L1 - Intro to Bio/Chem Sensors

smart sensor

is a device that can detect and respond to physical, chemical, or biological changes in the env. it processes that info to produce an output, like converting changes into measurable signals

what are 3 things a smart sensor does

• collect data from their env. (e.g., temp, pressure, motion)

• process and analyze data

  • using embedded computing or communication capabilities

• transmit the data

  • to other systems or devices for more analysis or action

physical sensor examples

thermometer, pressure sensor, motion sensor, conductivity

chemical sensor examples

pH meter, smoke detector, CO or CO2 meter

biochemical sensor examples

COVID test, pregnancy test, glucose meter

analytical chemistry vs. sensor

• analytical chem

  • measure and detect chemical with analytical methods

  • can be method or small device, like mass spec.

  • can involve sensors, e.g. pH meter for titration

  • pH meter is sensor, titration is analytical

  • sample prep is key

  • discrete or batch measurements

  • analytical methods are not usually specific, e.g. UV-Vis machine can be used to measure diff things

  • specialized equipment

• sensor

  • specific device

  • measurements: usually has rapid or real time response

  • has specificity, specifically measures target compound

  • e.g. for pH meter, acidity; for glucose meter, only glucose

  • minimal expertise required

biosensors: IUPAC definition

A device that uses specific biochemical reactions mediated by isolated enzymes, immunosystems, tissues, organelles or whole cells to detect chemical compounds usually by electrical, thermal or optical signals.

what’s a transducer

physiochemical or transducer microsystem

convert energy to an analytic signal or smtg. that can be measured

e.g. electrical: ion generation, resistance, potential —> conductrometric, amperometric, potentiometric, FET

bio/chem sensors: key features

• selectivity and specificity

• sensitivity

• rapid response time

• user-friendly operation

• minimal or no sample prep

• portability and miniaturization: compact and portable design

• integration with systems: integrate w/ devices for data collection, processing

• stability: long-term reliability, consistent performance under env conditions

• reproducibility

• cost-effectiveness

selectivity and specificity

• designed to detect specific chemical substances or biological mlcls

• accurately identify them even in complex env or matrix

sensitivity

High sensitivity to detect even trace amounts of target analytes, critical for applications like medical diagnostics.

reproducibility

delivers consistent, repeatable results across multiple measurements

ideal biosensor characteristics

• fast analysis time, real-time responses to target analytes

• sensitivity, for detection of low concentrations of analytes

  • low false negatives

• specificity, for discrimination btwn target analytes, and closely related species

  • less false positive analyses

• highly reproducible, easy to calibrate

• highly accurate, less false-positives and false-negatives

• robustness, insensitive to env. conditions (temp, electronic interferences)

• low unit and operational costs, can be implemented more widely

• size and weight, miniature is preferred and portable

• multianalyte, if it can detect multiple simultaneously, it’s preferred and desired for efficient cost, time, size

• fully automated systems are desired

how do sensors work, from sample to detector

sample → analyte → bioreceptor or chemical receptor → transducer → (signal) → detector

sensors, types of measurements

• quantitative measurements

• semiquantitative

• positive/negative

• research (e.g. investigate mlclr interactions)

Selectivity

• extent to which analytes can be measured simultaneously by sensors without interferences

• multiple analytes can be detected independently

• multi-component analysis

Specificity

• single component analysis

• individual component in real sample can be undisturbedly measured by specific reagent, sensor or measuring system

selective vs specific

• selective if it can detect several components simultaneously but independent of e/o

• specific if only one species can be detected independently from other components

  • no signal from other components