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Dr David O. Oluwole



Research interests


Rodah C. Soy, Balaji Babu, David O. Oluwole, Njemuwa Nwaji, James Oyim, Edith Amuhaya, Earl Prinsloo, John Mack, Tebello Nyokong (2019)Photophysicochemical properties and photodynamic therapy activity of chloroindium(III) tetraarylporphyrins and their gold nanoparticle conjugates, In: Journal of porphyrins and phthalocyanines23(1-2)34pp. 34-45 World Scientific

Novel chloroindium(III) complexes of tetra(4-methylthiophenyl)porphyrin (2a) and tetra-2-thienylporphyrin (2b) dyes have been synthesized and characterized. The main goal of the project was to identify fully symmetric porphyrin dyes with Q-band regions that lie partially in the therapeutic window that are suitable for use in photodynamic therapy (PDT). 2a and 2b were found to have fluorescence quantum yield values

Nthabeleng Molupe, Balaji Babu, David O. Oluwole, Earl Prinsloo, Lizhi Gai, Zhen Shen, John Mack, Tebello Nyokong (2020)Photodynamic activity of 2,6-diiodo-3,5-dithienylvinylene-BODIPYs and their folate-functionalized chitosan-coated Pluronic (R) F-127 micelles on MCF-7 breast cancer cells, In: Journal of porphyrins and phthalocyanines24(5-7)pp. 973-984 World Scientific

A 2,6-diiodo-3,5-dithienylvinyleneBODIPY dye was prepared and encapsulated with folate-chitosan capped Pluronic (R) F-127 to provide drug delivery systems for photodynamic therapy (PDT). Moderately enhanced singlet oxygen quantum yields were observed for the dye encapsulation complexes in water. The in vitro dark cytotoxicity and photodynamic activity were investigated on the human breast adenocarcinoma (MCF-7) cell line. Minimal dark cytotoxicity was observed for the BODIPY dyes in 5% DMSO and when encapsulated in folate-functionalized chitosan-coated Pluronic (R) F-127 micelles, since the cell viability values are consistently greater than 80% over the 0-40 mu g.mL(-1) concentration range. Upon irradiation of the samples, significant cytocidal activity was observed for the encapsulation complex of a 2,6-diiodo-8-dimethylaminophenyl-3,5-dithienylvinyleneBODIPY dye with less than 50% viable cells observed at concentrations >= 20 mu g.mL(-1).

Francis Chindeka, Philani Mashazi, Jonathan Britton, David O. Oluwole, Sivuyisiwe Mapukata, Tebello Nyokong (2020)Fabrication of dye-sensitized solar cells based on push-pull asymmetrical substituted zinc and copper phthalocyanines and reduced graphene oxide nanosheets, In: Journal of photochemistry and photobiology. A, Chemistry399112612 Elsevier

Dye sensitized solar cells (DSSCs) were fabricated by using 2(3,5-biscarboxyphenoxy), 9(10), 16(17), 23(24)-tri(tertbutyl) phthalocyaninato Cu (4) and Zn (5) complexes as dyes on the ITO-TiO2 photoanodes containing reduced graphene oxide nanosheets (rGONS) or nitrogen-doped rGONS (NrGONS). The evaluation of the assembled DSSCs revealed that using ITO-TiO2-NrGONS-CuPc photoanode had the highest fill factor (FF) and power conversion efficiency (eta) of 69% and 4.36% respectively. These results show that the asymmetrical phthalocyanine complexes (4) and (5) exhibit significant improvement on the performance of the DSSC compared to our previous work on symmetrical carboxylated phthalocyanines with eta = 3.19%.

P. P. Mokoena, D. O. Oluwole, T. Nyokong, H. C. Swart, O. M. Ntwaeaborwa (2021)Enhanced upconversion emission of Er3+-Yb3+ co-doped Ba-5(PO4)(3)OH powder phosphor for application in photodynamic therapy, In: Sensors and actuators. A. Physical331113014 Elsevier

Er3+-Yb3+ co-doped Ba-5(PO4)(3)OH nanoparticle powder phosphors were successfully synthesized by urea combustion method. The resulting powder phosphors were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high resolution scanning electron microscopy (HRSEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL). XRD data confirmed crystallization of pure hexagonal phase of Ba-5(PO4)(3)OH and HRSEM images showed formation of ellipsoidal particles. XPS data combined with EDS analysis confirmed the materials composition that corresponds with identification of all the chemical elements constituting the materials. The in vitro dark cytotoxicity of the particles confirmed lack of cytocidal behaviour in the absence of light, but considerable photodynamic therapy (PDT) activity was observed upon illumination. Upon excitation using a 980 nm laser, multiple emission peaks in the green and red regions corresponding to the optical transitions of Er3+ ion were observed. Upon co-doping with Yb3+, upconverted red emission was detected and this was attributable to non-radiative energy transfer from Yb3+ to Er3+. The proposed mechanism of upconversion photoluminescence is discussed. (C) 2021 Elsevier B.V. All rights reserved.

OLUYINKA DAVID OLUWOLE, LUCY COLEMAN, William Buchanan, TAO CHEN, ROBERTO MARCELLO LA RAGIONE, LIAN XIANG LIU (2022)Antibiotics-Free Compounds for Chronic Wound Healing, In: Pharmaceutics14(5)1021 MDPI