In May of this year, a 5-year study was published in the main issue of Science. This is a cross-disciplinary research that the corresponding author Lei Ting has been working on since returning to China in 2018. When he returned to Peking University initially, he did not expect that this article would undergo 5 years of research, 3 rounds of reviews, and 1 round of major revisions. In the end, the paper presented in Science had a title consisting of only 3 words: N-type semiconducting hydrogel. Lei Ting believes that this research is an international first, and the 3 words are enough to highlight its innovation and breadth. "Publishing papers is not the most important thing; what's important is to build a cross-disciplinary platform." For this scientist who has returned to China for 6 years, "long-termism" is more worthy of belief.
A Paper with a Three-Word Title
In the spring of 2018, Lei returned to Peking University from the United States to serve as a distinguished researcher. Looking at the email address with the suffix "@pku.edu.cn," Lei couldn't help but reminisce about his undergraduate and doctoral studies at Peking University. Back then, he embarked on his research journey under the guidance of Professor Pei Jian from the School of Chemistry and Molecular Engineering. Now back in his homeland, Lei hopes to realize his new ideas at his alma mater and conduct some "out-of-the-box research." He set his sights on the intersection of three fields: chemical fundamentals, electronic devices, and biomedical engineering, hoping to find an ideal new material.
This new material must first be soft enough and biocompatible to adapt to human tissues. In the field of bioengineering, hydrogels like "jelly" meet these requirements, with hyaluronic acid injections being one application of hydrogels for beauty enthusiasts. However, traditional hydrogels lack the property of electronic conductivity and cannot capture weak electrical signals within the body like electronic devices.
In the first two years, Lei's team made significant progress in their research. They developed a special organic electronic material with superior structure and performance. The biggest issue was that this material could not function stably in water and could only be considered a disposable material. At that time, Lei's "first disciple" and the first author of the paper, Li Peiyun, tried numerous methods to enhance the material's stability, but neither light exposure nor heating could solve this problem.
It wasn't until November 2022 that Li Peiyun accidentally discovered that adding a water-soluble crosslinker containing an anion to the solution of the new material resulted in the precipitation of a gel-like solid. "This could be a hydrogel!" Lei keenly realized that this new type of material might possess properties of both a hydrogel and a semiconductor, holding broad application prospects in the field of biomedical engineering. However, at that time, this issue was hardly researched internationally, and Lei's team lacked the research background on hydrogels and the conditions for biological experiments.
To address this, Lei reached out to Professor Dai Xiaochuan's research group at Tsinghua University, Professor Lu Shixian's research group at Peking University, and Professor Zhu Jia's research group at the National Nanotechnology Center, engaging in animal experiments, cell experiments, and band calculation research, respectively.
Sun Wenxi and Li Peiyun, despite the close proximity of Tsinghua University and Peking University, face challenges conducting experiments across campuses. The lead author of this article, Sun Wenxi, explains that due to the high cost of experimental equipment, they often have to carry over 20 pounds of instruments to Tsinghua University's laboratory to set up experiments. This six-month-long endeavor has given their muscles a real workout.
In May of this year, the collaborative research was published in the journal Science. Unlike most papers published in top journals like CNS, the title of the Thunder Team's paper is particularly concise, consisting of only three words: "n-type semiconductor hydrogels."
"Three words are enough to highlight the essence of our work," Thunder confidently states. Before submission, the team also experimented with longer titles, but Thunder believed that as this was the first international study on semiconductor hydrogels, there was no need for complex adjectives to describe it. A longer title would only limit the originality and scope of the article.
Perhaps this echoes Shakespeare's famous quote: "Brevity is the soul of wit."
The research team of Thunder (front left four) celebrated their birthdays with a dinner party after three rounds of reviews, finally achieving success on their resubmission!
This groundbreaking study, filling an international research gap, faced a tumultuous review process. Initially rejected by the editorial board of Science, the paper was eventually accepted after significant revisions. In late June 2023, the Thunder team submitted their paper to Science for the first time. Just two weeks later, the editorial board initiated the review process. While one reviewer provided highly positive feedback, another suggested several modifications and granted a 6-week revision period. Shortly after, the Thunder team conducted additional experiments and resubmitted their work. Due to the interdisciplinary nature of the study, an additional reviewer was included in the second round of reviews. While one reviewer gave a favorable evaluation, the second reviewer introduced new perspectives. The feedback email for this round of review shockingly stated "Reject."
"At the beginning, I didn't dare to hope for publication. Just being able to submit was already a joy," shared Li Peiyun and Sun Wenxi. Despite their disappointment upon receiving the rejection letter, their mentor, Thunder, remained optimistic: "Reviewer comments are not necessarily negative. As long as the novelty and scientific rigor of the research are not questioned, there is still a chance for publication." After nearly two months of revisions, the team resubmitted their work for the third round of review. This time, all three reviewers from different disciplines acknowledged the interdisciplinary nature of the research, leading to the editorial board finally accepting the manuscript.
