The effects to elicit resistance reaction on oilseed rape (Brassica napus L. cv Xinongchangjiao ) by four partially N-acetylated chitosan 7B, 8B, 9B and 10B (Degree of acetylation (D. A.) is 30% , 20% , 10%, 0%, respe...The effects to elicit resistance reaction on oilseed rape (Brassica napus L. cv Xinongchangjiao ) by four partially N-acetylated chitosan 7B, 8B, 9B and 10B (Degree of acetylation (D. A.) is 30% , 20% , 10%, 0%, respectively) and Glycol chitosan (GC, D.A. is 0%) were investigated and compared. Results showed that chitosan were similar to salicylic acid (SA), and could induce resistance reaction, but the reaction was influenced by the degree of acetylation of chitosan. Fully deacetylated chitosans, 10B and GC, elicited chitinase activity, but partially acetylated chitosan, 7B, 8B and 9B, inhibited chitinase activity. Phenyalanine ammonia-lyase (PAL) was also elicited. Elicitor activity increased with on increasing degree of acetylation, 7B induced highest PAL activity among all chitosans. All chitosans induced peroxidase (POD) in a similar level. After elicited by glycol chitosan, like SA treatment, the seedlings increased disease resistance to Sclerotinia sclerotiorum significantly.展开更多
Original chitosan with M-v of 2.7 x 10(5) was degraded by irradiation with gamma-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinet...Original chitosan with M-v of 2.7 x 10(5) was degraded by irradiation with gamma-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinetic model of the irradiation of chitosan was put forward. Results show that the irradiation degradation of chitosan obeys the rule of random degradation and the degree of deacetylation of irradiated chitosan is slightly raised. The antibacterial activity of O-CMCh is significantly influenced by its MW, and a suppositional antibacterial peak appears when M-v is equal to 2 x 10(5).展开更多
The purpose of this research is to investigate the effects of the variously sulfated chitosans on lysozyme activity and structure. It was shown that the specific enzymatic activity of lysozyme remained almost similar ...The purpose of this research is to investigate the effects of the variously sulfated chitosans on lysozyme activity and structure. It was shown that the specific enzymatic activity of lysozyme remained almost similar to the native protein after being bound to 6-O-sulfated chitosan （6S-chitosan） and 3,6-O-sulfated chitosan （3,6S-chitosan）, but decreased greatly after being bound to 2-N-6-O-sulfated chitosan （2,6S-chitosan）. Meanwhile, among these sulfated chitosans, 2,6S-chitosan induced the greatest conformational change in lysozyme as indicated by the fluorescence spectra. These findings demonstrated that when sulfated chitosans of different structures bind to lysozyme, lysozyme undergoes conformational change of different magnitudes, which results in corresponding levels of lysozyme activity. Further study on the interaction of sulfated chitosans with lysozyme by surface plasmon resonance （SPR） suggested that their affinities might be determined by their molecular structures.展开更多
Five kinds of carboxymethyl sulfochitosans with different regions such as N-carboxymethyl-O-sulfochitosan, O-carboxymethyl-N-sulfochitosan, O-carboxymethyl chitosan sulfate, N-carboxymethyl chitosan-6-sulfate, and N,O...Five kinds of carboxymethyl sulfochitosans with different regions such as N-carboxymethyl-O-sulfochitosan, O-carboxymethyl-N-sulfochitosan, O-carboxymethyl chitosan sulfate, N-carboxymethyl chitosan-6-sulfate, and N,O-carboxymethyl -N,O-sulfochitosan were prepared respectively by using differential carboxymethylation and sulfation methods, and their IR spectrum and 13C-NMR spectrum were measured.展开更多
Chitosan is a biopolymer obtained from chitin, where the N-acetylglucosamine monomer is in its deacetylated form; this polymer is useful for a wide variety of industrial applications. The properties and uses of chitos...Chitosan is a biopolymer obtained from chitin, where the N-acetylglucosamine monomer is in its deacetylated form; this polymer is useful for a wide variety of industrial applications. The properties and uses of chitosan depend on its physical and chemical characteristics, which result from the treatments used for its production. In this study, we report the preparation and characterization ofchitosan oligosaccharides by a green synthesis from crystalline shrimp chitin, using a sequential enzyme treatment by chitinase and chitin deacetylase. Chitinases were purified from grapes and used to rupture the crystalline shrimp chitin structure, modifying the crystallinity index from 57.6% to 15.9%. The resultant polymers were deacetylated using a recombinant chitin deacetylase from Saccharomyces cerevisiae, which was cloned and expressed in Pichia pastoris. The chitosans produced showed an estimated DA （degree of acetylation） of approximately 20%, and the molecular weights ranged from -7,600 to -3,700 after treatment in pH 3.0 and pH 6.0 for 10 min and 40 min, respectively. Physical and chemical characterization of the products indicated that enzyme fragmentation of chitin probably makes the acetamide groups more accessible to deacetylation, forming homogeneous polymers that are free of hazardous sub-products, have defined low molecular weights, and are highly deacetylated.展开更多
Chitosan(CS),a natural polymer derived from chitin found in the exoskeletons of crustaceans,has garnered significant interest in the pharmaceutical field due to its unique properties,including biocompatibility and bio...Chitosan(CS),a natural polymer derived from chitin found in the exoskeletons of crustaceans,has garnered significant interest in the pharmaceutical field due to its unique properties,including biocompatibility and biodegradability.In recent years,various studies have reported that CS can affect drug bioavailability,and interestingly,it works as an oral absorption enhancer and inhibitor.This review offers an in-depth analysis of the mechanisms underlying such a phenomenon and supports its application as a pharmaceutical excipient.CS enhances oral drug absorption through various mechanisms,such as interaction with the intestinal mucosa,tight junction modulation,inhibition of efflux transporters,enzyme inhibition,solubility and stability enhancement,and complexation.On the other side,CS exhibits the ability to inhibit the absorption of certain drugs by adsorbing to lipids and sterols,modulating bile acids and gut microbiota,altering drug-cell interaction at the polar interface,and mucus-mediated entrapment and interference.Future potential pharmaceutical research in this field includes elucidating the underneath absorption relevant mechanisms,rational use in formulations as excipient,exploring functional CS derivatives,and developing CS-based drug delivery systems.This comprehensive review highlights CS's versatile and significant role in enhancing and inhibiting oral drug absorption,providing insights into the complexities of drug delivery and the potential of CS to improve therapeutic outcomes.展开更多
