Label-Free Quantitative Detection of Protein Using Macroporous Silicon Photonic Bandgap Biosensors

Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, United States
Analytical Chemistry (Impact Factor: 5.64). 03/2007; 79(4):1502-6. DOI: 10.1021/ac0608366
Source: PubMed


A label-free biosensor was demonstrated using macroporous silicon (pore size >100 nm) one-dimensional photonic band gap structures that are very sensitive to refractive index changes. In this study, we employed Tir-IBD (translocated Intimin receptor-Intimin binding domain) and Intimin-ECD (extracellular domain of Intimin) as the probe and target, respectively. These two recombinant proteins comprise the extracellular domains of two key proteins responsible for the pathogenicity of enteropathogenic Escherichia coli (EPEC). The optical response of the sensor was characterized so that the capture of Intimin-ECD could be quantitatively determined. Our result shows that the concentration sensitivity limit of the sensor is currently 4 microM of Intimin-ECD. This corresponds to a detection limit of approximately 130 fmol of Intimin-ECD. We have also investigated the dependence of the sensor performance on the Tir-IBD probe molecule concentration and the effect of immobilization on the Tir-IBD/Intimin-ECD equilibrium dissociation constant. A calibration curve generated from purified Intimin-ECD solutions was used to quantify the concentration of Intimin-ECD in an E. coli BL21 bacterial cell lysate, and results were validated using gel electrophoresis. This work demonstrates for the first time that a macroporous silicon microcavity sensor can be used to selectively and quantitatively detect a specific target protein with micromolar dissociation constant (Kd) in a milieu of bacterial proteins with minimal sample preparation.

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Available from: Lisa A Delouise, Jul 01, 2014
    • "dase from the bacteria by increasing the porosity of the cell membrane. These biosensors provide relatively high sensitivity for E. coli of 10 and 100 colony forming units/mL (CFU/mL) with detection time of 40 and 30 min, respectively. A label-free PSi optical biosensor for selective and quantitative detection of pathogenic E. coli was reported by Ouyang et al . (2007b)"

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    • "Detection limits as low as 50–250 pg/mm2 were achieved for the optimized macroporous silicon sensors—values which could compete with standard SPR devices. Two years later, in 2007, macroporous silicon microcavity photonic bandgap sensors were used for selective and quantitative detection of protein interactions [52]. "
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    Full-text · Article · Apr 2013 · Sensors
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    • "Over the past three decades, there is a great need for the development of easy-use, sensitive, robust and inexpensive biosensors for detection and identification of biological substances. Labelfree optical biosensors have been pursued with great interest by many researchers [1] [2] [3] [4]. Sensing platform such as Mach–Zehnder interferometer [5] [6], and surface plasma resonance [7] [8] have been employed in label-free affinity biosensors to measure the change of refractive index at the surface of the sensor upon binding of the target molecules to the bioreceptors. "
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    ABSTRACT: An ultrasensitive two-dimensional photonic crystal biosensor is theoretically demonstrated in this paper. Such device consists of a waveguide and high Q-value microcavities which are realized by introducing line and point defects into the photonic crystal respectively. The band structures and the transmission spectra are obtained from the Finite-Difference –Time-Domain (FDTD) method. The simulation results showed that such device is strongly sensitive to the refractive index of the analyte injected into the point defect. The designed device can be applied for measurements of the refractive index and detection of protein-concentrations.
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