Sericin Ameliorates the Properties of Poly(Vinyl Alcohol) Hydrogel Prepared by Simple Repeated Freeze-Thaw Process without the Use of Chemical Crosslinking

Hydrogel of polyvinyl alcohol (PVA) and sericin can be easily produced using a repeated freeze-thaw process. The effects of polymer concentration (4-8 %wt), blending ratio of PVA/sericin (100/0-50/50), and the number of freeze-thawing cycle (4, 8, and 12 cycles) on chemical and physical properties of the hydrogels obtained were studied. We here showed that higher polymer concentration, higher PVA ratio, and more cycles of freeze-thawing produced the hydrogels with high gel (crosslinked) fraction (>90), wall-like structure, and high compressive modulus (100-170 kPa). When the sericin ratio was increased, the hydrogels showed less gel fraction (60-80), more porous structure with highly interconnected pores, and better swelling ability (up to 8-9 times of its original state). The formation of the PVA/sericin hydrogels was occurred by the conformational changes of both PVA and sericin. The secondary structures of PVA and sericin turned to more stable crystalline conformation during the freeze-thawing process, as confirmed by fourier transform infrared (FTIR) spectroscopic results. Furthermore, all hydrogels were not toxic to human skin keratinocytes (HaCaT) cells while the anti-oxidant activity of sericin component in hydrogels was confirmed. We concluded that the freeze-thawing process was a simple and effective technique for fabrication of PVA and sericin, which both are water-soluble, into the stable hydrogels without the use of any chemical solvents or further crosslinking. More importantly, sericin enhances the biological activities of the hydrogels, allowing the use of this hydrogel in various medical applications such as wound dressing

Microfluidic analysis techniques for safety assessment of pharmaceutical nano- and microsystems

This chapter reviews the evolution of microfabrication methods and materials, applicable to manufacturing of micro total analysis systems (or lab‐on‐a‐chip), from a general perspective. It discusses the possibilities and limitations associated with microfluidic cell culturing, or so called organ‐on‐a‐chip technology, together with selected examples of their exploitation to characterization of pharmaceutical nano‐ and microsystems. Materials selection plays a pivotal role in terms of ensuring the cell adhesion and viability as well as defining the prevailing culture conditions inside the microfluidic channels. The chapter focuses on the hepatic safety assessment of nanoparticles and gives an overview of the development of microfluidic immobilized enzyme reactors that could facilitate examination of the hepatic effects of nanomedicines under physiologically relevant conditions. It also provides an overview of the future prospects regarding system‐level integration possibilities facilitated by microfabrication of miniaturized separation and sample preparation systems as integral parts of microfluidic in vitro models.Non peer reviewe

Copper Oxide Nanoparticles Cause a Dose-Dependent Toxicity via Inducing Reactive Oxygen Species in Drosophila

Copper oxide nanoparticles (CuONPs) have attracted considerable attention, because of their biocide potential and capability for optical imaging, however CuONPs were shown to be highly toxic in various experimental model systems. In this study, mechanism underlying CuONP-induced toxicity was investigated using Drosophila as an in vivo model. Upon oral route of administration, CuONPs accumulated in the body, and caused a dose-dependent decrease in egg-to-adult survivorship and a delay in development. In particular, transmission electron microscopy analysis revealed CuONPs were detected inside the intestinal epithelial cells and lumen. A drastic increase in apoptosis and reactive oxygen species was also observed in the gut exposed to CuONPs. Importantly, we found that inhibition of the transcription factor Nrf2 further enhances the toxicity caused by CuONPs. These observations suggest that CuONPs disrupt the gut homeostasis and that oxidative stress serves as one of the primary causes of CuONP-induced toxicity in Drosophila

Poster Session Abstracts

Nanoinformatics 2010 held a poster session on November 3, 2010 as part of the overall workshop program. 17 posters were accepted for exhibition

Beneficial Effects of Young Coconut Juice on Increasing Skin Thickness, Enhancing Skin Whitening, and Reducing Skin Wrinkles in Ovariectomized Rats

