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

Development of dissolvable microneedle patches by CNC machining and micromolding for drug delivery

This study reports the fabrication of microneedles using computer numerical control (CNC) machining and micromolding for replicating dissolvable microneedles (DMNs) for drug delivery. Despite the ease of use and simple manufacturing by CNC, this method has not been extensively studied for the fabrication of microneedles. The master molds were fabricated using CNC machining; subsequently, DMNs embedded with fluorescent dye as a drug model were prepared using a hyaluronic acid (HA) and polyvinylpyrrolidone (PVP) solution in a rapid and comparatively simple micromolding process. The microneedles were evaluated for mechanical strength and penetration efficiency. The drug diffusion from DMNs was elucidated through confocal laser scanning microscopy (CLSM) imaging. The results show that fabricated DMNs are mechanically strong enough to penetrate the skin dermis layer and deliver their therapeutic cargo. In conclusion, CNC machining can provide rapid and low-cost fabrication of master molds, facilitating DMNs production for transdermal drug delivery