Open Source 3D-printed focussing mechanism for cellphone-based cellular microscopy.

Area of Science:

• Biomedical Engineering
• Optical Engineering
• Materials Science

Background:

• Cellphones with cameras offer a platform for portable, low-cost microscopy.
• Improving access to microscopes in low-resource settings is crucial for education and healthcare.
• Reproducible focus control is essential for reliable imaging in field microscopy applications.

Purpose of the Study:

• To develop and evaluate a 3D-printed focusing mechanism for ball lens-based cellphone microscopes.
• To quantify the focus stability of the developed mechanism for field microscopy.
• To enhance the utility and reproducibility of low-cost, portable microscopes.

Main Methods:

• A 3D-printed rack and pinion focusing mechanism was designed and integrated with a ball lens microscope.
• Focus stability was quantified using an edge-based contrast measure, similar to autofocus cameras.
• The mechanism was tested with thin blood smears infected with Plasmodium and onion skin cells.

Main Results:

• The developed 3D-printed focusing mechanism achieved focus stability in the micrometer range.
• The mechanism enabled stable image acquisition for cellphone microscopy of biological samples.
• The device demonstrated potential for reproducible imaging in educational and clinical settings.

Conclusions:

• The 3D-printed focusing mechanism enhances the reliability of low-cost, field-portable microscopes.
• This open-source development contributes to improved access to microscopy in underserved areas.
• The technology supports the advancement of affordable and accurate field microscopy solutions.