Granular Matrigel: restructuring a trusted extracellular matrix material for improved permeability.

Matrigel is a polymeric extracellular matrix material produced by mouse cancer cells. Over the past four decades, Matrigel has been shown to support a wide variety of two- and three-dimensional cell and tissue culture applications including organoids. Despite widespread use, transport of molecules, cells, and colloidal particles through Matrigel can be limited. These limitations restrict cell growth, viability, and function and limit Matrigel applications. A strategy to improve transport through a hydrogel without modifying the chemistry or composition of the gel is to physically restructure the material into microscopic microgels and then pack them together to form a porous material. These 'granular' hydrogels have been created using a variety of synthetic hydrogels, but granular hydrogels composed of Matrigel have not yet been reported. Here we present a drop-based microfluidics approach for structuring Matrigel into a three-dimensional, mesoporous material composed of packed Matrigel microgels, which we call granular Matrigel. We show that restructuring Matrigel in this manner enhances the transport of colloidal particles and human dendritic cells (DCs) through the gel while providing sufficient mechanical support for culture of human gastric organoids (HGOs) and co-culture of human DCs with HGOs.

Hyperspectral microscopy of subcutaneously released silver nanoparticles reveals sex differences in drug distribution.

Biomaterials have a great potential to improve human health, however in vitro and in vivo studies are necessary to provide information on their efficacy and safety. This study reports on a comprehensive evaluation of core-shell electrospun fibers loaded with silver nanoparticles (Ag NP) where the delivery rate was controlled by different sizes of Ag NP and thermoresponsive poly(n-isopropylacrylamide) (PNIPAM) hydrogel particles. Fiber meshes also contain zinc oxide nanoparticles (ZnO NP), to improve pore structure for controlled release of Ag NP. In vitro cytotoxicity studies using cultured human A549 epithelial cells demonstrated that the ZnO NP component, which is known to cause cytotoxicity, of the fiber meshes did cause measurable cell death. In vitro antibacterial efficacy of the fiber meshes was shown with rapid and efficient growth inhibition in E. coli bacterial culture. Fiber meshes were implanted subcutaneously for up to 27 days in male and female C57BL/6 mice to evaluate the in vivo drug release and biocompatibility. Hyperspectral microscopy was used as an advanced tool to determine precise location of released Ag NP into the skin compared to the conventional tissue staining methods. Results suggested that Ag NP were continuously released over 27 days of implantation in mice. Hyperspectral imaging revealed that released Ag NP dispersed in the dermis of male mice, however, Ag NP accumulated in the hair follicles of female mice (Figure). Mice implanted with fiber meshes containing ZnO NP had better hair regrowth and wound healing, which was in contrast to in vitro cytotoxicity results. These findings suggest that these newly developed fiber meshes can have unique long-term release of drugs loaded in the fiber core and appear to be biocompatible. The differences in the sex-bias outcome suggest the opportunity for development of sex-specific drug delivery systems.

Obtention of 74:26 polyester/cellulose fabric blend with super-hydrophobic and super-hydrophilic properties by air corona discharge treatment and their characterization.

A facile method was used to create both of the super-hydrophilic and super-hydrophobic properties on polyester/cellulose fabric blend. The fabric was exposed to air corona discharge treatment without any extra chemical modification. The static contact angle of 0° and 167° was indicated for super-hydrophilic and super-hydrophobic samples, respectively. The decrease of intensity of active functional groups and the increase of roughness with a nano-scale pattern presented a super-hydrophobic surface that confirmed by ATR-FTIR, AFM and FESEM analysis. This is while the increase of intensity of the active functional groups and the surface roughness with a micro-scale pattern was shown for the super-hydrophilic sample. The wettability tests show the enhancement of hydrophobic and hydrophilic properties for 300 W-10 min and 800 W-10 min corona discharge treated samples, respectively. Therefore, there is a critical point of the corona discharge process that enables it to create hydrophobic and/or hydrophilic properties on the substrates.

Thermoplastic starch/ethylene vinyl alcohol/forsterite nanocomposite as a candidate material for bone tissue engineering.

Recently, biodegradable polymers such as starch based blends have been well renowned in the biomedical field. Studies have considered them suitable for bone scaffolds, bone cements, tissue engineering scaffolds, drug delivery systems and hydrogels. The aim of this study was to synthesize nanocomposite biomaterial consisting a blend of thermoplastic starch and ethylene vinyl alcohol as the polymer matrix, and nano-structured forsterite as the ceramic reinforcing phase for bone tissue engineering applications. Furthermore, vitamin E was applied as a thermal stabilizer during melt compounding. Extrusion and injection molding were incorporated for melt blending and shaping of samples, respectively. With blending thermoplastic starch and ethylene vinyl alcohol, some properties of thermoplastic starch such as degradation rate and water absorption were modified. In addition, using nanoforsterite as the ceramic reinforcing phase resulted in the improvement of mechanical and biological traits. The addition of nanoforsterite decreased the weight loss of the thermoplastic starch and ethylene vinyl alcohol blend in simulated body fluid. Moreover, this addition modified the pH in the MTT (methyl thiazolyl tetrazolium) assay and stimulated the cell proliferation. Cell adhesion assays indicated a favorable interaction between cells and the biomaterial. The proposed nanocomposite has appropriate biocompatibility, as well as mechanical properties in order to be used in bone tissue engineering.

Temperature-Responsive Smart Nanocarriers for Delivery Of Therapeutic Agents: Applications and Recent Advances.

Smart drug delivery systems (DDSs) have attracted the attention of many scientists, as carriers that can be stimulated by changes in environmental parameters such as temperature, pH, light, electromagnetic fields, mechanical forces, etc. These smart nanocarriers can release their cargo on demand when their target is reached and the stimulus is applied. Using the techniques of nanotechnology, these nanocarriers can be tailored to be target-specific, and exhibit delayed or controlled release of drugs. Temperature-responsive nanocarriers are one of most important groups of smart nanoparticles (NPs) that have been investigated during the past decades. Temperature can either act as an external stimulus when heat is applied from the outside, or can be internal when pathological lesions have a naturally elevated termperature. A low critical solution temperature (LCST) is a special feature of some polymeric materials, and most of the temperature-responsive nanocarriers have been designed based on this feature. In this review, we attempt to summarize recent efforts to prepare innovative temperature-responsive nanocarriers and discuss their novel applications.