Simultaneous Capture of Cryptosporidium parvum and Giardia lamblia in Surface Water Using Biofilm-Inspired Polydopamine Surface Functionalization

Abstract

Cryptosporidium parvum and Giardia lamblia are protozoan parasites that cause waterborne disease worldwide. Sensitive and cost-effective environmental monitoring methods are thus crucial for their detection in natural water systems. Polydopamine (PD)-functionalized surfaces were utilized for the capture of C. parvum oocysts and G. lamblia cysts. Using a semibatch reactor system containing artificial surface water, the average attachment efficiencies of C. parvum oocysts and G. lamblia cysts were 94.1% and 99.7%, respectively, after 96 h. The effect of varying hydrodynamic conditions and surface water chemistries on attachment was also investigated. While the average attachment efficiency of C. parvum oocysts increased from 87.2% to 96.9% with increasing shear force (range: 0.04 Pascal (Pa) to 0.43 Pa), the average attachment efficiency of G. lamblia cysts remained over 99.1% over the range of induced shear forces. Higher attachment efficiencies were observed in streamwater with higher divalent cation concentrations. Antimicrobial properties of the PD surfaces were observed: Escherichia coli, Bacillus subtilis, and Legionella pneumophila attachment to the surfaces resulted in bacterial membrane destruction and consequent detachment. PD surfaces prove to be an attractive candidate for (oo)cyst detection due to their simple and versatile synthesis procedure, relative low cost, and superior capture and retention abilities.