2010 - 2015 (July): Scientist - MINTEK, Advanced Materials Division, Nanotechnology
2015 (August) - 2022: Senior Lecturer - UFS, Dept of Physics
2022 - Present: Associate Professor: UFS, Dept. of Physics
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EMAIL: harrisra@ufs.ac.za
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Nanomaterials for Health
In my research, through computational modelling, simulations and complimentary experimental work, I investigate the synthetic chemistry, magnetic characterization and biological applications of inorganic/organic - core/shell FexOy based magnetic nanoparticles as well as metal- and metal-oxide nanoparticles. Furthermore, I investigate the adsorption of different chemotherapy drugs and their concentrations onto Fe3O4 nanoparticles (to be employed as nanocarriers) within a Molecular Dynamics framework and Monte Carlo simulated annealing scheme. Bonding modes are investigated with reference to chemisorption, physisorption as well as hydrogen bonding in the context of bond strength (binding energy) as a function of both the drug molecule’s loading as well as a change in nanoparticle size. Density functional theory (DFT) simulations are also performed to investigate the conditions for charge transfer from the temozolomide surfactant via the highest occupied molecular orbitals (HOMO), lowest unoccupied molecular orbitals (LUMO) as well as the electrostatic potentials. From this the preferential sites for both electrophilic and nucleophilic attacks can be calculated. This is important, for example, when considering the interaction with the blood-brain barrier as this remains a major challenge in effective chemotherapy of brain metastases. Despite the variability in its barrier function within brain tumour lesions, most drugs are still prevented from effectively entering the brain. With our computational studies, we investigate the changes the chemotherapy drugs may undergo when interacting with the nano-drug-carrier, within the context of delivering it to the target area. We also investigate the detection of small molecules and the screening via SERS of various drugs to create an accurate judgement in emergent medical and forensic settings.
Quantum-materials for Energy & Micro-technologies.
Quantum-wells and -wires are a type of two- and one-dimensional structure which are extremely small in diameter. When their physical dimensions are in the order of hundreds of nm to only a few nm, these structures are called nanocrystals(NCs). NCs may be engineered into different types of one-dimensional architectures like nano- wires, - rods, - tubes and - belts. In the case of two-dimensional structures, they are known as quantum-wells. Materials engineered and synthesized into (NCs) exhibit different properties from their bulk counterparts, partly due to their increase in surface-to-volume ratio, and partly due to quantum confinement effects that alter their density of electronic states. Therefore, these types of NCs display different electronic properties when their dimensions are altered. In the case of nanowires, by altering their length as well as their widths, these structures’ electronic properties may be enhanced. Semiconducting NCs have distinctive physical and optical properties that make them ideal candidates for future electronic and optoelectronic devices Candidate materials have shown remarkable promise in making progress towards efficient solar energy harvesting and conversion to electrical energy. However, improving the efficiency of these solar devices still requires much work. It is therefore (globally) an ongoing field of research. Quantum devices such as quantum- wells, wires and dots are promising candidates for future energy applications. Photovoltaics and supercapacitors are two possible routes through which the demand for higher efficiency energy generators and storage mechanisms may be satisfied. In my most recent research via both computational-modelling-and-simulations as well as through complementary experimental work like electron beam lithography, we are developing a quantum well device that acts as both a photovoltaic cell as well as UV-detector.
Most Recent Journal Publications
- Modelling and simulation study of the influence of size and surface functionality on the stability of PEG-functionalized AgNPs; T. Ngake, M. Gulumian, S. Cronje and R.A. Harris; Molecular Simulation (2022), DOI: 10.1080/08927022.2022.2141809
- Computational study of the effect of size and surface functionalization on Au nanoparticles on their stability to study biological descriptors; S. Nqayi, M. Gulumian, S. Cronje, R.A. Harris; Journal of Molecular Modeling 28 (2022) 376.
