Biosensors with hydrophilic polyurethane membranes

Inventors

McCanless, Jonathan D. • Ouyang, Tianmei • Oja, Stephen M. • Ojha, Yagya Raj • OZEL, Rifat Emrah • Fox, Cade B. • Liu, Zenghe • Feldman, Benjamin J.

Assignees

Abbott Diabetes Care Inc

Abstract

The present disclosure provides an analyte sensor comprising a working electrode, a sensing layer disposed on at least a portion of the working electrode, and a hydrophilic polyurethane membrane overcoating at least the sensing layer, wherein the hydrophilic polyurethane is aliphatic, aromatic, or both aliphatic and aromatic. The hydrophilic polyurethane membrane limits the transport of mass to the sensing layer without the need to be crosslinked. With such membrane, the analyte sensor can provide consistent analyte measurements over a temperature range of about 22-42° C. The present disclosure is further related to a method of forming an analyte sensor comprising providing a working electrode, disposing a sensing layer on at least a portion of the working electrode, and coating at least the sensing layer with a hydrophilic polyurethane membrane, wherein the hydrophilic polyurethane is aliphatic, aromatic, or both aliphatic and aromatic.

Core Innovation

The invention is a creatinine sensor that includes a working electrode and a creatinine sensing layer disposed on at least a portion of the working electrode. The sensing layer is overcoated by a hydrophilic polyurethane membrane that covers at least the sensing layer and serves as a mass-transport limiting membrane. The hydrophilic polyurethane membrane is aliphatic, aromatic, or both aliphatic and aromatic.

The hydrophilic polyurethane membrane is defined as a single copolymer comprising a polyurethane and a second polymer, where the second polymer is a hydrophilic polymer. The membrane is described as non-crosslinked and is contrasted with conventional crosslinked poly(4-vinylpyridine) membranes used for temperature-dependent signal correction. The membrane chemistry is further described with mechanical and water-uptake characteristics.

The sensor is configured to be partially inserted into a user's skin such that a distal portion of the sensor is in contact with interstitial fluid to detect creatinine in vivo. In described embodiments, the sensing layer includes one or more enzymes for detecting creatinine and a redox mediator, and detection is based on applying a potential to the working electrode and correlating a signal proportional to creatinine concentration.

Claims Coverage

The independent claim coverage centers on a creatinine sensor architecture and membrane composition, with a skin-insertion configuration for in vivo interstitial-fluid detection. The claim set includes two core inventive features, with dependent refinements that specify membrane composition, non-crosslinked character, membrane properties, and sensing components.

Overall, claim coverage focuses on the combination of a hydrophilic aliphatic and/or aromatic polyurethane membrane defined as a single copolymer of polyurethane and a hydrophilic second polymer that overcoats the creatinine sensing layer, and partial insertion into a user's skin so the distal portion contacts interstitial fluid for in vivo creatinine detection. Dependent claims further refine membrane material properties, sensing-layer composition, and signal generation and correlation using an applied potential.

Stated Advantages

Documented Applications