Nowadays,silicon has become a promising anode active material for lithium-ion batteries due to its high specific capacity.However,traditional binder materials cannot effectively restrain the volume expansion of silico...Nowadays,silicon has become a promising anode active material for lithium-ion batteries due to its high specific capacity.However,traditional binder materials cannot effectively restrain the volume expansion of silicon during lithiation/delithiation.Inspired by the growth process of climbing plants,we sequentially crosslink sodium alginate with calcium ions and hyperbranched polyethyleneimine to construct a dual crosslinked network binder.During the sequentially crosslinking,sodium alginate preferentially crosslinks with Ca^(2+)to form the"trellis"network,which restricts the free movement of hyperbranched polyethyleneimine and guides it,like"vine",to gradually anchor on the surrounding"trellis"through hydrogen and ionic bonding.In this dual crosslinked network,the ionic ally crosslinked sodium alginate maintains the anode structural integrity;the anchored hyperbranched polyethyleneimine forms strong multidimensional hydrogen bonds with silicon nanoparticles through its amino-rich branch chains;and the network utilizes the bonding reversibility of hydrogen and ionic bonds to repeatedly eliminate the mechanical stress and self-heal the structure damages caused by the volume change of silicon.Benefited from the multifunction of the dual crosslinked network,the silicon anode has achieved an excellent electrochemical performance with a specific capacity of 2403 mAh·g^(-1)at the current density of500 mA·g^(-1)after 100 cycles.展开更多
Protein-based hydrogels are promising materials for biomedical and materials science applications.However,engineer-ing hydrogels with both high stiffness and high toughness,a key requirement for many applications,rema...Protein-based hydrogels are promising materials for biomedical and materials science applications.However,engineer-ing hydrogels with both high stiffness and high toughness,a key requirement for many applications,remains challenging.Recently,by using the denatured crosslinking method,we developed highly stiff and tough protein hydrogels based on the polyprotein(FL)8 via introducing chain entanglements into the hydrogel network,which allow for stiffening the hydrogel without sacrificing toughness.These hydrogels exhibited a Young’s modulus of∼0.7 MPa and breaking strain of∼100%in tensile tests.To further enhance their stretchability and toughness,here we report the engineering of a protein/alginate hybrid hydrogel,in which the protein and alginate networks are covalently joined.Alginate was chemically modified with tyramine to introduce phenol groups,allowing the modified alginate to be photochemically crosslinked together with the polyprotein(FL)8 to form a hybrid network hydrogel.Using calcium-mediated ionic crosslinking,we demonstrated the feasibility to tune the Young’s modulus and breaking strain of these hydrogels by controlling the degree of tyramine modification of alginate.Our results showed that incorporating noncovalent ionic crosslinking into the hydrogel network increased the hydrogel’s stretchability from∼100%to over 200%without compromising stiffness,significantly improving the hydrogel’s toughness.This work expands the mechanical tunability of protein hydrogels and the repertoire of strategies for engineering hydrogels with a broad range of mechanical properties.展开更多
Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this e...Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this end,in vitro platforms are needed to test therapies directed at salivary(fluid-secreting)cells.However,since these are highly differentiated secretory cells,the maintenance of their differentiated state while expanding in numbers is challenging.In this study,the efficiency of three reversible thermo-ionically crosslinked gels:(1)alginate–gelatin(AG),(2)collagen-containing AG(AGC),and(3)hyaluronic acid-containing AG(AGHA),to recapitulate a native-like environment for human salivary gland(SG)cell expansion and 3D spheroid formation was compared.Although all gels were of mechanical properties comparable to human SG tissue(~11 kPa)and promoted the formation of 3D spheroids,AGHA gels produced larger(>100 cells/spheroid),viable(>93%),proliferative,and well-organized 3D SG spheroids while spatially and temporally maintaining the high expression of key SG proteins(aquaporin-5,NKCC1,ZO-1,α-amylase)for 14 days in culture.Moreover,the spheroids responded to agonist-induced stimulation by increasingα-amylase secretory granules.Here,we propose alternative lowcost,reproducible,and reversible AG-based 3D hydrogels that allow the facile and rapid retrieval of intact,highly viable 3D-SG spheroids.展开更多
