Bioconjugates of mercaptocarboxylic acids functionalized AuNP and superoxide dismutase for superoxide electrochemical monitoring.

The use of gold nanoparticles/superoxide dismutase (AuNP/SOD) bioconjugates is described as building blocks in SOD biosensor development for the quantification of superoxide in cell culture media. AuNP functionalization with 11-mercaptoundecanoic acid (MUA) and 4-mercaptobenzoic acid (MBA) (AuNPMUA and AuNPMBA) was used to improve SOD immobilization through EDC/NHS coupling using their -COOH terminus, leading to the formation of more stable bioconjugates. AuNP and AuNP/SOD bioconjugates were characterized by SEM to determine their size and morphology, UV-Vis for optical properties, FT-IR, and Raman spectroscopies for chemical functional group analysis and EDX for elemental analysis. Electrochemical methods were used to characterize the Au/AuNP-modified electrodes. For the optimization of the biosensor architecture, different AuNP/enzyme bioconjugates were prepared by varying the amount of both enzyme and AuNP, as well as their incubation time. Finally, the biosensors incorporating the bioconjugates were characterized by fixed potential amperometry and voltammetric analysis in order to establish the enzymatic mechanism and to elucidate the best biosensor architecture for monitoring superoxide in cell culture media. The best sensitivity value for superoxide detection corresponded to 41.2 nA µM cm-2, achieved by a biosensor based on AuNPMBA/SOD bioconjugates monitored through fixed potential amperometry at 0.3 V vs. Ag/AgCl, with a limit of detection of 1.0 µM, and overall very good operational stability, maintaining 91% of the initial sensitivity after 30 days. Finally, the optimized biosensor was employed for the quantification of successive additions of superoxide in cell culture media, with excellent recovery values.

Immobilized Antibodies on Mercaptophenylboronic Acid Monolayers for Dual-Strategy Detection of 20S Proteasome.

A dual strategy for the electrochemical detection for 20S proteasome (20S) is proposed, based on the oriented immobilization of a capture monoclonal antibody (Abß) on a self-assembled monolayer of 4-mercaptophenylboronic acid (4-MPBA) on gold electrodes, which led to the Au/4-MPBA/Abß immunosensor. The methodology comprises the correlation of 20S concentration with (i) its proteolytic activity toward the Z-LLE-AMC substrate, using the Au/4-MPBA/Abß/20S, and (ii) the enzymatic activity of an alkaline phosphatase (AlkP) from the AlkP-labeled secondary antibody (Abcore-AlkP), which involves the conversion of aminophenylphosphate to the electroactive aminophenol using Au/4-MPBA/Abß/20S/Abcore-AlkP. The step-by-step construction of the immunosensor and the interactions at its surface were evaluated by surface plasmon resonance and gravimetric analysis with quartz crystal microbalance, showing a high affinity between both antibodies and 20S. Morphological analysis by scanning electron microscopy demonstrated a pattern of parallel lines upon immobilization of Abß on 4-MPBA and morphological changes to a well-organized granular structure upon binding of 20S. A voltametric and impedimetric characterization was performed after each step in the immunosensor construction. The two detection strategies were evaluated. It was shown that the immunosensor responds linearly with 20S concentration in the range between 5 and 100 µg mL-1, which corresponds to proteasome levels in serum in the case of diverse pathological situations, and LoD values of 1.4 and 0.2 µg mL-1 were calculated for the detection strategies. The immunosensor was applied to the detection of 20S in serum samples with recovery values ranging from 101 to 103%.

Electrochemical Protein-based Bioanalytical Devices for Drug Analysis.

