Enhancement assays require the use of two binding partners. Capture receptors (RC) are fixed onto the unclad optical fiber while detection receptors (RD) are bound to the AuNPs. During a sensing event, RD-functionalized AuNPs are introduced to the RC-functionalized sensing surface with the target analytes (A). AuNPs are brought to the sensing surface through formation of sandwich-like RD-A-RC complexes. Presence of AuNPs at the sensing surface results in a dramatic optical response.
Target: procalcitonin (PCT) in serum
Septicemia is a life-threatening condition caused by bacterial infection of the blood. This may lead to sepsis, a serious complication that causes inflammation throughout the body, resulting in blood clots to cause organ failure. Procalcitonin (PCT) is a biomarker that can specifically diagnose septicemia and measure its severity with high accuracy.
Anti-PCT capture antibodies are immobilized onto the sensing surface while anti-PCT detection antibodies are functionalized onto the AuNPs. During detection, presence of PCT results in formation of sandwich-like antibody-antigen-antibody-AuNP conjugates at the sensing surface.