NCD Optical Sensor for Evanescent Wave Spectroscopy
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Solution Overview
Problem
Current sensor technologies for chemical and biological analysis are limited by poor sensitivity, unspecific analyte binding, and the need for fluorescent labels, which can interfere with molecular interactions, and lack biocompatibility and mechanical stability, making them unsuitable for repeated use and harsh environments.
Innovation Solution
An optical sensor unit for infrared evanescence wave spectroscopy using a waveguide with a nano-crystalline diamond (NCD) sensor surface, which provides high selectivity, sensitivity, and throughput, and can be functionalized for specific binding of chemical and biological substances, allowing for in situ analysis in harsh conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current transducer materials (polystyrene beads, carbon electrodes, gold, silicon, oxidized silicon, glass) are used, then device fabrication is relatively straightforward, but they fail to provide sufficient smoothness, homogeneity, chemical stability, and biocompatibility for sensitive biochemical sensing
Solution Approach 1:
The patent employs diamond, a composite material with unique properties combining extreme chemical inertness, mechanical hardness, optical transparency, and biocompatibility. Diamond serves as both the sensor surface and waveguide material, providing the required chemical stability and smoothness while being amenable to fabrication through chemical vapor deposition (CVD) techniques.
Solution Approach 2:
The patent changes the material parameter from conventional sensor materials to diamond, which fundamentally alters the chemical stability, surface smoothness, and biocompatibility parameters. This material substitution enables operation in harsh environments and repeated usage without degradation.
2Measurement precision
If fluorescent labeling techniques are used for molecular detection, then specific molecules can be detected, but the fluorescent labels interfere with molecular binding and require tedious sample preparation
Solution Approach 1:
The patent extracts the detection function from fluorescent labeling and transfers it to the diamond sensor surface itself. The diamond surface with its evanescent field serves as the detection platform, eliminating the need for fluorescent labels and their associated sample preparation complexity while maintaining detection specificity.
Solution Approach 2:
The diamond sensor surface acts as an intermediary between the analyte and the detection system. It provides a biocompatible interface that enables direct molecular binding without fluorescent labels, using evanescent wave spectroscopy to detect binding events through changes in the optical properties of the diamond surface.
3Duration of action of stationary object
If conventional sensor surfaces are used, then device fabrication is simpler, but they lack the mechanical stability and chemical inertness required for repeated use in harsh environmental conditions
Solution Approach 1:
Diamond's exceptional mechanical properties (hardness, elastic modulus) and chemical inertness provide the required durability for repeated use in harsh conditions including extreme pH, temperature, and pressure. The material can be fabricated using CVD techniques, making it suitable for production despite the advanced manufacturing process.
4Reliability
If diamond is used as the sensor material, then chemical stability, smoothness, and biocompatibility are greatly improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent changes the material parameter to diamond, which fundamentally improves biocompatibility, chemical stability, and surface smoothness. The fabrication complexity is managed through established CVD techniques that can produce diamond films with controlled properties suitable for sensor applications.
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 NCD-based sensor unit enables sensitive and selective analysis of chemical and biological substances, providing reproducible results and biocompatibility, suitable for repeated use and operation in a wide range of environmental conditions, with enhanced sensitivity and specificity.
Implementation Method 1
The electromagnetic waves that propagate inside the IRE produce an evanescent field across the interfaces to the surrounding media (with n < nIRE) and may loose or gain energy by resonant excitation in the evanescent field region that penetrates into the adjacent low refractive index medium surrounding the IRE.
Implementation Method 2
The electromagnetic waves that propagate inside the IRE produce an evanescent field across the interfaces to the surrounding media and may loose or gain energy by resonant excitation in the evanescent field region that penetrates into the adjacent low refractive index medium surrounding the IRE.
Implementation Method 3
bonding of the analyte to specific (receptor) sites at the sensor surface
Data Source
AI summary
Optical sensor unit for infra red evanescence wave spectroscopy (IR-EWS) analysis of chemical and biological substances in an analyte, comprising a waveguide with a sensor surface to be put into contact with the analyte, wherein the sensor surface is provided with an affinity enhancing layer. There is further provided a method of producing an optical sensor unit.