Nozzle design parameters and their effects on rapid sample delivery in flow cytometry

Background: Rapid kinetic and high throughput flow cytometry are emerging as valuable tools in biotechnology research applications ranging from mechanistic analysis of molecular assemblies to high throughput screening. Many of these new applications have been made possible by improved sample delivery capabilities, focusing increased attention on fluidic issues associated with rapid sample delivery. Methods: Using basic fluidic premises, we derived a model that predicted the effect of nozzle parameters during rapid sample delivery. We tested the model using the rapid mix flow cytometer and modifications were made to the equipment to optimize performance. Results: The model predicted that shorter nozzles with wide exit orifices decrease the delay before initial particle analysis and the fluidic stabilization time. Experimental results confirmed thus prediction and model-based modifications allowed analysis of particles within 55 ms or 600 ms after mixing, with or without electronic gating, respectively. Conclusions: The model along with modifications to commercial equipment will allow rapid mix flow cytometry to analyze reactions in time frames threefold shorter than previously possible. The model allows for nozzle design predictions that should allow for analysis in the millisecond time frame. Furthermore, these findings are general for all rapid delivery applications, including high throughput flow cytometry. Cytometry 47:127-137, 2002. (C) 2002 Wiley-Liss, Inc.