Metasurfaces for biomedical applications: imaging and sensing from a nanophotonics perspective

Abstract

Metasurface is a recently developed nanophotonics concept to manipulate the properties of light by replacing conventional bulky optical components with ultrathin (more than 104 times thinner) flat optical components. Since the first demonstration of metasurfaces in 2011, they have attracted tremendous interest in the consumer optics and electronics industries. Recently, metasurface-empowered novel bioimaging and biosensing tools have emerged and been reported. Given the recent advances in metasurfaces in biomedical engineering, this review article covers the state of the art for this technology and provides a comprehensive interdisciplinary perspective on this field. The topics that we have covered include metasurfaces for chiral imaging, endoscopic optical coherence tomography, fluorescent imaging, super-resolution imaging, magnetic resonance imaging, quantitative phase imaging, sensing of antibodies, proteins, DNAs, cells, and cancer biomarkers. Future directions are discussed in twofold: application-specific biomedical metasurfaces and bioinspired metasurface devices. Perspectives on challenges and opportunities of metasurfaces, biophotonics, and translational biomedical devices are also provided. The objective of this review article is to inform and stimulate interdisciplinary research: firstly, by introducing the metasurface concept to the biomedical community; and secondly by assisting the metasurface community to understand the needs and realize the opportunities in the medical fields. In addition, this article provides two knowledge boxes describing the design process of a metasurface lens and the performance matrix of a biosensor, which serve as a “crash-course” introduction to those new to both fields.

Chiroptical Metasurfaces: Principles, Classification, and Applications

“…It was also observed that an increase in the size of the unit-cells of a metasurface could lead to better sensing, especially if nanorods are used, due to their larger surface area. Chiral metasurfaces can also help in sensing DNA and cancer biomarkers, which make chiral metasurfaces a very exciting tool in the field of CD spectroscopy [ 115 ].…”

A THz graphene metasurface for polarization selective virus sensing

“…Conventional optical spectroscopic methods for virus identification rely on the use of fluorescent materials such as dyes to label the target biomolecules [ 5 , 3 , 6 , 7 , 8 ]. Lately, immunoassay based on localized surface plasmon resonances (LSPR) has been introduced to improve detection limit at nanoscale for both solution and substrate based metallic nanoparticles [ 2 , 9 ].…”

“…Their interaction with the biomolecules induce detectable spectral changes with considerably reduced sensing footprint [ [29] , [30] , [31] , [32] , [33] , [34] ]. Plasmonic metasurfaces are proposed for detection of low concentration of analyte [ 32 , [35] , [36] , [37] , [38] , [39] , 8 ]. Graphene have been extensively investigated for photovoltaics and energy storage applications [ 40 , 41 ].…”

Engineering tunability through electro-optic effects to manifest a multifunctional metadevice

“…Novel metasurface-based lenses are ubiquitous for biomedical applications, 12 such as endoscopy and wearable medical devices. 13 These are replacing conventional bulky optical lenses such as Fresnel micro-lenses and micro-grating, which have limited imaging quality, high cost, inadequate phase coverage, and integration difficulties. The noteworthy advancements in the development of metalenses are the wide eld-of-view, 14,15 high aspect ratio dielectric, 16 achromatic, [17][18][19][20] and tunable metalens.…”