Surface Plasmon Resonance Imaging Biosensor Research Articles

Levels of Selected Matrix Metalloproteinases-MMP-1, MMP-2 and Fibronectin in the Saliva of Patients Planned for Endodontic Treatment or Surgical Extraction.

Objectives: Composition of saliva reflects the condition of the oral cavity. The aim of the study: Investigation of the concentrations of MMP-1 (Matrix metalloproteinase-1), MMP-2 (Matrix metalloproteinase-2) and fibronectin in the saliva of patients planned for endodontic treatment or surgical extraction. Material and methods: Seventy-five patients with caries and 14 healthy subjects were included in the study. Subjects were divided into group 1, in which 50 patients were planned for endodontic treatment, and group 2, in which 25 patients were planned for surgical extraction. For the measurements, we used a surface plasmon resonance imaging biosensor. Results: We found higher levels of MMP-1, MMP-2 and fibronectin in the saliva of patients planned for dental treatment than in healthy donors. We found lower concentrations of MMP-2 in subjects planned for surgical extraction, than in patients planned for endodontic treatment; however, there were no such differences in salivary concentrations of MMP-1 and fibronectin. There were no statistically significant differences in MMP-1 concentrations in the saliva before and after any type of dental treatment, but contrary to that, we found a statistically significant decrease in MMP-2 concentrations after endodontic treatment and after surgical extraction. We found a significant rise in the concentrations of fibronectin after surgical extraction but not after endodontic treatment. Conclusions: The concentrations of MMP-1 and MMP-2 in the saliva of our patients with caries were increased in comparison to healthy individuals, but after the treatment—so sanation of the oral cavity—we noted a decrease in matrix metalloproteinases (MMPs) levels. MMPs can be found in gingival crevicular fluid and saliva, carious dentin and plaque. According to our observations, the main source of MMPs in patients with caries is probably carious dentin. Increase in the salivary levels of fibronectin (FN) after surgical extraction may be connected with soft tissue injury caused by surgical extraction. Our results are another example of the fact that higher salivary concentrations of MMP-1, MMP-2 and FN can reflect the health status of the oral cavity in patients with caries.

Surface plasmon resonance biosensor using hydrogel-AuNP supramolecular spheres for determination of prostate cancer-derived exosomes.

Based on the hydrogel-AuNP supramolecular sphere (H-Au), a label-free and real-time surface plasmon resonance imaging biosensor has been developed for highly sensitive and specific determination of prostate cancer cell-derived exosomes. After integrating the signal amplification effect of themass cumulative hydrogel and theLSPR effect of AuNPs with high specific aptamer, theSPRi biosensor for exosome detection exhibited a wide linear range from 1.00 × 105 to 1.00 × 107 particles/mL with a limit of detection of1.00 × 105 particles/mL. Most importantly, with a strong correlation between the SPRi signal and the t-PSA value measured by the clinical chemiluminescence immunoassay, this biosensor displayed excellent practicability for human serumanalysis, which exhibits great potential applications in disease diagnosis and bioanalysis. Prostate cancer has been one of the most threatening diseases in human life and health nowadays. In particular, as cancer metastasizes, it is more likely to cause fracture, paraplegia, and even fatal consequences. However, the predominant t-PSA test needs further improvement for the deficiencies of limited specificity and sensitivity, which is prone to false positive. As one of the noninvasive markers of liquid biopsies, exosome has the potential to be a substitute for t-PSA, which can provide specific and predictive information in disease diagnosis and prognosis. Herein, based on the hydrogel-AuNP supramolecular sphere (H-Au), a label-free and real-time surface plasmon resonance biosensor has been developed for highly sensitive and specific detection of prostate cancer cell-derived exosomes. After integrating the signal amplification effect of mass cumulative hydrogel and LSPR effect of AuNPs with high specific aptamer, this developed SPRi biosensor for exosome detection exhibited a wide linear range from 1.00 × 105 to 1.00 × 107 particles/mL with a limit of detection down to 1.00 × 105 particles/mL. Most importantly, with a strong correlation between the SPRi signal and the t-PSA value measured by the clinical chemiluminescence immunoassay, this biosensor displayed excellent practicability in human serum, which exhibited great potential applications in disease diagnosis and bioanalysis.

Plasma aromatase as a sensitive and selective potential biomarker of bladder cancer and its role in tumorigenesis.

