A group of researchers has introduced an innovative method for the autonomous arrangement of a thin amino acid layer with a structured alignment across a considerable expanse. This development showcases substantial piezoelectric potency, potentially enabling the production of biocompatible and biodegradable medical microdevices – including pacemakers and implantable biosensors – in the coming years.
Led by The Hong Kong University of Science and Technology (HKUST), a research team has innovated a method to autonomously assemble a thin layer of amino acids with a structured alignment across a significant surface area. This assembly exhibits notable piezoelectric potency, thereby paving the way for the potential fabrication of biocompatible and biodegradable medical microdevices – including pacemakers and implantable biosensors – in the foreseeable future.
A pioneering research team led by The Hong Kong University of Science and Technology (HKUST) has introduced an innovative technique for the self-assembly of a thin layer of amino acids with organized orientation across a substantial area. This assembly exhibits a significant level of piezoelectric strength, thereby potentially enabling the future production of biocompatible and biodegradable medical microdevices, including pacemakers and implantable biosensors.
The piezoelectric effect, which involves the reversible conversion between mechanical and electrical energies, holds physiological significance within living organisms. Piezoelectric charges generated by the human tibia during walking contribute to bone remodeling and growth. Furthermore, the piezoelectric potential in the lungs created during respiration could aid in binding oxygen to hemoglobin.
However, many existing piezoelectric materials are rigid, brittle, and some even contain toxic elements like lead and quartz, rendering them unsuitable for implantation in the human body. Amino acids as piezoelectric biomaterials present a promising alternative due to their inherent biocompatibility, reliability, and sustainability. Nonetheless, achieving aligned orientation at a scale sufficient for functional effectiveness has remained a longstanding challenge, posing a global academic hurdle for the past eight decades.
In response to this persistent challenge, a team led by Prof. Zhengbao YANG, Associate Professor in the Department of Mechanical and Aerospace Engineering at HKUST, has recently pioneered an active self-assembly strategy for tailoring piezoelectric biomaterial thin films through a combination of nanoconfinement and in-situ poling. This approach facilitates the autonomous self-assembly of biomolecules over a vast area while maintaining consistent orientation. Significantly, the team discovered that films made from a particular amino acid, β-glycine, demonstrated an elevated piezoelectric strain coefficient of 11.2 pmV−1, the highest among other biomolecular films.
These self-assembled piezoelectric biomolecular films have the capacity to generate electrical signals when subjected to mechanical stress resulting from actions such as muscle stretching, breathing, blood flow, and minor body movements. Requiring no batteries, these films will simply dissolve within the body once their purpose is fulfilled.
Prof. Yang remarked, "Our study demonstrates a uniformly high piezoelectric response and excellent thermostability across the entire β-glycine films. The remarkable output performance, inherent biocompatibility, and biodegradability of the β-glycine nanocrystalline films hold practical implications for high-performance transient biological electromechanical applications, including implantable biosensors, wireless charging power supplies for bioresorbable electronics, smart chips, and other biomedical engineering applications."
The team's future endeavors include enhancing the film's flexibility to match biological tissues and achieving cost-effective mass production of bioresorbable piezoelectric films. Additionally, they plan to conduct in vivo experiments on animals to showcase the biomedical applications.
This collaborative study involved researchers from City University of Hong Kong and the University of Wollongong in Australia. The research findings were recently published in Nature Communications.
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