These methods are rapid, simple, and inexpensive but produce random orientation of bioreceptors (attributable to multiple functional organizations on the protein), which could decrease the conformational flexibility, hindering the bioreceptors/analytes interaction and thus lowering the sensor sensitivity. medical markers (microRNA) and for pathogen detection. Finally, examples of pathogen detection by immunosensing were also analyzed. A parallel assessment with the research methods was duly made, indicating the c-FMS inhibitor progress brought about by SPR systems in medical routine analysis. Keywords: Surface plasmon resonance (SPR), Surface plasmon c-FMS inhibitor resonance imaging (SPRi), Biosensor, Clinical analysis, Molecular diagnostic, Nanoparticles (NPs) Intro Why SPR in medical analysis? Surface plasmon resonance (SPR) appeared as innovative technology almost 25?years ago, when the first commercial instrumentation was launched on the market by Pharmacia Biosensors Abdominal, a Swedish organization, derived from Pharmacia Abdominal. The company developed an innovative technology from the joint effort of physicists, chemists, biologist, technicians, and computer scientists. Since then, many scientists became a member of the SPR to test new applications in Itga2b various analytical fields, such as food security [1] (e.g., mycotoxins [2], genetically altered organism (GMO) [3]), microbial contamination such as [4], doping analysis [5], laboratory medicine [6, 7], proteomics [8, 9], bacteria detection [10], and also environmental monitoring [11]. Among them, assuredly, medical analysis has also been explored as a fruitful software field. The advantages brought about by current SPR technology include real-time monitoring of the analyte/molecular markers, label free and parallel analysis (with SPRi), minimal sample pretreatment, quantitative response, and very good level of sensitivity and reproducibility, (reported detection limits are in atto- or femtomolar varies and coefficient of variations below 10?%). These features, coupled to miniaturization, make SPR suitable for point of care (POC) diagnostics [12], where fast analysis and multi-analyte detection are mandatory. With this review, we focused on the analysis of target of interest in molecular diagnostics in complex and actual matrices (e.g., serum, saliva, blood, and urine) but also in standard answer when the detection strategy is definitely innovative and c-FMS inhibitor entails the improvement of analytical performances. So the panel of revised analytes includes hormones (steroids and peptides), protein medical markers, antibodies involved in immune disorders, nucleic acids for genetic disease and as medical markers (i.e., miRNA), bacterial cells, and viruses for pathogens detection. So far, most of the study articles come from academic exercises but we are more and more assured that the application of SPR to the medical and medical analysis will gain momentum in the next future. Principles of SPR biosensing The physical principles and the state of the art of surface plasmon resonance [13C17] and surface plasmon resonance imaging-based [18C21] biosensors were reviewed in many excellent works. At the beginning of the 20th century (1902), Solid wood was the 1st scientist who explained the inhomogeneous distribution of light inside a diffraction grating spectrum caused by surface plasmon wave (SPW) [22]. Sixty-six years later on (1968), Kretschmann [23] and Otto [24] rigorously shown the optical excitation of surface plasmons (SPs) with the method of attenuated total reflection (ATR). SPR is definitely defined as a c-FMS inhibitor charge-density oscillation in the interface between two press, with dielectric constants of reverse indicators (e.g., metallic and a dielectric), which generate a surface plasmon wave (SPW) having a propagation constant , expressed by the following equation [13]: is the angular rate of recurrence, is rate of light in vacuum, and are the dielectric constants of dielectric and metallic, respectively. In the metal-dielectric interface the electromagnetic field of the SPW offers as a maximum intensity that exponentially decreases (evanescent wave, EW) into both press with a variable penetration from 100 to 600?nm (for VIS and NIR wavelengths) [25]. Prism couplers, grating couplers, or metal-dielectric waveguides are the configuration utilized for the excitation of surface plasmons but the 1st one represents the most common approach for the plasmon excitation via the attenuated total reflection method (ATR) with Kretschmann geometry becoming also the most suitable for sensing and biosensing applications. In the Kretschmann geometry, the light wave is totally reflected in the boundary between a thin metallic layer (typically platinum or metallic with 50?nm of c-FMS inhibitor thickness) and a high refractive prism coupler (typically in glass). The reflected light excites the surface plasmons of the metallic film generating an EW (or SPW) penetrating the metallic coating (Fig.?1). Open in a separate windows Fig. 1 Inside a SPR biosensor based on a prism coupler and working in Kretschmann geometry with the ATR method, light is completely reflected by a thin platinum coating (50?nm) that excites the surface plasmons.