Microplates based on liquid bridges between glass rods

Abstract

Microplating that (i) does not necessitate complex or precise machinery to dispense small liquid volumes, (ii) enables fluorescent optical diagnosis, and (iii) permits simple analyte mixing mechanically is desirable. We advance here a novel approach that employs the formation of a liquid bridge held in place by capillary forces between glass rod tubes located parallel to each other. Experimental investigations made on liquid filling characteristics show conformance to theoretical notions. Analytical development showed the presence of regions of minimal uncertainty in the cross-sectional area of the liquid body arising from variations in the contact angle which permit consistent fluorescence measurements. Cyclical translation of the rods relative to each other, which cause rupture and reattachment of the liquid bridge, was found to engender good mixing. Strong linear trends were found in fluorescence signals relative to EGFP fluorophore concentration using standard and optical fiber (which offer targeted) excitation illumination. The open nature of liquid handling in the approach reported here and the positive results obtained portend the ability for development as integrated lab-on-a-chip devices.