Distribution and migration of uranium, chromium, and accompanying metal(loid)s in soil-plants system around a uranium hydrometallurgical area.

The extraction and utilization of uranium (U) ores have led to the release of significant amounts of potentially toxic metal(loid)s (PTMs) into the environment, constituting a grave threat to the ecosystem. However, research on the distribution and migration mechanism of U, chromium (Cr), and their accompanying PTMs in soil-plant system around U hydrometallurgical area remains insufficient and poorly understood. Herein, the distribution, migration, and risk level of PTMs were evaluated in soil and plant samples around U hydrometallurgical area, Northern Guangdong, China. The results demonstrated that the maximum content of U and Cr found in the analyzed soils were up to 84.2 and 238.9 mg/kg, respectively. These values far exceed the soil background values in China and other countries. The highest content of U (53.6 mg/kg) was detected in Colocasia antiquorum Schott, and the highest content of Cr (349.5 mg/kg) was observed in Pteridium aquilinum, both of which were enriched in their roots. The risk assessment of PTMs demonstrated that the study area suffered from severe pollution (PN > 3), especially from U, Cr, Th, and As, suggesting the non-negligible anthropogenic impacts. Hence, in light of the significant ecological hazard posed by the U hydrometallurgical area, it is imperative to implement appropriate restoration measures to ensure the human health and maintain the stability of the ecosystem.

A biodegradable chitosan-based polymer for sustained nutrient release to stimulate groundwater hydrocarbon-degrading microflora.

Petroleum hydrocarbon-contaminated groundwater often has a low indigenous microorganism population and lacks the necessary nutrient substrates for biodegradation reaction, resulting in a weak natural remediation ability within the groundwater ecosystem. In this paper, we utilized the principle of petroleum hydrocarbon degradation by microorganisms to identify effective nutrients (NaH2PO4, K2HPO4, NH4NO3, CaCl2, MgSO4·7H2O, FeSO4·7H2O, and VB12) and optimize nutrient substrate allocation through a combination of actual surveys of petroleum hydrocarbon-contaminated sites and microcosm experiments. Building on this, combining biostimulation and controlled-release technology, we developed a biodegradable chitosan-based encapsulated targeted biostimulant (i.e., YZ-1) characterized by easy uptake, good stability, controllable slow-release migration, and longevity to stimulate indigenous microflora in groundwater to efficiently degrade petroleum hydrocarbon. Results showed that YZ-1 extended the active duration of nutrient components by 5-6 times, with a sustainable release time exceeding 2 months. Under YZ-1 stimulation, microorganisms grew rapidly, increasing the degradation rate of petroleum hydrocarbon (10 mg L-1) by indigenous microorganisms from 43.03% to 79.80% within 7 d. YZ-1 can easily adapt to varying concentrations of petroleum hydrocarbon-contaminated groundwater. Specifically, in the range of 2-20 mg L-1 of petroleum hydrocarbon, the indigenous microflora was able to degrade 71.73-80.54% of the petroleum hydrocarbon within a mere 7 d. YZ-1 injection facilitated the delivery of nutrient components into the underground environment, improved the conversion ability of inorganic electron donors/receptors in the indigenous microbial community system, and strengthened the co-metabolism mechanism among microorganisms, achieving the goal of efficient petroleum hydrocarbon degradation.

Electrostimulus-triggered reactive oxygen species level in organelles revealed by organelle-targeting SERS nanoprobes.

Electrostimulation (ES) is an important therapeutic method for diseases caused by abnormal intracellular electrical activity. Also, it can induce apoptosis of cells, which is a potential tumor treatment method. At present, there are no relevant studies on changes in intracellular reactive oxygen species (ROS) levels produced in the process of ES, or on the effects of simultaneous implementation of conventional antioxidant inhibitor drugs and ES therapy. To reveal these, two organelle-targeting core-shell plasmonic probes were designed for measuring ROS produced during ES. The probes were delivered into target organelles (nucleus and mitochondrion) before the cells were electrically stimulated for different periods of time. Surface-enhanced Raman scattering (SERS) signals were detected in situ, and the sensing mechanism for the quantitative analysis of ROS is based on the signal reduction of SERS caused by the ROS-etching effect on the silver shell. The detection results revealed that ES could trigger ROS generation in cells, and the ROS levels localized around organelles were assessed by SERS. This study has great potential for exploring abnormal organelle microenvironments via organelle-targeting probes combined with SERS technology.

