China(No.R&D#2018YFA0703100)
文摘The daily life of people in the intelligent age is inseparable from electronic device,and a number of bacteria on touch screens are increasingly threatening the health of users.Herein,a photocatalytic TiO_(2)/Ag thin film was synthesized on a glass by atomic layer deposition and subsequent in situ reduction.Ultraviolet-visible(UV-Vis)spectra showed that this film can harvest the simulated solar light more efficiently than that of pristine TiO_(2).The antibacterial tests in vitro showed that the antibacterial efficiency of the TiO_(2)/Ag film against S.aureus and E.coli was 98.2%and 98.6%,under visible light irradiation for 5 min.The underlying mechanism was that the in-situ reduction of Ag on the surface of TiO_(2)reduced the bandgap of TiO_(2)from 3.44 to 2.61 eV due to the formation of Schottky heterojunction at the interface between TiO_(2)and Ag.Thus,TiO_(2)/Ag can generate more reactive oxygen species for bacterial inactivation on the surface of electronic screens.More importantly,the TiO_(2)/Ag film had great biocompatibility with/without light irradiation.The platform not only provides a more convenient choice for the traditional antibacterial mode but also has limitless possibilities for application in the field of billions of touch screens.
基金the National Natural Science Foundation of China(No.21574008)the Fundamental Research Funds for the Central Universities of China(No.BHYC1705B)。
文摘In this work,the one-step stereochemical antimicrobial finishing of cotton textiles(CT)was achieved by the oxidative copolymerization of a dopamine-menthol derivative(DAM)and dopamine(DA).The obtained DAM-modified CT(P(DAM-co-DA)-CT)exhibited broad-spectrum microbial anti-adhesion properties against bacteria(E.coli and P.aeruginosa),including superbugs(MRSA and VREF),and fungi(A.niger,A.flavus,M.racemosus and P.chrysogenum).Because of its unique stereochemical antimicrobial mechanism,the obtained P(DAM-co-DA)-CT is a non-releasing antimicrobial material that causes no skin sensitization and exhibits good biocompatibility.The coating was also found to enhance the UVresistant and mechanical properties of the CT.Furthermore,it displayed durable washing fastness and antimicrobial properties after the endurance of 30 laundering cycles.The observed achievements provide a broader understanding of stereochemical antimicrobial surfaces and endow this method with wider applications.
基金This work is sponsored by the National Key R&D Program of China(2018YFB1105504)the National Natural Science Foundation of China(81572093)This work is also supported by the funding support from Beijing Laboratory of Biomedical Materials and start-up fund from Beijing University of Chemical Technology。
文摘In the past few decades,additive manufacturing(AM)has been developed and applied as a cost-effective and versatile technique for the fabrication of geometrically complex objects in the medical industry.In this review,we discuss current advances of AM in medical applications for the generation of pharmaceuticals,medical implants,and medical devices.Oral and transdermal drugs can be fabricated by a variety of AM technologies.Different types of hard and soft clinical implants have also been realized by AM,with the goal of producing tissue-engineered constructs.In addition,medical devices used for diagnostics and treatment of various pathological conditions have been developed.The growing body of research on AM reveals its great potential in medical applications.The goal of this review is to highlight the usefulness and elucidate the current limitations of AM applications in the medical field.
基金the National Natural Science Foundation of China(Nos.51603005 and 51973010)Beijing Natural Science Foundation(No.2182052).
