Photodynamic antimicrobial chemotherapy against Staphylococcus aureus and Escherichia coli sensitized using indium (III) cationic porphyrins linked to core-shell magnetic nanoparticles
- Authors: Makola, Lekgowa Collen
- Date: 2021-04
- Subjects: Photochemotherapy , Photosensitizing compounds , Staphylococcus aureus , Escherichia coli , Indium , Porphyrins , Magnetic nanoparticles , Quaternize
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177225 , vital:42801
- Description: Photodynamic antimicrobial chemotherapy (PACT) is a well-known antimicrobial therapy technique used against multi-drug resistant pathogens. In this study, the syntheses, characterization, photophysicochemical properties, and the applications of symmetrically and asymmetrically substituted cationic indium (III) porphyrins linked to silver/copper ferrite core-shell (Ag/CuFe2O4) magnetic nanoparticles (MNPs) as potential photosensitizers for PACT are reported. The synthesized complexes include axially modified porphyrins quaternized through an axial ligand. All the asymmetrically substituted porphyrins were linked to the NPs via an ester bond and the symmetrically substituted porphyrins were linked (peripherally and /or axially) via self-assembly (Ag-S and/or Ag-N). The impact of axial modification, peripheral substituents, conjugation to the NPs, the number of positive charges, and the chain length of the alkyl halides quaternizing agents on PACT efficacy and photophysicochemical properties of porphyrins were studied. High singlet oxygen quantum yields and antimicrobial log reductions were observed. Lipophilicity and hydrophilicity of the porphyrins were also studies, where the complexes quaternized with methyl iodide showed relatively high hydrophilicity character. Upon in vitro PACT studies, the quaternized complexes were observed to have 0% viable colony, signifying their effectiveness. Moreover, the highest log reductions of 9.27 were observed against S. aureus and 9.58 were observed against E. coli. The findings from this work delineate that singlet oxygen generation alone is not a distinct factor on the PACT efficacy of the porphyrin complexes, since some of the complexes have practically the same singlet oxygen quantum but different PACT activity. However, other contributing factors including water solubility play a significant role. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Makola, Lekgowa Collen
- Date: 2021-04
- Subjects: Photochemotherapy , Photosensitizing compounds , Staphylococcus aureus , Escherichia coli , Indium , Porphyrins , Magnetic nanoparticles , Quaternize
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177225 , vital:42801
- Description: Photodynamic antimicrobial chemotherapy (PACT) is a well-known antimicrobial therapy technique used against multi-drug resistant pathogens. In this study, the syntheses, characterization, photophysicochemical properties, and the applications of symmetrically and asymmetrically substituted cationic indium (III) porphyrins linked to silver/copper ferrite core-shell (Ag/CuFe2O4) magnetic nanoparticles (MNPs) as potential photosensitizers for PACT are reported. The synthesized complexes include axially modified porphyrins quaternized through an axial ligand. All the asymmetrically substituted porphyrins were linked to the NPs via an ester bond and the symmetrically substituted porphyrins were linked (peripherally and /or axially) via self-assembly (Ag-S and/or Ag-N). The impact of axial modification, peripheral substituents, conjugation to the NPs, the number of positive charges, and the chain length of the alkyl halides quaternizing agents on PACT efficacy and photophysicochemical properties of porphyrins were studied. High singlet oxygen quantum yields and antimicrobial log reductions were observed. Lipophilicity and hydrophilicity of the porphyrins were also studies, where the complexes quaternized with methyl iodide showed relatively high hydrophilicity character. Upon in vitro PACT studies, the quaternized complexes were observed to have 0% viable colony, signifying their effectiveness. Moreover, the highest log reductions of 9.27 were observed against S. aureus and 9.58 were observed against E. coli. The findings from this work delineate that singlet oxygen generation alone is not a distinct factor on the PACT efficacy of the porphyrin complexes, since some of the complexes have practically the same singlet oxygen quantum but different PACT activity. However, other contributing factors including water solubility play a significant role. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
Synthesis, photophysicochemical properties and photodynamic therapy activities of indium and zinc phthalocyanines when incorporated into Pluronic polymer micelles
- Authors: Motloung, Banele Mike
- Date: 2020
- Subjects: Indium , Zinc , Phthalocyanines , Polymers , Photochemotherapy , Micelles
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167529 , vital:41489
- Description: This thesis reports on the syntheses, photophysicochemical properties and photodynamic therapy activities of symmetrical metallophthalocyanines (MPcs) when alone or when incorporated into Pluronic polymer micelles. The Pcs contain either zinc or indium as central metals and have phenyldiazenylphenoxy, pyridine-2-yloxy and benzo[d]thiazol-2-ylthio as ring substituents. Spectroscopic and microscopic techniques were used to confirm the formation MPcs with micelles. The photophysics and photochemistry of the Pcs were assessed when alone and with micelles. All the studied Pcs showed good photophysicochemical behavior with relatively high triplet and singlet oxygen quantum yields corresponding to their low fluorescence quantum yields. The Pcs with indium in their central cavity exhibited higher triplet and singlet oxygen quantum yields in comparison to their zinc counterparts due to the heavy atom effect obtained from the former. The in vitro dark cytotoxicity and photodynamic therapy of the Pc complexes and conjugates against MCF7 cells was tested. All studied Pc complexes alone and with micelles showed minimum dark toxicity making them applicable for PDT. All complexes displayed good phototoxicity < 50% cell viability (except for complex 2 > 50% cell viability) at concentrations ≤100 μg/mL, however the conjugates showed < 45% cell viability at concentrations ≤ 100 μg/mL, probably due to the small micellar size and EPR effect. The findings from this work show the importance of incorporating photosensitizers such as phthalocyanines into Pluronic polymers micelles and making them water soluble and ultimately improving their photodynamic effect.
- Full Text:
- Date Issued: 2020
- Authors: Motloung, Banele Mike
- Date: 2020
- Subjects: Indium , Zinc , Phthalocyanines , Polymers , Photochemotherapy , Micelles
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167529 , vital:41489
- Description: This thesis reports on the syntheses, photophysicochemical properties and photodynamic therapy activities of symmetrical metallophthalocyanines (MPcs) when alone or when incorporated into Pluronic polymer micelles. The Pcs contain either zinc or indium as central metals and have phenyldiazenylphenoxy, pyridine-2-yloxy and benzo[d]thiazol-2-ylthio as ring substituents. Spectroscopic and microscopic techniques were used to confirm the formation MPcs with micelles. The photophysics and photochemistry of the Pcs were assessed when alone and with micelles. All the studied Pcs showed good photophysicochemical behavior with relatively high triplet and singlet oxygen quantum yields corresponding to their low fluorescence quantum yields. The Pcs with indium in their central cavity exhibited higher triplet and singlet oxygen quantum yields in comparison to their zinc counterparts due to the heavy atom effect obtained from the former. The in vitro dark cytotoxicity and photodynamic therapy of the Pc complexes and conjugates against MCF7 cells was tested. All studied Pc complexes alone and with micelles showed minimum dark toxicity making them applicable for PDT. All complexes displayed good phototoxicity < 50% cell viability (except for complex 2 > 50% cell viability) at concentrations ≤100 μg/mL, however the conjugates showed < 45% cell viability at concentrations ≤ 100 μg/mL, probably due to the small micellar size and EPR effect. The findings from this work show the importance of incorporating photosensitizers such as phthalocyanines into Pluronic polymers micelles and making them water soluble and ultimately improving their photodynamic effect.
- Full Text:
- Date Issued: 2020
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