Thiol modified chitosan-silica nanohybrid for antibacterial, antioxidant and drug delivery application

Chitosan exhibits great versatility in various biomedical fields and mesoporous silica nanoparticles have emerged as an interesting material in biomedical areas owing to their outstanding physio-chemical properties. The combination of inorganic silica and organic polymer such as chitosan, make them suitable for a wide range of biomedical applications. Here, we have explored the benefits of chitosan and silica by synthesizing chitosan-silica nanohybrid. In the synthesis of chitosan-silica (CS–Si) nanohybrid, chitosan is modified by thioglycolic acid and mesoporous silica MCM-41(Mobil Composition of Matter number 41) is functionalized by 3-(trimethoxysilyl)-1-propane thiol (TMSP). The modified chitosan and thiol functionalized MCM-41(inorganic network) is then linked through disulfide bond by oxidation process or oxidative coupling, resulting in the formation of inorganic-organic hybrid material. The hybrid material was characterized by FTIR, Raman, XRD, TGA, Zeta potential, EDX, Proton NMR and SEM techniques. The antibacterial results indicated that gram-negative (E. coli) bacteria exhibit better inhibition zone than gram-positive (B. subtilis) bacteria. The DPPH scavenging capability of synthesized hybrid was found to be 68%. The drug (quercetin) encapsulation efficiency of hybrid material was calculated to be 92.38% and more drug releases in acidic medium (pH 5.0) than at pH 7.4, so we can conclude that hybrid material shows pH-dependent drug releasing behavior. The results show that synthesized nano-hybrid material possess good antibacterial and antioxidant activities and is also a good nanocarrier for drug delivery application.