In recent years,the addition of probiotics into non-dairy beverages has gained popularity.Probiotics offer a wider range of options for individuals who are sensitive to dairy products.Incorporating probiotics into wid...In recent years,the addition of probiotics into non-dairy beverages has gained popularity.Probiotics offer a wider range of options for individuals who are sensitive to dairy products.Incorporating probiotics into widely consumed beverages like carbonated soft drinks poses a notable challenge due to the detrimental impact of acidic pH.Herein,results demonstrate that chitosan-coated alginate/gellan gum microcapsules can enhance the viability of probiotics within carbonated soft drinks.The probiotics,Lactobacillus casei,are encapsulated in microcapsules and exposed to Pepsi,Fanta Strawberry,Sprite,and A&W Root Beer under 4 and 25℃for 60 days and simulated gastrointestinal tract.Microcapsules greatly improve the viability of adding probiotics in different beverages under simulated gastrointestinal tract.The probiotics had a gradual release from microcapsules,reaching maximum release within initial 2 h of simulated intestinal phase.During 4℃storage compared to storage at 25℃,it was found that the number of surviving cells is more than the recommended minimum(10^(6)CFU/g)at the end of the storage.The pH and soluble solids content of beverages containing microcapsules also signify little change.This work shows that the chitosan-coated alginate/gellan microcapsules have the potential to be used as protective microcapsules for probiotics in carbonated soft drinks.展开更多
Proton exchange membrane(PEM)is an integral component in fuel cells which enables proton transport for efficient energy conversion.Sulfonated Polyether Ether Ketone(SPEEK)has emerged as a cost-effective option with no...Proton exchange membrane(PEM)is an integral component in fuel cells which enables proton transport for efficient energy conversion.Sulfonated Polyether Ether Ketone(SPEEK)has emerged as a cost-effective option with non-fluorinated aromatic backbones for Proton Exchange Membrane Fuel Cell(PEMFC)applications,even though it exhibits lower proton conductivity compared to Nafion.This work aims to study the influence of Sulfonated Chitosan(SCS)concentrations on proton conductivity of SPEEK-based PEM at room temperature.SPEEK was synthesized using a sulfonation process with concentrated sulfuric acid at room temperature.SCS was synthesized via reflux of CS and 1.2 M H2SO4 with a ratio of 1:35(w/v)at 90℃ for 30 min.The composite membranes of SPEEK-SCS were formed with four different SCS concentrations,using the solution castingmethod,andDimethyl Sulfoxide(DMSO)was used as a solvent.The composite membranes synthesized include pure SPEEK(S0),SPEEK with 1%SCS(S1),SPEEK with 2%SCS(S2),and SPEEK with 3%SCS(S3).Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),water uptake,degree of swelling,Ionic exchange capacity(IEC)with Electrochemical impedance spectroscopy(EIS)were used to characterize the composite membranes in terms of composition,crystallinity,water absorption,dimensional changes,number of exchangeable ions in membranes,and proton conductivity,respectively.Notably,S3 had the highest water uptake and the lowest degree of swelling.S2 had the highest proton conductivity among the SPEEK-SCS composite membranes at room temperature with 3.44×10^(−2) Scm^(-1).展开更多
Many adsorbents have been developed for uranium recovery to ensure global energy and environmental security.However,most reported adsorbents involve complex preparation process and rely heavily on petrochemical feedst...Many adsorbents have been developed for uranium recovery to ensure global energy and environmental security.However,most reported adsorbents involve complex preparation process and rely heavily on petrochemical feedstocks,which undoubtedly increases carbon emissions from production in the nuclear industry.Here,a biomass aerogel(CS-BT)is prepared by the facile cross-linking of chitosan and bayberry tannins with glutaraldehyde.U(Ⅵ)can be adsorbed by hydroxyl groups on CS-BT aerogel via chelation,and the maximum adsorption capacity of the obtained aerogel to U(Ⅵ)is 140 mg·g^(-1)and the removal rate reaches up to 99%(at 298.15 K,pH=5.0).The pseudo-second-order kinetics model and Freundlich model can better match the adsorption process of CS-BT aerogel,implying that its adsorption is a chemical adsorption process dominated by multilayer adsorption.The thermodynamic results show that the adsorption process of U(Ⅵ)by CS-BT aerogel is spontaneous and exothermic.Hence,our biomass aerogel can effectively extract uranium from water,contributing to the sustainable development of the nuclear industry.展开更多
The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have ...The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have started using biostimulants such as chitosan and plant growth promoting bacteria instead of agrochemicals due to their environmental and health benefits.This study evaluated the effect of Bacillus subtilis and chitosan,both individually and combined,on the growth,yield,and fruit quality of Soledad pepper under greenhouse conditions.Four treatments were applied at different stages of the crop cycle:Q(Chitosan),BS(Bacillus subtilis),Q+BS(Chitosan+Bacillus subtilis),and T(Control).The results showed that the combination of chitosan and Bacillus subtilis significantly improved plant growth,especially in height and stem diameter.The chitosan treatment produced the highest number of fruits and plant weight,while the combination of chitosan and Bacillus subtilis enhanced fruit quality,increasing characteristics such as size,weight,pericarp thickness,and physicochemical parameters,notably in brix degrees,citric acid percentage,and pH,outperforming the individual treatments and the control.展开更多
Studies have shown that chitosan protects against neurodegenerative diseases. However, the precise mechanism remains poorly understood. In this study, we administered chitosan intragastrically to an MPTP-induced mouse...Studies have shown that chitosan protects against neurodegenerative diseases. However, the precise mechanism remains poorly understood. In this study, we administered chitosan intragastrically to an MPTP-induced mouse model of Parkinson's disease and found that it effectively reduced dopamine neuron injury, neurotransmitter dopamine release, and motor symptoms. These neuroprotective effects of chitosan were related to bacterial metabolites, specifically shortchain fatty acids, and chitosan administration altered intestinal microbial diversity and decreased short-chain fatty acid production in the gut. Furthermore, chitosan effectively reduced damage to the intestinal barrier and the blood–brain barrier. Finally, we demonstrated that chitosan improved intestinal barrier function and alleviated inflammation in both the peripheral nervous system and the central nervous system by reducing acetate levels. Based on these findings, we suggest a molecular mechanism by which chitosan decreases inflammation through reducing acetate levels and repairing the intestinal and blood–brain barriers, thereby alleviating symptoms of Parkinson's disease.展开更多
Chitin and its deacetylated derivative chitosan are the major components of fungal cell walls and are recognized by plant pattern-recognition receptors(PRRs)as pathogen-associated molecular patterns that induce innate...Chitin and its deacetylated derivative chitosan are the major components of fungal cell walls and are recognized by plant pattern-recognition receptors(PRRs)as pathogen-associated molecular patterns that induce innate immunity.Recognition of chitin oligosaccharide(CTOS)in Arabidopsis(Arabidopsis thaliana)and rice(Oryza sativa)requires the membrane-localized lysin-motif(LysM)-domain-containing receptors AtLYK5and OsCEBiP,respectively.However,the mechanism underlying chitosan oligosaccharide(CSOS)-induced plant immunity remains unclear.In this study,we determined that CTOS and CSOS trigger immune responses and boost disease resistance in soybean(Glycine max)through the LysM-domain-containing protein GmNRF5a and its co-receptor GmCERK1.Surprisingly,both GmNFR5a and GmCERK1 bind directly to CTOS and CSOS,with distinct binding sites.The receptor-like kinase GmCAK1 acts downstream of GmCERK1 and is essential for CTOS/CSOSmediated immune activation.Overall,these findings uncovered how soybean plants respond to CSOS and initiate immune signaling,demonstrating that soybean exploits shared immune sectors to transduce immune signals triggered by CTOS/CSOS,paving the way for the development of disease-resistant crops with broad-spectrum resistance.展开更多
