With an interdisciplinary background of nano-science and biotechnology, my research interest lies in exploring nano-enabled approaches for targeted therapeutic and diagnostic pre-clinical interventions. In my present role as Postdoctoral Researcher, I am engaged in synthesis, characterization and bio-evaluation of diverse nano formulations for ultrasound assisted targeted delivery of diagnostic nanomaterials as well as microRNA/suicide genes to orthotopic tumor models. Prior to my affiliation with Stanford, I played the role of Head of Research and Development at E-Spin Nanotech Pvt. Ltd. where I led projects to develop nanofiber based masks, diagnostic kits and devices. I believe that over the years of my interdisciplinary research experience in industry as well as academy, I have gained a holistic research aptitude with translation significance.

Honors & Awards

  • GYTI - Young Innovator Award -2019, DST -BIRAC (Gov. of India) (Jun 2019)
  • Best Graduate Project, TNSCST - (Gov of TN, India) (Dec 2010)

Professional Education

  • Doctor of Philosophy, Indian Institute of Technology, Roorkee (2017)
  • Master of Technology, Indian Institute of Technology, Roorkee (2012)
  • Bachelor of Technology, Anna University (2010)

Stanford Advisors

Current Research and Scholarly Interests

I strongly believe that the toughest challenges on the face of the earth is often addressed by the strengths of inter-disciplinary science. In sight of such promises, I specialized in the field of biotechnology and nanotechnology and thrive on research at the crossroads of these two emerging fields of science. Over the course of my research, I have learnt diverse techniques and procedures of diagnostic and therapeutic nanomaterial synthesis, characterization and bioevaluation (invitro & invivo).

Lab Affiliations

All Publications

  • Ultrasound Triggered Co-Delivery of Therapeutic MicroRNAs and a Triple Suicide Gene Therapy Vector by Using Biocompatible Polymer Nanoparticles for Improved Cancer Therapy in Mouse Models ADVANCED THERAPEUTICS Kumar, S., Wang, H., Telichko, A. V., Natarajan, A., Bettinger, T., Cherkaoui, S., Massoud, T. F., Dahl, J. J., Paulmurugan, R. 2021
  • Acoustically Driven Microbubbles Enable Targeted Delivery of microRNA-Loaded Nanoparticles to Spontaneous Hepatocellular Neoplasia in Canines ADVANCED THERAPEUTICS Kumar, S., Telichko, A. V., Wang, H., Hyun, D., Johnson, E. G., Kent, M. S., Rebhun, R. B., Dahl, J. J., Culp, W. N., Paulmurugan, R. 2020
  • SP94-Targeted Triblock Copolymer Nanoparticle Delivers Thymidine Kinase-p53-Nitroreductase Triple Therapeutic Gene and Restores Anticancer Function against Hepatocellular Carcinoma in Vivo. ACS applied materials & interfaces Sukumar, U. K., Rajendran, J. C., Gambhir, S. S., Massoud, T. F., Paulmurugan, R. 2020


