Porphyrin-based honeycomb films and their antibacterial activity.

Micrometer-sized porous honeycomb-patterned thin films based on hybrid complexes formed via electrostatic interaction between Mn(III) meso-tetra(4-sulfonatophenyl) porphine chloride (an acid form, {MnTPPS}) and dimethyldioctadecylammonium bromide (DODMABr). The morphology of the microporous thin films can be well regulated by controlling the concentration of MnTPPS-DODMA complexes, DODMABr, and polystyrene (PS), respectively. The formation of the microporous thin films was largely influenced by different solvents. The well-ordered microporous films of MnTPPS-DODMA complexes exhibit a more efficient antibacterial activity under visible light than those of hybrid complexes of nanoparticles modified with DODMABr, implying that well-ordered microporous films containing porphyrin composition can improve photochemical activity and more dominance in applications in biological medicine fields.

Electrospun Polyurethane-Gelatin Composite: A New Tissue-Engineered Scaffold for Application in Skin Regeneration and Repair of Complex Wounds.

Wound healing is vital for patients with complex wounds including burns. While the gold standard of skin transplantation ensures a surgical treatment to heal wounds, it has its limitations, for example, insufficient donor sites for patients with large burn wounds and creation of wounds and pain when harvesting the donor skin. Therefore, tissue-engineered skin is of paramount importance. The aim of this study is to investigate and characterize an elastomeric acellular scaffold that would demonstrate the ability to promote skin regeneration. A hybrid gelatin-based electrospun scaffold is fabricated via the use of biodegradable polycarbonate polyurethane (PU). It is hypothesized that the addition of PU would enable a tailored degradation rate and an enhanced mechanical strength of electrospun gelatin. Introducing 20% PU to gelatin scaffolds (Gel80-PU20) results in a significant increase in the degradation resistance, yield strength, and elongation of these scaffolds without altering the cell viability. In vivo studies using a mouse excisional wound biopsy grafted with the scaffolds reveals that the Gel80-PU20 scaffold enables greater cell infiltration than clinically established matrices, for example, Integra (dermal regeneration matrix, DRM), a benchmark scaffold. Immunostaining shows fewer macrophages and myofibroblastic cells on the Gel80-PU20 scaffold when compared with the DRM. The findings show that electrospun Gel80-PU20 scaffolds hold potential for generating tissue substitutes and overcoming some limitations of conventional wound care matrices.

A core-shell albumin copolymer nanotransporter for high capacity loading and two-step release of doxorubicin with enhanced anti-leukemia activity.

The native transportation protein serum albumin represents an attractive nano-sized transporter for drug delivery applications due to its beneficial safety profile. Existing albumin-based drug delivery systems are often limited by their low drug loading capacity as well as noticeable drug leakage into the blood circulation. Therefore, a unique albumin-derived core-shell doxorubicin (DOX) delivery system based on the protein denaturing-backfolding strategy was developed. 28 DOX molecules were covalently conjugated to the albumin polypeptide backbone via an acid sensitive hydrazone linker. Polycationic and pegylated human serum albumin formed two non-toxic and enzymatically degradable protection shells around the encapsulated DOX molecules. This core-shell delivery system possesses notable advantages, including a high drug loading capacity critical for low administration doses, a two-step drug release mechanism based on pH and the presence of proteases, an attractive biocompatibility and narrow size distribution inherited from the albumin backbone, as well as fast cellular uptake and masking of epitopes due to a high degree of pegylation. The IC50 of these nanoscopic onion-type micelles was found in the low nanomolar range for Hela cells as well as leukemia cell lines. In vivo data indicate its attractive potential as anti-leukemia treatment suggesting its promising profile as nanomedicine drug delivery system.