Host-Guest Recognition-Mediated Supramolecular Aggregation-Induced Electrochemiluminescence of Iridium(III) Complexes for Nucleic Acid Bioassay.

Currently reported aggregation-induced electroluminescence (AIECL) is usually based on the electrostatic integration of luminous monomers, and its application is still limited by the low ECL efficiency and poor structural stability of electrostatic integration-based AIECL emitters. Herein, host-guest recognition-mediated supramolecular AIECL was creatively developed to overcome the defects of electrostatic-integration-based AIECL. Cucurbit[8]uril (CB[8]) as the host recognized tris (2-phenylpyridine) iridium(III) [Ir(ppy)3] as the guest to form a novel supramolecular complex Ir-CB[8]. CB[8] can not only provide a large hydrophobic cavity to efficiently load Ir(ppy)3 and enrich coreactant tripropylamine but also utilize its carbonyl-laced portals to form intramolecular hydrogen bonds to stabilize the supramolecular structure, so Ir-CB[8] revealed excellent AIECL performance. The AIECL emitter Ir-CB[8] coupled the efficient DNA walker to construct a sensing system for miRNA-16 detection. Au nanoparticles@norepinephrine (AuNPs@NE) trapped by single-strand S1 was developed to significantly quench the ECL emission of Ir-CB[8]. When the target microRNA-16 (miRNA-16) existed, H1 was opened and the sequential assembly from H2 to H7 was triggered, forming "windmill"-like DNA walker with six Pb2+-dependent leg DNA. The assembled DNA walker, which was centered on DNA structure, had high efficiency and biocompatibility and can cut S1 to keep the DNA fragment-carrying quencher AuNPs@NE away from the electrode surface, thus restoring the ECL emission of Ir-CB[8] and realizing ultrasensitive detection of miRNA-16. Supramolecular AIECL mediated by host-guest recognition provides a new way for constructing AIECL emitters with excellent structural stability and AIECL efficiency, and an Ir-CB[8] coupling "windmill"-like DNA walker builds a promising ECL-sensing system for bioassay.

Coreactant-free electrochemiluminescence of polyfluorene nanoparticle coupling double quencher for ß-amyloid1-42 detection.

ß-amyloid1-42 (Aß1-42) is a humoral biomarker for early diagnosis of Alzheimer's disease (AD), and exists at a low level in human body. Its sensitive detection is very valuable. The electrochemiluminescence (ECL) assay of Aß1-42 has attracted special attention owing to high sensitivity and simple operation. However, currently reported ECL assays for Aß1-42 usually required the introduction of exogenous coreactants to improve the detection sensitivity. Introducing exogenous coreactants will lead to non-negligible repeatability and stability problems. This work exploited poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1',3}-thiadazole)] nanoparticles (PFBT NPs) as coreactant-free ECL emitters for detecting Aß1-42. The PFBT NPs, first antibody (Ab1) and antigen Aß1-42 were successively assembled on glassy carbon electrode (GCE). Silica nanoparticles served as a carrier to grow polydopamine (PDA) in situ, and further assembled Au nanoparticles (Au NPs) and second antibody (Ab2), producing the secondary antibody complex (SiO2@PDA-Au NPs-Ab2). With its assembly on the biosensor, the ECL signal decreased since both PDA and Au NPs could quench ECL emission from PFBT NPs. The limit of detection (LOD) of 0.55 fg/mL and limit of quantification (LOQ) of 37.45 fg/mL for Aß1-42 were obtained. PFBT NPs coupling dual-quencher PDA-Au NPs created an excellent ECL system for bioassays, and constructed a sensitive analytical method for Aß1-42.

Efficacy and safety of janagliflozin as add-on therapy to metformin in Chinese patients with type 2 diabetes inadequately controlled with metformin alone: A multicentre, randomized, double-blind, placebo-controlled, phase 3 trial.

