Sunlight‐sensitive plasmonic nanostructured composites as photocatalytic coating with antibacterial properties

Infections caused by microorganisms are a global public health problem that continually demands new antimicrobial strategies. The generation of reactive oxygen species (ROS) by photocatalytic materials is an attractive approach to combat microbes. Along these lines, titanium dioxide (TiO2) constitutes an outstanding light-driven ROS generator. However, the wide bandgap of this semiconductor limits its use to the ultraviolet range of the spectral region. Herein, nanostructured materials composed of TiO2 nanoparticles and plasmonic gold nanorods (AuNRs) are presented for the photoinactivation of bacteria by means of sunlight irradiation, aiming to extend the photocatalytic action of the nanocomposite to the visible and near-infrared ranges. It is shown that, upon simulated sunlight irradiation, the different composites as coating films show photodegradation of rhodamine B, ROS production, photocatalytic inactivation of protein function in bacterial biofilms, and strong antimicrobial activity. This approach involving AuNRs/TiO2 photocatalytic composites may pave the way for the fabrication of visible light-responsive surfaces with antimicrobial activity.Universidade de Vigo/CISU

Engineering Sub-Cellular Targeting Strategies to Enhance Safe Cytosolic Silica Particle Dissolution in Cells

Mesoporous silica particles (MSP) are major candidates for drug delivery systems due to their versatile, safe, and controllable nature. Understanding their intracellular route and biodegradation process is a challenge, especially when considering their use in neuronal repair. Here, we characterize the spatiotemporal intracellular destination and degradation pathways of MSP upon endocytosis by HeLa cells and NSC-34 motor neurons using confocal and electron microscopy imaging together with inductively-coupled plasma optical emission spectroscopy analysis. We demonstrate how MSP are captured by receptor-mediated endocytosis and are temporarily stored in endo-lysosomes before being finally exocytosed. We also illustrate how particles are often re-endocytosed after undergoing surface erosion extracellularly. On the other hand, silica particles engineered to target the cytosol with a carbon nanotube coating, are safely dissolved intracellularly in a time scale of hours. These studies provide fundamental clues for programming the sub-cellular fate of MSP and reveal critical aspects to improve delivery strategies and to favor MSP safe elimination. We also demonstrate how the cytosol is significantly more corrosive than lysosomes for MSP and show how their biodegradation is fully biocompatible, thus, validating their use as nanocarriers for nervous system cells, including motor neurons.This research was funded by ISCIII Projects ref. PI16/00496, PI19/00349, DTS19/00033, co-funded by ERDF/ESF, "Investing in Your Future"; and MICINN Projects ref. CTM2017-84050-R, NanoBioApp Network (MINECO-17-MAT2016-81955-REDT), COST action Nano2Clinic CA17140, Xunta de Galicia (Centro Singular de Investigación de Galicia-Accreditation 2016-2019 and EM2014/035), European Union FEDER Funds (European Regional Development Fund-ERDF) and IDIVAL for INNVAL 17/11, INNVAL18/28, INNVAL19/18 and the technical support

Nanostructured heterogeneous catalysts for bioorthogonal reactions

Bioorthogonal chemistry has inspired a new subarea of chemistry providing a powerful tool to perform novel biocompatible chemospecific reactions in living systems. Following the premise that they do not interfere with biological functions, bioorthogonal reactions are increasingly applied in biomedical research, particularly with respect to genetic encoding systems, fluorogenic reactions for bioimaging, and cancer therapy. This Minireview compiles recent advances in the use of heterogeneous catalysts for bioorthogonal reactions. The synthetic strategies of Pd-, Au-, and Cu-based materials, their applicability in the activation of caged fluorophores and prodrugs, and the possibilities of using external stimuli to release therapeutic substances at a specific location in a diseased tissue are discussed. Finally, we highlight frontiers in the field, identifying challenges, and propose directions for future development in this emerging field.Agencia Estatal de Investigación | Ref. PID2020-113704RB-I00Xunta de Galicia | Ref. ED431C 2022/24Xunta de Galicia | Ref. ED431H 2020/08Xunta de Galicia | Ref. ED431G 2019-06Xunta de Galicia | Ref. ED481B-2019-07

