Introduction to the Special Issue on Two-Dimensional Materials and Their Biophotonic Applications

Emerging two-dimensional (2D) materials have attracted considerable attention on applications in electronics, optoelectronics, batteries as well as biomedicine in recent years, due to their unique physicochemical properties. With the intrinsic fluorescence and photoacoustic properties, 2D materials have been used as biological imaging agents for cancer diagnosis. Due to the near-infrared (NIR) optical absorbance, large extinction coefficient as well as high catalytic efficacy, 2D materials–based photothermal and photodynamic therapies have achieved excellent anti-tumor therapeutic efficacy. 2D materials are endowed with ultra-large specific area for efficient surface chemical modification and drug loading, because of the puckered layer structure, and have been widely explored as a robust NIR-light controlled drug delivery nanoplatform. More importantly, many works show that the cytotoxicity and biological toxicity of 2D materials are inappreciable, and many 2D materials are degradable in vivo into nontoxic phosphate and phosphonate, therefore good for clinic application. Especially, there are many studies on the integrated treatments that are both diagnostic and therapeutic, i.e., theranostics. Despite decades of technical development, 2D materials are still in its infancy for biomedical applications, and 2D materials–based biophotonic applications still face some challenges in practical applications.

This special issue highlights the latest progress on 2D materials and their potential impacts on biophotonic applications and related research fields. Three review articles and four original research papers are selected. For example, Tongkai Chen et al. reviewed the recent breakthroughs of 2D black phosphorous as a versatile nanoplatform for biomedical applications.¹ Qingyu Lin et al. reviewed the research development of 2D materials–based Raman spectroscopy applications.² Zhimei Wei et al. comprehensively introduced biological nanofiber materials prepared by electrospinning for potential antibacterial applications.³ In addition, four original studies presented in this issue range from excellent near-infrared fluorescence probes^4,5,6 to rapid label-free SERS detection.⁷ Overall, they represent a series of works with different focuses not only on the emerging 2D materials nanotechnology, but also on their potential applications in biophotonics and related research fields. Therefore, we strongly recommend this special issue.

Han Zhang received his B.S. degree from Wuhan University, China in 2006 and Ph.D. from Nanyang Technological University, Singapore in 2010. He is currently a director of the Shenzhen Key Laboratory of 2D Materials and Devices, and the Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Shenzhen University, China. His current research focuses on the ultrafast and nonlinear photonics of 2D materials.

Meng Qiu received his Ph.D. from Institute of Chemistry, Chinese Academy of Sciences in 2013. He joined Prof. Han Zhang’s lab at Shenzhen University as a research fellow, and then joined Prof. Jong Seung Kim’s group at Korea University as a research assistant professor. He is currently an associate professor of Ocean University of China. His research interests focus on the design and synthesis of two-dimensional materials for biomedical applications.

Wei Tao received his B.S. from Huazhong University of Science & Technology, China in 2011, and his Ph.D. from Tsinghua University, China, in 2015. He held a Postdoctoral Fellowship at Harvard Medical School and Brigham and Women’s Hospital from 2016 to 2018. Subsequently, he was promoted to be Instructor in 2018. In 2020, his promotion to Assistant Professor gained approval from the Harvard Medical School Chairs. Prof. Tao’s research interest is in the development of functional biomaterials, revealing nano-bio interactions, and exploring their biomedical applications.