Areas of Interest/Specialization:

• Time-resolved techniques, Fluorescence in complex systems;
• Bio-molecular Interaction; Development of Fluorescence based Enzymatic Assay Method;
• Application of functionalized nanoconjugates in therapeutic applications.

In general, several aspects on the above-mentioned problems are monitored with steady state and time resolved fluorescence spectroscopy. Ultrafast photo-processes and solvent response towards the formation of the transient species are probed with transient absorption and fluorescence up-conversion techniques in collaboration with several research groups in India & abroad. The experimental results are often supported with ab-initio/DFT calculations, molecular docking and molecular dynamics (MD) simulation. Recently, we are interested in the development of non-covalently functionalized nanoconjugate system and assess their potentiality as drug delivery and drug repurposing agent in multiple disease domains, including neurodegenerative disorders.

Academic Experience:

• JSPS Postdoctoral Fellow: Kwansei Gakuin University, Japan (1997 - 1999)
• Postdoctoral Researcher: Katholieke University of Leuven, Belgium (1999 - 2000)
• Visiting Fellow: Department of Chemical Science, TIFR, Mumbai (2000 - 2001)
• Lecturer: Department of Chemistry, BITS, Pilani (2001 - 2003)
• JSPS Invitation Fellowship: Kwansei Gakuin University, Japan (2003), 3 months.
• Assistant Professor: Department of Chemistry, NEHU, Shillong (2003 - 2012)
• Visiting Professor C: Kwansei Gakuin University, Japan (2006), 2 months
• Associate Professor: Department of Chemistry, NEHU, Shillong (2012 - 2015)
• Professor: Department of Chemistry, NEHU, Shillong (2015 - onwards)

Academic affiliations 

Member of American Chemical Society (ACS), Indian Society for Radiation & Photochemical Sciences (ISRAPS), Fluorescence Society of India, Indian Photobiology Society etc.

Administrative Experience

• Member, University Court, NEHU, Shillong
• Member, Academic Council, NEHU, Shillong
• Member, School Board of Physical Sciences, NEHU, Shillong
• Member, Board of Studies in Chemistry, NEHU, Shillong
• Member, Departmental Research Committee, Department of Chemistry, NEHU, Shillong
• Member, School Board of Life Sciences, NEHU, Shillong

Research Projects

Research Projects Ongoing (01)

1. “Functionalized nanocarriers with surface active ionic ionic liquids for drug delivery and augmented protein activity” UGC-DAE-CSR, Govt. of India (2024 - ).

Research Projects Completed (09)

1. Excited state properties and relaxation dynamics of intramolecularly hydrogen bonded azo derivatives" Dept. of Science & Technology (DST), Govt. of India (2005 - 2008).
2. Spectroscopic characterization of intramolecular charge transfer type polarity sensors and their use in the study of protein - surfactant interaction" Council of Scientific & Industrial Research (CSIR), Govt. of India (2005 - 2008).
3. Construction and Multi-site Commissioning of Multiple Fluorescence Correlation Spectrometers (a single molecule biophotonic tool)" [as co-investigator, with Prof. S. Maiti of TIFR, Mumbai as chief-investigator], Dept. of Information & Technology (DIT), Govt. of India (2008 - 2011).
4. Spectroscopy and Dynamics of Photoinduced Processes in Homogeneous and Biomimetic Environments” University grants Commission (UGC), Govt. of India (2008 – 2011).
5. “Fluorescence Studies on Representative Intramolecular Photoprocesses in Homogeneous and Constrained Environments” Board of Research in Nuclear Sciences (BRNS), DAE, Govt. of India (2009 – 2012).
6. “Development of Ache-inhibitor for Alzheimer’s Disease: Screening, Designing, Synthesis and Biological validation using Chemical Library and North East Indian Plants” [as co-investigator, with Prof. K. Aguan of Biotechnology Dept., NEHU as principal investigator], Department of Biotechnology (DBT), Govt. of India (2011-2014).
7. “Spectrofluorimetric Investigation on Model Nitrogen Containing Heterocyclic Drugs and their Interaction with DNA Nucleotides” CSIR, Govt. of India (2012 – 2015).
8. Photophysical Studies on polypyridyl complexes: Towards the development of nanoscopic fluorescent targets, DST-SERB, Govt. of India (2019 - 2022).
9. “Study on anti-Alzheimer activity of coumarin based hybrid drugs: Synthesis and acetylcholinesterase inhibition assay” ICMR, Govt. of India (2022)