Bladder cancer (BCa) is the ninth most common cancer in the world and its early detection is crucial for successful therapy. Unfortunately, there are no satisfactory tools to detect BCa at early stages and BCa's confirmation muscle-invasive. The search for a suitable biomarker is therefore necessary and aromatase is a potential candidate. The purpose of the current study was to determine if aromatase serves as a biomarker of BCa. A Surface Plasmon Resonance Imaging biosensor was applied for the quantification and determination of aromatase. A total of 3 µl blood plasma was used for a single measurement. The results revealed that the aromatase concentration in the plasma of patients with BCa (n=78) ranged from 17.41-57.44 ng/ml. The range determined in healthy donors (n=18) was 2.59-7.74 ng/ml. Additionally, it was revealed that muscle invasive BCa samples exhibited elevated, statistically significant (P=0.01) average aromatase concentrations in blood plasma (38.64 ng/ml) when compared with non-muscle invasive samples (29.83 ng/ml). The results demonstrated that plasma aromatase may serve as an excellent bimarker of BCa with 100% sensitivity, 100% selectivity and an area under the curve value of the reciever operating characteristic curve equal to 1.0. Furthermore, the marker differenciated between muscle-invasive and non muscle-invasive BCa with a sensitivity of 60% and a specificity of 81%. In conclusion, aromatase may serve a role in bladder tumorigenesis.

A biosensor for determination of the circulating biomarker CA125/MUC16 by Surface Plasmon Resonance Imaging

CA125/MUC16 is an ovarian tumor cell marker widely used as a biomarker in epithelial ovarian carcinoma. CA125/MUC16 is also used for evaluation of the ROMA (Risk of Ovarian Malignancy Algorithm) value. In this work, a Surface Plasmon Resonance Imaging (SPRI) biosensor for circulating CA125/MUC16 has been developed. The anti-MUC16 antibody was attached to a gold chip via a cysteamine linker. The EDS/NHS protocol was used for the covalent attachment of the antibody. The developed biosensor is specific for CA125/MUC16, and exhibits good recovery and acceptable precision. Its linear response range (2.2–150 U/ml) is well suited to determination of the marker in the blood serum of a healthy control group and, after appropriate dilution, of patients with ovarian cancer. CA125/MUC16 was determined in two series of real samples: blood serum from patients with ovarian cancer and endometrial cysts. The method was validated by parallel determination of the samples using the chemiluminescent Architect i2000 method.

A New Analytical Method for Determination of Cathepsin L Based on the Surface Plasmon Resonance Imaging Biosensor.

The purpose of this study was to develop a new method for a determination of the cathepsin L—biosensor based on the Surface Plasmon Resonance Imaging technique. The cathepsin L is an endopeptidase, which degrades proteins and plays an important role in various processes occurring in the human body. The detection technique, Surface Plasmon Resonance Imaging, is an optical, label-free technique, which can be used for quantitative determination of the different proteins. In order to bind the enzyme, the cathepsin L inhibitor—RKLLW-NH2 was used. The validation process showed that parameters: precision, accuracy, and selectivity of the method were acceptable. The analytically useful range of the standard curve was 0.50 ng/mL—15.00 ng/mL. The detection and quantification limit of method was 1.67 pg/mL and 5.07 pg/mL, respectively. The usefulness of the developed method was confirmed by the determination of the cathepsin L concentration in the blood plasma of some healthy persons and in the blood plasma of patients. The obtained results were compared with the results obtained by the ELISA. It was found that the correlation between these two methods was very strong, what suggest that the developed method can be used as the competitive method to the ELISA.

Two-dimensional transition metal dichalcogenides mediated long range surface plasmon resonance biosensors

Two-dimensional transition metal dichalcogenides (TMDCs), as promising alternative plasmon supporting materials to graphene, exhibit potential applications in sensing. Here, we propose a TMDCs-mediated long range surface plasmon resonance (LRSPR) imaging biosensor, which shows tremendous improvements in both imaging sensitivity (2) and detection accuracy (10) as compared to conventional surface plasmon resonance (cSPR) biosensors. It is found that the imaging sensitivity of the LRSPR biosensor can be enhanced by the integration of TMDC layers, which is different from the previously reported graphene-mediated cSPR imaging sensor, whose imaging sensitivity decreases with the number of graphene layers. This imaging sensitivity enhancement effect for the TMDCs-mediated LRSPR sensor originates from the propagating nature of the LRSPR at both interfaces of sensing medium/gold and gold/cytop layer (with a matching refractive index as sensing medium). By tuning the thickness of gold film and cytop layer, it is possible to achieve optimized imaging sensitivity for LRSPR sensors with any known integrated number of TMDC layers and an analyte refractive index. The proposed TMDCs-mediated LRSPR imaging sensor could provide potential applications in chemical sensing and biosensing.