Macrophagic enhancement in optical coherence tomography imaging by means of superparamagnetic iron oxide nanoparticles

Background: The ability of optical coherence tomography (OCT) to visualise macrophages in vivo in coronary arteries is still controversial. We hypothesise that imaging of macrophages in OCT could be enhanced by means of superparamagnetic nanoparticles. Methods: We compared the optical backscattering and attenuation of cell pellets containing RAW 264.7 macrophages with those of macrophagic cell pellets labelled with very small superparamagnetic oxydised nanoparticles (VSOP) by means of light intensity analysis in OCT. The labelled macrophages were incubated with VSOP at a concentration of 1 mM Fe, corresponding to intracellular iron concentrations of 8.8 pg/cell. To study the effect of intracellular accumulation on the backscattering, VSOP dilutions without cells were also compared. OCT pullbacks of the PCR tubes containing the cell pellets were obtained and light intensity analysis was performed on raw OCT images in polar view, after normalisation by the backscattering of the PCR tube. The backscattering was estimated by the peak normalised intensity, whilst the attenuation was estimated by the number of pixels between the peak and the normalised intensity 1 (peak-to-one). Results: VSOP-loaded macrophages have higher backscattering than the corresponding unlabelled macrophages (peak normalised intensity 6.30 vs. 3.15) with also slightly higher attenuation (peak-toone 61 vs. 66 pixels). The backscattering of the nanoparticles in suspension was negligible in the light intensity analysis. Conclusions: VSOP increase significantly the optical backscattering of macrophages in the nearinfrared region, with minimal increase in signal attenuation. This finding enables the enhancement of macrophages in conventional OCT imaging with an easily implementable methodology

Tuning electro-magnetic interference shielding efficiency of customized polyurethane composite foams taking advantage of rGO/Fe3O4 hybrid nanocomposites

Electromagnetic interference (EMI) has been recognized as a new sort of pollution and can be considered as the direct interference of electromagnetic waves among electronic equipment that frequently affects their typical efficiency. As a result, shielding the electronics from this interfering radiation has been addressed as critical issue of great interest. In this study, different hybrid nanocomposites consisting of magnetite nanoparticles (Fe3O4) and reduced graphene oxide (rGO) as (conductive/magnetic) fillers, taking into account different rGO mass ratios, were synthesized and characterized by XRD, Raman spectroscopy, TEM and their magnetic properties were assessed via VSM. The acquired fillers were encapsulated in the polyurethane foam matrix with different loading percentages (wt%) to evaluate their role in EMI shielding. Moreover, their structure, morphology, and thermal stability were investigated by SEM, FTIR, and TGA, respectively. In addition, the impact of filler loading on their final mechanical properties was determined. The obtained results revealed that the Fe3O4@rGO composites displayed superparamagnetic behavior and acceptable electrical conductivity value. The performance assessment of the conducting Fe3O4@rGO/PU composite foams in EMI shielding efficiency (SE) was investigated at the X-band (8–12) GHz, and interestingly, an optimized value of SE −33 dBw was achieved with Fe3O4@rGO at a 80:20 wt% ratio and 35 wt% filler loading in the final effective PU matrix. Thus, this study sheds light on a novel optimization strategy for electromagnetic shielding, taking into account conducting new materials with variable filler loading, composition ratio, and mechanical properties in such a way as to open the door for achieving a remarkable SE.Ministerio de Ciencia e Innovación | Ref. PID2020-113704RB-I00Xunta de Galicia | Ref. ED431G 2019/06Xunta de Galicia | Ref. IN607A 2018/5Xunta de Galicia | Ref. ED431C 2021/45Unión Europea-FEDER (Interreg V-A—España-Portugal) | Ref. 0245_IBEROS_1_EUnión Europea-FEDER (Interreg V-A—España-Portugal) | Ref. 0712_ACUINANO_1_EUnión Europea-FEDER (Interreg V-A—España-Portugal) | Ref. 0624_2IQBIONEURO_6_

