Polarization Interferometric Sensor for Label-Free Molecular Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current bio- and chemical sensors face challenges in detecting molecular interactions without using labels, which can perturb the dynamics of these interactions, and require high sensitivity to detect molecules present at low concentrations or in small quantities, especially in complex samples like combinatorial chemistry libraries.
Innovation Solution
A system utilizing a light source, optical retarder, and polarizing beam splitter to measure the phase shift between orthogonal polarization components under Total Internal Reflection or Frustrated Total Internal Reflection conditions, allowing for sensitive detection of refractive index changes and molecular binding, using a coherent light beam with orthogonal linear polarizations and a signal processor to calculate phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If label-free detection is used to avoid perturbing molecular interactions, then the natural dynamics of molecular interactions are preserved, but the sensitivity required to detect low concentration molecules becomes significantly more challenging
Solution Approach 1:
The patent changes the measurement parameter from intensity-based detection to phase shift detection between orthogonal polarization components. By measuring the phase difference induced by refractive index changes at the sensor surface, the system achieves high sensitivity (detecting 50 femtograms or 2,230,000 molecules) without using labels that would perturb molecular interactions.
Solution Approach 2:
The patent introduces a new measurement dimension by utilizing polarization-based interferometry. Instead of measuring single-intensity signals, the system measures the phase shift between two orthogonal polarization components (p and s polarizations), adding a dimensional aspect to the detection that enhances sensitivity while maintaining label-free operation.
2Measurement precision
If conventional sensors are used to detect molecules at low concentrations, then detection capability is reduced, but using label-free technologies increases complexity in achieving required sensitivity
Solution Approach 1:
The patent introduces an optical retarder as an intermediary component that provides a variable phase shift between the orthogonal polarization components. This intermediary element enables precise control and measurement of phase differences, achieving high detection sensitivity (5×10−8 Refractive Index Units) while maintaining a manageable system architecture through well-established optical components.
3Measurement precision
If high sensitivity detection is implemented to detect precious amounts of molecules, then detection capability improves, but the ability to handle high throughput screening becomes more challenging
Solution Approach 1:
The patent creates a universal detection platform that can simultaneously achieve high sensitivity (detecting 50 femtograms) and high throughput screening. The polarization-based interferometric sensor can be integrated with automated fluid handling and multi-well plate systems, allowing the same optical detection mechanism to serve both ultra-sensitive detection and high-volume screening applications in drug development and combinatorial chemistry.
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
This approach enables detection of surface refractive index changes as low as 5×10−8 Refractive Index Units, allowing for the detection of 50 femtograms or 2,230,000 molecules of a 100 amino acid peptide, with high sensitivity and specificity, suitable for high-throughput screening and applications in infectious disease detection, drug development, and industrial quality control.
Implementation Method 1
an optical retarder for providing a variable phase shift between the first and second lightwaves by imposing a relative delay between the first and the second lightwaves
Implementation Method 2
a prism interface for reflecting the first light beam from the sample material under Total Internal Reflection (TIR) or Frustrated Total Internal Reflection (FTR) conditions
Data Source
AI summary
A sensor and method for determining the optical properties of a sample material is disclosed. The sensor comprises a light source that generates a linearly polarized light beam having a predetermined polarization orientation with respect to the plane of incidence. The linearly polarized light beam is reflected off the sample and is split into second and third light beams where the second and third light beam consist of the combined projections of mutually orthogonal components of the first light beam. A signal processor measures the intensity difference between the second and third light beams to calculate the phase difference induced by the sample material.