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Development of dual quantum dots-based fluorescence-linked immunosorbent assay for simultaneous detection on inflammation biomarkers
摘要： Simultaneous detections of di?erent but clinically relevant biomarkers are of extremely importance in biomedicine. Due to their unique photophysical properties, quantum dots (QDs) are ideally suited for highly sensitive multiplexed determination. Herein, a dual quantum dots-based ?uorescence-linked immunosorbent assay (dQDs-FLISA) for simultaneous and quantitative detection of in?ammation biomarkers (i.e. serum amyloid A (SAA) and C-reactive protein (CRP)) has been established. After being coated by amphiphilic oligomers (poly-maleic acid n-hexadecanol ester, PMAH), the red-QD and green-QD with high quantum yields were used as ?uorescence probes to couple SAA and CRP antibodies, respectively. Cross-reactivity among the SAA and CRP’s antibodies and antigens have been carefully examined by interference experiments, and it was successfully avoided by the speci?c probe adding sequence. Therefore, the assay provided a broad linear analytical range, including SAA quantitative range of 10–1,000 ng mL?1 with linear correlation (R2) of 0.992, and CRP quantitative range of 10–1,000 ng mL?1 with R2 of 0.998. The limit of detections (LODs) for SAA and CRP using dQDs-FLISA were 2.39 ng mL?1 and 6.37 ng mL?1, respectively. The accuracy of the assay has been con?rmed with recoveries of 92.13%–101.85%. More importantly, the assay results showed good speci?city, the QD-antibody probe could couple corresponding antigen (CRP or SAA) high-e?ciently and it could be out of interference of other antigens and substances in serum. Given its good performance, the proposed dQDs-FLISA method o?ers great potential for simultaneous and quantitative detection of other biomarkers in in vitro diagnostic (IVD).
关键词： Quantum dot-based ?uorescence-linked immunosorbent assay,In?ammation biomarkers,Simultaneous detection,Quantum dots
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 4th International Conference on Integrated Circuits and Microsystems (ICICM) - Beijing, China (2019.10.25-2019.10.27)] 2019 IEEE 4th International Conference on Integrated Circuits and Microsystems (ICICM) - A Laser Modulation Driver in 130-nm CMOS Technology for Quantum Key Distribution System
摘要： The imaging of dysregulated cell-surface receptors (or biomarkers) is a potential means of identifying the presence of cancer with high sensitivity and specificity. However, due to heterogeneities in the expression of protein biomarkers in tumors, molecular imaging technologies should ideally be capable of visualizing a multiplexed panel of cancer biomarkers. Recently, surface-enhanced Raman-scattering (SERS) nanoparticles (NPs) have attracted wide interest due to their potential for sensitive and multiplexed biomarker detection. In this review, we focus on the most recent advances in tumor imaging using SERS-coded NPs. A brief introduction of the structure and optical properties of SERS NPs is provided, followed by a detailed discussion of key imaging issues such as the administration of NPs in tissue (topical versus systemic), the optical configuration and imaging approach of Raman imaging systems, spectral demultiplexing methods for quantifying NP concentrations, and the disambiguation of specific versus nonspecific sources of contrast through ratiometric imaging of targeted and untargeted (control) NP pairs. Finally, future challenges and directions are briefly outlined.