Nitride-Based Microarray Biochips: A New Route of Plasmonic Imaging.

The desire to improve human lives has led to striking development in biosensing technologies. While the ongoing research efforts are mostly dedicated to enhancing speed and sensitivity of the sensor, a third consideration that has become increasingly important is compactness, which is strongly desired in emergency situations and personal health management. Surface plasmon resonance imaging (SPRi) is one of the few techniques that can potentially fulfill all the three goals, considering its multiplexed assay capability. However, miniaturizing SPRi biosensors remains elusive as it entails complicated optical gears. Here, we significantly slim the architecture of SPRi devices by visualizing the varied local density of states around analytes. The unusual detection scheme is realized by building a gain-assisted SPRi with InGaN quantum wells (QWs), where the QW-plasmon coupling efficiency hinges on localized refractive index variation. This new modality abolishes the prism, the polarizer, and the beam-tracking components in the most used Kretschmann configuration without compromising the performances.

Immunoproteasome in the Plasma of Pediatric Patients With Moderate and Major Burns, and Its Correlation With Proteasome and UCHL1 Measured by SPR Imaging Biosensors.

The aim of this study was to determine the immunoproteasome concentration in blood plasma of pediatric patients with moderate and major burns and its correlation with circulating proteasome and ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) with surface plasmon resonance imaging biosensor. The study population comprised of 30 patients with moderate (n = 21) and severe burns (n = 9), aged 9 months to 14 years. The control group represented 18 healthy, age-matched patients, admitted for herniotomy. Exclusion criteria were as follows: admission to the hospital later than 6 hours after burn, cardiovascular or immunological diseases, and severe preexisting infections. Mean concentrations of immunoproteasome, 20S proteasome, and UCHL1 in the blood plasma of children with burns-4 to 6 hours, 12 hours, 3 days, 5 days, and 7 days after thermal injury-were above the levels measured in controls. The immunoproteasome, 20S proteasome, and UCHL1 concentrations in the blood plasma of their patients were highest 12 hours after burn, slowly decreased over time, and on the 5th day still were higher than in controls (P < .05). There was a strong correlation between immunoproteasome and 20S proteasome concentrations 6 hours and 5 days after burn, and moderate correlation 12 hours after burn (P < .05). The immunoproteasome concentration is elevated after burn injury and slowly reaches the normal range during the wound healing process. There is strong correlation between immunoproteasome and 20S proteasome concentrations in the serum of children with moderate and major burns. They did not find such correlation between immunoproteasome and UCHL1 concentrations. Immunoproteasome concentration do not correlate with age or sex.

Matrix metalloproteinase-2 and its correlation with basal membrane components laminin-5 and collagen type IV in paediatric burn patients measured with Surface Plasmon Resonance Imaging (SPRI) biosensors

The purpose of this study was the determination of matrix metalloproteinase-2 and its correlation with basal membrane components laminin-5 and collagen type IV in the blood plasma of burn patients measured with Surface Plasmon Resonance Imaging (SPRI) biosensors. Material and methods31 children scalded by hot water who were managed at the Department of Paediatric Surgery between 2014–2015, after primarily presenting with burns in 4–20% TBSA were included into the study (age 9 months up to 14 years, mean age 2,5+1 years). There were 10 girls and 21 boys. Venous blood samples were drawn 2–6h, and 12–16h after the thermal injury, and on the subsequent days 3, 5 and 7. The matrix metalloproteinase-2, collagen type IV and laminin-5 concentrations were assessed using Surface Plasmon Resonance Imaging by the investigators blinded to the other data. ResultsThe MMP-2, laminin-5 and collagen type IV concentrations in the blood plasma of patients with burns, were highest 12–16h after thermal injury, the difference was statistically significant. The MMP-2, laminin-5 and collagen type IV concentrations measured 3 days, 5 days and 7 days after the thermal injury, slowly decreased over time, and on the 7th day reached the normal range, when compared with the concentration measured in controls. ConclusionCurrent work is the first follow-up study regarding MMP-2 in burns. MMP-2, laminin-5 and collagen type IV levels were elevated early after burn injury in the plasma of studied patients, and were highest 12–16h after the injury. MMP-2, laminin-5 and collagen type IV levels were not proportional to the severity of the burn. We believe in the possibility that the gradual decrease of MMP-2, collagen type IV and laminin-5 concentrations could be connected with the process of healing, but to prove it, more investigation is needed in this area. The SPR imaging biosensor is a good diagnostic tool for determination of MMP-2, laminin-5 and collagen type IV in blood plasma of patients with burns.

