Spatiotemporal based response for methylene blue removal using surface modified calcium carbonate microspheres coated with Bacillus sp.

Calcium carbonate microspheres are attractive for their biocompatibility, high loading capacity and easy preparation. They can be used in biomedicine and catalytic applications. In the present work, calcium carbonate microspheres were surface modified with polyvinylpyrrolidone (PVP) followed by irradiation at 5 kGy prior to coating with Bacillus sp. cells. To provide cell protection and internal energy storage, polyhydroxybutyrate (PHB) was induced using 3 factors 2 levels factorial design where the order of effect on PHB% was pH > incubation time > glucose concentration. The highest production was 81.68 PHB% at pH 9, 20 g L-1 glucose and 4 days incubation time. Bacillus sp. cells grown under PHB optimal conditions were used to coat the surface modified calcium carbonate microspheres. Characterization was performed using X-ray diffraction, Fourier Transform Infrared Spectroscopy, Dynamic light Scattering, Zeta potential and Scanning Electron Microscopy. The results obtained confirm the formation and coating of microspheres of 2.34 µm and -16 mV. The prepared microspheres were used in bioremoval of methylene blue dye, the results showed spatiotemporal response for MB-microsphere interaction, where PHB induced Bacillus sp. coated microspheres initially adsorb MB to its outer surface within 1 h but decolorization takes place when the incubation time extends to 18 h. The microspheres can be reused up to 3 times with the same efficiency and with no desorption. These results suggest that the surface modified calcium carbonate can be tailored according to the requirement which can be delivery of biomaterial, bioadsorption or bioremediation.

Tailoring of chitosan/diacrylated pluronic system as a versatile nanoplatform for the amelioration of radiation-induced cognitive dysfunction.

Rutin (RUT) is a biologically active flavonoid that is reported to modulate radiation-induced brain dysfunctions. However, RUT's poor water solubility and low brain bioavailability limit its clinical use. To increase its brain bioavailability, RUT was loaded onto nanoplatforms based on chitosan/diacrylated pluronic (CS/DA-PLUR) nanogels synthesized by gamma radiation. The optimized formulation was investigated as a carrier system for RUT. Based on pilot experiments' results, the cranial radiation (CR) dose that induced cognitive dysfunction was selected. In the main experiment, rats were pre-treated orally with either free RUT or RUT-CS/DA-PLUR. Rats' cognitive and motor functions were assessed; 24 h later, rats were sacrificed, and the whole brain was separated for histopathological examination and biochemical estimation of brain content of acetylcholine esterase (AChE), neurotransmitters, oxidative stress markers, and interleukin-1ß. CR produced prominent impairment in spatial and non-spatial learning memory, motor coordination, and muscular strength. Moreover, histopathological and biochemical alterations in brain contents of neurotransmitters, oxidative stress, and interleukin-1ß were induced by CR. Conversely, RUT-CS/DA-PLUR, but not free RUT, successfully guarded against all the detrimental effects induced by CR. Based on the current findings, loading of RUT enhanced its bioavailability and therapeutic effectiveness by restoring the cognitive functions impaired by CR.

Environmentally benign hybrid nanocomposite beads for azo dye remediation via synchronized dual degradation mechanisms.

Practically, 12% of used dyes are excluded as waste in the mobile aqueous environment. Methyl orange (MO), an industrial azo dye, is known to be carcinogenic. Accordingly, this work was engaged to fabrication of a high-efficiency visible light photocatalysts based on Ag-Alginate/Chitosan-coated MgO nanocomposite beads. MgO and Ag were prepared via precipitation and γ-radiation reduction technique as a green physical one, respectively. The degradation mechanisms depended on catalytic reduction by means of sodium borohydride/Ag and photooxidative degradation. XRD proved the periclase crystalline form of MgO of size 20 nm and the formation of face-centered cubic silver crystals of size 15 nm. The degradation yield varied directly with time, MgO, and dye concentration until certain limit. Five and twenty minutes were enough to get clear solution of MO (30 and 15 ppm, respectively) while 60 min was required to achieve the same target for 60 ppm MO solution. The catalysts showed high efficiency for MO of high concentration. The incorporation of Ag into catalytic beads could support both mechanisms as it could elevate the degradation efficiency up to 50% and save the time to a great extent. Thus, this carrier fruitfully converted wastewater into an effluent that can be repaid to the water cycle with minimal strike on the ecosystem.