Chandani Perera - Academia.edu (original) (raw)

Papers by Chandani Perera

Asian Journal of Chemistry, 2023

This work reports the synthesis of silver nanoparticles (AgNPs) using the leaf extract of Annona ... more This work reports the synthesis of silver nanoparticles (AgNPs) using the leaf extract of Annona glabra as a green synthetic route and assessment of its photocatalytic property using methelyne blue as a model dye and toxic effect against an aquatic model, Daphnia magna. Leaf extract prepared at 100 ºC, 1% plant extract, 1 mM of AgNO3, 3 h incubation time were optimized for the synthesis of AgNPs. Surface plasmon resonance peak of AgNPs laid around 419 nm. Spherical nanoparticles were in the size ranges 50-80 and 110-195 nm. Biomolecules were present as capping agents on AgNPs. AgNPs have cubic face centered lattice structure and the average particle size as calculated using Debye-Scherrer formula is 55 nm. Green synthesized AgNPs reduced the absorbance of methelyne blue dye by 89% in 3 h showing prominent photocatalytic activity. The EC50 of AgNPs was found to be 1.78 ± 0.20 mg/L against Daphnia magna showing a lower toxicity than silver ions.

Proceedings of SPIE, Apr 30, 2003

ABSTRACT

Liquid Crystals, Oct 13, 2017

ABSTRACT A selenium-containing compound, AS657, is studied with two complementary methods, electr... more ABSTRACT A selenium-containing compound, AS657, is studied with two complementary methods, electric-field-induced birefringence (EFIB) and microbeam resonant X-ray scattering (µRXS). AS657 shows a phase sequence of Sm – – – Sm – Sm where no Sm emerges and hence the frustration between Sm and Sm plays an important role. In spite of this situation, two additional temperature-induced subphases are observed: (1) antiferroelectric eight-layer between Sm and and (2) antiferroelectric 10-layer between and . A number of field-induced subphases are also shown to emerge. The most notable new finding is the observation of an electric-field-induced ferrielectric subphase of six-layer () between and Sm; this subphase is stabilised even at zero field in a mixture of 92.6 wt% AS657 and 7.4 wt% AS620. Another field-induced subphase of six-layer is also confirmed to emerge in the temperature ranges of SmCA* and . The nature of the field-induced transitions in the temperature range is more complex than previously thought; in its high temperature range, wound (not unwound) Sm with some macroscopic distorted helical director arrangement reappears above , whereas in the low temperature range, some intriguing sequential field-induced transitions are observed both in the EFIB and µRXS. Last but not the least is the observation of a field-induced subphase found in the low-temperature range of by EFIB and this is tentatively assigned as , the detailed structure of which is expected to be clarified by µRXS in the near future. Graphical Abstract

Proceedings of SPIE - The International Society for Optical Engineering, 2003

International Journal of Pharmaceutics, 2016

A novel, efficient delivery system for iron (Fe 2+) was developed using the alginate biopolymer. ... more A novel, efficient delivery system for iron (Fe 2+) was developed using the alginate biopolymer. Iron loaded alginate nanoparticles were synthesized by a controlled ionic gelation method and was characterized with respect to particle size, zeta potential, morphology and encapsulation efficiency. Successful loading was confirmed with Fourier Transform Infrared spectroscopy and Thermogravimetric Analysis. Electron energy loss spectroscopy study corroborated the loading of ferrous into the alginate nanoparticles. Iron encapsulation (70%) was optimized at 0.06% Fe (w/v) leading to the formation of iron loaded alginate nanoparticles with a size range of 15-30 nm and with a negative zeta potential (-38 mV). The in vitro release studies showed a prolonged release profile for 96 h. Release of iron was around 65-70% at pH of 6 and 7.4 whereas it was less than 20% at pH 2. The initial burst release upto 8 h followed zero order kinetics at all three pH values. All the release profiles beyond 8 h best fitted the Korsmeyer-Peppas model of diffusion. Non Fickian diffusion was observed at pH 6 and 7.4 while at pH 2 Fickian diffusion was observed.

