Sustainable energy technologies necessitate efficient and reliable energy-storage systems complementing renewable energy generation. Supercapacitors offer superior power density and cycling stability, making them indispensable for high-power applications. Silicon, the cornerstone of microelectronics, is an earth-abundant material whose nanostructured forms, particularly silicon nanowires (SiNWs), exhibit promising electrochemical and optoelectronic properties. Here we report the fabrication and characterization of fractal and quantum confined SiNW-based supercapacitors exhibiting a fourfold enhancement in specific capacitance under simulated solar illumination. Electrochemical measurements reveal typical non-faradic behavior, with specific capacitance increasing from approximate to 300 mu F/cm2 in the dark to approximate to 1.2 mF/cm2 under illumination. The results highlight the potential of SiNWs as photocapacitors for next-generation electrochemical energy-storage devices.

Electrochemical surface-enhanced Raman spectroscopy (EC-SERS) is an advanced analytical technique that integrates the molecular specificity and high sensitivity of surface-enhanced Raman scattering with the dynamic control of electrochemistry. This hybrid approach enables real-time investigation of interfacial processes, including adsorption phenomena, charge-transfer interactions, and redox reactions at electrified surfaces. In recent years, significant progress has been achieved through the development of engineered plasmonic substrates, hybrid nanomaterials, and improved spectroelectrochemical configurations, greatly enhancing sensitivity, stability, and analytical performance.This review provides a critical overview of EC-SERS advancements over the last few years, focusing on substrate design strategies, methodological developments, and applications in energy systems, catalysis, and sensing with particular attention to analytical figures of merit, including sensitivity, selectivity, reproducibility, and quantitative reliability. Despite notable progress, several challenges remain, including signal variability, substrate heterogeneity, and limited standardization across studies. Finally, emerging approaches aimed at overcoming these limitations are discussed, highlighting the potential of EC-SERS as a robust and versatile platform for next-generation analytical sensing and in situ characterization of complex electrochemical interfaces.

Silicon plays a crucial role in modern microelectronics and telecommunications. Recent advancements in nanotechnology have expanded its applications, particularly in photonics. Quantum confinement effects in silicon nanostructures, such as nanocrystals and nanowires (Si NWs), enable light emission in the visible-to-near-infrared (IR) spectrum at room temperature. Among these, Si NWs are particularly promising as they are compatible with existing microelectronic fabrication processes. Given the importance of near-IR light sources for telecommunications, research has focused on enhancing the silicon-based emission in this spectral range. This study presents the development of a hybrid light-harvesting antenna composed of quantum-confined Si NWs and Ru-(II)/Os-(II)-based dendrons. By leveraging energy transfer processes, these hybrid systems achieve near-IR emission at ∼920 nm with a remarkable 99.5% efficiency, as confirmed by lifetime measurements. The dye was anchored to the Si NWs via a carboxyl-functionalized bipyridine ligand, enhancing the stability of these hybrid systems. The demonstrated Si NWs/RuOs2 hybrid antenna offers significant advantages, including high energy transfer efficiency, stability, and compatibility with cost-effective silicon technology making these structures promising candidate for photonic applications.

Accurate identification and characterization of allergenic proteins at the molecular level are essential for pinpointing the specific protein structures responsible for allergic reactions, thus advancing the development of precise diagnostic tests. Significant efforts have been focused on novel experimental techniques aimed at deepening the understanding of the underlying molecular mechanisms of these reactions. In this work, we show, for the first time to our knowledge, the unique Raman fingerprint of three Parietaria judaica (Par j) allergenic proteins. These proteins are typically present in pollen and are known to trigger severe respiratory diseases. In our research, we further exploited the surface-enhanced Raman scattering (SERS) effect from an Ag dendrite substrate. This approach provided better discrimination and a comprehensive analysis of the proteins Par j 1, 2, and 4 in hydration conditions, enabling rapid differentiation between them through a spectroscopic study.

