Microencapsulation of High-Content Actives Using Biodegradable Silk Materials.

There is a compelling need across several industries to substitute non-degradable, intentionally added microplastics with biodegradable alternatives. Nonetheless, stringent performance criteria in actives' controlled release and manufacturing at scale of emerging materials hinder the replacement of polymers used for microplastics fabrication with circular ones. Here, the authors demonstrate that active microencapsulation in a structural protein such as silk fibroin can be achieved by modulating protein protonation and chain relaxation at the point of material assembly. Silk fibroin micelles' size is tuned from several to hundreds of nanometers, enabling the manufacturing-by retrofitting spray drying and spray freeze drying techniques-of microcapsules with tunable morphology and structure, that is, hollow-spongy, hollow-smooth, hollow crumpled matrices, and hollow crumpled multi-domain. Microcapsules degradation kinetics and sustained release of soluble and insoluble payloads typically used in cosmetic and agriculture applications are controlled by modulating fibroin's beta-sheet content from 20% to near 40%. Ultraviolet-visible studies indicate that burst release of a commonly used herbicide (i.e., saflufenacil) significantly decreases from 25% to 0.8% via silk fibroin microencapsulation. As a proof-of-concept for agrochemicals applications, a 6-day greenhouse trial demonstrates that saflufenacil delivered on corn plants via silk microcapsules reduces crop injury when compared to the non-encapsulated version.

Nanoparticle-mediated gene transfer from electrophoretically coated metal surfaces.

The transfer of genetic information into living cells is a powerful tool to manipulate their protein expression by the regulation of protein synthesis. This can be used for the treatment of genetically caused diseases (gene therapy). However, the systemic application of genes is associated with a number of problems, such as a targeted gene delivery and potential side effects. Here we present a method for the spatial application of nanoparticle-based gene therapy. Titanium was electrophoretically coated with DNA-functionalized calcium phosphate nanoparticles. NIH3T3 cells and HeLa cells were transfected with pcDNA3-EGFP. We monitored the transfection in vitro by fluorescence microscopy, flow cytometry, and Western Blot analysis. By coating a transparent substrate, i.e., indium tin oxide (ITO), with nanoparticles, we followed the transfection by live cell imaging.

Biocompatibility evaluation of nano-rod hydroxyapatite/gelatin coated with nano-HAp as a novel scaffold using mesenchymal stem cells.

This study is devoted to fabricate a novel hydroxyapatite(HAp)/gelatin scaffold coated with nano-HAp in nano-rod configuration to evaluate its biocompatibility potential. The nano-HAp particles are needle and rod-like with widths ranging between 30 to 60 nm and lengths from 100 to 300 nm, respectively. Because of their higher surface area and higher reactivity, the nano-rod particles were distributed in gelatin much better than spherical and mixed shapes particles. The compressive modulus of the nano-HAp/gelatin scaffolds coated with nano-HAp was comparable with the compressive modulus of a human cancellous bone. The potential performance of the fabricated scaffolds as seeding media was assayed using mesenchymal stem cells (MSCs). MTT (3-(4,5-dimethylthiazol-2-yl)-1,5-diphenyl tetrazulium bromide) assays were performed on days 4 and 7 and the number of the cells per scaffold was determined. On the basis of this assay, all the studied scaffolds exhibited an appropriate environment in which the loaded cells appeared to be proliferated during the cultivation periods. In all fabricated composite scaffolds, marrow-derived MSCs appeared to occupy the scaffolds internal spaces and attach on their surfaces. According to the cell culture experiments, the incorporation of rod-like nano-HAp and coating of scaffolds with nano-HAp particles enabled the prepared scaffolds to possess desirable biocompatibility, high bioactivity, and sufficient mechanical strength in comparison with noncoated HAp samples. This research suggests that the newly developed scaffold has a potential as a suitable scaffold for bone tissue engineering.