Quantum dots (QDs) are the biggest disruptor so far on the imaging landscape. From semiconductor inspection to security cameras, industries reliant on high performance imaging and sensing are realising the benefits of tapping into short wave infrared (SWIR) wavelengths using INFIQ® infrared QD technology. 

SWIR detectors, which capture hidden data to ‘see’ beyond the visible, are already being used for inspection and monitoring applications. However, as nanotechnology advances, we are seeing more and more interest in how QDs can expand the field of nanomedicine, heralding a revolution for patient treatment and diagnosis as we know it. 

In medical diagnosis, speed and accuracy are key to success. The earlier an illness can be detected, the sooner treatment can start, putting the patient on the road to recovery. 

Thanks to the unique properties of SWIR light, sensors equipped with industry leading infrared QD technology can make diagnoses safer, more accurate, and most importantly, faster. SWIR light can travel further through scattering mediums than near infrared (NIR) or visible light, meaning detectors can ‘see’ further through otherwise solid objects – enabling doctors to quickly spot hidden conditions in the body. 

SWIR technology is already employed in the medical sector for certain specialist applications, such as optical coherence tomography. This process is well-established for capturing high-resolution images of the retina, but thanks to the properties of SWIR light, it is enabling images to be captured deeper through the retina, reaching the blood vessel layer, to detect otherwise hidden eye conditions. 

But as QDs enhance the availability of SWIR imaging and sensing, with lower cost than existing solutions and smaller pixel pitch enabling higher resolution while keeping the same optical format, we will begin to see further medical applications develop.   

Modern SWIR imagers are based on Indium-Gallium-Arsenide and have a maximum resolution of 1.3 megapixels as further improvements are difficult to achieve. InGaAs chips are also costly and challenging to produce at scale, with only a few or a few dozen qualified InGaAs chips able to be produced per substrate at most. Due to process limitations, InGaAs pixel sizes are difficult to reduce, so higher resolution means larger chip sizes, much lower yields, and much higher prices. 

In contrast, QD based imagers can be manufactured on 8” or 12” wafers, and the pixel size can be reduced to sub 2um level. SWIR imagers with higher resolution and more affordable costs are therefore possible. 

The ability to detect many medical conditions relies on searching for ‘biomarkers’ – biological molecules found in the body that indicate certain medical states. For example, cancer cells give off specific biomarkers that in turn have their own unique spectral signatures. Historically, invasive procedures utilising fluorescent dyes or biopsies have been among the most common methods for early biomarker detection. However, these methods may cause the patient great discomfort. 

SWIR imagers, utilising QDs, change the game for biomarker detection. QDs enable medical sensors to tap into SWIR wavelengths at a cost-effective price point, enhancing their resolution and sensitivity. This light can penetrate deeper into the human body than other wavelengths to identify changes in a patient’s veins, teeth, or deep tissue that would otherwise be difficult to detect.  

For example, QD-equipped SWIR technology means doctors can more easily identify the unique spectroscopic signatures given off by cancerous cells, helping them detect tiny abnormalities with even greater precision. SWIR light can also be used to monitor biomarkers from substances like alcohol or glucose in a patient’s sweat or skin, making it far simpler to detect abnormalities without the need for blood tests. 

The benefit of this technology is in providing medical specialists with a non-intrusive method for monitoring changes in a patient’s condition. As a result, they can conduct non-invasive imaging that does not harm the surrounding tissue, enabling repeat examination and reducing patient discomfort. 

Not only does SWIR imaging offer higher performance than other methods, unlike ionising radiation sources such as x-rays, but exposure to SWIR light is also not dangerous. In fact, in some settings, QDs could find use as x-ray scintillators: in mammogram screenings or similar procedures, use of QDs could let doctors administer lower x-ray doses, leading to vastly reduced costs compared with using larger area detectors. 

Besides these emerging applications, QDs even have potential applications for drug delivery, directly targeting areas of the body and overcoming existing challenges with only a small proportion of drugs reaching the desired area.  

As lead-free infrared QD technology advances, the range of applications that QDs can be used for will significantly expand, including in the medical sector. Providing a safer, non-toxic tool for high-performance SWIR sensing, INFIQ® technology is bringing world-changing functionality into all our lives – and helping to keep those lives as healthy as possible. 

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