Given the enormous burden pathogens pose on human health, rapid capture and removal of bacteria for sterilization or further bacterial detection is essential. Herein, tannic acid-functionalized virus-like Fe3O4 (vFe3O4-TA) was established for bacterial enrichment. We investigated the ability of vFe3O4-TA to capture Gram-negative bacteria (E. coli, S. flex and S. typhi) and Gram-positive bacteria (S. aureus, MRSA and LM), respectively. Compared to the capture efficiency of <15 % for Gram-negative bacteria, vFe3O4-TA showed excellent selectivity and efficiency in isolating Gram-positive bacteria with >87 % removal efficiency. GFN-xTB semiempirical quantum chemical calculations revealed that the selective recognition originates from the high affinity between TA and peptidoglycan. Without impacting ingredients, the TA-mediated trapper also shows excellent ability to distinguish Gram-positive bacteria in juice samples. These results are expected to reveal the interaction of TA with bacteria, and inaugurate a potential natural safe tool for food safety control, medical treatment and environmental remediation.
Keywords: Adsorption; Gram-positive bacteria; Independent gradient model; Magnetic separation; Tannic acid.
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