文摘Hydroxyapatite-graft-poly(D-lactide)(HA-g-PDLA)was synthesized by ring-opening polymerization with HA as initiator and stannous octanoate(Sn(Oct)2)as catalyst.Thermogravimetric analysis(TGA)and Fourier transform infrared spectroscopy(FUR)results indicate that PDLA chains are successfully grafted onto HA particles by covalent bond.Under two different processing temperatures(190 and 230℃),the effect of the grafted PDLA chains on the crystallization behavior of poly(L-lactide)/HA-g-PDLA(PLLA/HA-g-PDLA)composite was investigated in the current study,comparing to neat PLLA and its four composites(PLLA/HA,PLLA/HA-g-PLLA,PLLA/PDLA,and PLLA/HA/PDLA).The crystallization rate of PLLA/HA-g-PDLA composite is highly enhanced comparing to PLLA,PLLA/HA and PLLA/HA-g-PLLA composites in which there are no stereocomplex(SC)crystallites.In addition,when the processing temperature rises from 190℃ to 230℃,the acceleration of PLLA crystallization in PLLA/HA-g-PDLA composite is not influenced so much as other composites containing SC crystallites,such as PLLA/HA/PDLA or PLLA/PDLA.The differential scanning calorimetry(DSC)results demonstrate that even without SC crystallites,the crystallization of PLLA can still be accelerated a lot in this composite.This may be related to the interaction between the grafted PDLA chains and the amorphous PLLA chains in PLLA/HA-g-PDLA composite.The isothermal crystallization kinetics studies indicate that the nature of nucleation and crystal growth of PLLA/HAg-PDLA composite are more likely 3D crystalline growth with heterogeneous nucleation mode,which are different from PLLA or other composites.This investigation could shed new light on the application of PLLA/HA composites.
基金supported by the National Key R&D Program of China(No.2022YFB3804400)and(No.2022YFE0122800)Research Program(No.62602010113)+1 种基金Na-tional Natural Science Foundation of China(No.31971253/C1002)Beijing Municipal Health Commission(Nos.BMHC-2021-6,BMHC-2019-9,PXM 2020_026275_000002).
文摘Antibacterial Ti-5Cu alloy is a promising substitute material for Ti-made cardiovascular implants,so its surface engineering is crucial to expediting clinical implementation.Given the antibacterial and cardiovas-cular biological benefits of Cu^(2+)and titanium-nitride-oxide(TiN x O y)coatings,a Cu_(2)O/CuO-TiN x O y coating with upregulated Cu^(2+)release was successfully deposited on Ti-5Cu alloy for the first time using oxygen and nitrogen plasma-based surface modification.The superhydrophilic and nanostructured Cu_(2)O/CuO-TiN x O y coating had a dense structure and was well bonded to the substrate,resulting in enhanced cor-rosion resistance,while CuO/Cu_(2)O in the coating released Cu^(2+)faster than Ti_(2)Cu phase in the matrix.More gratifying,the coating demonstrated perfect antibacterial properties(R>99.9%against S.aureus),owing primarily to direct contact sterilization of Cu_(2)O/CuO.The most encouraging phenomenon was that the coating dramatically accelerated HUVEC adhesion(1.4 times),proliferation(RGR:106%-116%),and particularly migration(RMR:158%-247%)compared with the control Ti.The coating extract also signifi-cantly stimulated in vitro angiogenesis capacity.The rapid endothelialization for Cu_(2)O/CuO-TiN x O y coating was attributed to the surface nanostructure and Cu^(2+)/NO_(2)−release,which upregulated the angiogenesis-related gene expression of HIF-1α,VEGF,and eNOS to increase VEGF secretion and NO production.All of the findings indicated that the Cu_(2)O/CuO-TiN x O y coating could enhance the corrosion resistance,an-tibacterial properties,and endothelialization potential of Ti-Cu alloy,displaying great clinical potential in cardiovascular applications.
基金This work was financially supported by the National Natural Science Foundation of China(No.31971253)Beijing Municipal Health Commission(Nos.BMHC-2019-9,BMHC-2018-4 and PXM2020-026275-000002).
