Magnetoplasmonic Nanomaterials for Biosensing/Imaging and in Vitro/in Vivo Biousability Van Tan Tran, Jeonghyo Kim, Lemma Teshome Tufa, Sangjin Oh, Junyoung Kwon, and Jaebeom Lee* Department of Cogno-Mechatronics Engineering, Pusan National University, Busan, 609-735 Republic of Korea ■ CONTENTS Magneto-Optical Biosensors B Magneto-Optical Surface Plasmon Resonance B Magneto-Optical Antennas D Magneto-Electrochemical Sensors D Magnetic Field in Electrochemistry D Magnetoplasmonic-Based Electrochemical Bio- sensors F Colorimetric Sensors G Enzyme-Based Biosensors G Non-Enzyme-Based Sensors G In Vitro/in Vivo Biousability and Bioimaging Applications I Magnetoplasmonic Therapeutics I Multimodal Imaging J Conclusions and Perspectives L Author Information L Corresponding Author L ORCID L Notes L Biographies L Acknowledgments M References M M ost commonly, magnetoplasmonic nanoparticles (Mag- Plas NPs) are unique composites combining magnetic and plasmonic materials within a confined nanoscale area that simultaneously show magnetic and plasmonic characteristics. They generally use Fe, Co, or Ni-based magnetic materials and noble-metal (e.g., Au, Ag, Cu, or Pt) plasmonic components, comprising a precious metal layer along a magnetic core or the inverse structure. MagPlas NPs are emerging multifunctional materials in the fields of nanoscale optoelectronics, anisotropic optics, electronics, optical sensing, and imaging. Their potential for sensing, targeting, and multimodal imaging is highly attractive for nanomedicine and nanobiotechnology. Because they possess suitable biocompatibility, 1 MagPlas NPs have also been used in biosensor systems, hyperthermia, 2 and magnetic resonance imaging (MRI) 3 applications. In addition, many researchers study MagPlas nanomaterials because no other technology can precisely control the locations of nanoscale materials at designated positions, except for magnetic NPs using external magnetic fields. In order to easily produce metamaterial films and novel self-assembled structures, acute control via dynamic external magnetic forces has recently emerged with the assistance of substrate-particle interactions and van der Waals forces. 4 Various MagPlas nanomaterials, i.e., core@shell, dimer, cluster, alloy, have been developed using different synthesis and fabrication techniques including coprecipitation, thermal decomposition, hydro/solvothermal, microemulsion, lithogra- phy, and so on. 5,6 Strategies of improving both sensitivity and selectivity for biosensors using these multifunctional MagPlas nanomaterials are attractive and have received considerable attention. The magneto-optical (MO) activity of MagPlas nanostructures has been shown to be greatly enhanced by plasmon resonance effect. 7 Chau et al. demonstrated that modulation of particle transparency is largely dependent on magnetic field in Co/Au core/shell microparticles due to spin- dependent interface effects. 8 The 3d transition ferromagnetic metals, such as Co, Fe and Ni, and ferrimagnetic metals and their alloys can also develop MO activity. 9,10 Novel magneto- optical surface plasmon resonance (MOSPR) sensors using a new type of transducer was demonstrated to yield improved sensitivity to refractive index changes of up to 2 orders of magnitude, compared to classical SPR assays. 11 Furthermore, localized surface plasmon resonance (LSPR)-based technolo- gies for label-free single-molecular detection are particularly attractive for biomedical applications. 12-14 Recently, magneto- plasmonic effects in nanostructures that support LSPR have attracted intensive study. 15,16 Regarding to electrochemical biosensing, the MagPlas NPs serving as active elements for the self-assembly, concentration, separation, and capture of analytes have been developed for enhancing the analytical detection. New concepts of electro- chemical biosensors using MagPlas NPs have been reported during past few years, including integrated magneto-electro- chemical sensor and electro-chemiluminescence (ECL) bio- sensor. 17,18 MagPlas NPs-integrated colorimetric biosensors also have enormous potentials for the simple and cost-effective in vitro diagnostic test platform. Magnetic and intrinsic enzyme-like activity of Fe-based NPs is highly attractive properties, which can be utilized for simple and robust biosensing strategies with the naked-eye detection or quantified by and inexpensive devices. Employing the novelty of MagPlas nanomaterials, our group has recently demonstrated novel magnetophoretic-based sensing strategies for rapid, ultrasensitive and early detection of Mycobacterium tuberculosis (TB) using gold NPs (as reporter) and magnetic particles (as separator). 19,20 Many studies using MagPlas nanomaterials and assembled structures thereof have focused on biomedical applica- tions. 21-26 Tomitaka et al. presented the contribution of magnetic core/Au shell MagPlas NPs to concentration- Special Issue: Fundamental and Applied Reviews in Analytical Chemistry 2018 Review pubs.acs.org/ac © XXXX American Chemical Society A DOI: 10.1021/acs.analchem.7b04255 Anal. Chem. XXXX, XXX, XXX-XXX Cite This: Anal. Chem. XXXX, XXX, XXX-XXX