Group members 

I. Present members

• Ph.D ongoing: (4)
  i) Ms. Anindita Bhatta (aninditabhatta01@gmail.com); 
  ii). Mr. Deepak Chamlagai (dipakchamlagai1@gmail.com); 
  iii). Mr. Pynskhemborlang Tep Phanrang (pynskhemphanrang@gmail.com); 
  iv). Ms. Jahnabi Upadhyaya (jahnabiu@gmail.com)

II. Past members

• Research Associate (01)
  Dr. Dhiman Ray (DSK Post-Doctoral Fellow); E-mail: dhimanray1@gmail.com  
• Doctoral (Ph. D.) Students (12)

  1. Dr. T. Sanjoy Singh (takhelsingh@gmail.com): Spectroscopic investigation on photo-induced intramolecular charge transfer process of donor-acceptor systems in homogeneous and micro-heterogeneous environments (2010).

  2. Dr. N. S. Moyon (bebemoyon@gmail.com): Solvatochromism and photophysical properties of alloxazine derivatives in homogeneous solvents and supramolecular assemblies (2011). 

  3. Dr. (Mrs.) S. Phukan (smrita4m@gmail.com): Fluorescence Studies on Biologically Relevant Heterocyclic Systems in Homogeneous Medium and Supramolecular Assemblies (2014). 

  4. Dr. P. Gashnga (miki.gash@gmail.com): Combined Experimental and Theoretical Studies on Photoinduced Hydrogen Transfer Processes (2016).

  5. Dr. M. M Islam (islammuhai85@gmail.com): Fluorescence Based Studies on Drug-Receptor Interaction: Characterization of Acetylcholinesterase Inhibitors (2017). 

  6. Dr. V. K. Sonu (vikash9931@gmail.com): Fluorescence Based Investigation on the Effect of Nanoparticle on some Bi-molecular Conjugation Processes (2018).

  7. Dr. M A Rohman (rohmanmostofa@gmail.com): Fluorescence studies on            some organic molecules and their complexes with supramolecular hosts (2020).

  8. Dr. (Ms) P. Baruah (praya412@gmail.com): Spectroscopic Studies on the Modulatory Effect of Nano-bio interfaces on Some Selected Neurodegenerative and Mitochondrial Enzyme Activities (2022). 

  9. Dr. Rajkumar Imocha Singh (imocharajkumar@gmail.com): Development of functionalized nanoparticles and their applications in exploring bio-molecular milieu (2022).

  10. Dr. (Ms) Anindita Bhatta (aninditabhatta01@gmail.com): Spectroscopic Investigation om Fluorogenic Organic Molecules in Solution and Bio-mimicking Environments (2023).

  11. Dr. Dipak Chamlagai (dipakchamlagai1@gmail.com): Photophysical studies on nitrogen based aromatic heterocycles: Fluorescence modulation and tuning in different media (2024).

  12. Dr. Pynskhemborlang Tep Phanrang (pynskhemphanrang@gmail.com): Interaction of drug molecules with biocompatible hosts: A Physico-chemical study based on experimental and computational approach (2024). 

