A non-enzymatic glucose sensor enabled by bioelectronic pH control

Abstract

Continuous glucose monitoring from sweat and tears can improve the quality of life of diabetic patients and provide data for more accurate diagnosis and treatment. Current continuous glucose sensors use enzymes with a one-to-two week lifespan, which forces periodic replacement. Metal oxide sensors are an alternative to enzymatic sensors with a longer lifetime. However, metal oxide sensors do not operate in sweat and tears because they function at high pH (pH > 10), and sweat and tears are neutral (pH = 7). Here, we introduce a non-enzymatic metal oxide glucose sensor that functions in neutral fluids by electronically inducing a reversible and localized pH change. We demonstrate glucose monitoring at physiologically relevant levels in neutral fluids mimicking sweat, and wireless communication with a personal computer via an integrated circuit board.

Flexible potentiometric pH sensors for wearable systems

“…83 Tears can reveal information regarding systemic disorders, including diabetes and ocular conditions (Table 1). [84][85][86] For instance, a decrease in tear pH may suggest a corneal infection before symptoms are visible. 87 However, among the many ionic species found in tears, pH is least oen measured due to the low concentrations of H 3 O + present.…”

Soft and Ion‐Conducting Materials in Bioelectronics: From Conducting Polymers to Hydrogels

“…The FET channel is made of an H + conducting hydrogel, maleic‐chitosan (poly (β‐(1,4)‐ N ‐Maleoyl‐D‐glucosamine)), which is a polysaccharide chitin derivative with high proton conductivity . Protonic bioelectronic devices can modulate pH in electrolytes and monitor metabolic reactions, control bioluminescence with pH, and interface with ion channels . In Figure 3b, an ion channel integrated with a Pd/PdH x contact was used to regulate protons flow across a supported lipid layer (SLB) .…”

Radio-Frequency Biosensors for Real-Time and Continuous Glucose Detection

“…For the systematic administration of a patient’s glucose, continuous glucose monitoring (CGM) using minimally invasive sources such as sweat or tears is less demanding. CGM improves healthcare by providing a higher data collection rate with increased reliability while avoiding the discomfort of the prick test [ 7 , 8 ]. From this point of view, a real-time and continuous radio-frequency (RF) glucose biosensor with the great advantages of being noninvasive and noncontact and monitoring a nonionized RF spectrum can be a new alternative.…”