Navegando por Autor "Barman, Ishan"

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Label-free route to rapid, nanoscale characterization of cellular structure and dynamics through opaque media.
(2013) Joshi, Bipin; Barman, Ishan; Dingari, Narahara Chari; Cardenas, Nelson; Soares, Jaqueline dos Santos; Dasari, Ramachandra Rao; Mohanty, Samarendra
We report a novel technique for label-free, rapid visualization of structure and dynamics of live cells with nanoscale sensitivity through traditionally opaque media. Specifically, by combining principles of near-infrared (NIR) spectroscopy and quantitative phase imaging, functional characterization of cellular structure and dynamics through silicon substrates is realized in our study. We demonstrate the efficacy of the new approach by full-field imaging of erythrocyte morphology in their native states with a nm path length sensitivity. Additionally, we observe dynamic variations of human embryonic kidney cells, through a silicon substrate, in response to hypotonic stimulation with ms temporal resolution that also provides unique insight into the underlying biophysical changes. The proposed technology is fundamentally suited for high-performance investigations of biological specimens and significantly expands the options for visualization in complex microfluidic devices fabricated on silicon.
Raman spectroscopic sensing of carbonate intercalation in breast microcalcifications at stereotactic biopsy.
(2015) Sathyavathi, R.; Saha, Anushree; Soares, Jaqueline dos Santos; Spegazzini, Nicolas; McGee, Sasha; Dasari, Ramachandra Rao; Fitzmaurice, Maryann; Barman, Ishan
Microcalcifications are an early mammographic sign of breast cancer and frequent target for stereotactic biopsy. Despite their indisputable value, microcalcifications, particularly of the type II variety that are comprised of calcium hydroxyapatite deposits, remain one of the least understood disease markers. Here we employed Raman spectroscopy to elucidate the relationship between pathogenicity of breast lesions in fresh biopsy cores and composition of type II microcalcifications. Using a chemometric model of chemical-morphological constituents, acquired Raman spectra were translated to characterize chemical makeup of the lesions. We find that increase in carbonate intercalation in the hydroxyapatite lattice can be reliably employed to differentiate benign from malignant lesions, with algorithms based only on carbonate and cytoplasmic protein content exhibiting excellent negative predictive value (93–98%). Our findings highlight the importance of calcium carbonate, an underrated constituent of microcalcifications, as a spectroscopic marker in breast pathology evaluation and pave the way for improved biopsy guidance.
Raman spectroscopy with a 1064-nm wavelength laser as a potential molecular tool for prostate cancer diagnosis : a pilot study.
(2018) Magalhães, Felipe Lima; Machado, Alexei Manso Corrêa; Paulino Junior, Eduardo; Sahoo, Sangram K.; Paula, Ana Maria de; Garcia, Aloísio Miguel; Barman, Ishan; Soares, Jaqueline dos Santos; Lewer, Marcelo Henrique Mamede
Raman spectroscopy is widely used to investigate the structure and property of the molecules from their vibrational transitions and may allow for the diagnosis of cancer in a fast, objective, and nondestructive manner. This experimental study aims to propose the use of the 1064-nm wavelength laser in a Raman spectroscopy and to evaluate its discrimination capability in prostate cancer diagnosis. Seventy-four spectra from patients who underwent radical prostatectomy were evaluated. The acquired signals were filtered, normalized, and corrected for possible oscillations in the laser intensity and fluorescence effects. Wilcoxon tests revealed significant differences between the benign and malign samples associated with the deformation vibration characteristic of nucleic acids, proteins, and lipids. A classifier based on support vector machines was able to predict the Gleason scores of the samples with 95% of accuracy, opening a perspective for the use of the 1064-nm excitatory wavelength in prostatic cancer diagnosis.