Gustavo Bodelón

Accurate multiplexed immunophenotyping is essential for understanding cellular heterogeneity. Dual-mode detection strategies, such as surface-enhanced Raman scattering (SERS)-fluorescence, offer synergistic advantages and cross-validation to reduce false positives. We present a method for fabricating dual-mode nanoprobes using metal-phenolic networks (MPNs) as functional coatings on hollow plasmonic nanocapsules. Unlike conventional silica shells, MPNs enable the one-step conjugation of biorecognition elements via metal-phenolic coordination, integrating distinct Raman reporters and fluorescently labeled antibodies within a single probe. These plasmonic MPN nanoprobes achieved multiplex detection of the epidermal growth factor receptor and CD44 in cultured cells using SERS and flow cytometry. Application to mixed HER14 and HEK-293 cultures revealed population distributions of ∼63% HER14 and ∼37% HEK-293 as determined by SERS, corroborated by flow cytometry. This work highlights the potential of dual-mode plasmonic MPNs for accurate, scalable immunophenotyping, offering a robust platform for targeted cell imaging and diagnostics.

Lateral flow immunoassays (LFIAs) are easy‐to‐use antigen tests that provide different signal readouts, with colorimetric readouts being the most commonly used. However, these analytical devices have relatively low sensitivity and produce semiquantitative results, limiting their diagnostic applications. Herein, we address these challenges by implementing a digital surface‐enhanced Raman spectroscopy (SERS)‐based LFIA for the accurate and ultrasensitive quantitative detection of SARS‐CoV‐2 nucleocapsid (N) protein. Compared with average SERS intensity measurements, the digital approach allowed to overcome fluctuations in Raman scattering signals, thereby increasing the analytical sensitivity of the assay. Our method exhibited a quantification range of the viral protein in nasal swabs from 0.001 to 10 pg mL⁻¹, and a limit of detection down to 1.9 aM (0.9 fg mL⁻¹), improving colorimetric LFIAs and conventional‐SERS‐based LFIAs by several orders of magnitude. Importantly, this approach shows an analytical sensitivity of 0.03 TCID₅₀ mL⁻¹, which is greater than that reported by other immunoassays. In conclusion, we successfully demonstrate the robust detection and quantification of SARS‐CoV‐2N protein in nasal swabs at ultralow concentrations. The improvement in the sensitivity of LFIA by digital SERS may pave the way to translate this technology into the diagnostic arena for the ultrasensitive detection of microbes and disease biomarkers.

Protein cages are promising tools for the controlled delivery of therapeutics and imaging agents when endowed with programmable disassembly strategies. Here, we produced hybrid nanocomposites made of tobacco mosaic virus (TMV) and magnetic iron oxide nanoparticles (IONPs), designed to disrupt the viral protein cages using magnetically induced release of heat. We studied the effects of this magnetic hyperthermia on the programmable viral protein capsid disassembly using (1) elongated nanocomposites of TMV coated heterogeneously with magnetic iron oxide nanoparticles (TMV@IONPs) and (2) spherical nanocomposites of polystyrene (PS) on which we deposited presynthesized IONPs and TMV via layer-by-layer self-assembly (PS@IONPs/TMV). Notably, we found that the extent of the disassembly of the protein cages is contingent upon the specific absorption rate (SAR) of the magnetic nanoparticles, that is, the heating efficiency, and the relative position of the protein cage within the nanocomposite concerning the heating sources. This implies that the spatial arrangement of components within the hybrid nanostructure has a significant impact on the disassembly process. Understanding and optimizing this relationship will contribute to the critical spatiotemporal control for targeted drug and gene delivery using protein cages.

Lectin‐glycan interactions sustain fundamental biological processes involved in development and disease. Owing to their unique sugar‐binding properties, lectins have great potential in glycobiology and biomedicine. However, their relatively low affinities and broad specificities pose a significant challenge when used as analytical reagents. New approaches for expression and engineering of lectins are in demand to overcome current limitations. Herein, we report the application of bacterial display for the expression of human galectin‐3 and mannose‐binding lectin in Escherichia coli . The analysis of the cell surface expression and binding activity of the surface‐displayed lectins, including point and deletion mutants, in combination with molecular dynamics simulation, demonstrate the robustness and suitability of this approach. Furthermore, the display of functional mannose‐binding lectin in the bacterial surface proved the feasibility of this method for disulfide bond‐containing lectins. This work establishes for the first time bacterial display as an efficient means for the expression and engineering of human lectins, thereby increasing the available toolbox for glycobiology research.

