Physicochemical properties and photodynamic therapy activities of indium and zinc phthalocyanine-nanoparticle conjugates
- Authors: Dube, Edith
- Date: 2019
- Subjects: Indium , Zinc , Phthalocyanines , Breast -- Cancer -- Photochemotherapy , Nanoparticles
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76506 , vital:30589
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position are reported. The Pcs contain either zinc or indium as central metals and have carboxyphenoxy, phenoxy propanoic acid, benzothiazole phenoxy, thiophine ethoxy or di-O-isopropylidene-α-D-glucopyranose as ring substituents. The Pcs were linked to NPs via an amide bond or through self-assembly. The photophysics and photochemistry of the Pcs were assessed when alone and with conjugates. All the studied Pcs showed good photophysicochemical behaviour with relatively high triplet and singlet oxygen quantum yields corresponding to their low fluorescence quantum yield. 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. Asymmetrical Pcs displayed higher triplet and singlet oxygen quantum yields than their symmetrical counterparts. The triplet quantum yield, generally increased on linkage to nanoparticles (NPs) due to the heavy–atom effect of gold and silver in NPs. The conjugates to gold nanospheres yielded higher triplet and singlet quantum yields than their gold nanotriangles counterparts due to the higher loading by the former probably encouraged by their relatively small particle size. The in vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. All complexes displayed poor phototoxicity with >50Îll viability at concentrations≤ 160μg/mL, however the conjugates showed<50% cell viabilityatconcentrations≤ 160μg/mLprobably due to the enhanced singlet oxygen quantum yield. The findings from this work show the importance of linking photosensitises such as phthalocyanines to metal nanoparticles for the enhancement ofsinglet oxygen quantum yield and ultimately the photodynamic effect.
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- Date Issued: 2019
Photophysical studies of Zinc phthalocyanine-silica nanoparticles conjugates
- Authors: Fashina, Adedayo
- Date: 2015
- Subjects: Nanoparticles , Phthalocyanines , Zinc , Silica , Photochemistry , Adsorption
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4537 , http://hdl.handle.net/10962/d1017917
- Description: This thesis reports on the synthesis and characterization of both symmetrical and asymmetrical Zinc phthalocyanine complexes. The complexes contained groups such as carboxylic, amino and alkyne for covalent grafting to the surface of silica nanoparticles. The use of symmetrical and asymmetrical complexes was geared towards comparing the non-specific binding of the symmetrical complexes to the specific binding observed in the asymmetrical complexes. The complexes were also doped within the silica matrix and compared to the surface grafted conjugates. The complexes and the conjugates were well characterized with a variety of techniques. The fluorescence lifetimes of the phthalocyanine complexes containing either terminal carboxylic groups or an alkyne group showed a mono-exponential decay while the amino containing phthalocyanine complexes gave a bi-exponential decay. A similar trend was observed for their respective conjugates. Some of the conjugates of the asymmetrical complexes showed a decrease in fluorescence lifetimes and a corresponding decrease in fluorescence quantum yields. The fluorescence quantum yields for all the symmetrical complexes studied showed either an improvement or retained the luminescence of the grafted phthalocyanine complex. Most of the conjugates showed a faster intersystem crossing time in comparison to the complexes alone. The grafted or doped conjugates containing symmetrical phthalocyanine complexes with carboxyl groups showed improvements both in fluorescence and triplet quantum yields. All the conjugates except two showed an increase in triplet lifetimes when compared to their respective phthalocyanine complexes. Optical nonlinearities of nine of the phthalocyanine complexes were studied and all the complexes showed characteristic reverse saturable absorption behavior. Complex 10 showed the most promising optical limiting behavior. The aggregation and dissolution studies of the conjugates were also carried out in a simulated biological medium and the silicon level detected was noticed to have increased with incubation time.
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- Date Issued: 2015