文摘Ti-Cu alloy has potential to be used in plastic surgery and dental implants due to its strong antibacterialproperties,high strength and good corrosion resistance.In this paper,Ti-5Cu was anodic-oxidized to enhance the surface compatibility.The influence of the oxidation on the corrosion resistance,antibacterial properties and biological properties was investigated.X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)results showed that a double-layer oxide coating with dense inner layer and porous outside layer was formed on Ti-Cu sample.The oxide coating consisted mainly of TiO2,CuzO and small amount of CuO,improved the corrosion resistance of Ti-Cu alloy by one order of magnitude due to the formation of the dense oxide inner layer,but high Cu ion release was detected.The plate count results showed that the antibac-terial activity of Ti-Cu sample was improved to≥99%due to the comprehensive function of CuO and Cu_(2)O in the coating and Cu^(2+)release.Cell test results showed that thecoating exhibited good cell compatibility,the porous sur-face structure improved the adhesion of cells,and Cu ion release promoted the cell proliferation.
基金supported by the National Natural Science Foundation of China(Nos.51503013,51390481,21774008and 81472412)supported by the Fundamental Research Funds for the Central Universities(Nos.ZY1519 and XK1701)+1 种基金the long-term subsidy mechanism from the Ministry of Financethe Ministry of Education of PRC for BUCT
文摘The synthesis and structure-property correlation of poly（N-（2-hydroxypropyl） methacrylamide） （PHPMA） conjugates with various architectures including random, block, branched or star-like structures and compositions have been thoroughly explored. However, related synthesis and structure-property data are still lacking for comb-like PHPMA. In this work, we report the synthesis of comb-like PHPMA copolymer-doxorubicin （DOX） conjugates with different backbone/side-chain lengths and location of drug moieties. Well-defined comb-like PHPMA-DOX conjugates are obtained via the combination of controlled radical polymerization and fractional precipitation techniques. The influences of structural factors on the biological properties such as cellular uptake, blood circulation and tumor accumulation have been investigated. Long blood circulation and efficient tumor accumulation can be achieved by proper control of the comb number, length and location of drug moieties. These facile comb-like structures possess great potentials in future theranostics for brachytherapy or surgical navigation.
文摘It is highly desired to have bioactive surfaces for biomaterials and controllable interactions with cells.These functions were widely achieved by attaching functional peptides to the surface of biomaterials.It is well known that an antifouling layer can help reducing the nonspecific cell attachment.However,it is unclear how an antifouling PEG layer affects the function of peptides attached on material surface in controlling cell behavior.This highlight introduced the recent JACS paper from Prof.Liu and coworkers in addressing this question thoroughly.
基金supported by the National Natural Science Foundation of China(Nos.51025314 and 21104089)the Fundamental Research Funds for the Central Universities(No.ZY1632)
文摘Porous hybrid microspheres were fabricated by the synthesized calcium gluconate-g-poly（D,L-lactide） （CG-g- PDLLA） composites. These hybrid microspheres were treated with an alkaline solution for different period of time to control the amount of generated carboxylate groups and remained CG on the surface. The microspheres were then incubated in a supersaturated simulated body fluid （1.5 SBF） solution for different time to investigate their biomimetic mineralization behavior. The depositions were found to have a fine cluster morphology, a similar crystal structure and chemical structure to natural hydroxyapatite, and a medium Ca/P of approximately 1.30. The effect of surface treating time on the structure and mineralization behavior of these microspheres has been discussed in detail. The results indicate that the nucleation and growth of apatite on the surface are influenced by the induced carboxylate groups and the remained CG. The hybrid CG-g- PDLLA microspheres have the potential as a novel alternative in bone tissue engineering.
基金the China Petrochemical Corporation and the Fundamental Research Funds for the Central Universities(Nos.XK1802-2 and XK1802-1).