AIM: To evaluate the efficacy and safety of janagliflozin in Chinese patients with type 2 diabetes (T2D) inadequately controlled with metformin monotherapy. MATERIALS AND METHODS: This multicentre phase 3 trial included a 24-week, randomized, double-blind, placebo-controlled period, followed by a 28-week extension period. Patients (N = 421) with HbA1c of 7.0% or higher and 10.5% or less were randomized (1:1:1) to receive once-daily placebo, janagliflozin 25 or 50 mg. After the 24-week treatment period, patients on placebo were re-randomized (1:1) to janagliflozin 25 or 50 mg for the additional 28-week treatment, whereas patients on janagliflozin maintained the same therapy. The primary endpoint was the change from baseline in HbA1c to week 24. RESULTS: At week 24, the placebo-adjusted least squares mean changes of HbA1c were -0.58% and -0.58% with janagliflozin 25 and 50 mg, respectively (P < .0001 for both). The proportion of patients achieving HbA1c less than 7.0% was higher with janagliflozin 25 and 50 mg compared with placebo (41.8%, 41.7% and 28.0%, respectively). Both janagliflozin doses provided significant reductions in fasting plasma glucose, 2-hour postprandial glucose, body weight and systolic blood pressure, and improvements in high-density lipoprotein cholesterol and insulin sensitivity compared with placebo (P < .05 for all). The trends in improvement of these variables were retained during the 28-week extension period. No severe hypoglycaemia occurred throughout the whole 52-week treatment. CONCLUSIONS: Janagliflozin 25 or 50 mg once-daily added to metformin therapy significantly improved glycaemic control, reduced body weight and systolic blood pressure, improved high-density lipoprotein cholesterol and insulin sensitivity, and was generally well-tolerated by Chinese T2D patients who had poor glycaemic control with metformin monotherapy.

Assembling inner filter effect reduced SnS2 quantum dots-based hollow polymeric spherical nanoshells for ratio electrochemiluminescence bioassay.

SnS2 quantum dots (QDs) as excellent electrochemiluminescence (ECL) luminators have exhibited a good application prospect in ECL field, but the difficulty of being effectively immobilized on the electrode and inner filter effect caused by their compact packaging make the construction of SnS2 QDs-based ECL system challenging. This work developed a hollow polymeric spherical nanoshells (HPSNs) for loading SnS2 QDs. SiO2 nanoparticles (NPs) served as the carrier for the multilayer assembly of polyethyleneimine (PEI)-SnS2 QDs and polyacrylic acid (PAA). Then, SiO2 NPs were etched to produce SnS2 QDs-based HPSNs (SnS2-HPSNs), which can not only achieve the high loading of SnS2 QDs but effectively reduce their inner filter effect, revealing a significantly improved cathodic ECL performance. SnS2-HPSNs coupled with anodic luminators Ir nanorods (NRs) to construct a ratiometric ECL biosensor for detecting cardiac troponin I (cTnI) with tripropylamine (TPrA) and persulfate (S2O82-) as anodic and cathodic co-reactants, respectively. Norepinephrine (NE) and gold nanoparticles (AuNPs) were innovatively developed as dual-quencher for Ir NRs. The secondary antibody complex containing SnS2-HPSNs and NE-AuNPs was specially constructed and its assembly on the biosensor modified with Ir NRs can conveniently realize the different changes of the two signals, thus achieving the sensitive detection of cTnI with a detection limit of 0.32 pg/mL. The HPSNs provided an effective strategy for high loading of QDs while reducing their inner filter effect. The integration of two luminators (SnS2-HPSNs and Ir NRs) and dual-quencher created a promising ECL ratio platform for the accurate detection of various biomarkers.

Dual-emitting BP-CdTe QDs coupled with dual-function moderator TiO2 NSs for electrochemiluminescence ratio bioassay.

