News Resource: School of Mechatronical Engineering

Editor: News Agency of BIT

Translator: Yuan Mengfan, News Agency of BIT

Recently, the important research progress of Professor Lou Wenzhong's research group from School of Mechatronical Engineering, BIT, on targeted therapy in hard-to-reach areas in vivo and application of hemostatic and bactericidal microsystems was published in Microsystems & Nanoengineering (impact factor 8.006), the top international journal of Nature. The related achievements were published under the title of "a micro explosive shock wave-based drug delivery microsystem for treating hard-to-reach areas in the human body". The first author of this work is Sun Yi, a Ph.D. student in School of Mechatronical Engineering, BIT, and the corresponding authors are Professor Lou Wenzhong and Dr. Feng Hengzhen. BIT is the first unit of this thesis.

Figure1 is a schematic diagram of delivering targeted drugs to lesions in vivo based on micro-area precise explosion shock wave.

Implantable targeted drug delivery microsystem can maximize local drug efficacy and reduce side effects to meet the treatment requirements. The internal organs of human body such as esophagus, gastrointestinal tract and respiratory tract have curved contours, and the ability of local administration with existing treatment methods is limited for intraluminal lesions. Targeted drugs can be sprayed into these hard-to-reach areas in the body to effectively improve the treatment effect (Figure 1).

Based on this, Professor Lou Wenzhong's team put forward a targeted drug delivery micro-system based on micro-area explosion impact jet, with an outer diameter of millimeter. A flexible rod at the tail can penetrate the targeted drug into the hard-to-reach area of the body, stimulate the nano-scale in-situ charge, and accurately jet the targeted drug to the focus area of the body. The kinetic energy of the targeted drug can be 3.2× 10-4 J. Through the optimization design of the system structure, the shock wave mainly propagates along the axial direction, greatly suppressing the radial vibration, and the nano-scale PDMS film in it can make the explosion. Micro-system action time is hundreds of microseconds, and there will be no temperature change (Figure 2).

Figure2 (a) Microsystem structure (b) Implantable targeted drug release (c) Changes of shell effective stress under shock wave

Furthermore, the team evaluated the feasibility and biosafety of targeted drug microsystem based on explosion shock wave injection through experiments (Figure3). For the first time, the semiconductor bridge and high-density explosive copper azide are integrated into flexible and rigid materials in three dimensions, and the theoretical and simulation inferences are verified by experiments.

Figure 3 Feasibility and biosafety verification

The related work of the research team was published at the 2021 International Summit μ-TAS (Micro-Chemical Analysis and Biological Analysis Conference), and the recruitment rate of the conference was 449/6000. Special thanks to Professor Zeng Qingxuan and Associate Professor Li Mingyu from School of Mechatronical Engineering, BIT, for their technical support in Process of copper azide.

Paper link:https://www.nature.com/articles/s41378-022-00441-8