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Raman imaging is one of the very informative methods for the characterization of chemically and structurally heterogeneous materials without employing specific molecular labels. Multifocus Raman imaging is one of the fast-imaging alternatives to the conventional single point mapping technique. Since multiple focal points probe the sample simultaneously, this imaging methodology is faster compared to single point mapping. We have further demonstrated the efficiency of this methodology by investigating the morphological features of a porous PMMA film. A Raman image of a 50 × 50 μm(2) area was obtained in less than 4 minutes (with a 10 × 10 multifocus configuration). Importantly, a 100 × 100 μm(2) area could now be analyzed in minutes while a similar Raman image by single point mapping would take hours to days. Optical sectioning using multifocus Raman imaging reveals unique hierarchical features of the porous polymer thin film. Larger pores are limited to the surface and the inner bulk exhibits characteristic small-pores and an interconnected highly porous morphology. The fast multifocal Raman imaging would be advantageous to the diverse field of scientific disciplines where the speed of image acquisition remains a challenge despite the unparalleled specificity and sensitivity of Raman spectroscopy.

We have developed an automatic and objective method for detecting human oral squamous cell carcinoma (OSCC) tissues with Raman microspectroscopy. We measure 196 independent Raman spectra from 196 different points of one oral tissue sample and globally analyze these spectra using a Multivariate Curve Resolution (MCR) analysis. Discrimination of OSCC tissues is automatically and objectively made by spectral matching comparison of the MCR decomposed Raman spectra and the standard Raman spectrum of keratin, a well-established molecular marker of OSCC. We use a total of 24 tissue samples, 10 OSCC and 10 normal tissues from the same 10 patients, 3 OSCC and 1 normal tissues from different patients. Following the newly developed protocol presented here, we have been able to detect OSCC tissues with 77 to 92% sensitivity (depending on how to define positivity) and 100% specificity. The present approach lends itself to a reliable clinical diagnosis of OSCC substantiated by the “molecular fingerprint” of keratin.

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An extremely long-lived localised singlet diradical with π-single bonding character is found in a macrocyclic structure that retards the radical–radical coupling reaction by the “stretch and solvent-dynamic effects”.