Diagnostics & Imaging Week Contributing Editor

ST. LOUIS — The Oak Ridge Conference, organized here by the American Association for Clinical Chemistry (AACC; Washington) and now in its 39th year, provides a forum for presentation of the latest new technologies for clinical diagnostics and for assessment of their impact on the diagnostics market.

This year’s conference, held over the past weekend, covered a range of technologies, including new labeling and detection systems, point-of-care (POC) diagnostics and diagnostics for low-resource settings, emerging technologies for use in molecular diagnostics, including advanced sequencing technologies, and advances in cell diagnostics, including applications in which cells are being used as sensors for rapid diagnostic testing.

Structural changes are occurring in the clinical diagnostics market in addition to technology-driven changes as a result of recent acquisitions, including the acquisition of the laboratory diagnostics business of Bayer AG (Leverkusen, Germany) and Diagnostic Products Corporation (Los Angeles) by Siemens Medical Solutions (Munich, Germany); the pending acquisition of the core laboratory and POC testing business of Abbott Laboratories (Abbott Park, Illinois) by GE Healthcare (Chalfont St. Giles, UK); and the pending acquisition of Biosite (San Diego).

These acquisitions are not likely to have significant impact on the degree of supplier consolidation in the market: the top 10 suppliers will account for 76.5% of the worldwide market, compared to 74.8% prior to the acquisitions (excluding the effect of the Biosite acquisition), but will result in a significant change in the line-up of leading companies in the market.

In particular, the No. 3 and No. 4 players in the market (GE Healthcare and Siemens) have no prior presence in clinical lab and alternate site diagnostics except for their positions in clinical information systems. Their positions in imaging and patient monitoring, where both are leaders, could have a significant impact on the market in the future, however, as both companies begin to implement a strategy integrating in vitro and in vivo diagnostics, and that also is expected to rely on a broader role for informatics.

However, the new market structure could change the basis of competition in the laboratory products market, altering the mix of technologies needed to compete effectively.

Nanodiagnostics, one of the newest technologies in this sector, was discussed at the Oak Ridge Conference by K.K. Jain, of Jain Pharmabiotech (Basel, Switzerland), emphasizing its potential broad impact on testing, both in the central lab and at point-of-care. Jain reviewed recent developments in this sub-sector of nanomedicine, encompassing applications in in vitro diagnostics, in vivo diagnostics and imaging, and therapeutics.

Advantages of nanotechnology in diagnostics include the ability to analyze the function of cellular structures at the nanoscale level, allowing, for example, assessment of receptors and pores in cell membranes; tagging of cells with nanoparticle labels; analysis of chromosomes on a molecular scale including nanodissection and nanoextraction of chromosomal DNA; detection of unique structures on cell surfaces that have diagnostic significance; and integration of diagnostics and therapeutics at the cellular level. Nanotechnology may prove to be an enabling technology for integrating in-vitro and in-vivo diagnostics.

Jain described perfluorocarbon/lipid nanoparticles under development by Kereos (St. Louis) that can be used to label stem cells to allow tracking of cell position using MR imaging after they are injected in the body. Nanoparticle labels are also being evaluated for in vivo imaging of structures not detectable with existing imaging techniques, such as small tumor metastases, small cerebral ischemic lesions that may serve as early indicators of an impending stroke, or intracranial tumors that are not identified with existing contrast agents due to the impediment of the blood-brain barrier. Nanoparticle tags can cross the blood-brain barrier, giving them a unique capability for diagnosis of neurological disorders.

Another example of a unique application for nanotechnology is a Lipoparticle Biosensor under development by Integral Molecular (Philadelphia). Integral is developing a system employing nanoscale lipid particles used as labels in biochemical assays in continuous flow microfluidic analyzers. Such devices, due to their small reagent volume requirements, potential for rapid assay time, high sensitivity and low cost, could revolutionize central lab testing as well as POC diagnostics.

In molecular diagnostics, nanotechnology is enabling single-molecule analysis of nucleic acids, using systems such as the Nanoanalyzer platform from BioNanomatrix (Philadelphia), which being developed for direct analysis of genomic DNA. Likewise, Lumera (Bothell, Washington) is developing protein microarrays based on its NanoCapture technology, with applications in the emerging area of proteomics. Nanotechnology allows fabrication of devices with controlled features on the molecular level, enabling design of devices with characteristics that cannot be created with conventional sensor fabrication technologies.

For example, the spacing of capture probes on a sensor substrate can be precisely controlled using nanotechnology fabrication methods, which provides improved specificity and efficiency of bonding. In addition to enhanced specificity, detection of single bacteria within a period of as little as 20 minutes may prove feasible with nanotechnology-based devices, potentially enabling real-time POC diagnosis of infectious diseases prior to starting therapy.

