NEW YORK ─ Madrid-based startup Mecwins is developing in vitro diagnostic testing technology for use in laboratories and decentralized settings to detect analyte concentrations measured in femtograms per milliliter, or 1,000 times more sensitive than widely available laboratory ELISAs.
The biosensor technology being developed by the company, a spinout of the Spanish National Research Council's Micro and Nanotechnology Institute, is called Avac and uses plasmonic resonance for detection in standard sandwich immunoassays.
Avac enables multiplex testing and has the potential to detect multiple protein, RNA, and DNA biomarkers on a single platform at high levels of sensitivity, said Virginia Cebrián, the company's head of bioscience.
Among the biomarkers the firm has tested using clinical samples are troponin I, a biomarker of myocardial infarction; prostate specific antigen to detect prostate cancer recurrence after a prostatectomy; p24 to detect HIV; and cytokines to detect inflammation, Cebrián added.
According to Mecwins, the instrument is most suitable for use in hospital laboratories because it would enable the testing of hundreds of samples each day. However, the firm recently inked an agreement with San Diego-based Quidel to enable the licensing and codevelopment of its technology for testing in doctors' offices and other decentralized settings.
Apart from combining different protein biomarkers in a single platform, Avac can also combine the detection of proteins and nucleic acids, Cebrián said, adding that such a platform has the potential to detect bacterial or viral RNA, bacterial or viral antigens, and antibodies produced in response to an infectious disease.
"Using one sample, you can see if there is an acute infection or if the patient has a past infection and has antibodies against it," Cebrián said, adding that because the technology is "orders of magnitude more sensitive than current diagnostic tests, it has the potential to detect infection a few days after its onset."
Mecwins said it has validated the technology internally and achieved femtograms per milliliter levels of detection for all of the biomarkers it has tested.
"The possibility to detect the spectrum of light scattered by a single metallic nanoparticle provides a powerful tool for developing advanced biomolecular assays," said Giuseppe Spoto, a professor of chemical sciences at the University of Catania, who is not affiliated with Mecwins. "In this case, plasmonics offers opportunities to establish multiplexed and highly sensitive assays to detect protein biomarkers available in biological fluids at low concentrations," said Spoto, who is developing a testing platform for the plasmonic detection of nucleic acid mutations and protein biomarkers associated with many cancer types.
Because of confidentiality agreements, Mecwins is not disclosing which assays it is prioritizing for the point-of-care instrument it is developing with Quidel, and Quidel did not respond to a request for an interview.
However, Mecwins said that the technology underlying its Avac instrument has the potential to give it an edge over technology used in other testing modalities.
Avac's technology uses digital optical detection of gold nanoparticles that serve as labels that target molecules associated with specific medical conditions. One of the sensor's surfaces is covered with capture antibodies and then incubated with a sample, which can be plasma, serum, blood, or another biofluid, said Andreas Thon, Mecwins' head of software.
Specifically designed chemical steps enable a high density of the capture antibodies and a chosen orientation of the antibodies on the biosensor surface. A chemical blocking step deters the binding of the capture antibodies to molecules that are not of interest.
After the target molecules are captured, gold nanoparticles are added that attach to target molecules and create labels so that the molecules can be detected by imaging.
"These nanoparticles have extraordinary optical properties in comparison with standard fluorescent labels used in diagnostic testing," Mecwins' head of engineering Valerio Pini said. "They present an optical signal that is orders of magnitude higher than a standard fluorescent label, so it allows the digital counting of each individual biomarker with ultrahigh throughput."
At the core of Avac's reader is optical technology based on a darkfield micro-spectrophotometer that can quickly detect all the gold nanoparticles in a sample and digitally count each target molecule, Mecwins said.
The use of gold nanoparticles also enables multiplexing. A change to the size or shape of a nanoparticle enables it to emit a different color and amount of brightness. That allows Mecwins to associate specific sizes or shapes with specific target molecules, Pini said, adding that the instrument's accuracy and sensitivity is augmented by "a very specific substrate that we have developed in the last few years that amplifies the signals coming from nanoparticles."
Software also plays a role in the instrument's sensitivity. Avac is unlike fluorescence detectors, which have the challenge of detecting a change in the aggregate amount of light coming from a surface in response to the presence of a target molecule, Pini said. Instead, Avac detects each individual gold nanoparticle as it binds to a target molecule in a sample, and when substances such as dust and other undesired particles are present in the sample, Avac's software can decide what is useful to measure and what is not.
While Mecwins develops the Avac instrument for laboratory use, it is looking to Quidel to guide the development of its technology for the point of care.
Under the terms of the agreement with Quidel, the Spanish firm is contributing expertise in the development of its biosensor technology, and Quidel is contributing cartridge and immunoassay design know-how. Longer term, Quidel will also contribute marketing and product distribution expertise, said Beatriz González, Mecwins' head of financing. However, the deal is not exclusive and Mecwins will seek additional worldwide distribution agreements for all of its products, she said, adding that it has plans to establish an internal team for marketing and sales.
González noted that the firm has agreements in China, India, Brazil, and the US for the distribution of a separate research-use-only instrument, called Scala, short for scanning laser analyzer. Scala uses nanomechanical cantilever-based sensing for biochemical detection and biomarker discovery. The firm has been selling the instrument to research centers, including academic institutions, since 2010, and intends to establish similar agreements for the marketing of Avac, González said.
Avac combines the first letters of the first names of the Mecwins employees involved in its development. In July, Mecwins announced it raised €4 million (then $4.7 million) in funding from current and new investors to support the development of diagnostic testing prototypes based on the technology.
The company also entered an agreement recently to partner with Madrid-based Ramón y Cajal Institute for Health Research, or IRYCIS, to clinically validate the technology to detect hematology and autoimmune diseases in pilot studies.
Going forward, the production of "robust and homogeneous functionalized nanoparticles that provide distinct spectra for the different biomarkers to be detected" could prove challenging for Mecwins' developers, Spoto said, noting that for a point-of-care instrument, the developers will need a platform that enables "minimal pre-analytical processing of the patient’s sample."
The firm is deciding on a medical indication for its first assay. It aims to first launch an Avac laboratory instrument and assays for research use, and later, pending regulatory approvals, for in vitro diagnostic testing. It will take at least three years to develop and commercialize its first in vitro diagnostic test, the firm said.
González added that the pursuit of European Union regulatory approvals and US Food and Drug Administration clearances in collaboration with IVD industry partners are part of its future plans.
Mecwins declined to be specific about the anticipated price of its instrument, but said it will be in the tens of thousands, rather than hundreds of thousands, of dollars.