AP-3000 is based on SPR(Surface Plasmon Resonance) and detects the binding of compounds as changes of refractive index. The smaller molecular weight of a compound is, the harder it is to detect it. But AP-3000, using a highly precise sensor/ light detection method which allows detection of signals at low noise, can detect signals of 6RU above a baseline, and determine the binding.

The sensor for AP-3000 is called a sensor stick because of its long and narrow shape. The sensor stick is composed of a prism covered with gold thin coating, a protein immobilization layer, and plastic flow-paths.

Complete sensor sticks are sold in a case. When it is time to be used, the case is placed at a specific area within the instrument, and the sensorsticks within the case are automatically moved and set at the detection unit.
One channel in a sensor stick is composed of an area for protein immobilization and a reference area. At the time of binding detection, the same solution is injected by exclusive pipette tips (Precise tips) first into the reference area and then into the protein immobilization area. The solution stays static except for the time of injection. The solution exchange rate is more than 99.9% and this helps produce the highly precise measurement.

AP-3000 offers a function to recover the solutions that are injected into flow-paths. This makes it possible to directly confirm the activity of an immobilized enzyme protein. The flow-paths are short and wide, and therefore they do not get clogged up, and the amount of sample used is small.

Spotfire DecisionSite for AP-3000 is the Spotfire DecisionSite with a module that exclusively analyzes the data taken on AP-3000. When AP-3000 is purchased, the software, Spotfire DecisionSite for AP-3000 comes with it, being installed on the data analysis computer externally connected to AP-3000. Regardless of having license or not, anybody can use the software on this data analysis computer.
Raw data taken by AP-3000 is read by Spotfire DecisionSite for AP-3000, and the software automatically performs visualization of the data, by adding information on proteins and compounds (name, molecular weight, concentration, and so on).
Types of visualization include:
- Histogram (Switching between binding values and binding activity values is possible.)
- Compound binding sonsorgram
- Dose response plot (Superimposed visualization for each compound)
- Protein immobilization sensorgram
- Trend graph for binding signals and baseline signals (at each protein immobilization area)
- Display of binding signals and baseline signals in a plate format.
Sometimes, while taking SPR measurement, adjusting the buffer causes shifting of all signals toward either plus or minus. In this case, using blank signals, Spotfire DecisionSite for AP-3000 can calculates the dissociation constant, KD from dose response plots and kd from the tilt of dissociation curves.
At the same time, AP-3000 has the following data correction functions to analyze binding signals taken from SPR measurements with precision.
- Blank signal correction function (to correct the phenomena of overall signals drifting toward either plus or minus, which is caused by buffer adjustment, by using blank signals.)
- Positive control correction function (to correct changes of binding signals caused by the activity loss of immobilized proteins, using positive control signals periodically measured.)
- Flag export function (to identify certain data in a result file and then export the identified information. Using this function, the compounds which are to be skipped are identified visually, and this information is transferred to the internal computer and used to automatically skip injection of those compounds into the sensors.)
Moreover, it is possible to calculate the affinity constant, KD from dose response plots and the dissociation rate constant, kd from the slope of dissociation curves.
Finally, the data that has been corrected and analyzed is stored in a Spotfire format (sfs file), and those users who have Spotfire DecisionSite licenses can view and share the results, using their own Spotfire DecisionSite.