Nano-enzyme containers for test elements
Inventors
Baier, Grit • Horn, Carina • Landfester, Katharina • Musyanovych, Anna • Paiphansiri, Umaporn
Assignees
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Publication Number
US-12253517-B2
Publication Date
2025-03-18
Expiration Date
Abstract
The present invention relates to a test element for the detection of an analyte comprising an enzyme, wherein the enzyme is incorporated in a nanocapsule.
Core Innovation
The invention relates to a diagnostic test element for the detection of an analyte using an enzyme. The enzyme is incorporated within the interior of a silica nanocapsule that is substantially impermeable to the enzyme but permeable to an enzyme substrate. In the nanocapsule interior, the hydrophilic polymer is absent in one aspect, or a structuring surfactant is absent in another aspect.
The silica nanocapsule is formed as a polyaddition and/or polycondensation product of monomers formed at the interface in a water-in-oil miniemulsion having a continuous oil phase and a discontinuous aqueous phase dispersed therein. The enzyme is present in the aqueous phase during formation. The nanocapsule is further characterized as a polycondensation product of a tetra-alkoxy silane with a compound RSiX3, where X is halo and R is an optionally substituted C3-C30 alkyl group.
The document links nanocapsule permeability to enzyme size constraints by describing embodiments in which pores have a maximum size smaller than the size of an enzyme, producing a diffusion-limited kinetics behavior and a delayed response associated with shell diffusion. The document also describes inclusion of coenzymes and evaluates enzymatic activity retention and improved stability of encapsulated enzyme in dry layer test strip formats under warm and humid storage conditions.
Claims Coverage
The document provides two independent claims defining a diagnostic test element for analyte detection using an enzyme housed in a silica nanocapsule with selective permeability and specific interior-exclusion and formation conditions. Across the families, the inventive features are organized around (i) enzyme/substrate selective transport, (ii) exclusion of interior components (hydrophilic polymer and/or structuring surfactant), (iii) formation via interfacial polymerization in a water-in-oil miniemulsion, and (iv) defined silica precursor chemistry using tetra-alkoxy silane and RSiX3.
Enzyme housed inside a silica nanocapsule with selective permeability
A diagnostic test element for the detection of an analyte comprising an enzyme and a silica nanocapsule substantially impermeable for the enzyme but permeable for an enzyme substrate, the enzyme being incorporated within the interior of the silica nanocapsule.
Interior free from a hydrophilic polymer
The interior of the silica nanocapsule is free from a hydrophilic polymer.
Interfacial polyaddition and/or polycondensation in a water-in-oil miniemulsion
The silica nanocapsule comprises a polyaddition and/or polycondensation product of monomers formed at the interface in a water-in-oil miniemulsion comprising a continuous oil phase and a discontinuous aqueous phase dispersed therein, the enzyme being present in the aqueous phase.
Tetra-alkoxy silane and RSiX3 polycondensation chemistry
The silica nanocapsule is a polycondensation product of a tetra-alkoxy silane with a compound RSiX3, wherein X is halo and R is an optionally substituted C3-C30 alkyl group.
Interior free from a structuring surfactant
The interior of the silica nanocapsule is free from a structuring surfactant.
Overall, the independent claims define a diagnostic test element in which an enzyme is encapsulated in a silica nanocapsule that blocks enzyme transport while allowing enzyme substrate transport, with the capsule interior lacking specified components (hydrophilic polymer and/or structuring surfactant) and the capsule formed from interfacial polyaddition/polycondensation in a water-in-oil miniemulsion using tetra-alkoxy silane and RSiX3 chemistry.
Stated Advantages
Retained enzymatic activity of encapsulated enzyme in the described test element formats.
Improved stability of encapsulated GDH versus free GDH in dry layer test strips under warm and humid storage conditions.
Diffusion-limited kinetics behavior consistent with shell diffusion and pore-size constraints relative to enzyme size.
Documented Applications
Diagnostic test element and diagnostic test formats for analyte detection using the enzyme and its enzyme substrate, including glucose biosensor test strip/layer formats with enzymatic readout.
Enzyme test strips/layers in dry or lyophilized/freeze-dried formats evaluated under warm/humid storage conditions.
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