Preparation Properties And Application Basis Of Collagen Hydrogel

Skin wounds affect millions of patients worldwide and pose an increasingly serious burden on healthcare systems.Therefore,the development of safe and effective wound dressings has been a continuous goal.Collagen hydrogel has attracted much attention due to its hydrophilic three-dimensional network structure similar to the extracellular matrix.It can provide a breathable and moist environment for wounds and optimize the inflammatory microenvironment of wounds,making it one of the most competitive candidates in the field of wound dressings.In this thesis,a collagen（Col）/N-lauroyl-O-carboxymethyl chitosan（LA-CMCh）hydrogel was prepared using genipin（Gp）as a crosslinking agent.With the increase of the concentration of captopril,the intermolecular interactions between collagen and captopril increase,making the hydrogel more stable and better able to resist external forces.In addition,the increase in captopril concentration also leads to an increase in the crosslinking degree of the hydrogel,making the microstructure of the hydrogel more compact.The addition of LA-CMCh enhances the function of hydrogen bonds in the hydrogel,effectively improving its mechanical properties.Col/Gp/LA-CMCh hydrogel can meet the compression requirements and can be used as a delivery system for wound treatment.Cell toxicity tests have shown that Col/Gp/LA-CMCh hydrogel can promote cell proliferation,making it safe to use as a wound dressing.The initial release rate of levofloxacin hydrochloride is fast,and the release time is long,indicating that the hydrogel has great potential for application in wound dressing for drug delivery.In this thesis,a hydrolyzed collagen（Gel）/carboxymethyl chitosan（CMCh）/aloe composite hydrogel was prepared using glutaraldehyde as a crosslinking agent.The electrostatic interactions and hydrogen bonding between hydrolyzed collagen and CMCh hindered their ability to refold into triple helical structures,resulting in a decrease in the strength of the hydrogel.The hydrogel showed slight shear thinning behavior,which can promote its application in skin care.As the content of CMCh increased,the plasticizing effect of the hydrogel decreased,while its thermal behavior remained unchanged and its thermal conductivity increased.The prepared hydrogel had a uniform pore size,but the addition of CMCh and aloe reduced the pore size and increased the thickness of the pore walls.The introduction of aloe molecules into the gel matrix greatly enhanced the mechanical properties of the hydrogel.The addition of aloe also endowed the hydrogel with good antibacterial activity against Escherichia coli and Staphylococcus aureus.The cytotoxicity test co-cultured with HFF-1 cells showed that the hydrogel had good biocompatibility.The rapid release and sustained release behavior of levofloxacin hydrochloride encapsulated in the hydrogel indicate that the Gel/CMCh/aloe hydrogel constructed in this study has great potential in the field of antibacterial wound dressings.This thesis successfully prepared Gel/PAM double network hydrogels with varying mass ratios using both physical cross-linked hydrolyzed collagen and covalently cross-linked polyacrylamide（PAM）as the first and second networks,respectively.The rheological properties indicated that the storage modulus（G’）of the Gel/PAM double network hydrogel was much higher than that of a single hydrolyzed collagen or polyacrylamide gel.The Gel/PAM hydrogel network was chemically and physically cross-linked through the hydrolyzed collagen and polyacrylamide chains,increasing the distance between network connections and ultimately resulting in high elasticity.The structure of the Gel/PAM hydrogel became denser with an increase in acrylamide content,causing more physical entanglement between the molecules and a slight decrease in swelling ratio.At a mass ratio of hydrolyzed collagen to acrylamide of 1:5,the system exhibited strong mechanical properties,including high tensile strength（111 k Pa）and elongation at break（678.25%）.Due to its high mechanical strength,this hydrogel has potential applications as a wound dressing.This thesis investigated the effects of chitosan derivatives with different electrical properties（carboxymethyl chitosan,hydroxypropyltrimethyl ammonium chloride chitosan,and zwitterionic chitosan）and cellulose nanomaterials（cellulose nanofibers and nanocrystalline cellulose）on the gelation of carboxymethyl cellulose（CMC）solutions under different mass fractions and temperature conditions,and their interactions were studied using rheological methods.The results showed that HACC,HTCMCh,and CNF all had thickening effects on CMC solutions.The strong electrostatic interaction between10%HACC and CMC eliminated the Newtonian plateau of the CMC solution,and the CMC/HACC_10%solution maintained a considerable apparent viscosity even with an increase in temperature.