Zhi-Cheng Yao has completed his Bachelor’s degree from Zhejiang University, College of Biomedical Engineering & Instrument Science, in 2015, and is now proceeding for a Master’s degree. He has been focusing on preparing composite materials by encapsulating naturally bioactive components into biocompatible polymers via electrospinning/electrospraying technique, and evaluating the physicochemical and biological properties of the fabricated materials. He has published 2 journal articles and applied for a patent about modulating the characteristics of the electrospun fibers and preparing composite fibrous membranes for food preservation.
Micro-fibers (MFs) and micro-particles (MPs) with desirable porous structures are critical in drug delivery. In this study, surface morphologies of MFs and MPs were varied via non-solvent-based during electrohydrodynamic process. One-step control of fiber diameter and morphology is demonstrated using three liquids (ethanol, dimethyl silicone oil and mineral oil) serving as the non-solvent outer-flowing medium during the coaxial process. Poly-caprolactone (PCL) fibers with various surface morphologies (porous, rough and smooth) were prepared. The results clearly show the modified enveloping liquid coaxial electrospinning (ES) approach permits fiber size regulation, hydrophobic enhancement and surface topography (See Figure 1). Furthermore, non-solvent collection medium were used to generate porous particles hosting drug (indomethacin) and magnetic Fe3O4 nanoparticles (NPs) in single-step electrospraying technique (See Figure 2). In vitro drug release analysis for both porous and solid (non-porous) particle systems demonstrated a short drug burst period followed by a prolonged phase of dissolutive drug release, which is based on Fickian diffusion. Subsequently, with external alternating magnetic fields (AMF, 40 kHz), the release rate of drug from drug-magnetic porous microspheres was characterized, facilitating drug release over the established Fickian process. This work indicates a versatile and efficient method for preparing porous materials via non-solvent-based approach, which further enables controlled surface hydrophobic property and drug release kinetics of the fabricated drug carriers.
Shota Sasaki is in science and technology doctoral course in Gunma University. He has specialized in molecular biology of metabolism of hepatocyte. He had contributed to publish 2 papers in reputed journals.
Hepatocytes play a central role in drug metabolism in liver. In pharmacokinetics tests of new drugs, normal human hepatocytes have been used for evaluation of the drugs. However, supply of the hepatocytes is unstable and it costs expensive. Thus, development of efficient hepatocyte differentiation system using ES and iPS cells has been desired for a long time. Previous studies showed that hepatocyte nuclear factor 4 (HNF4), an orphan member of the nuclear receptor superfamily and a master regulator in liver homeostasis, is an essential factor for differentiation of hepatocytes from hepatoblasts and iPS cells. In addition to HNF4, HNF4 family contains other isoform, HNF4 in mammals. Because hepatic HNF4 is hardly detected in normal liver, function of HNF4 remain to be clarified. We found that hepatic expression of HNF4 is markedly up-regulated in liver-specific Hnf4a-null mice. Furthermore, two HNF4 variants that have different N-terminal exon, known HNF41 and novel HNF42, are also up-regulated in the Hnf4a-null mice. Therefore, we investigated whether the HNF4 variants induce transcriptional activity and mRNA expression of the HNF4 target genes. As a result, HNF42, but not HNF41 was found to have strong transcriptional activity and induce expression of many liver-enriched genes in HCC-derived HepG2 cells when compared to HNF4, suggesting that HNF42 could be a new hepatocyte redifferentiation factor. These findings may contribute to establishment of differentiated hepatocytes using ES and iPS cells and development of HCC therapy by introducing HNF42.