Surface plasmon resonance sensors for detection of chemical and biological species

Over the past 5 years, more than 100 SPR biosensors for the detection of a variety of chemical and biological analytes were demonstrated. Most of these biosensors are based on prism coupling and angular or wavelength spectroscopy of surface plasmons. Commercial SPR systems have played an important role in the development of detection applications due to their increasing spread and the availability of special SPR platforms and kits dedicated to specific applications (e.g., Biacore Q for food analysis). Data collected in Tables 1-3 illustrate recent applications of SPR biosensors and achieved levels of performance. The performance figures should be compared with caution as performance of an SPR biosensor is a result of a multitude of factors (performance of optical platform, characteristics of the employed biorecognition element, suitability and degree of optimization of the immobilization method, detection format, and methodology), and thus low performance of one part of the biosensor (e.g., optical platform) can be compensated for by high performance of another component (e.g., biorecognition elements). Clearly, analytes implicated in food safety have received the most attention (Table 1). Bacterial pathogens such as E. coli and Salmonella were the most frequently targeted analytes. Detection limits below 102 bacteria/mL were reported. A great deal of research has been devoted to the development of SPR biosensors for other significant groups of analytes such as Staphylococcal enterotoxins (best demonstrated LODs < 1 ng/mL and antibiotics (best LODs < 1-10 ng/ mL depending on the substance). Several analytes have been detected also in complex food matrices. In the field of medical diagnostics (Table 2), the most attention has been paid to the development of SPR sensors for the detection of cancer markers (best LODs < 1-100 ng/mL) and antibodies (best LODs < 1-100 ng/mL). However, most of the detection experiments were performed in buffers rather than in clinical samples. The development of SPR biosensors for environmental monitoring (Table 3) has focused mainly on the detection of pesticides. The best LODs ranged from 1 to 100 pg/mL, depending on the analyte. Detection experiments were performed in buffers or real-world water samples. Conclusions: In the past, 5 years, SPR biosensor technology has made substantial advances in terms of both sensor hardware and biospecific coatings. SPR biosensors have been applied for the detection of a variety of chemical and biological analytes. We envision that the performance of SPR biosensor technology will continue to evolve and that advanced SPR sensor platforms combined with novel biospecific surfaces with high resistance to the nonspecific binding will lead to robust SPR biosensors enabling rapid, sensitive, and specific detection of chemical and biological analytes in complex samples in the field. These biosensors will benefit numerous important sectors such as medical diagnostics, environmental monitoring, and food safety and security. Abbreviations: ATR, attenuated total reflection; CCD, charge-coupled device; DNA, deoxyribonucleic acid; ELISA, enzyme-linked immunosorbent assay; LED, light-emitting diode; LOD, limit of detection; MALDI-TOF, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; RIU, refractive index unit; RNA, ribonucleic acid; scFvs, single-chain antibody fragment; SAM, self-assembled monolayer; SP, surface plasmon; SPR, surface plasmon resonance; WDM, wavelength division multiplexing. © 2008 American Chemical Society.