Olga Bochkova - Academia.edu (original) (raw)
Papers by Olga Bochkova
Journal of Colloid and Interface Science, Feb 1, 2011
The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied i... more The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied in Triton X-100 (TX-100) solutions at various concentration conditions by fluorimetry, dynamic light scattering, electrophoresis and transmission electron microscopy methods. The temperature responsive behavior of nanoparticles is observed at definite concentration of TX-100, where the aggregation of TX-100 at the silica/water interface is evident from the increased size of the silica nanoparticles. The reversible dehydration of TX-100 aggregates at the silica/water interface should be assumed as the main reason of the temperature induced phase separation of silica nanoparticles. The distribution of nanoparticles between aqueous and surfactant rich phases at the phase separation conditions can be modified by the effect of additives.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015
LAT 2010: International Conference on Lasers, Applications, and Technologies, 2010
Positively charged luminescent silica nanoparticles loaded with Tb(III) complex were prepaired by... more Positively charged luminescent silica nanoparticles loaded with Tb(III) complex were prepaired by reverse microemulsion procedure with further modification by gemini surfactant. The xi-potential values and dynamic light scattering data indicate high positive charge and colloidal stability of the as prepaired nanoparticles. The high affinity of these nanoparticles to anions is verified by spectrophotometric measurements with dye molecules, namely phenol red.
The Journal of Physical Chemistry C, 2010
Novel silica nanoparticles exhibiting near-infrared (NIR) and dual NIR-visible emission were synt... more Novel silica nanoparticles exhibiting near-infrared (NIR) and dual NIR-visible emission were synthesized according to reverse microemulsion procedure through the encapsulation of Yb(III) complex with p-sulfonatothiacalix[4]arene (Yb) and [Ru(dipy) 3 ]Cl 2 (Ru) as NIR-and visible-emitting luminophores into silica matrix. The synthesis was carried out at various Yb:Ru molar ratio. The numbers of Ru and Yb complexes per one nanoparticle were calculated from both fluorimetric and inductively coupled plasma atomic emission spectroscopy data. The dynamic light scattering measurements of aqueous dispersions of Yb, Ru, and Ru-Yb nanoparticles elucidate the relationship between the complexes inserted into nanoparticles and their aqueous dispersity. The transmission electron microscopy images were used to measure the size of the nanoparticles. The atomic force microscopy images reveal the different aggregation morphology of Yb-and Ru-doped nanoparticles.
Talanta, 2012
The work represents colloids of silica nanoparticles displaying fluorescent response on bioreleva... more The work represents colloids of silica nanoparticles displaying fluorescent response on biorelevant compounds exemplified by phosphacoumarins and phospholipids. The luminescent properties of the colloids arise from Tb(III) complexes doped into silica nanoparticles (SNs). The noncovalent decoration of SNs by dicationic surfactant with further interfacial binding of dye anions enables to develop colloids programmed to display a substrate induced fluorescent response. The latter results from the quenching of Tb(III) centered luminescence by dye anions through dynamic mechanism and subsequent displacement of quenching anions by the non-quenching substrates from the interface of SNs. Both negative charge and hydrophobicity of substrates are the key factors affecting the selectivity of the substrate induced fluorescent response. The peculiar effects of zwitter-ionic and anionic phospholipids on the fluorescent response have been revealed. The applicability of the fluorescent procedure in the sensing of impurities in commercial phosphatidylcholine is also introduced.
Langmuir, 2009
Novel silica-coated Tb(III) nanoparticles with high luminecsence were synthesized using the rever... more Novel silica-coated Tb(III) nanoparticles with high luminecsence were synthesized using the reverse microemulsion procedure. The quenching of luminescent properties of these nanoparticles can be achieved by ion exchange and energy transfer mechanisms. The quenching through the ion exchange of Tb(III) by H + or La(III) is time dependent, indicating that the ion exchange is probably diffusion controlled. The quenching by Co(III) complex cations is achieved by the energy transfer mechanism and thus is not time dependent. The analysis of quenching data in Stern-Volmer cooordinates reveal the negative charge of the silica-coated Tb(III)-TCAS nanoparticles and several types of luminophoric species, located within the core and close to the surface of silica nanoparticles.
