Detection of Dopamine by Fluorescent Optical Probes with Quantum Dots

Undergraduate #113
Discipline: Technology and Engineering
Subcategory: Biomedical Engineering

Ruth Holden - Norfolk State University
Co-Author(s): Min H. Kim, Alonzo Jenkins, and Hargsoon Yoon, Norfolk State University, VA

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Parkinson’s disease is a chronic, progressively disabling neurodegenerative disorder that occurs late in life, causing motor, autonomic, emotional, and cognitive symptoms. The number of persons with Parkinson’s disease (PD) worldwide is, conservatively, expected to nearly double by 2030. The improvement of microelectrode devices for neural sensing has increased the understanding of the central nervous system and its interactions with the body. Central to this research is the detection of neurotransmitters such as Dopamine (DA), an important biomarker in PD, at the neuronal level. While neuroprobes have been fabricated from various materials, many of these materials have been found to be lacking in biocompatibility, flexibility, and insolubility. The objective of our research is to utilize an optical fiber probe that has a small enough cross section to be inserted into the subcellular target area and operated in chronic performance. This probe needs to be biocompatible, flexible, yet strong. Our probe was augmented with quantum dots (QDs). The integration of QDs with biosensors takes advantage of the optical properties of QDs and a change in QD photoluminescence signals the presence of the target species. This property is effective for the detection of DA concentrations. Nerve cell immune responses are addressed by utilizing biocompatible and flexible material and the application of Nafion as a coating material. Dopamine HCl was added to a standard PBS solution and serial dilution was used to prepare different molarities of DA solution: 100µM, 10 µM, and 1 µM. One end of the optical probe was inserted into a microelectronics device fitted with a Blue LED as the light source- known frequency of 460nm. The optical fiber probe tip, with known QD fluorescence of 607nm (pinkish-red), was inserted into each of the solutions. Data analysis computer program captured the intensity. The result of the data analysis correlated the expected intensity of the specific molar solution and the PBS control solution. Data confirmed that the proposed identification of different DA concentrations could be achieved using QD-augmented optical fiber probes. Future work will address enhanced capability of QD fluorescence in detection of DA, calibration of data analysis, application of coating material (e.g. Nafion) to the tip of the probe to improve DA detection, and the increased capability of detecting DA at the nano-molar level (in vivo ranges).

Funder Acknowledgement(s): This research was supported by WBHR-LSAMP, NSF Grant #P204007.

Faculty Advisor: Hargsoon Yoon,