Tham khảo tài liệu 'biosensors emerging materials and applications part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 112 Biosensors - Emerging Materials and Applications Fig. 8. Time trace of cantilever defections resulting from the binding of enantiomers of amino acids to micro cantilevers modified with covalently anti-L-amino acid antibody 1-4 or human immunoglobulin G 5 6 1-50 mg L L-tryptophan 2 5- 50mg L L-phenylalanine 3- 50 mg L D-tryptophan 4 6- 50 mg L D-phenylalanine. Dutta et al. 2003 . These antibodies have been also employed for enantioselective sequential-injection chemiluminescence immunoassay of triiodothhyronine and tetraiodothyronine with immunoreactor with immobilized haptens. It has been shown that the detection of of the L enantiomers in samples of D enantiomers is possible in less than 5 minutes including regeneration of immunoreactor Silvaieh et al. 2002 . Anti-D-AA was used in microfabricated cantilevers for enantioselective detection of amino acids based on inducing surface stress by intermolecular forces arising from analyte adsorption on surface-immobilized antibodies Dutta et al. 2003 . The temporal response of the cantilever allowed the quantitative determination of enantiomeric purity up to an enantiomeric excess of . Based on the slope of response curves or anti-D-amino acid antibody the selectivity coefficients for D- enantiomer towards L-isomer were and for D-phenylalanine D-tryptophan Fig 8. and D-methionine respectively. The largest enantioselectivity has been observed for D-valine 104 . 4. Enantioselective bioreceptors Mass-based biosensors There are many examples of sensors exhibiting the enantioselective properties based on quartz crystal microbalance technique for example sensor for L-histidine Zhang Z. et al. 2005 methyl lactate Ng et al. 2002 L-cysteine Chen Z. et al. 2000 L-phenylalanine Huang et al. 2003 or - menthol Tanese et al. 2004 . However the combination of biological macromolecules and QCM technique has been rarely reported for the studies of chiral discrimination. Two sensors were developed by .