    Gene-directed enzyme-prodrug therapy (GDEPT) is a promising approach for cancer therapy, but it suffers from poor targeted delivery in vivo. Polyethylenimine (PEI) is a cationic polymer efficient in delivering negatively charged nucleic acids across cell membranes; however, it is highly toxic in vivo. Hence, we efficiently reduced PEI toxicity without compromising its transfection efficiency by conjugating it with poly(d,l-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) as triblock copolymers through a multistep synthetic process. The synthesized nanoparticles showed efficient delivery of loaded nucleic acids to tumor cells in vitro and in vivo in mice. We used this nanoparticle to deliver a rationally engineered thymidine kinase (TK)-p53-nitroreductase (NTR) triple therapeutic gene against hepatocellular carcinoma (HCC), where p53 tumor suppressor gene is mutated in more than 85% of cancers. TK-p53-NTR triple gene therapy restores p53 function and potentiates cancer cell response to delivered prodrugs (ganciclovir (GCV) and CB1954). We used SP94 peptide-functionalized PLGA-PEG-PEI nanoparticles for the optimal delivery of TK-p53-NTR therapeutic gene in vivo. The nanoparticles prepared from the conjugated polymer showed high loading efficiency for the DNA and markedly enhanced TK-NTR-mediated gene therapy upon the simultaneous coexpression of p53 by the concurrent rescue of the endogenous apoptotic pathway in HCC cells of both p53-mutant and wild-type phenotypes in vitro. In vivo delivery of TK-p53-NTR genes by SP94-targeted PLGA-PEG-PEI NP in mice resulted in a strong expression of suicide genes selectively in tumors, and subsequent administration of GCV and CB1954 led to a decline in tumor growth, and established a superior therapeutic outcome against HCC. We demonstrate a highly efficient approach that exogenously supplements p53 to enable synergy with the outcome of TK-NTR suicide gene therapy against HCC.

    View details for DOI 10.1021/acsami.9b20071

    View details for PubMedID 32048820

  • Intranasal delivery of targeted polyfunctional gold-iron oxide nanoparticles loaded with therapeutic microRNAs for combined theranostic multimodality imaging and presensitization of glioblastoma to temozolomide. Biomaterials Sukumar, U. K., Bose, R. J., Malhotra, M., Babikir, H. A., Afjei, R., Robinson, E., Zeng, Y., Chang, E., Habte, F., Sinclair, R., Gambhir, S. S., Massoud, T. F., Paulmurugan, R. 2019; 218: 119342


    The prognosis for glioblastoma (GBM) remains depressingly low. The biological barriers of the brain present a major challenge to achieving adequate drug concentrations for GBM therapy. To address this, we explore the potential of the nose-to-brain direct transport pathway to bypass the blood-brain barrier, and to enable targeted delivery of theranostic polyfunctional gold-iron oxide nanoparticles (polyGIONs) surface loaded with therapeutic miRNAs (miR-100 and antimiR-21) to GBMs in mice. These nanoformulations would thus allow presensitization of GBM cells to the systemically delivered chemotherapy drug temozolomide (TMZ), as well as in vivo multimodality molecular and anatomic imaging of nanoparticle delivery, trafficking, and treatment effects. First, we synthesized GIONs coated with beta-cyclodextrin-chitosan (CD-CS) hybrid polymer, and co-loaded with miR-100 and antimiR-21. Then we decorated their surface with PEG-T7 peptide using CD-adamantane host-guest chemistry. The resultant polyGIONs showed efficient miRNA loading with enhanced serum stability. We characterized them for particle size, PDI, polymer functionalization, charge and release using dynamic light scattering analysis, TEM and qRT-PCR. For in vivo intranasal delivery, we used U87-MG GBM cell-derived orthotopic xenograft models in mice. Intranasal delivery resulted in efficient accumulation of Cy5-miRNAs in mice treated with T7-targeted polyGIONs, as demonstrated by in vivo optical fluorescence and MR imaging. We measured the therapeutic response of these FLUC-EGFP labelled U87-MG GBMs using bioluminescence imaging. Overall, there was a significant increase in survival of mice co-treated with T7-polyGIONs loaded with miR-100/antimiR-21 plus systemic TMZ, compared to the untreated control group, or the animals receiving non-targeted polyGIONs-miR-100/antimiR-21, or TMZ alone. Once translated clinically, this novel theranostic nanoformulation and its associated intranasal delivery strategy will have a strong potential to potentiate the effects of TMZ treatment in GBM patients.

