Multidimensional Fingerprint Analysis

Latent fingerprints (LFPs) provide unique ridge patterns, chemical, biological, and temporal information, which is particularly valuable for challenging impressions (e.g., overlapping LFPs) where minutiae are insufficient for identification. However, conventional development methods often prioritize physical morphology, forcing a compromise between preserving ridge details and downstream forensic intelligence analysis. To address this limitation, we propose an integrated triple strategy synergizing the ink-labeled method, scanning electrochemical microscopy (SECM), and short tandem repeat (STR) genotyping via a flexible polyvinylidene fluoride (PVDF) membrane to obtain high-resolution physical morphology, enhanced electrochemical image, DNA profile and deposition sequences within a single LFP. The ink-labeled method exploits wettability differences to visualize levels 1∼3 ridge features, while SECM leverages the conductivity of ink to further enhance imaging resolution for reliable sweat pore detection. Notably, the temporal decrease in ridge current enables the determination of the deposition sequence of overlapping fingerprints with 6 h intervals that cannot be resolved by optical visualization. Crucially, the PVDF membrane facilitates sampling and preservation of touch DNA, which is compatible with DNA genotyping. The subsequent STR analysis yields a high allele detection rate (>90%) even after SECM imaging for 30 min, with DNA transfer efficiency comparable to that of the standard swab method, indicating good compatibility between SECM imaging and downstream DNA analysis. The strategy’s feasibility was further demonstrated using fingerprints deposited on PVDF membranes and book-cover substrates. In all, this minimally destructive strategy provides a promising platform for comprehensive fingerprint analysis while preserving its integrity, thereby strengthening the power of fingerprint evidence.