Raghavendra Sai V V


Ph.D., Indian Institute of Technology, Bombay, India Thesis: Design and Development of Label-Free Optical Biosensors; Two novel, cost effective and field deployable sensing schemes for detection of bacteria and proteins have been demonstrated (July 2003 - December 2008).

B.E., Andhra University, Visakhapatnam, India (Electronics & Instrumentation) (1998-2002).



 Research Interests

  • Clinical diagnostics and therapeutics using nanomaterials and nano-devices.
  • Sensors for environmental monitoring, detection of toxins & explosives.
  • Fiber optic sensors, nanotechnology, noble metal nanoparticles.
  • Localized surface plasmon resonance (LSPR) and Surface enhanced Raman Scattering (SERS).

 Office Location

   Dr. V V Raghavendra Sai ,
   Biosensors Laboratory ,
    Department of Applied Mechanics & Biomedical Engineering, (Aerospace building)
   Indian Institute of Technology, Chennai - 600036.
   Office: + 91 44 2257 4076 , 91 44 2257 5012
   Fax : +91 44 2257 4052
   Email: vvrsai@iitm.ac.in


Ph.D. (July 2003- Dec 2008)

Indian Institute of Technology, Bombay, India Thesis: Design and Development of Label-Free Optical Biosensors Two novel, cost effective and field deployable sensing schemes for detection of bacteria and proteins have been demonstrated.

Bachelor of Engg. (1998-2002)

Andhra University, Visakhapatnam, India (Electronics & Instrumentation)

Professional Work Experience

August 2017 – Present

Associate Professor, Department of Applied Mechanics, IIT Madras

August 2011 – Present

Associate Professor, Department of Applied Mechanics, IIT Madras

Mar 2009 – Feb 2011

Post Doctoral Fellow, University of Idaho, Moscow, ID Worked on development of surface enhanced Raman scattering (SERS) based DNA biosensor, receptor mediated detection of explosives and applications of nanomaterials for development of drug delivery systems for anti-sense and anti-gene oligonucleotide based therapeutics.

Jan 2009 - Continued a part of Ph.D work

Research Associate, IIT Bombay, Mumbai, India The development of sensing modalities for field deployable biosensors. Improvements to the existing sensor probes were proposed. Some of the proposed sensor designs have been demonstrated successfully.

August 2002 – June 2003

Lecturer, GVP College of Engg, Visakhapatnam, India Responsibilities consisted of teaching courses and running lab sessions.

   Research Experience

Surface enhanced Raman scattering (SERS) based sensors

  • Design of highly sensitive SERS substrates using noble metal nanoparticles coated silica nanosprings that have very high surface-to-volume ratio.
  • Investigation of different sizes of gold and silver nanoparticles to achieve highest possible Raman enhancement. Enhancement factor approaching a theoretical maximum, up to 1010, was obtained.

 Drug delivery using gold nanostructures

  • Investigation of Gold nanoparticles and nanorods as carriers for a variety of chemically modified oligonucleotides in the cellular medium
  • Synthesis and characterization of nanoconjugates as a part of research on drug delivery using nanomaterials

 Explosive detection

  • Functionalization of gold nanoparticles coated nanospring with specific receptors for detection of explosive molecules in gas phase using conduction based measurements

 Optical waveguide (fiber optic) based chemical and biosensors

  • Development of evanescent wave absorbance based fiber optic biosensors exploiting absorbance properties of proteins and bacteria at 280 nm wavelength
  • Demonstration of suitability of U-bend probes for very large target analytes such as E.coli and other bacteria (>100 nm size) using the above-mentioned technique
  • Development of localized surface plasmon resonance (LSPR) based biosensor using gold nanoparticle bound fiber optic probes with ability to detect less than 35 microRIU (refractive index units)

 Surface modification techniques to introduce organic functional groups

  • Aminosilanization on SiO2, silica core optical fiber, SU-8 and use of crosslinkers
  • Self-assembled monolayers (SAMs) of thiols on gold or AuNP coated substrates
  • Surface functionalization of Polyaniline and SU-8 for biosensor applications
  • Improvement in hydrophilicity of gold and PDMS microchannels for microfluidics

  Immobilization of gold nanoparticles and proteins

  • Thin films of gold nanoparticles on aminosilanized silica nanostructures, glass and fiber substrates Antibody immobilization on glass and other similar surfaces by means of silanization, CM-Dextran method and through biotin-avidin complex

