Finding new signal systems based on nanoparticles
In the frame of the project, we are working in finding new signal systems based on nanoparticles for improving the sensitivity of molecular tests. The amplification of the genetic material is combined with the immunomagnetic separation during sampling for a further increase of the sensitivity. Therefore, the TB bacilli are pre-concentrated from the biological fluids by immunomagnetic separation based on tailored magnetic nanoparticles, incorporated on the sampling tube. Following the lysis of the captured bacteria, the released DNA is simultaneously amplified and labeled by an end-point double-tagging PCR in the portable thermocycler.
We are developing a portable molecular test for the detection of TB in sputum and their resistance to the main anti-TB drugs, relying on a hand-held thermocycler operated by solar cells to perform double-tagging end-point PCR in combination with a nucleic acid lateral flow test. This method can generate billions of tagged DNA copies from a single target molecule within a few hours, increasing the sensitivity of the test, that can be rapidity detect with immunochromatography platform based on carbon nanoparticles to provide the diagnosis of infection with the naked eye, in low resource settings.
The pandemic highlighted that both PCR and LFA are the dominant formats for a massive laboratory testing and point-of-need diagnosis. In this proposal, we will put PCR at point-of-need, by combining both technologies in a prototype, to solve the complexities of diagnosing TB as a first model. The test is considered an in-vitro diagnostic product which is a point-of-care rapid test based on a lateral-flow platform for the rapid detection of a TB in a total time of just 50 minutes. The product is mainly composed by two components: 1) portable hand-held thermocycler operated by solar cells, in which the sample is amplified for 45 min by cycling the temperature at fixed condition (no programming is allowed for the final used). 2) Fungible or readout platform, which allows visual detection readout in less than 5 minutes of the presence of the bacteria, as is the case of TB. The output of the device is binary YES/NOS response.
The device is rapid and inexpensive, requiring minimal handling, and can easily be introduced into the general practitioner’s armory for ambulatory screening of infection. Furthermore, although the first application that is envisaged for is targeted to TB infection, this approach will be also transferable to the diagnosis at community and primary-care level of other infectious diseases related with global health, increasing thus its valorization.