Goldie Oza

Green synthesis of biocompatible carbon dots using aqueous extract of Trapa bispinosa peel

We are reporting highly economical plant based method for the production of luminescent water soluble carbon dots (C-dot) using Indian water plant Trapa bispinosa peel extract without adding any external oxidizing agent at 90 °C. C-dots ranging from 5 to 10nm were found in the solution with a prominent green fluorescence under UV-light (λex=365 nm). UV-vis spectra recorded at different time intervals (30-120 min) displayed signature absorption of C-dots between 400 and 600 nm. Fluorescence spectra of the dispersion after 120 min of synthesis exhibited characteristic emission peaks of C-dots when excited at 350, 400, 450 and 500 nm. C-dots were further analyzed using X-ray diffraction (XRD), Raman Spectroscopy and Thermo-Gravimetric Analysis (TGA). Structure of the C-dots was found to be turbostratic when studied using XRD. C-dots synthesized by our method were found to be exceptionally biocompatible against MDCK cells.

Folic acid mediated synaphic delivery of doxorubicin using biogenic gold nanoparticles anchored to biological linkers

Azadirachta indica as a biological sink for fabrication of gold nanoparticles (GNPs) and its applications in efficient delivery of doxorubicin (DOX) are presented here. Sucrose density gradient centrifugation was used to isolate the spherical GNPs of <50 nm from the mixture (containing both spherical and non-spherical) of nanoparticles synthesized using leaves of A. indica at inherent pH (6.14). The stability of GNPs due to the biological capping agents was scrutinised by measuring the flocculation parameter which was found to be in the range of 0-0.65. On the surface of these capped GNPs, doxorubicin was attached along with activated folic acid (FA) as navigational molecules for targeted drug delivery. Attachments were verified using FTIR which confirmed the formation of non-covalent interactions. The GNPs-FA-DOX complex was found be non-toxic for normal cells and considerably toxic for HeLa cells. The drug loading capacity of the GNPs was found to 93%. Doxorubicin release kinetics using GNPs followed 1st order at pH 5.3 which is ideal for solid tumor targeting.

Camphor-mediated synthesis of carbon nanoparticles, graphitic shell encapsulated carbon nanocubes and carbon dots for bioimaging

A green method for an efficient synthesis of water-soluble carbon nanoparticles (CNPs), graphitic shell encapsulated carbon nanocubes (CNCs), Carbon dots (CDs) using Camphor (Cinnamomum camphora) is demonstrated. Here, we describe a competent molecular fusion and fission route for step-wise synthesis of CDs. Camphor on acidification and carbonization forms CNPs, which on alkaline hydrolysis form CNCs that are encapsulated by thick graphitic layers and on further reduction by sodium borohydride yielded CDs. Though excitation wavelength dependent photoluminescence is observed in all the three carbon nanostructures, CDs possess enhanced photoluminescent properties due to more defective carbonaceous structures. The surface hydroxyl and carboxyl functional groups make them water soluble in nature. They possess excellent photostability, higher quantum yield, increased absorption, decreased cytotoxicity and hence can be utilized as a proficient bio imaging agent.

Understanding the stability of silver nanoparticles bio-fabricated using Acacia arabica (Babool gum) and its hostile effect on microorganisms.

We report green synthesis of stable silver nanoparticles (SNPs) from Acacia arabica gum and its anti-bacterial activity against gram-positive and gram-negative bacteria. UV-Vis spectral analysis of synthesized SNPs showed maximum peak at 462 nm initially and 435 nm after 24 h. Using Transmission Electron microscopy (TEM), the average size of synthesised SNPs was found to be ~35 nm. X-ray diffraction (XRD) and Selective area electron diffraction (SAED) pattern confirmed the crystalline nature of SNPs. Percentage conversion of Ag(+) ions into Ag° was calculated using ICP-AES and was found to be 94%. By calculating flocculation parameter, we could see that these SNPs are extremely stable under the influence of very high NaCl concentration up to 4.16 M. These stable SNPs can be used in various industrial and medical applications.

Biogenic gold nanoparticles as fotillas to fire berberine hydrochloride using folic acid as molecular road map.

Use of biologically modified gold nanoparticles (GNPs) as molecular vehicle to ferry potential anti-cancer drug berberine hydrochloride (BHC) using folic acid (FA) as targeting molecule is reported in this work. A tropical fruit peel, Trapa bispinosa is used to fabricate highly monodispersed GNPs, passivated with essential functional groups which were used as linkers to attach FA and BHC via amide linkage. Flocculation Parameter (FP) of biologically synthesized GNPs was calculated under different salt concentrations which were found to be very ideal under a physiological condition. Various statistical models were used to find drug release profile out of which Higuchi was found to be the most ideal. GNP-FA-BHC complexes were found to be active against folic acid expressing HeLa cells.