Ceylon Journal of Science, 2021

Development of novel advanced materials for water softening applications is a timely need. Water ... more Development of novel advanced materials for water softening applications is a timely need. Water softening efficiency of activated and pyrolyzed coconut coir (PCC) was found to be higher than that of activated carbon derived from coconut shell charcoal. For further enhancing the water softening capacity of PCC, magnetite nanoparticles impregnated pyrolyzed coconut coir (M-PCC) was synthesized by an in-situ one-pot synthesis method. In this approach, the raw coconut coir was dipped in a solution of 1.00 mol dm-3 FeCl 3 , 1.00 mol dm-3 FeSO 4 .7H 2 O and 5.00 mol dm-3 NaOH followed by pyrolysis at 450 ℃ under N 2 gas flow and evaluated its efficiency in water softening applications. The process parameters, including contact time, adsorbent dose and pH, were optimized using a representative natural water sample (total hardness-370 mol L-1). Characterization studies confirmed the successful impregnation of magnetite nanoparticles into pyrolyzed coconut coir. Powder X-ray diffraction and Fourier transform infrared spectroscopy confirmed the formation of magnetite phase and provided information on interactions with the carbon matrix. M-PCC thus prepared was capable of removing total hardness of natural hard water over 80% with an adsorbent dose of 0.6 g/50 mL at a water pH of 6-8 by double filtration. Therefore, it can be claimed that magnetite nanoparticles impregnated pyrolyzed coconut coir is suitable as an adept adsorption material in developing next-generation methodologies for restoring water softness.

The broader socioeconomic impact anticipated to occur in the coming decades with the advent of na... more The broader socioeconomic impact anticipated to occur in the coming decades with the advent of nanoscience and nanotechnology has led many countries to establish national nanotechnology initiatives to promote nanotechnological developments. One major resolution under these mega initiatives is to popularise nanotechnology as a subject at the high school and university levels. However, teaching nanotechnology concepts at the high school level still remains challenging mainly due to the inherent complexity of the associated principles and the unavailability of resourceful talents to teach the subject. Herein, we disclose the development of a nanoscience and nanotechnology educational tool kit for innovative and interactive teaching and learning of nanotechnology at the high school level. This portable tool kit includes several interactive activities such as puzzles and games to understand and visualize nano-scale, synthesis of simple nanomaterials with readily available chemicals, expe...

DESALINATION AND WATER TREATMENT, 2021

Activated coconut coir (ACC) was prepared by activation of raw coconut coir dust with 50 wt.% pho... more Activated coconut coir (ACC) was prepared by activation of raw coconut coir dust with 50 wt.% phosphoric acid followed by pyrolysis at 450°C in a nitrogen atmosphere. ACC demonstrated high efficacy in the removal of Cd(II) from aqueous solutions. Batch adsorption studies were carried out to study the effect of adsorbent dose, agitation time, pH and initial concentration of Cd(II) on the adsorption of Cd(II) on ACC. It was found that adsorption equilibrium was achieved rapidly within 10 min of agitation time and 98% of Cd(II) was removed from 10.00 mg L–1 Cd(II) solution at pH of 6 with 0.200 g of ACC. The rate of adsorption of Cd(II) on ACC followed pseudo-second-order kinetics. The equilibrium adsorption obeys linear Langmuir isotherm model for Cd(II) concentrations in the range of 10.00–100.00 mg L–1, whereas, in the entire concentration range of Cd(II) from 10.00 to 664.00 mg L–1, adsorption obeys non-linear Freundlich isotherm model. The maximum Cd(II) adsorption capacity of ACC...

