Andreas Knaack, MSc
Director of Instrument Design & Development, Invetech
Point-of-care industry takes a page from drug discovery.
Many traditional tests for diseases, like cancer, are too complex, too expensive, or too slow to be useful in clinics. This results in a lag time between testing, diagnosis, and treatment. Therefore, there exists an impetus to develop point-of-care diagnostic tests (POCT). In many cases, companies are co-opting technologies from the drug discovery toolkit and using them in point-of-care devices.
Early POCTs were typically performed at the bedside, for example urine testing. However, new developments in analytical systems have enabled tests to be carried out
simply and quickly without sending samples to central laboratories. Point-of-care will deliver diagnostic systems directly to the patient and doctor. POCTs can potentially reduce diagnosis times, and improve the effectiveness of treatments while achieving the specificity and sensitivity normally associated with the currently standard tests.
Typical non-POCT analyses involve a lengthy process, starting with sample preparation, chemical, biochemical, or molecular analysis and ending with data collection and interpretation. Any practical point-of-care application would require most of these operations to be integrated into a single system.
The Lab-on-a-Chip market has grown exponentially over the past few years, especially in relation to drug discovery applications. Lab-on-a-Chip is useful for applications such as genomics and proteomics, all performed on a device the size of a credit card. It is a generic term for a system or device designed to perform one or more chemical/biochemical processes leading to a controlled reaction or analysis. The aim of Lab-on-a-Chip is to perform complicated analyses with a minimum of sample and rea-gents. Analysis involves any liquid sample. Miniaturization also permits more tests per sample (volume), and improves production where reagent costs are high.
The early, rapid, and sensitive detection of the metabolic or disease state is a vital goal for emergency point-of-care or clinical diagnostics. Lab-on-a-Chip devices are particularly effective for processing or testing thousands of samples under nearly identical conditions in an automated environment. This means that it lends itself particularly well to POCT, where small samples need to be analyzed using small (preferably handheld) devices, quickly.
Microarrays and nanotechnology
Microarrays have also made the transition from the drug discovery market to point-of-care application. Researchers typically apply microarrays to genotyping, mutation screening, gene expression, and protein-interaction studies.
Typically microarrays provide ever more information per experiment. In the drug discovery arena, researchers use microarrays to perform large-scale studies in larger populations than ever before, providing a more comprehensive view of the human genetic variations that cause common diseases.
In point-of-care applications, microarrays are increasingly used for both diagnostic and predictive purposes. More and more, microarray-based devices can perform near-patient viral DNA testing.
For example, researchers have recently developed a molecular test that can identify sub-types of diseases, whereas the more traditional immunodiagnostic approach can only detect the presence of the disease. In the case of malaria, for example, the particular sub-type of four can be identified using microarray analysis, rather than merely determining whether the subject has contracted malaria.
Although a reduction to the micro-meter scale will not usually affect the nature of molecular reactions, it may enable dramatic increases in throughput. This has led a number of companies to deploy the benefits of nanotechnologies for both drug discovery and point-of-care products.
The main application of nanotechnology in POCT will increasingly be in the area of surface treatment of consumables to enable the use of low reagent and sample volumes.
Other miniaturized technologies
In recent years, companies have been creating other miniaturized solutions for use in both drug discovery and point-of-care products. These devices feature components such as fluorescence and electrochemical sensors, but all aim for flexibility with high sensitivity, high specificity, a wide dynamic range, and rapid time-to-result.
Recent developments have seen sensors integrated into microchips for immunoassay analysis. The ultimate goal is that a healthcare professional would need to take no more than a drop of blood from the patient while in the consulting room, deposit it on the microchip, and push a button to trigger the fully automated analysis. Combining the advantages of disposable micro-analytical systems with electrochemical or optical detection has opened up new areas for biosensors in POCT.
Developing POC devices
Many of the advances in drug discovery and POC technology are due, in large part, to formal and informal collaborations between biotechnology, pharmaceutical, and instrument-development companies. Collaborations between instrument-development specialists, and manufacturers helps bring about solutions more quickly than usual in such a complex arena. Point-of-care technology development relies on a number of disciplines, including optical design, development of automated manufacturing solutions, molding, materials science, and chemistry to name but a few. It is rare that biotechnology and pharmaceutical companies have specialists in all of these skills in-house. There is, therefore, an increasing trend for manufacturers to outsource device development to specialist companies.
Companies looking to develop successful POC or drug discovery devices are faced with challenges that can often more easily be addressed by specialist instrument-development service providers. Issues such as selecting and implementing features that will satisfy the end-user’s needs cost-effectively, developing the technology into a viable and functioning product, and ensuring that appropriate market applications have been developed, are often easier for independent companies.
Diagnosis at the point of care offers many advantages over sending samples to central laboratories, which, in turn, reduces the cost of healthcare. Growth in point-of-care diagnostics has been made possible through advances in technology, automation, and IT.
Point-of-care technology is only in its relative infancy, but it looks set to explode because of advances in miniaturized technologies that provide better sample data in terms of sensitivity and specificity.
This article was published in Drug Discovery & Development magazine: Vol. 10, No. 4, April, 2007, pp. 36-37.
Filed Under: Drug Discovery