Peyman Jahanshahi

Rapid Immunoglobulin M-Based Dengue Diagnostic Test Using Surface Plasmon Resonance Biosensor

Surface plasmon resonance (SPR) is a medical diagnosis technique with high sensitivity and specificity. In this research, a new method based on SPR is proposed for rapid, 10-minute detection of the anti-dengue virus in human serum samples. This novel technique, known as rapid immunoglobulin M (IgM)-based dengue diagnostic test, can be utilized quickly and easily at the point of care. Four dengue virus serotypes were used as ligands on a biochip. According to the results, a serum volume of only 1 μl from a dengue patient (as a minimized volume) is required to indicate SPR angle variation to determine the ratio of each dengue serotype in samples with 83–93% sensitivity and 100% specificity.

Analysis and experiment of centrifugal force for microfluidic ELISA CD platform

This paper presents an analysis and experiment of centrifugal force for microfluidic Enzyme-Linked Immunosorbent Assay (ELISA) on a compact-disc (CD) platform. The ELISA CD was designed based on the centrifugal force as a driving force while capillary force acts as preventing barrier. The CD composed of 2 layers: the substrate layer is made of PMMA and the top layer is laminated with an Adhesive Sealing Films (ASF) or thermal seal. The PMMA substrate was fabricated by CNC micromachining. The ELISA CD consists of 7 reservoirs: waste, detection, serum, conjugate, washing solution, substrate and stopping solution. In the experiment, the reservoirs were filled with colour liquid and the fluid flow behaviour of the liquid in the CD was studied and monitored by a customized CD spin stand system equipped with visualization system. The experimental test results show an average of 9% error when compared with the theoretical calculation of burst frequency for all the reservoirs.

Development and Validation of Fiber Bragg Grating Sensing Pad for Interface Pressure Measurements Within Prosthetic Sockets

This paper presents an efficient fiber Bragg grating (FBG)-based sensing pad that is capable of measuring the interface pressure within prosthetic sockets, and exhibits required sensitivity, enhanced durability, and the lowest possible hysteresis error. Three key fabrication parameters were studied to assess their effects on the performance of different sensing pad designs. These parameters included the FBG embedding depth (top, bottom, and neutral layers of the sensing pad), the sensing pad thickness (1, 2, and 3 mm), and finally, different embedding materials. Each sensing pad was studied while attached to Pe-lite and silicone prosthetic liners. Afterward, the sensing pad design that exhibited the best performance was employed to fabricate an expandable array of FBGs for interface pressure measurements within prosthetic sockets. One transtibial amputee participated in this paper to further assess the in situ performance of the sensing pad. To validate the findings, the results were also compared with the pressure measurements using the F-socket sensors. The results revealed that the FBGs embedded in the neutral layer of harder and thicker sensing pads exhibited the highest sensitivity as well as excellent accuracy. In addition, they could successfully measure the interface pressure inside the prosthetic socket. Higher pressure values were logged by the FBG sensors compared with the F-socket. Yet, the trend of pressure changes was similar for both sensor types. This paper is hoped to form a robust platform for the researchers intending to utilize the FBG sensors in such applications.

Study on dielectric function models for surface plasmon resonance structure.

The most common permittivity function models are compared and identifying the best model for further studies is desired. For this study, simulations using several different models and an analytical analysis on a practical surface Plasmon structure were done with an accuracy of ∼94.4% with respect to experimental data. Finite element method, combined with dielectric properties extracted from the Brendel-Bormann function model, was utilized, the latter being chosen from a comparative study on four available models.

Kinetic analysis of IgM monoclonal antibodies for determination of dengue sample concentration using SPR technique.

