A dual-mode colorimetric/photothermal lateral flow biosensor based on Au/Ti₃C₂T_X for HIV-DNA detection

Traditional lateral flow biosensors (LFBs), which utilize colorimetric signals as output, possess the virtues of simplicity and rapidity. However, it also suffers from insufficient sensitivity and limited reliability. It is well known that the results of LFBs can be false positive, and it is difficult to perform accurate quantification under low-abundance targets. In recent years, researchers have continued to apply new nanomaterials to LFBs to obtain more sensitive detection performance and multiple signal output modes.

Herein, taking advantage of its excellent color intensity and photothermal properties, we synthesized a dual-functional Au/Ti₃C₂T_X nanocomposite material by loading Au nanoparticles (Au NPs) on Ti₃C₂T_X via the one-step self-reduction method, in which process Ti₃C₂T_X acted as both reducing agent and carrier at the same time. Based on the prepared material, a colorimetric/photothermal dual-mode LFB was constructed for the detection of human immunodeficiency virus (HIV) DNA. In this work, the Au/Ti₃C₂T_X nanocomposite served as a dual-signal label on the LFB platform for the first time. As a colorimetric label, Au/Ti₃C₂T_X achieved signal amplification owing to abundant Au NPs loaded on Ti₃C₂T_X. When playing the role of a photothermal label, the excellent photothermal effect of Au/Ti₃C₂T_X contributed to a low limit of detection down to 0.01 nM target in human serum.

Au/Ti₃C₂T_X served as a dual-signal label on the LFB platform for the first time and showed extremely dependable analytical performance. Furthermore, this work offered a novel versatile dual-mode point-of-care testing platform in the fields of food safety, clinical diagnosis, and environmental monitoring.