Surface Plasmon Resonance Imaging Biosensor Research Articles

Is Osteopontin a Reliable Biomarker for Endometriosis?

This study aimed to evaluate the concentration of osteopontin in peritoneal fluid and plasma as potential biomarkers for diagnosing endometriosis. Osteopontin levels were measured using surface plasmon resonance imaging (SPRI) biosensors in patients suspected of having endometriosis. Plasma samples were collected from 120 patients, and peritoneal fluid was collected from 86 patients. Based on the detection of endometriosis lesions during laparoscopy, participants were divided into a study group (patients with endometriosis) and a control group (patients without endometriosis). The results showed no significant differences in plasma osteopontin levels between women with endometriosis and the control group (19.86 ± 6.72 ng/mL vs. 18.39 ± 4.46 ng/mL, p = 0.15). Similarly, peritoneal fluid osteopontin concentrations did not differ significantly between patients with and without endometriosis (19.04 ± 5.37 ng/mL vs. 17.87 ± 5.13 ng/mL, p = 0.29). Furthermore, osteopontin levels in both plasma and peritoneal fluid were not significantly associated with the stage of endometriosis, the presence of endometrioma, or the menstrual cycle phase. The findings of this study do not support osteopontin concentration as a reliable biomarker for endometriosis. However, further research is necessary to explore osteopontin’s potential role in the disease.

Application of Surface Plasmon Resonance Imaging Biosensors for Determination of Fibronectin, Laminin-5, and Type IV Collagen in Plasma, Urine, and Tissue of Renal Cell Carcinoma.

Laminin, fibronectin, and collagen IV are pivotal extracellular matrix (ECM) components. The ECM environment governs the fundamental properties of tumors, including proliferation, vascularization, and invasion. Given the critical role of cell-matrix adhesion in malignant tumor progression, we hypothesize that the concentrations of these proteins may be altered in the plasma of patients with clear cell renal cell carcinoma (ccRCC). This study aimed to evaluate the serum, urine, and tissue levels of laminin-5, collagen IV, and fibronectin among a control group and ccRCC patients, with the latter divided into stages T1-T2 and T3-T4 according to the TNM classification. We included 60 patients with histopathologically confirmed ccRCC and 26 patients diagnosed with chronic cystitis or benign prostatic hyperplasia (BPH). Collagen IV, laminin-5, and fibronectin were detected using Surface Plasmon Resonance Imaging biosensors. Significant differences were observed between the control group and ccRCC patients, as well as between the T1-T2 and T3-T4 subgroups. Levels were generally higher in plasma and tissue for fibronectin and collagen IV in ccRCC patients and lower for laminin. The ROC (Receiver operating characteristic) analysis yielded satisfactory results for differentiating between ccRCC patients and controls (AUC 0.84-0.93), with statistical significance for both fibronectin and laminin in plasma and urine. Analysis between the T1-T2 and T3-T4 groups revealed interesting findings for all examined substances in plasma (AUC 0.8-0.95). The results suggest a positive correlation between fibronectin and collagen levels and ccRCC staging, while laminin shows a negative correlation, implying a potential protective role. The relationship between plasma and urine concentrations of these biomarkers may be instrumental for tumor detection and staging, thereby streamlining therapeutic decision-making.

Hydrogen peroxide and glucose detection using surface plasmon resonance imaging biosensor with corrodible silver thin film

A surface plasmon resonance imaging (SPRI)-based biosensor is demonstrated for the detection of both hydrogen peroxide (H2O2) and glucose. The H2O2 to be detected acts as an oxidant and etch the silver film. This process gradually effects on resonance condition and consequently the reflected light intensity at a fixed angle. The etching rate of the silver film shows a clear relation with the H2O2 concentration. Therefore, monitoring the reflected light intensity progressively changing over a few minutes, enables accurate detection of H2O2 concentrations ranging from 0 to 200 μM (within physiological range of 0.25–50 μM), with a remarkable limit of detection (LOD) as low as 40 nM. In this regard, the behavior of the surface plasmon resonance (SPR) dip in response to the reduction of the silver film thickness is predicted by Winspall simulation software. These simulation results are in good agreement with the experimental results. Moreover, the proposed method can be applied to determine glucose concentrations ranging from 0 to 10 mM, encompassing the physiological range of 3–8 mM. This is achieved by observing the generated H2O2 through the enzymatic oxidation reaction between glucose and glucose oxidase (Gox). The sensor demonstrates remarkable sensitivity and selectivity, with a detection limit as low as 175 μM for glucose concentration. Furthermore, accurate measurement of glucose concentration in an actual human serum sample is achievable with the proposed sensor, using the standard addition method. The suggested glucose sensor shows promising prospects for use in routine glucose testing, employing a label-free, real-time, and multiplex detection approach.© 2017 Elsevier Inc. All rights reserved.

