BIOSENSORS AND ELECTROCHEMICAL TRANSDUCTION SYSTEM

1. BIOSENSORS
PRESENTED BY-
NITIN KUMAR

2. BIO-SENSOR
IS A CHEMICAL SENSOR WHICH IS A SELF-CONTAINED DEVICE, CAPABLE
OF PROVIDING REAL TIME ANALYTICAL INFORMATION ABOUT A TEST
SAMPLE IN WHICH RECOGNITION SYSTEM IS BASED ON BIOCHEMICAL OR
BIOLOGICAL MECHANISMS.

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13. ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY
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• TO INVESTIGATE THE RESPONSE OF AN ELECTROCHEMICAL
SYSTEM TO SMALL PERTURBATIONS IN EQUILIBRIUM STATE.
ALSO CHARACTERIZATION OF CHARGE DISTRIBUTION AT
ELECTRODE/SOLUTION INTERFACE AND ELECTRICAL
RESISTANCE OF SOLUTION.
• IMPEDANCE SPECTROSCOPY MEASURED 3 MAIN
PARAMETERS – OHMIC RESISTANCE OF SOLUTION,
CAPACITANCE OF ELECTRODE/ELECTROLYTE INTERFACE AND
RATE CONSTANT OF ELECTROCHEMICAL REACTION.
• EACH FACTOR AFFECTED BY RECOGNITION EVENT
OCCURRING AT ELECTRODE SURFACE.
• ALL FACTORS ARE CALCULATED BY USING NYQUIST PLOT.
Conducting
polymer

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𝑅 𝐶𝑡 =
𝑅𝑇
ℤ𝐹𝐼0
R = gas constant
T = temperature
Z = no. of electrons
F = faraday constant
𝑖0 = exchange current density

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19. 1. PHYSICAL ADSORPTION
• ADSORPTION OF PROTEINS ONTO ELECTRODE
SURFACE VIA – NON-COVALENT INTERACTIONS.
• HYDROGEN BONDING
• ELECTROSTATIC FORCES
• HYDROPHOIC INTERACTIONS
• WEAK VANDER WALL'S FORCES.
• THE PROCESS IS REVERSIBLE, DESORPTION OCCURRED BY INCREASING TEM. & CHANGE IN PH.
• IT TAKES PLACE AT THE LOW TEMPERATURE AND DECREASES WITH INCREASE IN THE TEMPERATURE.
• IT INCREASES WITH THE INCREASE IN SURFACE AREA OF THE ADSORBENT.
• THE MOST POPULAR - SILICA, CELLULOSE ACETATE, ACTIVATED CARBON, AND SYNTHETIC POLYMERS
SUCH AS POLY(VINYL CHLORIDE) (PVC) AND POLYSTYRENE

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