Phosphoric Acid Induced Controllable Nanoparticle Aggregation for Ultrasensitive SERS Detection of Malondialdehyde in a Microfluidic Chip

Malondialdehyde (MDA), one of the most important products lipid peroxidation, has been widely accepted as a biomarker to indicate food rancidity well progress some human diseases. However, ready detection MDA with ultra-high sensitivity remains challenge. In this work, microfluidic surface-enhanced Raman scattering (SERS) sensing chip based on phosphoric acid induced nanoparticles aggregation was proposed for ultrasensitive detection. The composed an ultrafast mixer, which efficiently transferred analytes hot spots via mixer assisted occupying (MAHSO) SERS strategy. Phosphoric acid, reagent used in detection, played role aggregator induce silver (Ag NPs); meanwhile, fast few milliseconds mixing time effectively prevented over-aggregation Ag NPs. Therefore, process generated uniform and dense substrate analyte molecules located spots. As result, possessed limit (LOD) lower than 3.3 × 10?11 M, high spot-to-spot uniformity relative standard deviation (RSD) 9.0% excellent batch-to-batch reproducibility RSD 3.9%. This method also demonstrated specificity reliability real sample recoveries 90.4–109.8% spiked tests.