Fully 3D-printed endomicroscopic objective for two-photon, multi-wavelength excitation microscopy

Area of Science:

• Optics and Photonics
• Biomedical Engineering
• Materials Science

Background:

• Endomicroscopy requires compact, high-performance imaging objectives.
• Traditional objectives face challenges in miniaturization and assembly for in vivo applications.
• Advanced fabrication techniques like 3D printing offer potential for novel optical designs.

Purpose of the Study:

• To design and fabricate a fully 3D-printed, broadband endomicroscopic objective lens.
• To optimize the objective for near-infrared two-photon fluorescence imaging.
• To demonstrate its performance and feasibility for in situ tissue imaging.

Main Methods:

• Utilized multi-material two-photon polymerization (2PP) for monolithic 3D printing.
• Designed a three-element refractive objective with a compact, alignment-free architecture.
• Integrated a self-aligning housing to minimize assembly errors and ensure optical precision.

Main Results:

• Achieved a numerical aperture of 0.6 in water immersion with a 200 µm field of view.
• Maintained near diffraction-limited performance across the 720-950 nm excitation band.
• Validated optical performance with resolution targets, pollen imaging, and mouse liver autofluorescence.

Conclusions:

• Fully 3D-printed broadband objectives are feasible for compact, high-performance endomicroscopy.
• The developed objective demonstrates potential for integrated biomedical optics and in situ tissue imaging.
• This fabrication approach enables miniaturized, alignment-free optical systems for advanced biomedical applications.