Simple strategy for sensitive detection of dopamine using CdTe QDs modified glassy carbon electrode.

BACKGROUND: Cellular and brain metabolism of dopamine can be correlated with a number of neurodegenerative disorders, our study was to explore a simple and efficient method to detect dopamine in real samples. METHODS: A new quantum dots (CdTe QDs) could be prepared using the hydrothermal method, the electrochemical biosensor was established by dropping CdTe QDs on the surface of glassy carbon electrode (GCE). RESULTS: The CdTe QDs/GCE exhibited the excellent electrochemical catalytic activity toward dopamine (DA) with good stability and high sensitivity in presence of interfering substances. The detection limit of DA was calculated by differential pulse voltammetry (DPV) as low as 0.3 µmol L-1 with a linear dynamic range of 1 µmol L-1 to 400 µmol L-1 . CONCLUSION: In this paper, the proposed electrochemical biosensor could be effectively used for the direct and rapid detection of DA in human serum and urine samples.

A Label-Free Electrochemical Biosensor Based on a Reduced Graphene Oxide and Indole-5-Carboxylic Acid Nanocomposite for the Detection of Klebsiella pneumoniae.

A label-free DNA hybridization electrochemical sensor for the detection of Klebsiella pneumoniae was developed, which could be helpful in the diagnosis of bacterial infections. Indole-5-carboxylic acid (ICA) and graphene oxide (GO) were electrodeposited on a glassy carbon electrode, and the resulting reduced GO (rGO)-ICA hybrid film served as a platform for immobilizing oligonucleotides on a single-stranded DNA (ssDNA) sequence. The conditions were optimized, with excellent electrochemical performance. A significant change was observed after hybridization of ssDNA with the target probe under optimum conditions. Hybridization with complementary, noncomplementary, one-base mismatched, and three-base mismatched DNA targets was studied effectively by differential pulse voltammetry. The proposed strategy could detect target DNA down to 3 × 10-11 M, with a linear range from 1 × 10-6 M to 1 × 10-10 M, showing high sensitivity. This electrochemical method is simple, free from indicator, and shows good selectivity. Hence, electrochemical biosensors are successfully demonstrated for the detection of K. pneumoniae.

Preparation of quantum dots CdTe decorated graphene composite for sensitive detection of uric acid and dopamine.

The assembly of quantum dots (QDs) in a simply method opens up opportunities to obtain access to the full potential of assembled QDs by virtue of the collective properties of the ensembles. In this study, quantum dots CdTe and graphene (Gr) nanocomposite was constructed for the simultaneous determination of uric acid (UA) and dopamine (DA). The CdTe QDs-Gr nanocomposite was prepared by ultrasonication and was characterized with microscopic techniques. The nanocomposite modified electrode was characterized by cyclicvoltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Due to the synergistic effects between CdTe QDs and Gr, the fabricated electrode exhibited excellent electrochemical catalytic activities, good biological compatibility and high sensitivity toward the oxidation of UA and DA. Under optimum conditions, in the co-existence system the linear calibration plots for UA and DA were obtained over the range of 3-600 µM and 1-500 µM with detection limits of 1.0 µM and 0.33 µM. The fabricated biosensor also exhibits the excellent repeatability, reproducibility, storage stability along with acceptable selectivity.

[Effects of Ligustrazine Injection on Serum Cys C Level in Scierema Neonatorum Children Patients].

Objective To observe the effects of Ligustrazine Injection (LI) on serum cystatin C (Cys C) level in sclerema neonatorum (SN) children patients. Methods Totally 69 SN children patients were recrui- ted as the SN group, 39 with mild SN and 30 with moderate-severe SN. Another 30 neonates were recruited as a control group. Mild SN children patients and moderate-severe SN children patients were respectively assigned to the treatment group and the routine group according to random digit table. Children patients in the routine group received routine supportive treatment and symptomatic treatment, while those in the treatment group were additionally injected with LI (6 mg/kg, adding in 30 mL 5% glucose injection; once per day). All treatment lasted for 7 successive days. Serum level of Cys C, blood urea nitrogen (BUN) , and creatinine (Cr) were detected. The abnormality rate of Cys C, BUN, and Cr was respectively calculated, and their correlations analyzed. Meanwhile, scleroma subsidence time was observed in each group. Results The serum level of Cys C was obviously elevated more in the SN group than in the control group (t =10. 55, P <0. 01). There was no statistical difference in serum level of BUN or Cr between the control group and the SN group (t =1.50, 1. 73; P >0. 05). Serum Cys C level obviously increased in moderate-severe SN children patients than in mild SN children patients (t =2. 11 , P <0. 05); serum levels of BUN and Cr showed increasing tendency in moderate-severe SN children patients and mild SN children patients, but with no statistical difference (t =2. 07, 1. 92; P >0. 05). Linear correlation showed that serum Cys C level was respectively positively correlated with serum BUN level and serum Cr level in the SN group (r =0. 314,0. 287,P <0. 05). The abnormality rate of serum Cys C, BUN, and Cr was 72. 5% (50/69), 27. 5% (19/69), and 36. 2% (25/69), respectively. The abnormality rate of serum Cys C was significantly higher than that of BUN or Cr (x² =41. 04; P <0. 01). Compared with the routine group, serum Cys C level and scleroma subsidence time were obviously lowered in moderate-severe SN chil- dren patients and mild SN children patients of the treatment group (P <0. 05), but with no statistical difference in serum level of BUN or Cr (P >0. 05). Conclusions Serum Cys C level could reflect early renal injury in SN children patients. But LI could obviously reduce serum Cys C level, promote the recovery of renal injury of SN neonates, and shorten scleroma subsidence time.

Upregulation of miR-125b by estrogen protects against non-alcoholic fatty liver in female mice.

BACKGROUND & AIMS: Due to the protective effect of estrogen against hepatic fat accumulation, the prevalence of non-alcoholic fatty liver disease (NAFLD) in premenopausal women is lower than that in men at the same age and in postmenopausal women. Our study was to further elucidate an underlying mechanism by which estrogen prevents NAFLD from miRNA perspective in female mice. METHODS: miRNA expression was evaluated by TaqMan miRNA assay. Luciferase and ChIP assay were done to validate regulation of miR-125b by estrogen via estrogen receptor alpha (ERα). Nile red and Oil red O staining were used to check lipid content. Overexpressing or inhibiting the physiological role of miR-125b in the liver of mice through injecting adenovirus were used to identify the function of miR-125b in vivo. RESULTS: miR-125b expression was activated by estrogen via ERα in vitro and in vivo. miR-125b inhibited lipid accumulation both in HepG2 cells and primary mouse hepatocytes. Consistently, ovariectomized or liver-specific ERα knockdown mice treated with miR-125b overexpressing adenoviruses were resistant to hepatic steatosis induced by high-fat diet, due to decreased fatty acid uptake and synthesis and decreased triglyceride synthesis. Conversely, inhibiting the physiological role of miR-125b with a sponge decoy slightly promoted liver steatosis with a high-fat diet. Notably, we provided evidence showing that fatty acid synthase was a functional target of miR-125b. CONCLUSION: Our findings identify a novel mechanism by which estrogen protects against hepatic steatosis in female mice via upregulating miR-125b expression.