Synthesis Methods and Optical Sensing Applications of Plasmonic Metal Nanoparticles Made from Rhodium, Platinum, Gold, or Silver

Nanomaterials for Photothermal Antimicrobial Surfaces

Microbial infection diseases are a major threat to human health and have become one of the main causes of mortality. The search for novel antimicrobial strategies is an important challenge for the scientific community, considering also the constant increase of antimicrobial resistance and the rise of new diseases. Among the new strategies to combat microbial infections, the photothermal effect seems to be one of the most promising. Hyperthermia is an effective and broad spectrum strategy for the removal of microbial infections. Among all of the strategies to reduce the diffusion of microbial infections, the preparation of antimicrobial surfaces seems of primary importance. In many cases, in fact, an infection can be diffused through surfaces just by touching them, or by inoculating microbes through an internalizable device, such as an implant, a prosthesis, or a catheter. In this review, we will summarize the recent advances in the preparation of photothermal antibacterial surfaces.

Strategies Employed to Design Biocompatible Metal Nanoparticles for Medical Science and Biotechnology Applications

The applicability of nanomaterials has evolved in biomedical domains thanks to advances in biocompatibility strategies and the mitigation of cytotoxic effects, allowing diagnostics, imaging, and therapeutic approaches. The application of nanoparticles (NP), particularly metal nanoparticles (mNPs), such as gold (Au) and silver (Ag), includes inherent challenges related to the material characteristics, surface modification, and bioconjugation techniques. By tailoring the surface properties through appropriate coating with biocompatible molecules or functionalization with active biomolecules, researchers can reach a harmonious interaction with biological systems or samples (mostly fluids or tissues). Thus, this review highlights the mechanisms associated with the obtention of biocompatible mNP and presents a comprehensive overview of methods that facilitate safe and efficient production. Therefore, we consider this review to be a valuable resource for all researchers navigating this dynamic field.

Immunomodulatory effects of copper nanoparticles against mitogen-stimulated rat splenic and thymic lymphocytes

In the present study, we have evaluated the effects of copper (Cu) nanoparticles (NPs) on the primary B-and T-lymphocytes proliferation, cytokine levels, and bio-distribution through in vitro, in vivo and ex-vivo studies to allow the possible exploitations of CuNPs in biomedical applications. CuNPs were characterized by UV-Visible spectroscopy, transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). The proliferative response of lymphocytes was studied by 3H-thymidine incorporation assay and lymphocyte viability through trypan blue assay. The bio-distribution of CuNPs into lymphoid organs was examined by using ex-vivo imaging system. Cytokine levels in plasma of control and CuNPs treated animal groups were determined by enzyme-linked immunosorbent assay (ELISA) method along with other biochemical analysis. CuNPs significantly suppressed the proliferation of primary splenic and thymic lymphocytes in a dose dependent manner. Ex-vivo imaging exhibited the distribution of CuNPs in spleen and thymus. Oral administration of CuNPs (2 mg and 10 mg/kg body weight) significantly inhibited the proliferation of splenic and thymic lymphocytes along with lowered cytokines levels (TNF-alpha and IL-2) on comparison with controls. The results indicated the significant inhibition of lymphocytes proliferative response and secretion of cytokines, thus unveiling the immunomodulatory effects of CuNPs.

Amplitude-Resolved Single Particle Spectrophotometry: A Robust Tool for High-Throughput Size Characterization of Plasmonic Nanoparticles

Plasmonic nanoparticles have a wide range of applications in science and industry. Despite the numerous synthesis methods reported in the literature over the last decades, achieving precise control over the size and shape of large nanoparticle populations remains a challenge. Since variations in size and shape significantly affect the plasmonic properties of nanoparticles, accurate metrological techniques to characterize their morphological features are essential. Here, we present a novel spectrophotometric method, called Amplitude-Resolved Single Particle Spectrophotometry, that can measure the individual sizes of thousands of particles with nanometric accuracy in just a few minutes. This new method, based on the measurement of the scattering amplitude of each nanoparticle, overcomes some of the limitations observed in previous works and theoretically allows the characterization of nanoparticles of any size with a simple extra calibration step. As proof of concept, we characterized thousands of spherical nanoparticles of different sizes. This new method shows excellent accuracy, with less than a 3% discrepancy in direct comparison with transmission electron microscopy. Although the effectiveness of this method has been demonstrated with spherical nanoparticles, its real strength lies in its adaptability to more complex geometries by using an alternative analytical method to the one described here.