Proteins are vital components of living cells and the loss of their native functions has been associated with a wide variety of medical conditions. From this point of view, investigation of the protein microenvironment is crucial to support the development of therapeutic approaches capable of ensuring cellular functions. Therefore, analytical assays for the detection, quantification, and characterization of proteins, drugs, and protein-drug complexes play an essential role in fundamental research and clinical applications. Electrochemistry arises as an alternative methodology for fast assessment of proteins and drugs and is attractive due to the adaptability to miniaturization and scalability of electroanalytical devices, which then can be further employed as strategies towards personalized medical care. Thus, this review summarizes electrochemical investigations in the past 10 years on protein-based analytical devices and biosensors. A general overview of electrochemical assays that integrate proteins with nanostructured materials and conductive polymers is presented. Applications of electrochemical assays and biosensors were divided into four categories. First, those designed for drug screening strategies that focus on targeting specific intracellular, extracellular, or membrane protein subdomains to modulate their functions, aggregation/misfolding of proteins, and protein degradation pathways. Then, drug metabolism assays that involve mimicking natural metabolic pathways to identify potential safety and efficacy issues related to a drug or its metabolites. The third was dedicated to electrochemical drug delivery systems with anchored drugs in the form of bioconjugates, while the fourth was dedicated to electroanalytical methodologies for quantitative drug assays, where the electroactivity of the target species is often used to correlate the electrochemical signal to their concentration.

Novel cells integrated biosensor based on superoxide dismutase on electrospun fiber scaffolds for the electrochemical screening of cellular stress.

A novel electrochemical biosensor was developed to monitor fibroblast cells stress levels for the first time in situ under external stimuli based on the recognition of superoxide anion released upon cell damage. The biosensor comprised metallized polycaprolactone electrospun fibers covered with zinc oxide for improved cell adhesion and signal transduction, whilst stable bioconjugates of mercaptobenzoic acid-functionalized gold nanoparticles/superoxide dismutase were employed as recognition bioelements. Biosensors were first tested and optimized for in situ generated superoxide detection by fixed potential amperometry at +0.3 V, with minimal interferences from electroactive species in cell culture media. L929 fibroblast cells were then implanted on the optimized biosensor surface and the biosensor morphologically characterized by scanning electron microscopy (SEM) and fluorescence microscopy, which illustrated the network-type pattern of fibroblasts adjacent to the fiber scaffold. Fibroblast stress was induced by zymosan and monitored at the cells integrated biosensor using fixed potential amperometry (CA) with a sensitivity of 26 nA cm-2 µg mL-1 zymosan and electrochemical impedance spectroscopy (EIS), with similar sensitivity of the biosensor considering the Rs and Z' parameters of around 0.13 Ω cm2 µg-1 mL and high correlation factors R2 of 0.9994. The obtained results underline the applicability of the here developed biosensor for the electrochemical screening of the fibroblast cells stress. The concept in using low-cost biocompatible polymeric fibers as versatile scaffolds for both enzyme immobilization and cell adhesion, opens a new path in developing biosensors for the in-situ investigation of a variety of cellular events.

PC-12 Cell Line as a Neuronal Cell Model for Biosensing Applications.

PC-12 cells have been widely used as a neuronal line study model in many biosensing devices, mainly due to the neurogenic characteristics acquired after differentiation, such as high level of secreted neurotransmitter, neuron morphology characterized by neurite outgrowth, and expression of ion and neurotransmitter receptors. For understanding the pathophysiology processes involved in brain disorders, PC-12 cell line is extensively assessed in neuroscience research, including studies on neurotoxicity, neuroprotection, or neurosecretion. Various analytical technologies have been developed to investigate physicochemical processes and the biosensors based on optical and electrochemical techniques, among others, have been at the forefront of this development. This article summarizes the application of different biosensors in PC-12 cell cultures and presents the modern approaches employed in neuronal networks biosensing.

Disposable superoxide dismutase biosensors based on gold covered polycaprolactone fibers for the detection of superoxide in cell culture media.

