Poly-l-lactic acid scaffold incorporated chitosan-coated mesoporous silica nanoparticles as pH-sensitive composite for enhanced osteogenic differentiation of human adipose tissue stem cells by dexamethasone delivery

Nowadays, the development of drug-loaded electrospun organic-inorganic composite scaffolds for tissue engineering application is an attractive approach. In this study, a composite scaffold of Poly-l-lactic acid (PLLA) incorporated dexamethasone (Dexa) loaded Mesoporous Silica Nanoparticles (MSN) coated with Chitosan (CS) were fabricated by electrospinning for bone tissue engineering application. The MSN was prepared by precipitation method. After that, Dexamethasone (Dexa) was loaded into MSNs (MSN-Dexa). In the following, CS was coated over the prepared nanoparticles to form MSN-Dexa@CS and then, were mixed to PLLA solution to form MSN-Dexa@CS/PLLA composite for electrospinning. The surface morphology, hydrophilicity, tensile strength and the bioactivity of the scaffolds were characterized. The osteogenic proliferation and differentiation potential were evaluated by MTT assay and by measuring the basic osteogenic markers: the activity of the enzyme alkaline phosphatase and the level of calcium deposition. The composite scaffolds prepared here have conductive surface property and have a better osteogenic potential than pure PLLA scaffolds. Hence, the controlled release of nanoparticle containing Dexa from composite scaffold supported the osteogenesis and made the composite scaffolds ideal candidates for bone tissue engineering application and pH-sensitive delivery of drugs at the site of implantation in tissue regeneration. Keywords Author Keywords:Mesoporous silica nanoparticles; electrospinning; Poly-l-lactic acid; chitosan; dexamethasone; composite scaffold; bone tissue engineering KeyWords Plus:DRUG-DELIVERY; BONE; SYSTEM; NANOFIBERS; SURFACE; POLY(L-LACTIDE); PROLIFERATION; CARTILAGE; RELEASE; PEPTID

Antimicrobial action of mesoporous silica nanoparticles loaded with cefepime and meropenem separately against multidrug-resistant (MDR) Acinetobacter baumannii

The extensive use of antibiotics drives the evolution of drug resistance in pathogenic bacteria clearly. Multidrug-resistance (MDR) is being a major challenge in world public health and A. baumannii is becoming an increasingly important human pathogen due to the emergence of MDR strains. In this study, amine-functionalized mesoporous silica nanoparticles (MSN-NH2) was synthesized and loaded by cefepime (CEF) and meropenem (MEP) as antibiotic drugs. The results showed a high loading efficiency of the CEF and MEP into MSN-NH2 (MSN�NH2�CEF and MSN�NH2�MEP). The prepared nanoparticles were fully characterized by Scanning Electron Microscopy (SEM), nitrogen adsorption/desorption isotherms, Fourier Transform Infrared (FT-IR) spectroscopy, and X-ray Diffraction (XRD) spectroscopy. In order to determine the antibacterial action of MSN�NH2�CEF and MSN�NH2�MEP against MDR A. baumannii, the broth microdilution and well diffusion method were used. The antimicrobial test results against MDR A. baumannii isolate were showed that drug-loaded MSN-NH2 more effective than the free drug. The results of the present study demonstrated that MSN�NH2�CEF and MSN�NH2�MEP potentiate antimicrobial activity than free drugs and enhanced the possibility of combat against A. baumannii isolate

Enhancement Antimicrobial Activity of Clarithromycin by Amine Functionalized Mesoporous Silica Nanoparticles as Drug Delivery System

Methods: A large pore amine functionalized MSN (MSNs-NH2) is described here to facilitate delivery of clarithromycin (CLM) as an antibacterial drug and enhance the efficacy against Gram positive and Gram negative bacterial samples. Prepared particles were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), nitrogen adsorption/desorption isotherms, Fourier Transform Infrared (FT-IR) spectroscopy and X-ray Diffraction (XRD) spectroscopy. The antimicrobial activity was evaluated by agar well diffusion and broth dilution methods. Therefore, the biodistribution of FITC-MSNs was investigated by measure the NIR intensity fluorescent of fluorescent images from whole animal and dissected organs of NMRI mice. Results: The results showed that the CLM loaded MSNs-NH2 (CLM/MSNs-NH2) were successfully prepared having good payload and pH-sensitive drug release kinetics. The antimicrobial investigation against Staphylococcus aureus and Escherichia coli was showed better performance of antimicrobial activity of these nanoparticles. In vivo and ex vivo fluorescent imaging investigation on NMRI mice were shown that FITC-MSNs-NH2 accumulated in the liver and kidney and notably in lung tissue. Conclusion: The CLM/MSNs-NH2 exhibited higher antimicrobial activity and enhanced the possibility of microbial infection therapy especially at respiratory infection