Preparation and characterization of biosilicate composites for drug delivery applications

Abstract

Ordered MSNs materials have a lot of advantages to be used as multifunctional nanostructured drug delivery systems attributed to their biocompatibility, bioavailability, textural and structural properties. The drug formulation in Nano carrier systems would improve the therapeutic efficacy, the local concentration was increased with simultaneously systemic concentration decreased with fewer side effects. In the present study, we loaded Ceftriaxone on bare mesoporous silica nanoparticles at 10 mg/ml (CFX: MSNs, 1:1) to achieve the local delivery of CFX antibiotic against gram positive and gram negative bacteria. The size, charge, crystallinity, morphology, stability and composition were studied by using DLS, ζ-potential measurements, HR-TEM, SXRD, FT-IR and TGA. The mesostructured properties included surface area, and pore size and pore volume were studied by using N2 Adsorption-Desorption Isotherm. The total antibiotic loading was 195 µg per mg MSNs, the loading and Encapsulation efficiency were 19.59 %. Minimum inhibitory concentration (MIC) of CFX and Cu2+ ions were calculated by using Two-fold micro-dilution method. MIC of CFX were higher than 128 µg/ml and 256 µg/ml of E. coli and S. aureus, respectively. While, MIC of Cu2+ ions were 852 µg/ml and 1704 µg/ml of E. coli and S. aureus, respectively. MSNs-CFX and MSNs based Ca and Cu alginate hydrogel nanocomposites loaded with CFX were formulated and tested for antibacterial activity against 105 CFU/ml by using CLSM imaging and CFU counting test against 104 CFU/ml of both gram negative E. coli and gram positive S. aureus bacteria. The antibacterial efficacy was higher for CFX loaded MSNs (CFX, 390 µg/ml) compared to free CFX antibiotic (2 mg/ml) even though the cytotoxicity was lower. Both MSNs and CFX loaded MSNs were effective against Gram-negative and Gram-positive bacteria. Cu-alginate and Ca-alginate hydrogels with higher percentage of 10% MSNs-CFX showed the better storage ability for CFX drug that can be successfully used as good drug carrier for biomedical applications. In addition, bacterial reduction and viability % results revealed that, the highest bactericidal effect after 24h of Cu-alginate based 10% and 5% MSNs-CFX followed by Ca-alginate based 10% MSNs-CFX.