A novel and disposable biosensor based on superoxide dismutase (SOD) immobilized on gold metallized polycaprolactone electrospun polymeric fibers (PCl/Au) has been developed for the determination of superoxide (O2•-) in cell culture media. SOD biosensors were constructed employing three immobilization methods: cross-linking with EDC/NHS at a cysteine self-assembled monolayer (PCl/Au/SODCYS), biopolymer encapsulation with chitosan (PCl/Au/SODCHI) and cross-linking with glutaraldehyde (PCl/Au/SODGA). Scanning electron microscopy was performed at the three different biosensors to evaluate their surface morphologies. Biosensors were employed for the electrochemical detection of superoxide by fixed potential amperometry at different applied potentials, with two distinct enzymatic mechanisms being proposed: i) the reduction of the enzymatically generated peroxide, at -0.3 V, for which the PCl/Au/SODCHI biosensor presented the highest value of sensitivity of 40.1 µA mM-1 cm-2, and ii) the regeneration of the enzyme catalytic copper centre, at +0.3 V, for which the PCl/Au/SODCYS biosensor had the highest sensitivity value of 16.1 µA mM-1 cm-2. The proposed recognition mechanisms were further confirmed by cyclic voltammetric measurements, which enabled also to determine the amount of immobilized electroactive SOD, with highest value corresponding to the PCl/Au/SODCYS biosensor. The biosensors with best analytical performance, PCl/Au/SODCYS and PCl/Au/SODCHI, were further investigated for stability and selectivity, with best results for the PCl/Au/SODCYS, chosen for superoxide monitoring in cell culture media. The study is promising for future application of PCl/Au/SODCYS for the on-line superoxide monitoring of superoxide in cell cultures, grown directly on the biosensor itself.

Initiation of the Fixed Combination IDegLira in Patients with Type 2 Diabetes on Prior Injectable Therapy: Insights from the EASY French Real-World Study.

INTRODUCTION: Combining basal insulin (BI) with glucagon-like peptide-1 receptor agonist (GLP-1RA) is recognized as a relevant option to optimize glucose control in type 2 diabetes (T2D). The EASY real-world study aimed to evaluate the modalities of initiation and the effectiveness of the insulin Degludec plus Liraglutide (IDegLira) fixed-ratio combination in the French health care system. METHODS: A retrospective analysis included all patients with T2D and prior injectable therapy (GLP1-RA and/or insulin) who started treatment with IDegLira from September 2016 to December 2017 in 11 French diabetes centers. Baseline characteristics, reasons for IDegLira initiation, and modes of implementation were collected from the medical records. Changes in HbA1c and body weight were determined in patients with available follow-up data (nearest 6-month visit). RESULTS: IDegLira was initiated in 629 patients previously treated with GLP-1RA alone (11.6%), insulin alone (31.5% including 16.5% with BI and 14.9% with multiple daily injections [MDI]) or a free combination of GLP-1RA and insulin (56.9% including 44.8% with BI and 12.1% with MDI), associated or not with oral agents. IDegLira starting dose (mean of 29 ± 11 dose steps) most often exceeded the recommended dose, and was significantly correlated with prior BI but not GLP-1RA dosage. At initiation, mean age, body mass index (BMI) and HbA1c were 60.1 ± 10.2 years, 33.4 ± 6.2 kg/m2 and 8.8 ± 1.7%, respectively. In 461 patients with available follow-up (median 178 days), HbA1c decreased in all subgroups submitted to treatment intensification (- 1.7 ± 1.8% [p < 0.0001], - 1.2 ± 1.8% [p < 0.001] and - 0.8 ± 1.8% [p = 0.0026] in patients with prior GLP-1RA, BI or MDI therapy, respectively) but also in those switching from BI and GLP-1RA free combination (- 0.2 ± 0.9%, p = 0.0419). Significant body weight gain occurred in patients previously treated with GLP-1RA alone (+ 1.5 ± 5.8 kg, p = 0.0572) or combined to BI (+ 1.0 ± 3.1 kg, p < 0.0001) while those on BI (- 1.4 ± 4.6 kg, p = 0.0139) or MDI (- 1.4 ± 5.0 kg, p = 0.0484) experienced weight loss. CONCLUSIONS: While providing new information on the use of IDegLira in the French healthcare system, these data confirm the effectiveness of this fixed-ratio combination in the management of T2D.

Cost-Effectiveness Evaluation of a Remote Monitoring Programme Including Lifestyle Education Software in Type 2 Diabetes: Results of the Educ@dom Study.

