Scheme 1

Schematic representation of rapid visualization of latent fingermarks by Au seed-mediated enhancement technique. Lysozyme-binding aptamer-conjugated Au NPs specifically recognize and target lysozyme in latent fingermarks (step 1). After treating with Au⁺-complex solution (step 2), bigger Au NPs with visible color are produced from Au seeds and can be clearly seen with the naked eye within 3 min. The total process from fingermarks collection to visualization can be completed within 10 min