Introduction$ of biosensors - biomed lec 8

Introduction of Biosensors

Overview of the Lecture

  • Introduction by Dr. Guocheng Fang, Research Fellow at the School of Biomedical Engineering.

  • Leader of the "Intelligent Organoid-on-Chip (IOC)" group.

  • Focus area includes the integration of mini organs in laboratory settings with electronic and photonic sensing.

Background of Sensors

Definition of a Sensor

  • A sensor is a device used to detect and respond to input (stimulus) from its physical environment.

    • **Input Types: **

    • Physical quantities like pressure, force, strain, light, etc.

    • Converts these inputs into useful signals (either analog or digital).

    • Functionality: Can detect or quantify a variety of conditions.

Examples of Sensors

  • In the Body:

    • Light sensors

    • Sound sensors (acoustic signals)

    • Chemical sensors

    • Temperature sensors

    • Pressure sensors

  • Wearable Sensors:

    • Electrical heart sensor, blood oxygen sensor, etc.

    • Sensors in smartwatches, clothing, etc.

  • In Automobiles:

    • Various sensors include:

    • Differential sensors

    • Steering-torque sensors

    • Throttle position sensors

    • Fuel level sensors

    • Non-contacting angle sensors

    • LIDAR, Radar, Cameras, GPS, and Wheel Encoders.

Types of Stimuli Measured by Sensors

  • Acoustic:

    • Acoustic Wave parameters (amplitude, phase, spectrum).

  • Biological & Chemical:

    • Concentration measurements (gases or liquids).

  • Electrical:

    • Current, voltage, electric field measurements.

  • Magnetic:

    • Magnetic field metrics (flux, amplitude).

  • Optical:

    • Measurements involving refractive index, reflectivity, and absorption.

  • Thermal:

    • Temperature, heat flux, specific heat.

  • Mechanical:

    • Measurements on position, velocity, acceleration, force, strain, torque, pressure.

Types of Sensors

  • Thermal Sensors:

    • Important for applications needing temperature monitoring.

    • Indirectly measures temperature by assessing other physical properties (pressure, volume).

  • Acoustic Sensors:

    • Used in SONAR and RADAR for position measurement and environment mapping.

  • Electrical Sensors:

    • Detects electrical parameters and are essential in control mechanisms for power electronics.

  • Magnetic Sensors:

    • Utilized in power steering, security, and transmission line measurements.

  • Chemical Sensors:

    • Detect specific substances and convert their concentrations into electrical signals.

  • Mechanical Sensors:

    • Translate physical pressure or force into quantifiable output signals.

  • Optical Sensors:

    • Detect electromagnetic radiation across a wide optical range; often utilize the photoelectric effect.

Introduction to Biosensors

Definition of a Biosensor

  • A biosensor is an analytical device that:

    • Utilizes a biological recognition element for detecting a target analyte.

    • Converts the recognition event into a measurable signal.

Applications and Advantages

  • Point-of-Care (POC) Devices:

    • These devices provide rapid diagnostics using minimal samples.

    • Improve healthcare flows and have user-friendly interfaces.

    • Offer high sensitivity, reliability, and lower costs.

Historical Developments in Biosensors

  • Timeline of Innovations:

    • 1962: First glucose biosensor.

    • 1975: First immunosensor.

    • 1980s: Optical biosensors emerge.

    • 2010s: Introduction of advanced wearable and nanotechnology biosensors.

Market Potential for Biosensors

  • The biosensors market is predicted to reach:

    • Value: USD 36.7 billion by 2026.

    • Growth Rate: 7.5% compounded annual growth rate (CAGR) from 2021 to 2026.

Core Components of a Biosensor

  • Recognition Element:

    • Biological materials such as enzymes, antibodies, or nucleic acids that bind to the analyte.

  • Transducer:

    • Converts the biochemical event into a measurable signal, involving various forms such as optical, electrochemical, or mechanical.

Key Parameters of Biosensor Performance

  1. Linearity: High linearity is essential for accurate measurement in high concentrations.

  2. Sensitivity: Ability to discriminate between small differences in analyte concentrations.

  3. Selectivity: The preference of the sensor for its target analyte over potential interferents.

  4. Response Time: The time required to achieve a significant response.

  5. Reproducibility: Consistent performance across multiple tests.

Example of a Biosensor in Research

  • Application in Drug Screening for Heart Failure:

    • Utilized cardiac organoids to test candidate drugs (Group A and Group B).

    • Implemented microfluidic generation for real-time data acquisition on cardiac contraction responses.

Future Directions in Biosensor Technology

  • Increase in the integration of AI and machine learning in the analysis and operational efficiency of biosensor devices, enhancing diagnostics, treatment, and monitoring protocols.