Sequential photo electro oxidation and biodegradation of textile effluent: Elucidation of degradation mechanism and bacterial diversity.

Textile effluent contains a highly toxic and refractory azo dyes. Eco-friendly method for efficient decolorization and degradation of textile effluent is essential. In the present study, treatment of textile effluent was carried through sequential electro oxidation (EO) and photo electro oxidation (PEO) using RuO2-IrO2 coated titanium electrode as an anode and cathode followed by biodegradation. The pre-treatment of textile effluent by photo electro oxidation for 14 h exhibited 92% of decolorization. Subsequent biodegradation of the pre-treated textile effluent enhanced the reduction of chemical oxygen demand to 90%. Metagenomics results exhibited that Flavobacterium, Dietzia, Curtobacterium, Mesorhizobium, Sphingobium, Streptococcus, Enterococcus, Prevotellaand Stenotrophomonas bacterial communities majorly involved in the biodegradation of textile effluent. Hence, integrating sequential photo electro oxidation and biodegradation proposed an efficient and eco-friendly approach for treating textile effluent.

Remarkably Efficient Blood-Brain Barrier Crossing Polyfluorene-Chitosan Nanoparticle Selectively Tweaks Amyloid Oligomer in Cerebrospinal Fluid and Aß1-40.

Amyloid oligomers have emerged as a key neurotoxin in Alzheimer's dementia. Amyloid aggregation inhibitors and modulators have therefore offered potential applications in therapeutics and diagnosis. However, crossing the blood-brain barrier (BBB) and finding the toxic aggregates among aggregates of different sizes and shapes remain a challenge. The ability of identifying early aggregates can provide a new approach to find inhibitors of the initial nucleation events correlating presenile dementia. In this study, we have prepared polyfluorene nanoparticles using chitosan as an additive, which enables it to cross BBB efficiently and employed as a highly efficient amyloid oligomer modulator. The polymer conjugate, polyfluorene-chitosan (PC), shows no toxicity in MTT assay and precludes self-aggregation of Aß1-40 and human cerebrospinal fluid oligomers to final fibril formation. This modulation strategy is supported by thioflavin T assay, circular dichroism studies, atomic force microscope images, and Fourier transform infrared analysis. The polymer-protein interface exhibits the presence of co-aggregates and responded with a stable optical response. The simple synthesis to get desired sizes and shapes with necessary photophysical behavior, biocompatibility, and most prominently BBB permeability makes this polymer conjugate very unique and highly attractive for modulation of amyloid oligomers selectively as well as for developing next generation nanotheranostic materials toward presenile dementia.

Amplified Fluorescence from Polyfluorene Nanoparticles with Dual State Emission and Aggregation Caused Red Shifted Emission for Live Cell Imaging and Cancer Theranostics.

A newly synthesized polyfluorene derivative with pendant di(2-picolyl)amine (PF-DPA) shows dual state emission and aggregation caused red shifted emission that was utilized for cell imaging and cancer theranostics. PF-DPA was nontoxic to normal cells but showed cytotoxicity against cancer cells, suggesting its utility for cancer therapy. PF-DPA exhibits a large and unique red shifted emission at 556 nm at higher water ratio of THF:H2O (10:90) due to the formation of polymer nanoparticles or PDots spontaneously by intra- and intermolecular self-assembly induced aggregation. Dual state emission and aggregation caused red shifted emission (>100 nm) in PF-DPA homopolymer nanoparticles is very unique and attributed to the combined effect of intramolecular planarization and J-type aggregate formation in the PDots (25 ± 5 nm). The PF-DPA PDots exhibit bright green and orange fluorescence with exceptional live cell imaging properties and potential applications in cancer theranostics due to their selective cytotoxic nature toward cancer cells.

Modulation of Amyloid Aggregates into Nontoxic Coaggregates by Hydroxyquinoline Appended Polyfluorene.