20S constitutive proteasome, 20S immunoproteasome, and cathepsin S are high-sensitivity and independent markers of immunological activity in relapsing-remitting type of multiple sclerosis.

Research on the markers of autoimmune response in multiple sclerosis (MS) is still of great importance. The aim of our study was the evaluation of plasma 20S constitutive proteasome, 20S immunoproteasome, and cathepsin S concentrations as potential biomarkers of a relapsing-remitting type of MS (RRMS). Surface plasmon resonance imaging (SPRI) biosensors were used for the evaluation of protein concentrations. Plasma 20S constitutive proteasome, 20S immunoproteasome, and cathepsin S concentrations were significantly higher in RRMS patients compared to the control group. All three parameters were characterized by excellent usefulness in differentiating MS patients from healthy individuals (AUC equal to or close to 1.000). The plasma concentration of analyzed parameters was not correlated with severity of disability in the course of RRMS (EDSS value), the number of years from the first MS symptoms, the number of years from MS diagnosis, or the number of relapses within the 24-month observational period. Our study has shown that plasma concentrations of 20S constitutive proteasome, 20S immunoproteasome, and cathepsin S have promising potential in differentiating RRMS patients from healthy individuals. All of the analyzed parameters were found to be independent of the time of MS relapse and the severity of neurological symptoms. Hence, their potential as highly sensitive and independent circulating markers of RRMS suggests a stronger association with immunological activity (inflammatory processes) than with the severity of the disease.

AuNPs/Ti3C2 Signal-Enhanced Surface Plasmon Resonance Imaging Biosensor for Ultrasensitive Detection of miRNA

AuNPs/Ti3C2 Signal-Enhanced Surface Plasmon Resonance Imaging Biosensor for Ultrasensitive Detection of miRNA

Coffee Ring Effect Enhanced Surface Plasmon Resonance Imaging Biosensor via 2-λ Fitting Detection Method.

SPR biosensors have been extensively used for investigating protein-protein interactions. However, in conventional surface plasmon resonance (SPR) biosensors, detection is limited by the Brownian-motion-governed diffusion process of sample molecules in the sensor chip, which makes it challenging to detect biomolecule interactions at ultra-low concentrations. Here, we propose a highly sensitive SPR imaging biosensor which exploits the coffee ring effect (CRE) for in situ enrichment of molecules on the sensing surface. In addition, we designed a wavelength modulation system utilizing two LEDs to reduce the system cost and enhance the detection speed. Furthermore, a detection limit of 213 fM is achieved, which amounts to an approximately 365 times improvement compared to traditional SPR biosensors. With further development, we believe that this SPR imaging system with high sensitivity, less sample consumption, and faster detection speed can be readily applied to ultra-low-concentration molecular detection and interaction analysis.

Is the leptin/BMI ratio a reliable biomarker for endometriosis?

The aim of this study was to analyze the concentration of leptin in peritoneal fluid and plasma and to assess their role as potential biomarkers in the diagnosis of endometriosis. Leptin adjusted for BMI (leptin/BMI ratio) was measured using surface plasmon resonance imaging (SPRI) biosensors. Patients with suspected endometriosis were included in the study. Plasma was collected from 70 cases, and peritoneal fluid from 67 cases. Based on the presence of endometriosis lesions detected during laparoscopy, patients were divided into a study group and a control group (patients without endometriosis). Leptin/BMI ratio in plasma did not differ between women with endometriosis and the control group (0.7159 ± 0.259 vs 0.6992 ± 0.273, p= 0,7988). No significant differences were observed in peritoneal leptin/BMI ratio levels in patients with and without endometriosis (0.6206 ± 0.258 vs 0.6215 ± 0.264, p= 0,9896). Plasma and peritoneal leptin/BMI ratios were significantly lower in women with endometriosis - related primary infertility compared to women with endometriosis without primary infertility (0.640 ± 0.502 vs 0.878 ± 0.623, p < 0.05). The difference was observed in case of primary infertility, but not in terms of the secondary one. No significant differences were noted between leptin/BMI ratio in the proliferative phase and the secretory phase (0.716 ± 0.252 vs 0.697 ± 0.288, p= 0,7785). The results of present study do not support the relevance of leptin concentration determination as a biomarker of the endometriosis. Due to the limited number of samples in the tested group, further studies are needed to confirm its role.

