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.

Engineering and Development of a Tissue Model for the Evaluation of Microneedle Penetration Ability, Drug Diffusion, Photothermal Activity, and Ultrasound Imaging: A Promising Surrogate to Ex Vivo and In Vivo Tissues.

Driven by regulatory authorities and the ever-growing demands from industry, various artificial tissue models have been developed. Nevertheless, there is no model to date that is capable of mimicking the biomechanical properties of the skin whilst exhibiting the hydrophilicity/hydrophobicity properties of the skin layers. As a proof-of-concept study, tissue surrogates based on gel and silicone are fabricated for the evaluation of microneedle penetration, drug diffusion, photothermal activity, and ultrasound bioimaging. The silicone layer aims to imitate the stratum corneum while the gel layer aims to mimic the water-rich viable epidermis and dermis present in in vivo tissues. The diffusion of drugs across the tissue model is assessed, and the results reveal that the proposed tissue model shows similar behavior to a cancerous kidney. In place of typical in vitro aqueous solutions, this model can also be employed for evaluating the photoactivity of photothermal agents since the tissue model shows a similar heating profile to skin of mice when irradiated with near-infrared laser. In addition, the designed tissue model exhibits promising results for biomedical applications in optical coherence tomography and ultrasound imaging. Such a tissue model paves the way to reduce the use of animals testing in research whilst obviating ethical concerns.

Polysorbate-coated mesoporous silica nanoparticles as an efficient carrier for improved rivastigmine brain delivery.

Targeted delivery of neurological therapeutic to the brain has been attracting more and more attention to the treatment of central nervous system (CNS) diseases. Nonetheless, the main obstacle in this road map is the existence of a blood-brain barrier (BBB) which limits the penetration efficiency of most CNS drugs into the brain parenchyma. This present investigation describes a facile synthetic strategy to prepare a highly biocompatible calcium-doped mesoporous silica nanoparticles (MSNs) functionalized by polysorbate-80 (PS) as targeting ligand to deliver rivastigmine (RV) into the brain via crossing the BBB. The developed nanosystem was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), Zeta potential, and N2-adsorption-desorption analysis. In vitro hemolysis studies were carried out to confirm the biocompatibility of the nanocarriers. Our in vivo studies in an animal model of rats showed that the RV-loaded nanosystem was able to enhance the brain-to-plasma concentration ratio, brain uptake clearance, and plasma elimination half-life of the drug compared to the free one drug following intravenous (IV) administration. The results revealed that functionalization of MSNs by PS is crucial to deliver RV into the brain, suggesting PS-functionalized MSNs could be an effective carrier to deliver RV to the brain while overcoming BBB.

Preparation and in vitro/pharmacokinetic/pharmacodynamic evaluation of a slow-release nano-liposomal form of prednisolone.

A nano-liposomal carrier was prepared for the anti-inflammatory drug prednisolone acetate (PA). The drug showed remarkable loading in the nano-carriers. The drug-loaded nano-liposmes with average sizes of about 186 nm and zeta potentials of -20 mV were obtained. Our drug release studies showed an apparently zero-order trend with only 18% of the drug released in the first 120 h. Fourier transform infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC) analyses showed no chemical interaction between the drug and carrier. Transmission electron microscopy (TEM) imaging showed near-spherical drug-containing nano-carriers. The intramuscular (IM) trial of the nanoformulation compared with the free drug showed both pharmacokinetic (lower Cmax, higher area under the curve (AUC)) and pharmacodynamic (higher and longer lasting anti-inflammatory effect, both macroscopically and biochemically) superiority for the nano-liposomal drug above the free prednisolone in rats.