The main objective of this study is to evaluate the suitability of Murunkan clay, a natural clay ... more The main objective of this study is to evaluate the suitability of Murunkan clay, a natural clay found in Murunkan, Mannar and coconut coir as low cost filter materials for desalination of water. Percentage removal of Na + , K + , Mg 2+ and Ca 2+ cations by these filter materials was studied. Water taken from Negombo lagoon was stirred in clay for 30 minutes followed by keeping in contact for different time periods of 0.5, 1, 2, 3, 4 and 24 hours using raw Murunkan clay. The same procedure was followed using acid treated clay up to 4 hours. To evaluate ion adsorption capacity of individual coconut coir types; red coir, pith-free coir and activated coir, lagoon water samples were passed through columns containing packed coir. Furthermore, the water samples were passed through a column combination of three types of coir after stirring in the clay for an optimum time period. The efficiency of raw Murunkan clay, acid treated Murunkan clay and three types of coir was evaluated for lagoon water containing Na + , K + , Mg 2+ and Ca 2+ 31,705, 639, 3,139 and 1,029 ppm respectively. The highest percentage removal of ions was observed when lagoon water treated with raw Murunkan clay was used in column combination with coir, leading to the percentage removal of 50%, 52%, 63% and 85% for Na + , K + , Mg 2+ and Ca 2+ respectively with a flow rate of 0.05 ml s-1 .

Environmental Science: Water Research & Technology

This study reports the synthesis and characterization of a phosphate functionalized porous activa... more This study reports the synthesis and characterization of a phosphate functionalized porous activated carbon filter material suitable for sachet filters to remove fluoride, hardness and bacterial pathogens in drinking water.

ACS Omega

Thermal instability, photodegradation, and poor bioavailability of natural active ingredients are... more Thermal instability, photodegradation, and poor bioavailability of natural active ingredients are major drawbacks in developing effective natural product-based antimicrobial formulations. These inherited issues could be fruitfully mitigated by the introduction of natural active ingredients into various nanostructures. This study focuses on the development of a novel green mechanochemical synthetic route to incorporate curcuminoids into Mg-Al-layered double hydroxides. The developed one-pot and scalable synthetic approach makes lengthy synthesis procedures using toxic solvents redundant, leading to improved energy efficiency. The hydrotalcite-shaped nanohybrids consist of surface and interlayer curcuminoids that have formed weak bonds with layered double hydroxides as corroborated by X-ray diffractograms, X-ray photoelectron spectra, and Fourier transmission infrared spectra. The structural and morphological properties resulted in increased thermal stability of curcuminoids. Slow and sustained release of the curcuminoids was observed at pH 5.5 for a prolonged time up to 7 h. The developed nanohybrids exhibited zeroth-order kinetics, favoring transdermal application. Furthermore, the efficacy of curcuminoid incorporated LDHs (CC-LDH) as an anticolonization agent was investigated against four wound biofilm-forming pathogens, Pseudomonas aeruginosa, Staphylococcus aureus, methicillin-resistant Staphyloccocus aureus, and Candida albicans, using a broth dilution method and an in vitro biofilm model system. Microbiological studies revealed a 54−58% reduction in biofilm formation ability of bacterial pathogens in developed nanohybrids compared to pure curcuminoids. Therefore, the suitability of these green-chemically synthesized CC-LDH nanohybrids for next-generation antimicrobial applications with advanced dermatological/medical properties is well established.

Physical Review E

The unique nanometer-sized helical structure in SmC * α may sometimes evolve continuously to the ... more The unique nanometer-sized helical structure in SmC * α may sometimes evolve continuously to the micrometersized one in SmC * ; conceivably ferroelectric SmC * α is to be unwound by an applied electric field. By drawing electric-field-induced birefringence contours in the field-temperature phase diagram and by studying the superlattice structure of the field-induced subphase with resonant x-ray scattering, we established that an applied field unexpectedly stabilizes the well-known antiferroelectric four-layer biaxial subphase as well as the other prototypal ferrielectric three-layer one in the SmC * α temperature range; the effective long-range interlayer interaction due to the discrete flexoelectric effect actually plays an important role in stabilizing not only the biaxial subphases but also the optically uniaxial SmC * α subphase, contrary to the notion that the competition between the direct interactions of the nearest-neighbor layers and those of the next-nearest-neighbor layers should be required for the nanometer-sized helical structure.

