Methods of making a diagnostic composition and compositions therefrom
Inventors
Bhandari, Paridhi • Dendukuri, Dhananjaya • Ganapathy, Vijayakumar • Kandaswamy, Srinivasan • Lewis, Diya
Assignees
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Publication Number
US-8889829-B2
Publication Date
2014-11-18
Expiration Date
Abstract
In one aspect, the invention provides a method for making a hydrophilic-silk composition. The method includes providing at least one strand of silk fiber, treating the silk fiber with an alkaline solution to provide at least one strand of degummed silk fiber, and treating the degummed silk fiber with a treatment solution to provide a hydrophilic-silk composition. The degummed silk fiber or the hydrophilic-silk composition is further immobilized with at least one reagent to make a silk-based diagnostic composition. The invention provides a silk-based diagnostic composition made by the method of the invention, and a diagnostic device that comprises the silk-based diagnostic composition. In another aspect, the invention provides a method of making a diagnostic device. The method includes providing at least one strand of a diagnostic-fiber composition, providing at least one strand of a hydrophobic-fiber composition, inter-weaving the at least one strand of the diagnostic-fiber composition and the at least one strand of the hydrophobic-fiber composition. In one embodiment, the diagnostic-fiber composition and the hydrophobic-fiber composition are both based on silk.
Core Innovation
The invention relates to manufacturing silk-based diagnostic compositions and devices using hydrophilic silk fiber. A strand of silk fiber is treated with an alkaline solution to provide at least one strand of de gummed silk fiber, and the degummed silk is treated with a treatment solution comprising poly(ethylene glycol) based sorbitan derivative, bovine serum albumin (BSA), and 1% PEG 400 to provide a silk-based diagnostic composition precursor.
The invention includes immobilizing at least one reagent onto the at least one strand of degummed silk fiber or onto the hydrophilic-silk composition. The immobilized reagent provides a reagent-immobilized silk-fiber, which is further treated to produce the silk-based diagnostic composition. The disclosed reagents include primary antibodies, secondary antibodies, and antigens, enabling analyte detection using immunoassay formats such as sandwich immunoassay and indirect immunoassay.
The document further describes fabric-based diagnostic devices that use silk fabric structures to support the diagnostic compositions. Sample introduction is aligned with capillary action or wicking through the silk, and an absorption port is described for performing immunoassays. The manufacture is supported by weaving or weaving-based fabrication with patterned silk fabric made from coated silk threads.
Claims Coverage
The independent claims provide two method routes for making silk-based diagnostic compositions. Across the independent claims, three main inventive aspects recur: alkaline de-gumming of silk, treatment with a specified PEG-based sorbitan derivative/BSA/PEG 400 formulation to form hydrophilic silk, and immobilizing at least one reagent onto the treated silk to obtain the diagnostic composition.
Alkaline de-gumming of silk fiber
Treating at least one strand of silk fiber with an alkaline solution to provide at least one strand of de gummed silk fiber.
PEG-based sorbitan derivative/BSA/PEG 400 hydrophilic-silk treatment
Treating the at least one strand of de gummed silk fiber with a treatment solution comprising poly(ethylene glycol) based sorbitan derivative, bovine serum albumin (BSA), and 1% PEG 400 to provide a hydrophilic-silk composition.
Reagent immobilization onto treated silk
Immobilizing at least one reagent onto the at least one strand of degummed silk fiber or onto the hydrophilic-silk composition to provide a reagent-immobilized silk-fiber or a silk-based diagnostic composition.
Preparation sequence for diagnostic composition
Two method routes are covered: treating degummed silk with the specified treatment solution after reagent immobilization, or treating degummed silk to form hydrophilic-silk composition first and then immobilizing at least one reagent.
Together, the independent claims cover methods that convert silk fiber to de gummed silk via an alkaline solution, obtain hydrophilic silk by treatment with poly(ethylene glycol) based sorbitan derivative, BSA, and 1% PEG 400, and immobilize immunoassay reagents, including antibodies and antigens, to form a silk-based diagnostic composition.
Stated Advantages
Hydrophilic silk is enabled for diagnostic use by combining degumming with a BSA/PEG-based sorbitan derivative/PEG 400 treatment.
Reduced nonspecific binding is stated as an outcome of the described treatment approach.
Documented Applications
Fabric-based diagnostic devices using silk fabric structures that support immunoassays with sample introduction by capillary action or wicking and an absorption port.
Immunoassay formats including sandwich immunoassay and indirect immunoassay using immobilized primary antibodies, secondary antibodies, and antigens on silk-based diagnostic compositions.
Weaving-based fabrication to produce fabric-based diagnostic devices using patterned silk fabric formed from coated threads.
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