Changes in Botrytis cinerea Conidia Caused by Berberis vulgaris Extract

Testing plant extracts for controlling fungal diseases is a main biocontrol method. More interesting is to see what happens to the fungus treated with the plant extract. Therefore, the aim of the study was to evaluate the antifungal activity of Berberis vulgaris extract on Botrytis cinerea and to examine the ultrastructural changes in B. cinerea conidia caused by the minimum inhibitory concentration (MIC), using SEM and TEM. The antifungal activity of B. vulgaris bark extract was investigated using agar dilution method, and compared to that of berberine. Fluconazole was used as the positive antimycotic control. It was found that (1) B. vulgaris bark extract had significant antifungal activity against B. cinerea, and its effect was stronger than that of pure berberine. It was also noted that (2)B. vulgaris MIC caused severe structural changes of the conidia, comparable with berberine MIC effect; therefore (3) B. vulgaris bark extract might be recommended to be tested as a biocontrol agent against B. cinerea

Multimodal Biosensing on Paper-Based Platform Fabricated by Plasmonic Calligraphy Using Gold Nanobypiramids Ink

In this work, we design new plasmonic paper-based nanoplatforms with interesting capabilities in terms of sensitivity, efficiency, and reproducibility for promoting multimodal biodetection via Localized Surface Plasmon Resonance (LSPR), Surface Enhanced Raman Spectroscopy (SERS), and Metal Enhanced Fluorescence (MEF). To succeed, we exploit the unique optical properties of gold nanobipyramids (AuBPs) deposited onto the cellulose fibers via plasmonic calligraphy using a commercial pen. The first step of the biosensing protocol was to precisely graft the previously chemically-formed p-aminothiophenol@Biotin system, as active recognition element for target streptavidin detection, onto the plasmonic nanoplatform. The specific capture of the target protein was successfully demonstrated using three complementary sensing techniques. As a result, while the LSPR based sensing capabilities of the nanoplatform were proved by successive 13–18 nm red shifts of the longitudinal LSPR associated with the change of the surface RI after each step. By employing the ultrasensitive SERS technique, we were able to indirectly confirm the molecular identification of the biotin-streptavidin interaction due to the protein fingerprint bands assigned to amide I, amide III, and Trp vibrations. Additionally, the formed biotin-streptavidin complex acted as a spacer to ensure an optimal distance between the AuBP surface and the Alexa 680 fluorophore for achieving a 2-fold fluorescence emission enhancement of streptavidin@Alexa 680 on the biotinylated nanoplatform compared to the same complex on bare paper (near the plasmonic lines), implementing thus a novel MEF sensing nanoplatform. Finally, by integrating multiple LSPR, SERS, and MEF nanosensors with multiplex capability into a single flexible and portable plasmonic nanoplatform, we could overcome important limits in the field of portable point-of-care diagnostics

Two-photon fabrication of three-dimensional silver microstructures in microfluidic channels for volumetric surface-enhanced Raman scattering detection

International audienceWe report on the nonlinear photochemistry fabrication of three-dimensional silver (Ag) microstructures in microfluidic channels for volumetric surface-enhanced Raman scattering (3D SERS). The fabrication of high resolution 3D Ag microstructures is obtained by a two-photon induced reduction process of silver cations, which is restricted at the focal point of a Q-switched Nd:YAG microlaser (sub-nanosecond pulses at 1064 nm). Firstly, 3D Ag micro-pillars made on cover glass showed a 3D SERS detection limit of Oxazine 720 as low as 10−8 M. Secondly, we directly fabricated 3D microstructures within microfluidic channels, and demonstrated their 3D SERS capability. The micro-cube geometry gave a significantly larger 3D SERS signal than the micro-pillar geometry. This result demonstration is paving the way for further optimization routes by varying the geometry, the size, and the density of complex 3D structures which can be obtained by direct laser writing based on two-photon induced chemistry

