Introduction to materials chemistry of fluorescence bioimaging

Sijie Chen

Sijie Chen received her BSc degree in biology from Wuhan University in 2009 and PhD in bioengineering from Hong Kong University of Science and Technology (HKUST) in 2013. Subsequently, she took a postdoctoral position at HKUST, followed by an Endeavour Fellow position at the University of Melbourne. In late 2015, she joined the Karolinska Institutet (KI) as a Postdoctoral Fellow. Between 2017 and 2023, she served as an assistant professor at Ming Wai Lau Center for Reparative Medicine, KI. In August 2023, she moved to the Chinese University of Hong Kong, where she currently holds the position of Vice-Chancellor Associate Professor. Chen’s research focuses on fluorescent biosensors and fluorescence imaging. Her current interests include the development of novel luminescent materials for mechanobiology and regenerative medicine studies. She has published more than 90 research papers and has an h-index of 44.

Tony D. James

Tony D. James is a professor at the University of Bath and Fellow of the Royal Society of Chemistry. He has developed a broad interdisciplinary approach to research, with an underpinning focus on the development of modular sensors, where he has pioneered a range of reporting regimes. His research interests include many aspects of supramolecular chemistry, including molecular recognition, fluorescent sensor design, fluorescence imaging, chiral recognition, saccharide recognition, anion recognition, probes for redox imbalance and theranostic systems. He received his BSc from the University of East Anglia (1986), PhD from the University of Victoria (1991), and was a Postdoctoral Research Fellow in Japan with Seiji Shinkai (1992–1995). He was awarded a Royal Society University Research Fellowship at the University of Birmingham (1995–2000) before moving to the University of Bath in 2000. He was a Royal Society Wolfson Research Merit Award holder from 2017 to 2022. He has published over 500 publications in international peer reviewed journals, has a h-index of 96 and has been listed by Clarivate as a Highly Cited Researcher since 2022.

Apurba Lal Koner

Apurba Lal Koner has been a professor at the Indian Institute of Science Education and Research, Bhopal, India, since 2024. Previously he received a PhD from Jacobs University Bremen, Germany, with Prof. Dr Werner M. Nau, before moving to the University of Oxford, UK, as a Welcome Trust Postdoctoral Researcher and then as a Human Frontier Science Fellow. Koner’s research involves supramolecular photochemistry, synthesis and characterisation of fluorescent nanoparticles and fluorescence microscopy.

Ben Zhong Tang

Ben Zhong Tang is X. Q. Deng Presidential Chair Professor at the Chinese University of Hong Kong, Shenzhen. Tang received his BS and PhD from the South China University of Technology and Kyoto University, respectively, before conducting postdoctoral research at the University of Toronto. He joined HKUST as an assistant professor in 1994 and was promoted to chair professor in 2008 and is now a Distinguished Visiting Professor. He has published over 2,300 papers and has been listed as a Highly Cited Researcher in Chemistry and Materials Science since 2014. Tang is spearheading the research on aggregation-induced emission (AIE).

Fluorescence imaging is a predominant method employed in biological and biomedical research. This powerful technique utilises fluorescent probes that emit light upon excitation, enabling non-invasive and real-time observation of specific targets within the living system. It assists researchers in localising specific proteins in tissue, visualising subcellular structures, studying cell organisation, monitoring the bio-microenvironment, and even conducting image-guided surgery. From fundamental biological studies to biomedical applications, fluorescence bioimaging continues to facilitate a more comprehensive understanding of the complex biological world and provide us with powerful tools for disease diagnosis or treatment. This themed collection aims to provide a platform for recent developments in this rapidly evolving field of fluorescence bioimaging.