The exponential increase in environmental pollutants due to industrialization, urbanization, and agricultural intensification has underscored the urgent need for sensitive, selective, and real-time monitoring technologies. Among emerging analytical tools, organic fluorescent sensors have demonstrated exceptional potential for detecting a wide range of pollutants in water, air, and soil, with a limit of detection (LOD) in the pM–µM range. This review critically examines recent advances in organic fluorescent sensors, focusing on their photophysical properties, molecular structures, sensing mechanisms, and environmental applications. Key categories of organic sensors, including small molecules, polymeric materials, and nanoparticle-based systems, are discussed, highlighting their advantages, such as biocompatibility, tunability, and cost-effectiveness. Comparative insights into inorganic fluorescent sensors, including quantum dots, are also provided, emphasizing their superior photostability and wide operating range (in some cases from pg/mL up to mg/mL) but limited biodegradability and higher toxicity. The integration of nanomaterials and microfluidic systems is presented as a promising route for developing portable, on-site sensing platforms. Finally, the review outlines current challenges and future perspectives, suggesting that fluorescent sensors, particularly organic ones, represent a crucial strategy toward sustainable environmental monitoring and pollutant management.

In this work, we present a highly sensitive method for the detection of biomolecules by Surface-Enhanced Raman Spectroscopy (SERS), exploiting the unique plasmonic properties of a silver (Ag) dendritic layer. This three-dimensional (3D) material is produced as a waste by-product during the metal-assisted chemical etching (MACE) process used to synthesize silicon nanowires. The fractal structure of the dendritic Ag layer is able to efficiently trap the light inside the micro- and nanocavities, forming numerous and very intense hot-spot regions that amplify Raman signals over a wide range of excitation wavelengths (from UV to IR spectral region). Furthermore, the sponge-like behavior of the Ag platform allows for the encapsulation and confinement of extremely small liquid volumes of the sample. This allows proteins to maintain their natural hydration shell, enabling the analysis of biomolecules in an environment that mimics the physiological conditions. This represents a significant advantage both in basic research and for biomedical and biochemical studies.

Silicon is the most diffused material in the industry; thus, considering its high capacity for energy storage, silicon‐based materials are well studied as battery anodes and supercapacitors. Si nanowires (NWs) emerge due to the high surface to volume ratio, its compatibility with a wafer processing typical of microelectronics, and are studied as anodes for lithium batteries as well as coupled with other materials for supercapacitor application. In this article, the synthesis and application are reported as a lithium anode of 2D fractal arrays of ultrathin Si NWs obtained by a thin‐film metal‐assisted chemical etching (MACE). These Si NWs exhibit a density of about 1012 NWs cm−2, maximizing the surface to volume ratio compared to silver‐salts MACE and other NW fabrication approaches. By using 2.7 μm long NWs, a pseudo‐capacitor behavior with a specific capacitance of about 274.2 μF cm−2at a scan rate of 50 mV s−1is obtained. This specific capacitance is two orders of magnitude higher than the one obtained in the same condition by using NWs synthesized by silver‐salt MACE. In this result, the route is opened toward the application of these fractal arrays of ultrathin Si NWs as substrate for supercapacitors with improved efficiency.

Silicon nanowires (Si NWs) are considered an outstanding material for several applications. We have realized quantum-confined and room-temperature luminescent Si NWs. These Si NWs exhibit a high-aspect ratio, and high sensitive and selective label-free detection has been demonstrated for proteins, small extracellular vesicles, and DNAs. The realization of a SARS-CoV-2 Si NW sensor able to detect a few virus copies and remain unaffected by the variant (such as Omicron) is reported, paving the way for new, cheap, optical label-free devices for the primary health care diagnosis with an industrially compatible approach.

An innovative biosensing strategy for the diagnosis of Alzheimer’s disease (AD) in human sera has been developed. The technology relied on a silicon flat substrate that was functionalized to perform a phage display detection of anti-amyloid beta (Aβ) antibodies, as AD markers, among the pool of IgGs of human sera. The substrate was derivatized with an interface able to bind and orient the IgGs for the detection operated by an engineered selective probe phage. The interface chemistry and its discrimination activity of healthy and AD sera have been fully characterized.

