Design Of Drug Delivery System Based On Guanosine Supramolecular Hydrogels

Rational design of drug delivery and controlled release system can improve drug efficacy and reduce toxic.The application of stimulus-responsive supramolecular materials is effective in drug encapsulation and controlled release.Guanosine-based supramolecular hydrogels are widely used in biomedical materials because of their responsiveness to stimuli.In this paper,it was first discovered that guanosine reacts with 2-formylphenylboric acid under alkaline conditions to form a[G-FPBA]4·K+hydrogel.It was found that only 2-formylbenzoboric acid in potassium hydroxide solution could form a stable hydrogel.By changing the alkali metal ions introduced into the system,it was found that only by introducing potassium ions could the system form a stable hydrogel,when introducing sodium ions,lithium ions and cesium ions,the system was solution state.The sol-gel transformation was realized by using the response of hydrogel to pH and metal ions.Through XRD,CD,FTTR,TEM,SEM,AFM and POM test,analyzed the composition structure and morphology characterization,proves that guanosine form G-quartet structure by hydrogen bonding,through the π-π stacking interaction to form nano fiber,nano fiber further closely intertwined to form three dimensional network and supramolecular hydrogel.The drug release behavior of hydrogels loaded with drugs in different environments was studied by UV-vis spectrophotometry.It was found that the stimulation response of hydrogels to pH and ROS species could destroy the three-dimensional network structure of hydrogels and realize the controlled release of drugs.In addition to physical inclusion,borate bonds are also used in this paper to covalently bind drugs with cineo-dihydroxyl structure to 1,4-phenyldiboric acid and form[G-BDB-D]4·K+ supramolecular hydrogels under alkaline conditions.The hydrogels are also sensitive to pH and metal ions and can achieve sol-gel transformation.The structure and morphology of hydrogels were characterized and the drug release performance of hydrogels was analyzed.The results of enema in rats show that the hydrogel has a good prospect in drug delivery and controlled release.