Ultrasensitive Electrochemical Aptasensing of Malathion Based on Hydroxylated Black Phosphorus/Poly-L-Lysine Composite.

A highly sensitive unlabeled electrochemical aptasensor based on hydroxylated black phosphorus/poly-L-lysine (hBP/PLL) composite is introduced herein for the detection of malathion. Poly-L-lysine (PLL) with adhesion and coating properties adhere to the surface of the nanosheets by noncovalent interactions with underlying hydroxylated black phosphorus nanosheets (hBP) to produce the hBP/PLL composite. The as-synthesized hBP/PLL composite bonded to Au nanoparticles (Au NPs) firmly by assembling and using them as a substrate for the aptamer with high specificity as a probe to fabricate the sensor. Under optimal conditions, the linear range of the electrochemical aptasensor was 0.1 pM~1 µM, and the detection limit was 2.805 fM. The electrochemical aptasensor has great selectivity, a low detection limit, and anti-interference, which has potential application prospects in the field of rapid trace detection of pesticide residues.

Preparation of pyrolysis products by catalytic pyrolysis of poplar: Application of biochar in antibiotic wastewater treatment.

Poplar waste is acted as feedstock to produce renewable biofuel and green chemical by catalytic pyrolysis using ferric nitrate and zinc chloride as additive. The additive contributes to the generation of furfural in bio-oil. Additive promotes the generation of H2 and inhibits the generation of CO with bio-gas heating value of 12.16 MJ (Nm3)-1. Biochar exists ZnO and Fe3O4 with large surface area, which could be used as absorbent and photocatalyst for tetracycline and ciprofloxacin removal. The tetracycline and ciprofloxacin adsorption amount of biochar are 316.41 and 255.23 mg g-1 respectively. While the photocatalytic degradation removal of the tetracycline and ciprofloxacin is close to 100%. The adsorption and photocatalytic degradation mechanism are investigate and analyzed using the density functional theory and electron paramagnetic resonance analysis. Biochar can be quickly recycled and regenerated after use. Besides, biochar can be used in lithium ion battery industry for energy storage, which specific capacity is 535 mAh g-1.

Fixating lead in coal gangue with phosphate using phosphate-dissolving bacteria: Phosphorus dissolving characteristics of bacteria and adsorption mechanism of extracellular polymer.

Controlling and preventing lead pollution is currently the focus of environmental remediation. Coal gangue contains large quantities of lead, and its environmental impact cannot be ignored. This study investigated the tolerance of Stenotrophomonas maltophilia (YZ-1 train) to lead ion and its fixation effect on lead in coal gangue. The fixation mechanism of lead ions by using the YZ-1 train was studied with CaHPO4 and Ca3(PO4)2. The tolerance mechanism and fixation characteristics of the three bacterial extracellular polymers and cell components to lead were analyzed. The results show that the YZ-1 train had a strong resistance to lead ions. The amount of lead released from coal gangue can be reduced by up to 91.1% upon treatment with the YZ-1 train, which can dissolve phosphate minerals to form stable hydroxyapatite (Pb5(PO4)3(OH)) and pyromorphite (Pb5(PO4)3Cl) with lead ions. Tryptophan and tyrosine from cellular components and extracellular polymers with loosely and tightly bound proteins are the main participants in the fixation of lead ions. The by-products of soluble microbes affect the fixation of lead ions in soluble extracellular polymers. The carboxylic acids and carboxylates secreted by bacteria are involved in the adsorption and fixation of lead ions.

