Browsing by Author "Deepika, D."

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Sacrificial polystyrene template assisted synthesis of tunable pore size hollow core-shell silica nanoparticles (HCSNs) for drug delivery application
(2019) Deepika, D.; Jagadeeshbabu, P.E.
Hollow core-shell silica nanoparticles (HCSNs) with desirable interior space have attracted intensive interest in the field of controlled drug delivery. In the present research work facile two-step method was employed to synthesize HCSNs by using sacrificial polystyrene (PS) template. Monodispersed spherical polystyrene nanoparticles with size range 200-250 nm were synthesized by emulsion polymerization method. Silica was coated on PS template using TEOS as precursor and cetyltrimethyl ammonium bromide (CTAB) as the shell structure directing agent. Complete removal of the template particles was achieved by calcination at 550 �C confirmed by fourier transform infrared spectroscopy (FTIR). Variation in pore size was attained by altering ethanol/water volume ratio and visualized in scanning electron microscope (SEM). Average specific surface area of HCSNs verified by Brunauer Emmett Teller (BET) method observed to be 842.57 m2/g. Drug release behavior was investigated using doxorubicin as model drug by varying pore size of HCSNs, displayed a pore size dependent release. HCSNs with reduced pore size (2.2 nm) showed maximum delay in the doxorubicin release, demonstrated the potential application of HCSNs in targeted drug delivery. � 2019 Author(s).
Sacrificial polystyrene template assisted synthesis of tunable pore size hollow core-shell silica nanoparticles (HCSNs) for drug delivery application
(American Institute of Physics Inc. subs@aip.org, 2019) Deepika, D.; JagadeeshBabu, J.
Hollow core-shell silica nanoparticles (HCSNs) with desirable interior space have attracted intensive interest in the field of controlled drug delivery. In the present research work facile two-step method was employed to synthesize HCSNs by using sacrificial polystyrene (PS) template. Monodispersed spherical polystyrene nanoparticles with size range 200-250 nm were synthesized by emulsion polymerization method. Silica was coated on PS template using TEOS as precursor and cetyltrimethyl ammonium bromide (CTAB) as the shell structure directing agent. Complete removal of the template particles was achieved by calcination at 550 Â°C confirmed by fourier transform infrared spectroscopy (FTIR). Variation in pore size was attained by altering ethanol/water volume ratio and visualized in scanning electron microscope (SEM). Average specific surface area of HCSNs verified by Brunauer Emmett Teller (BET) method observed to be 842.57 m2/g. Drug release behavior was investigated using doxorubicin as model drug by varying pore size of HCSNs, displayed a pore size dependent release. HCSNs with reduced pore size (2.2 nm) showed maximum delay in the doxorubicin release, demonstrated the potential application of HCSNs in targeted drug delivery. Â© 2019 Author(s).
Synthesis and characterization of microporous hollow core-shell silica nanoparticles (HCSNs) of tunable thickness for controlled release of doxorubicin
(Springer Netherlands rbk@louisiana.edu, 2018) Deepika, D.; JagadeeshBabu, J.B.
Hollow core-shell silica nanoparticles (HCSNs) are being considered as one of the most favorable drug carriers to accomplish targeted drug delivery. In the present study, we developed a simple two-step method, employing polystyrene (PS) nanoparticles (150 ± 20 nm) as a sacrificial template for the synthesis of microporous HCSNs of size 230 ± 30 nm. PS core and the wall structure directing agent cetyl trimethyl ammonium bromide (CTAB) were removed by calcination. Monodispersed spherical HCSNs were synthesized by optimising the parameters like water/ethanol volume ratio, PS/tetraethyl orthosilicate (TEOS) weight ratio, concentration of ammonia, and CTAB. Transmission electron microscopy (TEM) revealed the formation of hollow core-shell structure of silica with tunable thickness from 15 to 30 nm while tailoring the concentration of silica precursor. The results obtained from the cumulative release studies of doxorubicin loaded microporous HCSNs demonstrated the dependence of shell thickness on the controlled drug release behavior. HCSNs with highest shell thickness of 30 nm and lowest surface area of 600 m2/g showed delay in the doxorubicin release, proving their application as a drug carrier in targeted drug delivery systems. The novel concept of application of microporous HCSNs of pore size ~ 1.3 nm with large specific surface area in the field of drug delivery is successful. © 2018, Springer Nature B.V.
Synthesis of silica hollow core shell nanoparticles by sacrificial nitrated polystyrene template approach for targeted drug delivery application
(Elsevier Ltd, 2021) Deepika, D.; JagadeeshBabu, P.E.
Silica hollow core shell nanoparticles (SHCNs) were synthesized by employing nitrated polystyrene as sacrificial template. Polystyrene (PS) nanoparticles were functionalized with nitro functional group to modify the surface properties and to enhance the pore size of SHCNs. Calcination of silica coated nitrated PS nanoparticles lead to the formation of SHCNs and no traces of the polymer particles were found inside SHCNs as analyzed in fourier transform infrared radiation (FTIR). Transmission electron microscope (TEM) images were used to analyze the shell thickness of silica which was tuned between 15 and 35 nm. Specific surface area and average pore sizes of SHCNs were found to vary from 533.6 to 130.5 m2/g and 2.6 to 3.7 nm respectively. SHCNs were loaded with doxorubicin to evaluate the potential release kinetics by varying the silica shell thickness and pH of the release medium. SHCNs showed sustained release for 250 min at a pH of 7.4. Â© 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Advances in Materials Research - 2019.