A highly sensitive SPRi biosensing strategy for simultaneous detection of multiplex miRNAs based on strand displacement amplification and AuNP signal enhancement.

Herein, a dual channel surface plasmon resonance imaging (SPRi) biosensor has been developed for the simultaneous and highly sensitive detection of multiplex miRNAs based on strand displacement amplification (SDA) and DNA-functionalized AuNP signal enhancement. In the presence of target miRNAs (miR-21 or miR-192), the miRNAs could specifically hybridize with the corresponding hairpin probes (H) and initiate the SDA, resulting in massive triggers. Subsequently, the two parts of the released triggers could hybridize with capture probes (CP) and DNA-functionalized AuNPs, assembling DNA sandwiches with great mass on the chip surface. A significantly amplified SPR signal readout was achieved. This established biosensing method was capable of simultaneously detecting multiplex miRNAs with a limit of detection down to 0.15 pM for miR-21 and 0.22 pM for miR-192. This method exhibited good specificity and acceptable reproducibility. Moreover, the developed method was applied to the determination of target miRNAs in a complex matrix. Thus, this developed SPRi biosensing method may present a potential alternative tool for miRNA detection in biomedical research and clinical diagnosis.

SPR imaging biosensor for the quantitation of fibronectin concentration in blood samples

The purpose of this study was presentation of a new biosensor capable of determination of fibronectin. This biosensor was based on the specific interaction of anti-fibronectin antibody produced in rabbit with fibronectin. The surface plasmon resonance imaging (SPRI) technique was used as a detecting method. Optimization and characterization properties of the biosensor were studied. The determination of fibronectin concentration in natural samples was done. The results were compared with a reference method (Enzyme-Linked Immunosorbent Assay-ELISA). The analytically useful dynamic response range of biosensor is between 5 and 400ngmL−1. The detection limit is 1.5ngmL−1 and limit quantification is 5ngmL−1. The proposed SPRI biosensor showed good selectivity for potential interferences. It was applied to determine fibronectin concentrations in plasma of healthy donors and of patients after thermal injury. Good correlations between results obtained using the SPRI biosensor and ELISA test (correlation coefficients for healthy donors 0.996, for patients 0.984) were obtained. The average fibronectin concentration of healthy donors was 140.5±24.6μgmL −1 and the average fibronectin concentration of patients was 601.5±72.1μgmL −1, which was in agreement with results obtained by other investigators. The obtained results indicate that the developed biosensor may be a candidate for monitoring fibronectin concentration in blood samples.

&lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$\text{MoS}_2$&lt;/tex-math&gt; &lt;/inline-formula&gt;-Based Highly Sensitive Near-Infrared Surface Plasmon Resonance Refractive Index Sensor

A surface plasmon resonance imaging biosensor based on $\text{MoS}_2$ deposited on Aluminium substrate is designed for high imaging sensitivity and detection accuracy. The proposed biosensor exhibits better performance than graphene-based biosensor in the near-infrared regime. A high imaging sensitivity of more than 970 $\text{RIU}^{-1}$ is obtained at the wavelength of 1540 nm. The effect of aluminium thickness, number of $\text{MoS}_2$ layers and the refractive index of sensing layer are investigated to obtain an optimized design for high sensor performance. In addition, the sensor performance comparison of $\text{MoS}_2$ and other two-dimensional transition metal dichalcogenide materials based biosensor in the near-infrared regime are also presented. The designed $\text{MoS}_2$ mediated surface plasmon resonance imaging biosensor could provide potential applications in surface plasmon resonance imaging detection of multiple biomolecular interactions simultaneously.