- Simulation study on the physicochemical properties of Fe3O4 nanoparticles as drug delivery vehicles for dopamine replacement therapy of Parkinson’s Disease; RA Harris; Materials Today Communications 31 (103829)
- The PEGylated and non-PEGylated interaction of the anticancer drug 5-fluorouracil with paramagnetic Fe3O4 nanoparticles as drug carrier; RA Harris; Journal of Molecular Liquids 360, 119515
- Recent developments in computational and experimental studies of physicochemical properties of Au and Ag nanostructures on cellular uptake and nanostructure toxicity; T Ngake, S Nqayi, M Gulumian, S Cronjé, RA Harris; Biochimica et Biophysica Acta (BBA)-General Subjects, 130170
- Using the Isalos platform to develop a (Q) SAR model that predicts metal oxide toxicity utilizing facet-based electronic, image analysis-based, and periodic table derived …; MM Thwala, A Afantitis, AG Papadiamantis, A Tsoumanis, G Melagraki, LN Dlamini, CNM Ouma, P Ramasami, R Harris, Tomasz Puzyn, N Sanabria, I Lynch, M Gulumian; Structural Chemistry 33 (2), 527-538
- Laser Assisted Catalytic Growth of Silicon Nanowires Using Gold and Nickel Catalysts; S Nyembe, G Ndlovu, P Shumbula, R Harris, N Moloto, L Sikhwivhilu; Journal of Nanoscience and Nanotechnology 21 (10), 5260-5265
- Group-targeting SERS screening of total benzodiazepines based on large-size (111) faceted silver nanosheets decorated with zinc oxide nanoparticles; C Wang, X Xu, G Qiu, W Ye, Y Li, RA Harris, C Jiang; Analytical Chemistry 93 (7), 3403-3410
- Structural properties and luminescence dynamics of CaZrO 3: Eu 3+ phosphors; AK Kunti, N Patra, RA Harris, SK Sharma, D Bhattacharyya, SN Jha, ...; Inorganic Chemistry Frontiers 8, 821
- Selective synthesis of monodisperse CoO nanooctahedra as catalysts for electrochemical water oxidation; M Sarif, J Hilgert, I Khan, RA Harris, S Plana-Ruiz, M Ashraf, E Pu¨tz, ...; Langmuir 36 (46), 13804-13816
- Synthesis of silver incorporated lithium doped zinc oxide nanocomposites for in-vitro biorational evaluation of Candiasis and Cryptococcosis; KK Nair, RA Harris, B Viljoen, HC Swart, UK Aravind, CT Aravindakumar; Applied Surface Science 506, 144800
- Computational study of ZIF-8 analogues with electron donating and withdrawing groups for CO2 adsorption; CW Tsai, EHG Langner, RA Harris; Microporous and Mesoporous Materials 288, 109613
- Chemotherapy drug temozolomide adsorbed onto iron-oxide (Fe3O4) nanoparticles as nanocarrier: A simulation study; RA Harris; Journal of Molecular Liquids 288, 111084
- Biomolecular assisted synthesis and mechanism of silver and gold nanoparticles; S Samanta, S Agarwal, KK Nair, RA Harris, H Swart; Materials Research Express 6 (8), 082009
- Surface enhanced Raman scattering with methyl-orange on Ag-TiO2 nanocomposites: A computational investigation; RA Harris, J Prakash; Journal of Molecular Graphics and Modelling 87, 220-226
- Photoluminescence of metal-imidazolate complexes with Cd (II), Zn (II), Co (II) and Ni (II) cation nodes and 2-methylimidazole organic linker; CW Tsai, RE Kroon, HC Swart, JJ Terblans, RA Harris; Journal of Luminescence 207, 454-459
- Local structure and spectroscopic properties of Eu3+ -doped BaZrO3; HCS Arup K. Kunti, Nirmelaendu Patra, Richard A. Harris, Shailendra K ...; Inorganic Chemistry 58, 3073-3089
- Optimizing the binding energy of the surfactant to iron oxide yields truly monodisperse nanoparticles; H Sharifi Dehsari, RA Harris, AH Ribeiro, W Tremel, K Asadi; Langmuir 34 (22), 6582-6590
- Synthesis and evaluation of optical and antimicrobial properties of Ag-SnO2 nanocomposites; KK Nair, P Kumar, V Kumar, RA Harris, RE Kroon, B Viljoen, ...; Physica B: Condensed Matter 535, 338-343
- Computational and experimental evaluation of selective substitution of thiolated coumarin derivatives on gold nanoparticles: Surface enhancing Raman scattering and …; M Mlambo, RA Harris, P Mashazi, M Sabela, S Kanchi, LM Madikizela, ...; Applied Surface Science 396, 695-704
- Modeling the band gap of CdS quantum well structures; RA Harris, JJ Terblans; Physica E: Low-dimensional Systems and Nanostructures 84, 415-422
- Platonic gold nanocrystals: Formation of icosahedron and decahedron nanostructures through twining mechanism; S Nyembe, S Mpelane, P Shumbula, R Harris, N Moloto, L Sikhwivhilu; Journal of Nanoscience and Nanotechnology 16 (9), 9832-9837
