Papers by Author: Seeram Ramakrishna

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Authors: Yi Xiang Dong, Susan Liao, Seeram Ramakrishna, Casey K. Chan
Abstract: Biodegradable nanofiber has become a popular candidate as tissue engineering scaffolds due to its biomimic structure as natural extracellular matrix (ECM). Certain tissue regeneration may require prolonged in vitro culture time for cellular reorganization and tissue remodeling. Therefore, long term understanding of cellular effects on scaffold degradation is needed. Although there are some degradation studies on nanofiber, degradation study of nanofibers with cell culture is rare. In our study, polyglycolide (PGA), poly(DL-lactide-co-glycolide) (PLGA), poly(L-lactide-co-ε- caprolactone) [P(LLA-CL)] were electrospun into nanofiber scaffolds. The scaffolds were cultured with porcine smooth muscle cells (PSMC) for up to 3 months to evaluate their degradation behavior and cellular response. The results showed that their degradation rates were in the order of PGA>>PLGA>P(LLA-CL). PGA nanofiber degraded in 3 weeks and only supported cell growth in the first few days. Cell culture accelerated the surface erosion of PLGA and P(LLA-CL) nanofiber while the bulk degradation remained unaffected. Furthermore, the cell culture did not significantly reduce the mechanical strength of PLGA and P(LLA-CL) during degradation.
Authors: A. Jaworek, A. Krupa, A.T. Sobczyk, M. Lackowski, T. Czech, Seeram Ramakrishna, S. Sundarrajan, Damian Pliszka
Abstract: The paper presents experimental results of electrospray deposition of nanopowder onto microfibers. The process is designed to form fibrous filters with an enhanced collection efficiency in the submicron range by covering the fabric with a catalytic material. Polyamide fibres were coated with Al2O3, ZnO, MgO, or TiO2 nanoparticles. The structures obtained were porous at the nanometer scale which increased the total surface area of the catalyst.
Authors: Damian Pliszka, S. Sundarrajan, A. Jaworek, A. Krupa, M. Lackowski, Seeram Ramakrishna
Abstract: We present a novel method of using Particle Image Velocimetry in electrospraying process studies. Electrospraying of metal oxides nanoparticles and covering nonwoven nanofiber mat creates composite material for potentially wide applications. Precise control of the electrospinning process gives possibility for better control of nanoparticles deposition and thereby enhancing its relative properties.
Authors: Check Shyong Quek, Norzita Ngadi, Muhammad Abbas Ahmad Zaini, Seeram Ramakrishna
Abstract: The natural hollow fiber, namely kapok, has been studied for the removal of oil, particularly in the area of oil spill clean-up. The hydrophobic nature of the natural absorbent has been demonstrated to exhibit (or show potential to exhibit) excellent oil absorption properties. Kapok fiber is inexpensive, readily available, very lightweight which makes it easy for transportation and its excellent buoyancy eases retrieval. Reusability of the material up to 15 cycles has been reported and this supports its being environmental-friendly. This paper looks into the oil absorption capacity of raw kapok fiber that can be dramatically enhanced by the simple mechanism of stirring. The oil absorption capacity is greatly increased to more than 200 times the mass of kapok used, i.e., with stirring, 1 g of the kapok fiber is able to absorb at least 200 g of the oil (200 g/g) which in this case is the refined palm oil used for cooking. The paper also discusses the reasons for the improvement due to stirring. And as a natural agricultural product which is abundant, besides being environmental-friendly, its application would be a sustainable approach to control water pollution due to oil spills and industrial organic contaminants.
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