Achieving high hybridization density at DNA biosensor surfaces using branched spacer and click chemistry.

The COVID-19 pandemic has highlighted the necessity to develop fast, highly sensitive and selective virus detection methods. Surface-based DNA-biosensors are interesting candidates for this purpose. Functionalization of solid substrates with DNA must be precisely controlled to achieve the required accuracy and sensitivity. In particular, achieving high hybridization density at the sensing surface is a prerequisite to reach a low limit of detection. We herein describe a strategy based on peptides as anchoring units to immobilize DNA probes at the surface of borosilicate slides. While the coating pathway involves copper-catalyzed click chemistry, a copper-free variation is also reported. The resulting biochips display a high hybridization density (2.9 pmol per cm2) with their targeted gene sequences.

A DNA biosensors-based microfluidic platform for attomolar real-time detection of unamplified SARS-CoV-2 virus.

The emergence of the coronavirus 2019 (COVID-19) arose the need for rapid, accurate and massive virus detection methods to control the spread of infectious diseases. In this work, a device, deployable in non-medical environments, has been developed for the detection of non-amplified SARS-CoV-2 RNA. A SARS-CoV-2 specific probe was designed and covalently immobilized at the surface of glass slides to fabricate a DNA biosensor. The resulting system was integrated in a microfluidic platform, in which viral RNA was extracted from non-treated human saliva, before hybridizing at the surface of the sensor. The formed DNA/RNA duplex was detected in presence of SYBR Green I using an opto-electronic system, based on a high-power LED and a photo multiplier tube, which convert the emitted fluorescence into an electrical signal that can be processed in less than 10 min. The limit of detection of the resulting microfluidic platform reached six copies of viral RNA per microliter of sample (equal to 10 aM) and satisfied the safety margin. The absence of non-specific adsorption and the selectivity for SARS-CoV-2 RNA were established. In addition, the designed device could be applicable for the detection of a variety of viruses by simple modification of the immobilized probe.

[Red yeast-rice-induced muscular injuries: Analysis of French pharmacovigilance database and literature review]. / Atteintes musculaires et levure de riz rouge : analyse des données de la base nationale de pharmacovigilance et revue de la littérature.

Red yeast rice (RYR) is a dietary supplement containing monacolins obtained by fermentation of Monascus purpureus strains. Because of its structural homology with lovastatin, monacolin K inhibits HMG-CoA reductase and shows hypocholesterolemic properties comparable to synthetic statins. We studied all cases of myopathy involving RYR reported in the French national pharmacovigilance database (6 cases) and in scientific literature (9 cases). Among these cases, 9 showed elevated creatine kinase, 3 rhabdomyolysis and 2 myalgia. Recent studies seem to show good efficacy of the RYR, however, our work reports the existence of related muscular disorders. In addition, dietary supplements currently available on the market may show considerable variability of formulation and/or the presence of contaminants. When clinicobiological disorders occur, physicians should consider the eventual use of an herbal treatment.

Core-Shell Structured Chitosan-Polyethylenimine Nanoparticles for Gene Delivery: Improved Stability, Cellular Uptake, and Transfection Efficiency.

The delivery of nucleic acids relies on vectors that condense and encapsulate their cargo. Especially nonviral gene delivery systems are of increasing interest. However, low transgene expression levels and limited tolerability of these systems remain a challenge. The improvement of nucleic acid delivery using depolymerized chitosan-polyethylenimine DNA complexes (dCS-PEI/DNA) is investigated. The secore complexes are further combined with chitosan-based shells and functionalized with polyethylene glycol (PEG) and cell penetrating peptides. This modular approach allows to evaluate the effect of functional shell components on physicochemical particle characteristics and biological effects. The optimized ternary complex combines a core-dCS-linear PEI/DNA complex with a shell consisting of dCS-PEG-COOH, which results in improved nucleic acid encapsulation, cellular uptake and transfection potency in human hepatoma HuH-7cells and murine primary hepatocytes. Effects on transgene expression are confirmed in wild-type mice following retrograde intrabiliary infusion. After administration of only 100 ng complexed DNA, ternary complexes induced a high reporter gene signal for three days. It is concluded that ternary coreshell structured nanoparticles comprising functionalized chitosan can be used for in vitro andin vivo gene delivery.

Specific and sensitive detection of Influenza A virus using a biotin-coated nanoparticle enhanced immunomagnetic assay.