ABSTRACT Surface plasmon resonance (SPR) sensing is recently emerging as a valuable technique for measuring the binding constants, association and dissociation rate constants, and stoichimetry for a binding interaction kinetics in a number of emerging biological areas. This technique can be applied to the study of immune system diseases in order to contribute to improved understanding and evaluation of binding parameters for a variety of interactions between antigens and antibodies biochemically and clinically. Since the binding constants determination of an anti-protein dengue antibody (Ab) to a protein dengue antigen (Ag) is mostly complicated, the SPR technique aids a determination of binding parameters directly for a variety of particular dengue Ag_Ab interactions in the real-time. The study highlights the doctrine of real-time dengue Ag_Ab interaction kinetics as well as to determine the binding parameters that is performed with SPR technique. In addition, this article presents a precise prediction as a reference curve for determination of dengue sample concentration.

Three-dimensional modeling of surface plasmon resonance based biosensor

The surface plasmon resonance (SPR) is one of the most attractive and precise enabling mechanism for sensors in biomedical applications. Conventional biological experiments are performed manually, time consuming intervention and expensive interconnection techniques. This paper simulates three dimensional behavior of magnetic and electric fields of light coupled into a SPR mode propagating along a thin gold layer surrounded by symmetric dielectric layers. This study successfully illustrates the three-dimensional simulation of surface plasmon wave using finite element method in COMSOL Multiphysics suit.

Study of Traps in Special Doped Optical Fiber Radiation Sensors via GlowCurve Analysis

Thermoluminescence dosimeters (TLDs) are widely used, serving the needs of various radiation applications. In recent times optical fibers have been introduced as alternatives to more conventional phosphor-based TLD systems, with many efforts being carried out to improve their thermoluminescence (TL) yield. While there have been extensive studies of many of the various TLD characteristics of optical fibers, including TL response, linearity, reproducibility, repeatability, sensitivity and fading, far more limited studies have concerned dependence on the type of TL activator used in optical fibers, promoting the TL mechanism. Present study focuses on TLD glow curves analysis for five different doped optical fibers that have been subjected to photon and electron irradiation. Trap parameters such as activation energy and frequency factors have been obtained from second order kinetics analysis, based on computerized glow curve deconvolution. An interesting observation is that co-doped fibers typically leads to enhanced TL characteristics, pointing to a need for optimization of the choice and levels in use of co-dopants.

Image Deconvolution by Means of Frequency Blur Invariant Concept

Different blur invariant descriptors have been proposed so far, which are either in the spatial domain or based on the properties available in the moment domain. In this paper, a frequency framework is proposed to develop blur invariant features that are used to deconvolve a degraded image caused by a Gaussian blur. These descriptors are obtained by establishing an equivalent relationship between the normalized Fourier transforms of the blurred and original images, both normalized by their respective fixed frequencies set to one. Advantage of using the proposed invariant descriptors is that it is possible to estimate both the point spread function (PSF) and the original image. The performance of frequency invariants will be demonstrated through experiments. An image deconvolution is done as an additional application to verify the proposed blur invariant features.

Development of a low-cost and portable device controller for point-of-care medical diagnostics

The field of centrifugal microfluidics aims to miniaturize common biochemical assays onto specialized discs (CDs). By the exploitation of the centrifugal force, centrifugal microfluidics CDs do not require the syringe pumps that stationary microfluidic platforms require. This paper describes the development of a low-cost and portable controller device that is capable of performing centrifugal microfluidics at the point-of-care (POC). Overall, this system aims to be low in cost, fast, and modular. In this study, the Spin-Stand device controller is the final product of three stages of development: design, virtual simulation and implementation. At the core of the system, the controller is designed to adjust the disc rotational speed for performing several operations by Pulse Width Modulation (PWM) through PIC (Programmable Interface Controller).

Analysis of optical fibre defects using thermoluminescence glow curve method

Knowledge about defects inside the optical waveg-uides is necessary to control the loss during the communication. Therefore the investigation of glow curve can be significant important for improvement of communication systems. In this research, the defects of a cylindrical optical fibre with 8% germanium doped is studied, and then the deconvolution of thermoluminescence glow curve is presented for this case study. This study offers a zero level noise as a reference for each experiment. In order to have a high accuracy of glow curve, this reference can help to calculate the final glow curve properly.