Progress, Opportunities, and Challenges of Magneto-Plasmonic Nanoparticles under Remote Magnetic and Light Stimulation for Brain-Tissue and Cellular Regeneration

Improving Sensitivity and Reproducibility of Surface-Enhanced Raman Scattering Biochips Utilizing Magnetoplasmonic Nanoparticles and Statistical Methods

Surface-enhanced Raman scattering (SERS) technology has been widely recognized for its remarkable sensitivity in biochip development. This study presents a novel sandwich immunoassay that synergizes SERS with magnetoplasmonic nanoparticles (MPNs) to improve sensitivity. By taking advantage of the unique magnetism of these nanoparticles, we further enhance the detection sensitivity of SERS biochips through the applied magnetic field. Despite the high sensitivity, practical applications of SERS biochips are often limited by the issues of stability and reproducibility. In this study, we introduced a straightforward statistical method known as "Gaussian binning", which involves initially binning the two-dimensional Raman mapping data and subsequently applying Gaussian fitting. This approach enables a more consistent and reliable interpretation of data by reducing the variability inherent in Raman signal measurements. Based on our method, the biochip, targeting for C-reactive protein (CRP), achieves an impressive detection limit of 5.96 fg/mL, and with the application of a 3700 G magnetic field, it further enhances the detection limit by 5.7 times, reaching 1.05 fg/mL. Furthermore, this highly sensitive and magnetically tunable SERS biochip is easily designed for versatile adaptability, enabling the detection of other proteins. We believe that this innovation holds promise in enhancing the clinical applicability of SERS biochips.

A Review of the Current State of Magnetic Force Microscopy to Unravel the Magnetic Properties of Nanomaterials Applied in Biological Systems and Future Directions for Quantum Technologies

Magnetism plays a pivotal role in many biological systems. However, the intensity of the magnetic forces exerted between magnetic bodies is usually low, which demands the development of ultra-sensitivity tools for proper sensing. In this framework, magnetic force microscopy (MFM) offers excellent lateral resolution and the possibility of conducting single-molecule studies like other single-probe microscopy (SPM) techniques. This comprehensive review attempts to describe the paramount importance of magnetic forces for biological applications by highlighting MFM's main advantages but also intrinsic limitations. While the working principles are described in depth, the article also focuses on novel micro- and nanofabrication procedures for MFM tips, which enhance the magnetic response signal of tested biomaterials compared to commercial nanoprobes. This work also depicts some relevant examples where MFM can quantitatively assess the magnetic performance of nanomaterials involved in biological systems, including magnetotactic bacteria, cryptochrome flavoproteins, and magnetic nanoparticles that can interact with animal tissues. Additionally, the most promising perspectives in this field are highlighted to make the reader aware of upcoming challenges when aiming toward quantum technologies.