Abstract
The immobilization of a capture molecule represents a crucial step for effective usage of gold nanoparticles in localized surface plasmon resonance (LSPR)-based bioanalytics. Depending on the immobilization method used, the resulting capture layer is of varying thickness. Thus, the target binding event takes place at different distances to the gold surface. Using the example of a C-reactive protein immunoassay, different immobilization methods were tested and investigated with regard to their resulting target signal strength. The dependency of the target signal on the distance to the gold surface was investigated utilizing polyelectrolyte bilayers of different thickness. It could be experimentally demonstrated how much the LSPR-shift triggered by a binding event on the gold nanoparticles decreases with increasing distance to the gold surface. Thus, the sensitivity of an LSPR assay is influenced by the choice of immobilization chemistry.
Highlights
The C-reactive protein (CRP) is an important biomarker for inflammation and infection of the human body[1,2,3,4]
Examples include the direct binding of CRP on anti-CRP antibodies-modified gold nanospheres[19], nanorods modified with single chain variable fragment[20], or silver nanoprisms modified with cytidine 5 ́-diphosphocholine (PC)[21]
These carboxyl groups were activated by incubation with EDC and NHS to form a NHS-ester[25], prior to incubation with the antibodies, which will bind via free amine groups to form a covalent amide b ond[26,27]
Summary
The C-reactive protein (CRP) is an important biomarker for inflammation and infection of the human body[1,2,3,4]. Several plasmonic nanoparticle-based methods are established in enzyme-linked immunosorbent assay (ELISA) platforms. The nanoparticle surface was modified with a self-assembling monolayer (SAM) of 11-Mercaptoundecanoic acid MUA (or mixed MUA layer with 1-octanethiol (1-OT) or 11-mercaptoundecanol (MUD)), attached by the thiol group to the AuNP, and exposing carboxyl groups (here called SAM method). These carboxyl groups were activated by incubation with EDC and NHS to form a NHS-ester[25], prior to incubation with the antibodies, which will bind via free amine groups to form a covalent amide b ond[26,27]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
