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Temperature is a basic parameter influencing the behavior of systems in physics, chemistry and biology. From living cells to microcircuits, a wide range of cases require thermometry techniques that can be applied to reduced areas, offering sub-micrometric resolution and high accuracy. Since traditional thermometers cannot be applied in such systems, alternative tools have been specifically designed to measure temperature at the nanoscale; including scanning thermal microscopy, non-contact optical techniques or various types of luminescent nanoparticles. Each option presents interesting advantages, but also limitations that need to be considered and understood. We provide here an overview of the main currently available nanothermometry tools, discussing their pros and cons toward potential applications. [ABSTRACT FROM AUTHOR]

Biofilm formation is facilitated by cell–cell communication processes known as quorum sensing, which enable collective behavior and metabolic coordination. Surface topography and chemistry play a significant role in bacterial adhesion and biofilm formation, yet methods for monitoring quorum sensing in situ suffer limitations. Herein we suggest the use of surface-enhanced Raman scattering to study the effects of surface topography and chemistry on quorum sensing signals involved in biofilm growth. [ABSTRACT FROM AUTHOR]

The cell possesses the remarkable ability to perceive and process chemical and physical stimuli, which in turn modulate cellular behavior. One of the great wonders about nanotechnology is that it enables the fabrication of tools on the same length scale as biomolecules, thereby providing us with a unique handle for characterizing and controlling basic cellular processes. Owing to their tunable size and shape dependent physical properties, biocompatibility and facile surface modification, gold nanoparticles become potentially powerful tools to probe fundamental aspects of cell biology. Consequently, innovative approaches based on gold nanoparticles are under development toward the manipulation of cell function and improvement of techniques currently used in biomedicine and biotechnology. In this review we provide an overview of recent applications based on gold nanoparticles and nanostructured materials for the modulation of cellular activity and behavior, mediated by their interactions with cell surface receptors. [ABSTRACT FROM AUTHOR]

Highlights: [•] Enzymatically-produced thiocholine modulates the seeded growth of gold nanorods. [•] Acetylcholinesterase activity can be correlated with different nanoparticle shapes. [•] Subnanomolar detection of paraoxon and other nerve gas analogs is achieved. [ABSTRACT FROM AUTHOR]

Summary: The fabrication of highly optically active supercrystals of anisotropic nanorods exploiting the electric field concentration and the nanoantenna effects provides a new family of optical sensors with the potential to maximize the SERS signal and thereby the possibility of detecting and quantifying the disease markers with low SERS cross-sections at ultralow concentrations. The capabilities of the new self-assembled nanorod SERS substrates have been demonstrated for real-time sensing of prions in real blood. It may also be possible to functionalize the top layers of supercrystals with specific recognition molecules for sensing many other disease markers, or even its integration into on-line devices, for the ultrasensitive screening of analytical targets relevant to medical science, environment, and homeland security. [ABSTRACT FROM AUTHOR]

Abstract: Recent reports have illustrated the promising potential of chiral metal nanostructures, which exploit the characteristic localized surface plasmon resonance of metal colloids, to produce intense optical activity. In this article we review the concepts, synthetic methods, and theoretical predictions underlying the chirality of metal colloids with a particular emphasis on the size range of 10–100 nanometers. The formation of individual colloidal nanoparticles with a chiral morphology and a plasmonic response remains elusive; however, collective chirality and the associated optical activity in nanoparticle assemblies is a promising alternative that has seen a few recent experimental demonstrations. We conclude with a perspective on chiral nanostructures built up from achiral anisotropic metal particles. [Copyright &y& Elsevier]

Summary: This communication refers to the design of a novel, highly efficient and uniform substrate for SERS. The method takes advantage of the block copolymer micelle nanolithography concept for making well-ordered and uniformly spaced gold nanodot assemblies, which are subsequently used as seed substrates for chemical growth, thereby yielding Ag nanoparticle arrays containing a high density of hot spots, which render these concentrated island films ideal substrates for reproducible surface enhanced Raman scattering (SERS) detection. [Copyright &y& Elsevier]

Summary: Recent progress in nano-optics has paved the route toward the development of highly sensitive and label-free optical transducers using the localized surface plasmon resonance (LSPR) of metal nanostructures. In this review we describe the basis behind LSPR sensing and summarize the latest progress regarding nanostructure fabrication techniques and biosensing applications. Direct colorimetric assays reaching sensitivities in the zeptomolar range, or miniaturized multiplexed sensors constitute cutting-edge research in the LSPR biosensing field. We finally discuss the challenges that LSPR biosensors should face in order to be used in the near-future as commercial devices. [Copyright &y& Elsevier]

