The construction of glucose biosensor based on platinum nanoclusters-multiwalled carbon nanotubes nanocomposites.

One-step synthesis method was proposed to obtain the nanocomposites of platinum nanoclusters and multiwalled carbon nanotubes (PtNCs-MWNTs), which were used as a novel immobilization matrix for the enzyme to fabricate glucose biosensor. The fabrication process of the biosensor was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy and scanning electron microscope. Due to the favorable characteristic of PtNCs-MWNTs nanocomposites, the biosensor exhibited good characteristics, such as wide linear range (3.0 µM-12.1 mM), low detection limit (1.0 µM), high sensitivity (12.8 µA mM⁻¹), rapid response time (within 6 s). The apparent Michaelis-Menten constant (K(app)(m)) is 2.1 mM. The performance of the resulting biosensor is more prominent than that of most of the reported glucose biosensors. Furthermore, it was demonstrated that this biosensor can be used for the assay of glucose in human serum samples.

[Changes of bone density and insulin-like growth factor-1 level in elders with type 2 diabetes mellitus].

OBJECTIVE: To investigate the changes of bone mineral density(BMD) and the relationship of BMD to serum Insulin-like growth factor-1 concentrations, body mass index (BMI), waist hip ratio (WHR), estradiol (E2), testosterone (T), biochemical markers of bone turnover as well as other factors in the elderly individuals with Type 2 diabetes mellitus (T2DM). METHODS: BMDs of spine were measured by quantitative CT for patients with T2DM (n=53) and health controls (n=40). The relationships of BMD related to serum Insulin-like growth factor-1 concentrations, BMI, WHR, E2, T, bone Gla'protein, bone alkaline phosphatase, tartrate resistant acid phosphatase 5b levels were also analyzed. RESULTS: The spine BMD values for the T2DM patients were significantly reduced when compared with controls [(74.75 +/- 22.70) mg/cc vs. (88.04 +/- 28.29) mg/cc, P < 0.05], and the concentration of serum Insulin-like growth factor-1 in T2DM group was significantly lower than that in control [(27.63 +/- 5.74) ng/mL vs. (32.51 +/- 9.68) ng/mL, P < 0.05]. The level of serum Insulin-like growth factor-1 was positive correlation to bone-specific alkaline phosphatase (B-ALP) in the T2DM patients (r = 0.46, P < 0.01). CONCLUSION: The spine BMD in elderly T2DM patients is lower than that in control group. The circulating serum Insulin-like growth factor-1 does not have a significant influence on bone mass in elderly T2DM patients.