An Array SPRi Biosensor for the Determination of Follicle-Stimulating Hormone in Blood Plasma.

Follicle-stimulating hormone (FSH) regulates the development, growth, pubertal maturation and reproductive processes of the human body. The determination of serous FSH concentration is significant as an alternative to testicular biopsy in the case of boys suffering from cryptorchidism after orchidopexy, and as a means of determining the menopausal stage in women. The aim of this investigation is to develop a specific array surface plasmon resonance imaging (SPRi) biosensor for the determination of FSH in body liquids such as blood plasma, obtaining sufficient sensitivity to determine FSH at levels characteristic for that hormone in blood plasma, without any signal enhancement. The biosensor consists of a mouse monoclonal anti-FSH antibody attached to the gold surface of a chip via a cysteamine linker. Its linear response range is from 0.08 mIU mL-1 (LOQ) to 20 mIU mL-1, and well covers most of the range of FSH activities found in blood without dilution. The precision of measurement is between 3.2% and 13.1% for model samples, and between 3.7% and 5.6% for spiked plasma samples. Recoveries are in the range from 94% to 108%. The biosensor has good selectivity, and is validated by comparison with ECLE, with good agreement of the results.

Development of an SPRi Test for the Quantitative Detection of Cadherin 12 in Human Plasma and Peritoneal Fluid

A new method for the determination of cadherin 12 (CDH12)—an adhesive protein that has a significant impact on the development, growth, and movement of cancer cells—was developed and validated. The method is based on a biosensor using surface plasmon resonance imaging (SPRi) detection. A quartz crystal microbalance was used to analyze the characteristics of the formation of successive layers of the biosensor, from the linker monolayer to the final capture of CDH12 from solution. The association equilibrium constant (KA = 1.66 × 1011 dm3 mol−1) and the dissociation equilibrium constant (KD = 7.52 × 10−12 mol dm−3) of the anti-CDH12 antibody–CDH12 protein complex were determined. The determined analytical parameters, namely the values determining the accuracy, precision, and repeatability of the method, do not exceed the permissible 20% deviations specified by the aforementioned institutions. The proposed method is also selective with respect to possible potential interferents, occurring in up to 100-fold excess concentration relative to the CDH12 concentration. The determined Limit of Quantification (LOQ = 4.92 pg mL−1) indicates the possibility of performing quantitative analysis in human plasma or peritoneal fluid without the need to concentrate the samples; however, particular attention should be paid to their storage conditions, as the analyte does not exhibit high stability. The Passing–Bablok regression model revealed good agreement between the reference method and the SPRi biosensor, with ρSpearman values of 0.961 and 0.925.

Intensity Interrogation-Based High-Sensitivity Surface Plasmon Resonance Imaging Biosensor for Apoptosis Detection in Cancer.

Intensity interrogation-based surface plasmon resonance imaging (ISPRi) sensing has a simple schematic design and is the most widely used surface plasmon resonance technology at present. In this study, we report the successful development of a novel high-sensitivity ISPRi biosensor and its application for apoptosis detection in cancer cells. By optimizing the excitation wavelength and excitation angle, we achieved a refractive index resolution (RIR) of 5.20 × 10-6 RIU. Importantly, the biosensor has been tested and validated for high-throughput and label-free detection of activated caspase-3 with its specific inhibitor Z-DEVD-FMK in apoptotic cells. Therefore, this study describes a novel molecular imaging system to monitor apoptosis in cancers for disease diagnosis and/or evaluation of therapeutic efficacy of anti-cancer drugs.

A New Approach to the Quantification of Fibroblast Growth Factor 23-An Array Surface Plasmon Resonance Imaging Biosensor.

