Presentation Title

Development of Optical Fiber Biosensors for Detection of Methicillin-resistant Staphylococcus aureus

Start Date

November 2016

End Date

November 2016

Location

Watkins 2141

Type of Presentation

Oral Talk

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most difficult-to-treat infections. Its methicillin-resistance, encoded by mecA, protects it from beta-lactam antibiotics. Current diagnostic techniques are very slow and are performed only by trained personnel. We are developing a rapid detection method for MRSA using tapered fiber optic biosensors, which we have recently demonstrated for detection of binding between immunoglobulin-G (IgG) and anti-IgG (Miller, et al., Biosensors 2015, 5(2), 158-171). This method does not require any fluorescent labels and allows for real time detection in less than 3 hours. MRSA is detected by a hybridization reaction between immobilized mecA probes on the tapered fiber sensor surface and target complimentary mecA (prepared by heat-treatment and lysostaphin cell lysis of S. aureus). As hybridization occurs, the nanolayer formed modifies the refractive index of the sensor surface. This changes the way the modes of light within the fiber propagate with respect to each other, resulting in a measurable shift in the sinusoidal optical spectrum. The amount of shifting in the spectra allows us to infer whether or not hybridization has successfully occurred. In our preliminary experiments, we found that both mecA+ and mecA- generated large sensor signals. Further tests indicated a foundational problem between the DNA and its ability to bind onto the sensor surface. We are currently testing our functionalization steps, fabrication method, and experimental setup for possible problems. We will present results from our preliminary tests, subsequent control tests, and future aims of the project.

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Nov 12th, 11:00 AM Nov 12th, 11:15 AM

Development of Optical Fiber Biosensors for Detection of Methicillin-resistant Staphylococcus aureus

Watkins 2141

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most difficult-to-treat infections. Its methicillin-resistance, encoded by mecA, protects it from beta-lactam antibiotics. Current diagnostic techniques are very slow and are performed only by trained personnel. We are developing a rapid detection method for MRSA using tapered fiber optic biosensors, which we have recently demonstrated for detection of binding between immunoglobulin-G (IgG) and anti-IgG (Miller, et al., Biosensors 2015, 5(2), 158-171). This method does not require any fluorescent labels and allows for real time detection in less than 3 hours. MRSA is detected by a hybridization reaction between immobilized mecA probes on the tapered fiber sensor surface and target complimentary mecA (prepared by heat-treatment and lysostaphin cell lysis of S. aureus). As hybridization occurs, the nanolayer formed modifies the refractive index of the sensor surface. This changes the way the modes of light within the fiber propagate with respect to each other, resulting in a measurable shift in the sinusoidal optical spectrum. The amount of shifting in the spectra allows us to infer whether or not hybridization has successfully occurred. In our preliminary experiments, we found that both mecA+ and mecA- generated large sensor signals. Further tests indicated a foundational problem between the DNA and its ability to bind onto the sensor surface. We are currently testing our functionalization steps, fabrication method, and experimental setup for possible problems. We will present results from our preliminary tests, subsequent control tests, and future aims of the project.