Wirelessly powered drug-free and anti-infective smart bandage for chronic wound care

We present a wirelessly powered ultraviolet-C (UVC) radiation-based disinfecting bandage for sterilization and treatment in chronic wound care and management. The bandage contains embedded low-power UV light-emitting diodes (LEDs) in the 265 to 285 nm range with the light emission controlled via a microcontroller. An inductive coil is seamlessly concealed in the fabric bandage and coupled with a rectifier circuit to enable 6.78 MHz wireless power transfer (WPT). The maximum WPT efficiency of the coils is 83% in free space and 75% on the body at a coupling distance of 4.5 cm. Measurements show that the UVC LEDs are emitting radiant power of about 0.6 mW and 6.8 mW with and without fabric bandage, respectively, when wirelessly powered. The ability of the bandage to inactivate microorganisms was examined in a laboratory which shows that the system can effectively eradicate Gram-negative bacteria, Pseudoalteromonas sp. D41 strain, on surfaces in six hours. The proposed smart bandage system is low-cost, battery-free, flexible and can be easily mounted on the human body and, therefore, shows great promise for the treatment of persistent infections in chronic wound care

DNA detection by surface enhanced Raman spectroscopy coupled with microfluidic

Ce travail présente une méthode originale de détection et de quantification, sans étape de marquage, de la proportion de bases libres contenues dans des acides nucléiques. La spectrométrie de diffusion Raman exaltée de surface (DRES ou SERS en anglais) nous a permis d’obtenir la signature spectrale spécifique des nucléotides caractéristiques des ARN (adénosine, cytosine, guanosine et uridine), en utilisant des colloïdes d’argent comme substrat-DRES et des ajouts de MgCl2 comme agent d’agrégation. Les conditions de détection ont été optimisées pour établir un protocole de quantification de la proportion des nucléobases non-appariées par spectrométrie DRES. Les limites de détection obtenues sont de l’ordre de quelques dizaines de picomoles. L’amélioration de la reproductibilité des mesures par spectrométrie DRES passe par le contrôle précis des temps de réaction (adsorption et agrégation), qui peut être contrôlé grâce à l’utilisation de plateformes microfluidiques adaptées. Nous avons mis en œuvre deux types de plateformes microfluidiques, l’une basée sur des écoulements monophasiques et l’autre sur la génération de gouttes. Les espèces à analyser sont contenus dans les gouttes, permettant la détection in situ par spectrométrie DRES des divers nucléotides.This work deals with the development of an original label-free method for free bases proportions detection and quantification of nucleic acids. The surface enhanced Raman spectroscopy (SERS) allowed obtaining the specific spectral signature of characteristic nucleotides of RNA (adenosine, cytosine, guanosine and uridine), using silver colloids as SERS substrate and MgCl2 addition as aggregating agent. Then, the condition detection have optimizing to establish a label-free quantification protocol of free nucleobases proportion by SERS spectroscopy. The detection limits obtained are order of few picomoles. The reproducibility improvement of SERS detection requires the precise control of time reaction (adsorption and aggregation), which could be control thanks to microfluidic chips use. We have implemented two different microfluidic chips, one based on single-phase flows and one other based on droplets generation. The analyzed species are containing in droplets, allowing in situ detection by spectroscopy SERS of various nucleotides

DNA detection by surface enhanced Raman spectroscopy coupled with microfluidic

Ce travail présente une méthode originale de détection et de quantification, sans étape de marquage, de la proportion de bases libres contenues dans des acides nucléiques. La spectrométrie de diffusion Raman exaltée de surface (DRES ou SERS en anglais) nous a permis d’obtenir la signature spectrale spécifique des nucléotides caractéristiques des ARN (adénosine, cytosine, guanosine et uridine), en utilisant des colloïdes d’argent comme substrat-DRES et des ajouts de MgCl2 comme agent d’agrégation. Les conditions de détection ont été optimisées pour établir un protocole de quantification de la proportion des nucléobases non-appariées par spectrométrie DRES. Les limites de détection obtenues sont de l’ordre de quelques dizaines de picomoles. L’amélioration de la reproductibilité des mesures par spectrométrie DRES passe par le contrôle précis des temps de réaction (adsorption et agrégation), qui peut être contrôlé grâce à l’utilisation de plateformes microfluidiques adaptées. Nous avons mis en œuvre deux types de plateformes microfluidiques, l’une basée sur des écoulements monophasiques et l’autre sur la génération de gouttes. Les espèces à analyser sont contenus dans les gouttes, permettant la détection in situ par spectrométrie DRES des divers nucléotides.This work deals with the development of an original label-free method for free bases proportions detection and quantification of nucleic acids. The surface enhanced Raman spectroscopy (SERS) allowed obtaining the specific spectral signature of characteristic nucleotides of RNA (adenosine, cytosine, guanosine and uridine), using silver colloids as SERS substrate and MgCl2 addition as aggregating agent. Then, the condition detection have optimizing to establish a label-free quantification protocol of free nucleobases proportion by SERS spectroscopy. The detection limits obtained are order of few picomoles. The reproducibility improvement of SERS detection requires the precise control of time reaction (adsorption and aggregation), which could be control thanks to microfluidic chips use. We have implemented two different microfluidic chips, one based on single-phase flows and one other based on droplets generation. The analyzed species are containing in droplets, allowing in situ detection by spectroscopy SERS of various nucleotides

