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Nature provides various organisms with ordered or quasi-ordered dielectric nanostructures that enable several animals, plants, and protists to manipulate light, optimizing inter- and intra-species communication, camouflage, or solar light harvesting. In particular, diatom microalgae possess nanostructured silica cell walls, known as frustules, which efficiently interact with optical radiation through multiple diffractive, refractive, scattering, waveguiding, and frequency down-conversion mechanisms. These properties contribute to diatoms' efficiency in photosynthesis, UV tolerance, and possibly influence the phototaxis mechanisms of motile species. In our study, we utilized several imaging, spectroscopic, and numerical techniques to explore the optical functionalities of individual frustule components in the pennate, motile diatom Pleurosigma strigosum. We discuss the implications of frustule photonic properties on the living cell, and envision the exploitation of these properties in multifunctional, bio-derived photonic devices. [ABSTRACT FROM AUTHOR]

Nucleic acids are essential biomolecules for the functioning of cells. In past years, nucleic acids have been assessing their role in prognostics and diagnostics. The progress of nanotechnology has allowed the fabrication of various type of nanostructured biosensors able to detect them with high sensitivity and specificity. Among the available sensing mechanisms, the sensor technology based on Surface-enhanced Raman Spectroscopy (SERS) is frequently preferred for identifying nucleic acids. In these sensors, natural or synthetic oligonucleotide sequences, acting as probes to hybridize the target molecules, are immobilized on a plasmonic sensing platform. In particular, aptamers, short DNA/RNA sequences, are emerging as new recognition elements for their chemical stability and specificity. Here, we focus on the combination of a specific type of aptamer, a molecular aptamer beacon, and nanostructured SERS biosensors for a sensitive detection of nucleic acids. [ABSTRACT FROM AUTHOR]

Metastasis stands as the leading cause of mortality among colorectal cancer (CRC) patients. Galunisertib (LY2157299, LY) is a small molecule demonstrating promising anti-cancer effects by targeting the Transforming Growth Factor-beta (TGF-β) pathway. This route plays a pivotal role in initiating the epithelial-to-mesenchymal transition (EMT), a critical process for metastatic spread. Unfortunately, LY chronic treatment causes undesired effects. To mitigate these side effects, nanoscale drug delivery systems have emerged as a transformative approach in cancer treatment, enhancing drug effectiveness while minimizing toxicity. In this study, we introduce a hybrid nanosystem (DNP-AuNPs-LY@Gel) comprising porous diatomite nanoparticles decorated with plasmonic gold nanoparticles (AuNPs), encapsulating LY within a gelatin shell. This multifunctional nanosystem demonstrates efficient LY delivery, EMT reversal in CRC 2D and 3D cultures, and anti-cancer effects in vivo. Moreover, the nanosystem allowed the quantification with sub-femtogram resolution of the drug intracellularly released using surface-enhanced Raman spectroscopy (SERS). The release of LY is triggered by CRC cell acidic microenviroment. Real-time monitoring of drug release at the single-cell level is achieved by analyzing SERS signals of LY within CRC cells. The heightened efficacy of LY delivery through the DNP-AuNPs-LY@Gel complex offers a promising alternative strategy for reducing drug dosages and subsequent undesired effects. [ABSTRACT FROM AUTHOR]

In this study, we present an innovative optical biosensor designed for the precise detection of Interleukin-6 (IL-6), a crucial cytokine associated with various pathological conditions. Our biosensor is based on silicon porous material meticulously modified with a molecularly imprinted polymer (MIP), ensuring specific and sensitive recognition of IL-6 molecules. Fabrication process involves the electrochemical etching of silicon porous chips followed by the electrodeposition of MIP, tailored to selectively bind IL-6 targets. Through rigorous testing across a range of IL-6 concentrations, our sensor exhibits remarkable sensitivity, showcasing discernible optical responses proportional to the varying analyte concentrations. Furthermore, we assessed the sensor's performance using bovine serum, a complex biological matrix, to simulate real-world sample conditions. Encouragingly, the sensor maintains its selectivity and optical response in the presence of serum components, affirming its robustness and applicability in practical diagnostic settings. [ABSTRACT FROM AUTHOR]