1. Can you please briefly summarize the paper? 

Non-biodegradable implants have undergone extensive investigation as drug delivery devices to enable advanced healthcare toward personalized medicine. However, fibroblast encapsulation is one of the major challenges in all non-biodegradable implants, besides other challenges such as high initial burst, risk of membrane rupture, high onset time, non-conformal contact with tissues, and tissue damage. To tackle such challenges, we propose a novel ultrasoft and flexible balloon-type drug delivery device for unidirectional and long-term controlled release. The ultrasoft balloon-type device (USBD) was fabricated by using selective bonding between 2 polydimethylsiloxane (PDMS) membranes and injecting a fluid into the non-bonded area between them. The balloon acted as a reservoir containing a liquid drug, and at the same time, the membrane of the balloon itself acted as the pathway for release based on diffusion. The release was modulated by tuning the thickness and composition of the PDMS membrane. Regardless of the thickness and composition, all devices exhibited zero-order release behavior. The longest zero-order release and nearly zero-order release were achieved for 30 days and 58 days at a release rate of 1.16 μg/day and 1.68 μg/day, respectively. In vivo evaluation was performed for 35 days in living rats, where the USBD maintained zero-order and nearly zero-order release for 28 days and 35 days, respectively. Thanks to the employment of ultrasoft and flexible membranes and device design, the USBD could achieve minimal tissue damage and foreign body responses. It is expected that the proposed device may provide a novel approach for long-term drug delivery with new therapeutic modalities. We plan to validate the device with cancer disease model using potent anti-cancer clinical drugs for single and combinations therapies.

Future prospects: The potential applications for our developed device are broad, including long-term drug release in models of diabetes, epilepsy, and cancer. Our device fabrication technique, which utilizes selective bonding in a 2D plane, offers unique advantages. It allows for further integration of MEMS processing, enabling the fabrication of soft MEMS-based sensors. These sensors can serve as disease-specific biomarkers, such as pH, temperature, and pressure sensors, facilitating real-time monitoring at the target site.

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

I am not sure where to start, let me put it this way, as a mechatronics engineer specializing in flexible, stretchable, and wearable devices, my journey into the medical field began with clinical trials of my wearable device at Pusan National University Hospital. However, when the idea emerged to apply our soft MEMS based selective bonding techniques for a drug delivery device, we found ourselves entering a new territory of pharmaceutical and biological sciences.

The very first challenge commenced during long-term in vitro testing, spanning over five months and requiring meticulous sample collection. Transitioning to in vivo testing was even more challenging. As a mechatronics engineer, the prospect of performing surgical procedures on laboratory animals was daunting, especially considering my previous lack of experience in this area. I embarked on this steep learning curve, gradually familiarizing myself with laboratory animals and acquiring proficiency in surgical procedures along with histopathological analysis, IVIS imaging, and tissue extraction through self-directed learning and hands-on experience. I firmly believe that my self-motivation, perseverance, and unwavering desire to achieve played pivotal roles in attaining the current results. Moreover, the unwavering support and guidance from my esteemed mentor, Professor Sohee Kim, played a pivotal role in navigating through the complexities of the research process. Professor Kim's mentorship not only provided valuable insights but also fostered an environment of encouragement and efficiency, making the journey rewarding.

Despite the initial discomfort and lack of experience, this immersion in the world of animal trials provided invaluable insights into the practical application of implantable devices, complementing my engineering background.

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

I'm currently a PhD student at the NIMS (Neural Interface and MicroSystems) Lab within the Department of Robotics and Mechatronics Engineering at DGIST. Our lab specializes in the development of neural interfaces, including brain-robot interfaces, microdevices, and systems for implantation or attachment to the body for various healthcare applications like monitoring, diagnosis, treatment, rehabilitation, and basic research. My focus within this exciting field lies in the development of soft and flexible implantable drug delivery devices, as well as flexible, stretchable, and wearable sensors. When I initially joined the lab for my Master's course back in 2016, I had minimal exposure to this domain. However, the journey since then has been one of continuous learning and growth.

Under the guidance of my supervisor, I've had great opportunities to refine my study design, experimental techniques, and scientific writing skills. Their mentorship has been invaluable in elevating the quality of my research while allowing me the autonomy to explore and develop my own ideas. I'm also fortunate to be part of a supportive lab community and I want to thank them all from the core of my heart, where members have been incredibly helpful in aiding my transition and enriching my graduate student experience. Together, we're pushing the boundaries of innovation and contributing to advancements in healthcare technology.

DGIST is a relatively young research-oriented university with the ideology to advance science and technology through convergence of disciplines. It offers state-of-the-art research facilities and innovative laboratories led by expert faculty members. What sets DGIST apart is its commitment to supporting graduate students. With full scholarships available, the university eases the financial burden on students like myself, enabling us to fully immerse ourselves in our studies and research pursuits.

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

Since my arrival in Korea, my personal journey has been nothing short of extraordinary. Each day, I've experienced significant growth, both personally and professionally. Here, in this vibrant academic environment, I've truly learned the essence of research.

At my university, if you have the potential, the opportunities are endless. The institution provides unwavering support, ensuring that every resource necessary for research exploration is readily available. Whether it's access to cutting-edge equipment or opportunities for academic conferences and business trips, the university spares no effort in facilitating our research endeavors.

Moreover, I'm incredibly fortunate to have a professor who stands by me every step of the way. Her support knows no bounds, whether it's offering guidance on research projects or providing assistance with any challenges that arise. With such robust support systems in place, I'm able to fully immerse myself in my research without any distractions, allowing me to focus solely on pushing the boundaries of knowledge.

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

The scientific and technological landscape in Korea stands out on a global scale. With a plethora of universities offering diverse research specializations, prospective students have enough opportunities to explore labs aligned with their interests. I advise conducting thorough research to pinpoint the perfect fit.

Recently, the Korean government unveiled new regulations aimed at students, streamlining the process of acquiring Korean nationality. For those considering settling down post-graduation, Korea emerges as a top contender for residency.

Furthermore, esteemed institutions like DGIST extend full scholarships to graduate students. I encourage prospective applicants to stay informed about these scholarship opportunities and application deadlines. By doing so, they can devote their full attention to academic pursuits without the burden of financial constraints.

6. Future plan?

My journey through research and academia in Korea has ignited a profound aspiration within me: to serve as a Principal Investigator (PI) at a university or research center in this country. Having been privileged to receive education from esteemed institution here, I am driven to reciprocate through my own scientific contributions. But before embarking on this path, I am determined to undertake postdoctoral research in a leading university or institute abroad. This will allow me to further refine my skills and deepen my understanding of implantable drug delivery devices.

Furthermore, I am passionate about fostering better integration of foreign students within Korean workplaces. I firmly believe that the talented international students who receive education in Korea possess invaluable skills and insights that can greatly benefit this country. Facilitating their seamless integration into Korean enterprises holds immense potential for mutual growth and success.

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

Having been a student in Korea for over 7-8 years, I've had the privilege of witnessing Korea making remarkable strides in its scientific journey, I believe there is still much ground to cover. Regardless of nationality, we have the power to collectively push the boundaries of science forward. Korea has given us so much during our higher education journey, and it's our turn to contribute to making it one of the leading nations in scientific advancement. Together, we can conquer new frontiers in science and technology and ensure a brighter future for generations to come.