Luminometer automated

The development of automated luminometers is focused primarily on devices that achieve high sample throughput rates, typically through the use of 96 and 384 well microtitre plates. Whilst suited for many applications, these systems require a skilled operator and often do not provide rapid results when the time taken to prepare the microtitre plate is included in the assay time. An instrument that can perform on demand, automated, near real time analysis using a variety of luminescent assay protocols has been developed. The instrument has been designed to automate various luminescent assays including adenylate kinase (AK) assays and those that use magnetic separation steps in conjunction with bioluminescence. ... 

Multiplicities of infection (MOI) of 10 1 and 2x10 1 (Salmonella THP-1 cells) were used. Salmonella cells were harvested at 3500 rpm for 8 min, washed 3 times in PBS and resuspended in 200 pL fresh antibiotic free RPMI medium. Bacteria and THP-1 cells were incubated together for 40 min at 37 C and were then decanted into sterile tubes and washed twice in pre-warmed PBS. Colistin was added at 50 pg/mL to inactivate extracellular bacteria and 200 pL of the cultures were placed into a black, clear-bottomed 96 well-plate. 0.1% saponin was added at time 180 min where appropriate. Imx and lux cultures of S. Typhimurium DT104 were used as controls. Bioluminescence was measured over 24 hours in an automated luminometer (Anthos) at 37 °C. 

In summary, chemiluminescence is a sensitive, non-invasive technique that can measure reactive oxidant production by small numbers of neutrophils indeed, neutrophil-derived chemiluminescence can be detected in as little as 5 fA of unfractionated human blood. The assay is suitable for automation using either multichannel luminometers or luminescence microtitre plate readers. Many researchers, however, have questioned the usefulness of this technique because of the uncertainty of the nature of the oxidant(s) that are detected. Nevertheless, in view of the recent developments made towards the identification of the oxidants measured and the assay s ability to detect intracellular oxidant production, it is has an important place in the phagocyte research laboratory. 

Commercial luminometers range from low-cost manual single tube instruments to fully automated high-capacity machines and have been reviewed previously (10). However, application-specific requirements are rarely discussed, and the first-time user will require some guidance in matching an instrument to the chemistry or chemistries to be used. 

Chemiluminescence at ambient temperature in this study was obtained from circular samples 1.0" in diameter (average wt. 0.5g), irradiated to 5MR only, which were placed in the sample well of an apparatus with automated counting function (Turner Designs, Inc. Model 20 Luminometer). The light emission was measured for several time periods of 120 seconds each. Average values and standard deviations were then obtained with pocket calculators. 

In a luciferase assay a flash of light is generated that decays rapidly after the enzyme and substrates are combined. For this reason, the use of flash kits requires rapid measurement within 5 min upon substrate addition and since a screen requires processing large numbers of plates, a luminometer coupled with an automated plate stacker is also required unless luciferase kits optimized for extended signal duration are used. 

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