Characterization tools

  • Hands-on experience in fluorescence and optical microscopy, scanning electron microscopy (SEM) and dynamic light scattering (DLS)
  • Surface characterization tools for organic functional group analysis such as X-ray photoelectron spectroscopy (XPS), FTIR spectroscopy in grazing angle and ATR modes and contact angle meter
  • Spectroscopic techniques such as UV-Vis and fluorescence spectroscopy and quartz crystal microbalance (QCM) mass sensitive technique Knowledge in other nanocharacterization tools such as TEM and AFM


  • U-bent plastic optical fiber probes as refractive index based fat sensor for milk quality monitoring, A Gowri, AS Rajamani, B Ramakrishna, VVR Sai, Optical Fiber Technology (2019) pp 15-20, Available online, doi: 10.1016/j.yofte.2018.11.019
  • Nanomaterials based optical and electrochemical sensing of histamine: Progress and perspectives, S Yadav, SS Nair, VVR Sai, J Satija, Food Research International (2019) pp 99-109, Available online, doi: 10.1016/j.foodres.2019.01.045
  • Plasmonic biosensors for bacterial endotoxin detection on biomimetic C-18 supported fiber optic probes, H Manoharan, P Kalita, S Gupta, VVR Sai, Biosensors and Bioelectronics (2019) pp 79-86, Available online, doi: 10.1016/j.bios.2018.12.045
  • Graphene oxide coated U-bent plastic optical fiber based chemical sensor for organic solvents, Divagar M, Gowri A, Sangeeth John, V. V. R. Sai, Sensors and Actuators B Chemical (2018) pp 1006-1012, Available online, doi: 10.1016/j.snb.2018.02.059
  • Development of plasmonic U-bent plastic optical fiber probes for surface enhanced Raman scattering based biosensing, Christina Christopher, A. Subrahmanyam, V. V. R. Sai, Journal of Raman Spectroscopy (2018) pp 1607-1616, Available online, doi: 10.1002/jrs.5448
  • Gold Sputtered U-Bent Plastic Optical Fiber Probes as SPR- and LSPR-Based Compact Plasmonic Sensors, Christina Christopher, A. Subrahmanyam, V. V. R. Sai, Plasmonics (2017) pp 1-10, Available online, doi: 10.1007/s11468-017-0535-z
  • PMMA Surface Functionalization using Atmospheric Pressure Plasma for Development of Plasmonically Active Polymer Optical Fiber Probes, Priyanka Vasanthakumari, Zohreh Khosravi, V.V.R. Sai, Claus-Peter Klages Plasma Chemistry and Plasma Processing, 1-17 , doi: 10.1007/s11090-016-9717-2
  • Development of LSPR based U-bent plastic optical fiber sensors. A Gowri, VVR Sai Sensors and Actuators B 230 (2016) 536–543, doi: 10.1016/j.snb.2016.02.074
  • Evanescent Wave Absorbance based U-Bent Fiber Probe for Immunobiosensor with Gold Nanoparticle Labels. Bandaru Ramakrishna, VVR Sai Sensors and Actuators B 226 (2016) 184–190 doi: 10.1016/j.snb.2015.11.107
  • Self-Assembled Monolayers of Thiols Adsorbed on Au/ZnO-Functionalized Silica Nanosprings: Photoelectron Spectroscopy-Analysis and Detection of Vaporized Explosives. BA Fouetio Kengne, S Karmakar, M Kaura, VVR Sai, G Corti, IB Niraula, ACS applied materials & interfaces 6 (16), 13355-13366. doi: 10.1021/am504371k
  • Optimal design for U-bent fiber-optic LSPR sensor probes.J Satija, NS Punjabi, VVR Sai, S Mukherji. Plasmonics 9 (2), 251-260 doi: 10.1007/s11468-013-9618-7
  • Evanescent wave absorbance based fiber optic biosensor for label-free detection of E. coli at 280nm wavelength. R Bharadwaj, VVR Sai, K Thakare, A Dhawangale, T Kundu, S Titus, Biosensors and Bioelectronics 26 (7), 3367-3370doi:10.1016/j.bios.2010.12.014
  • Dendrimers in biosensors: Concept and applications. J Satija, VVR Sai, S Mukherji Journal of Materials Chemistry 21 (38), 14367-14386 doi: 10.1039/C1JM10527B
  • Silica nanosprings coated with noble metal nanoparticles: Highly active SERS substrates. VVR Sai, D Gangadean, I Niraula, JMF Jabal, G Corti, DN McIlroy The Journal of Physical Chemistry C 115 (2), 453-459 doi: 10.1021/jp109586f
  • Development of evanescent wave absorbance-based fibre-optic biosensor. T Kundu, VVR Sai, R Dutta, S Titas, P Kumar, S Mukherjee Pramana 75 (6), 1099-1113 doi: 10.1007/s12043-010-0193-6
  • Label-free fiber optic biosensor based on evanescent wave absorbance at 280nm. VVR Sai, T Kundu, C Deshmukh, S Titus, P Kumar, S Mukherji Sensors and Actuators B: Chemical 143 (2), 724-730 doi:10.1016/j.snb.2009.10.021
  • Emerging use of nanostructure films containing capped gold nanoparticles in biosensors. J Satija, R Bharadwaj, VVR Sai, S Mukherji Nanotechnology, science and applications 3, 171 doi: 10.2147/NSA.S8981
  • Simple surface modification techniques for immobilization of biomolecules on SU-8. A Deepu, VVR Sai, S Mukherji Journal of Materials Science: Materials in Medicine 20 (1), 25-28 doi: 10.1007/s10856-008-3471-9
  • Novel U-bent fiber optic probe for localized surface plasmon resonance based biosensor. VVR Sai, T Kundu, S Mukherji Biosensors and Bioelectronics 24 (9), 2804-2809 doi:10.1016/j.bios.2009.02.007
  • Immobilization of antibodies on polyaniline films and its application in a piezoelectric immunosensor VVR Sai, S Mahajan, AQ Contractor, S Mukherji Analytical chemistry 78 (24), 8368-8373 doi: 10.1021/ac060120a