Inhibitory modulation toward de novo protein aggregation is likely to be a vital and promising therapeutic strategy for understanding the molecular etiology of amyloid related diseases such as Alzheimer's disease (AD). The building up of toxic oligomeric and fibrillar amyloid aggregates in the brain plays host to a downstream of events, causing damage to axons, dendrites, synapses, signaling, transmission, and finally cell death. Herein, we introduce a novel conjugated polymer (CP), hydroxyquinoline appended polyfluorene (PF-HQ), which has a typical "amyloid like" surface motif and exhibits inhibitory modulation effect on amyloid ß (Aß) aggregation. We delineate inhibitory effects of PF-HQ based on Thioflavin T (ThT) fluorescence, atomic force microscopy (AFM), circular dichroism (CD), and Fourier transform infrared (FTIR) studies. The amyloid-like PF-HQ forms nano coaggregates by templating with toxic amyloid intermediates and displays improved inhibitory impacts toward Aß fibrillation and diminishes amyloid cytotoxicity. We have developed a CP based modulation strategy for the first time, which demonstrates beneficiary amyloid-like surface motif to interact efficiently with the protein, the pendant side groups to trap the toxic amyloid intermediates as well as optical signal to acquire the mechanistic insight.

Modulation of Amyloid-ß Fibrils into Mature Microrod-Shaped Structure by Histidine Functionalized Water-Soluble Perylene Diimide.

Alzheimer's disease (AD) is associated with different types of amyloid peptide aggregates including senile plaques, fibrils, protofibrils, and oligomers. Due to these difficulties, a powerful strategy is needed for the disaggregation of amyloid aggregates by modulating their self-aggregation behavior. Herein, we report a unique approach toward transforming the aggregated amyloidogenic peptides using an amino acid functionalized perylene diimide as a molecular modulator, which is a different nondestructive approach as compared to inhibiting the aggregation of peptides. The histidine functionalized perylenediimide (PDI-HIS) molecule could coassemble with amyloid ß (Aß) peptides via hydrogen bonding that leads to the enhancement in the π-π interactions between Aß and PDI-HIS moieties. The Thioflavin T (ThT) assay and various spectroscopic and microscopic techniques establish that the PDI-HIS molecules accelerate the Aß1-40 and the amyloid aggregates in CSF into micro size coassembled structures. These results give rise to a new and unique complementary approach for modulating the biological effects of the aggregates in amyloidogenic peptides.

Highly selective probe detects Cu2+ and endogenous NO gas in living cell.

The rapid and highly sensitive detection of extremely short-lived nitric oxide (NO) gas generated in vivo by a water-soluble fluorescein derivative is developed. This assay system comprises of indole-3-carboxaldehyde functionalized fluorescein hydrazone (FI) assay which displays a typically high absorption at 492 and 620 nm in the presence of Cu2+ and also shows FRET induced fluorescence turn-on exclusively with Cu2+. FI selectively detects Cu2+ in vivo and in vitro by the "turn-on" mechanism followed by fluorescence "turn-off" with NO gas generated by the lipopolysaccharide (LPS) action. The in vivo experiment performed in the cellular system indicates that FI loaded RAW264.7 cells showed bright fluorescence in the presence of Cu2+, while other metals did not influence the FI fluorescence. In addition, the fluorescence of FI-Cu2+ was efficiently quenched by NO generated in macrophages through LPS stimulation. FI demonstrates characteristic "turn-on" behavior in the presence of Cu2+ via spirolactom ring-opening, while other metals such as Na+, K+, Ca2+, Cr3+, Mn2+, Fe3+, Fe2+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+, and Ag+ did not influence FI fluorescence even at very high concentration. Further, the FI-Cu2+ complex fluorescence was not quenched with any anions or amino acids but totally quenched by NO and the paramagnetic nature of Cu2+ ion converted into the diamagnetic nature when reduced to Cu1+. FI and the FI-Cu2+ complex are nontoxic to the cellular system and have high potential for biomedical applications.