Protein-polymer hybrids consisting of protein and natural polymers or synthetic polymers exhibit superior properties to un- modified proteins, generating a high demand for these materials in the fields of medicine, bi...Protein-polymer hybrids consisting of protein and natural polymers or synthetic polymers exhibit superior properties to un- modified proteins, generating a high demand for these materials in the fields of medicine, biotechnology, and nanotechnology. Herein, protein-polysaccharide hybrids were fabricated via the formation of an amide bond between bovine serum albumin （BSA） and chitosan （CS） using N-ethyl-N-（3-dimethylaminopropyl） carbodiimide hydrochloride （EDC） as the couple reagent. FTIR spectrum reveals that the carboxyl group of BSA conjugated with the amino group of chitosan backbone. The molecular weight of BSA-CS hybrids was identified by matrix-associated laser desorption ionization time of flight mass spectra （MALDI-TOF MS） and sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）. The maximum number of chitosan chains binding to each BSA molecule was estimated as 6, and the optimal number was estimated as 2. In addition, the secondary structure and surface property of BSA were dependent upon the number of polymer conjugating on protein. The secondary structure of BSA was not significantly changed, if a few chitosans were coupled with BSA. By further increasing the molar ratio of chitosan to BSA, the secondary structure of BSA was markedly damaged. The surface＇s negative charges of modified BSA also decreased. The result of native polyaerylamide gel electrophoresis （native-PAGE） also demonstrated the changes in surface charges and molecular weight of BSA-CS hybrids.展开更多
Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bendi...Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bending strength and bending modulus of CS rods need to be improved to match the commercially available devices used for bone fracture internal fixation.In this research,CS rods were reinforced effectively through cross-linking reaction by using glutaraldehyde as the coupling reagent.Schiff’s base was detected by FTIR due to the chemical reaction between amino groups and aldehyde groups.Crystal plane space of CS rods became small during the formation of network structure.Microstructure was observed by SEM,indicating that layer-by-layer structure became much tighter after cross-linking reaction,and cracks in one layer turned around when they reached another layer to absorb energy.Bending strength and bending modulus of cross-linked CS rods could reach 186.3 MPa and 5.17 GPa,respectively.Compared with uncross-linked CS rods,they are increased by 101.6% and 26.1%,respectively.As a result,mechanical properties of CS rods are equivalent to the commercially available biodegradable devices.CS rods with excellent mechanical properties are a good candidate for bone fracture internal fixation.展开更多
Chitosan(CS)is the only natural alkaline polysaccharide originated from deacetylation of chitin that is the main component of shell from marine organisms.It has great potential medical application due to its broad-spe...Chitosan(CS)is the only natural alkaline polysaccharide originated from deacetylation of chitin that is the main component of shell from marine organisms.It has great potential medical application due to its broad-spectrum antimicrobial activity and good water solubility originated from its protonated amino groups under acidic condition and abundant hydroxyl groups.However,unprotonated NH_(2)group of CS leads to its poor solubility under physiological condition and limits its diverse applications.Therefore,it is highly necessary to summarize the modification strategies of CS derivatives systematically to help researchers select the most appropriate strategies for their specific applications.Herein,we have summarized the modification strategies of CS derivatives for improving their antimicrobial activity,water solubility,biocompatibility,and mechanical property by chemical reaction and physical integration.And then we have reviewed the CS derivatives in hydrogels,nanoparticles,or coatings for medical application in wound dressing,drug delivery,medical implant.Last but not the least,we have put forward the future perspectives of deep studies about structure-activity relationship and clinical applications of CS derivatives.展开更多
基金supported by the National Natural Science Foundation of China (21164003,20964002)the Gansu Sci & Techn Support Project(1011GKCA017)+2 种基金the Fundamental Res. Funds Univ. Gansu Province(2010-176)Lanzhou Science Technology Bureau (2009-1-14)NWNU-kjcxgc-03-63
文摘Protein-polymer hybrids consisting of protein and natural polymers or synthetic polymers exhibit superior properties to un- modified proteins, generating a high demand for these materials in the fields of medicine, biotechnology, and nanotechnology. Herein, protein-polysaccharide hybrids were fabricated via the formation of an amide bond between bovine serum albumin （BSA） and chitosan （CS） using N-ethyl-N-（3-dimethylaminopropyl） carbodiimide hydrochloride （EDC） as the couple reagent. FTIR spectrum reveals that the carboxyl group of BSA conjugated with the amino group of chitosan backbone. The molecular weight of BSA-CS hybrids was identified by matrix-associated laser desorption ionization time of flight mass spectra （MALDI-TOF MS） and sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）. The maximum number of chitosan chains binding to each BSA molecule was estimated as 6, and the optimal number was estimated as 2. In addition, the secondary structure and surface property of BSA were dependent upon the number of polymer conjugating on protein. The secondary structure of BSA was not significantly changed, if a few chitosans were coupled with BSA. By further increasing the molar ratio of chitosan to BSA, the secondary structure of BSA was markedly damaged. The surface＇s negative charges of modified BSA also decreased. The result of native polyaerylamide gel electrophoresis （native-PAGE） also demonstrated the changes in surface charges and molecular weight of BSA-CS hybrids.
基金supported by the National Natural Science Foundation of China (50333020 & 50773070)National Basic Research Program of China ((973 Program,2009CB930104)+1 种基金China Postdoctoral Science Foundation (20100480085)Grand Science and Technology Special Project of Zhejiang Province (2008C11087)
文摘Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bending strength and bending modulus of CS rods need to be improved to match the commercially available devices used for bone fracture internal fixation.In this research,CS rods were reinforced effectively through cross-linking reaction by using glutaraldehyde as the coupling reagent.Schiff’s base was detected by FTIR due to the chemical reaction between amino groups and aldehyde groups.Crystal plane space of CS rods became small during the formation of network structure.Microstructure was observed by SEM,indicating that layer-by-layer structure became much tighter after cross-linking reaction,and cracks in one layer turned around when they reached another layer to absorb energy.Bending strength and bending modulus of cross-linked CS rods could reach 186.3 MPa and 5.17 GPa,respectively.Compared with uncross-linked CS rods,they are increased by 101.6% and 26.1%,respectively.As a result,mechanical properties of CS rods are equivalent to the commercially available biodegradable devices.CS rods with excellent mechanical properties are a good candidate for bone fracture internal fixation.
基金financially supported by the National Natural Science Foundation of China(Nos.51573097 and 51773117)。
文摘Chitosan(CS)is the only natural alkaline polysaccharide originated from deacetylation of chitin that is the main component of shell from marine organisms.It has great potential medical application due to its broad-spectrum antimicrobial activity and good water solubility originated from its protonated amino groups under acidic condition and abundant hydroxyl groups.However,unprotonated NH_(2)group of CS leads to its poor solubility under physiological condition and limits its diverse applications.Therefore,it is highly necessary to summarize the modification strategies of CS derivatives systematically to help researchers select the most appropriate strategies for their specific applications.Herein,we have summarized the modification strategies of CS derivatives for improving their antimicrobial activity,water solubility,biocompatibility,and mechanical property by chemical reaction and physical integration.And then we have reviewed the CS derivatives in hydrogels,nanoparticles,or coatings for medical application in wound dressing,drug delivery,medical implant.Last but not the least,we have put forward the future perspectives of deep studies about structure-activity relationship and clinical applications of CS derivatives.