The potent antibacterial activity of silver nanoparticles is primarily attributed to the release of silver ions,which disrupt cell membranes and inactivate essential enzymes through Ag−S bonding formation.[Objective]T...The potent antibacterial activity of silver nanoparticles is primarily attributed to the release of silver ions,which disrupt cell membranes and inactivate essential enzymes through Ag−S bonding formation.[Objective]To explore silver ion immobilization to minimize silver release.[Methods]A macrocyclic cryptand with nitrogen bridgeheads was prepared and subsequently chelated with silver ions to produce Cage silver(I),which was then coordinated with different ratios of sulfonated chitosan(SCS)to form SCS/Cage Ag(I)complexes(SCA1,SCA2,and SCA3).The antioxidant activities of the complexes were assessed by reducing power and 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical and hydrogen peroxide scavenging assays.The antibacterial activities of the complexes were evaluated based on the minimum inhibitory concentrations(MICs)and minimum bactericidal concentrations(MBCs)against Staphylococcus aureus ATCC 6538 and Escherichia coli O157:H7 and the inhibition rate on biofilm formation.[Results]Cage silver(I)exhibited strong antibacterial activity,with the MIC of 0.015 mg/mL and MBC of 0.031 mg/mL against S.aureus ATCC 6538,and the MIC of 0.031 mg/mL and MBC of 0.120 mg/mL against E.coli O157:H7.Significant antioxidant properties of Cage silver(I)were also observed,as demonstrated by the DPPH free radical scavenging rates of 42.2%and 53.1%at 326 nm and 517 nm,respectively.Cage silver(I)exhibited the highest antibacterial and antioxidant activities,followed by SCA1,SCA2,SCA3,and SCS,because the content of silver ions in Cage silver(I)was 10-fold higher than that in SCA1.The antibacterial and antioxidant activities of SCA1 were better than those of Cage silver(I),which further indicated that the sulfonic groups of SCS may intensely coordinate with silver ions to exert synergistic effects.[Conclusion]Combining the merits of silver ions and SCS improves the bioavailability of the agent at microbicidal concentrations,minimizes the accumulation in the environment,and reduces treatment costs.The method developed herein offers a sustainable approach to enhance microbial control while minimizing the impact on the environment.展开更多
The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)...The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.展开更多
The ability to replicate the microenvironment of the human body through the fabrication of scaffolds is a significant achievement in the biomedical field.However,the search for the ideal scaffold is still in its infan...The ability to replicate the microenvironment of the human body through the fabrication of scaffolds is a significant achievement in the biomedical field.However,the search for the ideal scaffold is still in its infancy and there are significant challenges to overcome.In the modern era,the scientific community is increasingly turned to natural substances due to their superior biological ability,lower cost,biodegradability,and lower toxicity than synthetic lab-made products.Chitosan is a well-known polysaccharide that has recently garnered a high amount of attention for its biological activities,especially in 3D bone tissue engineering.Chitosan closely matches the native tissues and thus stands out as a popular candidate for bioprinting.This review focuses on the potential of chitosan-based scaffolds for advancements and the drawbacks in bone treatment.Chitosan-based nanocomposites have exhibited strong mechanical strength,water-trapping ability,cellular interaction,and biodegradability.Chitosan derivatives have also encouraged and provided different routes for treatment and enhanced biological activities.3D tailored bioprinting has opened new doors for designing and manufacturing scaffolds with biological,mechanical,and topographical properties.展开更多
Electrospinning has gained significant importance across various fields,including biomedicine,filtration,and packaging due to the control it provides over the properties of the resulting materials,such as fiber diamet...Electrospinning has gained significant importance across various fields,including biomedicine,filtration,and packaging due to the control it provides over the properties of the resulting materials,such as fiber diameter and membrane thickness.Chitosan is a biopolymer that can be utilized with both natural and synthetic copolymers,owing to its therapeutic potential,biocompatibility,and biodegradability.However,producing electrospun chitosan is challenging due to its high solution viscosity,which often results in the formation of beads instead of uniform fibers.To address this issue,the spinnability of chitosan is significantly enhanced,and the production of continuous nanofibers is facilitated by combining it with polymers such as polyethylene oxide(PEO)in suitable ratios.These chitosan–PEO nanofibers are primarily used in biomedical applications,including wound healing,drug delivery systems,and tissue engineering scaffolds.Additionally,they have shown promise in water treatment,filtration membranes,and packaging.Among all the nanofiber mats,chitosan/PEO-AC had the smallest fiber diameter(83±12.5 nm),chitosan/PEO_45S5 had the highest tensile strength(1611±678 MPa).This comprehensive review highlights recent advancements,ongoing challenges,and future directions in the electrospinning of chitosan-based fibers assisted by PEO.展开更多
CRISPR-Cas system permanently deletes any harmful gene-of-interest to combat cancer growth.Chitosan(CS)is a potential cancer therapeutic that mediates via PI3K/Akt/mTOR,MAPK and NF-kβsignaling pathway modulation.CS a...CRISPR-Cas system permanently deletes any harmful gene-of-interest to combat cancer growth.Chitosan(CS)is a potential cancer therapeutic that mediates via PI3K/Akt/mTOR,MAPK and NF-kβsignaling pathway modulation.CS and its covalent derivatives have been designed as nanocarrier of CRISPR-Cas9 alone(plasmid or ribonucleoprotein)or in combination with chemical drug for cancer treatment.The nanocarrier was functionalized with polyethylene glycol(PEG),targeting ligand,cell penetrating ligand and its inherent positive zeta potential to mitigate premature clearance and particulate aggregation,and promote cancer cell/nucleus targeting and permeabilization to enable CRISPR-Cas9 acting on the host DNA.Different physicochemical attributes are required for the CS-based nanocarrier to survive from the administration site,through the systemic circulation-extracellular matrix-mucus-mucosa axis,to the nucleus target.CRISPR-Cas9 delivery is met with heterogeneous uptake by the cancer cells.Choice of excipients such as targeting ligand and PEG may be inappropriate due to lacking overexpressed cancer receptor or availability of excessive metabolizing enzyme and immunoglobulin that defies the survival and action of these excipients rendering nanocarrier fails to reach the target site.Cancer omics analysis should be implied to select excipients which meet the pathophysiological needs,and chitosan nanocarrier with a“transformative physicochemical behavior”is essential to succeed CRISPR-Cas9 delivery.展开更多