In this research;the release of 5-Fluorouracil (5-FU) from different ionically crosslinked alginate (Alg) beads was investigated by using Fe3+, Al3+, Zn2+, and Ca2+, ions as crosslinking agent. The prepared beads were...In this research;the release of 5-Fluorouracil (5-FU) from different ionically crosslinked alginate (Alg) beads was investigated by using Fe3+, Al3+, Zn2+, and Ca2+, ions as crosslinking agent. The prepared beads were characterized by Fourier Transform Infrared Spectroscopy (FTIR) Differential Scanning Calorimetry (DSC) and Scanning Electron Micros-copy (SEM). The drug release studies were carried out at three pH values 1.2, 6.8 and 7.4 respectively each for two hours. The effects of the preparation conditions as crosslinker type, drug/polymer (w/w) ratio, crosslinker concentration and time of exposure to crosslinker on the release of 5-FU were investigated for 6 hours at 37℃. It was observed that 5-FU release from the beads followed the order of Fe > Zn > Al > Ca-Alg and increased with increasing drug/polymer ratio. At the end of 6 hours, the highest 5-FU release was found to be 90% (w/w) for Fe-Alg beads at the drug/polymer ratio of 1/8 (w/w), crosslinker concentration of 0.05 M, exposure time of 10 minutes respectively. The swelling measurements of the beads supported the release results. Release kinetics was described by Fickian and non-Fickian approaches.展开更多
Polymer light-emitting electrochemical cells (PLECs) employ a thin layer of a luminescent conjugated polymer admixed with an ionic source and an ionic conductor for the in-situ formation of p-i-n junction and subseque...Polymer light-emitting electrochemical cells (PLECs) employ a thin layer of a luminescent conjugated polymer admixed with an ionic source and an ionic conductor for the in-situ formation of p-i-n junction and subsequent efficient injections of both electrons and holes.The junction formation enables the use of air-stable conductors as the cathode and a relatively thick emissive polymer layer that is more compatible with low-cost solution-based processes.This paper overviews the operation mechanism of the PLECs,the properties and drawbacks of the devices.The employment of crosslinkable ionic conductors to stabilize the p-i-n junction is reviewed.The resulting static junction electroluminesces light at high brightness,high efficiency,and prolonged lifetime.Silver paste and carbon nanotubes can be used as the cathode,thus,PLECs were fabricated by lamination.Using single wall carbon nanotubes coated elastic substrate as both anode and cathode,the PLECs can be made highly stretchable.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52002151 and 51905526)Jiaxing Science and Technology Project(No.2020AY10018)the Key Laboratory of Yam Materials Forming and Composite Processing Technology,Zhejiang Province(open project program,No.MTC2021-10)。
文摘Nowadays,silicon has become a promising anode active material for lithium-ion batteries due to its high specific capacity.However,traditional binder materials cannot effectively restrain the volume expansion of silicon during lithiation/delithiation.Inspired by the growth process of climbing plants,we sequentially crosslink sodium alginate with calcium ions and hyperbranched polyethyleneimine to construct a dual crosslinked network binder.During the sequentially crosslinking,sodium alginate preferentially crosslinks with Ca^(2+)to form the"trellis"network,which restricts the free movement of hyperbranched polyethyleneimine and guides it,like"vine",to gradually anchor on the surrounding"trellis"through hydrogen and ionic bonding.In this dual crosslinked network,the ionic ally crosslinked sodium alginate maintains the anode structural integrity;the anchored hyperbranched polyethyleneimine forms strong multidimensional hydrogen bonds with silicon nanoparticles through its amino-rich branch chains;and the network utilizes the bonding reversibility of hydrogen and ionic bonds to repeatedly eliminate the mechanical stress and self-heal the structure damages caused by the volume change of silicon.Benefited from the multifunction of the dual crosslinked network,the silicon anode has achieved an excellent electrochemical performance with a specific capacity of 2403 mAh·g^(-1)at the current density of500 mA·g^(-1)after 100 cycles.
基金supported by the Natural Sciences and Engineering Research Council of Canada.
