Head-oriented adsorption of bacteriophages on paper-based device for fluorescent analysis of Klebsiella pneumoniae

Abstract

Klebsiella pneumoniae (K. pneumoniae), an opportunistic pathogen, causes a noticeable global public health concern because of the spread of mobile pools carrying virulence and antibiotic resistance genes. Timely and accurate diagnosis of this pathogen is crucial for effectively controlling its extensive dissemination. Herein, a paper-based device (PBD) with 96 micro reaction zones compatible with a microplate reader was constructed through the electrostatic interaction between head of bacteriophage and poly dimethyl diallyl ammonium chloride (PDDA). The PBD was fabricated by adopting a cost-effective wax printing technology to create hydrophobic barriers on a filter paper with a custom stamp. The modification of PDDA in the micro reaction zones endued positively charged interface, allowing the negatively-charged bacteriophage heads to adhere in the micro reaction zones while exposing the positively-charged tails. The exposure of bacteriophage tails facilitated efficient and specific capture of the target pathogen. By employing fluorescein isothiocyanate-labeled K. pneumoniae biopanning peptides as signal tracers, a fluorescent method for analyzing K. pneumoniae was established on the PBD with a dynamic range of 5.0 × 10² to 1.0 × 10⁸ CFU/mL. The potential application of the PBD fabricated by head-oriented adsorption of bacteriophages was validated through the analysis of K. pneumoniae in various real samples with satisfying results.