Photo-dissolvable Swabs for Improved Recovery of Forensic Samples

• NCJ Number: 253069
• Author(s): Arunkumar Natarajan
• Date Published: July 2018
• Length: 16 pages
• Grant Number(s): 2015-DN-BX-K042
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical); Report (Summary); Report (Study/Research); Report (Grant Sponsored); Program/Project Description

Annotation

This is the Special Report Summary Overview of the findings and methodology of a research project whose goal was to develop novel photo-dissolvable swab materials that function as regular swabs during the collection of aqueous samples that can be completely degraded after exposure to DNA-friendly longwave UV lights, thereby enabling both high collection efficiency and maximum release for low abundance DNA samples.

Abstract

The research team successfully down-selected two photo-degradable material compositions; and it formulated electro-spun fibers with improved wettability, bio-specimen pick-up, and sample release into the PCR workflow upon photo-degradation. This was done using a polymer-blending approach and form factor improvement. In the first year, the project focused on developing photo-degradable materials and testing the photo-degradation kinetics, implementing the materials in PCR workflow to study inhibition of PCR. The materials were down-selected based on the performance. In the first year, the project also demonstrated that the photo-dissolvable swabs (at wave length of 365 nm) did not inhibit PCR reactions. The DNA was not affected during photo-degradation of PHEMA-NBS (100 percent, 50 percent, and 25 percent functionalized polymers), nor were the byproducts formed inhibitory to PCR reaction and subsequent analysis. The degradation wave length was selected as a compromise between reduced sensitivity to sunlight and potential DNA damage during the irradiation process. In the project's second year, it worked on scaling up the down-selected material and worked on developing electro-spun compositions, developing protocols, and enabling formulation of photo-degradable fibers that were rolled onto Q-tip or spun onto aluminum foils to enable mat format for downstream PCR analysis. Protocols were developed for sample placement and pick-up into the mats/swabs. It also developed a prototype UV-breadboard light for faster degradation of the photo-dissolvable polymer, and the light fixture was used to develop the PCR workflow. 16 figures and 2 tables