Smart hydrogel based microsensing platform for continuous glucose monitoring

Abstract

In this paper, we present preliminary results showing the response of glucose-sensitive hydrogels, confined in micro-pressure sensors, to the changes in environmental glucose concentration. The glucose concentrations were incrementally varied between 20 and 0mM in 0.15M PBS solution at 7.4 pH and bovine serum at 7.4 pH at room temperature and response of the sensor was recorded. The micro sensors demonstrate a response time of 10 minutes in both PBS and serum. Tissue response after 55 days of subcutaneous implantation of a EtO sterilized sensor in mice is presented. The preliminary analysis of the surrounding tissue shows inflammation which is believed not to interfere with the sensor performance.

Thermodynamic analysis of the selectivity enhancement obtained by using smart hydrogels that are zwitterionic when detecting glucose with boronic acid moieties

“…The average magnitude of the decrease is 9.1 kPa ± 0.05 kPa. The response time in the macrosensor is quite large, but we have already demonstrated elsewhere a response time of order ten minutes using the same GSH in a microchip glucose sensor [47]. In Figure 4, the measured value of Π tot increases in response to the increase in fructose concentration from zero to 5 mM.…”

B1.2 - Hydrogel-Based Biochemical Sensors

“…Binding of glucose is characterized by a dissociation constant of the glucose molecule to PBA, K G = 9.1 mM. The fraction α of the ionized PBA groups depends on local pH value and on the glucose concentration c α in the gel according to [3,4]…”

“…In recent years, numerous attempts have been made to develop a miniature, enzyme-free wireless implantable glucose sensor. Such a device, when implanted in subcutaneous tissue, will continuously measure glucose level, which can be interrogated at will by the patient and also recorded automatically [1][2][3][4][5][6]. Real-time glucose monitoring can provide maximal information about changing blood glucose levels throughout day and night, including the direction, magnitude, duration, and frequency of such fluctuations.…”

Piezoresistive Chemical Sensors Based on Functionalized Hydrogels

“…In [1], the sensitivity of a capacitive glucose sensor with an acrylamide/methacrylamidophenylboronic acid/N,N-methylenebisacrylamide (AAm/MAAmPBA/BIS) hydrogel confined in the 2.8 × 2.8 × 0.2 mm 3 cavity was achieved to be 0.15 kPa/mM over the glucose concentration range 0-20 mm in the linear region of the sensor characteristic. In [43], the piezoresistive glucose sensor with an acrylamide/ 3-acrylamidophenylboronic acid/N-3-dimethyl-aminopropyl acrylamide/N,N-methylenebisacrylamide (AAm/3-AAmPBA/DMAPAAm/BIS) hydrogel in the chip cavity of 1 × 1 × 0.4 mm 3 displayed a sensitivity of 0.005 kPa/mM over the range 0-20 mM glucose. 3.1.…”