The compatibility of immunolabeling with STR profiling

Abstract

Immunolabeling is a technique, which has recently been introduced to enhance the quality of developed fingermarks and subsequently strengthen the evidential value. The effect of this method on subsequent DNA analysis, however, has not been explored yet. Therefore, the current pilot study aimed to determine whether STR profiling is possible after immunolabeling. Since immunolabeling involves washing steps which could reduce DNA quantities, the use of different fixatives including methanol, formaldehyde and universal molecular fixative (UMFIX) were investigated. STR profiles from the (immunolabeled) fingermarks were generated after four days and four weeks by a direct PCR method to enable comparison of relatively fresh and old fingermarks. The fingermarks were deposited on diverse forensically relevant substrates, including glass, metal and tile. STR profiles could be recovered for all tested fixatives with no significant difference in performance. However, the mean number of detected alleles was the highest when methanol was used for fixation. Furthermore, immunolabeling on aged fingermarks (4 weeks) was also possible, but the number of detected alleles showed a non-significant decrease. DNA could be recovered from deposits on all substrates, of which glass showed the highest mean number of detected alleles followed by metal and tile.

Short Tandem Repeat DNA Profiling Using Perylene-Oligonucleotide Fluorescence Assay

“…To our knowledge, this is the first report of an amplification-free STR ID profiling using human DNA. Given the acknowledged difficulties with enzyme-based STR detection, and their appeal as human ID and cancer research tools, − this work opens up new opportunity for a rapid and reliable STR profiling.…”

Recent Progress in Visualization and Analysis of Fingerprint Level 3 Features

“…[66][67][68][69][70] As a result, the immunolabeling application scenario for various substrates was expanded and subsequently proved to be fitted in DNA analysis. [71] Since the amount of dermcidin secreted is found to be variable and sometimes tiny, multi-target immunolabeling approaches that can simultaneously react with several peptides have exhibited great potential for high-quality pore visualization recently. [72,73] Compared with antigen-antibody interactions, the aptamer recognition methods open a facile pathway for the detection of level 3 details on account of their exceptionally high specificity and affinity to fingerprint residues.…”

“…To enhance the immunodetection signal, visible dyes, organic fluorophores and nanoparticles were later investigated to be tagged to the secondary antibody [66–70] . As a result, the immunolabeling application scenario for various substrates was expanded and subsequently proved to be fitted in DNA analysis [71] . Since the amount of dermcidin secreted is found to be variable and sometimes tiny, multi‐target immunolabeling approaches that can simultaneously react with several peptides have exhibited great potential for high‐quality pore visualization recently [72,73]…”