MicroRNAs(miRNAs)are abundant in the brain and mounting evidence suggests their involvement in the critical processes such as neurodevelopment,synaptic plasticity,and the development of neurodegenerative diseases.Thus...MicroRNAs(miRNAs)are abundant in the brain and mounting evidence suggests their involvement in the critical processes such as neurodevelopment,synaptic plasticity,and the development of neurodegenerative diseases.Thus,miRNAs may be promising therapeutic drugs for the treatment of neurodegenerative disorders.However,naked miRNAs are not able to enter cells directly,especially brain cells.Therefore,suitable carriers for safe and efficient miRNA delivery to brain cells are of great importance.Chitosan nanoparticles,with the excellent properties such as good compatibility and brilliant degradability,may act as a promising carrier for miRNA drug delivery.In this study,chitosan nanoparticles were prepared and their properties such as particle size,zeta potential and encapsulation efficiency were optimized to encapsulate miRNAs.The delivery efficiency of miRNA-loaded nanoparticles was then evaluated in both neuronal and microglia cells.The results demonstrated chitosan nanoparticles encapsulated miRNAs efficiently and showed excellent sustained releasing in vitro.Moreover,chitosan nanoparticles delivered miRNA to both neurons and microglia with very low toxicity and high efficiency.In conclusion,chitosan nanoparticles are promising carriers for the delivery of miRNAs to brain cells,which may be used for the early intervention and treatment of neurodegenerative disorders.展开更多
Objective:To develop chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms and verify their antibacterial performance through animal experiments.Methods:Chitosan,silver nitrate,glacial acetic acid,an...Objective:To develop chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms and verify their antibacterial performance through animal experiments.Methods:Chitosan,silver nitrate,glacial acetic acid,and other chemical reagents were used to synthesize chitosan-silver nanoparticles.The characterization,minimum inhibitory concentration,and biofilm inhibition rate of the chitosan-silver nanoparticles were tested.A total of 40 SD rats were randomly divided into four groups.After routine adaptive feeding,the control group received intraperitoneal injection of normal saline;the model group received intraperitoneal injection of Pseudomonas aeruginosa suspension;the positive group received intraperitoneal injection of Pseudomonas aeruginosa suspension mixed with ampicillin at a volume ratio of 1∶1;the observation group received intraperitoneal injection of Pseudomonas aeruginosa suspension mixed with chitosan-silver nanoparticles(at minimum inhibitory concentration)at a volume ratio of 1∶1.Bacterial load,inflammatory factors,and liver and kidney function indicators in tissues were observed and compared among the four groups on the 3^(rd)day after treatment.Results:When the concentration of chitosansilver nanoparticles reached 8μg/mL or above,the OD value of the experimental wells was close to that of the control wells,indicating that 8μg/mL was the minimum inhibitory concentration of the chitosan-silver nanoparticles;at concentrations of 8μg/mL or above,the biofilm inhibition rate was greater than 80%.The bacterial load in the observation group was significantly lower than that in the model and positive groups(P<0.05).The expression levels of interleukin-6,interferon-γ,and tumor necrosis factor-αin the observation group were significantly lower than those in the model and positive groups(P<0.05).There were no statistically significant differences in alanine aminotransferase,aspartate aminotransferase,blood urea nitrogen,and creatinine levels among the four groups(P>0.05).Conclusion:The chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms constructed in this study exhibit good antibacterial effects against Pseudomonas aeruginosa and have good safety.展开更多
This study aimed to assess the therapeutic potential of nisin,5-fluorouracil(5FU)and selenium encapsulated in folate-conjugated thiolated chitosan nanoparticles(N/5FU/Se@FTCsNPs),combined with a probiotic cocktail of ...This study aimed to assess the therapeutic potential of nisin,5-fluorouracil(5FU)and selenium encapsulated in folate-conjugated thiolated chitosan nanoparticles(N/5FU/Se@FTCsNPs),combined with a probiotic cocktail of Lactobacillus acidophilus and Bifidobacterium bifidum,against colorectal cancer(CRC).The nanoparticles(277 nm,+9.2 mV)exhibited high drug loading efficiencies(5FU:89.11%,nisin:70.68%)and pH-responsive release,with minimal drug release under gastric conditions and∼60.7%release at colonic pH,facilitating targeted delivery.The formulation remained stable for over 40 d at−20°C and 4°C,demonstrating excellent biocompatibility(<2%hemolysis)and exhibiting strong mucoadhesive and mucus-penetrating abilities.In vitro,N/5FU/Se@FTCsNPs selectively targeted CT26 colon cancer cells(IC5n:1.57μg/ml)with minimal effects on healthy cells,enhanced cellular uptake,and induced ROS-mediated apoptosis.In vivo,oral administration-especially with probiotics-significantly reduced tumor volume,improved survival rates and alleviated chemotherapy-related side effects such as diarrhea and weight loss.Biodistribution studies confirmed increased tumor targeting and decreased off-target exposure.Mechanistically,the treatment downregulated oncogenes and inflammatory markers(2-to 12.5-fold),includingβ-catenin,mTOR,COX-2 and VEGF-α,while upregulating tumor suppressors and protective genes(4 to 14.8 fold),such as PTEN,CASP9 and Mucin 2(P<0.0001).This indicates inhibition of proliferation,metastasis,inflammation,and angiogenesis,along with improved gut barrier function.Cytokine profiling and histological analysis further confirmed reduced systemic inflammation and maintained hematological safety.These findings highlight N/5FU/Se@FTCsNPs combined with probiotics as a promising,safe and effective oral therapy for CRC,leveraging microbiota modulation and targeted delivery.展开更多
文摘The effects to elicit resistance reaction on oilseed rape (Brassica napus L. cv Xinongchangjiao ) by four partially N-acetylated chitosan 7B, 8B, 9B and 10B (Degree of acetylation (D. A.) is 30% , 20% , 10%, 0%, respectively) and Glycol chitosan (GC, D.A. is 0%) were investigated and compared. Results showed that chitosan were similar to salicylic acid (SA), and could induce resistance reaction, but the reaction was influenced by the degree of acetylation of chitosan. Fully deacetylated chitosans, 10B and GC, elicited chitinase activity, but partially acetylated chitosan, 7B, 8B and 9B, inhibited chitinase activity. Phenyalanine ammonia-lyase (PAL) was also elicited. Elicitor activity increased with on increasing degree of acetylation, 7B induced highest PAL activity among all chitosans. All chitosans induced peroxidase (POD) in a similar level. After elicited by glycol chitosan, like SA treatment, the seedlings increased disease resistance to Sclerotinia sclerotiorum significantly.