Ultrasensitive Detection of Staphylococcus aureus and Listeria monocytogenes Genomic DNA by Nanoparticle‐Enhanced Surface Plasmon Resonance Imaging

AbstractThe rapid, sensitive and specific detection of pathogenic bacteria is key to the prevention of a variety of foodborne illnesses representing a significant threat to public health. Conventional methods for the detection and identification of pathogens may take up to a few days to yield an answer, and for this reason, efforts have been made to develop new biosensing platforms for the efficient detection of foodborne pathogens. Here we report the use of a nanoparticle‐enhanced surface plasmon resonance (SPR) imaging biosensor for the rapid and femtomolar‐attomolar detection of Staphylococcus aureus and Listeria monocytogenes genomic DNAs. We performed the nanoparticle enhanced SPR imaging detection of pathogen genomic DNAs with no need for the polymerase chain reaction (PCR) pre‐amplification of the sequences to be detected. Here we show that peptide nucleic acid (PNA) probes can discriminate between two pathogenic genomic DNAs. We tested the selectivity of the detection method against control probe sequences or contaminating bovine genomic DNA and demonstrated, for the first time, the attomolar detection of Staphylococcus aureus genomic DNA in the presence of a 10‐fold higher concentration of bovine genomic DNA.

Designing binding kinetic assay on the bio-layer interferometry (BLI) biosensor to characterize antibody-antigen interactions

The Octet biosensors provide a high-throughput alternative to the well-established surface plasmon resonance (SPR) and SPR imaging (SPRi) biosensors to characterize antibody-antigen interactions. However, the utility of the Octet biosensors for accurate and reproducible measurement of binding rate constants of monoclonal antibodies (mAbs) is limited due to challenges such as analyte rebinding, and mass transport limitation (MTL). This study focuses on addressing these challenges and provides experimental conditions to reliably measure kinetics of mAb-antigen interactions. The mAb capture density of less than 0.6 nm was found to be optimal to measure a wide range of binding affinities on Octet HTX biosensor. The titration kinetic and single cycle kinetic assays performed on Octet HTX generated reproducible binding kinetic parameters and correlated with the values measured on Biacore 4000 and MASS-1. Kinetic assays performed on 0.1 nm density mAb surfaces significantly reduced MTL and enabled characterization of picomolar affinity mAbs. Finally, kinetic analysis performed on 150 antibodies to 10 antigens with molecular weights ranging from 21kD to 105kD showed concordance between Octet HTX, Biacore 4000 and MASS-1 (R2 > 0.90). The data presented in this study suggest that under optimal experimental conditions, Octet biosensor is capable of generating kinetic values comparable to SPR/SPRi biosensors.

Exploring sensitivity & throughput of a parallel flow SPRi biosensor for characterization of antibody-antigen interaction

Rapid growth in the field of biotherapeutics has led to an increased demand for high-throughput, label-free biosensors exhibiting high sensitivity. To support the current needs, Sierra Sensors introduced a surface plasmon resonance imaging (SPRi) based biosensor, Molecular Affinity Screening System (MASS-1). We assessed the potential utility of MASS-1 to support Regeneron's therapeutic antibody discovery. A large panel of antibody-antigen interactions was characterized using MASS-1 and the kinetic data were compared with the Biacore 4000 biosensor. Less than 10% deviation in the binding rate constants measured across eight flow channels of MASS-1 was observed. The single injection cycle kinetic assay allowed rapid measurement of binding rate constants for antibody-antigen interactions. MASS-1 sensitivity was independent of protein immobilization level and kinetic analysis performed using ultra-low density mAb surfaces allowed characterization of picomolar affinity interactions without mass transport limitation. High-throughput characterization of a panel of 189 monoclonal antibodies to 13 different antigens with molecular weights ranging from 14kD to 105kD revealed that binding kinetic parameters measured on MASS-1 were comparable to those measured on Biacore 4000. Our data demonstrate that MASS-1 measures reliable binding kinetic parameters and has an appropriate combination of throughput and sensitivity to support discovery and development of therapeutic antibodies.

Overexpression of ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) in serum of children after thermal injury

