Abstract: Surface plasmon resonance(SPR) absorption and imaging(SPRI) have been explored for screening and differentiating glycoproteins from non-glycoprotein according to the shift of maximum SPR absorption and/or to the variation of picture gray intensity. In combination with competitive washing with sugar solutions, SPRI has the ability to produce different signals for different gylcoproteins, offering a potential way to identify these gylcoconjugates. To conduct SPR and SPRI, proteins(at 1.0 mg/mL), in stead of lectins, were immobilized on gold sensing films to reduce the use of the costly glycoproteins. The sensing film was fixed in a laboratory-established SPR or SPRI system, equilibrated with 50 mmol/L Tris-HCl at pH=7.4 at a flow rate of 20 μL/min, reacted with 200 nmol/L ConA(prepared in the Tris-HCl solution containing 120 mmol/L NaCl, 25 mmol/L CaCl2 and 5 mmol/L MnCl2) at room temperature for 1 h and rewashed with Tris-HCl solution. For competitive washing, 80 mmol/L glucose solution was pumped into the analytical cell and reacted for 1 h. The signals were recorded whenever necessary. Non-gylcoproteins had no signals when using either SPR or SPRI while glycoproteins gave different SPR shifts and gray intensity in SPRI.

Key words: Glycoprotein, Protein microarray, Surface plasmon resonance imaging(SPRI)