A 74-year-old man presented with a four week history of behavioural disturbances, upper and lower extremity numbness and impaired balance. He had been treated with metronidazole for six months for osteomyelitis of the right hallux. Examination revealed encephalopathy, and glove-and-stocking sensory loss to pinprick with reduced vibration threshold at the toe. The gait was wide based and ataxic. Nerve conduction studies showed a large fibre sensory-motor axonal polyneuropathy. Magnetic resonance imaging (MRI) revealed a solitary restricted diffusion lesion in the splenium of the corpus callosum (Figure A, B) with subtle prolongation of T2 (Figure C). The radiographic differential diagnosis included hypoglycaemia, viral encephalitis, antiepileptic drug toxicity/withdrawal and metronidazole toxicity. The combination of the imaging finding with the history of prolonged metronidazole use suggested metronidazole induced encephalopathy.

We report the development of oxygen sensors using polymer photonic bandgap structure and CMOS chips. These integrated sensors provide a new platform for the development of low cost, low (battery) powered, light weight, robust, fast and small sensors. We demonstrate an approach to encapsulation of chemical and biological recognition elements within the porous structures. This sensing platform is built on our recently demonstrated nanofabrication technique using holographic interferometry of a photo-activated mixture that includes a volatile solvent as well as monomers, photoinitiators, and co-initiators. Resulting structure is nanoporous polymer 1D photonic bandgap structures that has reflection grating property and can be directly integrated into optical sensor systems that we have previously developed. For optical sensor system, CMOS (Complementary Metal Oxide Semiconductor) detectors that include phototransistors, trans impedance amplifier, and other signal processing units are used. Combining CMOS chip and nano-porous polymer reflection grating, we demonstrate an oxygen sensor as a prototype by encapsulating the fluorophore (tris(4,7-diphenyl-1,10-phenathroline)ruthenium(II) using fluorescence intensity.