Efficacy and reusability of mixed-phase TiO2-ZnO nanocomposites for the removal of estrogenic effects of 17ß-Estradiol and 17α-Ethinylestradiol from water.

Photocatalytic removal of estrogenic compounds (ECs), 17ß-estradiol (E2), and 17α-ethinylestradiol (EE2) were assessed using a TiO2-ZnO nanocomposite (NC) over a range of initial EC concentration (Co; 10 mg/L - 0.05 mg/L). Photocatalytic removal was evaluated under UV and visible irradiation using 10 mg/L NC over 240 min duration. After 240 min, analysis using GCxGC TOF MS revealed 100% transformation at Co ≤ 1 mg/L and ≥25% transformation at Co ≤ 10 mg/L under visible irradiation. Degradation was accompanied by breakdown of the fused ring structure of E2, generating smaller molecular weight by-products which were subsequently mineralized as revealed through TOC removal. With UV photocatalysis, ~30% and ~20% mineralization was attained for E2 and EE2, respectively, for Co of 10 mg/L. Under visible irradiation, ~25% and ~10% mineralization was achieved for E2 and EE2, respectively. Estrogenicity variation was estimated using the E-screen assay conducted with estrogen receptor-positive MCF-7 breast cancer cells. Complete removal of estrogenicity of ECs was confirmed after 240 min of photocatalysis under UV and visible irradiation. FTIR spectroscopy-based analysis of the NC after E2 photocatalysis revealed the presence of sorbed organics. Desorption, followed by GC × GC TOF-MS analysis revealed these organics as by-products of photocatalysis. Desorption of sorbed organics followed by recalcination at 600 °C for 1 h regenerated the active sites on the NC, enabling its efficient reuse for 3 cycles under visible irradiation without loss in activity.

Photocatalytic activity of graphene oxide-TiO2 nanocomposite on dichlorvos and malathion and assessment of toxicity changes due to photodegradation.

Heterogeneous photocatalysis was used for the removal of two widely used organophosphorus pesticides, dichlorvos, and malathion from water. Graphene oxide-TiO2 nanocomposite (GOT) was synthesized and used as a photocatalyst for the removal of these pesticides. Batch studies for optimizing photocatalytic degradation and mineralization of pesticides over 80 min were conducted by varying the pH (2-10), catalyst dose (20 mg/L-200 mg/L), and initial pesticide concentration (0.5 mg/L-20 mg/L), and the irradiation source (125 W UV and visible lamp). Degradation kinetics for the pesticides were evaluated. Ellman assay was used to estimate the toxic effect of pesticides and evaluate toxicity reduction due to treatment. The highest degradation and mineralization of dichlorvos and malathion was observed at pH 6 and the optimum catalyst dose was 60 mg/L. Under UV irradiation, 80% and 90% degradation were observed for dichlorvos and malathion, respectively for 0.5 mg/L initial pesticide concentration. The photocatalytic degradation reaction followed Langmuir-Hinshelwood kinetics. A high degree of mineralization was achieved for both the pesticides. Analysis of the results revealed that the residual toxic effect after photocatalysis was primarily due to the residual parent compound. A comparative study revealed that GOT yielded better pesticide degradation compared to commercially available TiO2 under both UV and visible irradiation.

Enhanced EPR directed and Imaging guided Photothermal Therapy using Vitamin E Modified Toco-Photoxil.

Herein we report synthesis, characterization and preclinical applications of a novel hybrid nanomaterial Toco-Photoxil developed using vitamin E modified gold coated poly (lactic-co-glycolic acid) nanoshells incorporating Pgp inhibitor d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) as a highly inert and disintegrable photothermal therapy (PTT) agent. Toco-Photoxil is highly biocompatible, physiologically stable PTT material with an average diameter of 130 nm that shows good passive accumulation (2.3% ID) in solid tumors when delivered systemically. In comparison to its surface modified counterparts such as IR780-Toco-Photoxil, FA-Toco-Photoxil or FA-IR780-Toco-Photoxil accumulation are merely ~0.3% ID, ~0.025% ID and ~0.005% ID in folate receptor (FR) negative and positive tumor model. Further, Toco-Photoxil variants are prepared by tuning the material absorbance either at 750 nm (narrow) or 915 nm (broad) to study optimal therapeutic efficacy in terms of peak broadness and nanomaterial's concentration. Our findings suggest that Toco-Photoxil tuned at 750 nm absorbance is more efficient (P = 0.0097) in preclinical setting. Toco-Photoxil shows complete passiveness in critical biocompatibility test and reasonable body clearance. High tumor specific accumulation from systemic circulation, strong photothermal conversion and a very safe material property in body physiology makes Toco-Photoxil a superior and powerful PTT agent, which may pave its way for fast track clinical trial in future.

Glycol chitosan assisted in situ reduction of gold on polymeric template for anti-cancer theranostics.

Multifunctional biodegradable nanomaterials that could be used for both imaging and therapy are being researched extensively. A simple technique to synthesize multifunctional nanoparticles without compromising on any of their functionality is a challenge. We have attempted to optimize a two-step procedure of gold coated polymeric template involving 1) Single pot synthesis of PLGA nanoparticles with cationic surface charge using glycol chitosan and 2) in situ gold coating for formation of gold coated PLGA nanoshell (AuPLGA-NS). These gold-coated PLGA nanoparticles were explored for photothermal therapy (PTT) and as X-ray/CT contrast agents. Biocompatibility and photothermal cytotoxicity of AuPLGA-NS were evaluated in-vitro and results confirmed the therapeutic efficacy of these particles resulting in 80% cancer cell death. Besides, it also showed potential X-ray/CT imaging ability with contrast equivalent to that of Iodine. The results demonstrated that these gold-coated PLGA nanoparticles synthesized by a simple approach could be used as a multifunctional nanosystem for cancer theranostics.

A therapeutic polyelectrolyte-vitamin C nanoparticulate system in polyvinyl alcohol-alginate hydrogel: An approach to treat skin and soft tissue infections caused by Staphylococcus aureus.

Staphylococcus aureus infections affecting the skin and soft tissues are of significant health concern and an unmet need to be addressed. The lack of drug penetration into the infectious site is the main clinical challenge. Once the pathogen invades the wounded skin, it attenuates biological response pathways, leading to chronic infection. Wound infections are associated with alkaline pH due to the presence of bacteria, whereas creation of an acidic environment around the wound bed promotes faster healing. Herein, we develop injectable drug loaded nanoparticulate system of vancomycin encapsulated polycaprolactone nanoparticles coated with polyelectrolyte-Vitamin C in polyvinyl alcohol-alginate gel (D-PCL-PVc-PVA(Alg). The nanoparticles were synthesized via emulsion solvent evaporation method with polyallylamine hydrochloride-vitamin C coating, had a size of ∼35.93±3.00nm and improved stability of -34.5±6mV. PVA-Alginate gel served as a carrier, wherein the nanoparticles created an acidic environment pH (5-6), exhibiting a strong anti-staphylococcal activity (fivefold) when compared with the widely used antibiotic vancomycin. Ex-vivo permeation studies and imaging revealed that D-PCL-PVc-PVA(Alg), when injected, goes deep to the infectious crevices, destroying S.aureus completely with sustained drug release through diffusion with utmost biocompatibility towards L929 cells. This work substantiates use of D-PCL-PVc-PVA(Alg) for skin and soft tissue infections (SSTI).