Recently reported nanofluidic diodes with highly nonlinear current-voltage characteristics offer a unique possibility to construct different biosensors. These sensors are based on local changes of the surface charge on walls of single conical nanopores induced by binding of an analyte. The analyte binding can be detected as a change of the ion current rectification of single nanopores defined as a ratio of currents for voltages of one polarity, and currents for voltages of the opposite polarity. In this Article we provided both modeling and experimental studies of various biosensing routes based on monitoring changes of the rectification degree in nanofluidic diodes used as a biosensing platform. A prototype of a sensor for the capsular poly γ-D-glutamic acid (γDPGA) from Bacillus anthracis is presented. The nanopore used for the sensing was locally modified with the monoclonal antibody for γDPGA. The proof of principle of the rectification degree based sensing was further shown by preparation of sensors for avidin and streptavidin. Our devices also allowed for determination of isoelectric point of the minute amounts of proteins immobilized on the surface.

Point-of-care (POC) diagnostics provide rapid actionable information for patient care at the time and site of an encounter with the health care system. The usual platform has been the lateral flow immunoassay. Recently, emerging molecular diagnostics have met requirements for speed, low cost, and ease of use for POC applications. A major driver for POC development is the ability to diagnose infectious diseases at sites with a limited infrastructure. The potential use in both wealthy and resource-limited settings has fueled an intense effort to build on existing technologies and to generate new technologies for the diagnosis of a broad spectrum of infectious diseases.KEYWORDS infectious disease, lateral flow immunoassay, molecular diagnostic, point-of-care, rapid tests A point-of-care (POC) test is performed at or near the site where a patient initially encounters the health care system, has a rapid turnaround time (approximately 15 min), and provides actionable information that can lead to a change in patient management. Rapid results reduce the need for multiple patient visits, enable timely treatment, and facilitate the containment of infectious disease outbreaks. POC diagnostics also reduce the reliance on presumptive treatment and thereby facilitate antibiotic stewardship. Rapid diagnostic tests work by detecting analytes that are found in or extracted from clinical samples. There are two primary types of analytes: microbial antigens and patient antibodies that are specific for microbial antigens. However, there are emerging molecular technologies that enable nucleic acid-based approaches at the POC. In this minireview, we describe the origins and evolution of rapid POC tests, highlight several recent developments, and identify future directions that will move the field forward. PASTPerhaps the first large-scale use of the immunoassay for the diagnosis of infectious disease was in a report in 1917 by Dochez and Avery that pneumococcal polysaccharide can be detected by immunoassay of serum and urine from patients with lobar pneumonia (1). In a prescient comment, the authors suggested that antigen detection could enable a rapid diagnosis of infection. Interest in the immunoassay for an antigen or antibody for the diagnosis of disease was accelerated with the high sensitivity provided by the radioimmunoassay (RIA) in 1960 (2) and the enzyme-linked immunoassay (ELISA) in 1971 (3, 4). Indeed, the ELISA remains the dominant immunoassay platform technology in the non-POC central laboratory setting. Moreover, with automation, the ELISA technology also enables high-throughput sample processing. However, the ELISA and RIA platforms are also time consuming, have moderate or high complexity that requires trained laboratory personnel, and are typically equipment intensive. As a consequence, these technologies are not suited for POC use.The promise of immunoassays such as ELISA and RIA for the diagnosis of disease prompted numerous individuals and biotechnology companies to find the means to

The murine monoclonal antibody (MAb) 18B7 [immunoglobulin G1(κ)] is in preclinical development for treatment ofCryptococcus neoformans infections. In anticipation of its use in humans, we defined the serological and biological properties of MAb 18B7 in detail. Structural comparison to the related protective MAb 2H1 revealed conservation of the antigen binding site despite several amino acid differences. MAb 18B7 was shown by immunofluorescence and agglutination studies to bind to all four serotypes of C. neoformans, opsonize C. neoformans serotypes A and D, enhance human and mouse effector cell antifungal activity, and activate the complement pathway leading to deposition of complement component 3 (C3) on the cryptococcal capsule. Administration of MAb 18B7 to mice led to rapid clearance of serum cryptococcal antigen and deposition in the liver and spleen. Immunohistochemical studies revealed that MAb 18B7 bound to capsular glucuronoxylomannan in infected mouse tissues. No reactivity of MAb 18B7 with normal human, rat, or mouse tissues was detected. The results show that both the variable and constant regions of MAb 18B7 are biologically functional and support the use of this MAb in human therapeutic trials.