Spray-On Films Developed By Chemists Reveal Traces Of Explosives

New spray-on films developed by UC San Diego chemists will be the basis of portable devices that can quickly reveal trace amounts of nitrogen-based explosives.

Contaminated fingerprints leave dark shadows on the films, which glow blue under ultraviolet light. One of the films can distinguish between different classes of explosive chemicals, a property that could provide evidence to help solve a crime, or prevent one.

A recent episode of CSI: Miami featured the technology, which linked fingerprints left on a video camera to a bomb used in a bank heist, revealing the motive for the robbery. In real life, the security systems company RedXDefense has developed a portable kit based on the technology that security officers could use with minimal training.

Detection relies on fluorescent polymers developed at UCSD by chemistry and biochemistry professor William Trogler and graduate student Jason Sanchez.

“It’s a very intuitive detection method that doesn’t require a scientist to run,” Trogler said.

Sanchez and Trogler describe the synthesis and properties of their polymers in a forthcoming issue of the Journal of Materials Chemistry.

The polymers emit blue light when excited by ultraviolet radiation. Nitrogen-based explosive chemicals such as TNT quench that glow by soaking up electrons.

Because the polymers fluoresce brightly, no special instruments are needed to read the results. Only a very thin film sprayed on a suspect surface is needed to reveal the presence of a dangerous chemical. A single layer of the polymer, about one thousandth of a gram, is enough to detect minute amounts of some explosives, as little as a few trillionths of a gram (picograms) on a surface a half-foot in diameter. Handling explosives can leave 1,000 times that quantity or more stuck to fingers or vehicles.

The films also adhere directly to potentially contaminated surfaces, making them more sensitive than previous methods, which rely on capturing molecules that escape into the air.

Detection can be fast, revealing incriminating fingerprints as soon as the solvents dry, within 30 seconds. Exposure to ultraviolet light for a minute or two alters one of the films so that traces a nitrate esters, a class chemicals that includes the highly explosive PTEN, begin to glow green. Traces of other classes of explosives, such as nitroaromatics like TNT, stay dark.

Trogler’s group is currently developing similar systems to detect explosives based on peroxides.

The Air Force Office of Scientific Research and RedXDefense funded the research. Sanchez was supported by the National Science Foundation.

Trogler serves on the strategic advisory board of RedXDefense, which has licensed the technology from UCSD.

Featured

  • Data Driven, Proactive Response

    As cities face rising demands for smarter policing and faster emergency response, Real Time Crime Centers (RTCCs) are emerging as essential hubs for data-driven public safety. In this interview, two experts with deep field experience — Ross Bourgeois of New Orleans and Dean Cunningham of Axis Communications — draw on decades of operational, leadership and technology expertise to share how RTCCs are transforming public safety through innovation, interagency collaboration and a relentless focus on community impact. Read Now

  • Integration Imagination: The Future of Connected Operations

    Security teams that collaborate cross-functionally and apply imagination and creativity to envision and design their ideal integrated ecosystem will have the biggest upside to corporate security and operational benefits. Read Now

  • Smarter Access Starts with Flexibility

    Today’s workplaces are undergoing a rapid evolution, driven by hybrid work models, emerging smart technologies, and flexible work schedules. To keep pace with growing workplace demands, buildings are becoming more dynamic – capable of adapting to how people move, work, and interact in real-time. Read Now

  • Trends Keeping an Eye on Business Decisions

    Today, AI continues to transform the way data is used to make important business decisions. AI and the cloud together are redefining how video surveillance systems are being used to simulate human intelligence by combining data analysis, prediction, and process automation with minimal human intervention. Many organizations are upgrading their surveillance systems to reap the benefits of technologies like AI and cloud applications. Read Now

  • Right-Wing Activist Charlie Kirk Dies After Utah Valley University Shooting

    Charlie Kirk, a popular conservative activist and founder of Turning Point USA, died Wednesday after being shot during an on-campus event at Utah Valley University in Orem, Utah Read Now

New Products

  • Connect ONE’s powerful cloud-hosted management platform provides the means to tailor lockdowns and emergency mass notifications throughout a facility – while simultaneously alerting occupants to hazards or next steps, like evacuation.

    Connect ONE®

    Connect ONE’s powerful cloud-hosted management platform provides the means to tailor lockdowns and emergency mass notifications throughout a facility – while simultaneously alerting occupants to hazards or next steps, like evacuation.

  • EasyGate SPT and SPD

    EasyGate SPT SPD

    Security solutions do not have to be ordinary, let alone unattractive. Having renewed their best-selling speed gates, Cominfo has once again demonstrated their Art of Security philosophy in practice — and confirmed their position as an industry-leading manufacturers of premium speed gates and turnstiles.

  • AC Nio

    AC Nio

    Aiphone, a leading international manufacturer of intercom, access control, and emergency communication products, has introduced the AC Nio, its access control management software, an important addition to its new line of access control solutions.