Effect of the Interaction of the Amyloid β (1–42) Peptide with Short Single-Stranded Synthetic Nucleotide Sequences: Morphological Characterization of the Inhibition of Fibrils Formation and Fibrils Disassembly

The formation of extracellular neuritic plaques in the brain of individuals who suffered from Alzheimer's disease (AD) is a major pathological hallmark. These plaques consist of filamentous aggregates of the amyloid beta (1–42) (Aβ42) proteins. Prevention or reduction of the formation of these fibrils is foreseen as a potential therapeutic approach. In this context, we investigated the interactions between the Aβ42 protein and polyions, in particular short single stranded synthetic nucleotide sequences. The experimental outcomes reported herein provide evidence of the inhibition of amyloid fibril genesis as well as disassembly of existing fibers through electrostatic interaction between the Aβ42 protein and the polyions. Since the polyions and the Aβ42 protein are oppositely charged, the formation of (micellar) inter polyelectrolyte complexes (IPECs) is likely to occur. Since the abnormal deposition of amyloid fibers is an archetype of AD, the outcomes of these investigations, supported by atomic force microscopy imaging in the dry and liquid states, as well as circular dichroism and Fourier transform infrared spectroscopy, are of high interest for the development of future strategies to cure a disease that concerns an ever aging population

Fast compressive Raman micro-spectroscopy to image and classify microplastics from natural marine environment

The fast and reliable detection of micron-sized plastic particles from the natural marine environment is an important topic that is mostly addressed using spontaneous Raman spectroscopy. Due to the long (>tens of ms) integration time required to record a viable Raman signal, measurements are limited to a single point per microplastic particle or require very long acquisition times (up to tens of hours). In this work, we develop, validate, and demonstrate a compressive Raman technology using binary spectral filters and single-pixel detection that can image and classify six types of marine microplastic particles over an area of 1mm2 with a pixel dwell time down to 1.75 ms/pixel and a spatial resolution of 1 µm. This is x10-100 faster than reported in previous studies

SERS Spectra of Oligonucleotides as Fingerprints to Detect Label-Free RNA in Microfluidic Devices

Probing specific RNA sequences is an issue of major significance for which fluorescence dominates most of the investigation strategies and relies heavily on the use of specific labels. In this paper, we report the detection by SERS (surface-enhanced Raman scattering) of unlabeled model purified oligonucleotides RNA polyadenosine (5′-AAA­AAA­AAA­A-3′) and polycytosine (5′-CCC­CCC­CCC­C-3′) combining silver nanoparticles as enhancing surfaces with microfluidic platforms to control species movement and the aggregation state of the nanoparticles, which is critical for the sensitivity. Two types of microfluidic platforms have been evaluated and compared: one based on laminar streams and the other involving flowing droplets acting as chemical reactors. Both platforms provide homogeneous and controlled mixing conditions of nanoparticles with oligonucleotides: laminar streams induce mixing driven by diffusion, whereas droplets permit fast and efficient mixing through internal fluid recirculation and prevent channel clogging by nanoparticles. We demonstrate that in both cases, the bases can be detected selectively. In the droplet microfluidic system, the Raman maximum enhancement is localized in the center of the droplet and observed after a certain period of mixing time that appears specific for each base, after droplet formation. It appears to be a highly promising approach for probing unlabeled nucleotides using SERS

On the horns of a dilemma: Evaluation of synthetic and natural textile microfibre effects on the physiology of the pacific oyster Crassostrea gigas

