Cells are the basic units of life. Developing sensing platforms for probing the spatiotemporal characteristics of functional molecules in/on living cells is one of the basic goals in understanding the intricate biological processes and identifying early disease signatures for clinical diagnosis, therapy and prognosis. In situ sensitive analysis and imaging of cellular functional molecules can provide spatially or temporally resolved information on these essential cellular molecules in a non-invasive manner, and this approach has emerged as a cornerstone solution in the quantitative and/or functional analysis of different types of cellular molecules by the combination of nanotechnology and biotechnology with chemistry, biology, physics, engineering and medicine. With the achievements of nanotechnology, a wide variety of nanoscale materials have been used for the design of nanoprobes and biosensing nanodevices with lower cytotoxicity, high sensitivity and long-term stability, and a large number of research papers related to this topic have been published. Hence this cross-cutting research field has become one of the hottest topics in analytical chemistry, biosensing, nanoscience and biomedicine.

To offer researchers, especially beginners, a survey of the novel principles and detection strategies for the in situ analysis of cellular functional molecules, this book introduces the tailor-made design of detection probes and schemes from a top-down perspective according to the unique characteristics of cellular functional molecules, based on our research experience. The latest methodological developments, including the enhancement of detection sensitivity and specificity, precision localization, the implementation of dynamic tracking and the acquisition of quantitative functional information for various important functional molecules are discussed in detail. These functional molecules include cell surface and intracellular glycans, intracellular mRNAs, microRNAs, proteins (telomerase, caspases, etc.) and reactive oxygen, nitrogen and sulfur species. Methods for the visualization of glycosylation, imaging of tumour microenvironments and visualization of dynamic intermolecular interactions within living cells are also covered. The focus is on how to achieve an assay in an in situ, sensitive and specific way.

The material is presented in 10 chapters, covering all the authors’ study topics of in situ analysis methodology. Some experts who obtained their PhD degrees in Ju's and Tang's groups or who are working in these groups participated in the writing of some chapters, namely Dr Haifeng Dong (Chapter 3), Dr Ruocan Qian (Chapter 4), Dr Jiangwei Tian (Chapter 5) and Dr Yunlong Chen (Chapter 6) in Ju's group, and Dr Ping Li (Chapter 7), Dr Xu Wang and Fanpeng Kong (Chapter 8), Dr Wen Gao and Zhenhua Liu (Chapter 9) and Dr Xilei Xie and Xiaonan Gao (Chapter 10) in Tang's group. We are very grateful to all these colleagues for their contributions.

This book is one of a sequence of books published by the first author (Huangxian Ju) or with the co-authors, including Electroanalytical Chemistry and Biosensing Technologies (Science Press, 2006, in Chinese), Bioanalytical Chemistry (Science Press, 2007, in Chinese), Electrochemical Sensors, Biosensors and Their Biomedical Applications (Elsevier Academic Press, 2007, in English, and Chemical Industry Press, 2009, in Chinese), NanoBiosensing – Principles, Development and Application (Springer, 2011, in English, and Science Press, 2012, in Chinese), Nucleic Acid Detection: Methods for Analysis of DNA and MicroRNA (Intellectual Property Press, 2015, in Chinese) and Immunosensing for Detection of Protein Biomarkers (Elsevier, 2017, in English).

This book provides a comprehensive overview for a broad audience in academia and professionals working on different aspects of cellular analysis and cell biology. It is hoped to bridge the common gap between the research literature and new research ideas to develop the methodology for the in situ sensitive analysis of cellular functional molecules. We believe that it will be of great interest to readers and researchers in the fields of analytical chemistry, cell biology, clinical laboratory studies, clinical medicine and oncology. We are fortunate to have had the opportunity to undertake this important project. We warmly acknowledge the gracious support of our families. Finally, we thank the publishers for doing a remarkable job on this book.

Huangxian Ju, Nanjing, China

Bo Tang, Jinan, China

Lin Ding, Nanjing, China