Luna.’s Dissolvable Swabs can Revolutionize Crime Scene Investigations
法医拭子在刑事调查中没有按需执行
Forensic swabs are routinely used by crime scene investigators and forensic scientists for the collection of a wide range of evidence types for analysis (Figure 1). Collecting biological samples for subsequent DNA analysis is one of the primary uses for forensic swabs. These swabs are used to adsorb blood, saliva, sexual assault evidence, and what is called “触摸DNA”: skin cells shed during the process of handling an object.
Commercially available forensic swabs typically have great performance at adsorbing biological material from various surfaces, though they do not perform as well at releasing material from the swab for subsequent DNA analysis. The consequences of this are clear in cases when only a few cells are available for analysis: if a small number of cells are adsorbed onto the swab, but only one or two are released by the forensic scientist back in the laboratory, there may not be sufficient DNA material to perform an analysis. This is of critical importance in cases of sexual assault when the victim has taken a shower prior to reporting the incident and most evidence has been washed away, and in cases involving touch DNA where only a few cells are available for analysis.
Luna的高性能法医拭子彻底改变了该领域
为了解决这一限制，Luna Innovations正在开发一种新型的法医拭子。Luna的拭子技术通过完全重新想象使用的材料而开始。虽然现有的法医拭子通常使用直径约20微米的棉花或人造丝纤维，但Luna已经更小：0.2微米（图2）。这种尺寸的两个阶数减小纤维直径意味着对于相同的材料重量，Luna的拭子具有100倍的表面积。这项创新使Luna的拭子更大的表面机会拿起生物标本。
Additionally, Luna has moved to an innovative new fiber material: cellulose acetate. Cellulose acetate is an inexpensive material derived from the plant polymer cellulose, but with some acetyl substitutions. This polymer is amenable to being spun into 0.2 micrometer fibers, and has unique solvent interactions relevant for forensic DNA analysis. Cellulose acetate is insoluble in water, detergents, ethanol and most other common liquids and solutions you may find around a house, a business, or the outdoors. However, cellulose acetate completely dissolves in a旋流解, which are commonly found as part of DNA extraction protocols (Figure 3). This feature allows for 100% of the biological material on a forensic swab to be released for analysis.
Luna.has already demonstrated that our forensic swabs are superior to commercial forensic swabs in conditions where Luna’s swabs are not even dissolved (Figure 4). In this investigation, swabs were used to adsorb biological material off of surfaces, then all forensic swabs subjected to a standard DNA extraction protocol that does not support swab dissolution. Luna’s excellent swab performance in this study is likely due to the nanoscale cellulose fibers of the material both adsorbing a large amount of biological material, and also due to the size of the fibers preventing biological material entanglement during the extraction protocol.
The future of Luna’s swab is bright
Luna正在展示其拭子技术69.th美国法医科学院年会在新奥尔良，洛杉矶。加入我们在刑事局会议期间，于第2/16/17周四下午5:15下午5:15，了解这项令人兴奋的技术。
This material is based upon work supported by the U.S. Army Research Office under Contract No. W911NF-16-C-0113. The content of the information does not necessarily reflect the position or the policy of the Government, and no official endorsement should be inferred.