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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.

Conjugated polymers (CPs) are upcoming optical contrast agents in view of their unique optical properties and versatile synthetic chemistry. Biofunctionalization of these polymer-based nanoparticles enables molecular imaging of biological processes. In this work, we propose the concept of using a biofunctionalized CP for noninvasive photoacoustic (PA) molecular imaging of breast cancer. In particular, after verifying the PA activity of a CP nanoparticle (CP dots) in phantoms and the targeting efficacy of a folate-functionalized version of the same (folate-CP dots) in vitro, we systemically administered the probe into a folate receptor-positive (FR+ve) MCF-7 breast cancer xenograft model to demonstrate the possible application of folate-CP dots for imaging FR+ve breast cancers in comparison to CP dots with no folate moieties. We observed a strong PA signal at the tumor site of folate-CP dots-administered mice as early as 1 hour after administration as a result of the active targeting of the folate-CP dots to the FR+ve tumor cells but a weak PA signal at the tumor site of CP-dots-administered mice as a result of the passive accumulation of the probe by enhanced permeability and retention effect. We also observed that folate-CP dots produced ~4-fold enhancement in the PA signal in the tumor, when compared to CP dots. These observations demonstrate the great potential of this active-targeting CP to be used as a contrast agent for molecular PA diagnostic imaging in various biomedical applications.

Abstract While histopathology of excised tissue remains the gold standard for diagnosis, several new, non-invasive diagnostic techniques are being developed. They rely on physical and biochemical changes that precede and mirror malignant change within tissue. The basic principle involves simple optical techniques of tissue interrogation. Their accuracy, expressed as sensitivity and specificity, are reported in a number of studies suggests that they have a potential for cost effective, real-time, in situ diagnosis. We review the Third Scientific Meeting of the Head and Neck Optical Diagnostics Society held in Congress Innsbruck, Innsbruck, Austria on the 11th May 2011. For the first time the HNODS Annual Scientific Meeting was held in association with the International Photodynamic Association (IPA) and the European Platform for Photodynamic Medicine (EPPM). The aim was to enhance the interdisciplinary aspects of optical diagnostics and other photodynamic applications. The meeting included 2 sections: oral communication sessions running in parallel to the IPA programme and poster presentation sessions combined with the IPA and EPPM posters sessions.

Abstract The complete surgical removal of disease is a desirable outcome particularly in oncology. Unfortunately much disease is microscopic and difficult to detect causing a liability to recurrence and worsened overall prognosis with attendant costs in terms of morbidity and mortality. It is hoped that by advances in optical diagnostic technology we could better define our surgical margin and so increase the rate of truly negative margins on the one hand and on the other hand to take out only the necessary amount of tissue and leave more unaffected non-diseased areas so preserving function of vital structures. The task has not been easy but progress is being made as exemplified by the presentations at the 2nd Scientific Meeting of the Head and Neck Optical Diagnostics Society (HNODS) in San Francisco in January 2010. We review the salient advances in the field and propose further directions of investigation.

Review paper and Proceedings of the Inaugural Meeting of the Head and Neck Optical Diagnostics Society (HNODS) on March 14th 2009 at University College London. The aim of our research must be to provide breakthrough translational research which can be applied clinically in the immediate rather than the near future. We are fortunate that this is indeed a possibility and may fundamentally change current clinical and surgical practice to improve our patients' lives.