High resolution fluorescence imaging with cantilevered near-field fiber optic probes

High resolution near-field fluorescence and topology images of intact neurons are reported using a cantilevered near-field fiber optic probe. A bend is introduced into a normal geometry near-field tip, allowing the probe to be used in a tapping-mode arrangement, similar to tapping-mode atomic force microscopy. Features with a full width at half-maximum of 140 nm are observed in the near-field fluorescence image, demonstrating the subdiffraction Limit spatial resolution possible with the cantilevered near-field probe design. Characteristics of the cantilevered tips include resonances between 30 and 60 kHz, Q factors greater than 100, and measured spring constants of 300 to 400 N/m. (C) 1996 American Institute of Physics.