Journal of Physics: Conference Series, 2011
Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR ... more Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR luminescence (Ru-Yb doped) were obtained by reverse w/o microemulsion procedure. Plenty of luminescent complexes (from 4900 to 10000) encapsulated into each nanoparticle ensures the intensive luminescence of nanoparticles and their applicability as biomarkers. The silica surface decoration by definite anchor groups is the required
Journal of Colloid and Interface Science, 2011
The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied i... more The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied in Triton X-100 (TX-100) solutions at various concentration conditions by fluorimetry, dynamic light scattering, electrophoresis and transmission electron microscopy methods. The temperature responsive behavior of nanoparticles is observed at definite concentration of TX-100, where the aggregation of TX-100 at the silica/water interface is evident from the increased size of the silica nanoparticles. The reversible dehydration of TX-100 aggregates at the silica/water interface should be assumed as the main reason of the temperature induced phase separation of silica nanoparticles. The distribution of nanoparticles between aqueous and surfactant rich phases at the phase separation conditions can be modified by the effect of additives.
Colloids and Surfaces B: Biointerfaces, 2012
The quenching effect of dyes (phenol red and bromothymol blue) on Tb(III)-centered luminescence e... more The quenching effect of dyes (phenol red and bromothymol blue) on Tb(III)-centered luminescence enables to sense the aggregation of cationic and anionic surfactants near the silica surface of Tb-doped silica nanoparticles (SN) in aqueous solutions. The Tb-centered luminescence of non-decorated SNs is diminished by the inner filter effect of both dyes. The decoration of the silica surface by cationic surfactants induces the quenching through the energy transfer between silica coated Tb(III) complexes and dye anions inserted into surfactant aggregates. Thus the distribution of surfactants aggregates at the silica/water interface and in the bulk of solution greatly affects dynamic quenching efficiency. The displacement of dye anions from the interfacial surfactant adlayer by anionic surfactants and phospholipids is accompanied by the "off-on" switching of Tb(III)-centered luminescence.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011
The present work introduces the interaction of hard and soft colloids in aqueous solutions at var... more The present work introduces the interaction of hard and soft colloids in aqueous solutions at various temperatures and concentrations, as well as at critical conditions of temperature induced phase separation. Hard and soft colloids are represented by luminescent silica nanoparticles and aggregates of PEO-PPO-PEO and PPO-PEO-PPO triblock copolymers correspondingly. The formation of the mixed aggregates between hard and soft colloids in equilibrium conditions has been revealed by dynamic light scattering measurements. The distribution of silica nanoparticles between aqueous and surfactant rich phases after phase separation highlights the effect of pH, architecture and concentration of triblock copolymers on the mixed hard-soft colloids aggregation at cloud point conditions. The peculiar aggregation and phase behavior of PPO-PEO-PPO pluronics should be assumed as the main reason of the enhanced mixed aggregation with SNs at increased temperatures and concentrated conditions.
![Research paper thumbnail of Reactions of heteroaromatic chromophores with lanthanide complexes of p-sulfonatothiacalix[4]arene](https://attachments.academia-assets.com/43573722/thumbnails/1.jpg)
](Russian Chemical Bulletin, 2008
The conditions for the formation of heteroleptic complexes of a lanthanide(III) ion (Ln = La, Gd,... more The conditions for the formation of heteroleptic complexes of a lanthanide(III) ion (Ln = La, Gd, and Tb) with p sulfonatothiacalix[4]arene and a heteroaromatic chromophore in water were found using X ray diffraction analysis, pH metry, 1 H NMR and UV-Vis spectros copy, and nuclear magnetic relaxation. In the resulting complexes, the heteroaromatic chro mophore is in the calix[4]arene cavity and the lanthanide ion is coordinated by the electron donating groups of the upper or lower calix[4]arene rim. Emission spectroscopic studies re vealed changed emission properties of Tb III ions in the terbium(III)-p sulfonatothia calix[4]arene-bipy complex.
