Design of ultra-high sensitive biosensor to detect E. Coli in water
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ORIGINAL RESEARCH
Design of ultra-high sensitive biosensor to detect E. Coli in water Sandip Kumar Roy1
•
Preeta Sharan2
Received: 22 March 2019 / Accepted: 3 July 2019 Ó Bharati Vidyapeeth’s Institute of Computer Applications and Management 2019
Abstract Escherichia coli (abbreviated as E. coli) are bacteria found in water, in food. The present work focuses applications of surface plasmon resonance (SPR) based biosensors to detect E. coli. SPR is a label-free technology that is used to detect biological samples. The SPR based biosensor design consists of optical wave guide with different structures of metal–dielectric interfaces and effort has been done to optimize design parameters for improved sensitivity. Metal-dielectric structures considered are Au– Si, Ag–Si, Au–GaAs and Ag–GaAs. Obtained simulation results indicates that the performance of the proposed sensor can be enhanced by varying the thickness and material of metal–dielectric interfaces. The device sensitivity obtained 1071.42 nm/RIU by considering metal-dielectric interface of Gold (thickness 0.074 lm) and Gallium Arsenide (thickness 0.22 lm). This result is significantly higher than sensitivity value of 250 nm/RIU found in published literature for similar type of sensor. From the simulation graph it is clear that for small change in refractive index (RI), value of 0.07 (1.33–1.4), there is significant shift in wavelength. This shows that the sensor is highly sensitive towards the change in RI and can be fabricated as lab-on-chip based biosensor. The optimized sensor was tested for detection for E. coli and sensitivity of 400 nm/RIU obtained. The design is compact and easy to fabricate using optical lithography as compared to the conventional optical component based SPR sensor. & Sandip Kumar Roy [email protected] Preeta Sharan [email protected] 1
AMC Engineering College, Bangalore, India
2
The Oxford College of Engineering, Bangalore, India
Keywords SPR E. Coli Biosensor FDTD Lab-onchip Refractive index
1 Introduction Escherichia coli detection is the first step to eradicate them. Biosensors provides an alternative for E. Coli detection. When source of water is contaminated with infected human feces, the water can spread the E. Coli. Conventional methods are useful for the water borne microorganism’s detection but the limitations are there as many microorganism hide behind the overgrowth of faster growing microorganism. Some of these methods involve lengthy procedure and long duration to get results. Conventional technique such as fluorescence or ELISA (enzyme linked immuno-sorbent assay) requires special characteristics and labels (Radioactive or Fluorescent). ELISA is limited, particularly for applications involving complex media. Binding constants measured by ELISA are inherently flawed by two factors—immobilized binding partner and during the wash cycles of an ELISA, there will be significant loss of bound antibody. Biosensors are devices consists of a sensing element and interfaces to display result. Technology driver
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