Immunological Multimetal Deposition for Rapid Visualization of Sweat Fingerprints†
This work was supported by the National Natural Science Foundation of China (21222504, 21335001), the Zhejiang Provincial Natural Science Foundation (R14B050003), the Program for New Century Excellent Talents in University, and the Fundamental Research Funds for the Central Universities (2014XZZX003-04).
Graphical Abstract
With bare eyes: The detection of latent fingerprints and biomolecules that are secreted by human eccrine sweat glands is possible by immunological multimetal deposition (iMMD). In this approach, gold nanoparticles serve as the nucleation sites for autometallographic deposition of silver particles from the silver staining solution and as the carriers of recognition molecules.
Abstract
A simple method termed immunological multimetal deposition (iMMD) was developed for rapid visualization of sweat fingerprints with bare eyes, by combining the conventional MMD with the immunoassay technique. In this approach, antibody-conjugated gold nanoparticles (AuNPs) were used to specifically interact with the corresponding antigens in the fingerprint residue. The AuNPs serve as the nucleation sites for autometallographic deposition of silver particles from the silver staining solution, generating a dark ridge pattern for visual detection. Using fingerprints inked with human immunoglobulin G (hIgG), we obtained the optimal formulation of iMMD, which was then successfully applied to visualize sweat fingerprints through the detection of two secreted polypeptides, epidermal growth factor and lysozyme. In comparison with the conventional MMD, iMMD is faster and can provide additional information than just identification. Moreover, iMMD is facile and does not need expensive instruments.