Upon publication, Thunder was pleasantly surprised to find that their study received commentary from both the editorial board and experts at Science. "The n-type semiconductor hydrogel created by Li et al. paves the way for in-situ computation at the bioelectronic-tissue interface, guiding research towards semiconductor functionalities in the next generation of hydrogel bioelectronics," remarked Science editor Marc Lavine and industry experts Dace Gao and Simone Fabiano. Furthermore, the editorial team at the prestigious interdisciplinary journal Nature Review Materials reached out to the team, expressing interest in featuring their work in a highlight article.
"In interdisciplinary fields, it's challenging to gain recognition from all experts, highlighting the importance of the work's quality," reflected Thunder.
In the classroom, there is a dynamic between the enthusiastic mentor, Thunder, and the diligent student, Sun Wenxi.
In the eyes of the students in the research group, mentor Thunder is a true "academic enthusiast." This outgoing scientist excels in communication and gains energy from academic exchanges. This is evident from Thunder's office. The Materials Science and Engineering College where he works is an emerging interdisciplinary institute. Due to limited office space, researchers and students are arranged to share the same office. The outer area of the office is occupied by students' workstations, just a few steps away from the mentor's office. Thunder's office is modest, with only a desk, chairs, and a small sofa. "Here, I can always communicate with my students promptly," Thunder explains. This office layout enhances efficiency, eliminating any sense of distance between mentor and students. On the other hand, student Sun Wenxi is more of an "academic introvert," not frequently engaging with teachers but preferring to communicate with the mentor through weekly reports. Fortunately, Thunder does not suffer from "academic procrastination." He responds to emails on his phone promptly, even providing feedback on time-consuming paper revisions within a week. Sun Wenxi recalls that when applying for a Ph.D., he sent over a dozen emails introducing himself, but only Thunder replied promptly, stating that there were Ph.D. slots available this year and arranging an online interview. To the students in the research group, this responsive mentor brings a sense of security to their academic journey.
Sun Wenxi reported progress at the international conference, "My classmates are all excellent and have more choices, so I need to show a positive attitude," Thunder chuckled. Although they shared the same office, the labs for chemistry, electronics, and bioengineering were scattered throughout the campus, creating a decentralized work environment that allowed for a more flexible pace within the research group. Thunder believed that each student should arrange their work according to their academic goals and aspirations. Research progress, Thunder said, should be driven by self-motivation. "Being in the same office as the advisor, I was a bit nervous at first," Li Peiyun said with a smile, but over time, I found that the advisor not only had no airs but also had a highly efficient communication style, where any issues could be promptly discussed and resolved. Currently, the college is arranging more spacious and independent offices for researchers, but Thunder still prefers to maintain the current mode of communication and is reluctant to leave this cozy little corner. Building connections upon returning to the country is more important than publishing a few papers.
Today, after studying and teaching at Peking University for 15 years, Thunder often gazes out the window in his small office, where lush green trees and the iconic grey-tiled red walls of Peking University can be seen. He often recalls the end of 2017 when he was a postdoctoral fellow at Stanford University in the United States, under the mentorship of the renowned academician Bao Zhenan. At that time, he had opportunities for positions at overseas universities and companies, but he ultimately decided to return to China, back to Peking University.
The Thunder (Front Left Six) Research Team's Commemoration of Teachers' Day 2023
In the eyes of Thunder, at the age of 31, he made a correct decision for three reasons.
First, the upward trend of scientific research development. In Thunder's view, the cross-disciplinary integration in various disciplines in China is still burgeoning, and the rapid growth of scientific research funding in China over the past 20 years has brought new opportunities for "cross-disciplinary scientists" like himself with backgrounds in chemistry and electronic devices planning to carry out bioelectronic applications.
Second, a well-established upstream and downstream industrial chain. "Since I came to the United States in 2013, I have observed the increasing departure of manufacturing industries, accompanied by the withdrawal of investors," Thunder sighed. For the materials and electronics industries, the upstream and downstream industrial chain is crucial. While China is "replacing the bird in the cage," it can ensure a sound manufacturing demand, allowing cutting-edge technology to move beyond the conceptual stage.
He cited an example: In 1987, Chinese scientist Qingyun Deng invented organic light-emitting diodes in the United States, with Japan being the first to achieve experimental screen production. The country that eventually achieved mass production was South Korea, which had a rich foundation in display device manufacturing at that time. Today, China has become the world's center for mobile phone manufacturing and a crucial manufacturing hub for electric vehicles, lithium batteries, and solar cells.
Third, an academic platform for "from 0 to 1." Observing the homepage of the Thunder research team, it is easy to see that the team has experienced a "period of explosive growth" in the past two years, with four achievements published in the first half of this year alone. However, Thunder believes that publication is not the most important; what matters more is the team's layout over the past six years. Since returning to China in 2018, the Thunder research team has attracted nearly 20 students, with about one-third majoring in chemistry, one-third specializing in device processing, and another one-third focusing on biomedical and other applied scenarios. For example, the first author of the latest Science paper, Peiyun Li, majored in functional materials at Huazhong University of Science and Technology, while Sun Wenxi's interests lie in device processing and biomedical engineering applications.
"Research emphasizes long-termism. Building an academic platform, choosing the right direction is far more important than publishing one or two papers," Thunder said.
References: https://doi.org/10.1126/science.adj4397 https://www.leigroup.cn/ (This article also contributed by reporter Wen Caifei)
