A next-generation SPE-enabled microfluidic device for the rapid screening of antibiofilm compounds.

The urgent need for new antibiofilm agents has led to large-scale compound screening, commonly using microtiter plate (MTP) assays. Although simple and high-throughput, MTP methods rely on static conditions, provide mainly 24-h endpoint data, and do not reveal the antibiofilm activity at specific biofilm stages. This study introduces an SPE-enabled microfluidic platform with real-time electrochemical impedance spectroscopy to enable dynamic, stage-wise evaluation of antibiofilm activity against S. aureus, C. albicans, and polymicrobial biofilms. MTP assays showed a substantial reduction in biomass at 24th hour, with absorbance values declining from 0.10427 to 0.06177 (S. aureus), 0.11451 to 0.04967 (C. albicans), and 0.19 to 0.05383 (polymicrobial) for QRC. The SPE-enabled microfluidic system facilitated continuous, time-dependent observation of biofilm progression. In untreated S. aureus, impedance increased from 355.81 Ω (0 h) to 376.31 Ω (6 h), 455.67 Ω (12h), 548.56 Ω (18 h), and peaked at 677.28 Ω (24 h), showing biofilm maturation, followed by a decline to 492.96 Ω (30h), due to cell dispersion. In contrast, Quercetin-treated S. aureus, rather than growth, showed continuous decline in impedance from the 6th hour through the 30th hour (299.98 → 256.00 → 159.26 → 92.64 → 90.48 Ω). The observed decline demonstrates Quercetin's antibiofilm activity. The impedance-based analysis highlighted distinct biofilm life-cycle dynamics that standard evaluations couldn't detect. This study shows that the SPE-enabled microfluidic platform is more reliable and adaptable than MTP assays for rapid antibiofilm assessment and translational screening of potential therapeutics due to its higher time resolution, physiological relevance, and sensitivity.