Microencapsulation-protectedl-ascorbic acid for the application of human epithelial HaCaT cell proliferation

Can l-ascorbic acid and trans-resveratrol protect HaCaT cells from fine particulate matter toxicity?

Continuous exposure of human skin to air pollution can result in a range of undesirable skin conditions. In our recent study, UV and visible light were found to increase cytotoxicity of fine particulate matter (PM2.5 ) against human keratinocytes. Since it is impossible to avoid exposure of human skin to PM2.5 , effective strategies are needed to reduce their damaging effects. l-ascorbic acid and resveratrol were tested as potential topical agents against pollution-related skin impairment. Although these agents were previously found to ameliorate PM-dependent damage, the effect of light and seasonal variation of particles were not previously studied. EPR spin-trapping, DPPH assay, and singlet oxygen phosphorescence were used to determine the scavenging activities of the antioxidants. MTT, JC-10 and iodometric assays were used to analyze the effect on PM2.5 -induced cytotoxicity, mitochondrial damage and oxidation of lipids. Live-cell imaging was employed to examine wound-healing properties of cells. Light-induced, PM2.5 -mediated oxidative damage was examined by immunofluorescent staining. Both antioxidants effectively scavenged free radicals and singlet oxygen produced by PM2.5 , reduced cell death and prevented oxidative damage to HaCaT cells. l-ascorbic acid and resveratrol, especially when applied in combination, can protect HaCaT cells against the dark and light induced toxicity of PM2.5 .

Surface-Eroding Poly(ortho ester amides) for Highly Efficient Oral Chemotherapy

Two new poly(ortho ester amide) copolymers (POEA-4 and POEA-5) were synthesized via polycondensation of a new ortho ester diamine monomer with active esters of different aliphatic diacids. The kinetics of POEA mass loss and release of 5-FU were both nearly zero-order, suggesting predominantly surface-restricted polymer erosion and drug release. In vitro cytotoxicity tests demonstrated that both copolymers have excellent biocompatibility. In vivo acute toxicity tests suggested that oral administration of POEA-4 and POEA-5 did not cause any adverse effects on mice even at a very high dose (2000 mg/kg). In vivo antitumor efficacy against H22 transplanted tumors of 5-FU-loaded POEA tablets were fully examined. We envision that, with further optimization, POEA-based materials could have great potential as drug carriers for oral chemotherapy.

Sustained Release of Hydrophilic l-ascorbic acid 2-phosphate Magnesium from Electrospun Polycaprolactone Scaffold-A Study across Blend, Coaxial, and Emulsion Electrospinning Techniques

The purpose of this study was to achieve a sustained release of hydrophilic l-ascorbic acid 2-phosphate magnesium (ASP) from electrospun polycaprolactone (PCL) scaffolds, so as to promote the osteogenic differentiation of stem cells for bone tissue engineering (TE). ASP was loaded and electrospun together with PCL via three electrospinning techniques, i.e., coaxial, emulsion, and blend electrospinning. For blend electrospinning, binary solvent systems of dichloromethane–methanol (DCM–MeOH) and dichloromethane–dimethylformamide (DCM–DMF) were used to achieve the desired ASP release through the effect of solvent polarity and volatility. The scaffold prepared via a blend electrospinning technique with a binary solvent system of DCM–MeOH at a 7:3 ratio demonstrated a desirable, sustained ASP release profile for as long as two weeks, with minimal burst release. However, an undesirable burst release (~100%) was observed within the first 24 h for scaffolds prepared by coaxial electrospinning. Scaffolds prepared by emulsion electrospinning displayed poorer mechanical properties. Sustained releasing blend electrospun scaffold could be a good potential candidate as an ASP-eluting scaffold for bone tissue engineering.