A comparative study is reported regarding the use of two different surface plasmon resonance (SPR) biosensors, a
homemade SPR grating biosensor and a reference prism coupled biosensor, to perform quantification of C-reactive
protein (CRP) in human blood serum. Surface functionalization was conducted using anti-CRP fragments immobilized
directly on gold. Adsorption time optimization for the antibody fragments monolayer, non-specific binding (NSB)
resistance evaluation and CRP detection were conducted, with better results achieved by the grating biosensor on all
topics, namely less functionalization time, higher resistance to NSB and wider CRP dynamic concentration range. A
study regarding comparison between continuous flow and surface coating immobilization is also reported in this work.
We have shown that surface coating immobilization achieves similar NSB resistance and CRP detection results, allowing
a 75% assay cost reduction by lower solution volume requirement. Results suggest that the coating immobilization
technique is the best suited to be used in further studies in order to obtain a viable immunosensor for CRP and other
biomarkers detection in complex biological fluids.