DESALINATION AND WATER TREATMENT, 2017

DESALINATION AND WATER TREATMENT, 2017

Journal of Nanomaterials, 2016

A chitosan-alginate nanoparticle system encapsulating doxorubicin (DOX) was prepared by a novel i... more A chitosan-alginate nanoparticle system encapsulating doxorubicin (DOX) was prepared by a novel ionic gelation method using alginate as the crosslinker. These nanoparticles were around 100 nm in size and more stable with higher positive zeta potential and had higher % encapsulation efficiency (95%) than DOX loaded chitosan nanoparticles (DOX Csn NP) crosslinked with sodium tripolyphosphate (STPP). FTIR spectroscopy and thermogravimetric analysis revealed successful loading of DOX.In vitrodrug release showed an initial release phase followed by slow release phase with higher cumulative release obtained with DOX loaded chitosan-alginate nanoparticles (DOX Csn-Alg NP). Thein vitrocytotoxicity of DOX released from the two nanoparticle systems showed a notable difference on comparison with that of free DOX on the MCF-7 cell line. The SRB assay, AO/EB staining, and fluorescence uptake study indicated that free DOX only showed dose dependent cytotoxicity, whereas both dose and time depende...

International Journal of Pharmaceutics, 2016

Journal of Nanomaterials, 2016

Photoageing resulting from long term exposure of the skin to UV light can be minimized by scaveng... more Photoageing resulting from long term exposure of the skin to UV light can be minimized by scavenging the reactive photochemical intermediates with antioxidants. For effective photoprotection, the antioxidant must overcome the barrier properties of the skin and reach the target site in significant amounts. The present study aims to improve the skin penetration of caffeic acid, a very effective free radical scavenger, by encapsulating in liposomes. Caffeic acid loaded liposomes prepared using the reverse phase evaporation technique showed 70% encapsulation efficiency and size around 100 nm with zeta potential of −55 mV.In vitrodiffusion through a dialysis membrane enabled 70% release of encapsulated caffeic acid within 7 h, whereas 95% of free caffeic acid diffused within 4 h in PBS solution (pH 7.4). Liposomal caffeic acid permeation through pig skin epidermis in a Franz cell apparatus was 45 % during 7 h. In contrast, free caffeic acid was almost nonpermeable (<5%) to pig skin du...

Asian Journal of Chemistry, 2023

This work reports the synthesis of silver nanoparticles (AgNPs) using the leaf extract of Annona ... more This work reports the synthesis of silver nanoparticles (AgNPs) using the leaf extract of Annona glabra as a green synthetic route and assessment of its photocatalytic property using methelyne blue as a model dye and toxic effect against an aquatic model, Daphnia magna. Leaf extract prepared at 100 ºC, 1% plant extract, 1 mM of AgNO3, 3 h incubation time were optimized for the synthesis of AgNPs. Surface plasmon resonance peak of AgNPs laid around 419 nm. Spherical nanoparticles were in the size ranges 50-80 and 110-195 nm. Biomolecules were present as capping agents on AgNPs. AgNPs have cubic face centered lattice structure and the average particle size as calculated using Debye-Scherrer formula is 55 nm. Green synthesized AgNPs reduced the absorbance of methelyne blue dye by 89% in 3 h showing prominent photocatalytic activity. The EC50 of AgNPs was found to be 1.78 ± 0.20 mg/L against Daphnia magna showing a lower toxicity than silver ions.

Proceedings of SPIE, Apr 30, 2003

ABSTRACT

Liquid Crystals, Oct 13, 2017

ABSTRACT A selenium-containing compound, AS657, is studied with two complementary methods, electr... more ABSTRACT A selenium-containing compound, AS657, is studied with two complementary methods, electric-field-induced birefringence (EFIB) and microbeam resonant X-ray scattering (µRXS). AS657 shows a phase sequence of Sm – – – Sm – Sm where no Sm emerges and hence the frustration between Sm and Sm plays an important role. In spite of this situation, two additional temperature-induced subphases are observed: (1) antiferroelectric eight-layer between Sm and and (2) antiferroelectric 10-layer between and . A number of field-induced subphases are also shown to emerge. The most notable new finding is the observation of an electric-field-induced ferrielectric subphase of six-layer () between and Sm; this subphase is stabilised even at zero field in a mixture of 92.6 wt% AS657 and 7.4 wt% AS620. Another field-induced subphase of six-layer is also confirmed to emerge in the temperature ranges of SmCA* and . The nature of the field-induced transitions in the temperature range is more complex than previously thought; in its high temperature range, wound (not unwound) Sm with some macroscopic distorted helical director arrangement reappears above , whereas in the low temperature range, some intriguing sequential field-induced transitions are observed both in the EFIB and µRXS. Last but not the least is the observation of a field-induced subphase found in the low-temperature range of by EFIB and this is tentatively assigned as , the detailed structure of which is expected to be clarified by µRXS in the near future. Graphical Abstract