The limitation of the selection of dual-emitting luminophor and dual-function moderator makes the construction of single-luminophor-based electrochemiluminescence (ECL) ratio strategy extremely challenging. This work developed black phosphorus nanosheet loaded with CdTe quantum dots (BP-CdTe QDs) as dual-emitting luminophor, and TiO2 nanosheets (NSs) as dual-function moderator to construct single-luminophor-based ECL ratio biosensor for amyloid-ß protein (Aß) detection. The BP-CdTe QDs modified glassy carbon electrode (GCE) firstly captured the anti-Aß1, and then the target Aß. Finally, the secondary antibody composites containing N,N-diethylethylenediamine (DEDA) and TiO2 NSs were captured on the electrode surface. DEDA in the secondary antibody composites and S2O82- added in the detection solution served as the anodic and cathodic co-reactants, respectively, and TiO2 NSs as co-reaction accelerator can simultaneously enhance two emissions. The increase of target concentration made the two signals show different increasing trend, thus achieving a sensitive ratio detection of target Aß with the detection limit of 21 fg/mL. The dual-emitting BP-CdTe QDs coupled with dual-function moderator TiO2 NSs provide an attractive single-luminophor-based ECL ratio platform for bioassay, which can not only be applied to the detection of Aß, but also to the detection of other disease biomarkers.

Custom-Molded Offloading Footwear Effectively Prevents Recurrence and Amputation, and Lowers Mortality Rates in High-Risk Diabetic Foot Patients: A Multicenter, Prospective Observational Study.

BACKGROUND: Recurrence of high-risk diabetic feet, after wound, healing is a common challenge among diabetic patients. Continuous use of an offloading device significantly prevents recurrence of high-risk diabetic feet, although patient adherence is imperative to ensuring this therapy's clinical efficacy. In this study, we explored clinical outcomes of patients with a high-risk diabetic foot who had been prescribed with custom-molded offloading footwear under different adherence conditions. METHODS: A total of 48 patients (17 females and 31 males) with high-risk diabetic feet, who had been with prescribed offloading footwear in 13 medical centers across 4 cities, were enrolled in the current study. The patients were assigned into either continuous offloading therapy (COT, n = 31) or interrupted offloading therapy (IOT, n = 17) groups, according to their adherence to the therapy. All patients were followed up monthly, and differences in recurrence, amputation, and deaths between the groups were analyzed at 4 months after therapy. RESULTS: Forty-eight patients met our inclusion criteria and were therefore included in the final analysis. Among them, 31 were stratified into the COT group and adhered to offloading therapy throughout the study period, whereas 17 were grouped as IOT and exhibited interrupted adherence to offloading therapy. We found statistically significant differences in recurrence rates (0 vs 38.46%, p < 0.01), amputation (0 vs 11.76%, p < 0.01), and deaths (0% vs 5.88%, p < 0.01) between the groups during follow-up. CONCLUSION: Patients' adherence is imperative to efficacy of custom-molded offloading footwear during treatment of high-risk diabetic foot. Further studies are needed to elucidate the role of improved design of the offloading device and the need for enhanced patient education for improved adherence.

Association of metabolic syndrome components with circulating levels of cytokine clusters in young women.