    View details for DOI 10.1016/j.biomaterials.2019.119342

    View details for PubMedID 31326657

  • Tumor Cell-Derived Extracellular Vesicle-Coated Nanocarriers: An Efficient Theranostic Platform for the Cancer-Specific Delivery of Anti-miR-21 and Imaging Agents. ACS nano Jc Bose, R. n., Uday Kumar, S. n., Zeng, Y. n., Afjei, R. n., Robinson, E. n., Lau, K. n., Bermudez, A. n., Habte, F. n., Pitteri, S. J., Sinclair, R. n., Willmann, J. K., Massoud, T. F., Gambhir, S. S., Paulmurugan, R. n. 2018


    MicroRNAs are critical regulators of cancer initiation, progression, and dissemination. Extensive evidence suggests that the inhibition of over-expressed oncogenic miRNA function can be a robust strategy for anticancer therapy. However, in vivo targeted delivery of miRNA therapeutics to various types of cancers remains a major challenge. Inspired by their natural synthesis and cargo delivery capabilities, researchers have exploited tumor cell-derived extracellular vesicles (TEVs) for the cancer-targeted delivery of therapeutics and theranostics. Here, we investigate a TEV-based nanoplatform for multimodal miRNA delivery and phototherapy treatments as well as the magnetic resonance imaging of cancer. We demonstrated loading of anti-miR-21 that blocks the function of endogenous oncogenic miR-21 over-expressed in cancer cells into and subsequent delivery by TEVs derived from 4T1 cells. We also produced Cy5-anti-miR-21-loaded TEVs from two other cancer cell lines (HepG2 and SKBR3) and confirmed their robust homologous and heterologous transfection efficiency and intracellular Cy5-anti-miR-21 delivery. Additionally, TEV-mediated anti-miR-21 delivery attenuated doxorubicin (DOX) resistance in breast cancer cells with a 3-fold higher cell kill efficiency than in cells treated with DOX alone. We then investigated TEVs as a biomimetic source for the functionalization of gold-iron oxide nanoparticles (GIONs) and demonstrated nanotheranostic properties of TEV-GIONs in vitro. TEV-GIONs demonstrated excellent T2 contrast in in vitro magnetic resonance (MR) imaging and resulted in efficient photothermal effect in 4T1 cells. We also evaluated the biodistribution and theranostic property of anti-miR-21 loaded TEV-GIONs in vivo by labeling with indocyanine green near-infrared dye. We further validated the tumor specific accumulation of TEV-GIONs using MR imaging. Our findings demonstrate that the distribution pattern of the TEV-anti-miR-21-GIONs correlated well with the tumor-targeting capability as well as the activity and efficacy obtained in response to doxorubicin combination treatments. TEVs and TEV-GIONs are promising nanotheranostics for future applications in cancer molecular imaging and therapy.

    View details for PubMedID 30346694

  • Synthesis and bio-evaluation of xylan-5-fluorouracil-1-acetic acid conjugates as prodrugs for colon cancer treatment CARBOHYDRATE POLYMERS Sauraj, Kumar, S., Gopinath, P., Negi, Y. 2017; 157: 1442–50


    In the present study, xylan-5-fluorouracil-1-acetic acid (Xyl-5-FUAC) conjugates as colon specific prodrugs were synthesized and evaluated by in-vitro release study. The chemical stability of the conjugates was performed in acidic (pH 1.2) and basic buffers (pH 7.4), which showed their stability in upper gastrointestinal tract. The in-vitro drug release profiles of the conjugates were studied in the presence of rat's gastrointestinal contents. The results showed that the low amounts of drug 3-4% and 5-7% were released in gastric and small intestine contents respectively, while 53-61% of the drug was released in cecum and colonic contents. The cytotoxicity studies of the conjugates were also evaluated on human colorectal cancer cell line (HTC-15 and HT-29), which showed that the conjugates are more cytotoxic than the free drug. Therefore the results reveal that Xyl-5-FUAC conjugates are potential candidates for colon specific drug delivery in the treatment of colonic cancer with minimal undesirable side effects.

