## 1 Introduction  
Detection of ultra-low proteins concentration in solution using novel physical effects like plasmonics, surface-enhanced Raman spectroscopy, and photonic waveguide-based sensors are promising techniques for novel medical diagnostics [1; 2; 3; 4; 5; 6; 7]. In particular, a low myoglobin concentration is a relevant marker of myocardial infarction in human blood plasma [8; 9; 10]. It is well known that the amplified SERS response of organic molecules could be obtained by depositing those on specially designed silver, gold or copper thin film substrates [11; 12; 13; 14; 15], as well as using silver or gold colloidal nanoparticles in solution [16; 17; 18; 19]. One of the most critical issues of any SERS-based analysis is a procedure of protein probe preparation both for planar thin film SERS substrates and colloidal techniques. Conventional research on SERS-based sensors often depends on nanoparticle aggregation, whereas the non-reproducible nanoparticle aggregation gives rise to poor repeatability in the Raman signal. The simplest method of probe preparation is the drying of analyte solution drop on a SERS substrate in air under normal conditions. Compared to the metal nanoparticles solution used for protein deposition, the drying method is more convenient and faster because it does not require any precise control of chemisorption processes using a large number of auxiliary reagents. Moreover, the developed method provides the minimal amount of analyte required for analysis (about several micro litters) and minimizes sample preparation time, compared to various methods of surface modification using antibodies, which take several hours and require a number of reagents. It is well known, that both shape (and size) of dried probe on the SERS substrate surface and near-surface light rays trajectories have to be taken into account. By using planar SERS-active substrates, it is possible to utilize such a simple and quick sample preparation methods like probe drying, which, on the one hand, ensures the minimum area of sediment formation, on the other hand, provides sediment-surface conformation, which gives additional Raman signal enhancement. Various metal films and fabrication techniques are used for this purpose: physical vacuum deposition (PVD) [20; 21], electrochemical deposition from the solution [22; 23; 24], deposition from a colloidal solution of nanoparticles [25; 26; 27; 28], electron-beam lithography [29; 30], plasma-chemical lithography [31]. All the recently used metal thin films and surfaces for SERS-based sensorics usually based on already known general principles of creating surfaces for the successful registration of the giant Raman spectra [32]. First of all, SERS structures/surfaces must have the morphology or topology features, which satisfy the conditions of local field enhancement in the selected range of Raman spectra registration wavelength [32; 33; 34; 35]. Many recent researchers demonstrate registration of Raman spectra of proteins [19; 36; 37; 38] by means of SERS substrates with patterned metal films or well-structured morphology. It is worth noting that a metal film surface roughness could be a very important factor as it corresponds to forming and optimal adsorption of analyte near so called \"hot spots\". When precipitating the analyzed substance from a solution, the scale of a substrate surface relief inhomogeneities affects dramatically on the way of analyte particles crystallization, sedimentation in the process of near-surface microcirculation and precipitate formation during analyte drops drying [39; 40]. Unfortunately, there are still no simulation techniques, which provide an opportunity to predict substrates surface morphology corresponding to thin films deposition recipe parameters. From the other hand, there is a possibility to form almost any SERS-active substrates nanoscale morphology and topology using well-known e-beam lithography and dry etching processes, but they are still too expensive for mass production.