关键词： molecular imaging,fiberoptic probes,Biomarkers,cancer detection,nanomedicine,tumors,Raman spectroscopy,biomedical optical imaging
更新于2025-09-19 17:13:59
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Topical dual-probe staining using quantum dot-labeled antibodies for identifying tumor biomarkers in fresh specimens
摘要： Purpose Rapid, intra-operative identification of tumor tissue in the margins of excised specimens has become an important focus in the pursuit of reducing re-excision rates, especially for breast conserving surgery. Dual-probe difference specimen imaging (DDSI) is an emerging approach that uses the difference in uptake/clearance kinetics between a pair of fluorescently-labeled stains, one targeted to a biomarker-of-interest and the other an untargeted isotype, to reveal receptor-specific images of the specimen. Previous studies using antibodies labeled with either enhanced Raman particles or organic fluorophores have shown promising tumor vs. normal diagnostic performance. Yet, the unique properties of quantum dot-labeled antibody complexes (QDACs), which provide spectrally-distinct fluorescence emission from a common excitation source, make them ideal candidates for this application. Herein, we evaluate the diagnostic performance of QDAC-based DDSI in excised xenografts. Procedures Excised fresh specimens of normal tissue and human tumor xenografts with elevated expression of HER2 were stained with a HER2-targeted QDAC and an untargeted QDAC isotype. Stained specimens were imaged on a custom hyperspectral imaging system capable of spectrally separating the quantum dot signatures, and images processed using the DDSI approach. The diagnostic performance of this technique under different incubation temperatures and probe concentrations was evaluated using receiver-operator characteristic analysis. Results HER2-targeted QDAC-DDSI was able to distinguish HER2(+) tumors from normal tissue with reasonably high diagnostic performance; however, this performance was sensitive to temperature during the staining procedure. Area under the curve values were 0.61 when staining at room temperature but increased to over 0.81 when staining at 37 ?C. Diagnostic performance was not affected by increasing stain concentration. Conclusions This study is the first to report dual-probe difference imaging of specimens using QDACs and hyperspectral imaging. Our results show promising diagnostic performance under certain conditions, and compel further optimization and evaluation of this intra-operative margin assessment technique.
关键词： tumor biomarkers,hyperspectral imaging,fresh specimens,quantum dot-labeled antibodies,dual-probe difference specimen imaging
更新于2025-09-19 17:13:59
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Sensitive electrochemical aptasensor for detecting EpCAM with silica nanoparticles and quantum dots for signal amplification
摘要： The epithelial cell adhesion molecule (EpCAM) is a known biomarker of circulating tumor cells that plays an important role in tumor metastasis. The detection of EpCAM is vital for personalized diagnosis and therapy but is challenging because of its extremely low concentration in peripheral blood. In our work, an electrochemical aptasensor has been developed to quantitatively detect EpCAM at low concentrations. A gold electrode modified with an aptamer can capture EpCAM, which can then be further recognized by a second aptamer acting as a signal reporter. To amplify the signal, a silica nanoparticle/CdSe complex has been designed to enhance the detection system. First, silica nanoparticles were synthesized to act as carriers for loading many CdSe quantum dots which are capable of binding with the second aptamer by biotin-streptavidin interactions. A molecule of EpCAM can bind with numerous CdSe quantum dots (QDs) to realize significant signal amplification. By stripping square wave voltammetry (SSWV), concentrations down to 10 aM EpCAM can be successfully detected and quantified based on the newly developed aptasensor. The detection linear range is from 10 aM to 100 pM. This principle can also be extended to other biomarkers when a suitable aptamer or antibody is available. This aptasensor is expected to be a potential tool for the diagnosis, therapeutic evaluation and personalized medical care of cancer patients.
关键词： Quantum dots,Signal amplification,Electrochemical aptasensor,Tumor biomarkers
更新于2025-09-16 10:30:52
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Bioplasmonic paper–based assay for perilipin-2 non-invasively detects renal cancer
摘要： Renal cell carcinoma (RCC) has poor survival prognosis because it is asymptomatic at an early, more curative stage. Recently, urine perilipin-2 (PLIN-2) was demonstrated to be a sensitive and speci?c biomarker for the noninvasive, early detection of RCC and an indispensable indicator to distinguish cancer from a benign renal mass. However, current Western blot or ELISA PLIN-2 assays are complicated, expensive, time-consuming or insensitive, making them unsuitable for routine analysis in clinical settings. Here we developed a plasmonic biosensor based on the high refractive index sensitivity of gold nanorattles for the rapid detection of PLIN-2 in patient urine. The paper-based plasmonic assay is highly sensitive and has a dynamic range of 50 pg/ml to 5 mg/ml PLIN-2. The assay is not compromised by variations in urine pH or high concentrations of interfering proteins such as albumin and hemoglobin, making it an excellent candidate for routine clinical applications. The urine PLIN-2 assay readily distinguished patients with pathologically proven clear cell carcinomas of various size, stage and grade (55.9 [39.5, 75.8] ng/ml, median [1st and 3rd quartile]) from age-matched controls (0.3 [0.3, 0.5] ng/ml), patients with bladder cancer (0.5 [0.4, 0.6] ng/ml) and patients with diabetic nephropathy (0.6 [0.4, 0.7] ng/ml). Urine PLIN-2 concentrations were roughly proportional to tumor size (Pearson coef?cient 0.59). Thus, this cost-effective and label-free method represents a novel approach to conduct a non-invasive population screen or rapid differential diagnosis of imaged renal masses, signi?cantly facilitating the early detection and diagnosis of RCC.