基金This work was supported by the National Natural Science Foundation of China (No. 50173019).
文摘Original chitosan with M-v of 2.7 x 10(5) was degraded by irradiation with gamma-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinetic model of the irradiation of chitosan was put forward. Results show that the irradiation degradation of chitosan obeys the rule of random degradation and the degree of deacetylation of irradiated chitosan is slightly raised. The antibacterial activity of O-CMCh is significantly influenced by its MW, and a suppositional antibacterial peak appears when M-v is equal to 2 x 10(5).
基金supported by the National Natural Science Foundation of China(Nos.20920102035,20974086, and 21074083)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The purpose of this research is to investigate the effects of the variously sulfated chitosans on lysozyme activity and structure. It was shown that the specific enzymatic activity of lysozyme remained almost similar to the native protein after being bound to 6-O-sulfated chitosan （6S-chitosan） and 3,6-O-sulfated chitosan （3,6S-chitosan）, but decreased greatly after being bound to 2-N-6-O-sulfated chitosan （2,6S-chitosan）. Meanwhile, among these sulfated chitosans, 2,6S-chitosan induced the greatest conformational change in lysozyme as indicated by the fluorescence spectra. These findings demonstrated that when sulfated chitosans of different structures bind to lysozyme, lysozyme undergoes conformational change of different magnitudes, which results in corresponding levels of lysozyme activity. Further study on the interaction of sulfated chitosans with lysozyme by surface plasmon resonance （SPR） suggested that their affinities might be determined by their molecular structures.
基金supported by the Development Project of Science and Technology of Qingdao(02-1-Kchhh-58)National‘863’High Technology Project of China(819-07-03)
文摘Five kinds of carboxymethyl sulfochitosans with different regions such as N-carboxymethyl-O-sulfochitosan, O-carboxymethyl-N-sulfochitosan, O-carboxymethyl chitosan sulfate, N-carboxymethyl chitosan-6-sulfate, and N,O-carboxymethyl -N,O-sulfochitosan were prepared respectively by using differential carboxymethylation and sulfation methods, and their IR spectrum and 13C-NMR spectrum were measured.
文摘Chitosan is a biopolymer obtained from chitin, where the N-acetylglucosamine monomer is in its deacetylated form; this polymer is useful for a wide variety of industrial applications. The properties and uses of chitosan depend on its physical and chemical characteristics, which result from the treatments used for its production. In this study, we report the preparation and characterization ofchitosan oligosaccharides by a green synthesis from crystalline shrimp chitin, using a sequential enzyme treatment by chitinase and chitin deacetylase. Chitinases were purified from grapes and used to rupture the crystalline shrimp chitin structure, modifying the crystallinity index from 57.6% to 15.9%. The resultant polymers were deacetylated using a recombinant chitin deacetylase from Saccharomyces cerevisiae, which was cloned and expressed in Pichia pastoris. The chitosans produced showed an estimated DA （degree of acetylation） of approximately 20%, and the molecular weights ranged from -7,600 to -3,700 after treatment in pH 3.0 and pH 6.0 for 10 min and 40 min, respectively. Physical and chemical characterization of the products indicated that enzyme fragmentation of chitin probably makes the acetamide groups more accessible to deacetylation, forming homogeneous polymers that are free of hazardous sub-products, have defined low molecular weights, and are highly deacetylated.
基金financially supported by National Key Research and Development Program of China (No.2021YFD1800900)National Natural Science Foundation of China (No.82073790)+2 种基金Special Fund for Youth Team of Southwest University (No.SWUXJLJ202306)Chongqing Science and Technology Commission (Nos.CSTB2022TIAD-LUX0001,CSTB2023NSCQ-JQX0002)Innovation Research 2035 Pilot Plan of Southwest University (No.SWUXDPY22007)。
文摘Chitosan(CS),a natural polymer derived from chitin found in the exoskeletons of crustaceans,has garnered significant interest in the pharmaceutical field due to its unique properties,including biocompatibility and biodegradability.In recent years,various studies have reported that CS can affect drug bioavailability,and interestingly,it works as an oral absorption enhancer and inhibitor.This review offers an in-depth analysis of the mechanisms underlying such a phenomenon and supports its application as a pharmaceutical excipient.CS enhances oral drug absorption through various mechanisms,such as interaction with the intestinal mucosa,tight junction modulation,inhibition of efflux transporters,enzyme inhibition,solubility and stability enhancement,and complexation.On the other side,CS exhibits the ability to inhibit the absorption of certain drugs by adsorbing to lipids and sterols,modulating bile acids and gut microbiota,altering drug-cell interaction at the polar interface,and mucus-mediated entrapment and interference.Future potential pharmaceutical research in this field includes elucidating the underneath absorption relevant mechanisms,rational use in formulations as excipient,exploring functional CS derivatives,and developing CS-based drug delivery systems.This comprehensive review highlights CS's versatile and significant role in enhancing and inhibiting oral drug absorption,providing insights into the complexities of drug delivery and the potential of CS to improve therapeutic outcomes.
