1. Institute of Physics, Saratov State University, Astrakhanskaya Street 83, 410012 Saratov, Russia
2. Ioffe Institute, Politekhnicheskaya Street 26, 194021 Saint Petersburg, Russia
3. Department of Physics, Yuri Gagarin State Technical University of Saratov, Polytechnicheskaya Street 77, 410054 Saratov, Russia
4. Laboratory of Biomedical Nanotechnology, I.M. Sechenov First Moscow State Medical University, Trubetskaya Street 8-2, 119991 Moscow, Russia