正在加载图片...
Recognitive molecular systems Polymer surfaces in contact with biological fluids,cells,or application and environm ace pa an,1996 121 190U 1873 U-HEPTA Figure 7.Scanning electron micrograph of lactic gly- Was leveloped (Byrne et al colic aci copolymer fibers. racietsoftheetmqee ecoeniofordgd ation of cartilage.The approach has been widely studied to The polymers.Thesen → Nanotechnology and microfabrication Cartilage Tissue Engineering 树-模 Figure 9.Configurational biomimetic imprinting pro BEFORE (C)The the net (F)in Figure 8.Polymer scaffold in the for m of a human nose (co sy,Prasad 2998 December 2003 Vol.49.No.12 AIChE Journal Figure 7. Scanning electron micrograph of lactic gly￾colic acid copolymer fibers. ation of cartilage. The approach has been widely studied to create a variety of tissues in animal studies such as blood vessels, bone, and urologic structures Vacanti and Langer, Ž 1999 . A number of new polymers are being synthesized for . the purposes of improving cellular specificity. An example is the synthesis of polylactic acid-co-lysine polymers. These en￾able the attachment of specific amino acid sequences through the carboxyl group of the lysine via a carbodiimide Barrera Ž et al., 1993 .. Nanotechnology and Microfabrication In recent years we have seen an explosion in the field of novel microfabricated and nanofabricated devices for drug delivery. Such devices seek to develop a platform of well con￾trolled functions in the micro- or nanolevel. They include: iŽ . Recognitive molecular systems; and ii Microfabrication and Ž . microelectronic devices. Figure 8. Polymer scaffold in the form of a human nose ( ) courtesy, Prasad Shastri . Recogniti©e molecular systems Polymer surfaces in contact with biological fluids, cells, or cellular components can be tailored to provide specific recog￾nition properties or to resist binding depending on the in￾tended application and environment Schakenraad et al., Ž 1996 . Engineering the molecular design of biomaterials by . controlling recognition and specificity is the first step in coor￾dinating and duplicating complex biological and physiological processes Peppas and Langer, 1994 . The design of surfaces Ž . for cellular recognition and adhesion, analyte recognition, and surface passivity encompasses a number of techniques such as surface grafting ultraviolet radiation, ionizing radiation, Ž and electron beam irradiation Ratner and Hoffman, 1996; . Ž Thom et al., 2000 . Certain techniques can change the chemi- . cal nature of surfaces and produce areas of differing chem￾istry, as well as surfaces and polymer matrices with binding regimes for a given analyte. In recent years a novel technique of configurational biomimesis was developed Byrne et al., Ž 2002 . The main characteristics of the technique are shown in . Figure 9. Such techniques can generate novel biomimetic ma￾terials mimicking biological recognition for drug delivery, Ž . drug targeting, and tissue engineering devices. The synthesis and characterization of configurational biomimetic gels and molecularly imprinted drug release and protein delivery sys￾Figure 9. Configurational biomimetic imprinting pro￾cess. Ž . Ž. A Solution mixture of template, functional monomer s Ž . triangles and circles , crosslinking monomer, solvent, and initiator I . B The pre-polymerization complex is formed Ž. Ž . via non-covalent chemistry. C The formation of the net- Ž . work. D Wash step where original template is removed. Ž . Ž. Ž. E Rebinding of template. F In less crosslinked systems, movement of the macromolecular chains will produce areas of differing affinity and specificity filled molecule is isomer Ž of template Courtesy: M. Byrne. . 2998 December 2003 Vol. 49, No. 12 AIChE Journal
<<向上翻页向下翻页>>
©2008-现在 cucdc.com 高等教育资讯网 版权所有