Fluorescent Nanomaterials to Enable Biomedical Selfies
If you’re diabetic or think you might be pregnant, affordable technologies for determining your health status can be found at grocery stores and pharmacies. For most other conditions, checking your health status requires a trip to the doctor and another trip to a clinical lab to have a blood or urine test done.
What if these types of medical tests could be as simple as taking a selfie with your smartphone? Researchers in the Department of Chemistry at the University of British Columbia are working to make this concept a reality.
Professor Russ Algar, a Canada Research Chair in Biochemical Sensing and Michael Smith Foundation for Health Research Scholar, and his team of researchers work extensively with a type of material called a “quantum dot.” These materials are semiconductor nanocrystals between 4–10 nm in size. It is because of their nanoscale size that quantum dots exhibit very bright fluorescence with a combination of properties that is superior to virtually all other known fluorescent materials.
It turns out that the fluorescence from a quantum dot is a nearly perfect match to your smartphone camera. A smartphone camera doesn’t take true colour images, but rather takes images in red, green, and blue. These three colours are then combined to create
an image that resembles what is seen by eye. “Quantum dots can be synthesized to have fluorescence with a very pure colour.” says Michael Tran, a graduate student working with Algar. “The combination of colour purity and excellent brightness makes it possible to efficiently image quantum dot fluorescence with a smartphone.” Standard molecular materials, such as fluorescent dyes and proteins, don’t have the brightness or color purity to be practically imaged with a smartphone.
To create a biomedical test, or assay, quantum dots are decorated with antibodies, peptides, DNA sequences, or other biological molecules that can interact with the biomarkers of a disease or condition. With some clever design, the fluorescence intensity of the quantum dots will indicate how much of the biomarker is present in a patient sample, and thus report on health status. The job of the smartphone is to image the quantum dot fluorescence wherever and whenever, without the need for specialized laboratory equipment or training.
“A smartphone represents a portable, mass-produced, and ubiquitous device,” explains Algar. “It’s a model technology that could be used for blood and urine tests at-home, while waiting at the doctor’s office, at the bedside in a hospital, or in rural or remote communities, all with little or no barrier to uptake by patients and health professionals.” Although Algar stresses that research and development is still in the early stages, important milestones have been achieved. A smartphone assay with quantum dots has been shown to reproduce results obtained with sophisticated laboratory equipment, a smartphone has been used to measure quantum dot fluorescence in blood and serum samples, and a 3D-printed peripheral accessory for a popular model of smartphone has been developed for these assays. Algar and his group have now partnered with industry to further develop their technology, and he notes that exciting work is being done all around the world to develop smartphone-based biomedical technologies.
“A longstanding goal in analytical chemistry is to shrink a lab down to the size of hand-held chip, but a challenge has been making the measurement technology equally portable,” concludes Algar. “A smartphone, enabled by the special properties of nanomaterials, may be the answer. Lab-on-a-chip-on-a-phone technology will enhance the efficiency and efficacy of health care, and make implementation of personalized medicine much more feasible.”