This study reports the development of a sensitive magnetic bead-based enzyme-linked immunoassay (MELISA) for the pan-reactive detection of the Influenza A virus. The assay combines immunomagnetic beads and biotin-nanoparticle-based detection to quantify a highly conserved viral nucleoprotein in virus lysates. At the capture step, monoclonal antibody-coated magnetic microbeads were used to bind and concentrate the nucleoprotein in samples. The colorimetric detection signal was amplified using biotinylated silica nanoparticles (NP). These nanoparticles were functionalized on the surface with short DNA spacers bearing biotin groups by an automated supported synthesis method performed on nano-on-micro assemblies with a DNA/RNA synthesizer. A biotin-nanoparticle and immunomagnetic bead-based assay was developed. We succeeded in detecting Influenza A viruses directly in the lysis buffer supplemented with 10% saliva to simulate the clinical context. The biotin-nanoparticle amplification step enabled detection limits as low as 3 × 103 PFU mL-1 and 4 × 104 PFU mL-1 to be achieved for the H1N1 and H3N2 strains respectively. In contrast, a classical ELISA test based on the same antibody sandwich showed detection limit of 1.2 × 107 PFU mL-1 for H1N1. The new enhanced MELISA proved to be specific, as no cross-reactivity was found with a porcine respiratory virus (PRRSV). Graphical abstract.

Design and Preparation of Sensing Surfaces for Capacitive Biodetection.

Despite their high sensitivity and their suitability for miniaturization, biosensors are still limited for clinical applications due to the lack of reproducibility and specificity of their detection performance. The design and preparation of sensing surfaces are suspected to be a cause of these limitations. Here, we first present an updated overview of the current state of use of capacitive biosensors in a medical context. Then, we summarize the encountered strategies for the fabrication of capacitive biosensing surfaces. Finally, we describe the characteristics which govern the performance of the sensing surfaces, along with recent developments that were suggested to overcome their main current limitations.

Incretin-based drugs and intestinal obstruction: A pharmacovigilance study.

AIMS: To investigate the risk of intestinal obstruction associated with incretin-based drugs by performing a disproportionality analysis of adverse reaction reports in a global pharmacovigilance database. METHODS: We conducted a case/non-case analysis using VigiBase, the World Health Organization's adverse drug reactions (ADR) database, to assess intestinal obstruction reporting associated with incretin-based drugs (glucagon-like peptide 1 analogues [GLP-1a] and dipeptidyl peptidase 4 inhibitors [DPP-4i]. Cases were defined as reports of gastrointestinal stenosis and obstruction (MedDRA High Level Group Term) and non-cases were all other reactions recorded. Disproportionality analysis were performed by computing reporting odds ratios (ROR) with their 95% confidence interval (95%CI) within all ADR reports concerning diabetes drugs from January 2007 to January 2018 and in a restricted sample including only serious reports. RESULTS: A total of 501,244 ADR with diabetes drugs were reported in VigiBase during the study period. We identified 452 intestinal obstructions involving an incretin-based drug. In disproportionality analyses, intestinal obstructions were more than 4.5 times more frequently reported with incretin-based drugs than with other diabetes drugs (ROR 4.52, 95% CI: 3.87-5.28) with a higher signal for serious cases and for DPP-4i (ROR 8.66, 95% CI: 7.27-10.32) compared to GLP-1a (ROR 3.05, 95% CI: 2.54-3.66). CONCLUSIONS: We identified a pharmacovigilance signal that suggests a risk of potentially serious intestinal obstruction associated with incretin-based drugs, as a class and with a greater signal for DPP4-i. Other studies are needed to confirm and better understand the potential risk of intestinal obstruction associated with incretin-based drugs.

Gallium(iii)-polypyridyl complexes as anti-osteosarcoma stem cell agents.

Gallium(iii) complexes with polypridyl ligands are shown to kill bulk osteosarcoma cells and osteosarcoma stem cells (OSCs) with up to nanomolar potency. The most effective complex induces apoptosis in osteosarcoma cells by damaging genomic DNA. To the best of our knowledge this is the first investigation into metal-based anti-OSC agents.

SGLT-2 inhibitors and ketoacidosis: a disproportionality analysis in the World Health Organization's adverse drug reactions database.

SGLT-2 inhibitors, also called gliflozins, are a new class of drugs used in type 2 diabetes. Since their marketing, several cases of ketoacidosis, including life-threatening conditions, were reported with their use. The objective of this study was to investigate the disproportionality of pharmacovigilance reports of ketoacidosis between gliflozins and other drugs used for type 2 diabetes. We performed a case-noncase study within the World Health Organization's pharmacovigilance database, VigiBase. We selected all reports of serious adverse drug reaction associated with a glucose-lowering drug in patients aged 40 years and older, from January 2013 to March 2016. Cases were the reports of ketoacidosis and noncases were all other serious adverse drug reactions reported. We studied the disproportionality of reports of ketoacidosis for gliflozins by calculating reporting odds ratios (ROR) with their 95% confidence interval (95% CI). We also measured the disproportionality before the warnings issued by the US and European medicines agencies. A total of 68 555 notifications were selected. We identified 487 cases of ketoacidosis exposed to gliflozins. Ketoacidosis was significantly more frequently reported with gliflozins than with other glucose-lowering drugs (adjusted ROR 15.5; 95% CI: 12.8-18.7). The disproportionality of gliflozin reports was also found before the alerts of the medicines agencies. Our study shows a significant and early pharmacovigilance signal which suggests an increased risk of ketoacidosis associated with the use of gliflozins in patients with diabetes. Further studies are needed to confirm this potential risk.