Aryl Diazonium for Biomolecules Immobilization onto SPRi Chips

• Published in: Chemphyschem Vol. 10; no. 18; pp. 3273 - 3277
• Main Authors: Mandon, Céline A., Blum, Loïc J., Marquette, Christophe A.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 21.12.2009; WILEY‐VCH Verlag; Wiley; Wiley-VCH Verlag
• Subjects: Animals; Biochemistry; Biochemistry, Molecular Biology; Biological and medical sciences; Cattle; Chemistry; diazo compounds; Diazonium Compounds - chemistry; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General and physical chemistry; Immobilized Proteins - chemistry; Life Sciences; microarrays; Molecular biophysics; Physico-chemical properties of biomolecules; protein immobilization; Serum Albumin, Bovine - chemistry; Staphylococcal Protein A - chemistry; Surface physical chemistry; Surface Plasmon Resonance; thioctic acid; Self assembly; Monolayer; Atomic force microscopy; Modification; thioctic acid; Surface chemistry; Immobilization; Surface plasmon; Protein; microarrays; Characterization; Regeneration; Acids; Technology; surface plasmon resonance; Imaging; protein immobilization; Diazo compound; Resonance; Aryl; Diazonium compounds; diazo compounds; Deposition
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.200900599

A method for the immobilization of proteins at the surface of surface plasmon resonance imaging (SPRi) chips is presented. The technology, based on the electro‐deposition of a 4‐carboxymethyl aryl diazonium (CMA) monolayer is compared to a classical thioctic acid self‐assembled monolayer. SPRi live recording experiments followed by the quantification of the diazonium surface coverage demonstrate the presence of a monolayer of electro‐deposited molecules (11*1012 molecules mm−²). This monolayer, when activated through a classical carbodiimide route, generates a surface suitable for the protein immobilization. In the present study, protein A and BSA are immobilized as specific and control spots (150 μm id), respectively. The AFM characterization of the spots deposited onto CMA or thioctic acid modified chips prove the presence of 4.7 nm protein monolayers. Finally, the SPRi detection capabilities of the two surface chemistries are compared according to specific signal, non‐specific interaction and regeneration possibilities. Advantages are given to the CMA surface modification since no measurable non‐specific signal is obtained while reaching a higher specific signal. Protein immobilization: Electro‐grafting of a 4‐carboxymethyl aryl (CMA) diazonium monolayer for the immobilization of protein arrays onto SPRi chips (see figure) complements the preexisting thiol and dextran immobilization approaches. The CMA modified SPRi chips exhibit low non‐specific binding of protein, high SPRi specific response and regeneration potentialities.