基金Chulalongkorn University and the National Science and Technology Development Agency(NSTDA)for providing the Chulalongkorn University-NSTDA Doctoral Scholarship,which funded this articlesupport from the 90~(th)Anniversary of Chulalongkorn University Scholarship under the Ratchadaphisek Somphot Endowment Fund。
文摘In recent years,the addition of probiotics into non-dairy beverages has gained popularity.Probiotics offer a wider range of options for individuals who are sensitive to dairy products.Incorporating probiotics into widely consumed beverages like carbonated soft drinks poses a notable challenge due to the detrimental impact of acidic pH.Herein,results demonstrate that chitosan-coated alginate/gellan gum microcapsules can enhance the viability of probiotics within carbonated soft drinks.The probiotics,Lactobacillus casei,are encapsulated in microcapsules and exposed to Pepsi,Fanta Strawberry,Sprite,and A&W Root Beer under 4 and 25℃for 60 days and simulated gastrointestinal tract.Microcapsules greatly improve the viability of adding probiotics in different beverages under simulated gastrointestinal tract.The probiotics had a gradual release from microcapsules,reaching maximum release within initial 2 h of simulated intestinal phase.During 4℃storage compared to storage at 25℃,it was found that the number of surviving cells is more than the recommended minimum(10^(6)CFU/g)at the end of the storage.The pH and soluble solids content of beverages containing microcapsules also signify little change.This work shows that the chitosan-coated alginate/gellan microcapsules have the potential to be used as protective microcapsules for probiotics in carbonated soft drinks.
文摘Proton exchange membrane(PEM)is an integral component in fuel cells which enables proton transport for efficient energy conversion.Sulfonated Polyether Ether Ketone(SPEEK)has emerged as a cost-effective option with non-fluorinated aromatic backbones for Proton Exchange Membrane Fuel Cell(PEMFC)applications,even though it exhibits lower proton conductivity compared to Nafion.This work aims to study the influence of Sulfonated Chitosan(SCS)concentrations on proton conductivity of SPEEK-based PEM at room temperature.SPEEK was synthesized using a sulfonation process with concentrated sulfuric acid at room temperature.SCS was synthesized via reflux of CS and 1.2 M H2SO4 with a ratio of 1:35(w/v)at 90℃ for 30 min.The composite membranes of SPEEK-SCS were formed with four different SCS concentrations,using the solution castingmethod,andDimethyl Sulfoxide(DMSO)was used as a solvent.The composite membranes synthesized include pure SPEEK(S0),SPEEK with 1%SCS(S1),SPEEK with 2%SCS(S2),and SPEEK with 3%SCS(S3).Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),water uptake,degree of swelling,Ionic exchange capacity(IEC)with Electrochemical impedance spectroscopy(EIS)were used to characterize the composite membranes in terms of composition,crystallinity,water absorption,dimensional changes,number of exchangeable ions in membranes,and proton conductivity,respectively.Notably,S3 had the highest water uptake and the lowest degree of swelling.S2 had the highest proton conductivity among the SPEEK-SCS composite membranes at room temperature with 3.44×10^(−2) Scm^(-1).
基金supported by Doctoral Scientific Fund Project of Southwest University of Science and Technology(20zx7130)Seawater Uranium Extraction Innovation and Development Fund Project(China National Nuclear Corporation)(CNNCCXLM-202215)。
文摘Many adsorbents have been developed for uranium recovery to ensure global energy and environmental security.However,most reported adsorbents involve complex preparation process and rely heavily on petrochemical feedstocks,which undoubtedly increases carbon emissions from production in the nuclear industry.Here,a biomass aerogel(CS-BT)is prepared by the facile cross-linking of chitosan and bayberry tannins with glutaraldehyde.U(Ⅵ)can be adsorbed by hydroxyl groups on CS-BT aerogel via chelation,and the maximum adsorption capacity of the obtained aerogel to U(Ⅵ)is 140 mg·g^(-1)and the removal rate reaches up to 99%(at 298.15 K,pH=5.0).The pseudo-second-order kinetics model and Freundlich model can better match the adsorption process of CS-BT aerogel,implying that its adsorption is a chemical adsorption process dominated by multilayer adsorption.The thermodynamic results show that the adsorption process of U(Ⅵ)by CS-BT aerogel is spontaneous and exothermic.Hence,our biomass aerogel can effectively extract uranium from water,contributing to the sustainable development of the nuclear industry.
文摘The cultivation of Soledad pepper(Capsicum annuum L.)is essential in Oaxaca and Veracruz,but it faces issues with pests and diseases,which affect yield and cause economic losses.To mitigate these impacts,farmers have started using biostimulants such as chitosan and plant growth promoting bacteria instead of agrochemicals due to their environmental and health benefits.This study evaluated the effect of Bacillus subtilis and chitosan,both individually and combined,on the growth,yield,and fruit quality of Soledad pepper under greenhouse conditions.Four treatments were applied at different stages of the crop cycle:Q(Chitosan),BS(Bacillus subtilis),Q+BS(Chitosan+Bacillus subtilis),and T(Control).The results showed that the combination of chitosan and Bacillus subtilis significantly improved plant growth,especially in height and stem diameter.The chitosan treatment produced the highest number of fruits and plant weight,while the combination of chitosan and Bacillus subtilis enhanced fruit quality,increasing characteristics such as size,weight,pericarp thickness,and physicochemical parameters,notably in brix degrees,citric acid percentage,and pH,outperforming the individual treatments and the control.
