A new lateral flow plasmonic biosensor based on gold-viral biomineralized nanozyme for on-site intracellular glutathione detection to evaluate drug-resistance level.

Temozolomide (TMZ)-resistant glioblastoma multiforme (GBM) cells would have abnormal redox status due to bio-thiols, like glutathione (GSH), which constitute the most crucial defense system that protects cells from therapeutic agents. Current strategies for GSH detection often require sophisticated instruments that may not be available in laboratories with fewer resources. Here, we circumvent this problem by introducing a lateral flow plasmonic biosensor (LFPB) based on gold-viral biomineralized nanoclusters (AuVCs) as nanozymes that enables the detection of a few molecules with the naked eye and quantified by an auto-analysis software. The GSH level controls the growth of gold nanoparticles (AuNPs) and generates coloured patterns with distinct tonality, which are then auto-analyzed to calculate the GSH concentrations by smartphone with an auto-analysis software. Under the optimized conditions, grayscale value plotted against GSH concentration exhibited a linear relationship within the range of 25-500 μM with a limit of detection (LoD) of 9.80 μM and highly positive correlation between detected GSH level and TMZ drug-resistance level in GBM cells. This excellent property allowed our approach to be used for on-site determination of GSH levels in a rapid (i.e., within 30 min), simple (i.e., auto-analysis software), and cost-effective process (i.e., instrument-free) for cancer precision therapy.