  • Optical fiber probe. VVR Sai, S Mukherji, T Kundu. US Patent 8,476,007
  • An optical fiber sensor and method of fabricating the sensor. Gowri A and V V R Sai. Indian Patent Application No. 201641017866, filed 25th May, 2016.
  • Fiber optic Array Biosensor system with U-bent fiber sensor probes for multianalyte detection in clinical and pharmaceutical applications. Allwyn S, Bandaru Ramakrishna, Christina Christopher, V.V.R.Sai. Provisional Indian Patent Application No. 201641026626, filed 04th Aug, 2016


Doctoral Scholars

  • Hariharan Manoharan
  • Ankitha Theres George
  • Divagar Murugan

Post Doctoral Fellows

  • Dr. Vayunandana Kishore
  • Dr. Sruthi Prasood Usha

Senior Project Officer

  • V Lakhsmana Swamy Vonumu

Project Assistant

  • Medisetty Satish


  • Mahendrakar SaiCharan (Dual Degree 2008-2013)
  • Kavitha Pujari (Dual Degree 2008-2013)
  • Manojit R (Dual Degree 2009-2014)
  • Godam Aashresha (M.Tech 2014-2016)
  • Thrilok Venkat (Dual Degree 2011-2016)
  • Uma Maheshwari (M.Tech 2015-2017)
  • Priyanka V (M.S 2013-2016)
  • Dr. Ramakrishna Bandaru (Ph.D)
  • Dr. Gowri Annasamy (Ph.D)
  • Dr. Christina Grace Charlet (Ph.D)
  • Allwyn S Rajamani (M.S)


Project Title Agency Value (in Lakhs) Role Duration

Multiplexed label-free fiber optic biosensor array for waterborne pathogen detection (Multi-WAP)

IGSTC, India 160 PI with Prof. Subrahmanyam (co-PI) 2016-19

Scanning Kelvin Probe Equipment for Surface and Interface Analyses

DST, India 45.52 Co-PI with Prof. Subrahmanyam (PI) 2016-18

Development Of Microfluidics Based Healthcare Diagnostics

- 200 Co-PI in IITM Team Project 2015-17

Development of SERS based substrates for toxin detection

DRDE, Gwalior, India 163.55 Co-PI with Prof. Subrahmanyam (PI) 2013-15

Plasmonic Biosensors for Clinical Diagnosis

IIT Madras, India 15 PI 2011-14

Biological Applications of Nanotechnology (BANTech)

University of Idaho, Moscow, USA - PDF 2009-10

Functionalized Nanospring-mats for detection of Explosive Materials

Department of Defense, USA - Co-Investigator, 2009-11

Optoelectronic biosensors for waterborne pathogenic bacteria

Naval Material Research Lab, Ambernath - Graduate student 2004-09

Center for excellence in Nanoelectronics

Ministry of IT & communications, Govt. of India - Graduate student 2006-08

Polymeric waveguide based biosensors

Dept. of Biotechnology, Govt. of India - Graduate student 2006-08

Microcantilever based biosensor for cardiac markers (i-sens)