Foodborne allergies and illnesses represent a major global health concern. In particular, fish can trigger life-threatening food allergic reactions and poisoning effects, mainly caused by the ingestion of parvalbumin toxin. Additionally, preformed histamine in less-than-fresh fish serves as a toxicological alert. Consequently, the analytical assessment of parvalbumin and histamine levels in fish becomes a critical public health safety measure. The multiplex detection of both analytes has emerged as an important issue. The analytical detection of parvalbumin and histamine requires different assays; while the determination of parvalbumin is commonly carried out by enzyme-linked immunosorbent assay, histamine is analyzed by high-performance liquid chromatography. In this study, we present an approach for multiplexing detection and quantification of trace amounts of parvalbumin and histamine in canned fish. This is achieved through a colorimetric and surface-enhanced Raman-scattering-based competitive lateral flow assay (SERS-LFIA) employing plasmonic nanoparticles. Two distinct SERS nanotags tailored for histamine or β-parvalbumin detection were synthesized. Initially, spherical 50 nm Au@Ag core-shell nanoparticles (Au@Ag NPs) were encoded with either rhodamine B isothiocyanate (RBITC) or malachite green isothiocyanate (MGITC). Subsequently, these nanoparticles were bioconjugated with anti-β-parvalbumin and antihistamine, forming the basis for our detection and quantification methodology. Additionally, our approach demonstrates the use of SERS-LFIA for the sensitive and multiplexed detection of parvalbumin and histamine on a single test line, paving the way for on-site detection employing portable Raman instruments.

This study compares two kinds of magnetic microbeads with different surface features and cell entry pathways, aiming to provide insights into how to program their cell uptake and intracellular fate. It is found that a rougher surface enhances the cell uptake of the microbeads, regardless of whether they are pulled by a magnetic field gradient or adsorbed by the cell membrane. However, the entry route affects the intracellular localization of the microbeads: The magnetically dragged microbeads reach the cytoplasm, while the adsorbed microbeads stay in the late endosomes and lysosomes. This suggests that different strategies can be used to target different cellular compartments with magnetic microbeads. Moreover, it is demonstrated that the cells containing the microbeads can be moved and regrown at specific locations by applying a magnetic field gradient, showing the potential of these magnetic microbeads for cell delivery and manipulation.

The agri-food industry has historically determined the socioeconomic characteristics of Galicia and Northern Portugal, and it was recently identified as an area for collaboration in the Euroregion. In particular, there is a need for action to help to ensure the provision of safe and healthy foods by taking advantage of key enabling technologies. The goals of the FOODSENS project are aligned with this major objective, specifically with the development of biosensors able to monitor hazards relevant to the safety of food produced in the Euroregion. The present review addresses the state of the art of analytical methodologies and techniques—whether commercially available or in various stages of development—for monitoring food hazards, such as harmful algal blooms, mycotoxins, Listeria monocytogenes, allergens, and polycyclic aromatic hydrocarbons. We discuss the pros and cons of these methodologies and techniques and address lines of research for point-of-care detection. Accordingly, the development of miniaturized automated monitoring strategies is considered a priority in terms of health and economic interest, with a significant impact in several areas, such as food safety, water quality, pollution control, and public health. Finally, we present potential market opportunities that could result from the availability of rapid and reliable commercial methodologies.

It is well known that microbial populations and their interactions are largely influenced by their secreted metabolites. Noninvasive and spatiotemporal monitoring and imaging of such extracellular metabolic byproducts can be correlated with biological phenotypes of interest and provide new insights into the structure and development of microbial communities. Herein, we report a surface-enhanced Raman scattering (SERS) hybrid substrate consisting of plasmonic [email protected]@mSiO₂ nanorattles for optophysiological monitoring of extracellular metabolism in microbial populations. A key element of the SERS substrate is the mesoporous silica shell encapsulating single plasmonic nanoparticles, which furnishes colloidal stability and molecular sieving capabilities to the engineered nanostructures, thereby realizing robust, sensitive, and reliable measurements. The reported SERS-based approach may be used as a powerful tool for deciphering the role of extracellular metabolites and physicochemical factors in microbial community dynamics and interactions.

The synergistic combination of noble metal nanoparticles and bacterial cells results in hybrid systems that offer new useful properties for the development of future applications and tools.

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.