关键词： cancer biomarkers,cancer diagnostics,renal cancer,bioplasmonic assay
更新于2025-09-12 10:27:22
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Quantum Dot-Based Simultaneous Multicolor Imaging
摘要： Quantum dots have attracted a great deal of attention among researchers in optical imaging because of their unique physicochemical properties. Their adjustable size allows quantum dots to emit visible fluorescence with different wavelengths excited by a single light source, allowing them to play an unmatched role in multitarget simultaneous multicolor imaging of tissues and cells compared with other molecular biotechnologies and traditional fluorescent materials. This technology affords real-time observation in situ of multiple biomarkers, allowing us to quantify their expression levels, and helping us to gain a deeper understanding of the interactions among biomolecules and the relationship between biomolecules and disease occurrence, progression, and prognosis. This has potential to aid in clinical diagnosis and treatment decision making.
关键词： Molecular imaging,Imaging,Biomarkers,Multicolor,Quantum dots
更新于2025-09-12 10:27:22
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Quantification of Neuropeptide Y with Picomolar Sensitivity Enabled by Guided-Mode Resonance Biosensors
摘要： Assessing levels of neuropeptide Y (NPY) in the human body has many medical uses. Accordingly, we report the quantitative detection of NPY biomarkers applying guided-mode resonance (GMR) biosensor methodology. The label-free sensor operates in the near-infrared spectral region exhibiting distinctive resonance signatures. The interaction of NPY with bioselective molecules on the sensor surface causes spectral shifts that directly identify the binding event without additional processing. In the experiments described here, NPY antibodies are attached to the sensor surface to impart speci?city during operation. For the low concentrations of NPY of interest, we apply a sandwich NPY assay in which the sensor-linked anti-NPY molecule binds with NPY that subsequently binds with anti-NPY to close the sandwich. The sandwich assay achieves a detection limit of ~0.1 pM NPY. The photonic sensor methodology applied here enables expeditious high-throughput data acquisition with high sensitivity and speci?city. The entire bioreaction is recorded as a function of time, in contrast to label-based methods with single-point detection. The convenient methodology and results reported are signi?cant, as the NPY detection range of 0.1–10 pM demonstrated is useful in important medical circumstances.
关键词： neuropeptide Y,guided-mode resonance biosensor,biomarkers,sandwich assay,optical biosensor
更新于2025-09-12 10:27:22
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Advances in nanoplasmonic biosensors for clinical applications
摘要： Biomarkers are unquestionable biological indicators for diagnosis and therapeutic interventions providing appropriate classification of a wide range of health disorders and risk factors. Nonetheless, the detection and quantification of biomarkers need to be tested with sufficient reliability by robust analytical methods in order to assure clinical performance in health care settings. Since the analytical performance is determined by the sensitivity and specificity of the method employed, techniques have been intensively refined in order to avoid the misinterpretation of results and undesirable bias. Although biomarkers can be detected with the existing analytical techniques, to reproducibly quantify them in decentralized settings or remote locations with the required accuracy is still a challenge. Currently, only a few point-of-care devices for biomarker evaluation are commercially available. Thus, more focused research efforts are needed to overcome these limitations in order to provide universal patient-centered care platforms. To this end, plasmonic biosensors can be conveniently used as portable diagnostic devices for attaining timely and cost-effective clinical outcomes. The development of enhanced performance based on nanoplasmonics technology opens the way for sensor miniaturization, multiplexing and point of care testing. This review covers recent advances and applications of plasmonic and nanoplasmonic biosensors intended for biomarker diagnosis in clinical practice, including cancer, cardiovascular and neurodegenerative diseases. The review specially focuses on: (i) recent progress in plasmonics development including the design of singular nanostructured surfaces, (ii) novel chemical functionalization strategies for the appropriate incorporation of bioreceptors and (iii) plasmonic applications as real operative devices in the clinical field. Future prospects in the use of nanoplasmonic sensor platforms for personalised quantification and management of biomarkers directly in body fluids will also be discussed.
