Remarkable Progress on the On-Line Monitoring and Analysis of the Body Weak-Pressure by Zhang-Qi Feng’s Group

High-precision automatic extraction of human biological information has become a key link in the next generation of medical and biotechnology revolution. Measurement of absolute physiological pressure of the body can provide the basic basis for early diagnosis and postoperative follow-up of stress-related acute and chronic diseases, especially for patients with cardiovascular diseases and respiratory diseases.

Recently, Zhang-Qi Feng` research group from the School of Chemical Engineering has made a big step forward in on-line monitoring and analysis of body micro pressure. The study attempts to build a new strategy for prediction and real-time tracking of cardiovascular and respiratory diseases by in situ monitoring rhythmic pressure changing of cardiovascular and respiratory diaphragms.

The latest research results were published in the international top journal ADVANCED MATERIALS as of title “High-Performance Polyvinylidene Difluoride/Dopamine Core/Shell Piezoelectric Nanofiber and Its Application for Biomedical Sensors ", doctoral student Li Tong is the first author of this research paper.

High performance bioelectronic fiber and its application in monitoring physiological pressure in vivo.

The study developed a simple one-step strategy for fabricating core/shell PVDF/DA NFs based on the electrospinning method. Introducing appropriate amount of DA (1.0 wt%) would greatly facilitate the spontaneous formation and alignment of β-phase PVDF during the electrospinning process. This powerful self-assembly process was attributed to the formation of a ontinuous DA nanoshell around the PVDF NF core as a result of electrostatic repulsion amount charged DA molecules.

Strong intermolecular interaction between the -NH2 groups on DA and -CF2 groups on PVDF was believed essential to align the PVDF chains and promote nucleation of the β-phase PVDF. This continuous interfacial interaction was also believed to be able to improve the β-phase stability. The as-received PVDF/DA NFs exhibited superb piezoelectric property (d33 = −59.4 pm V–1) with excellent stability and biocompatibility. Flexible thin films composed of random stacking of PVDF/DA NFs were fabricated as piezoelectric sensors. This device could be conformally attached to various body surfaces (chest, neck, and wrist) providing an accurate reading of the weak mechanical stimulations from blood pulsations. This sensor device was also implanted on diaphragm in the abdominal cavity and on the femoral artery of mice to monitor the breathing patterns and arterial stiffness. It demonstrated a strong capability to accurately and rapidly detect the changes of diaphragmatic contraction and peripheral arterial walls when the mouse was at different physiological states.

At present, with the assistance of the Nanjing Jingling Hospital and the State Key Laboratory of Bioelectronics of Southeast University, the study has successfully completed a long term animal clinical research for two years, and established the systematic clinical test standards and biological environment parameters. The powerful function of the piezoelectric sensors can also offer great potential for the early assessment and prevention of cardiovascular diseases and respiratory disorders, as well as many pressure-related acute and chronic diseases (e.g., brain injury, hydrocephalus, tumor regeneration, glaucoma pulmonary tuberculosis, and even emphysema, etc.) More broadly, the piezoelectric PVDF/ DA NFs could be employed to harvest energy from alternative biological deformations (e.g., the beating of heart and the breathing of lungs, etc.) to produce useful electrical stimulation for tissue repair/regeneration and even disease treatment. This soft piezoelectric material and device design strategy will bring profound impacts to the development of smart biomedical electronics in regenerative medicine, drug delivery, and medical therapeutics.

This research achievement marks a solid step of the NJUST in the new research field of Bioinformatics and Bioelectronics and lays a foundation for the development of new frontier interdisciplinary. The research was supported by the National Natural Science Foundation of China, the natural science foundation of Jiangsu Province, and the Fundamental Research Funds for the Central Universities.