Photophysicochemical properties of nanoconjugates of zinc (II) 2 (3)-mono-2-(4-oxy) phenoxy) acetic acid phthalocyanine with cysteamine capped silver and silver–gold nanoparticles
- Oluwole, David O, Prinsloo, Earl, Nyokong, Tebello
- Authors: Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188552 , vital:44764 , xlink:href="https://doi.org/10.1016/j.poly.2016.09.034"
- Description: A novel asymmetrical zinc(II) 2(3)-mono-2-(4-oxy)phenoxy)acetic acid phthalocyanine (complex 1) was synthesized and subsequently linked to cysteamine capped silver (AgNPs) and silver–gold (AgAuNPs) nanoparticles (NPs) via amide bonds. The photophysicochemical properties and in vitro photodynamic therapy activity of complex 1 and its nanoconjugates were investigated. The nanoconjugates showed improved photophysical properties compared to complex 1 alone. The fluorescence, triplet and singlet quantum yields of complex 1 were found to be 20%, 48%, and 43% respectively. Complex 1 showed in vitro dark cytotoxicity, but the dark toxicity was reduced for the combination of complex 1 with AgAuNPs, this combination also gave the best photodynamic therapy activity when compared to complex 1 and its conjugate with AgNPs without AuNPs.
- Full Text:
- Date Issued: 2016
- Authors: Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188552 , vital:44764 , xlink:href="https://doi.org/10.1016/j.poly.2016.09.034"
- Description: A novel asymmetrical zinc(II) 2(3)-mono-2-(4-oxy)phenoxy)acetic acid phthalocyanine (complex 1) was synthesized and subsequently linked to cysteamine capped silver (AgNPs) and silver–gold (AgAuNPs) nanoparticles (NPs) via amide bonds. The photophysicochemical properties and in vitro photodynamic therapy activity of complex 1 and its nanoconjugates were investigated. The nanoconjugates showed improved photophysical properties compared to complex 1 alone. The fluorescence, triplet and singlet quantum yields of complex 1 were found to be 20%, 48%, and 43% respectively. Complex 1 showed in vitro dark cytotoxicity, but the dark toxicity was reduced for the combination of complex 1 with AgAuNPs, this combination also gave the best photodynamic therapy activity when compared to complex 1 and its conjugate with AgNPs without AuNPs.
- Full Text:
- Date Issued: 2016
The effect of point of substitution and silver based nanoparticles on the photophysical and optical nonlinearity of indium carboxyphenoxy phthalocyanine
- Oluwole, David O, Ngxeke, Sixolisile M, Britton, Jonathan, Nyokong, Tebello
- Authors: Oluwole, David O , Ngxeke, Sixolisile M , Britton, Jonathan , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188596 , vital:44768 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.07.032"
- Description: Indium(III) chloride 1,8(11),15(18),22(25)-tetra-(3-carboxyphenoxy) phthalocyanine (1) and indium(III) chloride 2,9(10),16(17),23(24)-tetra–(3-carboxyphenoxy) phthalocyanine (2) were covalently linked to glutathione capped silver nanoparticles (AgNPs–GSH) and silver selenide/zinc sulfide (Ag2Se/ZnS–GSH) quantum dots via amide bond formation. The photophysical and nonlinear optical behaviour of the metallophthalocyanines and their conjugates with nanoparticles were investigated using the open aperture Z–scan technique. Complex 2 showed enhanced photophysical properties compared to 1. The conjugates revealed improved triplet state quantum yields (except for 1-AgNPs-GSH which afforded lower triplet state quantum yields in comparison to 1) and nonlinear optical activities in comparison to the Pc complexes. The synthesized complexes, nanoparticles and their conjugates could be potential nonlinear optical materials due to their good nonlinear optical activities.
- Full Text:
- Date Issued: 2017
- Authors: Oluwole, David O , Ngxeke, Sixolisile M , Britton, Jonathan , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188596 , vital:44768 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.07.032"
- Description: Indium(III) chloride 1,8(11),15(18),22(25)-tetra-(3-carboxyphenoxy) phthalocyanine (1) and indium(III) chloride 2,9(10),16(17),23(24)-tetra–(3-carboxyphenoxy) phthalocyanine (2) were covalently linked to glutathione capped silver nanoparticles (AgNPs–GSH) and silver selenide/zinc sulfide (Ag2Se/ZnS–GSH) quantum dots via amide bond formation. The photophysical and nonlinear optical behaviour of the metallophthalocyanines and their conjugates with nanoparticles were investigated using the open aperture Z–scan technique. Complex 2 showed enhanced photophysical properties compared to 1. The conjugates revealed improved triplet state quantum yields (except for 1-AgNPs-GSH which afforded lower triplet state quantum yields in comparison to 1) and nonlinear optical activities in comparison to the Pc complexes. The synthesized complexes, nanoparticles and their conjugates could be potential nonlinear optical materials due to their good nonlinear optical activities.
