MEMS-based handheld confocal microscope for in-vivo skin imaging

Area of Science:

• Biomedical optics
• Microscopy
• Medical imaging

Background:

• Confocal microscopy is crucial for high-resolution biological imaging.
• Existing handheld microscopes often lack the resolution and speed for detailed skin analysis.
• Microelectromechanical systems (MEMS) offer potential for miniaturized scanning solutions.

Purpose of the Study:

• To develop and characterize a handheld laser scanning confocal microscope for in vivo skin imaging.
• To achieve high resolution and frame rates for detailed epidermal and dermal visualization.
• To demonstrate the capability for imaging dynamic processes like capillary blood flow.

Main Methods:

• A handheld confocal microscope design incorporating an electromagnetic MEMS bi-axial micromirror for beam scanning.
• Utilized commercial objective lenses with an optional hemisphere front lens for variable numerical aperture (NA=0.35-1.1).
• Evaluated system performance using an 830 nm laser, measuring axial and lateral resolution.

Main Results:

• Achieved 800 x 600 (SVGA) resolution at 56 frames per second.
• Measured axial response of 1.14 µm (FWHM) and lateral edge response of 0.39 µm (10%-90%) at NA=1.1.
• Acquired high-resolution images of epidermal and dermal structures, including capillary blood flow.

Conclusions:

• The developed handheld confocal microscope represents a significant advancement in tissue imaging technology.
• It offers the highest resolution and frame rate for tissue imaging using a MEMS bi-axial scan mirror to date.
• The system is capable of detailed in vivo skin imaging, with potential applications in dermatology and biomedical research.