Conventional far-field infrared microscopes have limitations in spatial resolution due to the diffraction limit, which restricts the analysis of small objects like intracellular structures, crystals, interfaces, and proteins. To overcome this limitation, a technique called AFM-IR was developed by combining atomic force microscopy (AFM) and infrared spectroscopy (IR). This method involves using a pulsed IR laser source directed at the area beneath the AFM cantilever, which generates IR radiation that is absorbed by the sample. The resulting thermal expansion is detected by the highly sensitive AFM cantilever, allowing for near-field detection that bypasses the diffraction limit. AFM-IR can achieve resolutions of up to 20 nm in contact mode and 10 nm in tapping mode, making it a powerful tool for analyzing small samples with high precision.
– Bioavailability assays
– Single molecule localizations & diffusion studies