Method for fabrication and verification of conjugated nanoparticle-antibody tuning elements for multiplexed electrochemical biosensors

Abstract

There is a critical need for more accurate, highly sensitive and specific assay for disease diagnosis and management. A novel, multiplexed, single sensor using rapid and label free electrochemical impedance spectroscopy tuning method has been developed. The key challenges while monitoring multiple targets is frequency overlap. Here we describe the methods to circumvent the overlap, tune by use of nanoparticle (NP) and discuss the various fabrication and characterization methods to develop this technique. First sensors were fabricated using printed circuit board (PCB) technology and nickel and gold layers were electrodeposited onto the PCB sensors. An off-chip conjugation of gold NP's to molecular recognition elements (with verification technique) is described as well. A standard covalent immobilization of the molecular recognition elements is also discussed with quality control techniques. Finally use and verification of sensitivity and specificity is also presented. By use of gold NP's of various sizes, we have demonstrated the possibility and shown little loss of sensitivity and specificity in the molecular recognition of inflammatory markers as "model" targets for our tuning system. By selection of other sized NP's or NP's of various materials, the tuning effect can be further exploited. The novel platform technology developed could be utilized in critical care, clinical management and at home health and disease management.

Development of electrochemical methods to enzymatically detect traumatic brain injury biomarkers

“…Functionalization The process of preparing the GDE can be found in La Belle et al, 2013 and is illustrated in scheme 1, but is briefly described here: the GDE is cleaned using Al 2 O 3 polishing pads and sonicated in DI water for 20 mins, then the alkane-thiol self-assembling monolayer (1 mM 16-MHDA dissolved in ethanol) is incubated on the GDE surface for 1 hr. Next, a 10 mM EDC/80 mM NHS in PBS solution is placed on the GDE surface for 1 hr to prepare the carboxyl end of the 16-MHDA for protein attachment.…”

Electrochemical-Nucleic Acid Detection with Enhanced Specificity and Sensitivity

“…In addition, just PCR technology can experience false positive readings between 9 and 57% [11] and ultimately not meet the criteria of the WHO of being specific and sensitive. Electrochemical detection offers greater sensitivity of target at low concentration [18][19][20][21][22][23]. The combination of immobilizing the TP to the surface GDE has provided evidence of achieving the specifications of the WHO ASSURED criteria and stands as an important method of future point-of-care technology.…”

Enhancing Glycemic Control via Detection of Insulin Using Electrochemical Impedance Spectroscopy

“…The electron transfer resistance can be used to derive a calibration curve linking back to input concentration. 25,29 However, recently some researchers have demonstrated the use of a modified Randles circuit that implements a constant phase element (CPE) to model the capacitance. 20,23,30 CPE is commonly referred to as either a leaky or imperfect parallel plate capacitor (IPPC).…”