Ultrasensitive Optical Fingerprinting of Biorelevant Molecules by Means of SERS-Mapping on Nanostructured Metasurfaces
Elizaveta Kozhina,
Sergey Bedin,
Alexander Martynov,
Stepan Andreev,
Alexey Piryazev,
Yuri Grigoriev,
Yulia Gorbunova,
Andrey Naumov
Affiliations
Elizaveta Kozhina
Laboratory of Plasmonics, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, 121205 Moscow, Russia
Sergey Bedin
Department of Advanced Photonics and Sensorics, Lebedev Physical Institute RAS, Troitsk Branch, Fizicheskaya Str. 11, 108840 Moscow, Troitsk, Russia
Alexander Martynov
Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskiy Prosp., 31 Building 4, 119071 Moscow, Russia
Stepan Andreev
Laboratory of Physics of Advanced Materials and Nanostructures, Moscow State Pedagogical University, Malaya Pirogovskaya St. 1-1, 119991 Moscow, Russia
Alexey Piryazev
Department of Chemistry, Moscow State University, Leninskie Gory, 1, 119991 Moscow, Russia
Yuri Grigoriev
Laboratory for the Growth of Thin Films and Inorganic Nanostructures Center of Crystallography and Photonics of RAS, Leninskiy Prosp. 59, 119333 Moscow, Russia
Yulia Gorbunova
Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskiy Prosp., 31 Building 4, 119071 Moscow, Russia
Andrey Naumov
Department of Advanced Photonics and Sensorics, Lebedev Physical Institute RAS, Troitsk Branch, Fizicheskaya Str. 11, 108840 Moscow, Troitsk, Russia
The most relevant technique for portable (on-chip) sensors is Surface Enhanced Raman Scattering (SERS). This strategy crashes in the case of large (biorelevant) molecules and nano-objects, whose SERS spectra are irreproducible for “homeopathic” concentrations. We suggested solving this problem by SERS-mapping. We analyzed the distributions of SERS parameters for relatively “small” (malachite green (MG)) and “large” (phthalocyanine, H2Pc*) molecules. While fluctuations of spectra for “small” MG were negligible, noticeable distribution of spectra was observed for “large” H2Pc*. We show that the latter is due to a random arrangement of molecules with respect to “hot spot” areas, which have limited sizes, thus amplifying the lines corresponding to vibrations of different molecule parts. We have developed a method for engineering low-cost SERS substrates optimized for the best enhancement efficiency and a measurement protocol to obtain a reliable Raman spectrum, even for a countable number of large molecules randomly distributed over the substrate.
