Preface

Working on microfluidics over the past two decades and having co-founded four spin-off companies, I have experienced both the excitement and frustration that microfluidics could offer. The same experience has been encountered for droplet microfluidics, a branch of microfluidics, over the past decade. Although the scale and spectrum of research collaborations between droplet microfluidics and other disciplines are encouraging, it seems that the collaborations remain largely in publications and patents rather than facilitating droplet microfluidics to become an enabling tool, which has prompted the initiation of this book.

Droplet microfluidics holds tremendous potential to enable high throughput analysis that is in high demand in many areas such as life science research, drug discovery, personalized medicine and material synthesis. The vehicle of droplet microfluidics for high throughput analysis is monodispersed pico-to nano-litre sized drops that can be produced and manipulated at kHz rates in microchannel networks using one fluid to disperse another immiscible fluid. With numerous innovations reported and many spin-off companies established, the promised wide adoption of droplet microfluidics as an enabling tool has not been realized. Among the many contributing factors, the barrier between technology developers and application end users plays an important role. This book aims to draw contributions from both sides, especially the potential application areas, to foster an environment that encourages a dialogue between them and thus helps to break the barrier.

The book starts with a brief introduction of the history of the field evolvement and the challenges it faces currently (Chapter 1). Following this, the fundamentals and technology developments of droplet microfluidics are presented (Chapters 2 and 3, respectively) and a series of applications in life science research and biomedical applications are introduced. These applications include gene analysis (Chapter 4), single-cell gene analysis (Chapter 5), integrative functional analysis (Chapter 6), single-cell functional analysis (chapter 7), synthetic biology (Chapter 8), tissue engineering (Chapter 9) and manufacturing polymer particles (Chapter 10). The book ends with a discussion about the challenges and opportunities for droplet microfluidics to pave the way towards developing an enabling tool, which is provided from an industrial perspective (Chapter 11).

I owe enormous gratitude to the co-editor, Dr Abraham Lee, and all the contributors who are outstanding researchers and successful entrepreneurs in the field of droplet microfluidics across the world. I was very fortunate to work with all of them through editing this book. First, I am very grateful that Dr Lee, who is one of the pioneers and a world-renowned expert in the field of microfluidics and Lab-on-a-Chip technology, shares the same vision with me about the challenges and opportunities of droplet microfluidics and joined me to co-edit the book. Dr Lee has provided very valuable guidance on all the aspects of editing this book such as engaging outstanding contributors, structuring the book, as well as editing the chapters we are co-authoring. Second, I very much appreciate all the contributors for their hard work in providing high-quality contributions by accommodating many unexpected interruptions such as the pandemic. Third, I owe gratitude to Dr Michelle Carey and other colleagues from the Royal Society of Chemistry, who have been extremely supportive, patient and understanding throughout the book preparation. Last, but not least, Dr Pei Zhao's help in organizing and formatting the contributions is much appreciated.

C. L. Ren