Electrostimulus-associated PD-L1 expression on cell membrane revealed by immune SERS nanoprobes.

Programmed cell death ligand 1 (PD-L1) is considered a major immune checkpoint protein that mediates antitumor immune suppression and response. Effectively regulating PD-L1 expression and dynamic monitoring has become a significant challenge in immunotherapy. Herein, we adopted smart surface-enhanced Raman scattering (SERS) nanoprobes to discriminate and monitor the dynamic expression of PD-L1 under external electrostimulation (ES). The PD-L1 expression levels in three cell lines (MCF-7 cells, HeLa cells, and H8 cells) were assessed before and after ES. The results reveal that ES could effectively and rapidly mediate a transformation in the PD-L1 content (or activity) on the cell membrane. Moreover, the molecular profiles of the cell membrane before and after ES were revealed by using the label-free SERS method with the help of immune plasmonic nanoparticles. The cell membrane protein information presented identifiable conformation changes after ES, showing a significant inhibitory effect on the bridge of PD-L1 and its antibody. This study indicates that ES is superior to chemical drugs due to lesser side effects because ES-based regulation does not depend on intracellular signalling pathways. This strategy is versatile and robust for discriminating and monitoring PD-L1 on cell membranes, thus providing potential clinical application value to PD-L1-mediated systems. This study also offers a practical way to assess the molecular profiles of cell membrane proteins in the presence of an external stimulus, which may be applicable to many membrane protein-related studies.

Ultrasensitive detection of trypsin in serum via nanochannel device.

A highly sensitive trypsin sensing system in serum was developed by using an anodic alumina oxide (AAO)-based, trypsin substrate-decorated hybrid ion permeation membrane. Owing to the trypsin-triggered peptide hydrolyzation reaction, the surface electrical feature of the peptide-decorated hybrid ion membrane changed. The electric double layer effect reduces the effective ion current diameter in the AAO nano unit, so that the ion current rectification ratio will be enhanced, realizing the quantitative detection of trypsin. The lowest detection concentration can be achieved as low as 0.1 pM. This method is no need for sample pre-preparation, easy to operate, highly sensitive, and also applicable to other enzyme evaluation systems by changing corresponding substrates. This study provides a new idea for selective measurements of proteases in complex biological samples.

Intracellular pH-propelled assembly of smart carbon nanodots and selective photothermal therapy for cancer cells.

A kind of smart carbon nanodots (CNDs) with the pH response feature was prepared by the one-pot hydrothermal treatment of citric acid and dicyandiamide, which was used for the differentiation of cancer/normal cells and the selective photothermal therapy (PTT) of cancer cells. When the smart CNDs were cultured with cells, they were highly internalized in the lysosomes of cells. Since the small-sized CNDs (about 5 nm) tends to form aggregation (as large as about 20 nm or even larger) under an acid condition (pH = 4.7) due to the electrostatic attraction produced by the surface protonation, relatively severer aggregation of the CNDs were observed in liver cancer cells (HepG2 cells) relative to normal ones (LO2 cells) due to a relative lower pH in the lysosomes of HepG2 cells, which endows them a new strong absorption band at longer wavelengths (450-900 nm) and a higher photothermal conversion efficiency (42.13 %), benefiting to differentiated PTT. The flow cytometric data indicates strong photothermal ablation (8 min, 509.6 mW/cm2) for cancer cells with the assistance of these smart CNDs achieves 82 % death rate of cancer cells, while much less damage is observed on the normal cells (6.35 %). To the best of our knowledge, this is the first report about CNDs for selective PTT owing to their intrinsic property without the aid of any other targeting ligands. These smart CNDs are also available for other acid-responsive sensing systems, and this study inspires us in the synthesis of near-infrared featured carbon materials.

