Refine and shorten this essay to 350 words: From the summer vacation after grade 10 to the winter vacation in grade 11, I participated in the training program for iGEM competition, where I significantly developed my research skills and laboratory techniques. 

While brainstorming for the research topic, the teacher guided my teammates and me to think broadly about the problems people face. I recalled a boy in my class who had been absent for class for a long time, who turned out to have depression as we later knew. To understand the social relevance of depression, I led the team to design a questionnaire, with part of the questions for people who consider themselves as mentally healthy and the other part for those who had psychological issues. After analyzing the data, I found that many people who feel depressed did not go to the hospital for a diagnosis, mainly due to family disapproval and social stigma. Thus, I participated in creating a public service advertisement “It’s OK to not be OK” to combat the stigma surrounding depression, which was published on a major platform in China and received wide support from social media users. 	

Besides, we also researched the current way of depression diagnosis by interviewing a psychiatrist at the Shandong Mental Health Center. We discovered that the existing diagnostic method depends on the result of psychological questionnaires and objective judgment from the psychiatrist, which is time-consuming and sometimes inaccurate, hindering people from seeking help. To improve diagnosis, we decided to develop an efficient and accurate way for self-diagnosis. 

After the literature review, we found that some microRNAs are significantly up-regulated or down-regulated in the cerebrospinal fluid of major depression disorder patients. We focused on the amilCP, which is an up-regulated microRNA that could be transcripted to fluorescent proteins. We together conceived the design of a detector with a filter paper strip biosensor based on a toehold switch and cell-free system to diagnose depressive disorders by detecting specific microRNAs with assistance from the teacher. We synthesized three toehold switches and inserted them into the pET-28a expression vector, constructing these three recombinant plasmids. When they are transformed into E. coli, the miRNA can trigger the expression of the corresponding reporter protein. The teacher led us to make the test paper step by step, involving extracting the plasmid, amplifying DNA, constructing recombinant plasmids, and many other steps. In the process, sometimes I faced some challenges. For example, I was confused about how PCR works, but I asked the teacher and communicated with my teammates to figure out the problem. 

After we finally made the test paper, we did many experiments. However, I noticed that the sensitivities of 3 kinds of chromoproteins are relatively low. To make the results more noticeable, I persuaded the others to replace AmilCP with the lacZ gene to make the results more noticeable. 

All in all, the training for iGEM offers me a great chance to discover the problems in the surroundings and do my part to improve the conditions, with a attentiveness to others, a logical mind to analyze and skillful basic techniques for developing new things.