Dept. of Science & Technology, Govt. of India - Graduate student 2004-05

List of Courses Taught

  • Jan-May 2012 - AM1100 Engineering Mechanics (85 Students)
  • Jul-Nov 2012 - AM3010 Introduction to Biomechanics (37 students)
  • Jan-May 2013 - AM5140 Biomedical Instrumentation (19 students) & AM3020 Fundamentals of Medical Instrumentation (62 students)
  • Jul-Nov 2013 - AM3010 Introduction to Biomechanics (35 students)
  • Jan-May 2014 - AM5140 Biomedical Instrumentation (25 students) & AM3020 Fundamentals of Medical Instrumentation (36 students)
  • Jul-Nov 2014 - AM3010 Introduction to Biomechanics (20 students)
  • Jan-May 2015 - AM1100 Engineering Mechanics (85 students)
  • Jul-Sept 2015 - AM5520 Medical Electronics (17 students) & AM1100 Engineering Mechanics (34 students)
  • Jan-May 2016 - AM6514 Biomedical Sensors (4 students)
  • Jul-Nov 2016 - AM5520 Medical Electronics (10 students)
  • Jan-May 2017 - AM3020 Fundamentals of Medical Instrumentation (8 students)


Current Students

  • Gowri A (Ph.D., Jan 2013)
  • Christina Christopher (Ph.D., Jul 2013)
  • Ramakrishna B (Ph.D., Dec 2011)
  • Hariharan Manoharan (Ph.D., Jan 2014)  
  • Divagar Murugan (Ph.D., Jun 2017)  
  • Kuzhandai Shamlee J (Ph.D., Jun 2017)  
  • Swetha S Menon (Ph.D., Jun 2017)
  • Allwyn S Rajamani (Ph.D., Jan 2016)

Past Students

  • Gayathri Subramanian (Summer Intern 2015)
  • Aashresha(M.Tech., Jun 2015)
  • Thrilok N (M.Tech., Jun 2015) 
  • Ravikiran Reddy N (Dual Degree, Jun 2014)
  • Ali Javed (Dual Degree, Jun2014)
  • Priyanka V (M.S., Jul 2013)
  • Sanjuna S (Winter Intern, 2014)
  • Manojit Roy (M.Tech., 2014)  
  • Aswini S (Summer Interns, 2013)
  • Kavita Pujari (Dual Degree, 2013)
  • Saicharan Mahendrakar (Dual Degree , 2013)
  • Mathews John (Summer Intern, 2012)
  • Ramya Ramesh (Summer Intern, 2012)
  • Deep Pokharel, undergraduate, Univ. of Idaho  
  • Mason Fredrickson, undergraduate, Univ. of Idaho   
  • Reshma Bharadwaj, project staff, IIT Bombay  
  • Jitendra Satija, graduate, IIT Bombay  
  • Kamini Thakare, project staff, IIT Bombay
  • Deepu A, project staff, IIT Bombay

 Research Interest

  • Sensor platform development :
  • A highly sensitive refractive index sensor and evanescent wave absorbance based sensor is developed by fabricating U-bent optical fiber with very low bend diameters. A simple technique for Plastic optical fiber bending and decladding has been developed. Optimization studies have been carried out theoritically and experimentally and these probes have been utilized for refractive index, force and level sensing applications,...Readmore..

  • Nanomaterials and surface chemistry:
  • Plasmonic nanomaterials such as gold and silver, with their high extinction coefficient and their sensitivity to the refractive index of the surrounding medium, are useful labels for evanescent wave absorbance based sensors. Preparation, characterization, bio-conjugation and surface immobilization of these nanomaterials onto silica or plastic U-bent optical fiber probe surface is a challenge and several protocols have been utilized successfully by our group,...Readmore...

  • Protein and DNA detection:
  • Detection of biomarkers such as proteins and nucleic acids at very low concentrations is achieved by performing sandwich immunoassays using U-bent optical fiber sensors. Several protocols for efficient analyte detection, reduction of non-specific binding, increased sensitivity using plasmonic bio-conjugates have been developed. There is ongoing research in this field to reach lower limits of detection with better sensitivity and repeatability,...Readmore...

  • Pathogen detection:
  • Pathogens absorb light at 280 nm. The U-bent probe, with its increased depth of penetration, can detect the presence of pathogens on the surface, by evanescent wave absorbance measured at 280 nm. Research is being carried out to use suitable bioreceptors and detect target molecules and pathogens present in sample,....Readmore...

  • Device development and microfluidics:
  • Device development towards large scale repeatable fabrication of U-bent fiber optic refractive index sensors; array sensors, distributed sensors, hand-held detectors are ongoing. Research is also carried out towards integration of U-bent optical fiber sensors with microfluidic devices fabricated in-house,...Readmore...