A new biosensor based on the "surface plasmon resonance imaging (SPRi)" detection technique for the quantification of "fibroblast growth factor 23 (FGF23)" has been developed. FGF23 is mainly produced in bone tissues as a phosphaturic hormone that forms a trimeric complex with "fibroblast growth factor receptor 1 (FGFR1)" and αKlotho upon secretion. FGF23 stimulates phosphate excretion and inhibits the formation of active vitamin D in the kidneys. FGF23 has been shown to play a role in bone carcinogenesis and metastasis. The newly developed method, based on the array SPRi biosensor, was validated-the precision, accuracy, and selectivity were acceptable, and yielded less than ±10% recovery. The rectilinear response of the biosensor ranges from 1 to 75 pg/mL. The limit of detection was 0.033 pg/mL, and the limit of quantification was 0.107 pg/mL. The biosensor was used to determine FGF23 concentrations in the blood plasma of healthy subjects and patients with "clear cell" renal cell carcinoma (ccRCC). The obtained results were compared with those measured through an "enzyme-linked immunosorbent assay (ELISA)". The determined Pearson correlation coefficients were 0.994 and 0.989, demonstrating that the newly developed biosensor can be used as a competitive method for the ELISA.

Evaluation of Proteasome and Immunoproteasome Levels in Plasma and Peritoneal Fluid in Patients with Endometriosis.

Endometriosis is a chronic disease in which the endometrium cells are located outside the uterine cavity. The aim of this study was to evaluate circulating 20S proteasome and 20S immunoproteasome levels in plasma and peritoneal fluid in women with and without endometriosis in order to assess their usefulness as biomarkers of disease. Concentrations were measured using surface plasmon resonance imaging biosensors. Patients with suspected endometriosis were included in the study-plasma was collected in 112 cases and peritoneal fluid in 75. Based on the presence of endometriosis lesions detected during laparoscopy, patients were divided into a study group (confirmed endometriosis) and a control group (patients without endometriosis). Proteasome and immunoproteasome levels in both the plasma (p = 0.174; p = 0.696, respectively) and the peritoneal fluid (p = 0.909; p = 0.284, respectively) did not differ between those groups. There was a statistically significant difference in the plasma proteasome levels between patients in the control group and those with mild (Stage I and II) endometriosis (p = 0.047) and in the plasma immunoproteasome levels in patients with ovarian cysts compared to those without (p = 0.017). The results of our study do not support the relevance of proteasome and immunoproteasome determination as biomarkers of the disease but suggest a potentially active role in the pathogenesis of endometriosis.

Linking aberrant glycosylation of plasma glycoproteins with progression of myelodysplastic syndromes: a study based on plasmonic biosensor and lectin array

Aberrant glycosylation of glycoproteins has been linked with various pathologies. Therefore, understanding the relationship between aberrant glycosylation patterns and the onset and progression of the disease is an important research goal that may provide insights into cancer diagnosis and new therapy development. In this study, we use a surface plasmon resonance imaging biosensor and a lectin array to investigate aberrant glycosylation patterns associated with oncohematological disease—myelodysplastic syndromes (MDS). In particular, we detected the interaction between the lectins and glycoproteins present in the blood plasma of patients (three MDS subgroups with different risks of progression to acute myeloid leukemia (AML) and AML patients) and healthy controls. The interaction with lectins from Aleuria aurantia (AAL) and Erythrina cristagalli was more pronounced for plasma samples of the MDS and AML patients, and there was a significant difference between the sensor response to the interaction of AAL with blood plasma from low and medium-risk MDS patients and healthy controls. Our data also suggest that progression from MDS to AML is accompanied by sialylation of glycoproteins and increased levels of truncated O-glycans and that the number of lectins that allow discriminating different stages of disease increases as the disease progresses.

Multiplexing Biosensor for the Detection of Extracellular Vesicles as Biomarkers of Tissue Damage and Recovery after Ischemic Stroke.

