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Dive into the research topics where Santhosh Chidangil is active.

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Featured researches published by Santhosh Chidangil.


PLOS ONE | 2010

Raman Tweezers Spectroscopy of Live, Single Red and White Blood Cells

Aseefhali Bankapur; Elsa Zachariah; Santhosh Chidangil; Manna Valiathan; D. Mathur

An optical trap has been combined with a Raman spectrometer to make high-resolution measurements of Raman spectra of optically-immobilized, single, live red (RBC) and white blood cells (WBC) under physiological conditions. Tightly-focused, near infrared wavelength light (1064 nm) is utilized for trapping of single cells and 785 nm light is used for Raman excitation at low levels of incident power (few mW). Raman spectra of RBC recorded using this high-sensitivity, dual-wavelength apparatus has enabled identification of several additional lines; the hitherto-unreported lines originate purely from hemoglobin molecules. Raman spectra of single granulocytes and lymphocytes are interpreted on the basis of standard protein and nucleic acid vibrational spectroscopy data. The richness of the measured spectrum illustrates that Raman studies of live cells in suspension are more informative than conventional micro-Raman studies where the cells are chemically bound to a glass cover slip.


PLOS ONE | 2014

A Micro-Raman Study of Live, Single Red Blood Cells (RBCs) Treated with AgNO3 Nanoparticles

Aseefhali Bankapur; Surekha Barkur; Santhosh Chidangil; D. Mathur

Silver nanoparticles (Ag NPs) are known to exhibit broad antimicrobial activity. However, such activity continues to raise concerns in the context of the interaction of such NPs with biomolecules. In a physiological environment NPs interact with individual biological cells either by penetrating through the cell membrane or by adhering to the membrane. We have explored the interaction of Ag NPs with single optically-trapped, live erythrocytes (red blood cells, RBCs) using Raman Tweezers spectroscopy. Our experiments reveal that Ag NPs induce modifications within an RBC that appear to be irreversible. In particular we are able to identify that the heme conformation in an RBC transforms from the usual R-state (oxy-state) to the T-state (deoxy-state). We rationalize our observations by proposing a model for the nanoparticle cytotoxicity pathway when the NP size is larger than the membrane pore size. We propose that the interaction of Ag NPs with the cell surface induces damage brought about by alteration of intracellular pH caused by the blockage of the cell membrane transport.


Journal of Biomedical Optics | 2010

Evaluation of high-performance liquid chromatography laser-induced fluorescence for serum protein profiling for early diagnosis of oral cancer

Ajeetkumar Patil; Vijendra Prabhu; K.S. Choudhari; V. K. Unnikrishnan; Sajan. D. George; Ravikiran Ongole; Keerthilatha M. Pai; Jayarama Shetty; Sujatha Bhat; V. B. Kartha; Santhosh Chidangil

The present work deals with the evaluation of a high-performance liquid chromatography laser-induced fluorescence (HPLC-LIF) technique developed in our laboratory for early detection of oral cancer from protein profiles of body fluids. The results show that protein profiles of serum samples from a given class of samples, say, normal, premalignant, or malignant, are statistically very close to each other, while profiles of members of any class are significantly different from other classes. The performance of the technique is evaluated by the use of sensitivity and specificity pairs, receiver operating characteristic (ROC) analysis, and Youdens Index. The technique uses protein profile differences in serum samples, registered by the HPLC-LIF technique. The study is carried out using serum samples from volunteers diagnosed as normal or premalignant clinically, and as malignant by histopathology. The specificities and sensitivities of the HPLC-LIF method at an ideal threshold (M-distance = 2) for normal, malignant, and premalignant classes are 100, 69.5, and 61.5%, and 86.5, 87.5, and 87.5% respectively.


