Characterization of phthalocyanine functionalized quantum dots by dynamic light scattering, laser Doppler, and capillary electrophoresis
- Ramírez-García, Gonzalo, Oluwole, David O, Nxele, Siphesihle Robin, d’Orlyé, Fanny, Nyokong, Tebello, Bedioui, Fethi, Varenne, Anne
- Authors: Ramírez-García, Gonzalo , Oluwole, David O , Nxele, Siphesihle Robin , d’Orlyé, Fanny , Nyokong, Tebello , Bedioui, Fethi , Varenne, Anne
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/238184 , vital:50595 , xlink:href="https://doi.org/10.1007/s00216-016-0120-x"
- Description: In this work, we characterized different phtalocyanine-capped core/shell/shell quantum dots (QDs) in terms of stability, ζ-potential, and size at various pH and ionic strengths, by means of capillary electrophoresis (CE), and compared these results to the ones obtained by laser Doppler electrophoresis (LDE) and dynamic light scattering (DLS). The effect of the phthalocyanine metallic center (Zn, Al, or In), the number (one or four), and nature of substituents (carboxyphenoxy- or sulfonated-) of functionalization on the phthalocyanine physicochemical properties were evaluated. Whereas QDs capped with zinc mono-carboxyphenoxy-phtalocyanine (ZnMCPPc-QDs) remained aggregated in the whole analyzed pH range, even at low ionic strength, QDs capped with zinc tetracarboxyphenoxy phtalocyanine (ZnTPPc-QDs) were easily dispersed in buffers at pH equal to or higher than 7.4. QDs capped with aluminum tetrasulfonated phthalocyanine (AlTSPPc-QDs) and indium tetracarboxyphenoxy phthalocyanines (InTCPPc-QDs) were stable in aqueous suspension only at pH higher than 9.0 due to the presence of functional groups bound to the metallic center of the phthalocyanine. The ζ-potential values determined by CE for all the samples decreased when ionic strength increased, being well correlated with the aggregation of the nanoconjugates at elevated salt concentrations. The use of electrokinetic methodologies has provided insights into the colloidal stability of the photosensitizer-functionalized QDs in physiological relevant solutions and thereby, its usefulness for improving their design and applications for photodynamic therapy.
- Full Text:
- Date Issued: 2017
- Authors: Ramírez-García, Gonzalo , Oluwole, David O , Nxele, Siphesihle Robin , d’Orlyé, Fanny , Nyokong, Tebello , Bedioui, Fethi , Varenne, Anne
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/238184 , vital:50595 , xlink:href="https://doi.org/10.1007/s00216-016-0120-x"
- Description: In this work, we characterized different phtalocyanine-capped core/shell/shell quantum dots (QDs) in terms of stability, ζ-potential, and size at various pH and ionic strengths, by means of capillary electrophoresis (CE), and compared these results to the ones obtained by laser Doppler electrophoresis (LDE) and dynamic light scattering (DLS). The effect of the phthalocyanine metallic center (Zn, Al, or In), the number (one or four), and nature of substituents (carboxyphenoxy- or sulfonated-) of functionalization on the phthalocyanine physicochemical properties were evaluated. Whereas QDs capped with zinc mono-carboxyphenoxy-phtalocyanine (ZnMCPPc-QDs) remained aggregated in the whole analyzed pH range, even at low ionic strength, QDs capped with zinc tetracarboxyphenoxy phtalocyanine (ZnTPPc-QDs) were easily dispersed in buffers at pH equal to or higher than 7.4. QDs capped with aluminum tetrasulfonated phthalocyanine (AlTSPPc-QDs) and indium tetracarboxyphenoxy phthalocyanines (InTCPPc-QDs) were stable in aqueous suspension only at pH higher than 9.0 due to the presence of functional groups bound to the metallic center of the phthalocyanine. The ζ-potential values determined by CE for all the samples decreased when ionic strength increased, being well correlated with the aggregation of the nanoconjugates at elevated salt concentrations. The use of electrokinetic methodologies has provided insights into the colloidal stability of the photosensitizer-functionalized QDs in physiological relevant solutions and thereby, its usefulness for improving their design and applications for photodynamic therapy.
- Full Text:
- Date Issued: 2017
Surface patterning using scanning electrochemical microscopy to locally trigger a “click” chemistry reaction
- Quinton, Damien, Maringa, Audacity, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Quinton, Damien , Maringa, Audacity , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Language: English
- Type: Article
- Identifier: vital:7331 , http://hdl.handle.net/10962/d1020592
- Description: We report on the surface micropatterning of conductive surfaces via the electrochemical triggering of a click reaction, the copper(I) catalyzed azide–alkyne cycloaddition reaction (CuAAC) by SECM via a two-step approach: (i) functionalization on the entire surface with azido-aryl groups by using the diazonium approach followed by (ii) the covalent linkage of alkyne-bearing ferrocene by CuAAC within a local area by SECM. More precisely, the click reaction was triggered by Cu(I) catalyst generation for 30 min at the SECM tip positioned ≈ 10 μm above the azido-aryl modified surface. The dimension of the spot obtained under these conditions was ≈ 75 μm. The electrochemical imaging by SECM of the ultra thin area locally clicked with ferrocene moieties was made thanks to the electrocatalytic properties of the ferrocene modified surface towards ferrocyanide electrooxidation. This local clicking procedure opens the gate to further controlled functionalization of restricted small substrates. , Original publication is available at http://dx.doi.org/10.1016/j.elecom.2013.03.021
- Full Text: false
- Authors: Quinton, Damien , Maringa, Audacity , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Language: English
- Type: Article
- Identifier: vital:7331 , http://hdl.handle.net/10962/d1020592
- Description: We report on the surface micropatterning of conductive surfaces via the electrochemical triggering of a click reaction, the copper(I) catalyzed azide–alkyne cycloaddition reaction (CuAAC) by SECM via a two-step approach: (i) functionalization on the entire surface with azido-aryl groups by using the diazonium approach followed by (ii) the covalent linkage of alkyne-bearing ferrocene by CuAAC within a local area by SECM. More precisely, the click reaction was triggered by Cu(I) catalyst generation for 30 min at the SECM tip positioned ≈ 10 μm above the azido-aryl modified surface. The dimension of the spot obtained under these conditions was ≈ 75 μm. The electrochemical imaging by SECM of the ultra thin area locally clicked with ferrocene moieties was made thanks to the electrocatalytic properties of the ferrocene modified surface towards ferrocyanide electrooxidation. This local clicking procedure opens the gate to further controlled functionalization of restricted small substrates. , Original publication is available at http://dx.doi.org/10.1016/j.elecom.2013.03.021
- Full Text: false