It has been previously demonstrated in light microscopic and immunohistochemical studies that ovariectomized rats receiving young coconut juice at 100 mL/kg BW showed much better wound healing and improved skin complexion. Nevertheless, it was found that young coconut juice at 100 mL/kg BW/day caused unfavorable side effects, such as glycogen deposition in the liver. Therefore, in the current study, 3 lower doses (10, 20, and 40 mL/kg BW/day) were optimized, and the ultrastructure was further investigated. Compared to normal rats, all the parameters regarding skin changes, including epidermal and dermal thickness, the number of hair follicles, the diameters of collagen fibrils, perimeters, and nuclei of fibroblast and keratinocyte cells, and ultrastructural changes in keratinocyte and fibroblast cells were significantly reduced in ovariectomized rats. Those parameters in the ovariectomized rats were restored to normal by injecting estradiol benzoate or by feeding young coconut juice to the rats, where the effect was found to be dose-related but not in the case of all the parameters. In most cases, a dose of young coconut juiceof 40 mL/kg BW/day was the optimal dose. The results suggest that young coconut juice may be as effective as estradiol benzoate in reducing skin atrophy/aging, probably as a selective estrogen receptor moderator

Discovery of Carcinogenic Liver Fluke Metacercariae in Second Intermediate Hosts and Surveillance on Fish-Borne Trematode Metacercariae Infections in Mekong Region of Myanmar

Countries of lower Mekong regions are highly alarmed by the spread of fish-borne trematode infections, i.e., small liver flukes and minute intestinal flukes especially in Thailand, Lao People’s Democratic Republic (Lao PDR), Vietnam, Cambodia and Myanmar. Moreover; the incidence of cholangiocarcinoma has also been increasing in the endemic area of liver fluke infections. Only a few reports have been published concerning the fish-borne trematodes infections in the central region of Myanmar. However; there is still a lack of information regarding the status of trematodes infections in second intermediate hosts in the Mekong region of Myanmar. Therefore, we conducted surveillance on the distribution of trematode metacercariae in small cyprinoid fishes collected from the Mekong region of Myanmar. A total of 689 fishes (12 different species of cyprinoid fishes) have been collected and examined by pepsin digestion methods. We discovered four species of fish-borne trematode metacercariae infections, i.e., carcinogenic liver fluke, Opisthorchis viverrini; minute intestinal flukes, Haplorchis taichui; Haplorchis pumilio and Haplorchoides sp. in Tachileik, the Mekong Region of Myanmar. The outcome of this study could be a useful index for the fish-borne zoonotic trematode epidemiology in the Mekong area. Besides, the results of our study contribute to filling the gap of information necessary for the control and prevention of fish-borne trematode zoonotic infections in the Mekong region

Biguanide-Based Synthesis of 1,3,5-Triazine Derivatives with Anticancer Activity and 1,3,5-Triazine Incorporated Calcium Citrate Nanoparticles

Twelve derivatives of biguanide-derived 1,3,5-triazines, a promising class of anticancer agent, were synthesised and evaluated for their anticancer activity against two colorectal cancer cell lines—HCT116 and SW620. 2c and 3c which are the derivatives containing o-hydroxyphenyl substituents exhibited the highest activity with IC50 against both cell lines in the range of 20–27 µM, which is comparable to the IC50 of cisplatin reference. Moreover, the potential use of the calcium citrate nanoparticles (CaCit NPs) as a platform for drug delivery system was studied on a selected 1,3,5-triazine derivative 2a. Condition optimisation revealed that the source of citrate ions and reaction time significantly influence the morphology, size and %drug loading of the particles. With the optimised conditions, “CaCit-2a NPs” were successfully synthesised with the size of 148 ± 23 nm and %drug loading of up to 16.3%. Furthermore, it was found that the release of 2a from the synthesised CaCit-2a NPs is pH-responsive, and 2a could be control released under the acidic cancer environment. The knowledge from this study is perceptive for further development of the 1,3,5-triazine-based anticancer drugs and provide the platform for the incorporation of other drugs in the CaCit NPs in the future