Dual Enzyme‐Responsive Capsules of Hyaluronic Acid‐block‐Poly(Lactic Acid) for Sensing Bacterial Enzymes

Abstract

The synthesis of novel amphiphilic hyaluronic acid (HYA) and poly(lactic acid) (PLA) block copolymers is reported as the key element of a strategy to detect the presence of pathogenic bacterial enzymes. In addition to the formation of defined HYA-block-PLA assemblies, the encapsulation of fluorescent reporter dyes and the selective enzymatic degradation of the capsules by hyaluronidase and proteinase K are studied. The synthesis of the dual enzyme-responsive HYA-b-PLA is carried out by copper-catalyzed Huisgen 1,3-dipolar cycloaddition. The resulting copolymers are assembled in water to form vesicular structures, which are characterized by scanning electron microscopy, transmission electron microscopy, dynamic light scattering (DLS), and fluorescence lifetime imaging microscopy (FLIM). DLS measurements show that both enzymes cause a rapid decrease in the hydrodynamic diameter of the nanocapsules. Fluorescence spectroscopy data confirm the liberation of encapsulated dye, which indicates the disintegration of the capsules and validates the concept of enzymatically triggered payload release. Finally, cytotoxicity assays confirm that the HYA-b-PLA nanocapsules are biocompatible with primary human dermal microvascular endothelial cells.

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

“…15,16,17,18 In different strategies, virulence factors secreted by pathogenic bacteria are targeted for the in situ detection. 19,20,21,22 Zakir Hossain et al 23 reported for instance on a lab-onpaper assay for the rapid and sensitive detection of E. coli in water. In this method the reporter 5 elements were printed on a small paper strip.…”

Enzymatically triggered rupture of polymersomes

“…1, 2 Due to their mechanical stability, 1, 3, 4 capacity for additional functionalization, and lower permeability, 5 polymersomes offer significant advantages over other bilayer vesicle in encapsulating and transporting enzymes, 6, 7 proteins, 8, 9 drugs, 9–14 and biomedical imaging and diagnostics. 15–18 Furthermore, the interior compartment of polymersomes has been engineered to serve as a micro-environment for protein expression, 8 gene expression, 19 and enzymatic reaction. 6, 7, 20–23 Blending each of these functions into different compartments within polymersomes could potentially lead to the development of protocells that mimic the metabolism, 6 enzymatic activity, 6, 7, 20–22, 24 and communications of real cells.…”

“…Somatologically favorable enzymatic reactions also have been used to control the release of encapsulants from polymersomes. 14, 17, 18, 23 Although these strategies have successfully shown the disruption of polymersomes to trigger the release of encapsulants, few studies have demonstrated the ability to tailor the rate of rupture/release using an enzyme cascade which can be readily controlled by the concentration of substrate.…”

“…Previous studies also have reported the rupture of polymersomes resulting from the interaction between membrane-associated substrate and free enzyme. 17, 18 Furthermore, membrane-associated photosystem II (PSII) enzyme shows high rates of enzymatic reaction. 45 This enzymatic reaction was ascribed to a membrane-associated heme catalase in PSII.…”

Autoinducer Sensing Microarrays by Reporter Bacteria Encapsulated in Hybrid Supramolecular‐Polysaccharide Hydrogels

“…Among the various new formats for rapid, sensitive and selective bacteria detection, vesicle based approaches, autonomously reporting hydrogel films, as well as hydrogel dot microarrays have garnered particular attention. These formats mainly rely on the detection and reporting of secreted bacterial enzymes, DNA, and virulence factors . For many infections, such as wound infections, bacteria reside in a so‐called biofilm, which represents a confluent community of bacteria protected by an extracellular polymeric matrix .…”