Photonic force microscope based on optical tweezers and two-photon excitation for biological applications.
J Struct Biol
; 119(2): 202-11, 1997 Jul.
Article
en En
| MEDLINE
| ID: mdl-9245760
ABSTRACT
A new scanning probe microscope, the photonic force microscope (PFM), based on optical tweezers and two-photon absorption processes for biological applications is described. Optical tweezers are used to trap a fluorescent latex bead with a diameter of 200 nm in an aqueous solution in all three dimensions. The fluorescent dye is chosen to fulfill the two-photon absorption criterion for the 1064-nm line of a NdYVO4 laser. The intensity of the fluorescence emission is utilized as a very sensitive position sensor along the optical axis. Two-dimensional images are formed by laterally scanning the trapped latex bead across biological samples while recording the two-photon-induced fluorescences intensity. A scanning probe image of the outer surface of a small neurite from a cultured rat hippocampal neuron is shown, which is hardly visible under differential interference contrast microscopy. The lateral resolution is given by the bead diameter; the axial resolution is 40 nm. Under the experimental conditions the maximal imaging force applied by the probe is below 5 pN.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Microscopía
/
Neuronas
Límite:
Animals
Idioma:
En
Revista:
J Struct Biol
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
1997
Tipo del documento:
Article
País de afiliación:
Alemania