文摘Protein-based hydrogels are promising materials for biomedical and materials science applications.However,engineer-ing hydrogels with both high stiffness and high toughness,a key requirement for many applications,remains challenging.Recently,by using the denatured crosslinking method,we developed highly stiff and tough protein hydrogels based on the polyprotein(FL)8 via introducing chain entanglements into the hydrogel network,which allow for stiffening the hydrogel without sacrificing toughness.These hydrogels exhibited a Young’s modulus of∼0.7 MPa and breaking strain of∼100%in tensile tests.To further enhance their stretchability and toughness,here we report the engineering of a protein/alginate hybrid hydrogel,in which the protein and alginate networks are covalently joined.Alginate was chemically modified with tyramine to introduce phenol groups,allowing the modified alginate to be photochemically crosslinked together with the polyprotein(FL)8 to form a hybrid network hydrogel.Using calcium-mediated ionic crosslinking,we demonstrated the feasibility to tune the Young’s modulus and breaking strain of these hydrogels by controlling the degree of tyramine modification of alginate.Our results showed that incorporating noncovalent ionic crosslinking into the hydrogel network increased the hydrogel’s stretchability from∼100%to over 200%without compromising stiffness,significantly improving the hydrogel’s toughness.This work expands the mechanical tunability of protein hydrogels and the repertoire of strategies for engineering hydrogels with a broad range of mechanical properties.
基金support from Fonds de Recherche du Québec Santé(FRQS,grant no.281271)support from FRQS doctoral award #304367funding from CFI,Rheolution Inc.,and Investissement Québec.
文摘Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this end,in vitro platforms are needed to test therapies directed at salivary(fluid-secreting)cells.However,since these are highly differentiated secretory cells,the maintenance of their differentiated state while expanding in numbers is challenging.In this study,the efficiency of three reversible thermo-ionically crosslinked gels:(1)alginate–gelatin(AG),(2)collagen-containing AG(AGC),and(3)hyaluronic acid-containing AG(AGHA),to recapitulate a native-like environment for human salivary gland(SG)cell expansion and 3D spheroid formation was compared.Although all gels were of mechanical properties comparable to human SG tissue(~11 kPa)and promoted the formation of 3D spheroids,AGHA gels produced larger(>100 cells/spheroid),viable(>93%),proliferative,and well-organized 3D SG spheroids while spatially and temporally maintaining the high expression of key SG proteins(aquaporin-5,NKCC1,ZO-1,α-amylase)for 14 days in culture.Moreover,the spheroids responded to agonist-induced stimulation by increasingα-amylase secretory granules.Here,we propose alternative lowcost,reproducible,and reversible AG-based 3D hydrogels that allow the facile and rapid retrieval of intact,highly viable 3D-SG spheroids.
基金The authors are grateful to the Gazi University Scientific Research Foundation for support of this study.
文摘In this research;the release of 5-Fluorouracil (5-FU) from different ionically crosslinked alginate (Alg) beads was investigated by using Fe3+, Al3+, Zn2+, and Ca2+, ions as crosslinking agent. The prepared beads were characterized by Fourier Transform Infrared Spectroscopy (FTIR) Differential Scanning Calorimetry (DSC) and Scanning Electron Micros-copy (SEM). The drug release studies were carried out at three pH values 1.2, 6.8 and 7.4 respectively each for two hours. The effects of the preparation conditions as crosslinker type, drug/polymer (w/w) ratio, crosslinker concentration and time of exposure to crosslinker on the release of 5-FU were investigated for 6 hours at 37℃. It was observed that 5-FU release from the beads followed the order of Fe > Zn > Al > Ca-Alg and increased with increasing drug/polymer ratio. At the end of 6 hours, the highest 5-FU release was found to be 90% (w/w) for Fe-Alg beads at the drug/polymer ratio of 1/8 (w/w), crosslinker concentration of 0.05 M, exposure time of 10 minutes respectively. The swelling measurements of the beads supported the release results. Release kinetics was described by Fickian and non-Fickian approaches.
基金supported by the National Science Foundation (ECCS1028412)
文摘Polymer light-emitting electrochemical cells (PLECs) employ a thin layer of a luminescent conjugated polymer admixed with an ionic source and an ionic conductor for the in-situ formation of p-i-n junction and subsequent efficient injections of both electrons and holes.The junction formation enables the use of air-stable conductors as the cathode and a relatively thick emissive polymer layer that is more compatible with low-cost solution-based processes.This paper overviews the operation mechanism of the PLECs,the properties and drawbacks of the devices.The employment of crosslinkable ionic conductors to stabilize the p-i-n junction is reviewed.The resulting static junction electroluminesces light at high brightness,high efficiency,and prolonged lifetime.Silver paste and carbon nanotubes can be used as the cathode,thus,PLECs were fabricated by lamination.Using single wall carbon nanotubes coated elastic substrate as both anode and cathode,the PLECs can be made highly stretchable.
