1. Can you please briefly summarize the paper? 

In this study, we isolated exosomes from pasteurized bovine milk and immobilized on polydopamine (PDA)-coated hyaluronic acid (HA)-based electrospun nanofiber (mEXO@PMAT). Although milk-derived exosomes (mEXOs) have been studied in various applications, miRNA profiles of mEXOs obtained from pasteurized milk, which have higher safety from potential infectious pathogens compared to raw milk, have not been well studied. Herein, we demonstrated that pasteurized milk-derived mEXOs contain various miRNAs playing key roles in anti-inflammation, cell proliferation, and collagen synthesis such as let-7b, miR-184, and miR-181a, resulting in elevated mRNA expression of keratin5, keratin14, and collagen1 in human keratinocytes and fibroblasts. The mEXOs encapsulated on PDA-coated HA nanofiber were gradually released over 14 days without burst-out effect. Owing to the presence of HA, which supports proliferation and migration of cells, the degree of in vitro cell migration increased remarkably in the mEXO@PMAT-treated HaCaT and HDF cells. In addition, the mEXO@PMAT provided significantly faster wound closure in vivo without notable toxicity. The considerably higher expression of keratinocyte-specific genes, collagen, interleukin, and VEGF genes in combination with the superior expression of CD31 and α-SMA in the regenerated wound tissues could harness the recovery effects of mEXO@PMAT. Based on these findings, we suppose that sustained liberation of mEXOs and HA from PMAT over 14 days can effectively enhance cell proliferation in vitro and accelerate wound healing in vivo, which could serve as a promising advanced wound-healing therapy.

2. Can you please tell us the main difficulties you had in the laboratory work and how you overcame them?

The most challenging work is the preparation of HA-based electrospun nanofiber. The electrospinning solution is water-based, which requires a tightly controlled electrospinning condition, especially the relative humidity which varies due to the change of season. To maintain the fibrous structure, the relative humidity should not be higher than 15%. In addition, we also need to optimize the crosslinking condition, so that the nanofiber can be gradually crosslinked and remain its original shape after crosslinking. High concentration of GTA can cause immediately shrinkage of the nanofiber. Throughout the process, the support and insights from my academic advisor and lab mates provided valuable guidance, and many trials were conducted to achieve these promising results.

3. Please introduce your laboratory, university or organization to bio-researchers in Korea.

I am doing the research at the Nano-Biomaterials Lab (http://nano-bio.kangwon.ac.kr/WordPress/) which is located at the Department of Medical Biomaterial Engineering, College of Biomedical Sciences, Kangwon National University, and led by Professor Hyuk Sang Yoo. With his deep passion, high motivation and dedication to the biomaterial research, our lab members are always encouraged to develop our own research skills and knowledge, supported to conduct the experiments in the most favorable conditions. Our research fields involve the fabrication of clinically-translational biomaterials with organic, inorganic, or hybrid materials for drug delivery, gene delivery and tissue engineering. To successfully complete this study, I also highly appreciate the collaboration and support from the Biomaterials and Biotherapeutics Lab at the Department of Bioscience and Biotechnology, Konkuk University, guided by Professor Hyejung Mok and Bioinspired Organic Materials Laboratory at the Department of Physics and Chemistry, DGIST, guided by Professor Seonki Hong.

4. Please tell us your experiences and your thoughts related to research activities abroad.

Studying and doing the research abroad is a challenge but also a valuable experience. I need to adapt myself not only with new techniques and research concepts but also various cultures and working styles in a multi-national lab. Thus, the work-life balance is very important to overcome the overall stress and ensure the productivity in a long term. The working environment here also fosters innovation and collaborative work in order to achieve a new milestone in the research.

5. Can you provide some advice for younger scientists who have plans to study abroad?

For the younger scientists who have plans to study abroad, to be well prepared in the mental and physical health are important to help us pursue our research for a long term. You should carefully choose the research fields that you are interested in and a lab that can really support your research activities. You should also be willing to step out of your comfort zone, open your mind to learn and adapt new knowledge and experience. There will be difficulties and challenges which may reduce our initial motivation, so well balancing our life and controlling our emotion is necessary to overcome any barriers. Adapting and building a good relationship with everyone in the lab also make us feel more comfortable when working in the same environment.

6. Future plan?

After completing my PhD program, I plan to continue the research career either in an academic institute or industry in the fields of nano-biomaterials. As a researcher, I need to continuously expand my scientific expertise and adapt with cutting-edge technologies, so I am opened to any opportunities which are matched my interests.

7. Do you have anything else that you would like to tell Korean scientists and students?

We should be open-minded, work hard and try our best, but know how to balance our life to ensure a long-term productivity.