Papers by Keyword: Hydrogel

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Authors: Rui Jiang, Fang Zhang, Zhu Ping Yin, Shen Zhou Lu
Abstract: The availability of a safety and efficient vehicle for pain relief system remains major challenge. The clinical applications of capsaicin are restricted by lacking a long-term drug delivery system The purpose of the present study is to control the release of topically applied capsaicin from silk fibroin hydrogel, all factors including proportions of silk fibroin, amount of capsaicin and penetration enhancer are studied. The capsaicin release behavior was measured by using x-ray fluorescence spectroscopy (XRF). X-ray diffraction (XRD) was used to investigate structure of the silk fibroin hydrogels. The results indicate that the silk can protect the capsaicin and also all factors involved influence the capsaicin release behavior. The release of the capsaicin may be controlled exactly by changing the factors involved. So the silk fibroin hydrogels make the capsaicin a promising pain relief drug used in clinic in the future.
Authors: Nurul Nadiah Azmi, Ilya Izyan Shahrul Azhar, Jamaluddin Mahmud
Abstract: Skin is an important organ which provides multiple functions. Thus, if skin fails i.e. due to burns or diseases, body will lose the protection provided by skin against infections and the harmful outer environment. Due to that, synthetic skin is seen as a very important alternative in the future. A number of studies have been carried out to understand skin’s basic functions and behaviour as its mechanical properties and behaviour are important in various fields. Nevertheless, to date no breakthrough has been reported. Therefore, this paper aims to briefly review and outline a framework which ultimately will lead to the synthesising silicone-hydrogel materials that potentially becoming a skin substitute. The newly synthesised composite materials will be tested mechanically to characterise its behaviour based on Ogden hyperelastic model. It could be emphasised that the present study is significant and will contribute to the body of knowledge in the area of skin mechanics.
Authors: Yuan Zhou
Abstract: This paper was concerned with the effects of ultrasonication on the gelation behavior of silk fibroins (SF), and a comparison of Domestic and Wild silkworms was studied. The results show that: with the increase of ultrasonic power, the gelation time of domestic (Bombyx Mori) SF solution decreased sharply. But wild silkworms (Antheraea yamamai and Antheraea pernyi) SF were different, When the power of utrasonication was lower than 400-500 W, the velocity of gelation were accelerated, and when the ultrasonic power was higher than 400-500W, the gelation time were delayed. Whatever domestic or wild silkworms, the mechanism of the effects of ultrasonication on the gelation behavior was that the ultrasonication promoted the structural transformation of SF molecules from random coil or α-helix to β-sheet.
Authors: Chun Lei Jia, Wang Qun, Kai Tang
Abstract: A fast responsive thermosensitive hydrogel poly((N-isopropy- lacrylamide/Sodium acrylate) (P(NIPAm/AA-Na)) were prepared by free radical polymerization methods. The low critical soluble temperatures (LCST) of the hydrgols is about 60°C in 5%wt aqueous solutions. The heterogeneous macroporous structure was observed by SEM. Deswelling degree of the hydrogel is up to 75% in 60 seconds. The 1A rating wood stacking fire were suppressed with water, colloid extinguishing agent B of Zhejiang University and the thermosensitive P(NIPAm/AA-Na) hydrogel respectively. Radiant heat and the temperature were recorded by several heat probes and thermocouples during extinguishing. The results showed that the fire extinguishing-time of the thermosensitive hydrogel is shortest at the same practical rate of application among the three. Consumption of extinguishing agent is the least. The water damage to the section unfired is low after fire extinguishing. The extinguishing agent residual is easy to clean, so the extinguishing efficiency is high.
