Electrochemical Dual-Sensing Platform for HLA-B*13:01 Detection to Prevent Severe Cutaneous Adverse Reactions (SCARs) Induced by Dapsone and Cotrimoxazole

The HLA-B*13:01 allele is a critical biomarker for dapsone- and cotrimoxazole-induced severe cutaneous adverse reactions (SCARs). Overcoming the limitations of centralized laboratory screening, we developed a portable electrochemical dual-sensing platform (EDP) for the simultaneous, ultrasensitive detection of HLA-B*13:01 alongside a TIMP-1 internal control. On screen-printed carbon electrodes (SPCEs), TIMP-1 is captured through robust biotin-streptavidin interactions, while HLA-B*13:01 relies on sequence-specific ssDNA hybridization. Crucially, the system utilizes methylene blue (MB) to precisely modulate both electrostatic repulsion and physical steric hindrance, enhancing signal discrimination. The platform demonstrates exceptional limits of detection, reaching 0.992 pg and 65.5 fg when evaluated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), respectively. Notably, accounting for genomic copy number, this corresponds to a practical detection limit of ∼3 HLA-B gene copies (1 × 10-2 ng genomic DNA), several orders of magnitude below conventional gel electrophoresis. Validated against 100 blinded clinical samples, the EDP achieved 100% sensitivity, specificity, and accuracy using ROC-derived cut-offs. By delivering a highly scalable, portable post-PCR screening tool, this work provides a high-performance alternative to standard methods, effectively mitigating SCAR risks and advancing the global accessibility of precision medicine.