Preparation Of Micro-nano Modified Thermosensitive Hydrogel And Study On Its Drug Release Property

Hydrogels have been widely used in the field of biomedicine,especially for drug loading and release,due to their good hydrophilicity,flexibility and biocompatibility.Hydrogels prepared from traditional materials have disadvantages such as poor mechanical properties,slow environmental response,low drug loading,and unsatisfied drug release properties,which greatly limits their large-scale application.In order to improve the mechanical properties and environmental response of hydrogels,we used carbon nanotubes and chitosan derivatives to modify the hydrogel,and on the basis of the original advantages of the hydrogel,we prepared a new type of micro-nano modified composite hydrogel material.In addition,we have introduced a temperature sensitive monomer N,N-diethylacrylamide（DEA）during the preparation of the hydrogel,which can achieve controllable drug release and enhanced drug utilization caused by temperature difference.The specific research contents are as follows:（1）DEA-NHMAA-CNT/CCS thermosensitive hydrogels were prepared by crosslinking polymerization of DEA,hydrophilic monomer hydroxymethyl acrylamide（NHMAA）and carbon nanotubes modified by carboxyl chitosan（CNT/CCS）.The composition and structure of the hydrogel were analyzed through a series of characterizations.The mechanical properties,drug release ability and antibacterial activity were also studied.The results show that low critical phase transition temperature（LCST）of the DEA-NHMAA-CNT/CCS thermosensitive hydrogel is near the physiological temperature of the human body.With the addition of CNT/CCS,the pore size of the hydrogel becomes larger,the temperature sensitivity increases,the drug-carrying capacity increases,and it has a good photothermal effect.In addition,the thermosensitive hydrogel(DN₂₅C₁)containing 1%CNT/CCS shows the best compression performance,with a maximum compressive strength of 0.176 MPa.DN₂₅C₁ hydrogel has a good sustained release behavior for the model drug ciprofloxacin hydrochloride at different temperatures.The cumulative release rate of the drug at 25℃,37℃and 40℃reached 75.17%,82.68%and 90.24%,respectively,showing good antibacterial activity.（2）DEA-QCGM-CNT thermosensitive hydrogels were prepared by cross-linking copolymerization of vinyl quaternary ammonium chitosan（QCGM）,carbon nanotubes and DEA.The structure of DEA-QCGM-CNT hydrogels was analyzed by a series of characterization methods.The mechanical properties,swelling properties,drug release ability and antibacterial activity of the hydrogels were also studied.The results showed that the swelling and mechanical properties of the hydrogels could be improved by adding CNT and QCGM.The LCST of hydrogels could be adjusted by controlling the ratio of DEA to QCGM.The DEA-QCGM-CNT hydrogel shows good temperature sensitivity,photothermal effect and drug loading capacity.The drug loading is directly proportional to the drug concentration,performing a good drug release behavior and antibacterial effect at different concentration and temperature.