Neuroprotective effects of PRG on Aß25-35-induced cytotoxicity through activation of the ERK1/2 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Phylloporia ribis (Schumach:Fr.)Ryvarden is a genus of needle Phellinus medicinal fungi, parasitic on the living rhizomes of hawthorn and pear trees. As a traditional Chinese medicine, Phylloporia ribis was used in folklore for long-term illness, weakness and memory loss in old age. Previous studies have shown that polysaccharides from Phylloporia ribis (PRG) significantly promoted synaptic growth in PC12 cells in a dose-dependent manner, exhibiting "NGF"-like neurotrophic activity. Aß25-35 damage to PC12 cells produced neurotoxicity and decreased cell survival, and PRG reduced the apoptosis rate, suggesting that PRG has neuroprotective effects. The studies confirmed that PRG had the potential to be a neuroprotective agent, but its neuroprotective mechanism remained unclear. AIM OF THE STUDY: We aimed to elucidate the neuroprotective effects of PRG in an Aß25-35-induced Alzheimer's disease (AD) model. MATERIALS AND METHODS: Highly-differentiated PC12 cells were treated with Aß25-35 (AD model) and PRG, and were assessed for cellular apoptosis, inflammatory factors, oxidative stress, and kinase phosphorylation. RESULTS: The results showed that the PRG groups effectively inhibited the neurotoxicity, mainly manifested by inhibiting mitochondrial oxidative stress, attenuating neuroinflammatory responses, and improving mitochondrial energy metabolism, eventually resulting in higher cell survival. The expression of p-ERK, p-CREB and BDNF proteins was increased in the PRG groups compared to the model group, which confirmed that PRG reversed the inhibition of the ERK pathway. CONCLUSION: We provide evidence for neuroprotection conferred by PRG and its mechanism by inhibiting ERK1/2 hyper-phosphorylation, prevention of mitochondrial stress, and subsequent prevention of apoptosis. The study highlights PRG as a promising candidate with neuroprotective effects, the potential of which can be harnessed for identifying novel therapeutic targets.

Label-Free Aptasensor for Detection of Fipronil Based on Black Phosphorus Nanosheets.

A label-free fipronil aptasensor was built based on Polylysine-black phosphorus nanosheets composition (PLL-BPNSs) and Au nanoparticles (AuNPs). A PLL-BP modified glassy carbon electrode (GCE) was fabricated by combining BP NSs and PLL, which included a considerable quantity of -NH2. Au nanoparticles (AuNPs) were placed onto the GCE, and PLL-BPNSs bonded to Au NPs firmly by assembling. The thiolated primers were then added and fixed using an S-Au bond, and competitive binding of the fipronil aptamer was utilized for fipronil quantitative assessment. The sensor's performance was evaluated using differential pulse voltammetry (DPV) method. The linear equation is ΔI (µA) = 13.04 logC + 22.35, while linear correlation coefficient R2 is 0.998, and detection limit is 74 pg/mL (0.17 nM) when the concentration of fipronil is 0.1 ng/mL-10 µg/mL. This aptasensor can apply to quantitative detection of fipronil.

Recent Progress in Black Phosphorus Sensors.

Black phosphorus (BP) is a new two-dimensional material with many unique properties, such as great biocompatibility, excellent surface activity, high carrier mobility, and tunable bandgap. Black phosphorus has been particularly attractive in sensor. However, black phosphorus isolated by traditional methods is easily oxidized and degraded by air, with poor stability, which limits its application as sensors. The modification and functionalization of black phosphorus enhance the stability, sensitivity, selectivity and biocompatibility of its application in sensor. This review describes recent progresses in sensor based on black phosphorus (2016-2020). Firstly, the structure and properties, synthesis methods, modification and functionalization of black phosphorus are briefly described. Then, the advancements in designing of various sensors based on black phosphorus are systematically provided, with a specific focus on electrochemical sensors, electrochemiluminescence sensors and photoelectrochemical sensors. Finally, latest challenges and further opportunities for developing new sensors with black phosphorus nanomaterial are discussed.

A Novel Strategy for Liquid Exfoliation of Ultrathin Black Phosphorus Nanosheets.

As an emerging two-dimensional layered material, black phosphorus nanosheets show unparalleled optical and electronic properties. Although black phosphorus nanosheets have attracted much attention in the photoelectric field, their applications in biomedical field were still limited due to their poor biocompatibility of current synthesis strategies. Herein, we propose a novel synthetic strategy for black phosphorus nanosheets that rely on Tween 20-assisted liquid exfoliation and post-processing in deoxygenated water. Microscopic and spectroscopic analysis suggested that the produced black phosphorus nanosheets dispersions exhibited good stability and higher yield compared with other currently prepared methods. Because of their ultrahigh exfoliation efficiency, the black phosphorus flakes present few-layer and even monolayer, which are thinner than the most dispersions of black phosphorus. Thus, this method enables mass-production of high-quality few-layer black phosphorus with high biocompatibility, and has the potential to be directly used in the biological field.