Vala Sciences

Vala Sciences Inc’s Kinetic Image Cytometer (KIC) and CyteSeer(TM) cell analysis software provides a unique instrument/software platform for the high-throughput/high-content analysis of kinetic cell function. It is designed for use with cells that have been cultured 96-well plates that have been loaded with fluorescent intracellular calcium indicators such as fluo-4 (or, alternatively, dyes sensitive to membrane voltage), and also with a live-cell label for nuclei, such as Hoechst 33342. The plate is then placed on the stage of the microscopSe (or a robotic loading apparatus can be used for higher throughput applications); the KIC will then automatically navigate to each well, lower electrodes into the well, and deliver a programmable series of electrical stimuli, while simultaneously recording digital images from the cells at a high frame rate (e.g., 30 Hz). The KIC repeats the protocol for all wells specified by the user, and can be interfaced to automated plate-loaders for performing multi-plate screens. Following image acquisition, Vala’s CyteSeer(TM) provides a convenient and flexible program for analyzing and displaying data, and selecting subpopulations of cells based upon a large number of data parameters developed from the acquired images. Following analysis of the kinetic phenomenon, the cells can be fixed and labeled for a variety of biomarkers, as specified by the user in up to 3 fluorescence channels, and the plate re-imaged by the KIC. Thus, it is possible to analyze both kinetic function and biomarker expression in the same cells, providing an unprecedented opportunity to examine the relationship between biomarker expression and physiological function.

Muscles and neurons display rapidly occurring (kinetic) physiological functions related to contraction, or the transfer of information. A common feature of these processes is the action potential, a transient electrical depolarization of the plasma membrane which lasts a fraction of a second, that propagates across the cell body, and from one place to another within a cellular or tissue network. The action potential often triggers secondary events, which are also rapid and transient in nature, such as increases in intracellular calcium concentration. Examples of action potential-mediated functions include the rhythmic contraction of the heart, which are initiated and conducted by action potentials coupled to calcium transients in cardiac myocytes, and the communication between peripheral tissues, organs, and limbs with the central nervous system, as provided by action potentials that travel along networks of neurons. Currently, transient increases in intracellular calcium concentration can be observed by loading cells with fluorescent calcium indicators such as fluo-4, and, in certain cases, the action potentials, themselves, can be visualized with fluorescent voltage indicators. Notably, analysis methods for the study of such kinetic functions have traditionally been “low throughput”, due to technical difficulties associated with data acquisition (e.g., applying electrical stimulation to the cells to stimulate generation of action potentials while simultaneously recording fluorescent images from the cells), and with data analysis. Furthermore, culture cell model systems are characteristically heterogeneous, in nature, due to local variations within the cultures in protein expression and interactions with neighboring cells. Additionally, in the context of stem cells, heterogeneity commonly results from differentiation processes, that influence the ability or character of the response of the cells to electrical stimulation.

Very relevant to this subject is the emerging concept of “high-content analysis”, in which the term “high-content” refers to the wealth of information that can potentially be extracted from images of cells. An ideal instrument/analytical package for analyzing the effects of drugs, compounds, or genomic constructs on action potential and associated physiological phenomenon would combine automated methods for reliably stimulating action potentials, digital image acquisition at a speed sufficient to characterize the ensuing responses, and the capability to perform cell-by-cell analysis of selected subpopulations of cells within heterogeneous cultures.

Vala’s KIC not only represents a new concept in instrumentation for analysis of cell kinetic function, but also incorporates several major advances in microscope design, that lead to overall enhanced performance. KIC’s autofocus mechanism is the fastest, and most accurate autofocus system ever offered on a commercially available microscope. Additionally, the high-powered plasma discrete light engine - which is far brighter than mercury-lamps - combined with the state of the art camera, yields far shorter integration times than traditional workstations. Thus, Vala’s KIC provides researchers with an exceptionally functional tool applicable to a multitude of biological and medical applications, including cardiotoxicity, stem cell differentiation, chemical and genomic screening and lead compound characterization, and will enable researchers to usher in a new era of kinetic high-content cell analysis.