There is an increasing need for highly sensitive and quantitative diagnostics at the point-of-care. The lateral flow immunoassay (LFA) is one of the most widely used point-of-care diagnostic tests; however, LFAs generally suffer from low sensitivity and lack of quantification. To overcome these limitations, thermal contrast amplification (TCA) is a new method that is based on the laser excitation of gold nanoparticles (GNPs), the most commonly used visual signature, to evoke a thermal signature. To facilitate the clinical translation of the TCA technology, we present the development of a TCA reader, a platform technology that significantly improves the limit of detection and provides quantification of disease antigens in LFAs. This TCA reader provides enhanced sensitivity over visual detection by the human eye or by a colorimetric reader (e.g., BD Veritor System Reader). More specifically, the TCA reader demonstrated up to an 8-fold enhanced analytical sensitivity and quantification among LFAs for influenza, malaria, and Clostridium difficile. Systematic characterization of the laser, infrared camera, and other components of the reader and their integration into a working reader instrument are described. The development of the TCA reader enables simple, highly sensitive quantification of LFAs at the point-of-care.
Bibliographical noteFunding Information:
FIND and London School of Tropical Medicine and Hygiene made the 3 malaria LFAs available for the study. Thanks to Dr. Steffen Rameil from R-Biopharm AG for his generous gift of RIDAQUICK Clostridium dif f icile GDH LFAs and control. We thank Ryan Halupnick who was an Assistant Scientist in Dr. Boulware’s lab for his help in designing and conducting the flu A dilution study. We also thank Wladislaw Scheychon who performed his master’s work on the reader component analysis. Finally, we thank Design Solutions, Inc. for the help in TCA box design and safety tests. We also thank the Minnesota Partnership for Biotechnology and Medical Genomics funding, a seed grant from the National Center for Advancing Translational Sciences of the National Institutes of Health (UL1TR000114) and a NSF CBET grant (1066343).