Two-photon microscopy with 113.5-nm resolution

Two-photon microscopy is very useful for imaging living tissues, but the method’s restricted excitation volume typically comes with the trade-offs of lower spatial resolution (especially in the axial direction) and slower imaging than one-photon imaging. Multi-focal multiphoton microscopy–which uses multiple focal spots excitation instead of a single spot–looks promising for overcoming these drawbacks.

Researchers at the Chinese Academy of Science in Shanghai and Sun Yat-sen University in Guangzhou, China have reported their work to improve on the multi-focal technique in the latest issue of the Journal of Microscopy. They produced high-speed two-color two-photon microscopy with improved transverse and axial resolutions by using a 3-D optical lattice made by multi-beam interference and two excitation wavelengths. With 400 and 800 nm excitation they were able to produce 113.5 nm resolution in the transverse and axial directions while imaging faster than is possible with traditional two-photon microscopes.

Research paper: Journal of Microscopy, Two-colour two-photon confocal microscopy with isotropic three-dimensional resolution and parallel excitation, Volume 234 Issue 2, Pages 205 – 210.