BACKGROUND: The purpose of this study was to investigate the relationship between circulating zinc α 2-glycoprotein (ZAG), irisin, betatrophin and adiponectin concentrations and metabolic syndrome (MetS) components and to analyze the effects of blood glucose and insulin on these cytokine concentrations in vivo. METHODS: A total of 196 young women, including 78 healthy women and 118 women with MetS components, were recruited for this cross-sectional study. An oral glucose tolerance test and euglycemic-hyperinsulinemic clamp (EHC) were performed in healthy subjects and women with MetS components. An ELISA kit was used to measure serum ZAG, irisin, betatrophin, and adiponectin levels, and their relationship with the MetS components was analyzed. RESULTS: In women with MetS components, circulating irisin and betatrophin levels were significantly higher than those in the healthy women ((207 (150-248) vs 178 (147-228); P < 0.05) for irisin; (0.51 (0.38-0.63) vs 0.38 (0.23-0.52); P < 0.001) for betatrophin), but circulating ZAG and adiponectin levels were significantly lower (39.8 (26.4-50.4) vs (46.7 (40.6-63.0); P < 0.001) for ZAG; (36.5 (22.0-47.6) vs 41.2 (35.7-54.7); P < 0.01) for adiponectin). FBG, WC, and triglyceride were significantly correlated with the circulating levels of these four cytokines (P < 0.001 or <0.05). All four cytokines were associated with MetS and its components. In response to increasing insulin levels, circulating ZAG concentrations were markedly increased in both healthy subjects and women with MetS components during the EHC. However, serum irisin, betatrophin, and adiponectin levels in both healthy subjects and women with MetS components were significantly reduced compared with baseline. CONCLUSION: Serum ZAG, irisin, betatrophin and adiponectin were associated with MetS and might be biomarkers for screening MetS components.

Association between circulating zinc-α2-glycoprotein levels and the different phenotypes of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) diagnosis combines various clinical phenotypes. The definition of PCOS is still controversial because insulin resistance (IR) and dysmetabolism do not constitute PCOS diagnostic criteria. We analyzed whether a circulating biomarker zinc-α2-glycoprotein (ZAG) related to IR and metabolic dysfunction can predict PCOS phenotypes. We then recruited 100 PCOS patients and 99 healthy women as the control group to assess the relationship between ZAG and metabolic characteristics. The euglycemic-hyperinsulinemic clamp helped assess insulin sensitivity, and the enzyme immunometric assay was deployed for ZAG levels. Our PCOS cohort presented sixty-nine patients with hyperandrogenism, eighty-six patients with chronic oligoanovulation, and eighty-one patients with polycystic ovaries by ultrasonographic evaluation. Additionally, the circulating ZAG levels were considerably reduced in all PCOS patients compared with healthy women (p < 0.05 or p < 0.01). Additionally, sixty-nine PCOS patients had IR, and circulating ZAG levels were also different among the phenotypes. Furthermore, the normoandrogenic type specifically exhibited the highest circulating ZAG levels among all PCOS phenotypes (p < 0.05 or p < 0.01). Additionally, normoandrogenic phenotype patients had reduced HOMA-IR scores and greater M-values than those in the classic phenotypes (p < 0.05). The circulating ZAG levels, however, were not associated with oligoanovulation but were correlated with hyperandrogenism and PCO morphology. In summary, circulating ZAG levels serve as suitable PCOS phenotype biomarkers, aiding physicians to identify women who merit screening.

A ratiometric electrochemiluminescent immunoassay for calcitonin by using N-(aminobutyl)-N-(ethylisoluminol) and graphite-like carbon nitride.

A ratiometric electrochemiluminescent (ECL) assay is described for the determination of the calcium(II) regulator calcitonin (CT). The method is making use of (a) graphite-like carbon nitride (g-C3N4) as the cathodic luminophore, (b) N-(aminobutyl)-N-(ethylisoluminol) (ABEI) as the anodic luminophore, and (c) peroxodisulfate and dissolved oxygen as coreactants. The luminous potential of g-C3N4 and ABEI can be well distinguished because of their different luminescent properties. Energy transfer between g-C3N4 and ABEI is not observed, and the coreactants peroxodisulate and oxygen do not interfere with each other. Au nanoparticles were functionalized with g-C3N4 and placed on the electrode to serve as a matrix for immobilization of primary antibody (Ab1). In the presence of CT, it will bind to the electrode. Then secondary antibody (Ab2) modified with polyaniline (PANI) and ABEI is incubated onto the electrode. With the increase in the concentration of CT, the blue ECL of g-C3N4 is quenched by PANI, while the blue luminescence of ABEI is enhanced. This enables ratiometric detection of calcitonin by ratioing the internsities at 460 and 475 nm. Response is linear in the 0.1~40 pg·mL-1 CT concentration range, and the limit of detection is 23 fg·mL-1. The method breaks the limitation of common ECL ratiometric strategy, namely, two luminophores often share the common coreactant. Graphical abstractSchematic representation of an immunoassay where polyaniline (PANI) in a BSA-Ab2-ABEI-Au@PANI composite quenches the cathodic signal of a graphitic carbon nitride (Au-g-C3N4) modified with gold nanoparticles (Au), while N-(aminobutyl)-N-(ethylisolumino) (ABEI) in the BSA-Ab2-ABEI-Au@PANI composit produces an anodic signal that enables quantitation of calcitonin.

