Langmuir monolayers of non-soluble bioactive molecules can be used to study interactions of drugs, peptides, nucleic acids and other biomolecules that interact at the interface. See biomembranes and lipids section.
With LB and LS dipping it is possible to create immobilized biomolecular sensors and catalysts where biomolecules are embedded on a lipid layer to stabilize sensor molecule and prevent its denaturation. This can enhance the lifetime and activity of the molecules in question.
Specific examples from literature about immobilized proteins as sensors:
Immobilization of Alcohol Dehydrogenase in Phospholipid Langmuir-Blodgett Films To Detect Ethanol
Luciano Caseli, Angelo C. Perinotto, Tapani Viitala, Valtencir Zucolotto, and Osvaldo N. Oliveira, Jr.
Langmuir 2009, 25, 3057-3061
Alcohol dehydrogenase (ADH) mixed in dimyristoylphosphatidic acid (DMPA) monolayer exhibited enhanced transfer and detection ability towards ethanol compared to pure ADH layers. Studies proved that the ADH structure remained unchanged over one month in the mixed monolayer under storage conditions. A sensor array deposited on gold electrodes could detect alcohol down to 10 ppb concentration. For more details of the study please check the original publication.
Enhanced activity of horseradish peroxidase in Langmuir–Blodgett films of phospholipids
Thais F. Schmidt, Luciano Caseli, Tapani Viitala, Osvaldo N. Oliveira Jr.
Biochimica et Biophysica Acta 1778 (2008), 2291–2297
Horseradish peroxidase (HRP) was immobilized into Dipalmitoylphosphatidylglycerol (DPPG) supported layers by LB-technique. PM-IRRAS studies confirmed that the HRP inserted into the monolayer and was transferred onto a support without denaturation of the protein. HRP exhibited higher activity towards peroxides when incorporated into a monolayer than when in solution. For more details of the study please check the original publication.