Oxonica (Mountain View, California) is developing the Nanoplex Rapid and Nanoplex Direct platforms for clinical diagnostics. As discussed at the conference by Michael Natan of Oxonica, the Nanoplex platform employs glass-coated nanoparticles as labels, Surface Enhanced Raman Scattering for detection, a lateral flow assay configuration, and both clinical lab and POC analyzer configurations.

The nanoparticle labels, known as SERS Nanotags, consist of layered nanostructures that provide electromagnetic amplification of the normally weak Raman optical signals to achieve a 10⁶- to 10⁹-fold enhancement in signal intensity, enabling very high detection sensitivity. The nanotags also exhibit very high chemical and optical stability and are insensitive to environmental factors.

The company has developed prototype assays for influenza A and B, as well as Respiratory Synctial Virus with quantitative capability and a 100-fold improvement in detection sensitivity compared to existing lateral flow immunoassay test strips. The company’s new Nanoflex Direct platform, disclosed publicly for the first time at the Oak Ridge Conference, uses magnetic particle separation to eliminate the wash steps normally required for lateral flow assays.

Oxonica has developed a cardiac troponin assay with 40 pg/mL sensitivity that requires no wash steps, no external separation steps, and that provides a single-digit coefficient of variation. A CK-MB assay has also been developed, as well as a multiplex troponin/CK-MB assay. The capability to multiplex up to five analytes in a single assay has been demonstrated.

The company has developed a $15,000 laboratory analyzer, and has placed about 15 systems for user evaluation. A handheld version of the analyzer has also been developed that costs about $3,000, but Natan believes the cost could drop to $1,000 in high volume.

Axela Biosensors (Toronto) has developed the dotLab system which uses Diffractive Optics Technology (DOT) for detection of biomolecules and microorganisms in a label-free format. The system uses a polystyrene test strip with antibodies or other specific binding elements attached to the surface in an ordered array. When target molecules or particles bind to the array, a diffraction grating is formed, allowing real-time detection and quantitation.

A prototype assay for the cardiac marker NT-proBNP has been developed with performance equivalent to that of existing immunoassay systems such as the Elecsys from Roche Diagnostics (Indianapolis), but which can potentially be performed at the point of care with imprecision of 10% or less. An enzymatic amplification technique has also been developed that provides enhanced sensitivity, down to 0.1 pg/mL for BNP. Axela has already commercialized the technology in the research market, with eight dotLab systems installed mainly in North America at about $50,000 each.

The company has licensed a microfluidics technology from Kimberly-Clark (Dallas) that is being used in combination with the DOT detection technology to develop a POC analyzer, dotKey/POC, for CLIA-waived testing. The analyzer consists of a laser and a photodiode detector, a simple configuration that lends itself to POC use. DOT is also a flexible modality that can be used to detect and quantitate particulate targets such as viruses and cells.

Singulex (St. Louis) is developing the Erenna Immunoassay System, which integrates a flow-through immunoassay format with single molecule detection to achieve high-sensitivity quantitative analysis of biochemical markers with a turnaround time of under 30 minutes. Singulex was the first company to demonstrate a cardiac Troponin assay with a sensitivity of 5 pg/mL.

Philippe Goix, PhD, said that one of the company’s goals is to employ its high-sensitivity assays to characterize normal levels of a wide range of disease markers such as troponin and IL-6 which normally are present at concentrations which are too low to be reliably measured with existing immunoassay techniques. The Singulex assays could then be used to screen patients for elevated levels of the target markers, potentially enabling earlier detection of serious diseases as well as tissue damage due to drug toxicity.

Disease screening tests being evaluated by Singulex include tests for early detection of cancer, diagnosis of Alzheimer’s, and early detection of stroke.

Nanosphere (Northbrook, Illiniois) is commercializing a new labeling technology called Biobarcodes, along with its nanosphere particle labeling detection technology, with important applications in clinical diagnostics. Nanosphere versatility enables analysis of both nucleic acids and proteins, and the company has submitted two 510(k) marketing clearance applications for hemostasis assays. Additional assays are under development for measurement of cardiac Troponin I and prostate specific antigen, to be followed by an assay for cystic fibrosis screening.

Biobarcode technology enables very high sensitivity assays to be developed, opening up applications in early detection of conditions such as myocardial infarction, genetic disease, and cancer. In the case of cardiac troponin, Nanosphere is evaluating use of a high-sensitivity assay (with a 0.1 pg/mL detection limit) that may be able to detect cardiac ischemia at an early stage, before the condition progresses to a true myocardial infarction.

According to Greg Shipp of Nanosphere, who discussed the Biobarcodes technology at the conference, the troponin assay has allowed detection of patients who will eventually suffer a myocardial infarction well in advance of the event. That compares to existing troponin assays that do not allow detection of a myocardial infarction up to four-six hours after the event. The new Nanosphere assay is also being studied for applications in detection of cardiotoxicity in patients treated with various drugs, including pediatric patients.