Sensitive and reliable lab-on-paper biosensor for label-free detection of exosomes by electrochemical impedance spectroscopy.

A new, sensitive, and cost-effective lab-on-paper-based immunosensor was designed based on electrochemical impedance spectroscopy (EIS) for the detection of exosomes. EIS was selected as the determination method since there was a surface blockage in electron transfer by binding the exosomes to the transducer. Briefly, the carbon working electrode (WE) on the paper electrode (PE) was modified with gold particles (AuPs@PE) and then conjugated with anti-CD9 (Anti-CD9/AuPs@PE) for the detection of exosomes. Variables involved in the biosensor design were optimized with the univariate mode. The developed method presents the limit of detection of  8.7 × 102 exosomes mL-1, which is lower than that of many other available methods under the best conditions. The biosensor was also tested with urine samples from cancer patients with high recoveries. Due to this  a unique, low-cost, biodegradable technology is presented that can directly measure exosomes without labeling them for early cancer or metastasis detection.

Phage probe on RAFT polymer surface for rapid enumeration of E. coli K12.

This study presents a simple, fast, and sensitive label-free sensing assay for the precise enumeration of modeled pathogenic Escherichia coli K12 (E. coli K12) bacteria for the first time. The method employs the covalent binding bacteriophage technique on the surface of a reversible addition-fragmentation chain transfer (RAFT) polymer film. The Nyquist plots obtained from electrochemical impedance spectroscopy (EIS) identified the charge transfer resistance Rct was calculated from a suitable electrochemical circuit model through an evaluation of the relevant parameter after the immobilization of the bacteriophage and the binding of specific E. coli K12. The impedimetric biosensor reveals specific and reproducible detection with sensitivity in the linear working range of 104.2-107.0 CFU/mL, a limit of detection (LOD) of 101.3 CFU/mL, and a short response time of 15 min. The SERS response validates the surface roughness and interaction of the SERS-tag with E. coli K12-modified electrodes. Furthermore, the covalently immobilized active phage selectivity was proved against various non-targeting bacterial strains in the presence of targeted E.coli K12 with a result of 94 % specificity and 98 % sensitivity. Therefore, the developed phage-based electrode surface can be used as a disposable, label-free impedimetric biosensor for rapid and real-time monitoring of serum samples.

Boron-Doped Carbon Nanodots as a Theranostic Agent for Colon Cancer Stem Cells.

Carbon nanodots have drawn a great deal of attention due to their green and expedient opportunities in biological and chemical sciences. Their high fluorescence capabilities and low toxicity for living cells and tissues make them excellent imaging agents. In addition, they have a fluorimetric response against inorganic and organic species. Boron-doped carbon nanodots (B-CDs) with high fluorescence yield were produced from phenylboronic acid and glutamine as boron and carbon sources, respectively, by a hydrothermal method. First, the effects of the temperature on their fluorescence yield and the structural characteristics of B-CDs were investigated. Second, their cytotoxicity and cell death and proliferation behaviors were examined. The cytotoxicity was evaluated by the MTT assay. The cellular properties were evaluated with the distribution of caspase 3, Ki67, lamin B1, P16, and cytochrome c after the indirect immunoperoxidase technique. After the MTT assay, 1:1 dilution of all applicants for 24 h was used in the study. After immunohistochemical analyses, the application of B-CDs synthesized at 230 °C did not change control cell (Vero) proliferation, and also apoptosis was not triggered. Colo 320 CD133+ and CD133- cell-triggered apoptosis and cellular senescence were found to be synthesis temperature dependent. In addition, Colo 320 CD133- cells were affected relatively more than CD133+ cells from B-CDs. While B-CDs did not affect the control cells, the colon cancer stem cells (Colo 320 CD133+) were affected in a time-dependent manner. Therefore, the use of the synthesized B-CD product may be an alternative method for controlling or eliminating cancer stem cells in the tumor tissue.

To what extent are orally ingested nanoplastics toxic to the hippocampus in young adult rats?

As the use of plastic-containing materials in our daily lives becomes increasingly common, exposure to nanoplastics accordingly becomes inevitable. Micro and nanoplastics released from large amounts of plastic waste constitute a serious environmental problem. Therefore, this study aimed to examine the effects of polystyrene nanoplastic (PS-NP) on the hippocampus. MATERIAL AND METHOD: Thirty Wistar albino rats, 15 male and 15 female, aged 6-8 weeks, were used in the research. These were randomly divided into three groups of five males and five females each. A five-minute open field test was applied to all rats on the first and last days of the study. Three groups of rats (Control, NP1 and NP2) received the standard chow and water. Additionally, rats in the first neoplastic group (NP1) received 25 mg/kg PS-NP and rats in the second nanoplastic group (NP2) received 50 mg/kg PS-NP, at the same time each day by oral gavage. The rats were sacrificed under deep anesthesia at the end of four weeks. The hippocampi were removed and subjected to histopathological and biochemical analyses. RESULTS: Green fluorescent dots were detected in the hippocampi of both dose groups receiving nanoplastics (NPs) administered orally to female and male rats. Histopathological examination revealed neuronal degeneration in the hippocampi of male and female rats from both dose groups. However, while no significant difference was observed among the groups in terms of changes in antioxidant enzyme values and open-field test data in male rats, significant differences in peroxidase (POD) and glutathione S-transferase (GST) values and fecal boli and grooming numbers were determined in female rats exposed to NPs. In conclusion, exposure to NP substances extend as far as the hippocampus, causing neuronal damage and behavioral problems.

Fluorescent and Biocompatible Nitrogen and Sulfur Co-Doped Carbon Nanodot as an Ocular Fundus Angiography Imaging Agent.

The florescence characteristics and the toxicities of carbon nanodots (CDs) are directly related to their elemental compositions. Fluorescent and non-toxic agent for imaging of biological systems was aimed. Sulfur and nitrogen co-doped CDs (S/N-CDs) was hydrothermally produced in an average size of 8 nm. S/N-CDs showed blue fluorescence under UV-light with an excitation wavelength of 365 nm. After 24 h, S/N-CDs was non-cytotoxic in HUVEC and L929 cells. S/N-CDs have a great potential to act as an alternative material for commercial fluorescent materials with its 85.5% of quantum yield. S/N-CDs was approved in vitro as an imaging agent for an ocular fundus angiography of rats.

The change of blood Pb levels of basketball players after strenuous exercise.

This study is related to the investigation of the Pb levels in blood of the 12 healthy University male basketball players before and after a strenuous training session by the use of square wave anodic stripping voltammetry. Although the results do not show acute lead intoxication it is obvious that blood lead levels show significant increase after training sessions. The average increase in blood lead levels is 297%. This increase is largely due to increased respiration rate during the training period.

Effect of six weeks aerobic training upon blood trace metals levels.

This study was carried out to investigate the effects of 6-week aerobic exercise program upon blood Zn and Cu levels. There were 12 male university students with an average age of 21.67+/-0.89 years and no regular training habits participated in the study. The participants were subjected three days a week 1 hour a day continuous running program on treadmill with an intensity of 60-70% for a period of six weeks. They were fed with zinc and copper free diet throughout the study and it was made sure that they were not using copper or zinc containing vitamin tablets. The difference between the pre and post study period were found to be statistically significant as regards to both resting and maximal loading conditions (p<0.01). The pre and post training maxVO2 values were also found to be positively correlated with the copper and zinc levels in blood. Both the copper and zinc blood levels were found decreased after the training period p<0.05.