Dhiraj Kumar, PhD

I am a nanomaterial scientist with expertise in surface engineered inorganic and organic nanoparticles for various biomedical applications. I have degrees in Chemistry and Nanobiotechnology with a Ph.D. in Biomedical engineering. My Ph.D. dissertation focused on PEG and BODIPY co-functionalized gold nanoparticles for drug delivery applications. During my 1st postdoctoral position at Christchurch Women Hospital, I optimized the conditions and formulated LHRH conjugated gold nanoparticles for active targeting of ovarian cancer for in vitro and in vivo models. Also, we translated the formulation for biomedical imaging using novel MARS spectral CT imaging. After moving to USA as a Postdoctoral Associate, I gained expertise in biodegradation of dental polymer and we investigated a novel flipped ester design that restricted bio/degradation when exposed to accelerated aging model, pure cholesterol enzyme and bacterial cells. Also, we investigated the role of inorganic polyphosphate (PolyP) in dental caries by attenuation of phosphate uptake and PolyP accumulation in oral bacterial cells (Rothia dentocariosa-Rd). At my current position we are investigating the flow of phosphate from demineralized tooth leading to PolyP synthesis and accumulation using P32 nucleotide in Rd bacterial cells. Also, I am developing magnetic, lipid and mesoporous silicate nanoparticles for biomedical applications.

I am interested in developing surface engineered nanoparticulate formulation and nanoparticle-polymer composite for biomedical applications. The current focus is on organic and inorganic nanoparticles as therapeutic and diagnostic agent for cancer targeting and mesoporous metal silicate nanoparticles for drug, molecular delivery and alter cell response for therapeutic application in medicine and dentistry.

1.  LHRH conjugated gold nanoparticles assisted efficient ovarian cancer targeting evaluated via spectral photon-counting CT imaging: A proof-of-concept research, Dhiraj Kumar*, Mahdieh Moghiseh*, Kenny Chitcholtan, Chiara Lowe, Isha Mutreja, Ajeet Kaushik, Anthony Butler, Nigel Anderson, Peter Sykes, Aamir Raja 2023 (Journal of Materials Chemistry B RSC, IF-7.571), DOI: 10.1039/D2TB02416K).
2. Fluoride and Gallein Inhibit Polyphosphate Accumulation by Oral Pathogen Rothia dentocariosa, Dhiraj Kumar, Subhrangshu Mandal, Akbar Khan, Jake V. Bailey, Beverly E. Flood, Robert S. Jones 2023 (Letters in Applied Microbiology, IF-2.813), DOI: 10.1093/lambio/ovad017).
3. Gelatin methacryloyl hydrogels for musculoskeletal tissue regeneration, Yang-Hee Kim, Jonathan I Dawson, Richard O.C. Oreffo, Yasuhiko Tabata, Dhiraj Kumar, Conrado Aparicio, Isha Mutreja 2022 (Bioengineering MDPI, IF–5.046), DOI: 10.3390/bioengineering9070332).
4. Methacrylate Polymers with 'Flipped External' Ester Groups: A Review, Dhiraj Kumar, Robert D Bolskar, Isha Mutreja, and Robert S Jones 2022 (Frontiers in Dental Medicine, DOI: 10.3389/fdmed.2022.923780).
5. Emerging Nanostructures in Dental Applications, Debarati Ghose* and Dhiraj Kumar* 2022 (Springer book chapter, DOI: https://link.springer.com/chapter/10.1007/978-981-19-1312-9_8).
6. Strontium- and peptide-modified silicate nanostructures for dual osteogenic and antimicrobial activity, Isha Mutreja, Dhiraj Kumar, Kami Hogan, Emily Campbell, Kim Mansky, Conrado Aparicio, 2022 (Biomaterials Advances (IF–8.457), DOI: 10.1016/j.bioadv.2022.212735).
7. Utilizing a degradation prediction pathway system to understand how a novel methacrylate derivative polymer with flipped external ester groups retains physico-mechanical properties following esterase exposure, Dhiraj Kumar, Debarati Ghose, Robert D Bolskar, Isha Mutreja, Conrado Aparicio, and Robert S Jones, 2022 (Dental Materials (IF–5.687), DOI: 10.1016/j.dental.2021.12.008).
8. Hybrid nanocoatings of antimicrobial peptides and silver nanoparticles for preservation of implant infections, Zhou Ye, Ting Sang, Kun Li, Nicholas G. Fisher, Isha Mutreja, Constanza Echeverria, Dhiraj Kumar, Zhen Tang, Conrado Aparicio. 2021 (Acta Biomaterialia (IF–8.947), DOI: 10.1016/j.actbio.2021.12.008).
9. A novel methacrylate derivative polymer that resists bacterial cell-mediated biodegradation, Dhiraj Kumar, Debarati Ghose, Robert D Bolskar, Isha Mutreja, and Robert S Jones. 2021 (Journal of Biomedical Materials Research B (IF–3.42), DOI: 10.1002/jbm.b.34972).
10. A novel dental polymer with a flipped external ester group design that resists degradation via polymer backbone preservation, Dhiraj Kumar, Robert D Bolskar, Sydney Malone, Isha Mutreja, Conrado Aparicio, and Robert S Jones. 2020 (ACS, Biomaterials Science & Engineering (IF–4.152), DOI: 10.1021/acsbiomaterials.0c00947).
11. Design and characterization of multi-functional strontium-gelatin nanocomposite bioinks with improved print fidelity and osteogenic capacity, Cesar R. Alcala-Orozco, Isha Mutreja, Xiaolin Cui, Dhiraj Kumar, Gary J. Hooper, Khoon S. Lim, Tim B.F. Woodfield. 2020 (Bioprinting (IF – 5.88), DOI: 10.1016/j.bprint.2019.e00073).

