Arraying prostate specific antigen PSA and Fab anti-PSA using light-assisted molecular immobilization technology

We here report for the first time the creation of prostate specific antigen (PSA) and Fab anti-PSA biosensor arrays using UV light-assisted molecular immobilization (LAMI), aiming at the detection and quantification of PSA, a cancer marker. The technology involves formation of free, reactive thiol groups upon UV excitation of protein aromatic residues located in spatial proximity of disulphide bridges, a conserved structural feature in both PSA and Fab molecules. The created thiol groups bind onto thiol reactive surfaces leading to oriented covalent protein immobilization. Protein activity was confirmed carrying out immunoassays: immobilized PSA was recognized by Fab anti-PSA in solution and immobilized Fab anti-PSA cross-reacted with PSA in solution. LAMI technology proved successful in immobilizing biomedically relevant molecules while preserving their activity, highlighting that insight into how light interacts with biomolecules may lead to new biophotonic technologies. Our work focused on the application of our new engineering principles to the design, analysis, construction, and manipulation of biological systems, and on the discovery and application of new engineering principles inspired by the properties of biological systems.