INTRODUCTION: Telemedicine programs using health technological innovation to remotely monitor the lifestyles of patients with type 2 diabetes (T2D) can improve glycaemic control and thus reduce the incidence of complications as well as management costs. In this context, an assessment was made of the 1-year and 2-year cost-effectiveness of the EDUC@DOM telemonitoring and tele-education program. METHODS: The EDUC@DOM study was a multicentre randomized controlled trial conducted between 2013 and 2017 that compared a telemonitoring group (TMG) to a control group (CG) merged with health insurance databases to extract economic data on resource consumption. Economic analysis was performed from the payer perspective, and direct costs and indirect costs were considered. The clinical outcome used was the intergroup change in glycated haemoglobin (HbA1c) levels from baseline. Missing economic data were imputed using multiple imputation, and fitted values from a generalized linear mixed model were used to calculate the incremental cost-effectiveness ratio (ICER). Bootstrapped 95% confidence ellipses were drawn in the cost-effectiveness plan. RESULTS: The main analysis included data from 256 patients: 126 in the TMG and 130 in the CG. Incremental costs over 1 and 2 years were equal to €2129 and €5101, respectively, in favour of the TMG. Once imputed and adjusted for confounding factors, the TMG trends to a 21% cost decrease over 1 and 2 years of follow-up (0.79 [0.58; 1.08], p = 0.1452 and 0.79 [0.61; 1.03], p = 0.0879, respectively). The EDUC@DOM program led to a €1334 cost saving and a 0.17 decrease in HbA1c over 1 year and a €3144 cost saving and a 0.14 decrease in HbA1c over 2 years. According to the confidence ellipse, EDUC@DOM was a cost-effective strategy. CONCLUSION: This study provides additional economic information on telemonitoring and tele-education programs to enhance their acceptance and promote their use. In the light of this work, the EDUC@DOM program is a cost-saving strategy in T2D management. TRIAL REGISTRATION: This trial was registered in the Clinical Trials Database on 27 September 2013 under no. NCT01955031 and bears ID-RCB no. 2013-A00391-44.

CBCT imaging: a simple approach for optimising and evaluating concomitant imaging doses, based on patient-specific attenuation, during radiotherapy pelvis treatment.

OBJECTIVES: A simple, robust method, for optimising cone-beam CT (CBCT) dose and image quality for pelvis treatment, based on patient-specific attenuation. METHODS: Methods were investigated for grouping patients into four imaging categories (small [S], medium [M], large [L], extra large [XL]), based on planning-CT CTDIvol, and phantoms constructed to represent each group. CBCTs with varying kV, mA and ms honed in on the best settings, with a bladder noise of 25 HU. A patient pilot study clinically verified the new imaging settings. RESULTS: The planning CTDIvol is a reliable method for grouping patients. Phantom measurements from the S, M and L groups show doses significantly reduced (19-83% reduction), whilst the XL group required an increase of 39%. Phantom TLD measurements showed the number of scans needed to increase rectal organ at risk (OAR) dose by 1 Gy was 143 (S group) and 50 (M group). Images were qualitatively assessed as sufficient by clinicians. CONCLUSION: Patient-specific CBCT modes are in use clinically with dose reductions across all modes except Pelvis XL, keeping doses ALARP and images optimal. Consideration of OAR doses controls the number of CBCTs allowed to ensure adherence to OAR tolerance. Reporting CBCT doses in "scans per Gray" allows clinicians to make informed decisions regarding the imaging schedule and concomitant doses. ADVANCES IN KNOWLEDGE: Patient grouping at planning CT, using CTDIvol, allows for CBCT imaging protocols to be selected based on patient specific attenuation. Reporting OAR doses in terms of "scans per Gray" allows translation of imaging dose risk to the Oncologist.

Impact of a Remote Monitoring Programme Including Lifestyle Education Software in Type 2 Diabetes: Results of the Educ@dom Randomised Multicentre Study.