    View details for DOI 10.1016/j.carbpol.2016.09.096

    View details for Web of Science ID 000391896800161

    View details for PubMedID 27987854

  • Multifunctional carbon dots as efficient fluorescent nanotags for tracking cells through successive generations JOURNAL OF MATERIALS CHEMISTRY B Bhushan, B., Kumar, S., Gopinath, P. 2016; 4 (28): 4862–71

    View details for DOI 10.1039/c6tb01178k

    View details for Web of Science ID 000379570000009

  • Bioactive Core-Shell Nanofiber Hybrid Scaffold for Efficient Suicide Gene Transfection and Subsequent Time Resolved Delivery of Prodrug for Anticancer Therapy ACS APPLIED MATERIALS & INTERFACES Sukumar, U., Packirisamy, G. 2015; 7 (33): 18717–31


    Nanofiber scaffold's ability to foster seemingly nonexistent interface with the cells enables them to effectively deliver various bioactive molecules to cells in the vicinity. Among such bioactive molecules, therapeutically active nucleic acid has been the most common candidate. In spite of such magnanimous efforts in this field, it remains a paradox that suicide gene delivery by nanofibers has never been sought for anticancer application. To investigate such a possibility, in the present work, a composite core-shell nanofiberous scaffold has been realized which could efficiently transfect suicide gene into cancer cells and simultaneously deliver prodrug, 5-Fluorocytosine (5-FC) in a controlled and sustained manner. The scaffold's ability to instigate apoptosis by suicide gene therapy in nonsmall lung cancer cells (A549) was ascertained at both phenotypic and genotypic levels. A cascade of events starting from suicide gene polyplex release from nanofibers, transfection, and expression of cytosine deaminase-uracil phosphoribosyltransferase (CD::UPRT) suicide gene by A549; subsequent prodrug release; and its metabolic conversion into toxic intermediates which finally culminates in host cells apoptosis has been monitored in a time-dependent manner. This work opens up new application avenues for nanofiber-based scaffolds which can effectively manage cancer prognosis.

    View details for DOI 10.1021/acsami.5b05280

    View details for Web of Science ID 000360322000063

    View details for PubMedID 26234345

  • Controlled delivery of bPEI-niclosamide complexes by PEO nanofibers and evaluation of its anti-neoplastic potentials COLLOIDS AND SURFACES B-BIOINTERFACES Kumar, S., Gopinath, P. 2015; 131: 170–81


    Since the turn of the 21st century, nanofiber based drug delivery systems have evolved drastically to attain controlled and sustained delivery of various bioactive molecules. In spite of such efforts, the tangible interface existing between the target cells and the drug molecules could not be narrowed down. This drawback has been overcome in this work by realizing nanofiber based scaffold for delivery of polymer-drug complexes rather than just the drug. In course with this, in the present study a differentially cross-linkable bPEI-PEO (branched-polyethylenimine-poly(ethylene oxide)) based nanofiber is fabricated for tunable delivery of bPEI-niclosamide complexes. Hydrophilic bPEI-niclosamide complexes are pre-synthesized and stabilized by crosslinking agent, which were then incorporated into bPEI-PEO nanofibers by electrospinning. The niclosamide loaded nanofibers by virtue of bPEI moieties presence were then cross-linked to different degrees which in turn altered bPEI-niclosamide release profile. The release kinetics of bPEI-niclosamide complexes from nanofibers was elucidated further by Korsmeyer-Peppas model. Apart from this, the versatile nature of bPEI-PEO nanofibers was also validated for different drug loading concentration and extent of crosslinking. The fibers antitumor efficacy was then assessed against A549 (Non-small cell lung cancer cells) and U-87 MG (glioblastoma cells) at two different time points (at 48h and 96h) in order to realize the importance of release profile in manifestation of different therapeutic outcomes. Thus, this work endows niclosamide a new life for anticancer application which has remained elusive till date due to its hydrophobic nature.

    View details for DOI 10.1016/j.colsurfb.2015.04.063

    View details for Web of Science ID 000357354800023

    View details for PubMedID 25988281