Photothermal Microfluidic Sensing Platform Using Near-Infrared Laser-Driven Multiplexed Dual-Mode Visual Quantitative Readout

Abstract

The application of different sensing principles in microfluidic devices opens up further possibilities for the development of point-of-care testing (POCT). Herein, the photothermal sensing principle is introduced in microfluidic paper-based analytical devices (μPADs) to develop a photothermal microfluidic sensing platform using near-infrared (NIR) laser-driven multiplexed dual-mode visual quantitative readout. Prussian blue (PB) as the analyte-associated photothermal agent was in situ synthesized in thermoresponsive poly­(N-isopropylacrylamide) hydrogels to serve as the on-chip photothermal sensing element. The NIR laser-driven photothermal effect of PB triggered not only on-chip dose-dependent heat generation but also phase transition-induced dye release from the hydrogels, simultaneously enabling both thermal image- and distance-based dual-mode visual quantitative readout of the analyte concentration in a multiplexed manner. Both the on-chip temperature elevation value of the hydrogels and the traveling distance of released dye solutions were proportional to the concentration of PB. With the detection of silver ions in environmental water as a proof-of-concept study, the photothermal μPAD can detect silver ions at a concentration as low as 0.25 μM with high selectivity and satisfactory accuracy. The photothermal microfluidic sensing platform holds great potential for POCT with promising integratability and broad applicability, owing to the combination of synergistic advantages of the photothermal sensing principle, μPADs, and photothermally responsive hydrogels.

Reagents-Loaded, Automated Assay that Integrates Recombinase-Aided Amplification and Cas12a Nucleic Acid Detection for a Point-of-Care Test

“…The automation of nucleic acid amplification, detection, and data readout is of great significance for improving the efficiency of genetic analysis. − The separate addition of various reagents of the RAA-Cas12a system is tedious in practical testing, so we attempt to mix all reagents and then add them into the reaction cells. At the same time, considering that the freeze-drying technology is beneficial to the maintenance of biomolecular activity, we plan to preload the mixed reagents of the RAA-Cas12a system into the 32 reaction cells of the chip (Figure a) by freeze-drying.…”

Advanced Signal-Amplification Strategies for Paper-Based Analytical Devices: A Comprehensive Review

“…The integration of the microfluidic platform with an intelligent sensing element is a novel strategy to compensate for the limitations of conventional microfluidic devices Recently, numerous advances in microfabrication techniques have been made, offering more facile and sensitive devices that possess many advantages over the conventional approaches. The microfluidic platform-based photothermal sensing assay is one of the currently emerging systems that hold great potential for paper-based point-of-care testing [102,105,106]. Microfluidic technologies have become increasingly powerful tools for developing point-of-care diagnostics because of their distinct advantages.…”

Plasmonically Modulated Gold Nanostructures for Photothermal Ablation of Bacteria

“…[269] To precisely monitor temperature at micro/nanoscale, thermal-responsive species are combined with nanostructured materials to develop different types of nanothermometers. [270] Typically, luminescent thermometers are designed and made based on the temperature-dependent properties, which include the emission intensity and/or lifetime of organic dyes, quantum dots and Ln 3+ ions, [271,272] the change of the aggregated states of hydrogels containing thermo-sensitive polymer, [273,274] and the color change via the transitions of crystal phase of liquid crystals. [275,276] In addition, other optical methods such as thermal reflection, absorption, Rayleigh scattering, Raman scattering and magnetic resonance imaging have also been developed for use in thermometry.…”