Journal of Biomedical Optics | 2015

Probing differentiation in cancer cell lines by single-cell micro-Raman spectroscopy

Surekha Barkur; Aseefhali Bankapur; Madhura Pradhan; Santhosh Chidangil; D. Mathur; Uma Ladiwala

Abstract. Single-cell micro-Raman spectroscopy has been applied to explore cell differentiation in single, live, and malignant cells from two tumor cell lines. The spectra of differentiated cells exhibit substantial enhancement primarily in the intensities of protein peaks with concomitant decrease in intensities of O─P─O asymmetric stretching peaks in DNA/RNA. Principal component analyses show that the spectral score of differentiated cells tends to asymptotically approach that of spectra obtained from normal neural stem cells/progenitors. This lends credence to the notion that the observed spectral changes are specific to differentiation, since upon differentiation, malignant cells become less malignant and tend toward benignity.


New Journal of Chemistry | 2017

Microwave solution route to ceramic ZnAl2O4 nanoparticles in 10 minutes: inversion and photophysical changes with thermal history

Samvit G. Menon; K.S. Choudhari; S. A. Shivashankar; Santhosh Chidangil; Suresh D. Kulkarni

Microwave-assisted synthesis of ZnAl2O4 nanoparticles in minutes using metalorganic precursors is reported. Phase-pure ZnAl2O4 with an average crystallite size of ∼5 nm is formed in the solution medium at 185 °C. Annealing in air at temperatures between 500 and 1200 °C increases the crystallite size to ∼32 nm. The as-prepared particles are largely shapeless, whereas polyhedral crystallites with well-defined grain boundaries can be seen in the HR-TEM image of the annealed samples. Diffuse reflectance spectroscopy provides insight into the structural development of the oxide spinel. Rapid synthesis leads to significant crystallographic inversion (∼33%), as observed by X-ray photoelectron spectroscopy. Photoluminescence spectroscopy shows that the different emission bands are due both to anti-site defects in the form of zinc interstitials caused by cationic inversion and to oxygen and zinc vacancies. Optical measurements suggest that inhomogeneity in cationic distribution, probably caused by the rapidity of synthesis, is prevalent even after annealing at temperatures up to 1200 °C, and plays a significant role in controlling the emission properties of the spinel. The microwave-assisted technique using metalorganic precursors is an easy path to the rapid synthesis of doped ZnAl2O4 phosphors.


Journal of Biomedical Optics | 2013

Salivary protein markers: a noninvasive protein profile-based method for the early diagnosis of oral premalignancy and malignancy

Ajeetkumar Patil; Khoobram S. Choudhari; Vayakkara Kolaprath Unnikrishnan; Nandita Shenoy; Ravikiran Ongole; Keerthilatha M. Pai; V. B. Kartha; Santhosh Chidangil

Abstract. An ultra-sensitive hyphenated technique, high-performance liquid chromatography-laser-induced fluorescence detection protein profiling of saliva, is evaluated for early detection and diagnosis of oral premalignancy and malignancy. Calibration sets of protein profiles of unstimulated whole saliva are collected from clinically/pathologically normal, premalignant, and malignant subjects and used as standards. Three parameters—scores of factors, sum of squared residuals, and Mahalanobis distance—derived from principal component analysis of protein profiles of the standard calibration sets, and blind samples are used for “match/no-match” diagnosis of the blind samples. Analyses of the results show that the method is capable of differentiating normal, premalignant, and malignant conditions with the sensitivity and specificity of 79% and 78%, respectively. The technique provides a fast, highly objective (free from personal judgment and statistically defined), and noninvasive diagnostic method for screening and early detection of oral cancer.


Journal of Photochemistry and Photobiology B-biology | 2017

Effect of infrared light on live blood cells: Role of β-carotene

Surekha Barkur; Aseefhali Bankapur; Santhosh Chidangil; D. Mathur

We have utilized Raman tweezers to measure and assign micro-Raman spectra of optically trapped, live red blood cells (RBCs), white blood cells (WBCs) and platelets. Various types of WBCs- both granulocytes, lymphocytes, and their different types have been studied. The Raman bands are assigned to different biomolecules of blood cells. The Raman spectra thus obtained has been enabled detection of β-carotene in these blood cells, the spectral features of which act as a signature that facilitates experimental probing of the effect of 785nm laser light on different blood cells as a function of incident laser power in the mW range. The spectral changes that we obtain upon laser irradiation indicate that, both haemoglobin as well as the cell membrane sustains damage. In case of lymphocytes and platelets the peaks corresponding to β-carotene showed drastic changes. Thorough analysis of the spectral changes indicates possibility of free radical induced damage of β-carotene in lymphocytes and platelets. Among different blood cells, RBCs have a power threshold of only 10mW. The power threshold for other types of blood cells is somewhat higher, but always below about 30mW. These values are likely to serve as useful guides for Raman tweezers based experiments on live cells.