- Synthesis, characterization and multifunctional properties of plasmonic Ag–TiO2 nanocomposites; J Prakash, P Kumar, RA Harris, C Swart, JH Neethling, AJ van Vuuren, ...; Nanotechnology 27 (35), 355707
- Embedded plasmonic nanostructures: synthesis, fundamental aspects and their surface enhanced Raman scattering applications; J Prakash, RA Harris, HC Swart; International Reviews in Physical Chemistry 35 (3), 353-398
- Synthesis, characterization and multifunctional properties of plasmonic Ag–TiO2 nanocomposites; P Jai, P Kumar, RA Harris, C Swart, JH Neethling, A Janse van Vuuren, ...; Nanotechnology 27 (35), 355707
- Qualitative analysis of some alkanethiols on Au nanoparticles during SERS; RA Harris, M Mlambo, PS Mdluli; RSC advances 6 (15), 12131-1214
- Engineered inorganic/organic-core/shell magnetic FexOy nanoparticles with oleic acid and/or oleylamine as capping agents; R Anthony Harris, H van der Walt, P Morgan Shumbula; Current Pharmaceutical Design 21 (37), 5369-5388
- Exciton binding energy in an infinite potential semiconductor quantum well–wire heterostructure; R Harris, J Terblans, H Swart; Superlattices and Microstructures 86, 456-466
- Analysis of the interaction of surfactants oleic acid and oleylamine with iron oxide nanoparticles through molecular mechanics modeling; RA Harris, PM Shumbula, H van der Walt; Langmuir 31 (13), 3934-3943
- Cytotoxicity effects of citrate, glucose and cetyltrimethyl ammonium chloride-capped silver nanoparticles in lung epithelial carcinoma cells (A549); P Shumbula, R Harris, S Nyembe, FK Keter, L Sikhwivhilu, R Tshikhudo; Materials Today: Proceedings 2 (7), 4118-4124
- Molecular dynamics study on iron oxide nanoparticles stabilised with Sebacic Acid and 1, 10-Decanediol surfactants; RA Harris, H Van der Walt, PM Shumbula; Journal of Molecular Structure 1048, 18-26
Group-Targeting SERS Screening of Total Benzodiazepines Based on Large-Size (111) Faceted Silver Nanosheets Decorated with Zinc Oxide Nanoparticles
- Changding Wang, Xiaohui Xu, Guoyu Qiu, Weichun Ye, Yumin Li, Richard A. Harris, and Chaoyang Jiang
Most Recent Conference Oral & Poster Presentations
R.A. Harris , INVITED - "Hydrocarbon Sensors" - 3rd International "Nano Carbon" Workshop in South Africa, Johannesburg, 14 January - 15 January 2016
R.A. Harris, M. Mlambo, P.S. Mdluli, (2016) - "Qualitative analysis of some alkanethiols on Au nanoparticles during SERS for early cancer detection" - The 6th International Conference on Nanoscience and Nanotechnology in Africa, South Africa, Johannesburg, 3 - 6 April 2016
S. Nyembe, S. Mpelane, P. Shumbula, R.A. Harris, N. Moloto, L. Sikhwivhilu, INVITED (2016)- "Crystal Growth and Properties of Indium Phosphide Nanowires" - 3rd International "Nano Carbon" Workshop in South Africa, Johannesburg, 14 January - 15 January 2016
S. Nyembe, N. Moloto, R.A. Harris, P. Shumbula, L. Sikhwivhilu (2016) - "Comparison of using a Metallic and and Oxide Precursor in Synthesizing Indium Phosphide Nanowires through Chemical Vapour Deposition." - The 6th International Conference on Nanoscience and Nanotechnology in Africa, South Africa, Johannesburg, 3 - 6 April 2016
S. Nyembe, P. Shumbula, R.A. Harris, N. Moloto, L. Sikhwivhilu (2016) - "Sorption of NO, CO and CH4 on indium phosphide nanowires supported with molecular modelling", Cape Town, South Africa, 20 - 21 June 2016.
R.A. Harris - "Developing Iron Oxide nanoparticle Biosensors via Simulations and Modelling" - The 61st Annual Conference of the South African Institute of Physics, Cape Town, 4 - 8 July 2016.
R.A. Harris, PLENARY - "The mechanics of surface enhanced Raman spectroscopy on nanosystems - a theoretical investigation" - 1st Nanoscience Symposium of the National Nanoscience Postgraduate Teaching and Training Platform, Cape Town, South Africa, 3 October 2016.
R.A. Harris – “SERS through selective substitution of thiolated coumarin derivatives on Au NPS” – 7th South African Conference on Photonic Materials, Amanzi, South Africa, 27-31 March 2017.
K.K. Nair, J. Prakash, V.Kumar, P. Kumar, R.A. Harris, R.E.Kroon, B. Viljoen, H.C. Swart – “Synthesis of Ag-SnO2 nanocomposites and evaluation of optical photoluminescence and antimicrobial properties” - – 7th South African Conference on Photonic Materials, Amanzi, South Africa, 27-31 March 2017.