Proceedings of SPIE - The International Society for Optical Engineering, 2003

International Journal of Pharmaceutics, 2016

A novel, efficient delivery system for iron (Fe 2+) was developed using the alginate biopolymer. ... more A novel, efficient delivery system for iron (Fe 2+) was developed using the alginate biopolymer. Iron loaded alginate nanoparticles were synthesized by a controlled ionic gelation method and was characterized with respect to particle size, zeta potential, morphology and encapsulation efficiency. Successful loading was confirmed with Fourier Transform Infrared spectroscopy and Thermogravimetric Analysis. Electron energy loss spectroscopy study corroborated the loading of ferrous into the alginate nanoparticles. Iron encapsulation (70%) was optimized at 0.06% Fe (w/v) leading to the formation of iron loaded alginate nanoparticles with a size range of 15-30 nm and with a negative zeta potential (-38 mV). The in vitro release studies showed a prolonged release profile for 96 h. Release of iron was around 65-70% at pH of 6 and 7.4 whereas it was less than 20% at pH 2. The initial burst release upto 8 h followed zero order kinetics at all three pH values. All the release profiles beyond 8 h best fitted the Korsmeyer-Peppas model of diffusion. Non Fickian diffusion was observed at pH 6 and 7.4 while at pH 2 Fickian diffusion was observed.

Ceylon Journal of Science, 2021

Development of novel advanced materials for water softening applications is a timely need. Water ... more Development of novel advanced materials for water softening applications is a timely need. Water softening efficiency of activated and pyrolyzed coconut coir (PCC) was found to be higher than that of activated carbon derived from coconut shell charcoal. For further enhancing the water softening capacity of PCC, magnetite nanoparticles impregnated pyrolyzed coconut coir (M-PCC) was synthesized by an in-situ one-pot synthesis method. In this approach, the raw coconut coir was dipped in a solution of 1.00 mol dm-3 FeCl 3 , 1.00 mol dm-3 FeSO 4 .7H 2 O and 5.00 mol dm-3 NaOH followed by pyrolysis at 450 ℃ under N 2 gas flow and evaluated its efficiency in water softening applications. The process parameters, including contact time, adsorbent dose and pH, were optimized using a representative natural water sample (total hardness-370 mol L-1). Characterization studies confirmed the successful impregnation of magnetite nanoparticles into pyrolyzed coconut coir. Powder X-ray diffraction and Fourier transform infrared spectroscopy confirmed the formation of magnetite phase and provided information on interactions with the carbon matrix. M-PCC thus prepared was capable of removing total hardness of natural hard water over 80% with an adsorbent dose of 0.6 g/50 mL at a water pH of 6-8 by double filtration. Therefore, it can be claimed that magnetite nanoparticles impregnated pyrolyzed coconut coir is suitable as an adept adsorption material in developing next-generation methodologies for restoring water softness.

The broader socioeconomic impact anticipated to occur in the coming decades with the advent of na... more The broader socioeconomic impact anticipated to occur in the coming decades with the advent of nanoscience and nanotechnology has led many countries to establish national nanotechnology initiatives to promote nanotechnological developments. One major resolution under these mega initiatives is to popularise nanotechnology as a subject at the high school and university levels. However, teaching nanotechnology concepts at the high school level still remains challenging mainly due to the inherent complexity of the associated principles and the unavailability of resourceful talents to teach the subject. Herein, we disclose the development of a nanoscience and nanotechnology educational tool kit for innovative and interactive teaching and learning of nanotechnology at the high school level. This portable tool kit includes several interactive activities such as puzzles and games to understand and visualize nano-scale, synthesis of simple nanomaterials with readily available chemicals, expe...