Journal of Colloid and Interface Science, Feb 1, 2011
The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied i... more The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied in Triton X-100 (TX-100) solutions at various concentration conditions by fluorimetry, dynamic light scattering, electrophoresis and transmission electron microscopy methods. The temperature responsive behavior of nanoparticles is observed at definite concentration of TX-100, where the aggregation of TX-100 at the silica/water interface is evident from the increased size of the silica nanoparticles. The reversible dehydration of TX-100 aggregates at the silica/water interface should be assumed as the main reason of the temperature induced phase separation of silica nanoparticles. The distribution of nanoparticles between aqueous and surfactant rich phases at the phase separation conditions can be modified by the effect of additives.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015
LAT 2010: International Conference on Lasers, Applications, and Technologies, 2010
Positively charged luminescent silica nanoparticles loaded with Tb(III) complex were prepaired by... more Positively charged luminescent silica nanoparticles loaded with Tb(III) complex were prepaired by reverse microemulsion procedure with further modification by gemini surfactant. The xi-potential values and dynamic light scattering data indicate high positive charge and colloidal stability of the as prepaired nanoparticles. The high affinity of these nanoparticles to anions is verified by spectrophotometric measurements with dye molecules, namely phenol red.
The Journal of Physical Chemistry C, 2010
Novel silica nanoparticles exhibiting near-infrared (NIR) and dual NIR-visible emission were synt... more Novel silica nanoparticles exhibiting near-infrared (NIR) and dual NIR-visible emission were synthesized according to reverse microemulsion procedure through the encapsulation of Yb(III) complex with p-sulfonatothiacalix[4]arene (Yb) and [Ru(dipy) 3 ]Cl 2 (Ru) as NIR-and visible-emitting luminophores into silica matrix. The synthesis was carried out at various Yb:Ru molar ratio. The numbers of Ru and Yb complexes per one nanoparticle were calculated from both fluorimetric and inductively coupled plasma atomic emission spectroscopy data. The dynamic light scattering measurements of aqueous dispersions of Yb, Ru, and Ru-Yb nanoparticles elucidate the relationship between the complexes inserted into nanoparticles and their aqueous dispersity. The transmission electron microscopy images were used to measure the size of the nanoparticles. The atomic force microscopy images reveal the different aggregation morphology of Yb-and Ru-doped nanoparticles.
Talanta, 2012
The work represents colloids of silica nanoparticles displaying fluorescent response on bioreleva... more The work represents colloids of silica nanoparticles displaying fluorescent response on biorelevant compounds exemplified by phosphacoumarins and phospholipids. The luminescent properties of the colloids arise from Tb(III) complexes doped into silica nanoparticles (SNs). The noncovalent decoration of SNs by dicationic surfactant with further interfacial binding of dye anions enables to develop colloids programmed to display a substrate induced fluorescent response. The latter results from the quenching of Tb(III) centered luminescence by dye anions through dynamic mechanism and subsequent displacement of quenching anions by the non-quenching substrates from the interface of SNs. Both negative charge and hydrophobicity of substrates are the key factors affecting the selectivity of the substrate induced fluorescent response. The peculiar effects of zwitter-ionic and anionic phospholipids on the fluorescent response have been revealed. The applicability of the fluorescent procedure in the sensing of impurities in commercial phosphatidylcholine is also introduced.
Langmuir, 2009
Novel silica-coated Tb(III) nanoparticles with high luminecsence were synthesized using the rever... more Novel silica-coated Tb(III) nanoparticles with high luminecsence were synthesized using the reverse microemulsion procedure. The quenching of luminescent properties of these nanoparticles can be achieved by ion exchange and energy transfer mechanisms. The quenching through the ion exchange of Tb(III) by H + or La(III) is time dependent, indicating that the ion exchange is probably diffusion controlled. The quenching by Co(III) complex cations is achieved by the energy transfer mechanism and thus is not time dependent. The analysis of quenching data in Stern-Volmer cooordinates reveal the negative charge of the silica-coated Tb(III)-TCAS nanoparticles and several types of luminophoric species, located within the core and close to the surface of silica nanoparticles.
