The case for multiparameter cytometry in neurobiology

Recent progress in cytometric technologies and their applications in ecotoxicology and environmental risk assessment

Environmental toxicology focuses on identifying and predicting impact of potentially toxic anthropogenic chemicals on biosphere at various levels of biological organization. Presently there is a significant drive to gain deeper understanding of cellular and sub-cellular mechanisms of ecotoxicity. Most notable is increased focus on elucidation of cellular-response networks, interactomes, and greater implementation of cell-based biotests using high-throughput procedures, while at the same time decreasing the reliance on standard animal models used in ecotoxicity testing. This is aimed at discovery and interpretation of molecular pathways of ecotoxicity at large scale. In this regard, the applications of cytometry are perhaps one of the most fundamental prospective analytical tools for the next generation and high-throughput ecotoxicology research. The diversity of this modern technology spans flow, laser-scanning, imaging, and more recently, Raman as well as mass cytometry. The cornerstone advantages of cytometry include the possibility of multi-parameter measurements, gating and rapid analysis. Cytometry overcomes, thus, limitations of traditional bulk techniques such as spectrophotometry or gel-based techniques that average the results from pooled cell populations or small model organisms. Novel technologies such as cell imaging in flow, laser scanning cytometry, as well as mass cytometry provide innovative and tremendously powerful capabilities to analyze cells, tissues as well as to perform in situ analysis of small model organisms. In this review, we outline cytometry as a tremendously diverse field that is still vastly underutilized and often largely unknown in environmental sciences. The main motivation of this work is to highlight the potential and wide-reaching applications of cytometry in ecotoxicology, guide environmental scientists in the technological aspects as well as popularize its broader adoption in environmental risk assessment.

Multiparameter Lab-on-a-Chip flow cytometry of the cell cycle

Multiparameter analysis of apoptosis in relation to cell cycle position is helpful in exploring mechanism of action of anticancer drugs that target specific molecular cogs of the cell cycle. This work demonstrates a new rationale for using microfluidic Lab-on-a-Chip flow cytometry (μFCM) with a simple 2D hydrodynamic focusing for the multiparameter analysis of apoptosis and DNA ploidy analysis in human hematopoietic cancer cells. The microfluidic system employs disposable microfluidic cartridges fabricated using injection moulding in optically transparent poly(methylmethacrylate). The dedicated and miniaturized electronic hardware interface enables up to six parameter detections using a combination of spatially separated solid-state 473 nm (10 mW) and 640 nm (20 mW) lasers and x-y stage for rapid laser alignment adjustment. We provide evidence that the simple 2D flow focusing on a chip-based device is sufficient to measure cellular DNA content in both fixed and living tumor cells. The feasibility of using the μFCM system for multiparameter analysis of caspase activation and dissipation of mitochondrial inner membrane potential (ΔΨ(m) loss) in relation to DNA content is also demonstrated. The data shows that straightforward microfluidic chip designs are sufficient to acquire high quality biological data when combined with sophisticated electronic interfaces. They can be a viable alternative to conventional FCM for multiparameter detection of programmed cell death.