A novel electrochemiluminescent biosensor based on resonance energy transfer between poly(9,9-di-n-octylfluorenyl-2,7-diyl) and 3,4,9,10-perylenetetracar-boxylic acid for insulin detection.

An electrochemiluminescencent (ECL) biosensor was designed for the determination of insulin using a novel ECL resonance energy transfer (ECL-RET) strategy. In this strategy, carboxyl poly(9,9-dioctyfluorenyl-2,7-diyl) dots (PFO dots) were worked as ECL donor and 3,4,9,10-perylenetetracar-boxylic acid (PTCA) exploited as ECL acceptor, and hydrogen peroxide (H2O2) employed as the coreactant. The ECL donor and ECL acceptor were separately labeled with primary antibody (Ab1) and secondary antibody (Ab2), forming a sensing interface to the analyte target, insulin. In this expected sandwich-type ECL biosensor, PFO dots acted as sensing platform and PTCA employed as labels to quench the ECL emission of PFO dots. During the determination process, ECL signal of PFO dots was decreased in a gradual way by the increase of insulin concentration, and the quenching mechanism was also investigated. Under the optimal experimental conditions, the constructed biosensor exhibited an excellent performance, including a wide linear range from 1.0 × 10-5ng/mL to 1.0 × 102ng/mL, low detection limit of 3.0 × 10-6ng/mL, good stability and selectivity for the detection of insulin. This pair of PFO-PTCA, as a new donor-acceptor pair in ECL-RET system, would provide a promising platform for bioanalysis in ECL field.

A dual-potential electrochemiluminescence ratiometric sensor for sensitive detection of dopamine based on graphene-CdTe quantum dots and self-enhanced Ru(II) complex.

A novel dual-potential ratiometric electrochemiluminescence (ECL) sensor was designed for detecting dopamine (DA) based on graphene-CdTe quantum dots (G-CdTe QDs) as the cathodic emitter and self-enhanced Ru(II) composite (TAEA-Ru) as the anodic emitter. TAEA-Ru was prepared by linking ruthenium(II) tris(2,2'-bipyridyl-4,4'-dicarboxylato) with tris(2-aminoethyl)amine. Firstly, 3-aminopropyltriethoxysilane founctionalized G-CdTe QDs was used as the substrate for capturing target DA via the specific recognition of the diol of DA to the oxyethyl group of APTES. Then, Cu2O nanocrystals supported TAEA-Ru was further bound by the strong interaction between amino groups of DA and carboxyl groups of the Cu2O-TAEA-Ru. With the increase in DA concentration, the loading of Cu2O-TAEA-Ru at the electrode increased. As a result, the anodic ECL signal from TAEA-Ru increased, and the cathodic ECL signal from G-CdTe QDs/O2 system decreased correspondingly. Such a decrease was resulted from the ECL resonance energy transfer (RET) from G-CdTe QDs to TAEA-Ru as well as the dual quenching effects of Cu2O to G-CdTe QDs, namely the ECL-RET from G-CdTe QDs to Cu2O and the consumption of coreactant O2 by Cu2O. Based on the ratio of two ECL signals, the determination of DA was achieved with a linear range from 10.0 fM to 1.0nM and a detection limit low to 2.9 fM (S/N=3). The combination of G-CdTe QDs/O2 and TAEA-Ru would break the limitation of the same coreatant shared in previous ECL ratiometric systems and provide a potential application of ECL ratiometric sensor in the detection of biological small molecules with the assistance of the dual molecular recognition strategy.