Journal of Physics: Conference Series, 2011
Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR ... more Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR luminescence (Ru-Yb doped) were obtained by reverse w/o microemulsion procedure. Plenty of luminescent complexes (from 4900 to 10000) encapsulated into each nanoparticle ensures the intensive luminescence of nanoparticles and their applicability as biomarkers. The silica surface decoration by definite anchor groups is the required
Journal of Colloid and Interface Science, 2011
The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied i... more The aggregation and cloud point behavior of Tb(III)-doped silica nanoparticles has been studied in Triton X-100 (TX-100) solutions at various concentration conditions by fluorimetry, dynamic light scattering, electrophoresis and transmission electron microscopy methods. The temperature responsive behavior of nanoparticles is observed at definite concentration of TX-100, where the aggregation of TX-100 at the silica/water interface is evident from the increased size of the silica nanoparticles. The reversible dehydration of TX-100 aggregates at the silica/water interface should be assumed as the main reason of the temperature induced phase separation of silica nanoparticles. The distribution of nanoparticles between aqueous and surfactant rich phases at the phase separation conditions can be modified by the effect of additives.
Colloids and Surfaces B: Biointerfaces, 2012
The quenching effect of dyes (phenol red and bromothymol blue) on Tb(III)-centered luminescence e... more The quenching effect of dyes (phenol red and bromothymol blue) on Tb(III)-centered luminescence enables to sense the aggregation of cationic and anionic surfactants near the silica surface of Tb-doped silica nanoparticles (SN) in aqueous solutions. The Tb-centered luminescence of non-decorated SNs is diminished by the inner filter effect of both dyes. The decoration of the silica surface by cationic surfactants induces the quenching through the energy transfer between silica coated Tb(III) complexes and dye anions inserted into surfactant aggregates. Thus the distribution of surfactants aggregates at the silica/water interface and in the bulk of solution greatly affects dynamic quenching efficiency. The displacement of dye anions from the interfacial surfactant adlayer by anionic surfactants and phospholipids is accompanied by the "off-on" switching of Tb(III)-centered luminescence.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2011
The present work introduces the interaction of hard and soft colloids in aqueous solutions at var... more The present work introduces the interaction of hard and soft colloids in aqueous solutions at various temperatures and concentrations, as well as at critical conditions of temperature induced phase separation. Hard and soft colloids are represented by luminescent silica nanoparticles and aggregates of PEO-PPO-PEO and PPO-PEO-PPO triblock copolymers correspondingly. The formation of the mixed aggregates between hard and soft colloids in equilibrium conditions has been revealed by dynamic light scattering measurements. The distribution of silica nanoparticles between aqueous and surfactant rich phases after phase separation highlights the effect of pH, architecture and concentration of triblock copolymers on the mixed hard-soft colloids aggregation at cloud point conditions. The peculiar aggregation and phase behavior of PPO-PEO-PPO pluronics should be assumed as the main reason of the enhanced mixed aggregation with SNs at increased temperatures and concentrated conditions.
Russian Chemical Bulletin, 2008
The conditions for the formation of heteroleptic complexes of a lanthanide(III) ion (Ln = La, Gd,... more The conditions for the formation of heteroleptic complexes of a lanthanide(III) ion (Ln = La, Gd, and Tb) with p sulfonatothiacalix[4]arene and a heteroaromatic chromophore in water were found using X ray diffraction analysis, pH metry, 1 H NMR and UV-Vis spectros copy, and nuclear magnetic relaxation. In the resulting complexes, the heteroaromatic chro mophore is in the calix[4]arene cavity and the lanthanide ion is coordinated by the electron donating groups of the upper or lower calix[4]arene rim. Emission spectroscopic studies re vealed changed emission properties of Tb III ions in the terbium(III)-p sulfonatothia calix[4]arene-bipy complex.