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- Date Issued: 2017
Photophysicochemical properties and photodynamic therapy activity of highly water-soluble Zn (II) phthalocyanines
- Oluwole, David O, Sari, Fatma Aslihan, Prinsloo, Earl, Dube, Edith, Yuzer, Abdulcelil, Nyokong, Tebello, Ince, Mine
- Authors: Oluwole, David O , Sari, Fatma Aslihan , Prinsloo, Earl , Dube, Edith , Yuzer, Abdulcelil , Nyokong, Tebello , Ince, Mine
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234507 , vital:50203 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.090"
- Description: The syntheses of two zinc(II) phthalocyanines (ZnPcs) having either imidazole (ZnPc 1) or pyridiloxy (ZnPc 2) moieties as their macrocycle substituents are reported. Quaternization of the ZnPcs with methyl iodide afforded water soluble cationic phthalocyanines. The photophysical, photochemical properties and photodynamic therapy (PDT) activity of the ZnPcs were studied in solution. The fluorescence quantum yield and lifetime of ZnPc 1 were higher as compared to ZnPc 2. ZnPc 2 afforded higher triplet state (ΦT) and singlet oxygen quantum yields (ΦΔ) in comparison to ZnPc 1. The PDT activity of ZnPcs was investigated against human breast adenocarcinoma cells (MCF–7). The two compounds afforded a very minimal in vitro dark cytotoxicity with 85% viable cells at concentration ≤80 μM. On irradiation of the cells having the ZnPcs, ≥50% cell death was recorded for ZnPc 1 which was also evidenced by the cells photo–micrograph.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Sari, Fatma Aslihan , Prinsloo, Earl , Dube, Edith , Yuzer, Abdulcelil , Nyokong, Tebello , Ince, Mine
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234507 , vital:50203 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.090"
- Description: The syntheses of two zinc(II) phthalocyanines (ZnPcs) having either imidazole (ZnPc 1) or pyridiloxy (ZnPc 2) moieties as their macrocycle substituents are reported. Quaternization of the ZnPcs with methyl iodide afforded water soluble cationic phthalocyanines. The photophysical, photochemical properties and photodynamic therapy (PDT) activity of the ZnPcs were studied in solution. The fluorescence quantum yield and lifetime of ZnPc 1 were higher as compared to ZnPc 2. ZnPc 2 afforded higher triplet state (ΦT) and singlet oxygen quantum yields (ΦΔ) in comparison to ZnPc 1. The PDT activity of ZnPcs was investigated against human breast adenocarcinoma cells (MCF–7). The two compounds afforded a very minimal in vitro dark cytotoxicity with 85% viable cells at concentration ≤80 μM. On irradiation of the cells having the ZnPcs, ≥50% cell death was recorded for ZnPc 1 which was also evidenced by the cells photo–micrograph.
- Full Text:
- Date Issued: 2018
The effects of silica based nanoparticles on the photophysicochemical properties, in vitro dark viability and photodynamic therapy study of zinc monocarboxyphenoxy phthalocyanine
- Oluwole, David O, Uddin, Imran, Prinsloo, Earl, Nyokong, Tebello
- Authors: Oluwole, David O , Uddin, Imran , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240371 , vital:50828 , xlink:href="https://doi.org/10.1016/j.jphotochem.2016.07.002"
- Description: Aminopropyl triethoxysilane functionalized core SiO2 and core/shell ZnO/SiO2 nanoparticles (NP) were covalently linked to zinc monocarboxyphenoxy phthalocyanine (ZnMCPPc, complex 1) via amide bond formation. The photophysicochemical behavior, in vitro dark viability and photodynamic therapy (PDT) activity against human breast adenocarcinoma cell line (MCF-7 cells) of the conjugates were studied. The nanoconjugates showed enhanced photophysicochemical behavior as compared to complex 1 alone. Complex 1 showed higher dark toxicity against MCF-7 cells when compared to the conjugates. In the dark, complex 1 accounted for less than 50% viable cells at 28.6 μg/mL and 57.1 μg/mL compared to the conjugates which accounted for more than 50% cell viability at these concentrations. The in vitro dark viability and PDT activity of complex 1 was reduced in the presence of these nanoparticles.
