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Description: TITLE: POLYDOPAMINE-GOLD NANOPARTICLE COMPOSITE MATERIAL SYNTHESIS BIA ENGINEERING CELLS
Abstract:

Increasingly, metallic nanoparticles are being used for biomedical, environmental, and industrial applications. Metallic nanoparticles, such as gold nanoparticles (AuNPs) feature prominently in plasmonics, biosensing, photoacoustic and photothermal imaging.

Polydopamine, which can lead to the formation of eumelanin is a biomolecule that has also gained lot of interest due to its broad absorption spectrum and has potential for optical, photo-acoustic, and biosensing applications. Formation of a biocomposite material combining such optically-active materials could lead to a tunable absorption spectrum, based on polydopamine thickness. As the complexity of composite materials increases, the development of simple design rules become essential, and using biological building blocks is one method to achieve this. Bacterial synthesis routes offer immense potential for an efficient synthesis process, ease of functionalization, modification and repeatability.

Genetically modified E. coli strains can synthesize extracellular curli nanofibers, which is an amyloid fibrous structural components present in biofilms. We have designed and assembled DNA constructs to produce curli fibers with the ability to reduce gold nanoparticles and a polydopamine-binding fusion protein. Two E. coli strains were transformed with the constructs to produce the melanin coated well-organized gold nanoparticles. Curli fibers were assembled with alternating structural curli CsgA (protein repeat unit) segments, where one of the CsgA units was conjugated to spy tag protein, and the other was conjugated to the peptide fragment (FlgA3), which has been shown to modulate gold nanoparticle reduction from auric chloride solution. A fusion protein comprised of the spycatcher protein conjugated to the repeat unit of the Pmel17 amyloid fiber was created, and the fusion lead to the formation of the gold nanoparticle-polydopamine conjugate. In this study we designed and produced novel polydopamine-bound gold nanoparticles using synthetic biology approaches, to generate a preliminary model for future investigation of the feasibility and advantages of bacterially-produced tunable biocomposite materials, which could find applications in plasmonics and catalysis.



Committee Members: Drs. Tracie Ferreira and Vanni Bucci, UMassD Bioengineering and Dr. Chia Suei-Hung, Director of
RXAS Dept. at Air Force Research Lab (AFRL).


All BMEBT students are encouraged to attend and all interested parties invited.

For further information, please contact Dr. Milana Vasudev by email mvasudev@umassd.edu.