Tracing the molecular dynamics of living mitochondria under phototherapy via surface-enhanced Raman scattering spectroscopy.

Subcellular mitochondrion has become a target for improving the therapeutic efficiency and reducing side damage to normal cells via a combination of many therapeutic strategies. However, the underlying molecular mechanisms associated with cell death induced by subcellular dysfunction remain unknown or disputed. In this study, we investigated the dynamic molecular changes of living mitochondria upon phototherapy (photothermal therapy plus photodynamic therapy, PTT & PDT) by surface-enhanced Raman scattering spectroscopy (SERS) and intended to disclose the photo-induced cell death route in breast cancer cells (MCF-7) taking into account the mitochondrion. Indocyanine green (ICG), a Food and Drug Administration (FDA)-approved clinic blood-injection near-infrared angiographic contrast agent and a PTT & PDT drug, was used for the evaluation of the phototherapy effect. The results revealed that the content of phenylalanine (Phe) in mitochondria evidently increased during the phototherapy-induced cell death process. Moreover, the phototherapy-induced cell apoptosis was mainly regulated through the DNA structures. We expect that the understanding of mitochondrial molecular stress responses will be helpful for the diagnosis and therapy of cellular processes associated with mitochondria and provide valuable guidance for the further design and development of more effective therapeutic platforms and methods at the sub-cellular level.

Living-Cell Imaging of Mitochondrial Membrane Potential Oscillation and Phenylalanine Metabolism Modulation during Periodic Electrostimulus.

Special electrosensory cells are sensitive to electric fields and give responses upon stimulation, but little is known about normal regular cells and cancerous cells. Herein, by designing nucleus- and mitochondria-targeting SERS nanoprobes combined with fluorescent monitoring of the mitochondrial membrane potential (MMP) variations, we found an interesting electrosensory and self-healing response in MMP within cancerous and normal cells during periodic impulse electrostimulation (IES). More importantly, the key regulator role of phenylalanine (phe) was revealed by cell fluorescent imaging and SERS detection, whose expression level was increased in response to IES to induce cell apoptosis. During IES off-state, the self-repair function of cells was activated to reduce phe release. We also found that cancerous cells (MCF-7 and HeLa cells) demonstrated a response more remarkable than that of normal cells (L929 and H8 cells) to periodic IES. Our finding revealed a common electrosensory and self-repair biofunction of cells and its related phe metabolism response. Understanding the difference of biophysical/electrophysiological responses between cancerous and normal cells may broaden the view for cancer therapy in the future.

Aptamer-based surface-enhanced Raman scattering-microfluidic sensor for sensitive and selective polychlorinated biphenyls detection.

A surface-enhanced Raman scattering (SERS) measurement of 3,3',4,4'-tetrachlorobiphenyl (PCB77) with aptamer capturing in a microfluidic device was demonstrated. To construct the microfluidic chip, an ordered Ag nanocrown array was fabricated over a patterned polydimethylsiloxane (PDMS) that was achieved by replicating an anodic aluminum oxide (AAO) template. The patterned PDMS sheet was covered with another PDMS sheet having two input channel grooves to form a close chip. The Ag nanocrown array was used for the SERS enhancement area and the detection zone. PCB 77 aptamers were injected into one channel and the other allows for analytes (PCBs). The mercapto aptamers captured the targets in the mixed zone and were immobilized to the SERS detection zone via S-Ag bonds so as to further improve both the SERS sensitivity and selectivity of PCB77. Such an aptamer-based microfluidic chip realized a rapid SERS detection. The lowest detectable concentration of 1.0 × 10(-8) M was achieved for PCB77. This work demonstrates that the aptamer-modified SERS microfluidic sensor can be utilized for selective detections of organic pollutants in the environment.

Microbial community study in newly established Qingcaosha Reservoir of Shanghai, China.