基金supported by the National Natural Science Foundation of China,Nos. 32260196 (to JY), 81860646 (to ZY) and 31860274 (to JY)a grant from Yunnan Department of Science and Technology,Nos. 202101AT070251 (to JY), 202201AS070084 (to ZY), 202301AY070001-239 (to JY), 202101AZ070001-012, and 2019FI016 (to ZY)。
文摘Studies have shown that chitosan protects against neurodegenerative diseases. However, the precise mechanism remains poorly understood. In this study, we administered chitosan intragastrically to an MPTP-induced mouse model of Parkinson's disease and found that it effectively reduced dopamine neuron injury, neurotransmitter dopamine release, and motor symptoms. These neuroprotective effects of chitosan were related to bacterial metabolites, specifically shortchain fatty acids, and chitosan administration altered intestinal microbial diversity and decreased short-chain fatty acid production in the gut. Furthermore, chitosan effectively reduced damage to the intestinal barrier and the blood–brain barrier. Finally, we demonstrated that chitosan improved intestinal barrier function and alleviated inflammation in both the peripheral nervous system and the central nervous system by reducing acetate levels. Based on these findings, we suggest a molecular mechanism by which chitosan decreases inflammation through reducing acetate levels and repairing the intestinal and blood–brain barriers, thereby alleviating symptoms of Parkinson's disease.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF1001500)the National Natural Science Foundation of China(Grant No.32102233 to G.S.,Grant No.31971217 to H.Y.)+3 种基金the China Postdoctoral Science Foundation(Grant No.2024T170421,G.S.)the Jiangsu Funding Program for Excellent Postdoctoral Talent(Grant No.2023ZB236,G.S.)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20231129,G.S.)the Key Research and Development Program of Guangdong Province(Grant No.2022B0202080004)。
文摘Chitin and its deacetylated derivative chitosan are the major components of fungal cell walls and are recognized by plant pattern-recognition receptors(PRRs)as pathogen-associated molecular patterns that induce innate immunity.Recognition of chitin oligosaccharide(CTOS)in Arabidopsis(Arabidopsis thaliana)and rice(Oryza sativa)requires the membrane-localized lysin-motif(LysM)-domain-containing receptors AtLYK5and OsCEBiP,respectively.However,the mechanism underlying chitosan oligosaccharide(CSOS)-induced plant immunity remains unclear.In this study,we determined that CTOS and CSOS trigger immune responses and boost disease resistance in soybean(Glycine max)through the LysM-domain-containing protein GmNRF5a and its co-receptor GmCERK1.Surprisingly,both GmNFR5a and GmCERK1 bind directly to CTOS and CSOS,with distinct binding sites.The receptor-like kinase GmCAK1 acts downstream of GmCERK1 and is essential for CTOS/CSOSmediated immune activation.Overall,these findings uncovered how soybean plants respond to CSOS and initiate immune signaling,demonstrating that soybean exploits shared immune sectors to transduce immune signals triggered by CTOS/CSOS,paving the way for the development of disease-resistant crops with broad-spectrum resistance.
文摘The potent antibacterial activity of silver nanoparticles is primarily attributed to the release of silver ions,which disrupt cell membranes and inactivate essential enzymes through Ag−S bonding formation.[Objective]To explore silver ion immobilization to minimize silver release.[Methods]A macrocyclic cryptand with nitrogen bridgeheads was prepared and subsequently chelated with silver ions to produce Cage silver(I),which was then coordinated with different ratios of sulfonated chitosan(SCS)to form SCS/Cage Ag(I)complexes(SCA1,SCA2,and SCA3).The antioxidant activities of the complexes were assessed by reducing power and 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical and hydrogen peroxide scavenging assays.The antibacterial activities of the complexes were evaluated based on the minimum inhibitory concentrations(MICs)and minimum bactericidal concentrations(MBCs)against Staphylococcus aureus ATCC 6538 and Escherichia coli O157:H7 and the inhibition rate on biofilm formation.[Results]Cage silver(I)exhibited strong antibacterial activity,with the MIC of 0.015 mg/mL and MBC of 0.031 mg/mL against S.aureus ATCC 6538,and the MIC of 0.031 mg/mL and MBC of 0.120 mg/mL against E.coli O157:H7.Significant antioxidant properties of Cage silver(I)were also observed,as demonstrated by the DPPH free radical scavenging rates of 42.2%and 53.1%at 326 nm and 517 nm,respectively.Cage silver(I)exhibited the highest antibacterial and antioxidant activities,followed by SCA1,SCA2,SCA3,and SCS,because the content of silver ions in Cage silver(I)was 10-fold higher than that in SCA1.The antibacterial and antioxidant activities of SCA1 were better than those of Cage silver(I),which further indicated that the sulfonic groups of SCS may intensely coordinate with silver ions to exert synergistic effects.[Conclusion]Combining the merits of silver ions and SCS improves the bioavailability of the agent at microbicidal concentrations,minimizes the accumulation in the environment,and reduces treatment costs.The method developed herein offers a sustainable approach to enhance microbial control while minimizing the impact on the environment.
基金supported in part by the National Natural Science Foundation of China(12174366)Fundamental Re-search Funds for the Central Universities(WK3450000005)the Anhui Provincial Natural Science Foundation(2108085MC93).
文摘The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.
文摘The ability to replicate the microenvironment of the human body through the fabrication of scaffolds is a significant achievement in the biomedical field.However,the search for the ideal scaffold is still in its infancy and there are significant challenges to overcome.In the modern era,the scientific community is increasingly turned to natural substances due to their superior biological ability,lower cost,biodegradability,and lower toxicity than synthetic lab-made products.Chitosan is a well-known polysaccharide that has recently garnered a high amount of attention for its biological activities,especially in 3D bone tissue engineering.Chitosan closely matches the native tissues and thus stands out as a popular candidate for bioprinting.This review focuses on the potential of chitosan-based scaffolds for advancements and the drawbacks in bone treatment.Chitosan-based nanocomposites have exhibited strong mechanical strength,water-trapping ability,cellular interaction,and biodegradability.Chitosan derivatives have also encouraged and provided different routes for treatment and enhanced biological activities.3D tailored bioprinting has opened new doors for designing and manufacturing scaffolds with biological,mechanical,and topographical properties.
文摘Electrospinning has gained significant importance across various fields,including biomedicine,filtration,and packaging due to the control it provides over the properties of the resulting materials,such as fiber diameter and membrane thickness.Chitosan is a biopolymer that can be utilized with both natural and synthetic copolymers,owing to its therapeutic potential,biocompatibility,and biodegradability.However,producing electrospun chitosan is challenging due to its high solution viscosity,which often results in the formation of beads instead of uniform fibers.To address this issue,the spinnability of chitosan is significantly enhanced,and the production of continuous nanofibers is facilitated by combining it with polymers such as polyethylene oxide(PEO)in suitable ratios.These chitosan–PEO nanofibers are primarily used in biomedical applications,including wound healing,drug delivery systems,and tissue engineering scaffolds.Additionally,they have shown promise in water treatment,filtration membranes,and packaging.Among all the nanofiber mats,chitosan/PEO-AC had the smallest fiber diameter(83±12.5 nm),chitosan/PEO_45S5 had the highest tensile strength(1611±678 MPa).This comprehensive review highlights recent advancements,ongoing challenges,and future directions in the electrospinning of chitosan-based fibers assisted by PEO.