Rapid Biosynthesis of Silver Nanoparticles by Exploiting the Reducing Potential of Trapa bispinosa Peel Extract

Present work reports exceptionally high reducing capacity of Trapa bispinosa to synthesize monodispersed silver nanoparticles (SNPs) within 120 seconds at 30°C which is the shortest tenure reported for SNP synthesis using plants. Moreover, we also instigated impact of different pH values on fabrication of SNPs using visible spectroscopy with respect to time. Percentage conversion of Ag

Plasmonic/Magnetic Multifunctional nanoplatform for Cancer Theranostics

A multifunctional magneto-plasmonic CoFe2O4@Au core-shell nanoparticle was developed by iterative-seeding based method. This nanocargo consists of a cobalt ferrite kernel as a core (Nk) and multiple layers of gold as a functionalizable active stratum, (named as Nk@A after fifth iteration). Nk@A helps in augmenting the physiological stability and enhancing surface plasmon resonance (SPR) property. The targeted delivery of Doxorubicin using Nk@A as a nanopayload is demonstrated in this report. The drug release profile followed first order rate kinetics optimally at pH 5.4, which is considered as an endosomal pH of cells. The cellular MR imaging showed that Nk@A is an efficient T2 contrast agent for both L6 (r2-118.08 mM−1s−1) and Hep2 (r2-217.24 mM−1s−1) cells. Microwave based magnetic hyperthermia studies exhibited an augmentation in the temperature due to the transformation of radiation energy into heat at 2.45 GHz. There was an enhancement in cancer cell cytotoxicity when hyperthermia combined with chemotherapy. Hence, this single nanoplatform can deliver 3-pronged theranostic applications viz., targeted drug-delivery, T2 MR imaging and hyperthermia.

Photocatalysis-assisted water filtration: Using TiO2-coated vertically aligned multi-walled carbon nanotube array for removal of Escherichia coli O157:H7

A porous ceramic was coated with vertically aligned multi-walled carbon nanotubes (MWCNTs) by spray pyrolysis. Titanium dioxide (TiO2) nanoparticles were then coated onto this densely aligned MWCNT. The presence of TiO2/MWCNT interfacial arrays was confirmed by X-ray diffraction (XRD), scanning electron microscope-energy dispersive analysis of X-ray (SEM-EDAX) and transmission electron microscope (TEM). This is a novel report in which water loaded with a most dreadful enterohemorrhagic pathogenic strain of Escherichia coli O157:H7 was filtered through TiO2/MWCNT coated porous ceramic filter and then analysed. Bacterial removal performance was found to be significantly lower in control i.e. plain porous ceramic (P<0.05) as compared to TiO2/MWCNT coated ceramic. The photocatalytic killing rate constant for TiO2-ceramic and MWCNT/TiO2-ceramic under fluorescent light was found be 1.45×10(-2) min(-1) and 2.23×10(-2) min(-1) respectively. Further, when I-V characteristics were performed for TiO2/MWCNT composite, it was corroborated that the current under light irradiation is comparatively higher than that in dark, thus proving it to be photocatalytically efficient system. The enhanced photocatalysis may be a contribution of increased surface area and charge transfer rate as a consequence of aligned MWCNT network.

A comparative study of economical separation and aggregation properties of biologically capped and thiol functionalized gold nanoparticles: selecting the eco-friendly trojan horses for biological applications.

We are presenting facile bio-fabrication of extremely stable gold nanoparticles (GNPs) using medicinal plant Azadirachta indica (commonly called Neem) and its comparison with most commonly used glutathione (GSH) protected GNPs in terms of stability under physiological conditions, seperation using density gradient centrifugation and aggregation properties in the solution. There was dual peak at 536 and 662 nm indicating the presence of non-spherical GNPs including triangles, rods and hexagons in case of A. indica mediated GNPs unlike citrate stabilized GNPs which exhibited single sharp peak. Spherical GNPs were separated from the consortium of uniquely shaped nanoparticles bio-fabricated using A. indica leaf extract using sucrose density gradient centrifugation (SDGC).To comprehend the anti-agglomeration potentials of A. indica leaf mediated GNPs and GSH-GNPs under physiological conditions, flocculation parameters (FP) were calculated and found to be least for A. indica leaf mediated GNPs, indicating their exceptional stability.

Cobalt ferrite nanowhiskers as T2 MRI contrast agent

A novel, one-step synthesis of one-dimensional cobalt ferrite nanowhiskers (CfW) is reported. SQUID studies confirmed that the monodispersed surfactant-free CfW exhibit superparamagnetic behaviour. This characteristic makes CfW an ideally suited contrast agent for T2-weighted MRI, thus proving to be very effective for biomedical applications.