Probe Drum will stream-line your everyday tasks of pipetting and absorbance measurements, synchronizing and integrating them with an analysis package to enhance the precision and reach of your results and the scope of your research.

Possible applications include pH-titrations, equilibrium ligand-binding assays, enzyme kinetics, protein stability assessment, calibration of spectroscopic probes or any other spectroscopic investigations that include in-line, step-wise change of the chemical or physical environment of your sample.

Example: The Antiviral Drug Target M2 from Influenza A

The transmembrane protein M2 plays a pivotal role in the infection of healthy cells by the influenza virus. By opening to an inflow of protons, it triggers a series of chemical reactions that lead to viral takeover of the host cell. A key step to deciphering the M2 mechansim, and thereby developing therapeutic agents that inhibit it, is quantifying the flow of protons through the protein under different conditions.

The M2 protein was reconstituted in liposomes, serving as a model for the virus, and a pH-sensitive nanoprobe was encapsulated in the liposomes. Using Probe Drum, the pH outside the liposomes was gradually changed, ading more and more protons. While titrating, Probe Drum monitored the pH inside the liposomes, using the optical signal from the pH probe inside. This way, the flow of protons from outside to inside was quantified.

The ease and precision with which Probe Drum performed these investigations made it possible to scan many different conditions – particularly, many different ionic strenghts. These experiments led to the conclusion that M2 not only transports protons, but exchanges them for other ions, antiporter-like. This is a key insight in the functionality of this protein, which helps us understand how to combat viral infection.

Read the full story in PNAS:

Proton and cation transport activity of the M2 proton channel from influenza A virus. Leiding, T.; Wang, J.; Martinsson, J.; DeGrado, W.F.; Peterson Årsköld, S. Proceedings of the National Academy of Sciences of the United States of America (2010) 107 15409-15414. DOI: 10.1073/pnas.1009997107

pH Titration with Feedback.

Set your desired pH range and step size, and press Go! For each point in the experiment, Probe Drum will calculate the appropriate amount of acid or base to add, add it, detect the achieved pH with the electrode, and adjust the addition if necessary. After the desired pH has been reached and stabilized in each point, the preset spectra will be recorded, reporting on the sample status at each point. The result is a thorough map of sample properties vs. pH.