sample cassette Laser or LED CCD camera or photo diode array display digital window sample holder prism polarizer lens disposable sensor chip cover plate Compact SPR Biosensor

For the sample with low concentration, signal shift might be smaller than environmental drift change. Self-referencing eliminates influence by environment (excellent robustness against temperature and buffer change). substrate PDMS flow cell analyte x y z Top view Self-referencing SPR

Experimental procedure glass slide Au substrate PDMS micro flow cell Top view Side view width: 50 – 300 μm for channels and spaces between channels Step 1 Step 2 Step 3 substrate PDMS flow cell x y z channel width: 500 μm – 1 cm glass slide Au solution

Multi-step functionalization procedure using mouse IgG as reference glass slide Au sensing area referencing area MUA antigen mouse IgG glass slide Au antibody glass slide Au glass slide Au Taya, figs for pat appl, Aug 2005, fr Fengyu REV Aug 30.ppt

pbs mouse IgG 100  g/ml (a) (b) (c) (d) image pixel number y axis of sensor chip Mouse IgG absorption onto the gold surface

(a) (b) (c) (d) image pixel number y axis of sensor chip Anti-CEA antibodies immobilized onto sensor chip

TKH2 20  g/ml STn 100 ng/ml sensing (1) referencing (2) (1) - (2) sensing (1) referencing (2) (1) - (2) (a) (b) Sensorgrams of TKH2 antibodies immobilizing onto sensor chip and STn antigens binding to TKH2 antibodies

sensing (1) referencing (2) (1) - (2) CEA 10 ng/ml anti-CEA antibody 20  g/ml sensing (1) referencing (2) (1) - (2) (a) (b) Sensorgrams of anti-CEA antibodies immobilizing onto sensor chip and CEA antigens binding to antibodies