Publications

Total number of publications: 128

1. "Therapeutic Advantages of Nanoparticle Impregnated Lysozyme Conjugates towards Amyloid-β Fibrillation and Anti-microbial Activity" Jahnabi Upadhyaya, Imocha Rajkumar Singh, Bishal Pun, Hirak Jyoti Baishya, Sugam Kumar, S.R. Joshi, Sivaprasad Mitra, J. Phys. Chem. B, 2025. https://doi.org/10.1021/acs.jpcb.4c07261
2. “Bio-Nano synergy in therapeutic applications: Drug-Graphene Oxide nanocomposites for modulated acetylcholinesterase inhibition and radical scavenging” Pynskhemborlang Phanrang, Jahnabi Upadhyaya, Asit K. Chandra, Amrit Sarmah, Pavel Hobza, Kripamoy Aguan, Sivaprasad Mitra, J. Phys. Chem. B, 2024. https://doi.org/10.1021/acs.jpcb.4c03351
3. “Molecular Insights on the Conformational and Binding Behaviors of Human Serum Albumin Induced by Surface-Active Ionic Liquids” Dhiman Ray, Dipak Chamlagai, Sugam Kumar, Sutanu Mukhopadhyay, Suman Chakrabarty, Vinod Kumar Aswal, Sivaprasad Mitra, J. Phys. Chem. B, 2024. https://doi.org/10.1021/acs.jpcb.4c01915 
4. “Many-body Effects on Electronic Transport in Molecular Junctions: A Quantum Perspective” Amrit Sarmah, Pavel Hobza, Asit K. Chandra, Sivaprasad Mitra, Takahito Nakajima, ChemPhysChem, 2024, e202300938, DOI: 10.1002/cphc.202300938
5. “Fluorescence based studies on the interaction and characterization of surface-active ionic liquids with polarity sensitive intramolecular charge transfer probe” Dhiman Ray, Dipak Chamlagai, Sugam Kumar, Vinod K. Aswal, and Sivaprasad Mitra, Chem. Phys. Impact, 2023, xx, xxx-xxx. https://doi.org/10.1016/j.chphi.2023.100368
6. “Donor-acceptor functionalized coumarin derivatives: Synthesis, fluorescence modulation, interaction with human serum albumin and acetylcholinesterase inhibition activity” Dipak Chamlagai, Porag Bora, Anindita Bhatta, Jahnabi Upadhyaya, Pynskhemborlang Tep Phanrang, Utpal Bora, and Sivaprasad Mitra, J. Photochem. Photobiol. A: Chem. 2023, xxx, xx-xx. https://doi.org/10.1016/j.jphotochem.2023.115273
7. “Molecular Insights on the Modulated Acetylcholinesterase Inhibition Activity of Tacrine Adsorbed on Biocompatible Graphene Oxide” Pynskhemborlang T. Phanrang, Imocha Rajkumar Singh, Jahnabi Upadhyaya, Asit K. Chandra, and Sivaprasad Mitra, ChemistrySelect, 2023, xxx, xxx-xxx. https://doi.org/10.1002/slct.202301247 
8. “Modulated photophysical properties and sequestration of potent anti-acetylcholinesterase active coumarinyl dyes in human serum albumin” Anindita Bhatta, Prayasee Baruah, Pynskhemborlang T. Phanrang, Grace Basumatary, Ghanashyam Bez, and Sivaprasad Mitra, Dyes and Pigments, 2023, xxx, xx-xx. https://doi.org/10.1016/j.dyepig.2022.110871
9. “Combined Experimental and Computational Studies on the Photophysical Properties of Systematically Substituted Polypyridyl Based Ligands on a Benzene Core” Dipak Chamlagai, Pynskhemborlang Tep Phanrang, Lincoln Dkhar, K. Mohan Rao, and Sivaprasad Mitra, J. Photochem. Photobiol. A: Chem. 2023, 435, xx-xx. https://doi.org/10.1016/j.jphotochem.2022.114330
10. "Therapeutic Opportunities of Surface-Active Ionic Liquids: A Case Study on Acetylcholinesterase, Citrate Synthase and HeLa Cell Lines” Prayasee Baruah, Dhiman Ray, Ibemhanbi Konthoujam, Abhinandan Das, Suman Chakrabarty, Kripamoy Aguan, and Sivaprasad Mitra, New Journal of Chemistry, 2022, 46, 20419-20432. https://doi.org/10.1039/D2NJ04365C
11. “Modulation of drug binding ability and augmented enzymatic activity of lysozyme stabilized in presence of surface-active ionic liquids” Dhiman Ray, Imocha Rajkumar Singh, Anindita Bhatta, Abhinandan Das, Suman Chakrabarty, and Sivaprasad Mitra, J. Mol. Liq. 2022, 367, xx-xx. https://doi.org/10.1016/j.molliq.2022.120356