关键词： clinical applications,SPR,point-of-care testing,nanoplasmonic biosensors,biomarkers,LSPR
更新于2025-09-12 10:27:22
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Direct and Label-Free Detection of MicroRNA Cancer Biomarkers Using SERS-Based Plasmonic Coupling Interference (PCI) Nanoprobes
摘要： MicroRNAs (miRNAs), small non-coding endogenous RNA molecules, are emerging as promising biomarkers for early detection of various diseases and cancers. Practical screening tools and strategies to detect these small molecules are urgently needed in order to facilitate the translation of miRNA biomarkers into clinical practice. In this study, a label-free biosensing technique based on surface-enhanced Raman scattering (SERS), referred to as “plasmonic coupling interference (PCI)”, was applied for the multiplex detection of miRNA biomarkers. The sensing mechanism of the PCI technique relies on the formation of a nanonetwork consisting of nanoparticles with Raman labels located between adjacent nanoparticles that are interconnected by DNA duplexes. Due to the plasmonic coupling effect of adjacent nanoparticles in the nanonetwork, the Raman labels exhibit intense SERS signals. Such effect can be modulated by the addition of miRNA targets of interest that act as inhibitors to interfere with the formation of this nanonetwork, resulting in a diminished SERS signal. In this study, the PCI technique is theoretically analyzed and the multiplex capability for detection of multiple miRNA cancer biomarkers is demonstrated, establishing the great potential of PCI nanoprobes as a useful diagnostic tool for medical applications.
关键词： SERS,PCI,miRNAs,cancer biomarkers,MicroRNAs,plasmonic coupling interference,multiplex detection
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Anisotropic Fluorescence Emission at the Surface of 1D-Photonic Crystal Biochips
摘要： Novel disposable optical biochips based on one-dimensional photonic crystals (1DPC) sustaining Bloch surface waves (BSW) are a desirable tool for the detection of several disease-related biomarkers. In particular, cancer biomarkers have gained considerable attention, due to the increasing demand for cancer treatment. Within this framework, the herein proposed optical biochips can quantify low concentration (sub ng/mL) of the ERBB2 breast cancer biomarker in biological complex matrices. To discriminate ERBB2 levels in several different cell lysate samples, we made use of a biosensing platform based on 1DPC biochips and on a reading instrument that can work in both a label-free and a fluorescence detection mode. Such combined configuration provides the advantage of complementary information and lower limit of detection (LoD) in the fluorescence mode [1]. In the label-free configuration the BSW excitation is achieved by a prism coupling system (Kretschmann-Raether configuration), like in the surface plasmon resonance (SPR) technique, resulting in a dip in the angular reflectance spectrum, shifting its position due to the refractive index changes [2]. The fluorescence mode is carried out by making use of dye labeled antibodies bound at the 1DPC surface. Coupling between the dye labels and a BSW results in strongly directional fluorescence emission. The advantages brought by the 1DPC, when compared to metal structures, are smaller energy dissipation and narrower resonances [3]. Presently, there is no study about photobleaching in experiments with BSW sustained by 1DPC, while it is evident that such phenomenon cannot be neglected in biosensing assays carried out close to the LoD, where quantitative and accurate information is needed. Here we report for the first time on cancer detection assays carried out with our platform, in which the trustworthiness of the output is put in doubt by photobleaching, which not only affects the overall emission intensity but also its polarization distribution via the TE and TM BSW modes provided by the 1DPC. The experimental data is interpreted by means of a theoretical model for the orientational distribution of dye labels over time, taking into account the density of the optical states of the 1DPC, photobleaching and rotational diffusion of surface bound emitters. The approach permits to model anisotropic fluorescence emission and to manage photobleaching effects in biosensing assays, leading to their correct interpretation.
关键词： one-dimensional photonic crystals,optical biochips,Bloch surface waves,cancer biomarkers,fluorescence emission,photobleaching
更新于2025-09-12 10:27:22