An ultrasensitive electrochemiluminescence biosensor for the detection of concanavalin A based on Au nanoparticles-thiosemicarbazide functionalized PtNi nanocubes as signal enhancer.

A sandwich-configuration electrochemiluminescence (ECL) biosensor was constructed for detecting concanavalin A (ConA) based on peroxydisulfate/oxygen (S2O82-/O2) system. In this work, the gold nanoflower modified Zn-doped SnO2 was used as a substrate to adsorb recognition element horseradish peroxidase (HRP) for binding ConA. Then, Au nanoparticles-thiosemicarbazide functionalized PtNi nanocubes (AuNPs-TSC-PtNi NCs), as a novel ECL signal tracer, were incubated onto the electrode through a specific carbohydrate-ConA interaction, thus achieving a sandwiched structure. The integration of amplifying effect of both TSC and PtNi NCs on the ECL of S2O82-/O2 system endowed the biosensor a high sensitivity. The linear range for ConA detection was from 0.0010ng/mL to 10ng/mL with a detection limit of 0.0002ng/mL (S/N=3).

Effect of metformin treatment during pregnancy on women with PCOS: a systematic review and meta-analysis.

PURPOSE: Some previous studies have found that continued metformin use is beneficial in the management of polycystic ovary syndrome (PCOS) in pregnant women. A systemic review and meta-analysis were needed to more fully assess the effects of metformin on pregnant PCOS patients. METHODS: The literature was fully searched using MEDLINE, EMBASE, SCOPUS, and COCHRANE for continued metformin use during pregnancy in women with PCOS. A systematic review and meta-analysis were performed to evaluate the comprehensive effects of continued metformin treatment on pregnancy-related outcomes in these women. RESULTS: Eleven eligible studies out of 127 relevant publications were included in meta-analysis. The rates of early pregnancy loss and preterm delivery were found to be significantly decreased in metformin-treated PCOS women. A non-significant difference was found in fetal abnormality and fetal birth weight between the metformin-treated and the non-treated groups. The incidence of gestational diabetes mellitus (GDM) and hypertension/preeclampsia were not significantly different in the two groups, probably because of inconsistent results in the subgroup analysis. CONCLUSIONS: Our results showed that continued use during of metformin, during pregnancy in women with PCOS, had no effect on incidence of fetal abnormalities or fetal birth weight. The effects of metformin on GDM and hypertension/preeclampsia should be determined through high-quality randomized controlled trials.

Efficacy and safety of saxagliptin monotherapy or added to metformin in Chinese patients with type 2 diabetes mellitus: results from the 24-week, post-marketing SUNSHINE study.

BACKGROUND: The aim of the present study was to explore the efficacy and safety of saxagliptin in a large Chinese population with type 2 diabetes mellitus (T2DM). METHODS: In all, 1423 T2DM patients from 92 research centers, either drug naïve or uncontrolled by metformin, were enrolled in this single-arm cohort study; patients were treated with saxagliptin 5 mg once daily for 24 weeks. The primary efficacy endpoint was the change from baseline in HbA1c at 24 weeks in the per-protocol analysis set. Secondary endpoints included the proportion of patients achieving HbA1c <7% and changes from baseline in fasting plasma glucose (FPG) and 2-h postprandial plasma glucose (PPG) concentrations at 24 weeks. Safety endpoints included adverse events (AEs) and the incidence of hypoglycemia. RESULTS: Among 1210 patients in the per-protocol analysis set, mean HbA1c, FPG and 2-h PPG decreased by 1.61 ± 0.04%, 0.55 ± 0.07 mmol/L, and 2.83 ± 0.27 mmol/L, respectively, at week 24. The proportion of patients achieving HbA1c <7% was 44.1%. No new (previously unreported) AEs occurred. The incidence of serious AEs and hypoglycemia was low (1.8% and 1.2%, respectively). There were no significant differences in efficacy endpoints in subgroup analyses by age, creatinine clearance, body mass index, or treatment background. In elderly patients (≥65 years) and those with mild renal impairment (50 < CCr ≤ 80 mL/min), the incidence of AEs was similar to that of the entire study population. CONCLUSIONS: Saxagliptin significantly improved glycemic control and was well tolerated in Chinese T2DM patients, including the elderly and patients with mild renal impairment.

