Construction And Application Of Hydrogels Based On β-cyclodextrin

The hydrogel is well known as soft polymer materials with high water content and high biocompatibility,which has been widely used in the fields of biomedical engineering and drug sustained-release.A polymerizable modified cyclodextrin molecule with the cavity size characteristics is synthesized and introduced into gelatin hydrogels to improve the drug release performance and slow-release ability.On this basis,the modified polymerizable azobenzene monomer with the photosensitive property is introduced to prepare the self-healing hydrogel based on the host-guest interaction.These materials have potential applications in tissue repair,flexible sensors,and other fields.First of all,β-cyclodextrin（β-CDA₂）is prepared by a nucleophilic substitution reaction.The product is characterized and certified by FT-IR,¹H-NMR,and potassium bromide potassium bromate addition method.The acylation yield reaches up to 77%by optimizing of reaction condition.A new series of PCD_XGM hydrogels is prepared by UV-initiated radical polymerization with gelatin methacryloyl（Gel MA）usingβ-CDA₂ as a crosslinking agent.Methyl orange（MO）is used as a drug molecule model to investigate the adsorption and release of PCD_XGM hydrogels in vitro.The effects of the dosage ofβ-CDA₂,temperature,and p H value of the medium on the release kinetics of methyl orange are studied.The results show that the MO adsorption capacity of PCD_XGM hydrogels increases with the addition ofβ-CDA₂.The adsorption capacity of PCD₉GM hydrogel is as high as 33.3 mg/g,which is 5.2 times that of PCD₀GM hydrogel.The MO release kinetics test results show that the MO release efficiency and release time are significantly improved afterβ-CDA₂ is added to PCD_XGM hydrogel.PCD₉GM hydrogel shows the best slow-release behavior under three physiological conditions（T=37℃,p H=7.2;T=40℃,p H=7.2 and T=37℃,p H=1.5）.The release percentage of PCD₀GM hydrogel is more than 80%within 6 h,and the sustained release time is less than 12 h.However,PCD₉GM hydrogel can only release less than 50%methyl orange after 12 h,and the effective release behavior can last for more than 96 h.The obtained material exhibits important research value in the field of drug delivery and sustained release.In addition,the acrylate azobenzene（a Azo）monomer with the activated group is synthesized.The monomer can be encapsulated byβ-cyclodextrin.Then,the host-guest supramolecular（CD/Azo）is prepared by physical inclusion of a Azo andβ-CDA₂.The poly（β-cyclodextrin/azobenzene）-acrylamide supramolecular hydrogels（P（CD/Azo-AM））are prepared with acrylamide by radical thermal polymerization using CD/Azo as a cross-linking agent.The mechanical properties and self-repair properties are studied.The results show that the mechanical properties of P（CD/Azo-AM）hydrogel increase first and then decrease with the increasing of CD/Azo content.At the same time,P（CD/Azo-AM）hydrogels also have self-healing properties by increasing host-guest supramolecular content.The self-repairing property of P（CD/Azo-AM）hydrogel is the best when the self-repairing time is 3 h and the CD/Azo content is 4 mmol/L.Compared with the hydrogel without CD/Azo,the breaking strength of P（CD/Azo-AM）hydrogel increase by 620%,and the elongation at break increase by 200%.In conclusion,P（CD/Azo-AM）hydrogels show a potential application value in photosensitive sensors,drug encapsulation,and tissue repair.