12. “Iodine(III)-promoted regioselective and efficient synthesis of β-triazolyl BODIPYs for the selective recognition of nickel ion and bovine serum albumin” Bintu Kumar, Anindita Bhatta, Prakriti Saraf, Krishnan Rangan, Madhushree Sarkar, Sivaprasad Mitra, and Dalip Kumar, Dalton Trans. 2022, 51, 8169-8176. https://doi.org/10.1039/D2DT00946C
13. “Modulated Antimicrobial Activity and Drug-Protein Interaction Ability of Zinc Oxide and Cadmium Sulfide Nanoparticles: Effect of Doping with Few First-Row Transition Metals” Imocha Rajkumar Singh, Upashna Chettri, Piyali Maiti, Anup K. Ghosh, S. R. Joshi and Sivaprasad Mitra, J. Cluster Sci. 2022. https://doi.org/10.1007/s10876-022-02257-y
14. "Auxiliary Therapeutic Role of Cholinergic Agents: Mechanistic Insights into the Antioxidant Behavior of AD Drugs towards Reversing DNA Oxidative Stress" Pynskhemborlang Tep Phanrang, Prayasee Baruah, Asit K. Chandra, and Sivaprasad Mitra, J. Phys. Chem. A, 2022. https://doi.org/10.1021/acs.jpca.1c09146
15. "Elevated Fibrinogen Level Reduces Therapeutic Efficiency of AD Drugs: Biophysical Insights on the Interaction of FDA Approved Cholinesterase Inhibitors with Human Fibrinogen" Prayasee Baruah, Debojit Paul, Jitesh Doshi, and Sivaprasad Mitra, J. Phys. Chem. B, 2022, 126, 30 – 43. https://doi.org/10.1021/acs.jpcb.1c07495
16. "Deciphering Spectroscopic and Structural Insights into the Photophysical Behavior of 2, 2'-Dipyridylamine: An Efficient Environment Sensitive Fluorescence Probe" Mostofa Ataur Rohman, Pynskhemborlang Tep Phanrang, Dipak Chamlagai and Sivaprasad Mitra, J. Phys. Chem. A, 2021, 125, 6964-6975. https://doi.org/10.1021/acs.jpca.1c04772
17. “Cholinergic drugs bind at minor groove and reverse induced oxidative stress of calf thymus DNA: A new perspective towards an unexplored therapeutic efficacy” Prayasee Baruah, Pynskhemborlang Tep Phanrang, Ibemhanbi Konthoujam, Kripamoy Aguan, and Sivaprasad Mitra, New Journal of Chem., 2021, 45, 13925 – 13933. https://doi.org/10.1039/D1NJ01911B
18. “Dietary polyphenols inhibit plasma protein arabinosylation: Biomolecular interaction of genistein and ellagic acid with serum albumins” Imocha Rajkumar Singh, Semen O. Yesylevskyy, and Sivaprasad Mitra, Biophys. Chem., 2021. https://doi.org/10.1016/j.bpc.2021.106651
19. “Sulfonylurea class of anti-diabetic drugs inhibit acetylcholinesterase activity: Unexplored auxiliary pharmacological benefit towards Alzheimer’s Disease” Prayasee Baruah, Abhinandan Das, Debojit Paul, Suman Chakrabarty, Kripamoy Aguan, and Sivaprasad Mitra, ACS Pharmacology & Translational Science, 2021, 4, 193 – 205. https://doi.org/10.1021/acsptsci.0c00168
20. “Modulation of enzyme activity at nano-bio interface: A case study with acetylcholinesterase and citrate synthase adsorbed on colloidal metal nanoparticles” Prayasee Baruah, Semen O. Yesylevskyy, Kripamoy Aguan, and Sivaprasad Mitra, J. Mol. Liq., 2021, xx, xx – xx. https://doi.org/10.1016/j.molliq.2020.115201
21. "Fluorescence solvatochromism and modulated anticholinergic activity of novel coumarin compounds sequestered in human serum albumin nanocavities" Mostofa Ataur Rohman, Prayasee Baruah, Deboshikha Bhattacharjee, B. Myrboh, and Sivaprasad Mitra, New Journal of Chem., 2019, 43, 18713-18725. DOI: 10.1039/C9NJ03293B
22. “Excited state decay dynamics in 3-formyl-4-hydroxy benzoic acid: Understanding the global picture of an ESIPT driven multiple emissive species” Mostofa Ataur Rohman, Dipankar Sutradhar, Prakriti Ranjan Bangal, Asit K Chandra, and Sivaprasad Mitra, ChemistrySelect, 2019, 4, 6702 - 6712.
