Detection of Salmonella Typhimurium on Spinach Using Phage-Based Magnetoelastic Biosensors.

Phage-based magnetoelastic (ME) biosensors have been studied as an in-situ, real-time, wireless, direct detection method of foodborne pathogens in recent years. This paper investigates an ME biosensor method for the detection of Typhimurium on fresh spinach leaves. A procedure to obtain a concentrated suspension of from contaminated spinach leaves is described that is based on methods outlined in the U.

A surface-scanning coil detector for real-time, in-situ detection of bacteria on fresh food surfaces.

Proof-in-principle of a new surface-scanning coil detector has been demonstrated. This new coil detector excites and measures the resonant frequency of free-standing magnetoelastic (ME) biosensors that may now be placed outside the coil boundaries. With this coil design, the biosensors are no longer required to be placed inside the coil before frequency measurement.

Rapid and sensitive detection of Salmonella Typhimurium on eggshells by using wireless biosensors.

This article presents rapid, sensitive, direct detection of Salmonella Typhimurium on eggshells by using wireless magnetoelastic (ME) biosensors. The biosensor consists of a freestanding, strip-shaped ME resonator as the signal transducer and the E2 phage as the biomolecular recognition element that selectively binds with Salmonella Typhimurium. This ME biosensor is a type of mass-sensitive biosensor that can be wirelessly actuated into mechanical resonance by an externally applied timevarying magnetic field.

Effects of surface functionalization on the surface phage coverage and the subsequent performance of phage-immobilized magnetoelastic biosensors.

One of the important applications for which phage-immobilized magnetoelastic (ME) biosensors are being developed is the wireless, on-site detection of pathogenic bacteria for food safety and bio-security. Until now, such biosensors have been constructed by immobilizing a landscape phage probe on gold-coated ME resonators via physical adsorption. Although the physical adsorption method is simple, the immobilization stability and surface coverage of phage probes on differently functionalized sensor surfaces need to be evaluated as a potential way to enhance the detection capabilities of the biosensors.

Time domain characterization of magnetoelastic sensors: A pulse method for resonance frequency determination.

This paper presents a pulse method for determination of resonance frequency of magnetoelastic sensors. The method eliminates the bias field that is necessary in previous methods and also allows fast and accurate detection. The stability tests of the system show an average standard deviation of 129 Hz and an average drift of -10.

Direct detection of Salmonella typhimurium on fresh produce using phage-based magnetoelastic biosensors.

Current bacterial detection methods require the collection of samples followed by preparation and analysis in the laboratory, both time and labour consuming steps. More importantly, because of cost, only a limited number of samples can be taken and analyzed. This paper presents the results of an investigation to directly detect Salmonella typhimurium on fresh tomato surfaces using phage-based magnetoelastic (ME) biosensors.

Zero-order therapeutic release from imprinted hydrogel contact lenses within in vitro physiological ocular tear flow.

Zero-order or concentration independent release kinetics are highly desirable from drug delivery devices. In this paper we demonstrate experimentally, for the first time, zero-order release of a small molecular weight therapeutic, ketotifen fumarate (MW=425), from molecularly imprinted hydrogels used as therapeutic contact lenses. We performed dynamic, in vitro drug release studies from imprinted hydrogel contact lenses within a novel microfluidic device that simulates the volumetric flow rates, tear volume and tear composition of the eye.