It’s become something of a cliché to talk about the “transformative” potential of 3D printing, but there is a solid case to be made that, in healthcare at least, the technology can be a lifesaver in the poorest parts of the world. In the past, PlasticsToday has reported on the $3 plastic stethoscope and a low-cost tuberculosis testing device for developing economies, among other breakthroughs. Now, researchers at the University of Connecticut have 3D-printed an inexpensive, portable high-resolution microscope that is small and robust enough to use in the field or at the bedside. The high-resolution 3D images produced by the instrument could potentially be used to detect diabetes, sickle cell disease, malaria and other diseases, said a news release on the university website.
The microscope, which is based on digital holographic microscopy, doesn't require any special staining or labels and, thus, could increase access to low-cost medical diagnostic testing, according to research team leader Bahram Javidi. "This would be especially beneficial in developing parts of the world, where there is limited access to healthcare and few high-tech diagnostic facilities," said Javidi.
The research is described in the Optical Society (OSA) journal Optics Letters.
The portable instrument produces 3D images at twice the resolution of traditional digital holographic microscopy, which is typically performed on an optical table in a laboratory. In addition to biomedical applications, the microscope could also be useful for research, manufacturing, defense and education.
Because it is entirely made of 3D-printed parts and conventional optical components, it is inexpensive to manufacture and easy to replicate, according to Javidi. "Alternative laser sources and image sensors would further reduce the cost. We estimate a single unit could be reproduced for several hundred dollars. Mass production of the unit would also substantially reduce the cost," added Javidi.
The news release on the university website describes the technology, as follows.
In traditional digital holographic microscopy, a digital camera records a hologram produced from interference between a reference light wave and light coming from the sample. A computer then converts this hologram into a 3D image of the sample. Although this microscopy approach is useful for studying cells without any labels or dyes, it typically requires a complex optical setup and stable environment free of vibrations and temperature fluctuations that can introduce noise in the measurements. For this reason, digital holographic microscopes are generally only found in laboratories.
The researchers were able to boost the resolution of digital holographic microscopy beyond what is possible with uniform illumination by combining it with a super-resolution technique known as structured illumination microscopy. They did this by generating a structured light pattern using a clear compact disc.
"3D printing the microscope allowed us to precisely and permanently align the optical components necessary to provide the resolution improvement while also making the system very compact," said Javidi.
3D-printed microscope has double the resolution of traditional systems
The researchers evaluated the system performance by recording images of a resolution chart and then using an algorithm to reconstruct high-resolution images. This showed that the new microscopy system could resolve features as small as 0.775 microns, double the resolution of traditional systems. Using a light source with shorter wavelengths would improve the resolution even more.
Additional experiments showed that the system was stable enough to analyze fluctuations in biological cells over time, which need to be measured on the scale of a few tens of nanometers. The researchers then demonstrated the applicability of the device for biological imaging by acquiring a high-resolution image of a green algae.
"Our design provides a highly-stable system with high-resolution," said Javidi. "This is very important for examining subcellular structures and dynamics, which can have remarkably small details and fluctuations."
The researchers say that the current system is ready for practical use. They plan to use it for biomedical applications such as cell identification and disease diagnosis and will continue their collaboration with their international partners to investigate disease identification in remote areas with limited healthcare access. They are also working to further enhance the resolution and signal-to-noise ratio of the system without increasing the device's cost.
Image courtesy wladimir1804/Adobe Stock.