This is a challenge for scientists with the goal of democratizing health care for economically disadvantaged people around the world.
My colleagues and I have developed a new method for examining biological cells that is small enough to fit into a smartphone lens.
While we’ve only tested it in the lab so far, we look forward to it in the future Nanotechnology Only using a mobile device can enable disease detection in real-world medical settings. We hope that our work will eventually help save millions of lives.
How to investigate a biological cell
Being able to examine biological cells with an optical microscope is a fundamental part of medical diagnosis.
This is because certain changes in cells that can be observed under a microscope are often indicative of disease. In the case of malaria, for example, the gold-standard method of diagnosis involves the use of microscope images to identify specific changes in a patient’s red blood cells.
But biological cells are good at hiding. Many of their internal characteristics are practically transparent and almost invisible to conventional microscopes. To make these features visible, we need to apply the tricks.
One way is to introduce some kind of chemical staining, which adds contrast to the transparent properties of cells.
Other approaches use a process called “phase imaging”. Phase imaging exploits the fact that light, which passes through a cell, contains information about the transparent parts of the cell – and this information makes it visible to the human eye.
Traditional phase-imaging methods rely on a wide range of components, such as prisms and intervention setups, which can cost thousands of dollars. Also, expensive and heavy equipment may not be readily available in remote areas and economically disadvantaged countries.
Enter nanotechnology
A major scientific effort is currently underway to take advantage of nanotechnology to replace traditional large optical components.
This is being done by making nanometer-thick devices with the potential for mass production at low cost. These devices could be integrated into mobile devices such as smartphone cameras in the future.
In the specific case of phase imaging, scientists have previously been able to develop only systems that:
Relies on time-consuming computational post-processing, which complicates the process and does not allow real-time imaging
Still use mechanically rotated or rotating parts. Due to the space requirements of these parts, they are completely incompatible with flat optical components and ultra-compact integration.
We’ve developed a device that can do instant phase-imaging without these limitations. Our solution is only a few hundred nanometers thick, and can be integrated into the camera lens, in the form of a flat film on top of the lens.
How we did it
We have embedded a nanostructure in a very thin film (thickness less than 200 nanometers) that enables phase imaging using an effect sometimes called “”.Optical spin-orbit coupling”
The principle of operation is simple. A transparent substance, such as a biological cell, is placed on top of the device. Light emanates from the cell and the previously invisible structure of the cell appears on the other side.
In our recent publication in ACS Photonics, we detail how we successfully demonstrated the use of this method in a laboratory environment with artificially generated transparent objects. Objects were only a few micrometers in size, and therefore comparable to biological cells.
Because this method enables phase imaging, but does not deal with the expansion of small objects such as cells, it still needs a wide lens to provide magnification. However, we are confident that in the future our device may be integrated with the flat lens, which emerges from other advances in nanotechnology.
Where can he lead us?
One challenge with the current device prototype is the fabrication cost of around A $ 1,000. We have used many expensive nanofabrication methods which are also used for fabrication of computer chips.
“Taking advantage of the scale economy associated with chip production, we believe we will be able to achieve faster and lower production of this device in the next few years,” he said.
So far we’ve only done this in the lab. The technology available in medical mobile devices will require collaboration with engineers and medical scientists who specialize in the development of such devices.
Our long-term vision for technology is to allow mobile devices to investigate biological samples in a way that has not yet been possible.
In addition to allowing remote medical diagnostics, it can also provide in-house diagnostics, in which the patient can obtain his or her own sample through a saliva, or blood, pinprick, and send the image to a laboratory anywhere in the world.