23. "Fluorescence solvatochromism and modulated anticholinergic activity of novel coumarin compounds sequestered in human serum albumin nanocavities" Mostofa Ataur Rohman, Prayasee Baruah, Deboshikha Bhattacharjee, B. Myrboh, and Sivaprasad Mitra, New Journal of Chem., 2019, DOI: 10.1039/C9NJ03293B.
24. “Specific solvent effect on the photophysical behavior of substituted chromones: A combined fluorescence, DFT and MD study” Mostofa Ataur Rohman, Prayasee Baruah, Semen O. Yesylevskyy, and Sivaprasad Mitra, Chemical Physics, 2019, 517, 67 – 79. DOI: 10.1016/j.chemphys.2018.09.042
25. “Interaction of caffeine and sulfadiazine with Lysozyme adsorbed at colloidal metal nanoparticle interface: Influence on drug transport ability and antibacterial activity”, Vikash K. Sonu, Imocha Rajkumar, Kaushik Bhattacharjee, S. R. Joshi, and Sivaprasad Mitra, J. Biomolecular Structure and Dynamics, 2018. DOI: 10.1080/07391102.2018.1426497.
26. “Serum albumin interaction with xanthine drugs at nano-bio interfaces: A combined multi-spectroscopic and molecular modelling approach”, Vikash K. Sonu, Mullah Muhaiminul Islam, Arun Bahadur Gurung, Atanu Bhattacharjee, and Sivaprasad Mitra, J. Mol. Liq., 2017, 242, 919 - 927.
27. “Photophysical behavior of systematically substituted (di-2-pyridylaminomethyl) benzene ligands and its Re(l) complexes: A combined experimental and theoretical approach”, M. A. Rohman, D. Sutradhar, S. Sangilipandi, K. Mohan Rao, Asit K. Chandra, Sivaprasad Mitra, J. Photochem. Photobiol. A: Chemistry, 2017, 341, 115 – 126.
28. “Cholinergic inhibitors replace thioflavin-T from acetylcholinesterase binding pocket: A potential fluorescence based molecular switch”, Mullah Muhaiminul Islam, and Sivaprasad Mitra, Chem. Phys. Letts. 2016, 664, 63 – 69.
29. “Lysozyme binding ability toward psychoactive stimulant drugs: Modulatory effect of colloidal metal nanoparticles” Vikash K. Sonu, Mullah Muhaiminul Islam, Mostofa Ataur Rohman, and Sivaprasad Mitra, Colloids and Surfaces B: Biointerfaces, 2016, 146, 514 – 522.
30. “Fluorescence properties and sequestration of peripheral anionic site specific ligands in bile acid hosts: Effect on acetylcholinesterase inhibition activity” Mullah Muhaiminul Islam, Kripamoy Aguan, and Sivaprasad Mitra, J. Photochem. Photobiol. B. Biology, 2016, 158, 192 – 201.
31. “Human serum albumin reduces the potency of acetylcholinesterase inhibitor based drugs for Alzheimer's disease” Mullah Muhaiminul Islam, Arun Bahadur Gurung, Atanu Bhatacharjee, Kripamoy Aguan, and Sivaprasad Mitra, Chemico-Biological Interactions 2016, 249, 1 – 9.
32. “Intramolecular charge transfer in coumarin based donor-acceptor systems: Formation of a new product through planar intermediate” S. Phukan, M. Saha, A. K. Pal, A.C. Bhasikuttan, and S. Mitra, J. Photochem. Photobiol. A: Chemistry, 2015, 303, 67 – 79.

Representative details of Invited Talks in Conference/Seminar/Workshop

Organization of Conferences/Symposia:

• Convener of “National Workshop on Fluorescence Correlation Spectroscopy & Biophotonics (FCS-2010)” held at North-Eastern Hill University, Shillong, Nov 8 -13, 2010.
• Vice-Chairman of the local organising committee for the BRNS-AEACI Ninth School on Analytical Chemistry (SAC-9) held at Atomic Minerals Directorate, NE Region, Shillong during Oct 27 – Nov 03, 2014.    
• Convener of National Seminar on contemporary Challenges in Chemistry (NSC3-2018) held at North-Eastern Hill University, Shillong, Nov 20-21, 2018.