This study presents a breakthrough in the detection of polycyclic aromatic hydrocarbons (PAHs), particularly pyrene, recognized as persistent organic pollutants (POPs) with significant bioaccumulation and cancer risks. An optical sensor based on silicon nanowires (Si NWs) is presented, leveraging an approach that combines silane treatment and functionalization with 6-monodeoxy-6-monoamino-beta-cyclodextrin. This method innovatively utilizes the quantum-confinement properties of Si NWs and noncovalent interactions for molecular recognition, enabling highly sensitive pyrene detection in water without prior treatment. The anchoring of beta-CD quenches the optical emission of quantum-confined carriers in Si NWs, whereas the inclusion of pyrene in the receptor cavity restores the luminescence of the system, producing a disruption of luminescence quenching induced by the analyte. The sensor achieves a limit of detection (LoD) of 2 x 10(-4) ppb and a limit of quantification (LoQ) of 0.01 ppb, covering a dynamic range over 6 orders of magnitude. This advancement integrates nanophotonics and supramolecular chemistry, marking a significant leap in environmental monitoring methodologies.

Microbial colonization on plastic polymers has been extensively explored, however the temporal dynamics of biofilm community in Antarctic environments are almost unknown. As a contribute to fill this knowledge gap, the structural characteristics and microbial diversity of the biofilm associated with polyvinyl chloride (PVC) and polyethylene (PE) panels submerged at 5 m of depth and collected after 3, 9 and 12 months were investigated in four coastal sites of the Ross Sea. Additional panels placed at 5 and 20 m were retrieved after 12 months. Chemical characterization was performed by FTIR-ATR and Raman (through Surface-Enhanced Raman Scattering, SERS) spectroscopy. Bacterial community composition was quantified at a single cell level by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) and Confocal Laser Scanning Microscopy (CLSM); microbial diversity was assessed by 16S rRNA gene sequencing. This multidisciplinary approach has provided new insights into microbial community dynamics during biofouling process, shedding light on the biofilm diversity and temporal succession on plastic substrates in the Ross Sea. Significant differences between free-living and microbial biofilm communities were found, with a more consolidated and structured community composition on PVC compared to PE. Spectral features ascribable to tyrosine, polysaccharides, nucleic acids and lipids characterized the PVC-associated biofilms. Pseudomonadota (among Gammaproteobacteria) and Alpha-proteobacteria dominated the microbial biofilm community. Interestingly, in Road Bay, close to the Italian "Mario Zucchelli" research station, the biofilm growth - already observed during summer season, after 3 months of submersion - continued afterwards leading to a massive microbial abundance at the end of winter (after 12 months). After 3 months, higher percentages of Gamma-proteobacteria in Road Bay than in the not-impacted site were found. These observations lead us to hypothesize that in this site microbial fouling developed during the first 3 months could serve as a starter pioneering community stimulating the successive growth during winter.

Prosthetic joint replacement is the most widely used surgical approach to repair large bone defects, although it is often associated with prosthetic joint infection (PJI), caused by biofilm formation. To solve the PJI problem, various approaches have been proposed, including the coating of implantable devices with nanomaterials that exhibit antibacterial activity. Among these, silver nanoparticles (AgNPs) are the most used for biomedical applications, even though their use has been limited by their cytotoxicity. Therefore, several studies have been performed to evaluate the most appropriate AgNPs concentration, size, and shape to avoid cytotoxic effects. Great attention has been focused on Ag nanodendrites, due to their interesting chemical, optical, and biological properties. In this study, we evaluated the biological response of human fetal osteoblastic cells (hFOB) and P. aeruginosa and S. aureus bacteria on fractal silver dendrite substrates produced by silicon-based technology (Si_Ag). In vitro results indicated that hFOB cells cultured for 72 h on the Si_Ag surface display a good cytocompatibility. Investigations using both Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacterial strains incubated on Si_Ag for 24 h show a significant decrease in pathogen viability, more evident for P. aeruginosa than for S. aureus. These findings taken together suggest that fractal silver dendrite could represent an eligible nanomaterial for the coating of implantable medical devices.

The pandemic outbreak caused by SARS-CoV-2 coronavirus brought a crucial issue in public health causing up to now more than 600 million infected people and 6.5 million deaths. Conventional diagnostic methods are based on quantitative reverse transcription polymerase chain reaction (RT-qPCR assay) and immuno-detection (ELISA assay). However, despite these techniques have the advantages of being standardized and consolidated, they keep some main limitations in terms of accuracy (immunoassays), time/cost consumption of analysis, the need for qualified personnel, and lab constrain (molecular assays). There is crucial the need to develop new diagnostic approaches for accurate, fast and portable viral detection and quantification. Among these, PCR-free biosensors represent the most appealing solution since they can allow molecular detection without the complexity of the PCR. This will enable the possibility to be integrated in portable and low-cost systems for massive and decentralized screening of SARS-CoV-2 in a point-of-care (PoC) format, pointing to achieve a performant identification and control of infection. In this review, the most recent approaches for the SARS-CoV-2 PCR-free detection are reported, describing both the instrumental and methodological features, and highlighting their suitability for a PoC application.