DESALINATION AND WATER TREATMENT, 2021

Activated coconut coir (ACC) was prepared by activation of raw coconut coir dust with 50 wt.% pho... more Activated coconut coir (ACC) was prepared by activation of raw coconut coir dust with 50 wt.% phosphoric acid followed by pyrolysis at 450°C in a nitrogen atmosphere. ACC demonstrated high efficacy in the removal of Cd(II) from aqueous solutions. Batch adsorption studies were carried out to study the effect of adsorbent dose, agitation time, pH and initial concentration of Cd(II) on the adsorption of Cd(II) on ACC. It was found that adsorption equilibrium was achieved rapidly within 10 min of agitation time and 98% of Cd(II) was removed from 10.00 mg L–1 Cd(II) solution at pH of 6 with 0.200 g of ACC. The rate of adsorption of Cd(II) on ACC followed pseudo-second-order kinetics. The equilibrium adsorption obeys linear Langmuir isotherm model for Cd(II) concentrations in the range of 10.00–100.00 mg L–1, whereas, in the entire concentration range of Cd(II) from 10.00 to 664.00 mg L–1, adsorption obeys non-linear Freundlich isotherm model. The maximum Cd(II) adsorption capacity of ACC...

The main objective of this study is to evaluate the suitability of Murunkan clay, a natural clay ... more The main objective of this study is to evaluate the suitability of Murunkan clay, a natural clay found in Murunkan, Mannar and coconut coir as low cost filter materials for desalination of water. Percentage removal of Na + , K + , Mg 2+ and Ca 2+ cations by these filter materials was studied. Water taken from Negombo lagoon was stirred in clay for 30 minutes followed by keeping in contact for different time periods of 0.5, 1, 2, 3, 4 and 24 hours using raw Murunkan clay. The same procedure was followed using acid treated clay up to 4 hours. To evaluate ion adsorption capacity of individual coconut coir types; red coir, pith-free coir and activated coir, lagoon water samples were passed through columns containing packed coir. Furthermore, the water samples were passed through a column combination of three types of coir after stirring in the clay for an optimum time period. The efficiency of raw Murunkan clay, acid treated Murunkan clay and three types of coir was evaluated for lagoon water containing Na + , K + , Mg 2+ and Ca 2+ 31,705, 639, 3,139 and 1,029 ppm respectively. The highest percentage removal of ions was observed when lagoon water treated with raw Murunkan clay was used in column combination with coir, leading to the percentage removal of 50%, 52%, 63% and 85% for Na + , K + , Mg 2+ and Ca 2+ respectively with a flow rate of 0.05 ml s-1 .

Environmental Science: Water Research & Technology

This study reports the synthesis and characterization of a phosphate functionalized porous activa... more This study reports the synthesis and characterization of a phosphate functionalized porous activated carbon filter material suitable for sachet filters to remove fluoride, hardness and bacterial pathogens in drinking water.

ACS Omega

Thermal instability, photodegradation, and poor bioavailability of natural active ingredients are... more Thermal instability, photodegradation, and poor bioavailability of natural active ingredients are major drawbacks in developing effective natural product-based antimicrobial formulations. These inherited issues could be fruitfully mitigated by the introduction of natural active ingredients into various nanostructures. This study focuses on the development of a novel green mechanochemical synthetic route to incorporate curcuminoids into Mg-Al-layered double hydroxides. The developed one-pot and scalable synthetic approach makes lengthy synthesis procedures using toxic solvents redundant, leading to improved energy efficiency. The hydrotalcite-shaped nanohybrids consist of surface and interlayer curcuminoids that have formed weak bonds with layered double hydroxides as corroborated by X-ray diffractograms, X-ray photoelectron spectra, and Fourier transmission infrared spectra. The structural and morphological properties resulted in increased thermal stability of curcuminoids. Slow and sustained release of the curcuminoids was observed at pH 5.5 for a prolonged time up to 7 h. The developed nanohybrids exhibited zeroth-order kinetics, favoring transdermal application. Furthermore, the efficacy of curcuminoid incorporated LDHs (CC-LDH) as an anticolonization agent was investigated against four wound biofilm-forming pathogens, Pseudomonas aeruginosa, Staphylococcus aureus, methicillin-resistant Staphyloccocus aureus, and Candida albicans, using a broth dilution method and an in vitro biofilm model system. Microbiological studies revealed a 54−58% reduction in biofilm formation ability of bacterial pathogens in developed nanohybrids compared to pure curcuminoids. Therefore, the suitability of these green-chemically synthesized CC-LDH nanohybrids for next-generation antimicrobial applications with advanced dermatological/medical properties is well established.

