Photograph of the test plates with E. coli colonies (with initial concentration of 107 CFU/ml) exposed to DMA-HEM-4h, HEAA-HEM-4h, DMA-METAC-HEM-4h, HEAA-METAC-HEM-4h microgels and PBS (control) after 24h (A). Relative bacteria colony number for E. coli (with the initial concentration of 106 and 107 CFU/ml, B, and C respectively) incubated with the microgels. The relative colony number was normalized by the number of colonies formed by the bacteria not treated with microgels. * p < 0.05 when compared to the other microgels at the same time point. $ p < 0.05 when compared to the controls (HEAA-HEM-4h and HEAA-METAC-HEM-4h) at the same time point. The data points associated with the controls were not statistically significant over time.