Qingcaosha Reservoir located at Yangtze Estuary of China is a newly constructed and one of the largest tidal reservoirs in the world, which will be an important drinking water source of Shanghai. This study aims at investigating microbial community and its shifts corresponding to different water quality during the test running period of Qingcaosha Reservoir. The results showed lower concentrations of total nitrogen (TN) and total phosphorus (TP) in the reservoir than that in Yangtze Estuary. The number of total cultivable bacteria was significantly lower in the reservoir than that of Yangtze Estuary. The denaturing gradient gel electrophoresis (DGGE) analysis showed that the dominant microbes were α-Proteobacteria, ß-Proteobacteria, Flavobacterium, Rheinheimera, Prochlorococcus, and Synechococcus. The quantitative PCR (q-PCR) results revealed significantly higher number of cyanobacteria and Microcystis in the reservoir during summer season. In addition, bacterial abundance positively correlated with TP concentration inside the reservoir. These results indicated that Qingcaosha Reservoir had ability to reduce the TN and TP in influent and improve the water quality overall. However, it also faced the risk of potential cyanobacteria bloom and eutrophication in Qingcaosha Reservoir where phosphorus will be the nutrient limiting factor.

The use of Au@SiO2 shell-isolated nanoparticle-enhanced Raman spectroscopy for human breast cancer detection.

This study uses the powerful fingerprint features of Raman spectroscopy to distinguish different types of breast tissues including normal breast tissues (NB), fibroadenoma (FD), atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS), and invasive ductal carcinoma (IDC). Thin frozen tissue sections of fresh breast tissues were measured by Raman spectroscopy. Due to the inherent low sensitivity of Raman spectra, Au@SiO2 shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) technique was utilized to provide supplementary and more informative spectral features. A total of 619 Raman spectra were acquired and compared to 654 SHINERS spectra. The maximum enhancement effect of distinct and specific bands was characterized for different tissue types. When applying the new criteria, excellent separation of FD, DCIS, and IDC was obtained for all tissue types. Most importantly, we were able to distinguish ADH from DCIS. Although only a preliminary distinction was characterized between ADH and NB, the results provided a good foundation of criteria to further discriminate ADH from NB and shed more light toward a better understanding of the mechanism of ADH formation. This is the first report to detect the premalignant (ADH and DCIS) breast tissue frozen sections and also the first report exploiting SHINERS to detect and distinguish breast tissues. The results presented in this study show that SHINERS can be applied to accurately and efficiently identify breast lesions. Further, the spectra can be acquired in a minimally invasive procedure and analyzed rapidly facilitating early and accurate diagnosis in vivo/in situ.

Immunoassay using probe-labelling immunogold nanoparticles with silver staining enhancement via surface-enhanced Raman scattering.

This paper reports a novel immunoassay based on surface-enhanced Raman scattering (SERS) and immunogold labelling with silver staining enhancement. Immunoreactions between immunogold colloids modified by a Raman-active probe molecule (e.g., 4-mercaptobenzoic acid) and antigens, which were captured by antibody-assembled chips such as silicon or quartz, were detected via SERS signals of Raman-active probe molecule. All the self-assembled steps were subjected to the measurements of ultraviolet-visible (UV-vis) spectra to monitor the formation of a sandwich structure onto a substrate. The immunoassay was performed by a sandwich structure consisting of three layers. The first layer was composed of immobilized antibody molecules of mouse polyclonal antibody against Hepatitis B virus surface antigen (PAb) on a silicon or quartz substrate. The second layer was the complementary Hepatitis B virus surface antigen (Antigen) molecules captured by PAb on the substrate. The third layer was composed of the probe-labelling immunogold nanoparticles, which were modified by mouse monoclonal antibody against Hepatitis B virus surface antigen (MAb) and 4-mercaptobenzoic acid (MBA) as the Raman-active probe on the surface of gold colloids. After silver staining enhancement, the antigen is identified by a SERS spectrum of MBA. A working curve of the intensity of a SERS signal at 1585 cm(-1) due to the [small nu](8a) aromatic ring vibration of MBA versus the concentration of analyte (Antigen) was obtained and the non-optimized detection limit for the Hepatitis B virus surface antigen was found to be as low as 0.5 [micro sign]g mL(-1).