The search for improved transducers to fabricate better-performing (bio)sensors is a challenging but rewarding endeavor aiming to better diagnose and treat diseases. In this paper, we report on the decoration of a dense vertical array of ultrathin silicon nanowires (Si NWs), produced by metal-assisted chemical etching, with 20 nm gold nanoparticles (Au NPs) for surface-enhanced Raman scattering (SERS) applications. To optimize the production of a uniform 3D SERS active platform, we tested different Si NW surface functionalizations with various alkoxysilanes before Au decoration. Scanning electron microscopy investigations confirm that Au NPs decorate both bare and (3-glycidiloxypropyl)trimethoxysilane (GPTMS)-modified Si NWs with a high surface coverage uniformity. The SERS response of the decorated NWs was probed using a model dye system (methylene blue; MB) at 633 and 785 nm excitation wavelengths. The GPTMS-modified NWs present the highest enhancements of 2.9 and 2.6 for the 450 cm−1 and 1625 cm−1 peaks under 785 nm excitation and of 10.8 and 5.3 for the 450 cm−1 and 1625 cm−1 peaks under 633 nm excitation. These results demonstrate the perspective role of Si NWs decorated with Au NPs as a low-cost 3D SERS platform.

Abstract The recent SARS‐CoV‐2 pandemic has highlighted the urgent need for novel point‐of‐care devices to be promptly used for a rapid and reliable large screening analysis of several biomarkers like genetic sequences and antibodies. Currently, one of the main limitations of rapid tests is the high percentage of false negatives in the presence of variants and, in particular for the Omicron one. We demonstrate in this work the detection of SARS‐CoV‐2 and the Omicron variant with a cost‐effective silicon nanosensor enabling high sensitivity, selectivity, and fast response. We have shown that a silicon (Si) nanowires (NW) platform detects both Sars‐CoV‐2 and its Omicron variant with a limit of detection (LoD) of four effective copies (cps), without any amplification of the genome, and with high selectivity. This ultrasensitive detection of 4 cps allows to obtain an extremely early diagnosis paving the way for efficient and widespread tracking. The sensor is made with industrially compatible techniques, which in perspective may allow easy and cost‐effective industrialization.

Silicon nanowires (Si NWs) represent one of the most promising platforms to be integrated into modern nanodevices. The fabrication of a dense array of vertically aligned ultrathin Si NWs using a low-cost, maskless approach and compatible with Si technology will be here demonstrated. Si NWs with efficient light emission at room temperature (RT) represent a great advance industry, paving the way for a wide range of unexpected photonic applications. In this work I will show the realization of a new hybrid material based on the luminescence of Si NWs and two different dyes for light-harvesting antennas applications, without any surface functionalization and with energy transfer efficiencies higher than 90%. The luminescence of Si NWs has also been used for sensing applications by the realization of highly sensitive sensors for the detecting of low concentrations of toxic gases. These sensors allow the detection of toxic gases below the threshold limits for human health, through both optical and electrical transduction. The achievement of light emission from silicon-based materials represents a revolution in the industrial field, as it paves the way for new Si applications.

The arising of new physical phenomena at the nanoscale promoted for the scientific community the emerging of silicon nanostructures for future challenging technologies involving innovative applications in light management and photonics. Silicon nanowires (Si NWs) are already considered strategic systems for very different applications such as microelectronics, energy, and sensors. Nonetheless, the use of Si NWs for photonic applications is very limited. The reason for these poor results in the photonic field is related to the fabrication methods that generally are used to obtain silicon nanowires. One of the most promising approaches to realize Si NWs with a low-cost and Si technology compatibility is metal-assisted chemical etching. In this paper, we report a review of silicon nanowires realized by metal chemical etching for photonic applications focusing our attention on the realization of light-emitting Si NWs.