A signal-on electrochemiluminescence biosensor for detecting Con A using phenoxy dextran-graphite-like carbon nitride as signal probe.

A novel signal-on electrochemiluminescence (ECL) biosensor for detecting concanavalin A (Con A) was fabricated with phenoxy dextran-graphite-like carbon nitride (DexP-g-C3N4) as signal probe. In this construction strategy, the nanocomposites of three-dimensional graphene and gold nanoparticles (3D-GR-AuNPs) were used as matrix for high loading of glucose oxidase (GOx), which served as recognition element for bounding Con A. Con A further interacted with DexP-g-C3N4 through a specific carbohydrate-Con A interaction to achieve a sandwiched scheme. With the increase of Con A incubated onto the electrode, the ECL signal resulted from DexP-g-C3N4 would enhance, thus achieving a signal-on ECL biosensor for Con A detection. Due to the integration of the virtues of 3D-GR-AuNPs and the excellent ECL performance of DexP-g-C3N4, the prepared biosensor exhibits a wide linear response range from 0.05 ng/mL to 100 ng/mL and a low detection limit of 17 pg/mL (S/N=3).

Highly sensitive electrochemiluminescence biosensors for cholesterol detection based on mesoporous magnetic core-shell microspheres.

A sensitive electrochemiluminescence (ECL) biosensor for cholesterol detection based on multifunctional core-shell structured microspheres (Fe3O4@SiO2-Au@mpSiO2) is reported. This microsphere consisted of a core of silica-coated magnetite nanoparticle, an active transition layer of gold nanoparticles and a mesoporous silica shell. Scanning electron microscopy was employed to observe the morphology of the nanomaterials and transmission electron microscopy was used to further confirm the subtle structure of Fe3O4@SiO2-Au@mpSiO2. The microspheres possessed a large surface area that increased enzyme loading, and an active transition layer gold nanoparticles enhanced the ECL signal. They were used to immobilize cholesterol oxidase for cholesterol detection with a high sensitivity, low detection limit and wide linear range. The linear range was from 0.83 to 2.62 mM with a detection limit of 0.28 µM (S/N = 3). Moreover, the reproducibility, stability and selectivity of the biosensor were established.

Highly-sensitive cholesterol biosensor based on platinum-gold hybrid functionalized ZnO nanorods.

A novel scheme for the fabrication of gold/platinum hybrid functionalized ZnO nanorods (Pt-Au@ZnONRs) and multiwalled carbon nanotubes (MWCNTs) modified electrode is presented and its application for cholesterol biosensor is investigated. Firstly, Pt-Au@ZnONRs was prepared by the method of chemical synthesis. Then, the Pt-Au@ZnONRs suspension was dropped on the MWCNTs modified glass carbon electrode, and followed with cholesterol oxidase (ChOx) immobilization by the adsorbing interaction between the nano-material and ChOx as well as the electrostatic interaction between ZnONRs and ChOx molecules. The combination of MWCNTs and Pt-Au@ZnONRs provided a favorable environment for ChOx and resulted in the enhanced analytical response of the biosensor. The resulted biosensor exhibited a linear response to cholesterol in the wide range of 0.1-759.3 µM with a low detection limit of 0.03 µM and a high sensitivity of 26.8 µA mM(-1). The calculated apparent Michaelis constant K(M)(app) was 1.84 mM, indicating a high affinity between ChOx and cholesterol.

[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.