Browsing by Author "Jitlada Sansatsadeekul"

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    Characterization of associated proteins and phospholipids in natural rubber latex
    (2011-06-01) Jitlada Sansatsadeekul; Jitladda Sakdapipanich; Porntip Rojruthai; Mahidol University
    Non-rubber components present in natural rubber (NR) latex, such as proteins and phospholipids, are presumed to be distributed in the serum fraction as well as surrounding the rubber particle surface. The phospholipid-protein layers covering the rubber particle surface are especially interesting due to their ability to enhance the colloidal stability of NR latex. In this study, we have characterized the components surrounding the NR particle surface and investigated their role in the colloidal stability of NR particles. Proteins from the cream fraction were proteolytically removed from the NR latex and compare to those from the serum fractions using SDS-polyacrylamide gel electrophoresis revealing that both fractions contained similar proteins in certain molecular weights such as 14.5, 25 and 27kDa. Phospholipids removed from latex by treatment with NaOH were analyzed using 1 H-NMR spectroscopy and several major signals were assignable to -(CH 2 ) n -, -CH 2 OP, -CH 2 OC=O and -OCH 2 CH 2 NH-. These signals are important evidence that indicates phospholipids associate with the rubber chain. The colloidal behavior of rubber lattices before and after removal of protein-lipid membrane was evaluated by zeta potential analysis and scanning electron microscope (SEM). The lowest zeta potential value of NR particles was observed at pH 10, consequently leading to the highest stability of rubber particles. Additionally, SEM micrographs clearly displayed a gray ring near the particle surface corresponding to the protein-lipid membrane layer. © 2011 The Society for Biotechnology, Japan.
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    Molecular self assembly of mixed comb-like dextran surfactant polymers for SPR virus detection
    (2014-11-04) Katanchalee Mai-Ngam; Wansika Kiatpathomchai; Narong Arunrut; Jitlada Sansatsadeekul; Thailand National Metal and Materials Technology Center; Mahidol University; Thailand National Center for Genetic Engineering and Biotechnology
    The synthesis of two comb-like dextran surfactant polymers, that are different in their dextran molecular weight (MW) distribution and the presence of carboxylic groups, and their characterization are reported. A bimodal carboxylic dextran surfactant polymer consists of poly(vinyl amine) (PVAm) backbone with carboxyl higher MW dextran, non-functionalized lower MW dextran and hydrophobic hexyl branches; while a monomodal dextran surfactant polymer is PVAm grafted with non-functionalized lower MW dextran and hexyl branches. Layer formation of non-covalently attached dextran chains with bimodal MW distributions on a surface plasmon resonance (SPR) chip was investigated from the perspective of mixed physisorption of the bimodal and monomodal surfactant polymers. Separation distances between the carboxylic longer dextran side chains within the bimodal surfactant polymer and between the whole bimodal surfactant molecules on the chip surface could be well-controlled. SPR analysis of shrimp yellow head virus using our mixed surfactant chips showed dependence on synergetic adjustment of these separation distances. © 2014 Elsevier Ltd.
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    Origin of colloidal behavior of natural rubber particles
    (Mahidol University. Mahidol University Library and Knowledge Center, 2006) Jitlada Sansatsadeekul; Jitladda Sakdapipanich