The inflammatory, reparative and regenerative mechanisms activated in ischemic stroke patients immediately after the event cooperate in the response to injury, in the restoration of functions and in brain remodeling even weeks after the event and can be sustained by the rehabilitation treatment. Nonetheless, patients' response to treatments is difficult to predict because of the lack of specific measurable markers of recovery, which could be complementary to clinical scales in the evaluation of patients. Considering that Extracellular Vesicles (EVs) are carriers of multiple molecules involved in the response to stroke injury, in the present study, we have identified a panel of EV-associated molecules that (i) confirm the crucial involvement of EVs in the processes that follow ischemic stroke, (ii) could possibly profile ischemic stroke patients at the beginning of the rehabilitation program, (iii) could be used in predicting patients' response to treatment. By means of a multiplexing Surface Plasmon Resonance imaging biosensor, subacute ischemic stroke patients were proven to have increased expression of vascular endothelial growth factor receptor 2 (VEGFR2) and translocator protein (TSPO) on the surface of small EVs in blood. Besides, microglia EVs and endothelial EVs were shown to be significantly involved in the intercellular communications that occur more than 10 days after ischemic stroke, thus being potential tools for the profiling of patients in the subacute phase after ischemic stroke and in the prediction of their recovery.

UCHL1, besides leptin and fibronectin, also could be a sensitive marker of the relapsing–remitting type of multiple sclerosis

Research on the markers of immunoregulatory response in multiple sclerosis (MS) is still of great importance. The aim of our study was the evaluation of leptin, fibronectin, and UCHL1 concentrations as potential biomarkers of a relapsing–remitting type of MS (RRMS). Surface Plasmon Resonance Imaging (SPRI) biosensors were used for the evaluation of proteins concentrations in 100 RRMS patients and 46 healthy volunteers. Plasma leptin, fibronectin, and UCHL1 concentrations were significantly higher in RRMS patients compared to the control group (p < 0.001, respectively). UCHL1 concentration evaluation revealed the highest diagnostic sensitivity (100%) and negative predictive value (100%) in differentiating MS patients from healthy individuals. There was no significant difference in the UCHL1 concentrations depending on the patient’s sex, the presence of relapse within the last 24 months, and the EDSS value (p > 0.05, respectively). In RRMS patients UCHL1 concentration positively correlated with fibronectin levels (r = 0.3928; p < 0.001). In the current cohort of patients plasma UCHL1 concentration was independent of the time of MS relapse and the severity of neurological symptoms. Thus current study may indicate that plasma UCHL1, besides leptin and fibronectin, also could be a promising high-sensitive potential biomarker of relapsing–remitting type of MS. However, these results should be validated with a larger group of patients, taking into account neuroimaging and cerebrospinal fluid analysis data, and by comparing them to patients with other neurological diseases as a control group.

An Array SPRi Biosensor for the Determination on PARP-1 in Blood Plasma.

A biosensor was developed for the quantification of poly(ADP-ribose) polymerase-1 (PARP-1) in body fluids. An antibody specific for PARP-1 was placed on a chip with cysteamine (linker) and a gold layer. This biosensor has a linear response range (10-1000 pg∙mL-1) under appropriate pH conditions and with an antibody ligand concentration of 5 ng∙mL-1. Plasma samples were diluted with PBS buffer in appropriate quantities so that they fell within the linear range of the calibration curve. The biosensor exhibited suitable precision and accuracy, and good recovery (at levels from 95% to 105%). The method was validated by means of PARP-1 determinations in plasma samples from patients with endometriosis and a control group, using surface plasmon resonance imaging (SPRi) biosensors and an enzyme-linked immunosorbent assay (ELISA) test. The Spearman correlation coefficient was close to 1. PARP-1 may be a marker providing information about pathological changes in the body during endometriosis.

Plasma and Peritoneal Fluid Fibronectin and Collagen IV Levels as Potential Biomarkers of Endometriosis.

Laparoscopy as a diagnostic tool for patients with suspected endometriosis is associated with several potentially life-threatening complications. Therefore, it is imperative to identify reliable, non-invasive biomarkers of the disease. The aim of this study was to analyse the concentrations of fibronectin and type IV collagen in peritoneal fluid and plasma to assess their role as potential biomarkers in the diagnosis of endometriosis. Fibronectin and collagen IV protein levels were assessed by surface plasmon resonance imaging (SPRi) biosensors with the usage of monoclonal antibodies. All patients enrolled in the study were referred for laparoscopy for the diagnosis of infertility or chronic pelvic pain (n = 84). The study group included patients with endometriosis confirmed during surgery (n = 49). The concentration of fibronectin in the plasma (329.3 ± 98.5 mg/L) and peritoneal fluid (26.8 ± 11.1 μg/L) in women with endometriosis was significantly higher than in the control group (251.2 ± 84.0 mg/L, 7.0 ± 5.9 μg/L). Fibronectin levels were independent of endometriosis stage (p = 0.874, p = 0.469). No significant differences were observed in collagen IV levels (p = 0.385, p = 0.465). The presence of elevated levels of fibronectin may indicate abnormalities in cell-ECM signalling during the course of endometriosis, and may be a potential biomarker for early detection.

