MLSC is an alternative to flow cytometry that has many advantages in clinical environments such as minimal sample preparation, low sample volume, and direct measurement of absolute cell counts. However, MLSC requires an added image- processing step to produce the industry-standard FCS output format. The image processing program needs to handle multiple binary images, representing different detection channels; it needs to determine the background fluorescence level in each channel; the overall noise in each channel such that it can enumerate cell from noise; it needs to ignore extraneous signal such as bubbles, dust particles and other artifacts; and it needs to characterize each recognized cell to report parameters such as weighted flux, size, ellipticity, and ratios and correlations between the signal in other channels at the same location. We have developed an image processing solution, SurroImage that meets the above criteria and performs well in a clinical research setting.
Modern chemical synthesis and screening technologies have the ability to create large numbers of lead components but still do not answer questions of efficacy, dosing, toxicity and optimal patient population. SurroMed was founded to develop discovery technologies for new biological markers that will answer these questions. Biological markers will be derived from the results of many different assays; cell surface, serum factors and others, many performed using whole blood and other fluids and tissues. We report on the design of a Microvolume Laser Scanning Cytometer (MLSC) and disposable capillary arrays to be used in biological marker discovery. The MLSC machines are used primarily for cell surface assays, though they are suitable for other fluorescence assays as well. Each capillary requires a very small sample volume per assay, less than twenty micro- liters, and so allows hundreds of assays to be performed on a single ten milliliter blood draw. The new MLSC is capable of optimally detecting four fluorescence colors at different scan rates. HeNe excitation and red emission permits the use of whole blood, so that no lysing or cell separation is required. The MLSC instrument and disposable capillary arrays are in routine use for biological marker discovery at SurroMed.