Ch12: Glucose Sensors Flashcards
What is continuous glucose monitoring (CGM)?
CGM uses subcutaneous sensors to measure glucose levels in interstitial fluid every 1–5 minutes, often wirelessly
Why are commercial glucose meter readings higher than actual glucose concentrations?
They report “plasma equivalent” concentrations, which are higher than whole blood glucose levels
What are glucose sensors?
Devices that detect glucose concentration in a sample, often using enzymatic or non-enzymatic methods.
What is the most common enzyme used in glucose sensors?
Glucose oxidase (GOx).
Q: What is continuous glucose monitoring (CGM)?
A: A technology that provides real-time glucose level measurements through a subcutaneous sensor.
Q: How does a CGM sensor communicate data?
A: Via wireless transmission to an external device or smartphone.
Q: What is an electrochemical glucose sensor?
A: A sensor that measures glucose concentration by detecting electrical signals from enzymatic reactions.
Q: How does GOx catalyze glucose oxidation?
A: By converting glucose to gluconolactone and hydrogen peroxide.
Q: What is the principle of optical glucose sensors?
A: Measuring glucose levels based on changes in light absorbance or fluorescence.
Q: What is the role of a co-factor in glucose sensors?
A: It assists enzymes in the oxidation process, e.g., FAD in glucose oxidase.
Q: Why are enzymatic glucose sensors popular?
A: They are highly specific and sensitive to glucose.
Q: What is the difference between amperometric and colorimetric glucose detection?
A: Amperometric measures electrical current; colorimetric measures color change.
Q: Why is GDH-PQQ used in some glucose sensors?
A: It allows oxygen-independent glucose measurement, improving accuracy.
Q: How do paper-based glucose sensors work?
A: By embedding reagents on paper to produce color changes or signals in response to glucose.
Q: What are the drawbacks of optical glucose sensors?
A: They can be affected by sample turbidity and require complex setups.
Q: What are the two major advantages of GDH-PQQ over GOx?
A: Oxygen independence and higher stability.
Q: How do glucose meters display higher-than-actual readings?
A: By reporting plasma-equivalent glucose concentrations.
Q: What is the detection mechanism of GOx and ferricyanide?
A: Electrochemical detection via ferricyanide reduction.
Q: Why is miniaturization important for glucose sensors?
A: It enables portable, point-of-care testing and integration with wearable devices.
Q: What is an advantage of using LEDs in glucose detection?
A: LEDs are energy-efficient and provide stable light for optical sensors.
Q: How is glucose measured in a spectrophotometer?
A: By detecting changes in absorbance or fluorescence due to enzymatic reactions.
Q: What is a glucose assay kit?
A: A tool containing reagents for quantitative glucose measurement, often using spectrophotometry.
Q: What is continuous glucose monitoring (CGM)?
A: Real-time glucose measurement using subcutaneous sensors.
Q: Why do glucose meters overestimate concentrations?
A: They display plasma-equivalent concentrations higher than whole blood glucose.
Q: What are the chemical components in GOx and benzidine detection?
A: Enzyme: glucose oxidase (GOx), Mediator: benzidine, Mechanism: colorimetric.
Q: What are GDH and PQQ benefits?
A: Oxygen independence and higher stability.
Q: Write the formula for GDH and NAD+.
A: Glucose+NAD^+→Gluconate+NADH