Physical Review E

The unique nanometer-sized helical structure in SmC * α may sometimes evolve continuously to the ... more The unique nanometer-sized helical structure in SmC * α may sometimes evolve continuously to the micrometersized one in SmC * ; conceivably ferroelectric SmC * α is to be unwound by an applied electric field. By drawing electric-field-induced birefringence contours in the field-temperature phase diagram and by studying the superlattice structure of the field-induced subphase with resonant x-ray scattering, we established that an applied field unexpectedly stabilizes the well-known antiferroelectric four-layer biaxial subphase as well as the other prototypal ferrielectric three-layer one in the SmC * α temperature range; the effective long-range interlayer interaction due to the discrete flexoelectric effect actually plays an important role in stabilizing not only the biaxial subphases but also the optically uniaxial SmC * α subphase, contrary to the notion that the competition between the direct interactions of the nearest-neighbor layers and those of the next-nearest-neighbor layers should be required for the nanometer-sized helical structure.

DESALINATION AND WATER TREATMENT, 2017

DESALINATION AND WATER TREATMENT, 2017

Journal of Nanomaterials, 2016

A chitosan-alginate nanoparticle system encapsulating doxorubicin (DOX) was prepared by a novel i... more A chitosan-alginate nanoparticle system encapsulating doxorubicin (DOX) was prepared by a novel ionic gelation method using alginate as the crosslinker. These nanoparticles were around 100 nm in size and more stable with higher positive zeta potential and had higher % encapsulation efficiency (95%) than DOX loaded chitosan nanoparticles (DOX Csn NP) crosslinked with sodium tripolyphosphate (STPP). FTIR spectroscopy and thermogravimetric analysis revealed successful loading of DOX.In vitrodrug release showed an initial release phase followed by slow release phase with higher cumulative release obtained with DOX loaded chitosan-alginate nanoparticles (DOX Csn-Alg NP). Thein vitrocytotoxicity of DOX released from the two nanoparticle systems showed a notable difference on comparison with that of free DOX on the MCF-7 cell line. The SRB assay, AO/EB staining, and fluorescence uptake study indicated that free DOX only showed dose dependent cytotoxicity, whereas both dose and time depende...

International Journal of Pharmaceutics, 2016

Journal of Nanomaterials, 2016

Photoageing resulting from long term exposure of the skin to UV light can be minimized by scaveng... more Photoageing resulting from long term exposure of the skin to UV light can be minimized by scavenging the reactive photochemical intermediates with antioxidants. For effective photoprotection, the antioxidant must overcome the barrier properties of the skin and reach the target site in significant amounts. The present study aims to improve the skin penetration of caffeic acid, a very effective free radical scavenger, by encapsulating in liposomes. Caffeic acid loaded liposomes prepared using the reverse phase evaporation technique showed 70% encapsulation efficiency and size around 100 nm with zeta potential of −55 mV.In vitrodiffusion through a dialysis membrane enabled 70% release of encapsulated caffeic acid within 7 h, whereas 95% of free caffeic acid diffused within 4 h in PBS solution (pH 7.4). Liposomal caffeic acid permeation through pig skin epidermis in a Franz cell apparatus was 45 % during 7 h. In contrast, free caffeic acid was almost nonpermeable (<5%) to pig skin du...