Polydimethylsiloxanes, 40-42 Protein

Silk (qv) suture is made from the threads spun by the silkworm Bombjx mori. The fiber is composed principally of the protein fibroin and has a natural coating composed of sericin gum. The gum is usually removed before braiding the silk yams to make sutures in a range of sizes. Fine silk sutures may be made by simply twisting the gum-coated silk yams to produce the desired diameter. White silk is undyed. Silk is either dyed black with logwood extract or blue with D C Blue No. 9. The suture may be uncoated or coated either with high molecular weight polydimethylsiloxane or with wax. 

Figure 15.4 Binding of bombykol to BmPBP at pH 7 as demonstrated by the cold-binding assay. After removal of the unbound ligand, bound bombykol was extracted from the ligated protein with a solid phase microextraction syringe (SPME, 65 pm polydimethylsiloxane divinylbenzene coating). Under the same conditions, but at low pH (5), the amount of ligand extracted is not significantly different from the amount extracted from a buffer solution (control).

Several polymers were evaluated in the form of a surface coating on glass beads packed in columns to determine their ability to retain platelets when whole human blood passes over the surface. This ability was measured as the platelet retention index p, the fraction of platelets retained on the column. Lowest values of p were found for poly(ethylene oxide), polypropylene oxide), poly(tetramethylene oxide) (in the form of polyurethanes), and polydimethylsiloxane. Highest values (around 0.8) were found for cross-linked poly(vinyl alcohol) and the copolymers of ethylenediamine with diisocyanates. Intermediate values were found for polystyrene and its copolymers with methyl acrylate, for polyacrylate, and for poly(methyl methacrylate). The results are interpreted in terms of possible hydrophobic and hydrogen bonding interactions with plasma proteins. 

Decamethylcyclopentasiloxane Dimethicone/mercaptopropyl methicone copolymer Dimethoxymercaptopropyl-terminated polydimethylsiloxane homopolymer (Mercaptopropyl) methylsiloxane-dimethylsiloxane copolymer PEG-8 isolauryl thioether hair creams/lotions Human placental protein hair dressing Corn (Zea mays) oil hair fixative, hair sprays VA/crotonates copolymer VA/crotonates/vinyl propionate copolymer hair fixative, setting lotions Sodium polystyrene sulfonate , VA/crotonates copolymer hair lacquer resin MDM hydantoin hair lotion Quassia hair perms Ammonium bisulfite... 

In addition to these organic syntheses, biochemical production of compounds in microreactors has also been performed. A microreactor array which enables high-throughput cell-free protein synthesis was developed [4]. The microreactor array is composed of a temperature control chip and a reaction chamber chip. The temperature control chip is a glass-made chip on which temperature control devices, heaters, and temperature sensors are fabricated with an indium tin oxide (ITO) resistive material. The reaction chamber chip is fabricated by micromolding of polydimethylsiloxane (PDMS)... 

In 2D cell culture on chip, cell adhesion has been extensively studied on patterned surfaces for it is critical to cellular functions. Micropattems have been used to study the cellular interactions with various materials such as metals, polymers, self-assembled monolayers, extracellular matrix proteins, cell adhesion peptides, and other bioactive molecules. The physical and chemical properties of a substrate affect the attachment and growth of cells on it, and many studies have demonstrated that different topographical features of a surface affect cell attachment. Glass, sflicon, and polydimethylsiloxane (PDMS) are widely used as substrate materials of ceU culture microchips. 

Geometrical lab chips with micropattemed surfaces are used to geometrically control the cell attachment to the matrix materials, which provide opportunities to explore the fundamental effect of geometrical-driven ceU morphology changes to stem cell differentiation. Microcontact printing techniques are widely used to pattern the shapes of individual cells on a substrate (Fig. 1). Briefly, the procedure involves the transfer of extracellular matrix proteins from the microfabricated polydimethylsiloxane (PDMS) stamp with micropattems onto the substrate. The nonpattemed... 

Surface block-graft-copolymerization, based on the photochemistry of N, AT-diethyldithiocarbamate has been applied to precisely design biocompatible and functional surfaces (patterns of immobilized heparin or proteins), as well as block-grafted surfaces on polystyrene [83]. Polystyrene surfaces have also been patterned by immobilization of poly(Af-isopropylacrylamide) by photolithography, and subsequently used for regiospecific cell attachment [84]. Surface modification of polydimethylsiloxane microfluidic devices by UV induced polymer grafting improved the stability of the electroosmotic mobility and improved electrophoretic resolution of peptides [85]. 

Cell-free protein synthesis was performed using polydimethylsiloxane (PDMS)-based microreactor arrays [22]. The microreactor array chip comprised a temperature control chip made of glass and a disposable reaction chamber chip made of PDMS. To evaluate the performance of this microreactor array, rat adipose-type fatty acid binding protein, glyceraldehyde-3-phosphate dehydrogenase, cyclophilin, and firefly luciferase were synthesized from their respective DNA templates using a cell-free extract prepared from Escherichia coli. 

Kang, I.K., Ito, Y., Sisido, M., and Imanishi, Y. (1988a) Adsorption of plasma proteins and platelet adhesion on to polydimethylsiloxane/poly(gamma-benzyl L-glutamate) block copolymer hlms. Biomaterials, 9,138-144. 

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