Development of functionalized chitosan-coated carboxylated mesoporous silica: a dual drug carrier

Mesoporous Silica-Based Materials with Bactericidal Properties

Bacterial infections are the main cause of chronic infections and even mortality. In fact, due to extensive use of antibiotics and, then, emergence of antibiotic resistance, treatment of such infections by conventional antibiotics has become a major concern worldwide. One of the promising strategies to treat infection diseases is the use of nanomaterials. Among them, mesoporous silica materials (MSMs) have attracted burgeoning attention due to high surface area, tunable pore/particle size, and easy surface functionalization. This review discusses how one can exploit capacities of MSMs to design and fabricate multifunctional/controllable drug delivery systems (DDSs) to combat bacterial infections. At first, the emergency of bacterial and biofilm resistance toward conventional antimicrobials is described and then how nanoparticles exert their toxic effects upon pathogenic cells is discussed. Next, the main aspects of MSMs (e.g., physicochemical properties, multifunctionality, and biosafety) which one should consider in the design of MSM-based DDSs against bacterial infections are introduced. Finally, a comprehensive analysis of all the papers published dealing with the use of MSMs for delivery of antibacterial chemicals (antimicrobial agents functionalized/adsorbed on mesoporous silica (MS), MS-loaded with antimicrobial agents, gated MS-loaded with antimicrobial agents, MS with metal-based nanoparticles, and MS-loaded with metal ions) is provided.

Applications of mesoporous silica in biosensing and controlled release of insulin

The development of new oral insulin delivery systems could bring significant benefits to insulin-dependent patients due to the simplicity of the method, avoidance of pain caused by parenteral administration and maintenance of optimal therapeutic levels for a longer period. However, administration of such therapeutic proteins orally remains a challenge because insulin (Ins) is a very sensitive molecule and can be easily degraded under the existing pH conditions in the stomach and intestines. Moreover, due to the large size of insulin, intestinal epithelium permeability is very low. This could be improved by immobilizing insulin in the mesoporous silica pores (MSN), acting as a shield to protect the molecule integrity from the proteolytic degradation existing in the stomach and upper part of the small intestine. Due to the high adsorption capacity of insulin, biocompatibility, ease of functionalization with various organic and/or inorganic groups, high mechanical and chemical resistance, adjustable pore size and volume, MSN is considered an ideal candidate for the development of controlled release systems that are sensitive to various stimuli (pH, temperature) as well as to glucose. Modifying MSN surfaces by coating with various mucoadhesive polymers (chitosan, alginate, etc.) will also facilitate interaction with the intestinal mucus and improve intestinal retention time. Moreover, the development of glucose-responsive systems for achieving MSN-based self-regulated insulin delivery, decorated with various components serving as sensors - glucose oxidase (GOD_x) and phenylboronic acid (PBA) that can control the insulin dosage, avoiding overdose leading to serious hypoglycemia. MSN have also been tested for application as biosensors for glucose monitoring.

Facile Synthesis of Chitosan Capped Mesoporous Silica Nanoparticles: A pH Responsive Smart Delivery Platform for Raloxifene Hydrochloride

An encapsulation of model drug raloxifene hydrochloride (RAL) inside the chitosan decorated pH responsive mesoporous system has a greater potential for accumulating in the tumor cells. The present study involves synthesis of surface modified mesoporous silica nanoparticles (MSN) with the aim of achieving pH sensitive drug delivery system. A silanol skeleton of MSN has been productively modified to amine intermediate which served as a firm platform to adapt chitosan grafted assembly and systematically evaluated. RAL incorporation inside the featured mesopores was performed employing novel immersion solvent evaporation methodology and evaluated further. The pH responsive behavior of formulated nano framework was studied at three different pH of a phosphate buffer saline individually. The in vitro cell viability assay on MCF-7 breast carcinoma cells was performed in time and concentration dependent manner. Finally, the hemolysis assay of designed nanoparticle was accomplished to envisage the hemocompatibility. The outcome of characterization details unveiled a perfect 2D hexagonal spherical structure gifted with higher surface area and optimum pore size for designed nanoparticles. The higher percentage grafting of amine and chitosan residue, i.e., 4.01 and 28.51% respectively along with 31.89 and 33.57% RAL loading efficiency made MSNs more attractive and applicable. Eventually, in vitro release study exhibited higher RAL release in acidic media for extended time periods confirming successful formation of pH responsive nanoparticle having controlled release property. Conclusively potential of designed nanosystem to serve efficient anti-cancer remedy was confirmed by superior behaviour of chitosan grafted MSN towards MCF-7 cells with supreme hemocompatibility.

Temperature and ultrasound sensitive gatekeepers for the controlled release of chemotherapeutic drugs from mesoporous silica nanoparticles

The copolymer chains were grafted onto the mesopores of silica nanoparticles and could act as stimuli responsive ‘smart’ gatekeepers. With the aid of a transdermal delivery route and ultrasound penetration, even malignant sites of internal organs can be set as targets.

Multi-polysaccharide based stimuli responsive polymeric network for the in vitro release of 5-fluorouracil and levamisole hydrochloride

A three-polysaccharide-based core shell system is reported for the first time for the delivery of dual drugs.