"펄스파워를 적용한 비침습 약물 전달기 개발 및 마우스 모델로의 적용"

함휘찬,김규식,이지환,최영진,김도년,여재익 한국전기전자학회 2024 전기전자학회논문지 Vol.28 No.1

"일부 약물은 피부의 표피층 이하로 주입될 때 훨씬 더 효과적인 의료 효과를 제공할 수 있다. 그러나 전통적인 비침습 주입 장치는 피부의 한 부분에 상대적으로 많은 양의 약물을 전달하며, 이는 조직층 구조를 분리하여 멍과 출혈을 유발할 수 있다. 피부의 큰표면적에 빠른 반복율로 소량을 주입함으로써 환자의 부상과 통증을 감소시킬 수 있다. 이를 위해서 약액을 분사하는 압력은 빠른속도로 침투 가능 압력까지 상승되고 빠르게 하강하여 주입되지 않는 되튀김량을 줄이고, 주입량을 최소화해야한다. 이러한 형태의비침습 주사 장치가 개발되었지만 그 장치들의 의학적 효능은 분석된 바가 거의 없다. 따라서 이 연구에서는 속도가 ~310m/s인마이크로젯을 분사하는 레이저 유도 마이크로젯 장치를 개발했다. 펄스 시간은 400~800 μs이며 각 분사가 초당 10번 반복되는 속도로 약물을 약 1 μL 분사할 수 있습니다. 이러한 원리를 사용하여 우리는 마우스 모델에 대한 약물 주사의 효과를 평가했다. 마우스 모델에 인슐린 용액을 주입한 후 혈중 인슐린 농도를 측정하였으며, 일반 바늘 주사 주법과 동일한 값을 얻었다." "Some drugs can offer far better medical effectiveness as it is injected through the intradermal layer of the skin, known as a needle-free injection. However, conventional needle-free devices might deliver a relatively large amount of drug in a just single spot of skin, splitting open the tissue layer structure, which might cause bruising and bleeding. By injecting the small volume with a fast repetition rate in a large surface area of skin, the patient may get much fewer injuries and pain. To achieve that specification, the driving force must be instantaneous and short-pulsed. Such a form of an injection device has been developed but the efficacy of those devices has been rarely examined. Therefore, this study developed the laser-induced microjet device that ejects microjet whose speed is ~310 m/s, during the 400~800 μs of pulse time. The device can eject ~1 μL of the drug at the rate at which each shot repeated 10 shots per second. Using this specification, we evaluated the efficacy of drug injection onto mouse models. After injecting the insulin solution into the mouse model, the blood insulin level is detected, resulting in 20 % of blood insulin level with the ordinary needle syringe injection method."

절연파괴 현상을 구동력으로 하는 마이크로젯 인젝터 개발

함휘찬(Hwi-chan Ham),김용현(Yong-hyun Ghymn),육승근(Seung-keun Yook),여재익(Jai-ick Yoh) 한국생산제조학회 2020 한국생산제조학회지 Vol.29 No.1

Drug delivery via microjets is a method that can potentially overcome the disadvantages of conventional needle injections. We implemented a microjet injection system that operates with spark-generated bubbles. The system consists of three components: a battery, power supply system, and microjet injector, which allows 10-20 discharges and microjet injections per second. In order to increase discharge efficiency, the circuit elements and electrode shapes were optimized and the flow inside the discharge chamber was operated to minimize the influence of metal colloids generated by electrode erosion. The microjet ejection was captured by a high-speed camera to correlate the energy of the spark discharge with microjet characteristics in order to make the system suitable for transdermal drug penetration.

Development and Application of Constant Flow Generating Injector with Pulse Energy Source as Driving Force

함휘찬(Hwi Chan Ham),장헌재(Hun Jae Jang),김영광(Young Gwang Kim),여재익(Jai Ick Yoh) Korean Society for Precision Engineering 2019 한국정밀공학회지 Vol.36 No.5

A pulsed-power source has the advantage of releasing a peak power over a short time interval. In this study, we implemented two types of such energy source, namely laser and dielectric break down power sources. We built the highpressure flow-output actuator utilizing such power sources in a micro-jet drug delivery system. We compared the jet speed from each power source and analyzed the drug penetration performance of the micro-jet injector. We found that hat the bubble growth rate caused by a dielectric breakdown power source per power input was three times faster than the laser power source. By using the micro-jet injector, we performed the insulin injection test using mouse models having diabetes mellitus to evaluate whether micro-jet injector has equivalent drug delivery performance when compared against conventional syringe-type injection.

