Expert guidance on target product profile development for AMR diagnostic tests.

Diagnostics are widely considered crucial in the fight against antimicrobial resistance (AMR), which is expected to kill 10 million people annually by 2030. Nevertheless, there remains a substantial gap between the need for AMR diagnostics versus their development and implementation. To help address this problem, target product profiles (TPP) have been developed to focus developers' attention on the key aspects of AMR diagnostic tests. However, during discussion between a multisectoral working group of 51 international experts from industry, academia and healthcare, it was noted that specific AMR-related TPPs could be extended by incorporating the interdependencies between the key characteristics associated with the development of such TPPs. Subsequently, the working group identified 46 characteristics associated with six main categories (ie, Intended Use, Diagnostic Question, Test Description, Assay Protocol, Performance and Commercial). The interdependencies of these characteristics were then identified and mapped against each other to generate new insights for use by stakeholders. Specifically, it may not be possible for diagnostics developers to achieve all of the recommendations in every category of a TPP and this publication indicates how prioritising specific TPP characteristics during diagnostics development may influence (or not) a range of other TPP characteristics associated with the diagnostic. The use of such guidance, in conjunction with specific TPPs, could lead to more efficient AMR diagnostics development.

A new tool for routine testing of cellular protein expression: integration of cell staining and analysis of protein expression on a microfluidic chip-based system.

The key benefits of Lab-on-a-Chip technology are substantial time savings via an automation of lab processes, and a reduction in sample and reagent volumes required to perform analysis. In this article we present a new implementation of cell assays on disposable microfluidic chips. The applications are based on the controlled movement of cells by pressure-driven flow in microfluidic channels and two-color fluorescence detection of single cells. This new technology allows for simple flow cytometric studies of cells in a microfluidic chip-based system. In addition, we developed staining procedures that work "on-chip," thus eliminating time-consuming washing steps. Cells and staining-reagents are loaded directly onto the microfluidic chip and analysis can start after a short incubation time. These procedures require only a fraction of the staining reagents generally needed for flow cytometry and only 30,000 cells per sample, demonstrating the advantages of microfluidic technology. The specific advantage of an on-chip staining reaction is the amount of time, cells, and reagents saved, which is of great importance when working with limited numbers of cells, e.g., primary cells or when needing to perform routine tests of cell cultures as a quality control step. Applications of this technology are antibody staining of proteins and determination of cell transfection efficiency by GFP expression. Results obtained with microfluidic chips, using standard cell lines and primary cells, show good correlation with data obtained using a conventional flow cytometer.

Cytometric analysis of protein expression and apoptosis in human primary cells with a novel microfluidic chip-based system.

BACKGROUND: Work with primary cells is inherently limited by source availability and life span in culture. Flow cytometry offers extensive analytical opportunities but generally requires high cell numbers for an experiment. METHODS: We have developed assays on a microfluidic system, which allow flow cytometric analysis of apoptosis and protein expression with a minimum number of fluorescently stained primary cells. In this setup, the cells are moved by pressure-driven flow inside a network of microfluidic channels and are analyzed individually by two-channel fluorescence detection. For some assays the staining reactions can be performed on-chip and the analysis is done without further washing steps. RESULTS: We have successfully applied the assays to evaluate (a) activation of E-selectin (CD62E) expression by interleukin-1beta in human umbilical vein endothelial cells (HUVECs), (b) induction of CD3 by phorbol-12-myristate-13-acetate in freshly prepared human peripheral blood lymphocytes, and (c) staurosporine-induced apoptosis in HUVEC and normal human dermal fibroblasts. CONCLUSIONS: Results obtained with the microfluidic system are in good correlation with data obtained using a standard flow cytometer, but demonstrate new dimensions in low reagent and cell consumption.