A Tribute to Professor George M. Whitesides

Since its debut in 2010, Advanced Healthcare Materials (AHM) has been home to more than 2500 manuscripts from over 60 countries in the general areas of biomaterials, biointerfaces, biofabrication, tissue engineering, regenerative medicine, nanomedicine, and diagnostic devices for healthcare. In celebrating its tenth anniversary, the journal has decided to publish a series of special issues to honor some of the senior advisory board members for their strong support of the journal and for their outstanding contributions to the invention and development of advanced materials, devices, and technologies, with a major impact on human health. As the chairman of the editorial advisory board, it gives me the greatest satisfaction to organize this special issue to celebrate the pioneering and sustained contributions from Professor George M. Whitesides to many of the research topics covered by this journal. It also gives me the greatest honor to organize and contribute to this special issue as I received my academic training with Whitesides, first as a Ph.D. student and then as a postdoctoral fellow. All the other contributors also worked in the Whitesides lab as a student or a postdoctoral fellow. Amazingly, it is worth pointing out that none of us ever received any formal training in biological science but all of us ended up doing research related to biomedical applications. This drastic transformation can be traced back to the multidisciplinary research environment in the Whitesides group. As a matter of fact, the mentor himself has set an excellent example by showing us how to evolve from a hard-core physical organic chemist working on NMR and the Grignard reaction to a pioneer and expert of so many other research areas (there are too many to list here, for a brief glimpse, please refer to https://gmwgroup.harvard.edu/). Throughout his career, Whitesides has shifted to countless new research areas. As a rule of thumb, he only works in any particular area for about ten years. Once other people start to pour into an area, he will leave and look for new and more exciting problems to solve. As a trailblazer, he is able to break the grounds for so many research frontiers by repeatedly asking fundamental questions about problems that still seem to be intractable to everyone else. By design, every group member has to work on a number of different projects, eventually emerging as a generalist who will no longer be afraid of moving into new research areas. Another training we all received from Whitesides is related to scientific publishing (see the paper by him in Advanced Materials, article 0400767). In his own words: “If your research does not generate papers, it might just as well not have been done […] Interesting and unpublished is equivalent to non-existent.” With no exception, every paper from his group had to go through five to ten rounds of meticulous revisions by him, typically, on hard copies. No manuscript, whether it was for a journal with an impact factor of 30 or a journal with an impact factor of 3, could be submitted until it met his high standard in terms of both scientific content and writing. This special issue includes contributions from 20 alumni of the Whitesides group. Related to regenerative medicine, Joe Tien and co-workers review recent progress in the development of microfluidic biomaterials (2001028); Lara Ann Estroff and co-workers provide an account of their journey in exploring the multiple pathways for pathological calcification in the human body (2001271); Wilhelm T. S. Huck and co-workers demonstrate how microfabricated gaps can be used to reveal the effect of geometrical control in wound healing (2000630); Benjamin J. Wiley and co-workers report the fabrication of a high-strength hydrogel attachment through nanofibrous reinforcement (2001119); Gulden Camci-Unal and co-workers report on the use of mineralized hydrogels to induce bone regeneration in critical size cranial defects (2001101); Hongkai Wu and co-workers describe a biomimetic, nano-engineered platform for functional tissue engineering of cartilage superficial zone (2001018); Shuichi Takayama and co-workers describe the fabrication of mammary organoids with a basal-in phenotype through the use of a minimal gel scaffold that the epithelial cells self-assemble around and encapsulate (2000810); and Qiaobing Xu and co-workers report the use of bioreducible lipidoid nanoparticles for the delivery of mRNA capable of promoting the neural differentiation of human mesenchymal stem cells (2000938). In the context of nanomedicine, Younan Xia and co-workers highlight their own efforts in the development of nanobottles for controlled release and related applications (2000587); Bing Xu and co-workers report a strategy for selectively inhibiting cancer cells by leveraging trypsin-instructed self-assembly on endoplasmic reticulum (2000416); and Jinming Gao and co-workers demonstrate the use of tumor-targeted inhibition of monocarboxylate transporter 1 to improve T-cell immunotherapy of solid tumors (2000549). In the context of biosensing and diagnosis, John A. Rogers and co-workers report skin-interfaced microfluidic systems that integrate hard and soft materials for demanding applications in sweat capture and analysis (2000722); Xingyu Jiang and co-workers illustrate the use of a highly stretchable metal-polymer conductor electrode array for electrophysiology (2000641); David Walt and co-workers report a strategy for eliminating assay cross-reactivity by leveraging sequential protein capture in multiplex single molecule arrays (2001111); Joanna Aizenberg and co-workers report the application of inverse opal films as a medical sensing platform for the diagnosis of neonatal jaundice (2001326); Ralph Nuzzo and co-workers report the fabrication of biocompliant scaffolds for 3D cell culture and noninvasive sensing of cellular metabolites (2001040); and Daniel T. Chiu and co-workers leverage an enzymatic cascade reaction system to enhance the long-term stability of a glucose transducer based on a polymer dot (2001019). Related to biosurfaces and medical devices, Insung S. Choi and co-workers describe a systematic study of neuronal migration on silicon microcone arrays patterned with different pitches (2000583); Oliver Lieleg and co-workers report the development of a bioinspired dopamine/mucin coating to protect the surface of a medical device from wearing while providing lubricity and cell-repellent properties (2000831); and David Gracias and co-workers focus on the use of magnetic resonance to guide the navigation of untethered microgrippers (2000869). In the context of imaging, Lea Ann Dailey and co-workers investigate how PEG-PLGA matrices affect the in vivo optical/photoacoustic imaging performance and biodistribution of π-conjugated polymer contrast agents (2001089). And last but not least, Ravi S. Kane and co-workers demonstrate how to design vaccines by shielding the antigenic site Ø of a respiratory syncytial virus fusion protein immunogen (2000714). It is hoped that this special issue is able to provide the readers some representative and exciting snapshots regarding recent progress in the context of advanced healthcare materials. As interrupted by the pandemic, the preparation and submission of a number of invited manuscripts were delayed and unfortunately cannot be included in this special issue. It is hoped that the readers will enjoy the mix of topics presented in this issue and, most importantly, find the inspiration to push this important area of biomedical research to the next level of success. Younan Xia studied at the University of Science and Technology of China (B.S., 1987) and the University of Pennsylvania (M.S., 1993) before receiving his Ph.D. from Harvard University in 1996 with George M. Whitesides. He started as an assistant professor of chemistry at the University of Washington (Seattle) in 1997 and was promoted to associate professor and professor in 2002 and 2004, respectively. He joined the Department of Biomedical Engineering at Washington University in St. Louis in 2007 as the James M. McKelvey Professor. Since 2012, he holds the position of Brock Family Chair and GRA Eminent Scholar in Nanomedicine at the Georgia Institute of Technology.