Functionalized mesoporous silica for drug delivery of poorly soluble polyphenols: Synthesis, characterization, and antimicrobial action

Abstract

The synthesis of mesoporous silica nanoparticles (MSN) and their functionalization have gained significant attention in various biomedical fields. MSNs are nanoscale particles composed of silica with ordered pore structures and high surface areas, which make them excellent candidates for a wide range of applications, including drug delivery, imaging, biosensing, and tissue engineering. The focus of the present study is to explore the role of 12-tungstophosphoric acid (TPA) functionalized nMCM-48 for drug delivery of two weakly soluble polyphenols; curcumin, and quercetin, for effective antimicrobial action. Quercetin (Q) and curcumin (C) are simultaneously encapsulated in TPA-functionalized nMCM-48 to achieve C-TPA/nMCM-48 and Q-TPA/nMCM-48, nanocomposites respectively. The TPA functionalized nMCM-48 exhibited high pore volume, pore diameter and high surface area, the primary requirements for effective drug loading and release. The nanocomposite were characterized using several analytical methods, including FESEM, EDX, BET, XRD and FTIR. The FESEM analysis, demonstrating retainment of uniform spherical shape of the particles and homogeneous dispersion of drugs C or Q, in Q-TPA/nMCM-48 and C-TPA/nMCM-48. The EDX gives the confirmation of drug-loaded carriers, C-TPA/nMCM-48 and Q-TPA/nMCM-48 validates the presence of all elements indicating the successful loading of both C and Q. The high drug loading content 84% and 86% in the case of C and Q over C-TPA/nMCM-48 and Q-TPA/nMCM-48, respectively, was observed due to the high porosity of the material. In-vitro drug release studies for C-TPA/nMCM-48 and Q-TPA/nMCM-48 were carried out at physiological temperatures and different pH conditions. The percentage of drug release observed in case of C-TPA/nMCM-48 was 69% and for Q-TPA/nMCM-48 was 67%. The antimicrobial efficacy of nano systems was studied by bacterial growth curve analysis, zone of inhibition, MIC studies, and morphological analysis of cells. The nanocomposites exhibited enhanced antimicrobial efficiency due to the synergistic effect of a polyphenol drug molecule (C or Q) and TPA in nMCM-48 matrices. The bacterial growth curve was significantly affected and a prominent growth inhibition of microbes was observed in the presence of drug loaded samples C-TPA/nMCM-48, Q-TPA/nMCM-48. The antimicrobial efficiency of C-TPA/nMCM-48, Q-TPA/nMCM-48 was carried out against E.coli and the minimum inhibition concentration values were 25 μg/mL and 25 μg/mL, respectively. The zone of inhibition for C-TPA/nMCM-48 was detected as 1.5 ± 0.2 mm and for Q-TPA/nMCM-48 as 1.3 ± 0.3 mm against E.coli. The intricate interactions between drugs and TPA within nMCM-48 is a key facet that controls the properties of nanocomposite as a drug delivery system.