This article highlights recent signal amplification techniques for enhancing the detection sensitivity of colorimetric lateral flow assay.

Supramolecular hydrogels with rapid self-healing ability were fabricated through the strong host–guest interaction between β-cyclodextrins in a host polymer and carboranes in a guest polymer.

Rapid and sensitive diagnostics of infectious diseases is an urgent and unmet need as evidenced by the COVID-19 pandemic. Here, we report a strategy, based on DIgitAl plasMONic nanobubble Detection (DIAMOND), to address this need. Plasmonic nanobubbles are transient vapor bubbles generated by laser heating of plasmonic nanoparticles (NPs) and allow single-NP detection. Using gold NPs as labels and an optofluidic setup, we demonstrate that DIAMOND achieves compartment-free digital counting and works on homogeneous immunoassays without separation and amplification steps. DIAMOND allows specific detection of respiratory syncytial virus spiked in nasal swab samples and achieves a detection limit of ~100 PFU/mL (equivalent to 1 RNA copy/µL), which is competitive with digital isothermal amplification for virus detection. Therefore, DIAMOND has the advantages including one-step and single-NP detection, direct sensing of intact viruses at room temperature, and no complex liquid handling, and is a platform technology for rapid and ultrasensitive diagnostics.

A seed-mediated method was developed for the synthesis of Cu-based heterostructured and alloyed nanocrystals, and the heterostructured and alloyed CuGaS₂nanocrystals showed enhanced photocatalytic activities toward hydrogen production by water splitting.