Featured in this collection are a wide range of novel and innovative sensors and probes. Liu, Fang et al. (https://doi.org/10.1039/D4TB00400K) present three aniline-based squaraines for two-photon fluorescence bioimaging in plant cells, while Yin et al. (https://doi.org/10.1039/D4TB00478G) report a fluorescent probe for real-time lysosomal imaging of cysteine. del Mercato et al. (https://doi.org/10.1039/D4TB01047G) develop a sensor for the ratiometric optical detection of potassium ions in cellular processes, while Yoon, Liu et al. (https://doi.org/10.1039/D4TB00934G) present a naphthalene-based fluorescent probe that detects mercury ions via excimer formation. Peng et al. (https://doi.org/10.1039/D4TB01462F) exploit a urea bond cleavage reaction for fluorescent imaging of nitric oxide in cells, and Li, Wang et al. (https://doi.org/10.1039/D4TB01828A) dynamically image hydrogen peroxide in serotonergic neurons using a small-molecule fluorescent probe. To give just two more examples from many in this collection, Klausen, Bradley et al. (https://doi.org/10.1039/D4TB01786B) synthesise a tri-branched fluorogenic probe with binding ligands for the detection of specific Gram-negative bacteria, and Pérez-García et al. (https://doi.org/10.1039/D4TB01859A) functionalise silicon oxide microchips with BODIPY probes for sensing glutathione in living cells.

As well as sensing applications, the collection features many materials with therapeutic functions. Kwok, Lam, Tang et al. (https://doi.org/10.1039/D4TB01175A) synthesise an aggregation-induced-emission-based photosensitiser able to generate type I and type II reactive oxygen species, while Wang, Yu, Yu et al. (https://doi.org/10.1039/D4TB01650E) report a H₂O₂-responsive BODIPY photosensitiser for imaging tumors and type I/II photodynamic therapy. Jiang, Hu et al. (https://doi.org/10.1039/D4TB01840K) demonstrate the antibacterial efficacy of a supramolecular system based on guanidiniocarbonyl-pyrrole-functionalised cucurbit[7]uril, and Zhao et al. (https://doi.org/10.1039/D4TB02372B) utilise a donor–π–acceptor structure for antimicrobial therapy in wounds. Dutta, Koner et al. (https://doi.org/10.1039/D4TB00572D) develop an NBD-based small-molecule probe for understanding ER stress and ER-Golgi communication. Iyer et al. (https://doi.org/10.1039/D4TB01740D) report a small molecule with the ability to inhibit amyloid beta fibril formation, showing promise in the fight against Alzheimer’s disease.

The collection also highlights new mechanistic insights and design principles in fluorescent materials. Huang and Nishimura (https://doi.org/10.1039/D4TB01745E) find new insights in the effect of hydroxide groups on excited-state intermolecular proton transfer to discern between specific monosaccharides, while Lou et al. (https://doi.org/10.1039/D4TB01801J) show that distinguishing the cis and trans isomers of peptide-based probes can enhance transmembrane protein recognition. Isomerism engineering is used by Li, Zhao et al. (https://doi.org/10.1039/D4TB01847H) to tailor the properties of aggregation-induced emission luminogens with a cyano group, and by Ni et al. (https://doi.org/10.1039/D4TB01617C) to optimise a coumarin-based fluorophore for H₂S sensing. Gunnlaugsson, Henwood et al. (https://doi.org/10.1039/D4TB01905A) show that the number and positioning of triphenylamino moieties greatly affect the optoelectronic and aggregation properties of aromatic imides.

As well as cutting-edge primary research, progress in the field is showcased by several insightful reviews. Mishra and Mishra (https://doi.org/10.1039/D4TB01960A) summarise recent developments in the design and application of enzyme-response fluorescent probes for disease diagnostics, while Pal (https://doi.org/10.1039/D4TB01858C) highlights the contribution of DNA-based fluorogenic tension sensors to the field of mechanobiology. You, Chen et al. (https://doi.org/10.1039/D4TB01440E) review aggregation-induced emission probes for imaging organelles under oxidative stress, while Smith et al. (https://doi.org/10.1039/D4TB01281J) compare methods of steric protection for enhancing the performance of near-infrared fluorescent dyes. Finally, Dong, Zeng et al. (https://doi.org/10.1039/D4TB01835D) discuss how artificial intelligence is guiding the design of subcellular fluorescent probes.

This themed collection is dedicated to showcasing the latest advancements in all aspects of materials chemistry for application in fluorescence bioimaging. By bringing together cutting-edge research, from mechanistic insights for understanding fluorescence bioimaging to materials design of new innovative probes for therapeutic applications, the collection seeks to give a broad overview into interdisciplinary collaborations focusing on advancing fluorescence bioimaging techniques towards practical applications. We are pleased to highlight such exciting and timely innovations and hope this collection helps in inspiring future research.

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