Autonomously Sensing Hydrogels for the Rapid and Selective Detection of Pathogenic Bacteria

Abstract

The development of a versatile approach for the rapid and sensitive detection of relevant pathogenic bacteria and autonomous signaling of the detection events in reporter hydrogel film coatings is reported. Exploiting chitosan hydrogel films equipped with chromogenic or fluorogenic reporter moieties, the presence of the Gram-negative bacterium Pseudomonas aeruginosa and the Gram-positive bacterium Staphylococcus aureus is sensed within 1 h by detecting the characteristic enzymes α-glucosidase and elastase with limits of detection (LOD) <45 × 10(-9) M and <20 × 10(-9) M, respectively, for this observation time. The values for the LOD are two to three orders of magnitude smaller than the concentrations of the enzymes detected in the corresponding bacterial supernatants. The results show that the covalently conjugated reporter moieties are exclusively and efficiently reacted by the associated enzyme, allowing in principle for discrimination among different types of bacteria. Since high enzyme concentrations are a result of proliferating bacteria, e.g., in wounds or food, and since the selectivity of the reporting function is easily adapted to bacteria of choice, these reporter hydrogels comprise an interesting platform for the rapid detection of bacteria.

Self-reporting hydrogels rapidly differentiate among enterohemorrhagic Escherichia coli (EHEC) and non-virulent Escherichia coli (K12)

“…Giovanni et al 24 Here we report on the expansion of our previously introduced autonomously sensing hydrogel approach for the simple in situ and selective detection of a potentially life-threatening biosafety level 3 food pathogen. 31,32 To detect the pathogenic E. coli (EHEC) and to differentiate it from non-pathogenic E. coli (K12), the differences in enzyme secretion of these bacteria strains is 12…”

Development of an Intelligent Photosensitive Antibacterial Wound Dressing: Simultaneous Detection and Treatment of Bacterial Infection for Accelerated Wound Healing

“…Numerous studies have been performed to detect the status of a wound through the biochemical or physical markers of the wound healing process. For example, chitosan hydrogel film with a chromogenic or fluorescent reporter moiety have been used to detect Gram‐negative Pseudomonas aeruginosa and Gram‐positive Staphylococcus aureus within 1 hour . A new method has been developed to detect the microbiological state of wound dressings; this dressing responds to the microbial environment of the wound by simple color changes and antibacterial agents.…”

Towards Multiplexed Bacteria Detection by Enzyme Responsive Hydrogels

“…The PDMS mask was prepared according to previous work . The PDMS prepolymer and curing agent (Sylgard ® 184) were mixed in a 10:1 by weight ratio and poured into a polystyrene Petri dish after 30 min degassing.…”

“…In addition, it was shown that this approach can be expanded to application in selective assays, e.g. to differentiate Staphylococcus aureus from Pseudomonas aeruginosa (with clear medical relevance) or to differentiate the S‐1 level E. coli ( K12 ) from the S‐3 level pathogenic E. coli EHEC (with implications for food safety) …”

“…to differentiate Staphylococcus aureus from Pseudomonas aeruginosa (with clear medical relevance) or to differentiate the S-1 level E. coli (K12) from the S-3 level pathogenic E. coli EHEC (with implications for food safety). [18][19][20][21] Here we expand this previously established concept of autonomously sensing hydrogel layers to address the capabilities of multiplexing that is required to afford selectivity (potentially helping to discriminate among several pathogens) and also to reduce false positives by introducing redundancy using different colorimetric substrates. In particular, we aim to implement multiple colorimetric substrates to detect the same (or different) analytes on one single sensor strip.…”