Color changing photonic crystals detect blast exposure

Abstract

Blast-induced traumatic brain injury (bTBI) is the "signature wound" of the current wars in Iraq and Afghanistan. However, with no objective information of relative blast exposure, warfighters with bTBI may not receive appropriate medical care and are at risk of being returned to the battlefield. Accordingly, we have created a colorimetric blast injury dosimeter (BID) that exploits material failure of photonic crystals to detect blast exposure. Appearing like a colored sticker, the BID is fabricated in photosensitive polymers via multi-beam interference lithography. Although very stable in the presence of heat, cold or physical impact, sculpted micro-and nano-structures of the BID are physically altered in a precise manner by blast exposure, resulting in color changes that correspond with blast intensity. This approach offers a lightweight, power-free sensor that can be readily interpreted by the naked eye. Importantly, with future refinement this technology may be deployed to identify soldiers exposed to blast at levels suggested to be supra-threshold for nonimpact blast-induced mild TBI.

25th Anniversary Article: Ordered Polymer Structures for the Engineering of Photons and Phonons

“…Blast and Shockwave Sensing : The structural colors of a glassy or semicrystalline PhC can be permanently altered by plastic deformation of a polymer/air structure due to shock waves, including blast. Cullen et al created a colorimetic blast injury dosimeter utilizing 3D polymeric PhCs fabricated by multi‐beam IL and investigated blast‐induced color change as shown in Figure a . A mixture of hydrogen and oxygen gases was exploded in a cylindrical shocktube and the blast was transferred along the tube to impact the sample.…”

“…The SEM images allow identification of changes in the structural features of the blast injury dosimeter after the shock. Reproduced with permission . Copyright 2010, Elsevier Inc. (b) Photograph of a transparent PhC shows colors at elevated temperature and its temperature‐dependent optical scattering spectra.…”

Photonic crystals: emerging biosensors and their promise for point-of-care applications

“…For example, 3-D PC structures were investigated under pressure and may conceptually be used for detecting the severity of blast exposure to evaluate traumatic brain injury of soldiers in the battlefield. 148,149 In this study, 3-D voids were fabricated in an SU-8 resist to create 3-D PC structures that exhibited a color in the visible spectrum. These structures were exposed to varying high pressures (410 to 1090 kPa) to measure blast strength (Fig.…”

Fabrication of Colloidal Laves Phases via Hard Tetramers and Hard Spheres: Bulk Phase Diagram and Sedimentation Behavior

“…These structures act for photons in the same way as semiconductors do for electrons, hence opening up a way to control light propagation. The application area of such materials is quite broad, ranging from optical fibers, displays and switches to (bio-)sensing and bio-medical engineering, and finally to energy storage and security [8][9][10][11][12][13][14][15][16][17][18][19] . Therefore, a significant amount of research in the colloid science community deals with the design and fabrication of such photonic crystals.…”