Silver mirror films deposited on well plates for SERS detection of multi-analytes: Aiming at 96-well technology

Abstract

96-Well technology is associated with automated sample preparation and simultaneous analysis based on the low-cost well plate format. To explore the potential applications of 96-well technology in SERS detection, we examined the surface-bound electroless deposition procedure for the preparation of uniform and stable Ag mirror films on polydopamine (PDA)-coated well plates as active-SERS substrates. In the presented procedure, small Ag seeds assembled on PDA coating were employed as the surface-bound catalyst and provided the active sites for electroless Ag deposition. The high-quality Ag mirror films showed high performance in terms of sensitivity, uniformity, reproducibility and stability using rhodamine 6G (R6G) as the probe molecule. A remarkable enhancement factor of 3.41 × 108 was obtained. The relative standard deviations against well-by-well and batch-by-batch reproducibility were less than 5%. The SERS films on well plates were successfully used to quantify the amounts of organic dyes (R6G and malachite green) in environmental water samples and small biological molecules (adenosine triphosphate and adenine) in urine matrix, displaying satisfactory sensitivity, selectivity and recovery. Their limit of detection values were at nanomolar, even picomolar concentration.