Surface Plasmon Resonance Imaging Sensor for Detection of Photolytically and Photocatalytically Degraded Glyphosate

Glyphosate is one of the most widely used pesticides, which, together with its primary metabolite aminomethylphosphonic acid, remains present in the environment. Many technologies have been developed to reduce glyphosate amounts in water. Among them, heterogeneous photocatalysis with titanium dioxide as a commonly used photocatalyst achieves high removal efficiency. Nevertheless, glyphosate is often converted to organic intermediates during its degradation. The detection of degraded glyphosate and emerging products is, therefore, an important element of research in terms of disposal methods. Attention is being paid to new sensors enabling the fast detection of glyphosate and its degradation products, which would allow the monitoring of its removal process in real time. The surface plasmon resonance imaging (SPRi) method is a promising technique for sensing emerging pollutants in water. The aim of this work was to design, create, and test an SPRi biosensor suitable for the detection of glyphosate during photolytic and photocatalytic experiments focused on its degradation. Cytochrome P450 and TiO2 were selected as the detection molecules. We developed a sensor for the detection of the target molecules with a low molecular weight for monitoring the process of glyphosate degradation, which could be applied in a flow-through arrangement and thus detect changes taking place in real-time. We believe that SPRi sensing could be widely used in the study of xenobiotic removal from surface water or wastewater.

Application of surface plasmon resonance imaging biosensors for determination of fibronectin, laminin-5 and type IV collagen in serum of transitional bladder cancer patients

The urothelial basement membrane (UBM) contains type IV collagen, laminin-5, and fibronectin. Urothelial neoplasm can break through the UBM underlying the urothelium to invade the lamina propria. Conceptually, all bladder cancer staging over Ta (T1–T4) may demonstrate disturbances in the UBM structure, as well as alterations in the serum concentrations of the studied components. The aim of this study was to determine the blood serum concentration of collagen IV, laminin-5 and fibronectin in bladder cancer patients. Quantification of their concentrations and correlation with various clinicopathological parameters may be useful for making more accurate predictions and identifying high-risk patients. The study included 96 patients with bladder cancer confirmed by transurethral resection or cystectomy and 26 patients with diagnosed cystitis chronica or BPH (benign prostate hyperplasia). Collagen IV, laminin-5 and fibronectin were detected using Surface Plasmon Resonance Imaging biosensors. Significant differences in blood serum concentrations of the studied biomarkers were observed between the control group and bladder cancer patients, as well as between nonmuscle-invasive and muscle-invasive groups. ROC analysis gave satisfactory results for differentiation between the control group and bladder cancer group (AUC 0.92–0.99), with lower values only for collagen IV between nonmuscle-invasive and muscle-invasive patients (AUC 0.71), and a statistically insignificant difference for laminin-5. Laminin-5 concentration was more closely correlated to tumour grade, size and recurrence rate; fibronectin to tumour stage, size and morphology; and collagen IV to tumour stage, grade and recurrence rate. The relations between serum concentrations of the presented biomarkers of the urothelial basement membrane may be useful for bladder cancer detection and for determination of the tumour stage, hence simplifying the making of therapeutic decisions.

High-Sensitive Surface Plasmon Resonance Imaging Biosensor Based on Dual-Wavelength Differential Method.

Intensity interrogation surface plasmon resonance (ISPR) sensing has a simple schematic design and is the most widely used surface plasmon resonance technology at present. However, it has relatively low sensitivity, especially for ISPR imaging (ISPRi). In this paper, a new technique for the real-time monitoring of biomolecule binding on sensor surfaces via ISPRi detection is described. The technique is based on the interrogation of the differential value of two intensities at two specific wavelengths from the reflected light spectrum. In addition, we also optimized the selection of dual-wavelength parameters under different circumstances to achieve the highest sensitivity. The new technique achieved a refractive index resolution (RIR) of 2.24 × 10–6 RIU, which is far beyond that of traditional ISPRi technique. Moreover, our new ISPRi technique also realized the real-time detection of high-throughput biomolecular binding. This study is expected to promote the development of faster and more accurate SPRi technologies.