Turbidimetric inhibition immunoassay revisited to enhance its sensitivity via an optofluidic laser

• Published in: Biosensors & bioelectronics Vol. 131; pp. 60 - 66
• Main Authors: Yang, Xi, Shu, Wenxiong, Wang, Yanqiong, Gong, Yuan, Gong, Chaoyang, Chen, Qiushu, Tan, Xiaotian, Peng, Gang-Ding, Fan, Xudong, Rao, Yun-Jiang
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15-04-2019
• Subjects: Antigen-antibody complexes; Biomarker detection; Laser dye; Optofluidic laser; Turbidimetric inhibition immunoassay; Optofluidic laser; Biomarker detection; Laser dye; Turbidimetric inhibition immunoassay; Antigen-antibody complexes
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2019.02.013

Turbidimetric inhibition immunoassay (TIIA) is a classic immunodiagnostic method that has been extensively used for biomarker detection. However, the low sensitivity of this technique hinders its applications in the early diagnosis of diseases. Here, a new concept, optofluidic laser TIIA (OFL-TIIA), is proposed and demonstrated for sensitive protein detection. In contrast to the immunoreaction in traditional TIIA, in which the single-pass laser loss is detected, the immunoreaction in the OFL-TIIA method takes place in a laser cavity, which considerably increases the loss induced by antigen-antibody complexes (AACs) via the amplification effect of the laser. A commercial IgG TIIA kit was selected as a demonstrative model to characterize the performance of OFL-TIIA. A wide dynamic range of five orders of magnitude with an exceptional limit of detection (LOD) (1.8 × 10−10 g/L) was achieved. OFL-TIIA is a fast, sensitive, and low-cost immunoassay with a simple homogeneous and wash-free process and low-volume sample consumption, thus providing a new detection platform for disease diagnostics.
•Optofluidic laser turbidimetric inhibition immunoassay is demonstrated.•OFL-TIIA performs sensitive protein detection with a large dynamic range.•OFL-TIIA enables fast, wash-free and homogeneous immunoassay.