Nano-Plasmonic Biosensing Signal Chain for Low-Noise Detection
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Solution Overview
Problem
Conventional nano-plasmonic biosensing systems face challenges due to noise in signal amplification and unstable light sources, affecting measurement accuracy and sensitivity.
Innovation Solution
An optical nano-biosensing system incorporating a nano-plasmonic sensing device with a light-source control circuit, high-resolution analog-to-digital converter, and intelligent electronic device, which includes a signal-amplifying circuit, root-mean-square processor, and absolute-mean processor to enhance signal processing and noise reduction, and uses multiple total internal reflections for improved sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional current amplifier is used to amplify nano-plasmonic resonance signal, then signal amplification is achieved, but measurement precision deteriorates due to noise introduction
Solution Approach 1:
The patent replaces the conventional current amplifier with a transimpedance amplifier that directly converts photocurrent from the photodetector to voltage signal. This substitution eliminates the need for separate transimpedance conversion stage and reduces noise introduction while maintaining signal amplification capability. The transimpedance amplifier integrates both current-to-voltage conversion and signal amplification in a single low-noise device, thereby improving measurement precision.
Solution Approach 2:
The patent introduces a low-pass filter as an intermediary component between the transimpedance amplifier and the data acquisition system. This filter acts as a noise barrier that selectively passes the desired signal frequency range while attenuating high-frequency noise components. By placing this intermediary filter in the signal path, the system achieves effective noise reduction without compromising the integrity of the measured nano-plasmonic resonance signal.
2Device complexity
If conventional light source is used without control circuit, then system complexity is reduced, but reliability deteriorates due to unstable incident light
Solution Approach 1:
The patent implements a feedback control circuit that continuously monitors the output intensity of the light source and adjusts the driving current accordingly to maintain stable output. The feedback mechanism compares the actual light intensity with a reference value and dynamically compensates for fluctuations by adjusting the light source driving current. This feedback loop ensures reliable and stable incident light intensity throughout the measurement process, eliminating the need for complex mechanical stabilization mechanisms.
3Measurement precision
If signal amplification is performed without noise reduction, then sensitivity is improved, but measurement precision deteriorates due to accumulated noise
Solution Approach 1:
The patent performs noise reduction through low-pass filtering before the signal undergoes full amplification and digital processing. By applying the low-pass filter early in the signal chain, noise components are attenuated before they can be amplified along with the signal. This preliminary noise reduction action prevents noise accumulation throughout subsequent processing stages, thereby maintaining high detection sensitivity with improved signal-to-noise ratio.
Solution Approach 2:
The patent utilizes the frequency characteristics of the nano-plasmonic resonance signal to convert noise into a beneficial filtering mechanism. By designing the transimpedance amplifier and low-pass filter with cutoff frequencies matched to the resonance signal frequency, the system allows the desired signal to pass through while automatically attenuating out-of-band noise. The frequency-selective amplification transforms what would be harmful broadband noise into a beneficial narrowband signal enhancement, improving measurement 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 system provides enhanced sensitivity and accuracy in detecting analyte molecules by stabilizing light sources and effectively reducing noise, allowing for precise molecular binding kinetic curve analysis.
Implementation Method 1
The incident light is frequency modulated at a specific modulation rate
Implementation Method 2
The light detector detects an emergent light from the sample receiver to generate a detection signal
Implementation Method 3
The signal-amplifying circuit is connected to the light detector and converts a specific modulation frequency range of the detection signal to generate an amplified signal
Implementation Method 4
The high-resolution analog-to-digital converter is connected to the signal-amplifying circuit and digitizes the amplified signal to generate a digital signal
Implementation Method 5
As the recognition molecules on the noble metal nanoparticles bind with the analyte, the local refractive index at the surface of the noble metal nanoparticles changes, and hence the optical properties of the noble metal nanoparticles such as absorption and scattering cross-sections change correspondingly
Data Source
AI summary
An optical nano-biosensing system and a method thereof are provided. The optical nano-biosensing system includes a nano-plasmonic sensing device, a high-resolution analog-to-digital converter, a signal acquisition and processing device, and an intelligent electronic device. The nano-plasmonic sensing device further includes a light-source control circuit, a sample receiver, a light detector, and a signal-amplifying circuit. The sample receiver receives a sample. The light-source control circuit generates an incident light from a light source to be projected onto the sample receiver. The light detector detects an emergent light from the sample receiver to generate a detection signal. The signal-amplifying circuit converts the detection signal to generate an amplified signal. The high-resolution analog-to-digital converter digitizes the amplified signal to generate a digital signal. The signal calculator of the signal acquisition and processing device operates the digital signal to generate calculated information.