KSV NIMA
The KSV NIMA Surface Potential Sensor (SPOT) is used for determining molecular orientation changes in Langmuir films. Together with the surface pressure sensor included in all KSV NIMA Langmuir and Langmuir-Blodgett Troughs, it gives an in-depth view of the Langmuir monolayer interactions.
The KSV NIMA Surface Potential Sensor measures the potential difference above and below the film and is sensitive to the sum of all the individual dipole moments. The changes in surface potential are measured by detecting the potential difference between the vibrating plate, which is placed above the monolayer, and the counter electrode, which is immersed in the sub-phase below the monolayer.
The sensor allows complementing data from surface pressure—area isotherm measurements obtained from a Langmuir and Langmuir-Blodgett Trough. It allows the determination of monolayer composition, molecular orientation, degree of molecular dissociation and molecular interactions at the interface.
The KSV NIMA Surface Potential Sensor is recommended for use with a KSV NIMA Langmuir, Langmuir-Blodgett or Microscopy Trough to enable combined surface pressure and surface potential measurements. The SPOT can also be used with other troughs together with a KSV NIMA Interface Unit.
In drug discovery the permeation of the drug into cells through cell walls and the reaction of the drug within the cell membrane are important factors for drug efficiency. In this example, a drug candidate for the Human African Sleeping Sickness (HAT) was studied in vitro in a model cell membrane.
The oligopeptide-based drug S-(2,4-dinitrophenyl) glutathione di-2-propyl ester, has shown activity in the treatment of HAT and was studied in Langmuir monolayer model membrane of DPPC (dipalmitoyl phosphorylcholine), an abundant lipid in the protozoan membrane. The monolayer properties of the drug itself and its interactions with DPPC monolayers were studied with Langmuir equipment with a surface potential meter and polarization modulation surface infrared reflection absorption spectrometer.
Surface pressure-area and surface potential-area isotherms of a HAT-drug monolayer at air-buffer interface.
For more information see Resources tab.
Application Note — Interactions of Biomolecules in Cell Membrane Models