Authors: Xu An Cai, Hua Tong, Yu Zhao, Xin Yu Shen, Ji Ming Hu
Abstract: A new in situ precipitation technique was developed to promote high-affinity nucleation and growth of calcium phosphate in the polymer hydrogel. Gelatine/poly(acrylic acid)/hydroxyapatite (HA) composite has been prepared using template-driven reaction. Nano-sized hydroxyapatite particles were distributed within organic template homogenously, furthermore, inorganic particles were fine and uniform. During the composite process, 3D network of organic matrices and homogenous distributed nucleation sites played an important role in the superfine interaction of HA and hydrogel. This method provides an efficient approach toward inorganic/organic nanocomposites with high-uniformity decentralization for biomimetic replant applications. This paper discussed the mechanism of the reaction, and the concept of in situ precipitation in gel was brought forward.
Authors: Alvaro Antonio Alencar de Queiroz, José Carlos Bressiani, Ana Helena A. Bressiani, Olga Z. Higa, Gustavo Abel Abraham
Abstract: A novel bone scaffolding material was successfully fabricated by electrospinning from hyperbranched polyglycerol (HPGL) solutions containing nanoparticles of hydroxyapatite (HA). The potential use of the electrospun fibrous HPGL-HA scaffolds for bone regeneration was evaluated in vitro with human osteoblasts in terms of alkaline phosphatase (ALP) activity of the cells that were cultured directly on the scaffolds. The results were compared with those on corresponding HPLG-HA solution-cast film scaffolds. It was found that all of the fibrous scaffolds promoted much better adhesion and proliferation of cells than the corresponding film scaffolds.
Authors: Kui Lin Deng, Chun Yuan Huang, Xiao Bo Ren, Yu Bo Gou, Hai Bin Zhong, Peng Fei Zhang, Chun Yan Jiang
Abstract: A novel pH-sensitive poly (2-(acryloyloxy) propanoic acid) hydrogel (PAPA) synthesized from lactic acid by radical polymerization has been investigated in this work. The structure of prepared monomer 2-(acryloyloxy) propanoic acid) (APA) has been characterized by FTIR and 1H-NMR measurements. PAPA hydrogel demonstrated an obvious pH sensitivity in its swelling in the range of 4-7 pH of phosphate buffer solution (PBS). The rapid response of the hydrogel makes it suitable for drug delivery application. Here, salicylic acid (SA) selected as a model drug, the in-vitro drug release as a function of pH and temperature was studied systematically. The cumulative release of salicylic acid reached up to 86.6% in pH=7.4 PBS at 37.0°C within 550min. In pH=2.1 PBS, however, only 26.6% drug was released from the pH-sensitive PAPA on the same conditions.
Authors: Pierre Weiss, C. Vinatier, Jerome Guicheux, G. Grimandi, G. Daculsi
Authors: Qun Feng Liu, Bo Yuan, Xiao Feng Chen
Abstract: A kind of poly(N-isopropylacrylamide) (PNIPAM) gel was synthesized by radical polymerization of N-isopropylacrylamide monomer in the present of crosslinker N,N-Methylenebisacylamide using short reaction time. This kind of PNIPAM gel exhibits higher swelling ratio at low temperature and much faster deswelling rate than conventional gel, which could be attributed to the presence of loops, dangling chains and other incomplete structure in the gel caused by short reaction time.
Authors: Chun Lei Jia, Kai Tang
Abstract: A new attempt to suppress oil fire with a temperature-sensitive hydrogel was examed. The hydrogel were prepared by free radical polymerization methods with N-isopropy-lacrylamide (NIPAm) and Sodium acrylate (AA-Na). Different mass fractions of the aqueous hydrogen were measured by a differential scanning calorimeter (DSC) and viscosity tester. A series of gasoline fires were suppressed with hydrogel extinguishing agent B of Zhejiang University and the temperature-sensitive hydrogel respectively. The whole suppressing experiment was recorded by a digital video, four heat probes and eight thermocouples. It showed that the temperature-sensitive hydrogel has shorter extinguishment time and faster cooling rate than the hydrogel B, The extinguishing agent residual after the suppressing were observed by SEM, massive microporous structures were found in the temperature-sensitive hydrogel.
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