Development of an Analytical System Based Around a Miniature Fast Analyzer

Abstract

A modified version of a previously described miniature Fast Analyzer [Clin. Chem. 18, 753 (1972)] was used as the basis for developing a compact, potentially portable, analytical system. This system includes an automated and versatile sample-reagent loader, a miniature Fast Analyzer, several plastic rotors and their cleaning station, and a portable data system. The sample-reagent loader combines a unique turntable assembly and two "Micromedic" pipets to quickly (5 min per rotor), accurately, and precisely obtain, transfer, and dispense small volumes of sample (1 to 10 µl of sample, 50 µl of diluent) and reagent (20 µl of reagent, 50 µl of diluent) into their respective cavities in a 17-cuvet rotor. The loader uses separate sample and reagent carousels, which allows operation of the system in either the single-sample—multiple-chemistry, multiple-sample— single-chemistry, or multiple-sample—multiple-chemistry analytical modes. The miniature Fast Analyzer rotates a loaded 17-cuvet rotor through a stationary optical system at speeds up to 5000 rpm. The resulting centrifugal force is used to mix and to transfer the discrete aliquots of sample(s) and reagent(s) into their respective cuvets. The ensuing reactions are monitored photometrically, and the data are processed in real time by either a portable Data Processor [Clin Chem. 18, 762 (1972)] or an on-line computer. A major improvement to the analyzer has been the addition of a temperature-control system that allows the temperature of the spinning rotor to be monitored and controlled to within ±0.2°C. After completion of an analytical run, the rotor is automatically washed and dried in the rotor cleaning station. Many of the standard clinical analyses, including most of the NADH-linked enzymatic analyses, have been adapted for use with this system.

Challenges in the Use of Compact Disc-Based Centrifugal Microfluidics for Healthcare Diagnostics at the Extreme Point of Care

“…The movement of fluid through microscale channels by centripetal force has been studied and developed by researchers since the late 1960s [ 23 ]. Centrifugation as a method of actuation has been explored as an alternative to traditional pumps because its lack of need for extraneous equipment ( i.e ., syringes, tubing and syringe pumps), the ability to contain an entire assay on a single disc, and the ability to actuate many fluid types due to its independence of movement from physiochemical properties ( i.e ., pH or ionic strength) [ 19 , 21 ].…”

Enzyme changes associated with mitochondrial malic enzyme deficiency in mice

“…Enzyme~assays. Enzyme assays were performed utilizing the Miniature Centrifugal Fast Analyzer [17]. The enzymes glucose-6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.43), hexokinase (EC 2.7.1.1), lactate dehydrogenase (EC 1.1.1.27), pyruvate kinase (EC 2.7.1.40), glutathione reductase (EC 1.6.4.2), malate dehydrogenase (EC 1.1.1.37), and glutamic-oxaloacetic transaminase (EC 2.6.1.1) were assayed as described by Fielek and Mohrenweiser [18].…”

Automated processing of whole blood samples into microliter aliquots of plasma

“…The sampling disk, containing the capillaries filled with plasma, is then removed and the tip of each is carefully wiped with tissue. At this point, the disk can be placed into a modified analytical rotor for conventional centrifugal analysis, Burtis et al [2], or the capillaries can be removed individually for a variety of analyses.…”

“…The development was previously reported of a simple rotor for automatically processing individual, unmeasured aliquots of whole blood into measured, microliter aliquots of plasma, Burtis et al [1 ]. Evaluation of this device, designated the 'Capillary Processor and Aliquoter Model 1' (CPA-1), and its subsequent use with a centrifugal analyser, Burtis et al [2], demonstrated its capabili.ty for producing aliquots of plasma with a degree of precision approaching that of a mechanical pipette. The device has numerous applications; however, it was limited to producing a batch of single aliquots of plasma from single aliquots of whole blood.…”