Presentations:

1. Addressing Biological Induced Failure of Dental Resin Composites through a New Polymer, Dhiraj Kumar, Oral Biology Seminar 2021-12-10 (Talk).
2. Bioactive Anti-infective Photocurable Hydrogel for Improved Durability of The Skin/implant Interface, Isha Mutreja; Dhiraj Kumar; Conrado Aparicio, ORS 2023.
3. ZnO-based nanocomposite hydrogel for enhanced periodontal regeneration and reducing inflammation, AADOCR/CADR 2023.
4. A flipped external ester group methacrylate macromer as a potential EGDMA alternative in dental formulations, Dhiraj Kumar, Robert D. Bolskar, Robert S Jones, BMES 12-15, October 2022. Poster
5. Multifunctional photocurable hydrogel for improved durability of the skin/implant interface, Isha Mutreja, Dhiraj Kumar, Conrado Aparicio, MHSRS 12-15, September 2022. Poster
6. Strontium-based nanocomposite hydrogel for enhanced periodontal regeneration and fighting infection, Isha Mutreja, Dhiraj Kumar, Conrado Aparicio, AADOCR/CADR March 2022.
7. A Flipped Ester group design-based methacrylate macromer for improved stability under hydrolytic and enzymatic conditions, Dhiraj Kumar, Debarati Ghose, Robert D. Bolskar, Isha Mutreja, Conrado Aparicio, Robert S Jones, Society for Biomaterials, April 20-23, 2021 (Rapid Fire Presentation).
8. Strontium – based nanocomposite hydrogels for Improved Anti-infective and Osteogenic Differentiation Capability, I Mutreja, D Kumar, T Nies, K Mansky, C Aparicio, SFB 2021. Poster
9. AMP-loaded mesoporous strontium silicates with improved bioactivity and antibacterial capability.
10. Dual-action AMP-loaded mesoporous strontium silicate nanostructures for aseptic periodontal regeneration IADR/AADR/CADR July 2021. 
11. A designer antimicrobial peptide: role of supramolecular peptide assembly and implications for the use as building block for potent antimicrobial biomaterials, Conrado Aparicio, Zhou Ye, Dhiraj Kumar, Alexandra C. Kobe, Ting Sang, Sergio Acosta and Janaki Khot, TERMIS Nov. 2021 Maastricht Netherlands.
12. Strontium-modified peptide-loaded silicate nanoparticles for enhanced osteogenesis and antimicrobial activity, Kami Hogan, Isha Mutreja, Dhiraj Kumar, Kirk Twaroski, Jakub Tolar and Conrado Aparicio, IADR 18-21 March 2020.
13. Ultra-small, highly stable, and cyto-compatible Silver Nanoparticles for Antimicrobial Coatings, Ting Sang, Zhou Ye, Constanza Echeverría, Kun Li, Nicholas Fischer, Isha Mutreja, Dhiraj Kumar, Zhen Tang, Conrado Aparicio, IADR, 18-21 March 2020.
14. AMP-loaded mesoporous strontium silicates with improved bioactivity and antibacterial capability, Isha Mutreja, Kami Hogan, Dhiraj Kumar, Conrado Aparicio, TMS 23-27 Feb. 2020. (Talk)

Grants:

1. The Unrecognized Role of Phosphate-accumulating Bacteria, NIH 2018 (Since 2021 with Prof. Robert S Jones).
2. Novel Polymer Matrix for Dental Application Phase II, SBIR 2018-21 (As a Postdoc with Prof. Robert S Jones).

Patents:

1. Oral bandage – hydrogel, Isha Mutreja, David Mei, Dhiraj Kumar. 2023 (under preparation).
2. A method for the detection and identification of diseased cells and pathogens in histological sections using fluorescent organically modified silica nanoparticles, Susmita Mitra, Amit K Dinda and Dhiraj Kumar (Amity University Patents – 1208 / DEL / 2009).
3. A Fluorescent core shell organically modified silica (ORMOSIL) nanoparticles-based detection probe and kit for Cryptococcus neoformans, Susmita Mitra, Dhiraj Kumar, Daman Saluja, Manish Sethi (Amity University Patents – 906 / DEL / 2009).