R.A. Harris, C.-W. Tsai – “Designing nanomaterials through modelling and simulations” – Joint SA-Sweden Research Collaboration Workshop, Linköping Sweden, 25-26 September 2017.
R.A. Harris, INVITED – “SERS and energy/charge transfer for photoactive materials” – 63rd Annual South African Institute of Physics WORKSHOP: PHOTONIC MATERIALS, Bloemfontein, South Africa, 25-29 June 2018.
H.F. Dehsari, R.A. Harris, A.H. Ribeiro, W. Tremel, K. Asadi – “Controlling iron-oxide nanoparticle size with nanometer precision to synthesize monodispersed particles: a theoretical and experimental investigation” - 63rd Annual South African Institute of Physics Bloemfontein, South Africa, 25-29 June 2018.
S.P. Lara, J.J. Terblans, R.A. Harris – “Fabrication and characterization of nanowire-template on silicon-substrate spin coated with poly(methyl methacrylate) resists.” - 63rd Annual South African Institute of Physics, Bloemfontein, South Africa, 25-29 June 2018.
S. Nqayi, H.C. Swart, P.M. Shumbula, R.A. Harris – “Quantum size effect on structural and optical properties of thioglycerol (TG) capped CdS nanoparticles - 63rd Annual South African Institute of Physics, Bloemfontein, South Africa, 25-29 June 2018.
C.-W. Tsai, E.H.G. Langner, J.J. Terblans, H.C. Swart, R.A. Harris – “Computational study of ZIF with functional groups for CO2 absorption” - 63rd Annual South African Institute of Physics, Bloemfontein, South Africa, 25-29 June 2018.
R.A. Harris – “Monodisperse Supermaramagnetic Nanoparticles” - Joint South Africa-Sweden Research Collaboration Workshop on Improving performance of wide-bandgap materials, Visby, Sweden, 13th - 15th of August 2018
R.A. Harris, K. Asadi, H.S. Dehsari, A.H.Ribeiro – “Simulating nanoparticles for nanometer precision” – NANOSMAT AFRICA, Cape Town, South Africa, 19-23 November 2018.
S. Nqayi, H.C. Swart, R.A. Harris – “Photocatalytic water splitting with CdS quantum dots”, – NANOSMAT AFRICA, Cape Town, South Africa, 19-23 November 2018.
C.-W. Tsai, R.A. Harris – “Zeolitic Imidazolate Framework nanomaterial with functional groups for CO2 absorption: a computational study” - – NANOSMAT AFRICA, Cape Town, South Africa, 19-23 November 2018.
R.A. Harris et. al. – “Magnetic monodispersed nanoparticles as drug carriers:a simulation and experimental study of Fe3O4 and temozolomide with nanometer precision size control” – Nano M&D 2019, International Conference, Paestum, Italy, 4-8 June 2019.
C.-W. Tsai, E.H.G. Langner, R.A. Harris et al. – “Photoluminescence of Metal (II) Imidazolate complexes (ZIFs) for sensing alcohols” - Nano M&D 2019, International Conference, Paestum, Italy, 4-8 June 2019.
C.-W. Tsai, Ernie H.G. Langner, R.A. Harris – “Zeolitic Imidazolate Framework nanomaterial with functional groups for CO2 adsorption” – FS Physchem, 2019, Bloemfontein, September 2019
R.A. Harris – “SPION drug carriers:a simulation and experimental investigation” – Flemish (FWO) / South Africa research Collaboration Programme, Ghent University, Belgium, 27 – 30 October 2019
R.A. Harris (INVITED) – “Introduction to Computational Modelling” – Computational Toxicology in Risk Assessment, North West University, South Africa, 27 – 31 January 2020.
Most Recent Conference Proceedings
R.A. Harris, J.J. Terblans, H.C. Swart, Materials Today Proceedings, 2015, 2, 4100, “Microstructure engineering of binary alloy thin films through monte Carlo simulation of Pt/Al thin-film precipitate-evolution”.
R.A. Harris, H. van der Walt, Materials Today Proceedings, 2015, 2, 4167, “Simulated Adsorbance of 11-Aminoundecanoic Acid to Stabilise Fe3O4 nanoparticles”.
S. Nyembe, S. Mpelane, P.M. Shumbula, R.A. Harris, N. Moloto, L. Sikhwivhilu, Materials Today Proceedings, 2015, 2, 4149, “The Effects of gold seeds stabilizing agent on gold nanostructure morphologies”.
P. Shumbula, R.A. Harris, S. Nyembe, F.K. Keter, L. Sikhwivhilu, R. Tshikhudo, Materials Today Proceedings, 2015, 2, 4118, “Cytotoxicity effects of citrate, glucose and cetyltrimethyl ammonium chloride-capped silver nanopartilces in lung epithelial carcinoma cells (A549)”.