쉬라우드가 장착된 풍력터빈 로터의 유입 유량 변동 특성 연구

김호현,함휘찬,이채연,유기완 한국풍력에너지학회 2016 풍력에너지저널 Vol.7 No.1

In this study, causes of increasing the mass flowrate for the shrouded horizontal axis wind turbine rotor were investigated numerically with comparing three shroud types, such as airfoil shroud and other two simple shrouds using constant thickness structure. Conical diffusers with and without the brim were used for other two simple shrouds. In particular conical diffuser with the brim was named wind-lens. The GOE 417 cambered airfoil with two angle of attacks, that is, 5° and 10° was used for airfoil shroud’s section. The flow field was assumed to be two-dimensional incompressible turbulent flow. The EDISON-CFD based on the LU-SGS for time marching and the Osher’s upwind scheme for spatial finite difference to solve the Reynolds-averaged Navier-Stokes equations was adopted to investigate the change of mass flowrates for various shrouds. Circulations around all of shrouds and pressure differences between inlet and outlet of the shrouds were calculated to investigate causes of increasing the mass flowrate. It turns out that the wind-lens is the best choice to maximize the mass flowrate for the given angles of attack of shroud’s section.

체크밸브 제어 레이저 유도 마이크로젯 약물전달 시스템

여재익,함휘찬,김용현,육승근 한국생산제조학회 2019 한국생산제조학회지 Vol.28 No.6

A microjet with a velocity of approximately 140 m/s and 150 μm diameter is injected into a narrow nozzle by a pressure wave delivered by laser-induced bubble expansion. The driving force of such an injector is a discontinuous pulse of a 10 Hz period. Every time a pulse ends, unnecessary air bubbles are introduced into the injector due to the decrease in its internal pressure. Such air bubbles interfere with the flow inside the injector, deteriorating its performance. Therefore, we developed a nozzle closure that reacts automatically to the driving force with a pulse shape. When the flow occurs, the nozzle is opened; when it does not, the nozzle is closed to prevent unnecessary air inflow. In this study, a microjet injector was applied to needle-free drug injection. We compared and analyzed the drug penetration performance of the injector with and without the nozzle closure attached to the injector.

레이저 유도 마이크로젯을 활용한 약물 전달 방식

장헌재(Hun jae Jang),함휘찬(Hwi chan Ham),여재익(Jai ick Yoh) 대한기계학회 2017 大韓機械學會論文集B Vol.41 No.7

경피를 통한 약물 전달 방식에 있어, 본 연구에서 제안하고 있는 바늘 없는 주사기 시스템은 레이저와 마이크로젯 인젝터로 구성 되어 있다. 이때 마이크로젯 인젝터의 핵심 메커니즘은 레이저 유도버블이다. 동력원으로 Nd:YAG와 Er:YAG, 두 종류의 레이저가 사용되었다. 버블의 특성을 결정짓는 레이저 변수인 펄스폭, 파장 등이 본 연구에서 고려되었다. Nd:YAG 레이저의 경우에 펄스폭이 버블의 생존 시간보다 짧기 때문에 캐비테이션에 가까운 버블을 형성하는 반면 Er:YAG 레이저의 경우에 펄스폭이 상대적으로 길고 물에서의 흡수가 잘 되기 때문에 보일링 버블이 만들게 된다. 버블 및 마이크로젯의 자세한 움직임은 초고속 카메라를 통해 촬영되었다. 이와 같은 과정을 통하여 마이크로젯의 특성이 버블에 의해 결정되는 것을 본 연구를 통해 관찰되었다. 약물 전달 성능은 기니어피그 조직에 형광물질을 침투한 결과로 부터 분석하였다. For transdermal drug delivery, needless injection system is composed of laser and microjet injector. Main mechanism of microjet injector is the laser-induced bubble. Nd:YAG and Er:YAG laser are used as a power source. Laser parameters such as pulse duration and wavelength are considered, which are core parameters to control the bubble motion. The Nd:YAG laser, pulse duration is short than bubble life time making cavitation like bubble while in Er:YAG laser, long pulse duration and high absorption in water drive bubble as a boiling bubble. Detailed motion of bubble and microjet is captured by the high speed camera. So it is observed that microjet characteristics are determined by the bubble behavior. The performance of drug delivery system is evaluated by fluorescent staining of guinea pig skin.

유한요소해석을 이용한 마이크로 분사 노즐 특성 평가

임동욱,최두선,김태민,박정래,박규백,함휘찬,김지훈,Lim, Dong-Wook,Choi, Doo-Sun,Kim, Tae-min,Park, Jung-Rae,Park, Kyu-Bag,Ham, Hwi-Chan,Kim, Ji-Hun 한국금형공학회 2020 한국금형공학회지 Vol.14 No.3

In the drug delivery system industry, the technology with even split injection becomes important for maximizing efficiency and minimizing the side effects. In conventional drug delivery system, infection can occur due to pain and splashing. Also, various applications are impossible due to disposable use, and it is the reason to avoid to use this system because of the complexity of the driving method. Therefore, in this study, a painless drug delivery device is developed for non-pain with electrical insulation breakdown method. Finite elements analysis was used to evaluate the ejection characteristics of drugs according to the shape of the micro ejection nozzle. The effect of the number of holes in the micro nozzle, the length of the nozzle and the inner shape of the nozzle on the drug discharge characteristics were analyzed.

분사 홀 개수에 따른 분사식 주사 시스템의 유동해석

김도언(Do-Un Kim),김지훈(Ji-Hun Kim),함휘찬(Hwi-Chan Ham) 대한기계학회 2019 대한기계학회 춘추학술대회 Vol.2019 No.11