Optofluidic laser immunosensor for rapid and ultrasensitive dual biomarker detection

With the development of medical laboratory science, sensitive biomarkers detection has a prime role in the early diagnosis of diseases. The rapid diagnosis is crucial in acute diseases to lower mortality, e.g., acute myocardial infarction (AMI). Additionally, the dual-biomarker detection is highlighted in the bioassays. Compared to the gold standard immunoassay—enzyme-linked immunosorbent assay (ELISA) with extensive pretreatment and extended duration, the turbidimetric inhibition immunoassay (TIIA) is an ideal candidate for the fast detection with simple procedure and short reaction time. However, the low sensitivity limits its applications. Here, we presented an optofluidic laser immunosensor based on the latex-enhanced TIIA. With the dual-amplification of latex particles and laser, a fast and sensitive detection of cardiac troponin I (cTnI) was achieved. Furthermore, a dual-biomarker immunoassay was demonstrated with the optofluidic laser immunosensor by a two-step strategy to produce two types of immune complexes in the optofluidic laser. With the low minimum distinguishable detection (~fM) of dual-biomarkers of cTnI and immunoglobulin G (IgG) was achieved by the two-step strategy within 25 min. Thanks to the various commercial immunoassay kits, this method shows the potential to be employed in immunoassays for a variety of proteins, providing a unique platform for rapid and ultrasensitive dual-biomarker biosensing and an effective tool for clinical diagnosis of diseases.