Delivering diagnostics

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Delta Optical Thin Film’s high-performance fluorescence filters diced for PoC applications (credit:Delta Optical Thin Film)

Gemma Church explains how Delta Optical Thin Film is helping to deliver miniaturised and accurate point of care diagnostics with its optical filters

Fast and accurate diagnostics have always been of paramount importance to the medical community. But the recent pandemic accelerated the development and requirement for diagnostics, impacting both the Point of Care (PoC) device sector and wider optics industry.

The benefits of PoC devices are clear across a range of medical applications. They can replace many labour-intensive and lengthy diagnostics processes where sample collection, sample processing, sample testing, and the collection and analysis of results can take days to complete and require a laboratory setting. Instead, medical staff can use PoC devices to accurately achieve real-time, lab-quality diagnostic results within hours or even minutes. 

There are already many PoC devices available on the market, from blood glucose monitors to more sophisticated molecular analysis instruments. These PoC devices are not just used by medical professionals either, and are increasingly helping patients stay in their homes to monitor their health and administer the appropriate treatments, where possible.

Poul Svensgaard, CEO of Delta Optical Thin Film, explained: 'We are seeing an increase in Point of Care solutions as the medical industry demands faster and more specific diagnostics to improve patient care. There are many reasons behind this trend. 

‘First, there is a need to streamline the diagnostics process and help clinicians prescribe the right treatments. This is important to help avoid bacterial resistance to antibiotics, for example, because patients are now given a fast and accurate diagnosis instead of being administered wide-spectrum antibiotics. Using PoC devices, medical professionals can target the right treatment, based on the individual patient’s actual situation.’

Svensgaard added: 'Second, there is a need for diagnostics in developing countries where laboratory testing facilities may be few and far between. 

‘Finally, there is an increased need for home testing to monitor and manage chronic diseases. This all eases the pressure on clinicians and caregivers, while helping patients receive the best treatments.’

This increase in demand for PoC devices has had an impact on the instrumentation space. There is now a requirement for smaller, faster and lower-cost instruments. These devices must also work in various environments, such as a doctor’s office, private homes and in countries or regions with no or limited access to laboratories.

As a result, today’s PoC medical devices require portable, small and robust instrumentation. What’s more, most of the potential applications of PoC technology require a detection sensitivity at least equivalent to existing methods. So, the optics in such devices also must match the performance and accuracy of those found in larger systems, at the very least. 

Miniaturise matters

A key challenge for today’s PoC devices is to reduce the size of all optics without compromising the optical output. 

This has had a knock-on effect for optical film manufacturers. Svensgaard explained: ‘Most optically based diagnostic instruments are based on three core elements - excitation filters, emission filters and dichroic beam splitters. As PoC devices continue to miniaturise, there is no room for dichroic beam splitters and the optics used in these devices need to adapt.’

Most PoC devices are based on LED light sources and silicon-based photodiodes. Thus, the optical filters for these types of instruments require very steep bandpass optical filters with high out-of-band blocking to compensate for the lack of dichroic beam splitters.

Delta Optical Thin Film is often involved in optimising the optical systems used in PoC devices. Svensgaard said: ‘We tend to focus on improving the quality of the instrument, working together with our customers.’

‘Our background as an OEM supplier of high-quality, custom optical filter sets for fluorescence microscopy gives the right background as a supplier of optical filters used in PoC instruments. Many times, our high-performance fluorescence filters have been the starting point for many beneficial collaborations,\'92 Svensgaard added.’

Recently, Delta Optical Thin Film worked in collaboration with Qlife Holding for the company’s Egoo hand-held device for molecular virus testing. This can provide a SARS-CoV-2 PCR test result in 30 minutes directly to a digital device and also measure biomarkers from a single drop of blood. 

This is just one example of Delta Optical Thin Film’s work in this area. Svensgaard explained: ‘PoC diagnostics suppliers tend to need microfluidics technology, medical expertise and optical expertise. These suppliers need close and efficient partnerships between these very different companies.’

‘Delta Optical Thin Film has worked as a trusted partner with such companies for many years, and we have been involved in optimising the optical systems for such devices, thereby improving the quality and reducing the complexity of the instrument together with our customers,’ Svensgaard added.

Delta Optical Thin Film’s custom optical filters are used in a range of clinical applications in the biomedical, biotech and drug discovery markets, with its optical filters engineered for the next generation of “PoC” instruments.’

In the company’s latest whitepaper, Delta Optical Thin Film explains how it is meeting the requirements of today’s medical instrumentation market for smaller PoC devices by creating miniaturised optical filters, and how its state-of-the-art manufacturing techniques can provide high-throughputs at low cost for these filters.

The optical filters are highly advanced, with designs modified to meet the demands of PoC instruments. They contain a tremendous amount of layers, according to Svensgaard, more than 330 layers on each side of a glass substrate in some cases. ‘The interesting thing is we’ve been able to manufacture these filters on machines with large fab sizes, increasing the throughput and batch sizes of our filter production while keeping the costs down for our customers, especially compared to techniques that use ion beam sputtering coating machines.’

When it comes to miniaturisation, the company’s filters can scale down to mm2. They can also be delivered diced on UV-cured tape or drilled to achieve the final size.

The company’s manufacturing capabilities incorporate a high degree of automation across handling, coating and spectral control processes. The optical filter packaging, for example, is suitable for automatic picking in a production environment.

This all streamlines and expedites the manufacturing process while providing OEMs with the best filters for the increasingly competitive PoC instrument market. Svensgaard concluded: ‘Our manufacturing processes create high-quality and miniaturised optical filters at reduced cost and high yield. We work hard to keep pace with the many markets we serve and meet the requirements of every customer.’

For more information on this topic please click here to download a White Paper. 

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