Recently, a research titled “Fully Bioabsorbable Natural-Materials-Based Triboelectric Nanogenerators” was published in Advanced Materials by the team of Prof. Fan Yubo from Beihang University and the team of Academician Wang Zhonglin from Beijing Institute of Nanoenergy and Nanosystems of Chinese Academy of Sciences. They developed different types of fully bioabsorbable natural-materials-based triboelectric nanogenerators (BN-TENGs) from five natural biodegradable materials.
Fig. 1(a) Natural bioresorbable polymers (NBPs) originating from nature with wide raw material sources. (b) Structure diagram of a typical BN-TENG device. (c-d) Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images of nanostructure on the surface of NBP film. (e-j) Basic electric properties of BN-TENG.
Implantable medical devices for neurological and cardiovascular diseases must meet high requirements in size, stability and biocompatibility. Such devices at present are mainly powered by rechargeable or non-rechargeable batteries, which are subject to problems like internal heat, capacity loss, and battery failure. Once the service life of these batteries comes to an end, the patient has to receive a second surgery to remove them and face considerable mental and economic burdens.
An alternative solution is implantable triboelectric nanogenerator (iTENG). It attracts wide attention for its unique working mechanism (triboelectrification and electrostatic induction) and efficiency of energy conversion. iTENG can collect different forms of biomechanical energy, which may come from heartbeat, respiratory motion, limb movements and pulse pulsation, and convert them to electrical energy effectively. Many experiments have proven that the electrical energy can be applied to cardiac pacemaker, health monitoring as well as cell and tissue engineering.
In the recent research, the scientists tested different pairs among five natural materials (cellulose, chitin, silk fibroin, rice paper and egg white) and ranked the five according to their “triboelectric series”. Their work provided the research basis and data for materials selection and device design of BN-TENGs and other energy harvesters. Also, the BN-TENGs as a voltage source can be applied in the process of adjusting the beating rates of dysfunctional cardiomyocyte clusters, offering a new therapy for diseases like bradycardia and arrhythmia.
When the BN-TENGs implanted in Sprague–Dawley (SD) rats completed their mission, they can be fully degraded and resorbed in the rats. The BN-TENGs developed by the researchers have good biocompatibility, controllability and bioabsorbability. Besides, they feature high efficiency in terms of energy conversion from biomechanical energy to electrical energy, and can function normally and achieve controllable degradation by different ways of encapsulation in vivo and in vitro. There is great potential in them to power implantable medical electronic devices.
Reported by Hou Dandan
Edited by Song Chao and Li Mingzhu
Translated by Li Mingzhu