Bioinspired nanovalves with selective permeability and pH sensitivity.

Biological systems with controlled permeability and release functionality, which are among the successful examples of living beings to survive in evolution, have attracted intensive investigation and have been mimicked due to their broad spectrum of applications. We present in this work, for the first time, an example of nuclear pore complexes (NPCs)-inspired controlled release system that exhibits on-demand release of angstrom-sized molecules. We do so in a cost-effective way by stabilizing porous cobalt basic carbonates as nanovalves and realizing pH-sensitive release of entrapped subnano cargo. The proof-of-concept work also consists of the establishment of two mathematical models to explain the selective permeability of the nanovalves. Finally, gram-sized (or larger) quantities of the bio-inspired controlled release system can be synthesized through a scaling-up strategy, which opens up opportunities for controlled release of functional molecules in wider practical applications.

Potential of alginate fibers incorporated with drug-loaded nanocapsules as drug delivery systems.

A major problem related to the fabrication of drug-loaded fibers by wet spinning is the significant loss of load when the drugs and spinning dopes are directly mixed together. We report a novel method to fabricate drug-loaded alginate fibers by spinning an aqueous mixture containing alginate and alginate nanocapsules incorporated with drugs. The alginate fibers exhibit spotty features of nanocapsules located close to the surface of the fibers. Adsorption experiments demonstrate the superabsorbent properties of the fibers, as well as the dependence of adsorption profiles on salt ionic strength. The adsorption processes of all the fibers are well-described by the pseudo-second-order kinetics model. Drug release tests show that the cumulative release amount increased with an increase in the proportion of nanocapsules present in the fiber. In addition, the burst release behaviors of the fibers incorporated with the nanocapsules were also diminished dramatically. This work suggests that adding nanocapsules containing drugs into the spinning dopes is a promising strategy to fabricate novel drug-loaded fibers for immediate drug delivery for wound dressing.