Laser and Particle Beams | 2015

Micro-patterning of Indium thin film for generation of micron and submicron particles using femtosecond laser-induced forward transfer

Kamlesh Alti; Sudhanshu Dwivedi; Santhosh Chidangil; D. Mathur; Alika Khare

This paper reports on micro-pattering of Indium thin film (donor substrate) using a higher deposition dose than previously reported. The threshold deposition dose required for micro-patterning was measured. Ejected material from the micro-patterned thin film was deposited onto an accepter substrate kept in close proximity; it clearly shows deposition of micron and submicron particles of Indium. Moreover, a clean line like structure was deposited onto the accepter substrate when the accepter substrate was moved with the same velocity as that of the donor substrate.


Journal of Proteomics | 2015

Ultra-sensitive high performance liquid chromatography–laser-induced fluorescence based proteomics for clinical applications☆

Ajeetkumar Patil; Sujatha Bhat; Keerthilatha M. Pai; Lavanya Rai; V. B. Kartha; Santhosh Chidangil

UNLABELLED An ultra-sensitive high performance liquid chromatography-laser induced fluorescence (HPLC-LIF) based technique has been developed by our group at Manipal, for screening, early detection, and staging for various cancers, using protein profiling of clinical samples like, body fluids, cellular specimens, and biopsy-tissue. More than 300 protein profiles of different clinical samples (serum, saliva, cellular samples and tissue homogenates) from volunteers (normal, and different pre-malignant/malignant conditions) were recorded using this set-up. The protein profiles were analyzed using principal component analysis (PCA) to achieve objective detection and classification of malignant, premalignant and healthy conditions with high sensitivity and specificity. The HPLC-LIF protein profiling combined with PCA, as a routine method for screening, diagnosis, and staging of cervical cancer and oral cancer, is discussed in this paper. BIOLOGICAL SIGNIFICANCE In recent years, proteomics techniques have advanced tremendously in life sciences and medical sciences for the detection and identification of proteins in body fluids, tissue homogenates and cellular samples to understand biochemical mechanisms leading to different diseases. Some of the methods include techniques like high performance liquid chromatography, 2D-gel electrophoresis, MALDI-TOF-MS, SELDI-TOF-MS, CE-MS and LC-MS techniques. We have developed an ultra-sensitive high performance liquid chromatography-laser induced fluorescence (HPLC-LIF) based technique, for screening, early detection, and staging for various cancers, using protein profiling of clinical samples like, body fluids, cellular specimens, and biopsy-tissue. More than 300 protein profiles of different clinical samples (serum, saliva, cellular samples and tissue homogenates) from healthy and volunteers with different malignant conditions were recorded by using this set-up. The protein profile data were analyzed using principal component analysis (PCA) for objective classification and detection of malignant, premalignant and healthy conditions. The method is extremely sensitive to detect proteins with limit of detection of the order of femto-moles. The HPLC-LIF combined with PCA as a potential proteomic method for the diagnosis of oral cancer and cervical cancer has been discussed in this paper. This article is part of a Special Issue entitled: Proteomics in India.


Laser and Particle Beams | 2014

Femtosecond laser induced forward transfer of indium thin films

Thomas John; Rodney Bernard; John Thomas; Kamlesh Alti; Santhosh Chidangil

We report utilization of the laser induced forward transfer technique to re-deposit indium thin films onto the accepter substrate using nJ laser pulses from a femtosecond laser oscillator. Keeping the accepter substrate stationary enables dots of Indium to be deposited; in contrast, linear motion of the accepter substrate facilitates deposition of lines of Indium. The effect of laser pulse energy on the deposition process is studied. The effect of translation speed of donor substrate on the laser induced forward transfer pattern is also probed and an upper limit of translation speed is established beyond which smearing is observed to occur.

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D. Mathur

Tata Institute of Fundamental Research

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