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Dr Zarin A S


Non-invasive detection of microbial growth using tunable diode laser spectroscopy and its application to assess bacterial traits

Metabolic activity in all living organisms leads to concomitant emission of certain gases. Accurately measuring these gases can help us understand the underlying physiological processes. Such measurements have importance in fundamental bio-science studies, pharmaceutical drug development, bioreactor monitoring, planetary science studies and clinical microbiology. However, these measurements need to be made non-invasively and non-destructively so as not to contaminate the growth culture and to allow the growth process to continue undisturbed. We use calibration-free tunable diode laser absorption spectroscopy (TDLS) to make accurate, real time, non-invasive measurement of cumulative metabolic carbon dioxide emitted by bacterial cultures into the headspace of the culture vessel over several hours of its life cycle. The cumulative carbon dioxide measured has a sigmoidal curve which is the characteristic growth pattern of bacterial growth in a nutrient limited medium. Various growth parameters are extracted from this curve. My focus at present is to improve the detection sensitivity of the system and thus use TDLS as a tool for drug susceptibility tests.

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Journal papers

  1. Zarin A S, A L Chakraborty, "Time-resolved studies of bioluminescence from Photobacterium leiognathi and rapid antimicrobial susceptibility testing on E coli using tunable diode laser spectroscopy", IEEE Sensors Journal, May 2020,

  2. Zarin A S, A L Chakraborty and A Upadhyay, “Absolute and non-invasive measurements of CO2 emission from batch culture of E coli using calibration-free 2f wavelength modulation spectroscopy applied to a 2004 nm VCSEL”, Optics Letters, Vol. 42 No. 11, 2138-2141 (2017)

Conference papers

  1. Zarin A S, A L Chakraborty, S Khatua, "Non-invasive and simultaneous high time-resolution monitoring of CO2 emission and bio-luminescence in a batch culture of Photobacterium leiognathi", International Conference on Fiber Optics and Photonics (Photonics 2018), 12-15 Dec 2018, New Delhi (oral presentation)

  2. Zarin AS and A L Chakraborty, "Rapid and non-invasive anti-microbial susceptibility testing using tunable diode laser spectroscopy", International Conference on Cell Biology (ICCB 2018), 27-31 Jan 2018, Hyderabad, India

  3. Zarin A S, A L Chakraborty, A Upadhyay, "Detecting metabolic carbon dioxide using a tunable laser for non-invasive monitoring of growth of bacterial pathogens", oral presentation (1617/CL-4.6), CLEO Europe- EQEC 2017, 25-29 June 2017, Munich, Germany, doi: 10.1109/CLEOE-EQEC.2017.8087202

  4. Zarin AS and A L Chakraborty, “Absolute concentration measurements of bacterial CO2 emission using a 2004 nm vertical cavity surface emitting tunable diode laser”, 2015 IEEE Workshop on Recent Advances in Photonics (WRAP-2015), 13-16 Dec 2015, IISc Bangalore

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