Surface Plasmon Resonance or Biocompatibility—Key Properties for Determining the Applicability of Noble Metal Nanoparticles

Metal and in particular noble metal nanoparticles represent a very special class of materials which can be applied as prepared or as composite materials. In most of the cases, two main properties are exploited in a vast number of publications: biocompatibility and surface plasmon resonance (SPR). For instance, these two important properties are exploitable in plasmonic diagnostics, bioactive glasses/glass ceramics and catalysis. The most frequently applied noble metal nanoparticle that is universally applicable in all the previously mentioned research areas is gold, although in the case of bioactive glasses/glass ceramics, silver and copper nanoparticles are more frequently applied. The composite partners/supports/matrix/scaffolds for these nanoparticles can vary depending on the chosen application (biopolymers, semiconductor-based composites: TiO2, WO3, Bi2WO6, biomaterials: SiO2 or P2O5-based glasses and glass ceramics, polymers: polyvinyl alcohol (PVA), Gelatin, polyethylene glycol (PEG), polylactic acid (PLA), etc.). The scientific works on these materials’ applicability and the development of new approaches will be targeted in the present review, focusing in several cases on the functioning mechanism and on the role of the noble metal

Cardiac Troponin Biosensor Designs: Current Developments and Remaining Challenges

Acute myocardial infarction (AMI) is considered as one of the main causes of death, threating human lives for decades. Currently, its diagnosis relies on electrocardiography (ECG), which has been proven to be insufficient. In this context, the efficient detection of cardiac biomarkers was proposed to overcome the limitations of ECG. In particular, the measurement of troponins, specifically cardiac troponin I (cTnI) and cardiac troponin T (cTnT), has proven to be superior in terms of sensitivity and specificity in the diagnosis of myocardial damage. As one of the most life-threatening conditions, specific and sensitive investigation methods that are fast, universally available, and cost-efficient to allow for early initiation of evidence-based, living-saving treatment are desired. In this review, we aim to present and discuss the major breakthroughs made in the development of cTnI and cTnT specific biosensor designs and analytical tools, highlighting the achieved progress as well as the remaining challenges to reach the technological goal of simple, specific, cheap, and portable testing chips for the rapid and efficient on-site detection of cardiac cTnI/cTnT biomarkers in order to diagnose and treat cardiovascular diseases at an incipient stage

Designing Efficient Low-Cost Paper-Based Sensing Plasmonic Nanoplatforms

Paper-based platforms can be a promising choice as portable sensors due to their low-cost and facile fabrication, ease of use, high sensitivity, specificity and flexibility. By combining the qualities of these 3D platforms with the optical properties of gold nanoparticles, it is possible to create efficient nanodevices with desired biosensing functionalities. In this work, we propose a new plasmonic paper-based dual localized surface plasmon resonance–surface-enhanced Raman scattering (LSPR-SERS) nanoplatform with improved detection abilities in terms of high sensitivity, uniformity and reproducibility. Specifically, colloidal gold nanorods (GNRs) with a well-controlled plasmonic response were firstly synthesized and validated as efficient dual LSPR-SERS nanosensors in solution using the p-aminothiophenol (p-ATP) analyte. GNRs were then efficiently immobilized onto the paper via the immersion approach, thus obtaining plasmonic nanoplatforms with a modulated LSPR response. The successful deposition of the nanoparticles onto the cellulose fibers was confirmed by LSPR measurements, which demonstrate the preserved plasmonic response after immobilization, as well as by dark-field microscopy and scanning electron microscopy investigations, which confirm their uniform distribution. Finally, a limit of detection for p-ATP as low as 10−12 M has been achieved by our developed SERS-based paper nanoplatform, proving that our optimized plasmonic paper-based biosensing design could be further considered as an excellent candidate for miniaturized biomedical applications

Airborne pollutants collection and analysis based on their fluorescence spectral measurements: a case study on diesel exhaust combustion particles

