Overcoming hurdles facing researchers in Africa
- Nyokong, Tebello, Ngoy, Bokolombe P, Amuhaya, Edith K
- Authors: Nyokong, Tebello , Ngoy, Bokolombe P , Amuhaya, Edith K
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177511 , vital:42828 , https://doi.org/10.1038/s41563-021-00961-0
- Description: Several countries on the African continent recognize that a transition to a knowledge-based economic model would stimulate growth and enable scientific independence. Investing in new knowledge would drive the formation of highly qualified professionals and the use of advanced technologies, triggering in return positive economic trends. Importantly, a knowledge-based economy that values the impact of science on society would help reversing the migration of skilled workers and lead to brain gain.
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- Authors: Nyokong, Tebello , Ngoy, Bokolombe P , Amuhaya, Edith K
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177511 , vital:42828 , https://doi.org/10.1038/s41563-021-00961-0
- Description: Several countries on the African continent recognize that a transition to a knowledge-based economic model would stimulate growth and enable scientific independence. Investing in new knowledge would drive the formation of highly qualified professionals and the use of advanced technologies, triggering in return positive economic trends. Importantly, a knowledge-based economy that values the impact of science on society would help reversing the migration of skilled workers and lead to brain gain.
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Photodynamic antimicrobial action of asymmetrical porphyrins functionalized silver-detonation nanodiamonds nanoplatforms for the suppression of Staphylococcus aureus planktonic cells and biofilms
- Openda, Yolande I, Ngoy, Bokolombe P, Nyokong, Tebello
- Authors: Openda, Yolande I , Ngoy, Bokolombe P , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190544 , vital:45004 , xlink:href="https://doi.org/10.3389/fchem.2021.628316"
- Description: New asymmetrical porphyrin derivatives containing a p-hydroxyphenyl moiety and p-acetylphenyl moieties along with their functionalized silver-detonation nanodiamonds nanohybrids were characterized and their photophysicochemical properties were established. The study provides evidence that the metalated porphyrin derivatives were red-shifted in absorption wavelength and possessed high singlet oxygen quantum yield comparative to the unmetalated core, thus making them suitable agents for photodynamic antimicrobial chemotherapy. As a result of conjugation to detonation nanodiamonds and silver nanoparticles, these compounds proved to be more effective as they exhibited stronger antibacterial and anti-biofilm activities on the multi-drug resistant S. aureus strain due to synergetic effect, compared to Ps alone. This suggests that the newly prepared nanohybrids could be used as a potential antimicrobial agent in the treatment of biofilms caused by S. aureus strain.
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- Authors: Openda, Yolande I , Ngoy, Bokolombe P , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190544 , vital:45004 , xlink:href="https://doi.org/10.3389/fchem.2021.628316"
- Description: New asymmetrical porphyrin derivatives containing a p-hydroxyphenyl moiety and p-acetylphenyl moieties along with their functionalized silver-detonation nanodiamonds nanohybrids were characterized and their photophysicochemical properties were established. The study provides evidence that the metalated porphyrin derivatives were red-shifted in absorption wavelength and possessed high singlet oxygen quantum yield comparative to the unmetalated core, thus making them suitable agents for photodynamic antimicrobial chemotherapy. As a result of conjugation to detonation nanodiamonds and silver nanoparticles, these compounds proved to be more effective as they exhibited stronger antibacterial and anti-biofilm activities on the multi-drug resistant S. aureus strain due to synergetic effect, compared to Ps alone. This suggests that the newly prepared nanohybrids could be used as a potential antimicrobial agent in the treatment of biofilms caused by S. aureus strain.
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Synthesis, theoretical calculations and laser flash photolysis studies of selected amphiphilic porphyrin derivatives used as biofilm photodegradative materials
- Openda, Yolande I, Ngoy, Bokolombe P, Muva, Jules T, Nyokong, Tebello
- Authors: Openda, Yolande I , Ngoy, Bokolombe P , Muva, Jules T , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190589 , vital:45008 , xlink:href="https://doi.org/10.1039/D1NJ02651H"
- Description: Photodynamic antimicrobial activities of gallium and indium porphyrins as well as their quaternized derivatives have been investigated against S. aureus and E. coli biofilms, as well as on their planktonic (free floating) cells using a light emitting diode lamp at 415 nm. The studied photosensitizers show considerable ability to generate singlet oxygen and the quaternized molecules 2a and 3a are potential photodynamic antimicrobial chemotherapy (PACT) agents with log10 colony forming units >9 for E. coli and S. aureus planktonic cells. The quaternized derivatives are found to have higher ability to significantly suppress the biofilms of both S. aureus and E. coli in vitro. Therefore, this demonstrates that they are potentially suitable photosensitive agents for PACT use. The TD-B3LYP/LanL2DZ calculations were performed to evaluate the singlet excitation energies of quaternized and non-quaternized porphyrins in vacuo. Our study shows excellent agreement between time-dependent density-functional theory (TD-DFT) excited energies and experimental S1 > S0 excitation energies. The small deviation observed between the calculated and experimental spectra arises from the solvent effect. The excitation energies observed in these UV-visible spectra mostly originated from electron promotion between the highest occupied molecular orbital (HOMO) for the less intense band and the HOMO−1 for the most intense band of the ground states to the lower unoccupied molecular orbital (LUMO) of the excited states.
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- Authors: Openda, Yolande I , Ngoy, Bokolombe P , Muva, Jules T , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190589 , vital:45008 , xlink:href="https://doi.org/10.1039/D1NJ02651H"
- Description: Photodynamic antimicrobial activities of gallium and indium porphyrins as well as their quaternized derivatives have been investigated against S. aureus and E. coli biofilms, as well as on their planktonic (free floating) cells using a light emitting diode lamp at 415 nm. The studied photosensitizers show considerable ability to generate singlet oxygen and the quaternized molecules 2a and 3a are potential photodynamic antimicrobial chemotherapy (PACT) agents with log10 colony forming units >9 for E. coli and S. aureus planktonic cells. The quaternized derivatives are found to have higher ability to significantly suppress the biofilms of both S. aureus and E. coli in vitro. Therefore, this demonstrates that they are potentially suitable photosensitive agents for PACT use. The TD-B3LYP/LanL2DZ calculations were performed to evaluate the singlet excitation energies of quaternized and non-quaternized porphyrins in vacuo. Our study shows excellent agreement between time-dependent density-functional theory (TD-DFT) excited energies and experimental S1 > S0 excitation energies. The small deviation observed between the calculated and experimental spectra arises from the solvent effect. The excitation energies observed in these UV-visible spectra mostly originated from electron promotion between the highest occupied molecular orbital (HOMO) for the less intense band and the HOMO−1 for the most intense band of the ground states to the lower unoccupied molecular orbital (LUMO) of the excited states.
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