Pathogen-Imprinted Organosiloxane Polymers as Selective Biosensors for the Detection of Targeted E. coli

Abstract

Early detection of pathogens requires methods that are fast, selective, sensitive and affordable. We report the development of a biosensor with high sensitivity and selectivity based on the low-cost preparation of organosiloxane (OSX) polymers imprinted with E. coli-GFP (green fluorescent protein). OSX polymers with high optical transparency, no cracking, and no shrinkage were prepared by varying several parameters of the sol-gel reaction. The unique shape and chemical fingerprint of the targeted inactivated E. coli-GFP were imprinted into bulk polymers by replication imprinting where the polymer solution was dropcast onto a bacteria template that produced a replica of the bacterial shape and chemistry on the polymer surface upon removal of the template. Capture performances were studied under non-laminar flow conditions with samples containing inactivated E. coli-GFP and compared to inactivated S. typhimurium-GFP. Capture selectivity ratios are dependent on the type of alkoxysilanes used, the H 2 O:silane molar ratio, and the polymerization temperature. The bacteria concentration in suspension ranged from~6 × 10 5 to 1.6 × 10 9 cells/mL. E. coli-imprinted OSX polymers with polyethylene glycol (PEG) differentiated between the targeted bacterium E. coli, and non-targeted bacteria S. typhimurium and native E. coli-GFP, achieving selectivity ratios up to 4.5 times higher than polydimethylsiloxane (PDMS) and OSX polymers without PEG.

Molecularly Imprinted Polymers for Cell Recognition

“…But, due to the synthetic limitations of PDMS, authors moved to organosiloxane polymers made by sol-gel chemistry. The broad selection of available silanes allowed to benefit from a plethora of functionalities whilst retaining optical transparency and mechanical resistance [21]. Although the mechanical stability of inorganic materials is usually higher than their organic counterparts, it is important to consider the mechanical stress which the cells undergo during the stamping procedure, might be damaging more delicate targets, such as human cells.…”

Fighting Antibiotic‐Resistant Bacteria: Promising Strategies Orchestrated by Molecularly Imprinted Polymers

“…Nowadays, the most frequently used strategies for surface imprinting of bacteria is the microcontact stamping method in a prepolymerized crosslinking polymeric network such as polyurethanes, polymethylsiloxanes (PDMS) or polyacrylates [33b,c, 66–68] . Typically, the bacteria suspension is drop‐casted on a glass slide and allowed to dry so that randomly attached cells are left on the glass slide (Figure 4).…”

Bacterial Sensing and Biofilm Monitoring for Infection Diagnostics

“…Over the last two decades, much effort has been expended towards the successful implementation of cell imprinting using stamping, cell lithography, microcontact printing, and electropolymerization. [ 135,138,139 ] Electrochemical methods that use electropolymerization of a thin film of the recognition element directly on the electrode surface are particularly useful for designing functional recognition sites. [ 135 ] This approach provides precise control of the thickness of the recognition layer while avoiding extensive synthesis and purification procedures.…”