Extended Kalman Filtering Projection Method to Reduce the 3σ Noise Value of Optical Biosensors

Abstract

Optical biosensors have experienced a rapid growth over the past decade because of their high sensitivity and the fact that they are label-free. Many optical biosensors rely on tracking the change in a resonance signal or an interference pattern caused by the change in refractive index that occurs upon binding to a target biomarker. The most commonly used method for tracking such a signal is based on fitting the data with an appropriate mathematical function, such as a harmonic function or a Fano, Gaussian, or Lorentz function. However, these functions have limited fitting efficiency because of the deformation of data from noise. Here, we introduce an extended Kalman filter projection (EKFP) method to address the problem of resonance tracking and demonstrate that it improves the tolerance to noise, reduces the 3σ noise value, and lowers the limit of detection (LOD). We utilize the method to process the data of experiments for detecting the binding of C-reactive protein in a urine matrix with a chirped guided mode resonance sensor and are able to improve the LOD from 10 to 1 pg/mL. Our method reduces the 3σ noise value of this measurement compared to a simple Fano fit from 1.303 to 0.015 pixels. These results demonstrate the significant advantage of the EKFP method to resolving noisy data of optical biosensors.

Beyond Q: The Importance of the Resonance Amplitude for Photonic Sensors

“…In order to further demonstrate the versatility and generality of our model, we also consider a microring resonator with a relatively high Q -factor, that is, more than 1 order of magnitude higher than the previous sensors based on GMR. More details about the design and fabrication of the microring resonator are reported in refs and . The sensor exhibits A (λ 0 ) ∼ 0.8 with λ 0 = 1585.8 nm (Figure a), while the simulated Q -factor is Q R ∼ 2.6 × 10 4 .…”

“…(a) Transmission spectra and (b) resonance amplitude change of a microring resonator in the Silicon on Insulator (SOI) technology for different refractive index values of the surrounding medium with n 0 = 1.31. Please note that the refractive index values are not equally spaced, hence the curve appears non-linear.…”

Inverse Designed Plasmonic Metasurface with ppb Optical Hydrogen Detection

“…The genericity of our strategy allows it to be combined with other optimization approaches, including the use of more sensitive transduction materials such as PdAu, 2,19,49,50 (eightfold more sensitive than Pd at low H 2 concentrations) or PdTa 51 alloys, and advanced data fittings capable of producing lower signal noise. 52 Furthermore, we have so far only explored a simple and generic figure-of-merit parameter during our optimization, namely the peaks shift divided by the linewidth. Our inverse design approach, however, also permits the optimization of nanoparticle arrays for sensing platforms using different readouts such as singlewavelength mode devices, 53,54 opening the door to low-cost, ultrasensitive platforms.…”

SARS-CoV-2 Tests: Bridging the Gap between Laboratory Sensors and Clinical Applications

“…Various methods are employed to optimize their signals together with computational algorithms for improving the signal-to-noise ratio (SNR) and the LoD. 112 In the next subsections, we review the main optical, electrical, and mechanical virus sensor devices that are currently being investigated and that can be adapted for SARS-CoV-2 detection, before reviewing those sensors that have already been used for SARS-CoV-2 detection in the section SARS-CoV-2 Electrical, Mechanical, and Optical Detection Technologies .…”

“…They include plasmonic optical transducers such as surface enhanced Raman spectroscopy (SERS) based lateral flow immunoassays (LFIAs), mechanical transducers such as quartz crystal microbalances (QCMs), and electrical transducers such as nanowire or graphene-based field-effect transistors and electrochemical sensors. Various methods are employed to optimize their signals together with computational algorithms for improving the signal-to-noise ratio (SNR) and the LoD . In the next subsections, we review the main optical, electrical, and mechanical virus sensor devices that are currently being investigated and that can be adapted for SARS-CoV-2 detection, before reviewing those sensors that have already been used for SARS-CoV-2 detection in the section SARS-CoV-2 Electrical, Mechanical, and Optical Detection Technologies.…”