Cobertura de nanotubos de carbono para su empleo como sistema de anclaje de dispositivos nano y micrométricos con actividad terapéutica

Cobertura de nanotubos de carbono para su empleo como sistema de anclaje de dispositivos nano y micrométricos con actividad terapéutica. La presente invención se refiere a una cobertura de nanotubos de carbono para su empleo como sistema de anclaje a la membrana celular y de transporte hacia el citosol de dispositivos micro-nanométricos con actividad terapéutica. Asimismo se contempla una composición que comprende a) un dispositivo micro-nanométrico con actividad terapéutica, y b) una cobertura de nanotubos de carbono que recubre al dispositivo micro-nanométrico. Finalmente se contempla dicha composición para su empleo en terapias antineoplásicas y terapias dirigidas a alteraciones del sistema nervioso.Solicitud: 201600210 (16.03.2016)Nº Pub. de Solicitud: ES2577056A1 (12.07.2016)Nº de Patente: ES2577056B2 (17.01.2017

The magic cocktail: ampicillin and biosynthesized gold nanoparticles synergism against Staphylococcus aureus

Gold nanoparticles (AuNPs) have garnered attention as a potential alternative to conventional antibiotics due to their innovative antibacterial properties. This study demonstrates the successful production of biosynthetic gold nanoparticles (bAuNPs) using Pseudomonas aeruginosa (P. aeruginosa) as spherical nanostructures at 58 °C for 24 h, under alkaline pH (9.0). The successful synthesis of bAuNPs was confirmed through UV-Vis spectroscopy, exhibiting a characteristic peak within the 500–600 nm wavelength range, and the evaluation of the main functional groups and morphology were stressed by Fourier Transform Infrared Spectroscopy (FT-IR) and Transmission Electron Microscopy (TEM), respectively. Subsequently, the synthesized bAuNPs were combined with low concentrations of ampicillin and evaluated against Methicillin-Susceptible Staphylococcus aureus (MSSA) and Methicillin-Resistant Staphylococcus aureus (MRSA) through the classical serial dilution method. This innovative approach holds the potential to address the escalating issue of antibiotic resistance, providing a viable and sustainable solution.Fundação para a Ciência e a Tecnologia | Ref. UID/BIM/04293/201

The influence of miRNAs on radiotherapy treatment in prostate cancer - A systematic review

In the last years, extensive investigation on miRNomics have shown to have great advantages in cancer personalized medicine regarding diagnosis, treatment and even clinical outcomes. Prostate cancer (PCa) is the second most common male cancer and about 50% of all PCa patients received radiotherapy (RT), despite some of them develop radioresistance. Here, we aim to provide an overview on the mechanisms of miRNA biogenesis and to discuss the functional impact of miRNAs on PCa under radiation response. As main findings, 23 miRNAs were already identified as being involved in genetic regulation of PCa cell response to RT. The mechanisms of radioresistance are still poorly understood, despite it has been suggested that miRNAs play an important role in cell signaling pathways. Identification of miRNAs panel can be thus considered an upcoming and potentially useful strategy in PCa diagnosis, given that radioresistance biomarkers, in both prognosis and therapy still remains a challenge.Fundação para a Ciência e Tecnologia | Ref. SFRH/BD/138271/201

Synergistic interaction of clusters of iron oxide nanoparticles and reduced graphene oxide for high supercapacitor performance