基金MOHE (FRGS/1/2023/STG05/UITM/01/3) for funding support
文摘CRISPR-Cas system permanently deletes any harmful gene-of-interest to combat cancer growth.Chitosan(CS)is a potential cancer therapeutic that mediates via PI3K/Akt/mTOR,MAPK and NF-kβsignaling pathway modulation.CS and its covalent derivatives have been designed as nanocarrier of CRISPR-Cas9 alone(plasmid or ribonucleoprotein)or in combination with chemical drug for cancer treatment.The nanocarrier was functionalized with polyethylene glycol(PEG),targeting ligand,cell penetrating ligand and its inherent positive zeta potential to mitigate premature clearance and particulate aggregation,and promote cancer cell/nucleus targeting and permeabilization to enable CRISPR-Cas9 acting on the host DNA.Different physicochemical attributes are required for the CS-based nanocarrier to survive from the administration site,through the systemic circulation-extracellular matrix-mucus-mucosa axis,to the nucleus target.CRISPR-Cas9 delivery is met with heterogeneous uptake by the cancer cells.Choice of excipients such as targeting ligand and PEG may be inappropriate due to lacking overexpressed cancer receptor or availability of excessive metabolizing enzyme and immunoglobulin that defies the survival and action of these excipients rendering nanocarrier fails to reach the target site.Cancer omics analysis should be implied to select excipients which meet the pathophysiological needs,and chitosan nanocarrier with a“transformative physicochemical behavior”is essential to succeed CRISPR-Cas9 delivery.
基金supported financially by the NSFC(Nos.62075098 and 62071119)the National Key Research and Development Program of China(Nos.2017YFA0205301 and 2018YFC1602905)。
文摘MicroRNAs(miRNAs)are abundant in the brain and mounting evidence suggests their involvement in the critical processes such as neurodevelopment,synaptic plasticity,and the development of neurodegenerative diseases.Thus,miRNAs may be promising therapeutic drugs for the treatment of neurodegenerative disorders.However,naked miRNAs are not able to enter cells directly,especially brain cells.Therefore,suitable carriers for safe and efficient miRNA delivery to brain cells are of great importance.Chitosan nanoparticles,with the excellent properties such as good compatibility and brilliant degradability,may act as a promising carrier for miRNA drug delivery.In this study,chitosan nanoparticles were prepared and their properties such as particle size,zeta potential and encapsulation efficiency were optimized to encapsulate miRNAs.The delivery efficiency of miRNA-loaded nanoparticles was then evaluated in both neuronal and microglia cells.The results demonstrated chitosan nanoparticles encapsulated miRNAs efficiently and showed excellent sustained releasing in vitro.Moreover,chitosan nanoparticles delivered miRNA to both neurons and microglia with very low toxicity and high efficiency.In conclusion,chitosan nanoparticles are promising carriers for the delivery of miRNAs to brain cells,which may be used for the early intervention and treatment of neurodegenerative disorders.
文摘Objective:To develop chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms and verify their antibacterial performance through animal experiments.Methods:Chitosan,silver nitrate,glacial acetic acid,and other chemical reagents were used to synthesize chitosan-silver nanoparticles.The characterization,minimum inhibitory concentration,and biofilm inhibition rate of the chitosan-silver nanoparticles were tested.A total of 40 SD rats were randomly divided into four groups.After routine adaptive feeding,the control group received intraperitoneal injection of normal saline;the model group received intraperitoneal injection of Pseudomonas aeruginosa suspension;the positive group received intraperitoneal injection of Pseudomonas aeruginosa suspension mixed with ampicillin at a volume ratio of 1∶1;the observation group received intraperitoneal injection of Pseudomonas aeruginosa suspension mixed with chitosan-silver nanoparticles(at minimum inhibitory concentration)at a volume ratio of 1∶1.Bacterial load,inflammatory factors,and liver and kidney function indicators in tissues were observed and compared among the four groups on the 3^(rd)day after treatment.Results:When the concentration of chitosansilver nanoparticles reached 8μg/mL or above,the OD value of the experimental wells was close to that of the control wells,indicating that 8μg/mL was the minimum inhibitory concentration of the chitosan-silver nanoparticles;at concentrations of 8μg/mL or above,the biofilm inhibition rate was greater than 80%.The bacterial load in the observation group was significantly lower than that in the model and positive groups(P<0.05).The expression levels of interleukin-6,interferon-γ,and tumor necrosis factor-αin the observation group were significantly lower than those in the model and positive groups(P<0.05).There were no statistically significant differences in alanine aminotransferase,aspartate aminotransferase,blood urea nitrogen,and creatinine levels among the four groups(P>0.05).Conclusion:The chitosan-silver nanoparticles targeting Pseudomonas aeruginosa biofilms constructed in this study exhibit good antibacterial effects against Pseudomonas aeruginosa and have good safety.
基金supported by the Research Council of Tarbiat Modares University and the Iran National Science Foundation(INSF)(Grant Number:4043897).
文摘This study aimed to assess the therapeutic potential of nisin,5-fluorouracil(5FU)and selenium encapsulated in folate-conjugated thiolated chitosan nanoparticles(N/5FU/Se@FTCsNPs),combined with a probiotic cocktail of Lactobacillus acidophilus and Bifidobacterium bifidum,against colorectal cancer(CRC).The nanoparticles(277 nm,+9.2 mV)exhibited high drug loading efficiencies(5FU:89.11%,nisin:70.68%)and pH-responsive release,with minimal drug release under gastric conditions and∼60.7%release at colonic pH,facilitating targeted delivery.The formulation remained stable for over 40 d at−20°C and 4°C,demonstrating excellent biocompatibility(<2%hemolysis)and exhibiting strong mucoadhesive and mucus-penetrating abilities.In vitro,N/5FU/Se@FTCsNPs selectively targeted CT26 colon cancer cells(IC5n:1.57μg/ml)with minimal effects on healthy cells,enhanced cellular uptake,and induced ROS-mediated apoptosis.In vivo,oral administration-especially with probiotics-significantly reduced tumor volume,improved survival rates and alleviated chemotherapy-related side effects such as diarrhea and weight loss.Biodistribution studies confirmed increased tumor targeting and decreased off-target exposure.Mechanistically,the treatment downregulated oncogenes and inflammatory markers(2-to 12.5-fold),includingβ-catenin,mTOR,COX-2 and VEGF-α,while upregulating tumor suppressors and protective genes(4 to 14.8 fold),such as PTEN,CASP9 and Mucin 2(P<0.0001).This indicates inhibition of proliferation,metastasis,inflammation,and angiogenesis,along with improved gut barrier function.Cytokine profiling and histological analysis further confirmed reduced systemic inflammation and maintained hematological safety.These findings highlight N/5FU/Se@FTCsNPs combined with probiotics as a promising,safe and effective oral therapy for CRC,leveraging microbiota modulation and targeted delivery.