Nanocrystalline Materials provides a good insight for newcomers to the field, with well arranged, if sometimes overlapping, chapters and some notable absences in certain subject areas. [Copyright &y& Elsevier]

[Display omitted] Multicompartment nanoparticles have raised great interest for different biomedical applications, thanks to the combined properties of different materials within a single entity. These hybrid systems have opened new avenues toward diagnosis and combination therapies, thus becoming preferred theranostic agents. When hybrid nanoparticles comprise magnetic and plasmonic components, both magnetic and optical properties can be achieved, which are potentially useful for multimodal bioimaging, hyperthermal therapies and magnetically driven selective delivery. Nanostructures comprising iron oxide and gold are usually selected for biomedical applications, as they display size-dependent properties, biocompatibility, and unique physical and chemical characteristics that can be tuned through highly precise synthetic protocols. We provide herein an overview of the most recent synthetic protocols to prepare magnetic-plasmonic nanostructures made of iron oxide and gold, to then highlight the progress made on multifunctional magnetic-plasmonic bioimaging and heating-based therapies. We discuss the advantages and limitations of the various systems in these directions. [ABSTRACT FROM AUTHOR]

Materials scientists have performed exceptional accomplishments in the design of various types of materials that can be directly used for biomedical research. In particular, nanomaterials (including plasmonic nanoparticles) have become forefront scaffolds for designing bioactive materials. The application of such materials in biomedicine however requires a directed design providing actuation and stability in a particularly complex environment such as living organisms. Enhanced diagnostic tools for diseases such as cancer and HIV are pursued, and in this context nanoparticles offer exclusive physicochemical features for accurate biosensing, as well as actuation. We discuss the biosensing capabilities of plasmonic nanoparticles, in connection with SERS imaging. Novel therapies based on local drug delivery and photothermal therapy activated by nanoparticles are being explored. These applications are briefly discussed in this article, considering the actual biological problems faced by materials scientists and highlighting the beneficial interactions between materials science and biomedicine, which lead to novel routes in biomedical research and practice. [ABSTRACT FROM AUTHOR]

Abstract: Research on metal nanoparticles has been boosted by a wide variety of applications that often require a precise definition of the morphological features at the nanometer scale. Although the preparation (often based on colloid chemistry) of metal nanoparticles with many different shapes and sizes has been developed and optimized for spheres, rods, cubes, platelets and other shapes, the last few years have seen a rising interest in branched morphologies. This review article describes the main synthetic processes for the fabrication of such branched nanoparticles, often termed as nanostars, as well as some of the principal applications that have been found. A special emphasis is given to optical properties related to localized surface plasmon resonances and surface enhanced spectroscopies, for which nanostars have been predicted and demonstrated to shine brighter than any other shapes, thus opening new avenues for highly sensitive detection or biolabelling, among other applications. [Copyright &y& Elsevier]

As a natural response to a stressful situation, the human body produces cortisol. For this reason, cortisol is also called "the stress hormone" and is considered to be the principal stress biomarker. Although cortisol response to stress is essential for survival, abnormal levels in biological fluids may represent serious health risks. In this work, we present a cortisol biosensor which relies on a highly sensitive technique (surface-enhanced Raman spectroscopy, SERS) and a specific recognition (immunoassay). Gold nanostars were used as SERS nanotags, since they provided a better response than nanorods or nanospheres. Using the same concept, two different immunoassay modalities were evaluated, using either magnetic beads or gold-coated glass slides decorated with cortisol antibodies as the capture substrates. The magnetically-assisted SERS immunoassay presented a better performance and was therefore selected to quantify cortisol content in biological fluids (urine and serum). Significant advantages of this assay were found over standard methods such as Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) and Enzyme-Linked Immunosorbent Assay (ELISA), including higher sensitivity and repeatability, minimum sample preparation, simplicity, and portability. Therefore, the proposed SERS immunoassay might be implemented as a highly efficient tool for in situ monitoring of human stress levels and cortisol-related disorders (e.g. Cushing's syndrome and Addison's disease). Rational design of a surface-enhanced Raman spectroscopy-based biosensor to monitor cortisol in biological fluids. Image 1 • A novel cortisol biosensor relies on high sensitivity of SERS and specificity of immunoassay. • SERSI may use either magnetic beads or gold-coated glass slides as the capture substrates. • The magnetically-assisted SERSI was selected to quantify cortisol content in biological fluids (urine and serum). • This assayover-performs standard methods such as UPLC-MS and ELISA. [ABSTRACT FROM AUTHOR]