The advancement in intelligent and actuating systems has effectively been used in the medical field for diagnosis and drug delivery. It includes developing nano- or macro devices for accurately monitoring the biological environments and delivering the drug to the affected areas simultaneously. Thus, numerous synthetic biosensors and micromotors have been presented. Despite their remarkable success, their applications have not been fully explored owing to their low biocompatibility and biodegradability as they comprise mostly of exogeneous building blocks.
In a recently published literature, a living cell has exhibited the ability to sense and actuate different biological environments. Based on this phenomenon, incorporation of living cells into a single device with both sensing and actuation capabilities is highly desirable. Specifically, red blood cells are a good candidate for constructing living biosensors and micromotors due to their highly sensitive morphology to the environment. Additionally, red blood cells can be manipulated by optical forces which are an additional advantage.
Here, Prof. Yuchao Li, Dr. Xiaoshuai Liu, Dr. Xiaohao Xu, Prof. Hongbao Xin, Prof. Yao Zhang and Prof. Baojun Li from Jinan University constructed and assembled biocompatible living biosensors and micromotors from red blood cells for use in pH sensing and particle transport. The cells were optically bounded into a waveguide using fiber probes via the optical gradient force to ensure accurate pH detection. The light propagation mode of the waveguide and morphology of the red blood cells was compared and their dependence on the blood pH determined. The work is currently published in the research journal, Advanced Functional Materials.
The light propagation in the red blood cells waveguide was monitored and the pH of the blood solution detected in real-time with an accuracy of 0.05. This can be effectively used for diagnosing pH related blood disorders such as tumors considering that the pH of tumor tissues is relatively lower than that of normal tissues. After diagnosis, it was necessary to transport the microparticles to the target regions. This was completed by exerting an optical torque on the red blood cell waveguide to allow continuously rotate thus permitting effective transportation of microparticles.
Generally, the red blood cell biosensor and micromotor proved more effective in terms of flexibility and biocompatibility as compared to the synthetic sensors and motors. Consequently, they exhibited non-invasion properties in biological systems which is an added advantage in their biological applications. It was necessary to validate the application of the red blood cell by constructing it inside a zebrafish blood vessel. Interestingly, it was successfully assembled and operated hence showing its potential application in numerous areas.
In summary, Prof. Yuchao Li and his colleagues, for the first time, successfully created biocompatible biosensors and micromotors with the red blood cells and demonstrated its applications in pH sensing and particle transportation to the target location. Therefore, the living biosensors and micromotors will largely improve the medical field by providing a smart platform for precision biosensing, medical analysis and drug delivery.
Li, Y., Liu, X., Xu, X., Xin, H., Zhang, Y., & Li, B. (2019). Red-Blood-Cell Waveguide as a Living Biosensor and Micromotor. Advanced Functional Materials, 1905568.Go To Advanced Functional Materials