- Full Text:
- Date Issued: 2016
- Authors: Oluwole, David O , Uddin, Imran , Prinsloo, Earl , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240371 , vital:50828 , xlink:href="https://doi.org/10.1016/j.jphotochem.2016.07.002"
- Description: Aminopropyl triethoxysilane functionalized core SiO2 and core/shell ZnO/SiO2 nanoparticles (NP) were covalently linked to zinc monocarboxyphenoxy phthalocyanine (ZnMCPPc, complex 1) via amide bond formation. The photophysicochemical behavior, in vitro dark viability and photodynamic therapy (PDT) activity against human breast adenocarcinoma cell line (MCF-7 cells) of the conjugates were studied. The nanoconjugates showed enhanced photophysicochemical behavior as compared to complex 1 alone. Complex 1 showed higher dark toxicity against MCF-7 cells when compared to the conjugates. In the dark, complex 1 accounted for less than 50% viable cells at 28.6 μg/mL and 57.1 μg/mL compared to the conjugates which accounted for more than 50% cell viability at these concentrations. The in vitro dark viability and PDT activity of complex 1 was reduced in the presence of these nanoparticles.
- Full Text:
- Date Issued: 2016
Optical nonlinearity of pentadecylphenoxyl substituted sandwich–type metallophthalocyanines in the presence of Ag–CdSeTe/ZnTeSe nanocrystals: Effects of conjugation and central metals
- Oluwole, David O, Nyokong, Tebello
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187899 , vital:44708 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.01.009"
- Description: Novel pentadecylphenoxyl substituted homoleptic sandwich–type metallophthalocyanines: bis (complexes 2 and 4 containing Eu and Dy, respectively) and tris (complexes 3 and 5 containing Eu and Dy, respectively) 2,9,16,23–tetrakis–(3–pentadecylphenoxyl) phthalocyanines and cadmium based (Ag–CdSeTe/ZnTeSe) nanocrystals (NCs) were synthesized. The nonlinear optical (NLO) behavior of the metallophthalocyanines and their composites with NCs were investigated using the open aperture Z–scan technique at excitation wavelength of 532 nm with 10 ns pulse. All of the samples exhibited interesting NLO attributes: among all the sandwich–type complexes, complex 5 afforded the most efficient NLO features accounting for large nonlinear absorption coefficient (βeff) value of 3500 cm/GW and limiting threshold (Ilim) value of 0.43 J cm−2. Overall, the composites of the triple decker sandwich–type complexes with Ag–CdSeTe/ZnTeSe yielded the best NLO characteristics with 3 and 5 accounting for the largest βeff value of 5500 cm/GW and Ilim value of 0.09 J cm−2. The synthesized complexes and their composites with NCs could be viable and efficient NLO absorber due to their interesting NLO activities.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187899 , vital:44708 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.01.009"
- Description: Novel pentadecylphenoxyl substituted homoleptic sandwich–type metallophthalocyanines: bis (complexes 2 and 4 containing Eu and Dy, respectively) and tris (complexes 3 and 5 containing Eu and Dy, respectively) 2,9,16,23–tetrakis–(3–pentadecylphenoxyl) phthalocyanines and cadmium based (Ag–CdSeTe/ZnTeSe) nanocrystals (NCs) were synthesized. The nonlinear optical (NLO) behavior of the metallophthalocyanines and their composites with NCs were investigated using the open aperture Z–scan technique at excitation wavelength of 532 nm with 10 ns pulse. All of the samples exhibited interesting NLO attributes: among all the sandwich–type complexes, complex 5 afforded the most efficient NLO features accounting for large nonlinear absorption coefficient (βeff) value of 3500 cm/GW and limiting threshold (Ilim) value of 0.43 J cm−2. Overall, the composites of the triple decker sandwich–type complexes with Ag–CdSeTe/ZnTeSe yielded the best NLO characteristics with 3 and 5 accounting for the largest βeff value of 5500 cm/GW and Ilim value of 0.09 J cm−2. The synthesized complexes and their composites with NCs could be viable and efficient NLO absorber due to their interesting NLO activities.