Supercapacitors have been recognized as one of the more promising energy storage devices, with great potential use in portable electronics and hybrid vehicles. In this study, a composite made of clusters of iron oxide (Fe3O4-γFe2O3) nanoparticles and reduced graphene oxide (rGO) has been developed through a simple one-step solvothermal synthesis method for a high-performance supercapacitor electrode. Electrochemical assessment via cyclic voltammetry, galvanostatic charge–discharge experiments, and electrochemical impedance spectroscopy (EIS) revealed that the Fe3O4-γFe2O3/rGO nanocomposite showed much higher specific capacitance than either rGO or bare clusters of Fe3O4-γFe2O3 nanoparticles. In particular, specific capacitance values of 100 F g−1, 250 F g−1, and 528 F g−1 were obtained for the clusters of iron oxide nanoparticles, rGO, and the hybrid nanostructure, respectively. The enhancement of the electrochemical performance of the composite material may be attributed to the synergistic interaction between the layers of graphene oxide and the clusters of iron oxide nanoparticles. The intimate contact between the two phases eliminates the interface, thus enabling facile electron transport, which is key to attaining high specific capacitance and, consequently, enhanced charge–discharge time. Performance evaluation in consecutive cycles has demonstrated that the composite material retains 110% of its initial capacitance after 3000 cycles, making it a promising candidate for supercapacitors.Ministerio de Ciencia e Innovación | Ref. PID2020-119242RB-I00Xunta de Galicia | Ref. ED431B 2021/14Ministerio de Economía y Competitividad | Ref. PID2020-113704RB-I00Xunta de Galicia/FEDER | Ref. IN607A 2018/5Xunta de Galicia | Ref. ED431G 2019-06Interreg España-Portugal | Ref. 0712_ACUINANO_1_EInterreg España-Portugal | Ref. 0624_2IQBIONEURO_6_

Balancing near-field enhancement and hot carrier injection: plasmonic photocatalysis in energy-transfer cascade assemblies

Photocatalysisstands as a very promisingalternativeto photovoltaicsin exploitingsolar energyand storingit inchemicalproductsthrougha single-stepprocess.A centralobstacleto its broad implementationis its low conversionefficiency,motivatingresearchin differentfields to bring about a breakthroughin this technology.Using plasmonicmaterialsto photosensitizetraditionalsemiconductorphotocatalystsis a popularstrategywhose full potentialis yet to be fully exploited.In this work, we useCdS quantumdots as a bridge system,reapingenergyfrom Au nanostructuresand deliveringit to TiO2nanoparticlesservingascatalyticcenters.The quantumdots can do this by becomingan intermediatestep in a charge-transfercascadeinitiatedin theplasmonicsystemor by creatingan electron−holepair at an improvedrate due to their interactionwith the enhancednear-fieldcreatedby the plasmonicnanoparticles.Our results show a significantaccelerationin the reactionupon combiningthese elementsinhybrid colloidalphotocatalyststhat promotethe role of the near-fieldenhancementeffect, and we show how to engineercomplexesexploitingthis approach.In doing so, we also explorethe complexinterplaybetweenthe differentmechanismsinvolvedin thephotocatalyticprocess,highlightingthe importanceof the Au nanoparticles’morphologyin their photosensitizingcapabilitiesMinisterio de Universidades | Ref. 33.50.460A.752Ministerio de Ciencia e Innovación | Ref. PDC2021-121787-I00Ministerio de Ciencia e Innovación | Ref. PID2020-113704RB-I00Ministerio de Ciencia e Innovación | Ref. PID2020-118282RA-I00Ministerio de Ciencia e Innovación | Ref. PID2020-120306RB-I00Ministerio de Ciencia e Innovación | Ref. RYC2021-033818-IMinisterio de Ciencia e Innovación | Ref. TED2021-130038A-I00Ministerio de Ciencia e Innovación | Ref. TED2021-132101B-I00Xunta de Galicia | Ref. IN607A 2018/5Generalitat de Catalunya | Ref. 2020SGR00166Centro Singular de Investigación de Galicia | Ref. ED431G 201906National Natural Science Foundation of China | Ref. 22250610200Universitat Rovira i Virgili | Ref. 2021PFR-URV-B2-02United States-Israel Binational Science Foundation | Ref. 2018050Universidade de Vigo/CISU