INTRODUCTION: Telemonitoring in type 2 diabetes (T2D) is mainly based on glucose monitoring. A new type of connected device which routinely gathers data on weight, physical activity and food intake could improve patients' diabetes control. The main aim of this study was to assess the efficacy of an at-home interventional programme incorporating such devices and lifestyle education software on diabetes control, i.e., change in HbA1c, compared to standard care. METHODS: This multicentre study randomly assigned 282 people with T2D to either a telemonitoring group (TMG) or a control group (CG) for a 1-year intervention period. While routine follow-up was maintained in the CG, TMG subjects were provided with interactive lifestyle educational software (with artificial intelligence algorithms) and connected objects (blood glucose meters, scales and actimeters) for use in their own homes and were remotely monitored by their diabetologists. Changes in HbA1c were compared between groups using a mixed linear model. RESULTS: The mean HbA1c dropped from 7.8 ± 0.8% (62 mmol/mol) to 7.4 ± 1.0% (57 mmol/mol) in the TMG and from 7.8 ± 0.8% (62 mmol/mol) to 7.6 ± 1.0% (60 mmol/mol) in the CG, resulting in an intergroup difference of - 0.16 (p = 0.06) in favour of TMG, after adjustment for confounding factors. Within TMG, the decrease in HbA1c was greater in frequent users: - 0.23% (p = 0.03) in the case of connections to telemonitoring synthesis above the median and - 0.21% (p = 0.05) in the case of connections to tele-education software above the median compared to the CG. Significant weight loss was observed in the TMG but only in women (p = 0.01). FINDINGS: The EDUC@DOM telemonitoring and tele-education device did not highlight a significant decrease in HbA1c levels compared to routine management although a slight, albeit significant improvement in glycaemic control was observed in the frequent user subgroup as well as significant weight loss but only in women. A high level of satisfaction with the connected device was recorded amongst all participants. TRIAL REGISTRATION: This trial was registered in the Clinical Trials Database on September 27, 2013, under no. NCT01955031 and bears ID-RCB number 2013-A00391-44.

Relationship between markers of insulin resistance, markers of adiposity, HbA1c, and cognitive functions in a middle-aged population-based sample: the MONA LISA study.

OBJECTIVE: To determine the relationship between markers of insulin resistance (fasting insulin and homeostasis model assessment of insulin resistance), markers of adiposity (BMI, waist circumference, and body fat), HbA1c, and cognitive performances in a middle-aged population-based sample free of diabetes. RESEARCH DESIGN AND METHODS: Our study sample consisted of 1,172 people aged 35-64 years (49% women), free of diabetes, and recruited between 2005 and 2007 in the MONA LISA survey. Cognitive functions (memory, attention, and processing speed) were evaluated by neuropsychological tests: word-list learning test, digit symbol substitution test (DSST), word fluency test, and Stroop Test. Multiple logistic regressions were used to estimate the relationship between cognitive performance and metabolic markers. We serially adjusted for age, sex, education, and occupational status (model A), additionally for income, smoking, alcohol consumption, sedentarity, and psychotropic substance use (model B), and finally, included variables linked to the metabolic syndrome (hypertension, dyslipidemia, vascular disease, and C-reactive protein) and depression (model C). RESULTS: Elevated markers of adiposity were associated with poor cognitive performance in tests evaluating processing speed. The probability of being in the lowest quartile of each test was nearly doubled for participants in the upper quartile of BMI, compared with those in the lowest one [BMI, adjusted odds ratio (OR) 2.18, P = 0.003 (DSST), and OR 2.09, P = 0.005 (Stroop Test)]. High HbA1c was associated with poor cognitive performance in DSST (adjusted OR 1.75, P = 0.037). Waist circumference was linked to poor cognitive performance in men but not in women. CONCLUSIONS: Poor cognitive performance is associated with adiposity and hyperglycemia in healthy middle-aged people.

Dementia prevention: methodological explanations for inconsistent results.

The prevention of neurodegenerative dementias, such as Alzheimer disease, is a growing public health concern, because of a lack of effective curative treatment options and a rising global prevalence. Various potential risk or preventive factors have been suggested by epidemiologic research, including modifiable lifestyle factors, such as social contacts, leisure activities, physical exercise, and diet, as well as some preventive pharmacologic strategies, such as hormone replacement therapy, nonsteroidal antiinflammatory drugs, and Ginkgo biloba. Some factors have been targeted by interventions tested in randomized controlled trials, but many of the results are in conflict with observational evidence. The aim of this paper is to review the epidemiologic data linking potential protective factors to dementia or cognitive decline and to discuss the methodological limitations that could explain conflicting results. A thorough review of the literature suggests that, even if there are consistent findings from large observational studies regarding preventive or risk factors for dementia, few randomized controlled trials have been designed specifically to prove the protective effects of interventions based on such factors on dementia incidence. Because of the multifactorial origin of dementia, it appears that multidomain interventions could be a suitable candidate for preventive interventions, but designing such trials remains very challenging for researchers.