- Full Text:
- Date Issued: 2018
Photophysicochemical behaviour of metallophthalocyanines when doped onto silica nanoparticles
- Oluwole, David O, Nyokong, Tebello
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188518 , vital:44761 , xlink:href="https://doi.org/10.1016/j.dyepig.2016.08.053"
- Description: Aluminum(III) chloride 2,9(10),16(17),23(24)–tetra–(4–tert–butylphenoxy)phthalocyanine (1), zinc(II) 2,9(10),16(17),23(24)–tetra–(4–tert–butylphenoxy)phthalocyanine (2), zinc(II) 1,8(11),15(18),22(25)–tetra–(4–tert–butylphenoxy) phthalocyanine (3) and zinc(II) 2,9(10),16(17),23(24)–tetra–(4–carboxylphenoxy) phthalocyanine (4) were doped onto silica nanoparticles (SiNPs). There were no significant changes in fluorescence quantum yields and lifetimes of the metallophthalocyanines ( MPcs) when doped onto SiNPs. The triplet quantum yields of the MPcs alone range from 0.22 to 0.85 and in the presence of SiNPs the values range from 0.17 to 0.89. We observed a general decrease of triplet quantum yields of phthalocyanines in the conjugates except for 2 where there was an increase. The values were highly affected by aggregation. Complexes 1 and 3 were highly aggregated when doped onto SiNPs, while 2 and 4 did not show much aggregation.
- Full Text:
- Date Issued: 2017
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188518 , vital:44761 , xlink:href="https://doi.org/10.1016/j.dyepig.2016.08.053"
- Description: Aluminum(III) chloride 2,9(10),16(17),23(24)–tetra–(4–tert–butylphenoxy)phthalocyanine (1), zinc(II) 2,9(10),16(17),23(24)–tetra–(4–tert–butylphenoxy)phthalocyanine (2), zinc(II) 1,8(11),15(18),22(25)–tetra–(4–tert–butylphenoxy) phthalocyanine (3) and zinc(II) 2,9(10),16(17),23(24)–tetra–(4–carboxylphenoxy) phthalocyanine (4) were doped onto silica nanoparticles (SiNPs). There were no significant changes in fluorescence quantum yields and lifetimes of the metallophthalocyanines ( MPcs) when doped onto SiNPs. The triplet quantum yields of the MPcs alone range from 0.22 to 0.85 and in the presence of SiNPs the values range from 0.17 to 0.89. We observed a general decrease of triplet quantum yields of phthalocyanines in the conjugates except for 2 where there was an increase. The values were highly affected by aggregation. Complexes 1 and 3 were highly aggregated when doped onto SiNPs, while 2 and 4 did not show much aggregation.
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- Date Issued: 2017
Evaluation of the photophysicochemical properties and photodynamic therapy activity of nanoconjugates of zinc phthalocyanine linked to glutathione capped Au and Au3Ag1 nanoparticles
- Oluwole, David O, Manoto, Sello L, Malabi, Rudzani, Maphanga, Charles, Ombinda-Lemboumba, Saturnin, Mthunzi-Kufa, Patience, Nyokong, Tebello
- Authors: Oluwole, David O , Manoto, Sello L , Malabi, Rudzani , Maphanga, Charles , Ombinda-Lemboumba, Saturnin , Mthunzi-Kufa, Patience , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237886 , vital:50563 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.11.019"
- Description: We report on the synthesis of glutathione capped gold (AuNPs–GSH) and gold–silver (Au3Ag1NPs–GSH) nanoparticles and their covalent attachment to Zn monocarboxyphenoxy phthalocyanine (1) via amide bond formation. The photophysicochemical properties and photodynamic therapy (PDT) activity of the complex and its nanoconjugates were assessed. The conjugates afforded improved triplet and singlet oxygen quantum yield as well as PDT activity (except for 1-Au3Ag1NPs which afforded decreased activity) in comparison to complex 1.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Manoto, Sello L , Malabi, Rudzani , Maphanga, Charles , Ombinda-Lemboumba, Saturnin , Mthunzi-Kufa, Patience , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237886 , vital:50563 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.11.019"
- Description: We report on the synthesis of glutathione capped gold (AuNPs–GSH) and gold–silver (Au3Ag1NPs–GSH) nanoparticles and their covalent attachment to Zn monocarboxyphenoxy phthalocyanine (1) via amide bond formation. The photophysicochemical properties and photodynamic therapy (PDT) activity of the complex and its nanoconjugates were assessed. The conjugates afforded improved triplet and singlet oxygen quantum yield as well as PDT activity (except for 1-Au3Ag1NPs which afforded decreased activity) in comparison to complex 1.
- Full Text:
- Date Issued: 2018