Dissolved core alginate microspheres as “smart-tattoo” glucose sensors

Abstract

The feasibility of multilayer thin film coated dissolved-core alginate-templated microsphere sensors based on fluorescence resonance energy transfer and competitive binding, was explored in simulated interstitial fluid, using glucose as a model analyte. The glucose sensitivity was observed to be 0.89%/mM glucose with a linear response in the range of 0–50mM glucose. The sensor response was observed to be completely reversible in nature with a response time of 120 seconds. The system was further demonstrated to respond similarly using near-infrared dyes (Alexa Fluor-647-labeled dextran as donor and QSY-21-conjugated apo-GOx as acceptor) which exhibited a sensitivity of 0.94%/mM glucose with a linear response in range of 0–50mM glucose, making the sensor more amenable to in vivo use, when implanted in scattering tissue.

Glucose response of dissolved-core alginate microspheres: towards a continuous glucose biosensor

“…The response is observed to be linear up to 6mM glucose concentration, which is the range required to accurately predict glucose concentrations in hypoglycemia. The glucose response sensitivity under dynamic conditions was found to be comparable to the steady state glucose response reported earlier in our previous paper, 60 when compared statistically using a student's paired t-test (a ¼ 0.05). These findings suggest that these dissolved-core alginate microsphere glucose sensors are stable under static and dynamic flow conditions, further supporting their potential for monitoring glucose under physiological conditions.…”

Glicosímetro de pulso

“…Table II presents the accuracy (Arms), the average deviation (B), the standard deviation (SDR) and the precision (Ps) of the measurement pairs collected from all volunteers with the proposed pulse glucometer as a function of the measurements taken with the commercial blood glucose level monitor. Calculations were performed according to the equations (12) to (15). Afterwards the data from the tested glucometer were compared to the data from the commercial glucometer in order to verify the possibility of obtaining a linear curve with an angular coefficient near one unit (identity curve).…”

“…Liu et al [8] proposed a subcutaneous sensor using reverse iontophoresis. Jacobs et al [9] studied otoacoustic emission with blood glucose levels, Lumbroso et al [10] developed a bioimpedance sensor for glucose recognition, whereas Maruo et al [11] have published an article describing a system using near-infrared, Chaudhary et al [12] used dissolved core alginate microspheres as "smarttatto" for glucose measurements, Park et al [13] used a nonenzymatic glucose sensor, Lee and Cui [14] built layer-bylayer self-assembled single-walled carbon nanotubes and Garret et al [15] developed PH-insensitive glucose indicator, among many others. The measuring methods adopted in those studies differ in their proposed instrumentation methods because they do not use optics as a measurement principle, or because they do not use the pulsing characteristic of arterial blood in the described methods.…”