Related Experiment Video
Updated: Jan 21, 2026
10:05
In Vitro Multiparametric Cellular Analysis by Micro Organic Charge-modulated Field-effect Transistor Arrays
Published on: September 20, 2021
2.8K
Molecular-Charge-Contact-Based Ion-Sensitive Field-Effect Transistor Sensor in Microfluidic System for Protein
1Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Sensors (Basel, Switzerland)
|August 7, 2019
Summary
This study presents a novel molecular-charge-contact (MCC) method using an ion-sensitive field-effect transistor (ISFET) for direct protein detection beyond Debye length limits. This biosensor platform enables sensitive antigen-antibody reaction monitoring for in vitro diagnostics.
Area of Science:
- Biotechnology
- Nanotechnology
- Sensor Technology
Background:
- Traditional biosensors face limitations in detecting biomolecules due to the Debye length, restricting sensing range.
- Ion-sensitive field-effect transistors (ISFETs) offer sensitive detection but require specific surface modifications for targeted biomolecule sensing.
Purpose of the Study:
- To demonstrate direct protein sensing beyond the Debye length limit using a molecular-charge-contact (MCC) ISFET.
- To investigate the influence of solution parameters on sensor performance.
- To develop a microfluidic-integrated system for enhanced biosensing capabilities.
Main Methods:
- Utilized a molecular-charge-contact (MCC) based ion-sensitive field-effect transistor (ISFET) sensor.
- Employed biotin-coated magnetic beads immobilized on the ISFET gate insulator via a magnet.
- Integrated a microfluidic device for bound/free molecule separation.
- Investigated streptavidin-biotin interaction as a model for antigen-antibody reactions.
Main Results:
- Achieved direct protein sensing beyond the Debye length limit.
- Observed changes in the ISFET's electrical signal due to pH variations caused by streptavidin binding.
- Demonstrated the importance of microfluidic-based bound/free molecule separation for accurate signal acquisition.
- Evaluated the impact of solution pH and ionic strength on sensor performance.
Conclusions:
- The MCC-based ISFET platform enables direct monitoring of antigen-antibody reactions.
- This approach overcomes the Debye length limitation in protein sensing.
- The integrated microfluidic system enhances the reliability and specificity of the biosensor for in vitro diagnostics.
Related Concept Videos
03:27Ions and Ionic Charges
78.6K
In ordinary chemical reactions, the nucleus — which contains the protons and neutrons of each atom and thus identifies the element — remains unchanged. Electrons, however, can be added to atoms by transfer from other atoms, lost by transfer to other atoms, or shared with other atoms. The transfer and sharing of electrons among atoms govern the chemistry of the elements. During the formation of some compounds, atoms gain or lose electrons to form electrically charged particles called...
78.6K
01:29Field Effect Transistor
1.1K
Field-effect transistors (FETs) are integral to electronic circuits and distinguished by their three-terminal setup: the gate, drain, and source. These transistors operate as unipolar devices, which utilize either electrons or holes as charge carriers, in contrast to bipolar transistors, which use both types of carriers. The primary function of the FET is to modulate the flow of these carriers from the source to the drain through a channel. The voltage difference between the gate and source...
1.1K
02:54Trends in Lattice Energy: Ion Size and Charge
26.5K
An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure of the strength of this attraction. The lattice energy (ΔHlattice) of an ionic compound is defined as the energy required to separate one mole of the solid into its component gaseous ions. For the ionic solid sodium chloride, the lattice energy is the enthalpy change of the process:
26.5K
02:54Ions as Acids and Bases
26.2K
Salts with Acidic Ions
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
26.2K
02:54Lewis Structures of Molecular Compounds and Polyatomic Ions
44.8K
To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:
44.8K
01:19Electric Field of a Continuous Line Charge
2.4K
In physics, symmetry in a system means that something in the considered system remains unchanged due to a specific operation to which it is subjected. For example, consider a horizontal square. The square looks the same if its right and left sides are interchanged. Hence, it is symmetric under a right-left interchange.
In calculations of electric fields, symmetry is of great use. For example, while calculating electric fields of continuous charge distributions.
Consider a line element with a...
In calculations of electric fields, symmetry is of great use. For example, while calculating electric fields of continuous charge distributions.
Consider a line element with a...
2.4K