You know the drill from TV. Forensics experts scour a crime scene, using cotton swabs resembling Q-tips to collect forensic samples left by criminals on doorknobs, table surfaces and other areas.
But the issue you don’t hear about today is that the samples gathered must be substantial for the evidence to be admissible in court. That’s because current swabs, although they can pick up a sample well, won’t always release enough of it for forensic analysis. “Our tests show that samples are certainly lost using cotton, and that we should be delivering everything," says GE molecular biologist John Nelson, who is part of the team. "We could get down to individual cells.”
DNA forensics is a powerful tool for law enforcement in solving crimes, especially those seemingly unsolvable cases. After nearly four decades, it was DNA forensics that finally brought the infamous Golden State Killer to justice. Ironically, that happened on April 25 — National DNA Day. But all too often, not enough DNA can be recovered from forensic samples to provide valuable information, raising the question of how many more crimes could be solved with better sample collection.
The GE team is working to develop a new swab for trace-sample collection that could reduce the number of unsolved crimes. Through a $500,000 grant from the National Institute of Justice, they pooled their expertise in polymer materials, DNA analysis and biochemistry to find a solution. Early tests show that the method could be much more sensitive than existing methods. “Instead of using cotton for the swab, we have developed a special fiber that resembles cotton candy that is used to gather a sample," said Arunkumar Natarajan, a senior scientist and chemist at the GE labs. "But unlike cotton, it will later dissolve to release the entire sample when exposed to just the right wavelength of light. By swabbing and releasing the entire sample collected, trace amounts can be analyzed more effectively.”
Individually, the team members have worked on a variety of projects that span multiple industry sectors. Natarajan recently worked with GE’s Aviation and Additive businesses to develop a 3D binder jet technology for GE applications. Others are working in healthcare, exploring new methods for vaccine development, cutting-edge tools in bioelectronic medicine to treat chronic diseases such as diabetes, and methods to analyze tissue biopsies more completely. Natarajan said the trace sample idea was hatched during one of the many serendipitous encounters that happen in the halls of the GE labs many times a day. “I was having a conversation about forensics with John Nelson, who also is one of the foremost experts in DNA technology,” Natarajan said. “We put two and two together, pairing the material expertise with biology to create this new collection process.”
The next step was to contact a friend, Professor Abraham Joy at the University of Akron, an expert in polymer chemistry. Joy and Natarajan came up with a plan to develop a fiber that would be sensitive to light, and used the grant to produce it. “The law enforcement community has been looking for this type of breakthrough for years," Nelson said. "Now we finally have a material that will allow us to analyze trace samples more efficiently.”
Sireesha Kaanumalle, a chemist, and Wei Gao, a molecular biologist, round out the “CSI” team. “The materials used are like magic," Kaanumalle said. "In natural sunlight, the special polymer material we created will not degrade at all.” Gao added that “exposed to certain light wavelengths, the polymer will dissolve completely. And the process does not affect the DNA at all. It’s the wonders of chemistry at play,” he said.
The team has filed patents for the material and for the processing and manufacturing of the new swab. The next step is to begin testing the forensics technology with collaborators in the field. The goal is to ultimately solve this case and provide law enforcement with even better DNA-analysis tools to solve crimes.