Abstract Collection of the airborne pollutants by using our prototyped device was followed by their analyses based on the performed fluorescence spectral measurements for three samples collected on the quartz substrates and on the surface of a silicon monocrystalline (opaque) wafer. Results for combustion particulate matter from diesel exhaust, including a comparison with air pollutants analysis for microparticles collected on a street in Chisinau city during rush hour, are presented. The strength of the proposed method represents the possibility to study directly the airborne solid microparticles collected on different substrates, and it is suitable for studying air pollution on large areas and at different altitudes by using unmanned aerial vehicles (UAVs). Microparticles fluorescence spectroscopy results indicate that the individual particles exhibit composite fluorescence spectra

Microfluidic platform for integrated plasmonic detection in laminal flow

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Gold NanoBipyramids Performing as Highly Sensitive Dual-Modal Optical Immunosensors

International audienceIn this work, we demonstrate the feasibility of gold bipyramidal-shaped nanoparticles (AuBPs) to be used as active plasmonic nanoplatforms for the detection of the biotin–streptavidin interaction in aqueous solution via both Localized Surface Plasmon Resonance and Surface Enhanced Raman Scattering (LSPR/SERS). Our proof of concept exploits the precise attachment of the recognition element at the tips of AuBPs, where the electromagnetic field is stronger, which is beneficial to the surface sensitivity of longitudinal LSPR on the local refractive index and to the electromagnetic enhancement of SERS activity, too. Indeed, successive red shifts of the longitudinal LSPR associated with increased local refractive index reveal the attachment of para-aminothiophenol (p-ATP) chemically labeled Biotin to the Au surface and the specific capture of the target protein by biotin-functionalized AuBPs. Finite-Difference Time-Domain simulations based on the reconstructed index of refraction confirm LSPR measurements. However, the molecular identification of the biotin–streptavidin interaction remains elusive by LSPR investigation alone. Remarkably, we succeeded to complement the LSPR detection with reliable SERS measurements which permitted to (a) certify the molecular identification of biotin–streptavidin interaction and (b) extend the limit of detection of streptavidin in solution toward 10–12 M. Finally, to further probe the possibility to implement the AuBPs as dual LSPR-SERS based immunoassays in solution for real clinical diagnostics, we additionally investigated the AuBP’s performance to transduce the specific antihuman IgG- human IgG binding event, providing thus a reference design for building unique plasmonic immunoassays for dual-optical detection of target proteins in aqueous solution

New Amorphous Hydrogels with Proliferative Properties as Potential Tools in Wound Healing

The study and discovery of bioactive compounds and new formulations as potential tools for promoting the repair of dermoepidermal tissue in wound healing is of continuing interest. We have developed a new formulation of amorphous hydrogel based on sodium alginate (NaAlg); type I collagen, isolated by the authors from silver carp tails (COL); glycerol (Gli); Aloe vera gel powder (AV); and silver nanoparticles obtained by green synthesis with aqueous Cinnamomum verum extract (AgNPs@CIN) and vitamin C, respectively. The gel texture of the amorphous hydrogels was achieved by the addition of Aloe vera, demonstrated by a rheological analysis. The evaluations of the cytotoxicity and cell proliferation capacity of the experimental amorphous hydrogels were performed against human foreskin fibroblast Hs27 cells (CRL-1634-ATCC). The developed gel formulations did not show a cytotoxic effect. The hydrogel variant containing AgNPs@CIN in a concentration of 8 µg Ag/gel formulation and hydrogel variant with vitamin C had proliferative activity. In addition, the antibacterial activity of the hydrogels was evaluated against S. aureus ATCC 6538, Ps. aeruginosa ATCC 27853, and E. coli ATCC 25922. The results demonstrated that the gel variant based on AgNPs@CIN in a concentration of 95 µg Ag/gel formulation and the hydrogel based on vitamin C show antibacterial activity. Therefore, the developed hydrogels with AgNPs@CIN and vitamin C could be promising alternatives in wound healing