Potential of dendrimeric architecture in surface plasmon resonance biosensor

The aim of this paper is to study the effect of dendrimeric and non-dendrimeric support in surface plasmon resonance (SPR) sensors for proteineous antigen analysis. 11-mercapto undecanoic acid (MUA) linker was chosen to fabricate the non-dendrimeric sensor surface while fourth generation poly(amidoamine) (PAMAM) dendrimer was used to design the dendrimeric sensor support on gold disks. Both the surfaces were conjugated with human immunoglobulin G (HIgG) antibodies and the binding was monitored in real time on Autolab Twingle SPR system. Antibodies were covalently attached to the MUA surface using EDC-NHS chemistry while glutaraldehyde was used as linker to conjugate antibodies on MUA-PAMAM surface. Further, both the sensor supports were used to study the antigen-antibody interaction using goat anti-human immunoglobulin (GaHIgG) antigen as sample analyte. Through SPR measurements, we found that dendrimeric sensor support exhibited two fold enhanced signal for HIgG binding than that of MUA surface only. During GaHIgG interaction, dendrimer modified sensor surface displayed enhanced signal with respect to the non-dendrimeric surface. This enhanced sensor response of dendrimeric SPR sensor support is attributed to high functional group density, globular shape and greater accessibility of immobilized probe towards analyte interaction.