1. Microbial Detection in Surface Waters Developing a Hydrogel-Based Biosensor for Escherichia coli and Cryptosporidium By Jarod Gregory, Jon Cannell, Dr. Lilit Yeghiazarian, & Dr. Vasile Nistor
Functionalize a cylindrical poly(N-isopropylacrylamide) (PNIPAM) hydrogel with the capability to capture O157:H7 E. coli and Cryptosporidium as a proof-of-concept for a real-time hydrogel biosensor
Objective
PNIPAM hydrogels are approx. 1.5 cm length x 4 mm diameter (top). Hydrogels are capable of adsorbing acriflavinium chloride ions (bottom) due to the negative charge of Laponite crosslinkers1,2
Results
488 nm
640 nm
Control
Sample
488 nm excitation images show acriflavine adsorption and 640 nm images detect secondary antibodies. The presence of secondary antibody fluorescence in the sample and not control indicates successful primary antibody attachment to the PNIPAM hydrogel.
1 cm
HYDROGEL
NH2
Alexa 647 label
Method
1. Allow PNIPAM hydrogel to adsorb acriflavinium chloride molecules out of acriflavine dye solution
Proof-of-concept for microbe detection by versatile PNIPAM hydrogels
New technological platform by adsorbing intermediate molecule to attach molecules or devices to the PNIPAM hydrogel
Impact
3. Verify primary antibody attachment by imaging of fluorescent-labeled secondary antibodies
2. Conjugate primary antibody to adsorbed acriflavinium chloride via amine-to-amine chemistry using homobiofunctional crosslinker glutaraldehyde
Acknowledgments to the NSF Research Experiences for Undergraduates Program (NSF Type-1 STEP Grant, Grant ID No.: DUE ) and the CCHMC Imaging Center
Thomas, P. C., Cipriano, B. H., and Raghavan, S. R. (2011). “Nanoparticle-crosslinked hydrogels as a class of efficient materials for separation and ion exchange.” Soft Matter, 7(18), 8192–8197.
Gregory, J., Riasi, M. S., Cannell, J., Arora, H., Yeghiazarian, L., Nistor, V. (2013). “Remote-Controlled Peristaltic Locomotion in Free-Floating PNIPAM Hydrogels.” Advanced Materials, Submitted for Publication.