PurposeThe study aims to determinate concentrations of ubiquitin C-terminal hydrolase 1 (UCHL1), which hydrolyzes amino acids from ubiquitin and cleave di-ubiquitins, in serum of children after thermal injury. Patients/methods42 children scalded by hot water, managed at the Department of Pediatric Surgery, with burns in 4–20% TBSA were included into the study (age 9 months up to 14 years, mean age 2.5±1 years). Blood plasma UCHL1 concentration was assessed in 2–6h, 12–16h, 3d, 5d, and 7d after injury using surface plasmon resonance imaging biosensor. 18 healthy subjects admitted for planned surgeries served as controls. ResultsThe UCHL1 concentration in the blood plasma of patients with thermal injuries reached its peak 12–16h after thermal injury and slowly decreased over time, and still did not reach the normal range on the 7th day after thermal injury. Mean concentrations of UCHL1 after thermal injury were above the range measured in controls (0.12ng/ml): 2–6h after injury – 5.59ng/dl, 12–16h after injury – 9.16ng/dl, 3 days after injury – 6.94ng/dl, 5 days after 5.41ng/dl, 7 days after injury – 4.09ng/dl. ConclusionsWe observed sudden increase in the concentration of UCHL1 2–16h after thermal injury with the slow decrease in the UCHL1 concentration over the time. UCHL1 concentration was proportional to the severity of the burn. Further studies are needed to determine the mechanisms by which UCHL1 contributes to metabolic response following thermal injury.

Methods for 20S Immunoproteasome and 20S Constitutive Proteasome Determination Based on SPRI Biosensors

The 20S proteasome, released into the circulation, is a novel cancer biomarker. It exists in two forms: the constitutive proteasome (20Sc) and the immunoproteasome (20Si), which both have separate diagnostic significance. The aim of this work was to develop new methods for 20Si and 20Sc determination. Five alternative specific biosensors usable with the surface plasmon resonance imaging (SPRI) technique for 20Si determination have been developed. Specific 20Si entrapment on the biosensor surface from an analyzed solution was achieved by means of an immobilized specific 20Si receptor. Four of the biosensors contain newly synthesized specific 20Si receptors, while the fifth contains the inhibitor ONX 0914. A method for 20Sc determination using an SPRI biosensor containing PSI inhibitor has been developed. By the introduction of an inhibitor blocking 20Si, 20Sc is selectively determined. All of the methods developed for 20Si and 20Sc determination exhibit good selectivity and satisfactory precision, recoveries and dynamic response ranges. 20Si and 20Sc were determined in blood plasma samples from healthy donors and patients with acute leukemia. In the case of these patients 20Si was the major component, and its level was more than one order of magnitude higher than in the healthy donors.

Wavelength-Scanning SPR Imaging Sensors Based on an Acousto-Optic Tunable Filter and a White Light Laser.

A fast surface plasmon resonance (SPR) imaging biosensor system based on wavelength interrogation using an acousto-optic tunable filter (AOTF) and a white light laser is presented. The system combines the merits of a wide-dynamic detection range and high sensitivity offered by the spectral approach with multiplexed high-throughput data collection and a two-dimensional (2D) biosensor array. The key feature is the use of AOTF to realize wavelength scan from a white laser source and thus to achieve fast tracking of the SPR dip movement caused by target molecules binding to the sensor surface. Experimental results show that the system is capable of completing a SPR dip measurement within 0.35 s. To the best of our knowledge, this is the fastest time ever reported in the literature for imaging spectral interrogation. Based on a spectral window with a width of approximately 100 nm, a dynamic detection range and resolution of 4.63 × 10−2 refractive index unit (RIU) and 1.27 × 10−6 RIU achieved in a 2D-array sensor is reported here. The spectral SPR imaging sensor scheme has the capability of performing fast high-throughput detection of biomolecular interactions from 2D sensor arrays. The design has no mechanical moving parts, thus making the scheme completely solid-state.

SPRI biosensors for quantitative determination of matrix metalloproteinase-2

The aim of this study was to develop a new, label-free, highly selective Surface Plasmon Resonance Imaging biosensor for the quantitative determination of matrix metalloproteinase-2.

Fast spectral surface plasmon resonance imaging sensor for real-time high-throughput detection of biomolecular interactions.

A fast surface plasmon resonance (SPR) imaging biosensor system based on wavelength interrogation using a liquid crystal tunable filter (LCTF) is presented. The system combines the merits of wide-dynamic detection range offered by the spectral approach and multiplexed high-throughput data collection with a two-dimensional (2-D) biosensor array. The key feature of the reported scheme is a feedback loop that drives the LCTF to achieve fast tracking of the SPR dip movement caused by the binding of target molecules to the sensor surface. Experimental results show that the system is capable of completing an SPR dip measurement within 4 s. Based on using a spectral window of about 100 nm, the experimental dynamic detection range and refractive index resolution are 4.63×10?2??RIU and 5.87×10?6??RIU, respectively. As also demonstrated herein using 2-D microsensor arrays, among the spectral SPR sensors, the reported system is most suitable for multiplexed label-free biosensing applications.