Fast fashion and our daily use of fibrous materials cause a massive release of microfibres (MF) into the oceans. Although MF pollution is commonly linked to plastics, the vast majority of collected MF are made from natural materials (e.g. cellulose). We investigated the effects of 96-h exposure to natural (wool, cotton, organic cotton) and synthetic (acrylic, nylon, polyester) textile MF and their associated chemical additives on the capacity of Pacific oysters Crassostrea gigas to ingest MF and the effects of MF and their leachates on key molecular and cellular endpoints. Digestive and glycolytic enzyme activities and immune and detoxification responses were determined at cellular (haemocyte viability, ROS production, ABC pump activity) and molecular (Ikb1, Ikb2, caspase 1 and EcSOD expression) levels, considering environmentally relevant (10 MF L−1) and worst-case scenarios (10 000 MF L−1). Ingestion of natural MF perturbed oyster digestive and immune functions, but synthetic MF had few effects, supposedly related with fibers weaving rather than the material itself. No concentration effects were found, suggesting that an environmental dose of MF is sufficient to trigger these responses. Leachate exposure had minimal effects on oyster physiology. These results suggest that the manufacture of the fibres and their characteristics could be the major factors of MF toxicity and stress the need to consider both natural and synthetic particles and their leachates to thoroughly evaluate the impact of anthropogenic debris. Environmental Implication. Microfibres (MF) are omnipresent in the world oceans with around 2 million tons released every year, resulting in their ingestion by a wide array of marine organisms. In the ocean, a domination of natural MF- representing more than 80% of collected fibres-over synthetic ones was observed. Despite MF pervasiveness, research on their impact on marine organisms, is still in its infancy. The current study aims to investigate the effects of environmental concentrations of both synthetic and natural textile MF and their associated leachates on a model filter feeder

On the horns of a dilemma: Evaluation of synthetic and natural textile microfibre effects on the physiology of the pacific oyster Crassostrea gigas

International audienc

Effect of the Interaction of the Amyloid β (1–42) Peptide with Short Single-Stranded Synthetic Nucleotide Sequences: Morphological Characterization of the Inhibition of Fibrils Formation and Fibrils Disassembly

The formation of extracellular neuritic plaques in the brain of individuals who suffered from Alzheimer’s disease (AD) is a major pathological hallmark. These plaques consist of filamentous aggregates of the amyloid beta (1–42) (Aβ₄₂) proteins. Prevention or reduction of the formation of these fibrils is foreseen as a potential therapeutic approach. In this context, we investigated the interactions between the Aβ₄₂ protein and polyions, in particular short single stranded synthetic nucleotide sequences. The experimental outcomes reported herein provide evidence of the inhibition of amyloid fibril genesis as well as disassembly of existing fibers through electrostatic interaction between the Aβ₄₂ protein and the polyions. Since the polyions and the Aβ₄₂ protein are oppositely charged, the formation of (micellar) inter polyelectrolyte complexes (IPECs) is likely to occur. Since the abnormal deposition of amyloid fibers is an archetype of AD, the outcomes of these investigations, supported by atomic force microscopy imaging in the dry and liquid states, as well as circular dichroism and Fourier transform infrared spectroscopy, are of high interest for the development of future strategies to cure a disease that concerns an ever aging population

Synthetic toxic Aβ1–42 oligomers can assemble in different morphologies

International audienceBackground Alzheimer's disease is the most common neurodegenerative disease associated with aggregation of Aβ peptides. Aβ toxicity is mostly related to the capacity of intermediate oligomers to disrupt membrane integrity. We previously expressed Aβ1–42 in a eukaryotic cellular system and selected synthetic variants on their sole toxicity. The most toxic mutant G37C forms stable oligomers. Methods Different biophysical methods (Fluorescence spectroscopy, cross-linking, mass spectrometry (MS), Small Angle X-ray Scattering (SAXS), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), calcein leakage) were used. Results The oligomers are mostly populated by a 14 mers resulting from the packing of homodimers. These homodimers come from the formation of a disulfide bridge between two monomers. This link stabilizes the multimers and prevents the assembly into amyloid fibrils. These oligomers affect the membrane integrity. The reduction of disulfide bonds leads to a rearrangement and redirects assembly of Aβ amyloid fibrils. Conclusion The toxic synthetic AβG37C mutant can assemble into an amyloid of unusual morphology through the formation of anti-parallel β-sheets. This pathway involves the formation of oligomers resulting from the arrangement of Aβ dimers linked by covalent di-sulfide link, being these oligomers harmful for the membranes. General significance The capacity to produce large amount of stable oligomers without additional detergents or extrinsic cross-linkers allow further structural and biophysical studies to understand their capacity to assemble and disrupt the membranes, a key event in Alzheimer's disease