文摘Poly(styrene-6-isobutylene-6-styrene)triblock copolymer(SIBS),a kind of thermoplastic elastomer with biocompatibility and biostability containing fully saturated soft segments,could be synthesized via living cationic copolymerization.A novel poly[(styrene-co-methylstyrene)-b-isobutylene-b-(styrene-co-methylstyrene)]-g-polytetrahydrofuran(M-SIBS-g-PTHF)block graft copolymer was prepared to increase the polarity and service temperature of SIBS by grafting polar PTHF segments onto SIBS.A series of the above block graft copolymers with average grafting numbers from 2 to 6 and molecular weights of PTHF branches ranging from 200 g·mol^(-1)to 4200 g·mol^(-1)were successfully synthesized via living cationic ring-opening polymerization of tetrahydrofuran(THF)coinitiated by AgCI04.The introduction of PTHF branches led to an obvious microphase separation due to thermodynamic incompatibility among the three kinds of segments of polyisobutylene(PIB),polystyrene(PS)and PTHF.Moreover,the microphase separation promotes the rearrangement of PTHF branches to form the nanocrystallization-locked physically cross-linked network after storage at room temperature for 2 months,leading to insolubility of the copolymers even in good solvents.The melting temperature and enthalpy of PTHF nanocrystallization locked in hard domains of M-SIBS-g5-PTHF-1.1k block graft copolymer increased remarkably up to 153℃and 117.0 J·g^(-1)by 23℃and 11.6 J·g^-1(respectively after storage for long time.Storage modulus(G′)is higher than loss modulus(G″)of M-SIBS-g-PTHF block graft copolymer at temperatures ranging from 100℃to 180℃,which is much higher than those of the SIBS triblock copolymer.To the best of our knowledge,this is the first example of high performance M-SIBS-g-PTHF block graft copolymers containing segments of PIB,PS and PTHF with nanocrystallization-locked architecture.
基金the National Natural Science Foundation of China(Nos.21574007 and 51521062)the Fundamental Research Funds for the Central Universities(Nos.XK1802-2 and XK1802-1).
文摘The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose(HPC)backbone and hydrophobic soft nonpolar polyisobutylene(PIB)branches have been successfully synthesized through nucleophilic substitution reaction of living PIB chains carrying oxonium ions with the-OH groups along HPC backbone.The PIB branch length in the graft copolymers could be designed by living cationic polymerization and the grafting density could be adjusted by PIB+/-OH molar ratio.The living PIB chains carrying oxonium ion were prepared by transformation of allyl bromide end groups in the presence of AgCI0_(4) and silver nanoparticles(3.2±0.3 nm,0.7 wt%-1.8 wt%)generated in situ from AgBr.The phase-separation morphology was formed in the graft copolymers due to their incompatibility between backbone and branches.The hydrophilicity on the surface of graft copolymer films could be turned to hydrophobicity by increasing grafting density or/and length of PIB branches.The soft PIB segments in graft copolymers provided an unique surface wa self-assembly for ant卜protein adsorption against bovine serum albumin.A small amount of Ag nanoparticles in the copolymers contributed to good antibacterial activities against Staphylococcus aureus or Escherichia coli.
基金supported by the National Natural Science Foundation of China (Nos. 51025314, 50973122,)the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KJCX2-YW-H19)
文摘This work focuses on the interaction between polymeric micelles with different charged surfaces and cancer cells in order to study the influence of surface charge on the in vitro cellular uptake efficiency. The amphiphilic diblock copolymers poly（e-caprolaetone）-b-poly（ethylene oxide） （PCL-b-PEO） with different functional groups at the end of hydrophilic block were synthesized. The functional groups endue the micelles with different charges on the surfaces. The cellular uptake of micelles to T-24 cells （human bladder tumor cells）, HepG2 cells （human liver hepatocellular carcinoma cell line） and Hela cells （human epithelial cervical cancer cells） was studied by means of flow cytometer and confbcal laser scanning microscopy. The results indicate that the surface charges showed great influence on zeta potential of micelles at different pH values. The in vitro cellular uptake efficiency of micelles with different charged surfaces demonstrated different cellular uptake patterns to three kinds of cancer cells.
