This work presents a sandwich-type electrochemical impedance immunosensor for discovering toxin

This work presents a sandwich-type electrochemical impedance immunosensor for discovering toxin A (TcdA) and toxin B (TcdB). and TcdB was found to be 0.61 pg/mL and 0.60 pg/mL respectively at a signal-to-noise ratio of 3 (S/N = 3). This method is simple, fast and ultrasensitive, thus possesses a great potential for clinical applications in the future. is a spore-forming, gram-positive and anaerobic bacterium. It is the major cause of antibiotic-associated diarrhea and almost all cases of pseudomembranous colitis [1]. During the infection, two exotoxins with similar structure and function were released by most pathogenic strains of infection (CDI) is increasing dramatically during the past few years, early diagnosis is essential for better control and management of CDI, therefore, much research has been focused on the fast treatment and diagnosis of CDI in hospital settings [4C6]. The VX-680 analysis of CDI is principally predicated on medical features and laboratory recognition of microorganisms and poisons [7]. Methods currently in use for the organism identification include stool culture, the detection of glutamate dehydrogenase (GDH), and polymerase chain reaction (PCR) [8]. The toxin A&B detection assays are to detect the two toxins produced by bacteria in a stool sample. There are two main assays: tissue culture assay [9,10] and enzyme immunoassay (EIA) [11,12]. A rapid and simple test with high sensitivity and VX-680 specificity for detecting toxins is still challenging but highly desirable. In recent years, electrochemical biosensors have attracted considerable interest because of their intrinsic advantages such as high sensitivity, fast response, easy operation, favorable portability, and low cost [13]. Much effort has been made to design electrochemical biosensors with different technologies such as cyclic voltammetry (CV), chronoamperometry, chronopotentiomery, electrochemical impedance spectroscopy (EIS), and field-effect transistor (FET) [14]. Among these electrochemical methods, EIS is a rapid and nondestructive method with the ability to study the interfacial behavior of a wide range of materials in electrochemical system [15,16]. The electrode accessibility to the solution-based redox probe will be reduced due to the attachment of electrically insulated molecules, thus this technology is very useful to study the biorecognition event through capacitance, reactance and/or resistance changes at the electrode surface [17,18]. The electrochemical impedance immunosensors combining EIS and immunoassay have attracted extensive interest in many areas, including food industry, environmental pollution, diagnosis, biotechnology, pharmaceutical chemistry, and clinical diagnostics [19C21]. Meanwhile, researchers found that analytical signals of electrochemical impedance biosensor can be amplified by various strategies including the use of biotinCavidin/streptavidin system [16,22] and the generation of biocatalytic precipitation on the electrode surface [23]. On the other hand, it is worthy to note that with the Rabbit polyclonal to ISLR. increased understanding of nanomaterials, considerable efforts have been directed toward the design of different nanomaterial-based amplification paths aimed at achieving ultrahigh sensitivity [24C26]. For example, the application of semiconductor quantum dots (CdS) as oligonucleotide labeling tags for the detection of the target DNA by using EIS [27], which allows EIS signal to be amplified by space resistance and negative charges provided by the nanoconjugates. As one of the most used nanomaterials in biomedical research and clinical imaging [28] broadly, yellow metal nanoparticles (Au NPs) have already been addressed being a guaranteeing nanomaterial for the sign amplification in EIS evaluation for their great biocompatibility and simple self-assembly through a thiol group [29,30]. It’s been reported that the usage of antibody modified yellow metal nanoparticles is advantageous to immobilize even more antibody onto the electrode [31]. The sterical hindrance, aswell as the elevated quantity of antibody generated by the current presence of the antibody-gold conjugates may be used to enhance the awareness of electrochemical impedance immunosensors [32,33]. Up to now, there is absolutely no record on the use of electrochemical impedance immunosensors for discovering VX-680 TcdA and.