Multiparametric Magneto-fluorescent Nanosensors for the Ultrasensitive Detection of Escherichia coli O157:H7

Abstract

Enterohemorrhagic Escherichia coli O157:H7 presents a serious threat to human health and sanitation and is a leading cause in many food- and waterborne ailments. While conventional bacterial detection methods such as PCR, fluorescent immunoassays and ELISA exhibit high sensitivity and specificity, they are relatively laborious and require sophisticated instruments. In addition, these methods often demand extensive sample preparation and have lengthy readout times. We propose a simpler and more sensitive diagnostic technique featuring multiparametric magneto-fluorescent nanosensors (MFnS). Through a combination of magnetic relaxation and fluorescence measurements, our nanosensors are able to detect bacterial contamination with concentrations as little as 1 colony-forming unit (CFU). The magnetic relaxation property of our MFnS allow for sensitive screening at low target CFU, which is complemented by fluorescence measurements of higher CFU samples. Together, these qualities allow for the detection and quantification of broad-spectrum contaminations in samples ranging from aquatic reservoirs to commercially produced food.

Highly Sensitive, Engineered Magnetic Nanosensors to Investigate the Ambiguous Activity of Zika Virus and Binding Receptors

“…After we verified the effectiveness of our platform using the antibody, we began to examine the interactions between ZENV and our selected receptors. MRNPs were functionalized with the extracellular domain of AXL, HSP70, and TIM-1, as previously described 4 , 5 . Our Z-Ab-MRNPs were used in order to comparatively analyze the binding between the suspected receptors.…”

“…While there is still much to be determined about this key stage, it has been demonstrated that the initial interactions between ZIKV and receptors expressed in various host cell populations is a critical determinant of ZIKV tropism 3 . It is for this reason that we have begun to investigate these host-pathogen interactions using our ultra-sensitive magnetic relaxation nanoplatform 4 , 5 .…”

Use of Nanomaterials in Food Science

“…Magnetic resonance can detect extremely low levels of bacteria, but it is almost ineffective at higher bacteria concentrations, while fluorescence is opposite. A hybrid nanosensor incorporating magnetic resonance and fluorescence has been developed to rapidly detect the presence of E. coli (Banerjee et al 2016). It has been reported that detector could sense different concentrations of a pathogenic strain of E. coli known as O157: H7 during test of milk in less than an hour.…”

Electrochemical Detection of E. coli O157:H7 in Water after Electrocatalytic and Ultraviolet Treatments Using a Polyguanine-Labeled Secondary Bead Sensor

“…Although highly effective at detecting the presence of STEC, PCR methods only detect the presence of bacteria and, do not directly differentiate between viable cells capable of producing Shiga toxins and inactivated non-pathogenic bacteria. A drawback to all of these methods is that the samples must be sent to sterile laboratories containing expensive and bulky equipment, managed by skilled labor [ 7 ]. These methods are cost and time restrictive for most POU users who require expedient results in a few hours, instead of days [ 8 , 9 ].…”