Ch13: Immunosensors Flashcards
Describe the ELISA procedure and why antibody-to-antibody is needed.
ELISA detects antigens using enzyme-linked antibodies and requires a secondary antibody to enhance specificity and sensitivity
What is aptamer?
Aptamers are synthetic oligonucleotides or peptides that bind specific targets with high affinity, used in biosensors as alternatives to antibodies
Q: What are immunosensors?
A: Biosensors that detect analytes using antibody-antigen interactions.
Q: What is ELISA?
A: Enzyme-linked immunosorbent assay, a technique for detecting and quantifying antigens.
Q: Why is a secondary antibody used in ELISA?
A: To amplify the signal and improve detection sensitivity.
Q: What is the principle of lateral flow assays (LFA)?
A: Detecting analytes using capillary flow through a membrane containing immobilized antibodies.
Q: How does fluorescence improve immunosensing?
A: By enabling highly sensitive and specific detection of targets.
Q: What are aptamers?
A: Synthetic oligonucleotides or peptides that bind specific targets with high affinity, used as antibody alternatives.
Q: How does an ELISA plate’s color relate to antigen concentration?
A: The intensity of the color correlates with the amount of antigen present.
Q: What is the function of interdigitated microelectrodes (IME)?
A: They detect biological targets by measuring impedance changes.
Q: Why is ELONA used in immunosensors?
A: It combines ELISA with oligonucleotide aptamers for enhanced detection.
Q: What is the purpose of washing steps in ELISA?
A: To remove non-specifically bound molecules, improving specificity.
Q: What are monoclonal antibodies?
A: Antibodies from a single B cell line that recognize one specific epitope.
Q: How is colorimetric detection used in LFA?
A: By producing a visible line indicating the presence of the target analyte.
Q: What are polyclonal antibodies?
A: Antibodies from different B cell lines that recognize multiple epitopes of the same antigen.
Q: What is surface plasmon resonance (SPR)?
A: A technique measuring refractive index changes at a sensor surface to detect biomolecular interactions.
Q: How does a smartphone-based immunosensor work?
A: By analyzing images or signals captured by the phone’s camera from a biosensor.
Q: What is an advantage of piezoelectric immunosensors?
A: They can measure mass changes in real time without labeling.
Q: Why are optical fibers used in immunosensors?
A: For efficient light delivery and signal collection in fluorescence-based detection.
Q: How do electrochemical immunosensors work?
A: By measuring electrical changes caused by antibody-antigen interactions.
Q: What are immunosensing kits?
A: Pre-packaged tools for performing rapid and convenient immunoassays.
Q: How does fluorescence ELISA differ from colorimetric ELISA?
A: It uses fluorophores instead of colorimetric substrates, increasing sensitivity.
Q: What is ELISA?
A: A technique using enzymes and antibodies to detect antigens.
Q: How is ELISA quantified?
A: By colorimetric, fluorescent, or electrochemical detection.
Q: What is an aptamer?
A: A synthetic oligonucleotide that binds specific targets.
Q: What is ELONA?
A: ELISA using nucleic acid aptamers instead of antibodies.
Q: How does an LFA differ from ELISA?
A: LFA automates detection using capillary flow without complex washing steps.
Q: How does an IME detect bacteria?
A: By measuring impedance changes when bacteria bind to the electrode.
Q: How does RGB intensity relate to ELISA absorbance?
A: Lower intensity in a specific channel indicates higher absorbance.
