Capacitor-Based Microcantilever Sensor for Analyte Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MEMS sensors experience nonlinearity issues due to changes in properties over time, leading to inaccurate readings, especially when used in systems requiring large movements, and conventional methods like AFM and laser-based techniques are bulky and require external lighting, limiting their compactness and accuracy.
Innovation Solution
An intermittency-based sensor using a microcantilever with a micromechanical beam and electrodes, monitored by a microcontroller, detects frequency changes through capacitance sensing to identify analyte deposition by comparing frequency responses to a calibration curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional laser-based detection methods are used to detect frequency changes of microcantilever, then frequency measurement capability is achieved, but device complexity and size increase due to external lighting requirements, long optical path, and photodetector positioning systems
Solution Approach 1:
The patent replaces the optical detection system (laser, photodetector, optical path) with an electrical capacitance-based sensing system. The capacitance sensor directly measures the position and frequency of the microcantilever beam without requiring external lighting or complex optical alignment, thereby substituting a mechanical/optical system with a simpler electrical sensing system that achieves the same frequency measurement capability.
2Measurement precision
If conventional inertial sensors are used to detect changes in sensor mass and stiffness, then mass and stiffness changes can be measured, but measurement accuracy deteriorates due to nonlinearity in MEMS sensors over time and usage
Solution Approach 1:
The patent utilizes mechanical vibration of the microcantilever beam at its resonant frequency to detect mass and stiffness changes. By exciting the beam and measuring its resonant frequency shifts, the system achieves accurate detection of analyte deposition without suffering from the nonlinearity issues that affect conventional inertial sensors over time. The vibrational approach provides a stable reference that maintains measurement accuracy.
3Adaptability or versatility
If MEMS sensors operate in systems requiring large range of movement, then actuation capability is improved, but nonlinearity increases leading to inaccurate readings
Solution Approach 1:
The patent operates the microcantilever beam in its natural vibrational dynamics regime, using small oscillations around an equilibrium position rather than large static movements. This dynamic operation allows the sensor to maintain linearity and measurement accuracy while still providing sufficient actuation capability for detecting analyte deposition. The system exploits the inherent dynamic behavior of the beam to achieve both adaptability and precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sensor provides accurate and compact detection of analyte presence by utilizing intermittency in frequency domains, enhancing sensitivity and reducing errors through a microcontroller-based alert system.
Implementation Method 1
the plurality of electrodes are configured to connect to a biased source of alternating voltage, wherein the frequency of the alternating voltage is in a frequency range which generates intermittencies in a motion of the free end
Implementation Method 2
Capacitor-based sensor with intermittency sensitivity
Data Source
AI summary
The present disclosure describes an intermittency-based analyte sensor and a method for using the intermittency-based analyte sensor. The intermittency-based analyte sensor includes a microcantilever, a substrate, a plurality of electrodes, a contact pad and a microcontroller. The microcantilever has a micromechanical beam having has a fixed end and a free end. The substrate is connected to the fixed end of the micromechanical beam. The plurality of electrodes are configured to connect to a biased source of alternating voltage. The frequency of the alternating voltage is in a frequency range which generates intermittencies in a motion of the free end. The microcontroller monitors a frequency response of the micromechanical beam; compares the frequency response to a calibration curve, and provides an alert that an analyte has deposited on the surface of the micromechanical beam when the frequency response is less than a calibrated frequency response.