A team of researchers from the Polytechnic University of València (València, Spain), the Center for Cooperative Research in Biomaterials (CIC biomaGUNE; San Sebastián, Spain), and the Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN; Zaragoza, Spain) has developed a technique that involves surface-enhanced Raman spectroscopy (SERS) to detect cocaine and mycoplasma at very low concentrations. The development could serve as an alternative for use in laboratories and is potentially more competitive than existing analysis methods.
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The method combines the use of gated mesoporous silica nanoparticles and SERS a signal amplification system that uses gold nanoparticles to detect very low concentrations of the substances being analyzed. In the lab, it allowed the research team to reach nanomolar detection levels for cocaine and 30 copies of genomic DNA/μL in the case of mycoplasma.
Mycoplasma refers to a genome of prokaryotic microorganisms that have been described as parasites of various animals and plants, according to the researchers. In addition, they say, their characteristic lack of a cell wall makes them resist many common antibiotics, so they are often present in research laboratories as cell-culture contaminants. So, detection of these microorganisms is of general interest in the biomedical and life sciences.
The new detection system is based on the release of a dye that is easily identifiable by SERS from inside the silica nanoparticles, provided the substance being detected is present," explains Ramón Martínez Máñez, director of the Inter-university Research Institute for Molecular Recognition and Technological Development and scientific director of CIBER-BBN. "In the presence of mycoplasma or cocaine, the pores of the nanoparticles unblock, letting in the dye that interacts with gold nanotriangle. It is this interaction that is detected by SERS spectroscopy. The concentration of the substance being detected is proportional to the signal detected," he says.
Luis M. Liz-Marzán of the Basque Centre for Cooperative Research in Biomaterials adds that the results the research team obtained so far are very positive, and point to the possibility of this method being used in the detection of other pathogens.
Full details of the work appear in Chemistry-A European Journal; for more information, please visit http://dx.doi.org/10.1002/chem.201602457.