Metabolic diseases are increasing in relevance both in health and the economy in most countries. In this direction, if gold-standard technologies are to be based on blood analysis, non-invasive glucose monitoring is a relevant and great challenge that has not yet been fully resolved. This paper provides an overview of the patent landscape related to wearable biosensors for the monitoring of glucose levels in sweat.
Sweat represents a more suitable medium for the non-invasive sensing and monitoring of glucose than other bodily fluids, such as saliva, tears, or urine. However, the measurement of glucose levels requires the use of highly precise and sensitive sensors, given the low glucose concentration in sweat.
Patents’ data were retrieved from the Espacenet database (www.espacenet.com), provided by the European Patent Office and freely accessible. The search strategy was based on 3 main keywords: “wearable" AND "sweat" AND "glucose”. A set of single sub-keywords allowed for further data retrieval and clustering.
A total of 115 records were collected from Espacenet. After excluding some records that were identified as duplicates or related to applications rather than wearable devices, 95 records were included in the review.
China (63) is the country with the highest number of filings, followed by the USA (28) and Europe (21). The first application was filed in 2006; however, it was not until 2014 that an upward trend in filings became evident, with notable peaks in 2017 and 2021.
A total of 41.5% of the applications are currently pending, while only 35.1% have been granted patents.
The majority of claimed electrochemical sensors are enzymatic sensors.
Graphene represents the most prevalent carbon material utilized in the electrode, followed by rGO and carbon nanotubes. The employment of MXenes and MOF is comparatively limited.
The power supply unit may include a solar cell, a fuel cell, or a lithium-ion battery, but a small-sized lithium battery is preferably used.
This analysis aims to identify promising technologies and related IP for the non-invasive assessment of glucose in wearable systems: continuous monitoring, reliability, and interaction with infusion pumps are just the start.
