- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Enzymatic Preparation of Plasmonic-Fluorescent Quantum Dot-Gold Hybrid Nanoprobes for Sensitive Detection of Glucose and Alkaline Phosphatase and Dual-Modality Cell Imaging
摘要： Herein, we develop a route to prepare bifunctional plasmonic-fluorescent quantum dot-gold (QD-Au) hybrid nanoprobes by use of enzymatic reactions. Two bio-enzymes, glucose oxidase (GOx) and alkaline phosphatase (ALP) were chosen for the enzymatic preparation of core-satellite or core-shell type CdSe/ZnS@Au hybrid nanostructures. The enzymatic products, H2O2 and L-Ascorbic acid, of the two enzymes were exploited as mild reducing agents for controlled Au deposition on QD surfaces. The polymer multilayers by layer-by-layer assembly were used to adjust the separation between QD core and plasmonic Au, which can effectively reduce the quenching effect of the Au on QDs. The as-prepared QD@Au hybrid nanostructures are excellent dual-modality imaging nanoprobes, and can be used for fluorescence and dark-field scattering dual-imaging of MCF-7 cells. More importantly, the two enzymatic reaction systems can be explored for sensitive and selective detection of glucose and alkaline phosphatase, respectively, by monitoring the fluorescence spectra change of QD@Au hybrid nanoparticles, which is very useful for the glucose- and ALP-related disease diagnosis.
关键词： Biosensing,Fluorescence,Cell imaging,Enzymatic preparation,Plasmonic
更新于2025-09-19 17:13:59
-
Non-covalent Methods of Engineering Optical Sensors Based on Single-Walled Carbon Nanotubes
摘要： Optical sensors based on single-walled carbon nanotubes (SWCNTs) demonstrate tradeoffs that limit their use in in vivo and in vitro environments. Sensor characteristics are primarily governed by the non-covalent wrapping used to suspend the hydrophobic SWCNTs in aqueous solutions, and we herein review the advantages and disadvantages of several of these different wrappings. Sensors based on surfactant wrappings can show enhanced quantum efficiency, high stability, scalability, and diminished selectivity. Conversely, sensors based on synthetic and bio-polymer wrappings tend to show lower quantum efficiency, stability, and scalability, while demonstrating improved selectivity. Major efforts have focused on optimizing sensors based on DNA wrappings, which have intermediate properties that can be improved through synthetic modifications. Although SWCNT sensors have, to date, been mainly engineered using empirical approaches, herein we highlight alternative techniques based on iterative screening that offer a more guided approach to tuning sensor properties. These more rational techniques can yield new combinations that incorporate the advantages of the diverse nanotube wrappings available to create high performance optical sensors.
关键词： optical biosensing,non-covalent solubilization,selectivity,molecular recognition,near-infrared sensors,single-walled carbon nanotubes (SWCNTs or SWNTs),fluorescence brightness
更新于2025-09-19 17:13:59
-
Plasmonic-Active Nanostructured Thin Films
摘要： Plasmonic-active nanomaterials are of high interest to scientists because of their expanding applications in the field for medicine and energy. Chemical and biological sensors based on plasmonic nanomaterials are well-established and commercially available, but the role of plasmonic nanomaterials on photothermal therapeutics, solar cells, super-resolution imaging, organic synthesis, etc. is still emerging. The effectiveness of the plasmonic materials on these technologies depends on their stability and sensitivity. Preparing plasmonics-active nanostructured thin films (PANTFs) on a solid substrate improves their physical stability. More importantly, the surface plasmons of thin film and that of nanostructures can couple in PANTFs enhancing the sensitivity. A PANTF can be used as a transducer for any of the three plasmonic-based sensing techniques, namely, the propagating surface plasmon, localized surface plasmon resonance, and surface-enhanced Raman spectroscopy-based sensing techniques. Additionally, continuous nanostructured metal films have an advantage for implementing electrical controls such as simultaneous sensing using both plasmonic and electrochemical techniques. Although research and development on PANTFs have been rapidly advancing, very few reviews on synthetic methods have been published. In this review, we provide some fundamental and practical aspects of plasmonics along with the recent advances in PANTFs synthesis, focusing on the advantages and shortcomings of the fabrication techniques. We also provide an overview of different types of PANTFs and their sensitivity for biosensing.
关键词： localized surface plasmon resonance (LSPR),plasmonics,gold nanostructures,biosensing,thin film,lithography,nanohole array,nanofabrication
更新于2025-09-19 17:13:59
-
Novel Nanoplasmonic Structure based Integrated Microfluidic Biosensors for Label-Free in Situ Immune Functional Analysis
摘要： The study of immune functional responses is essential to understanding the central role of the immune system in providing immunological host defense and its intercommunication with other systems. The recent development of integrated microfluidic cytokine biosensors has established a new paradigm to identify, isolate, and study immune cell subtypes, cell functions, and intercellular communications that constitute those responses. In this minireview, we highlight the most recent progress in label-free cytokine detection based on localized surface plasmon resonance optical sensing. We present the applications of newly identified plasmonic nanostructures and the integration with advanced microfluidic devices for novel lab-on-a-chip biosensing systems and discuss the associated challenges and future perspective of such integrative sensing technologies for next-generation immune functional analysis.
关键词： immune functional responses,localized surface plasmon resonance,microfluidic cytokine biosensors,plasmonic nanostructures,lab-on-a-chip biosensing systems
更新于2025-09-19 17:13:59
-
[IEEE 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Berlin, Germany (2019.6.23-2019.6.27)] 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Fabrication of Cavity-Sealed Optical Interferometric Surface Stress Biosensor by thin Film Transfer Technique
摘要： We developed a surface stress sensor based on a MEMS Fabry-Perot interferometer with cavity-sealed structure by technique of nanometer-thick parylene sheet for highly sensitive label-free biosensing. The proposed MEMS interferometer can measure the membrane deflection caused by target molecule adsorption as the spectral shift. The proposed cavity-sealed optical interferometer can prevent physical adsorption to the backside of membrane and refractive index drift in the cavity, leading to improvement of sensitivity. We successfully obtained the spectral shift of 77 nm in 10 minutes with the color change associated with the antigen-antibody reaction with a concentration of 1 ng/ml, which improved by 16.7-fold compared with the conventional sensor.
关键词： MEMS biosensor,Surface stress sensor,label-free biosensing,film transfer technique,Fabry-Perot interferometer
更新于2025-09-16 10:30:52
-
DC-biased optofluidic biolaser for uric acid detection
摘要： Optofluidic biolaser is an emerging technology for chemical and biomedical sensing. However, the sensitivity of optofluidic laser is still limited by the laser threshold condition. In this paper we report a DC-biased optofluidic biolaser for uric acid (UA) detection. Inside a Fabry-Perot laser cavity, a coupled enzyme reaction was employed to transform the detection of UA into the detection of analyte-converted hydrogen peroxide (H2O2). The fluorescent product of the enzyme-catalyzed reaction, resorufin, was employed as gain medium for optofluidic lasing. An optimized concentration of H2O2 was pre-added as a DC bias to counterbalance the requirement of high analyte concentration for lasing. UA detection with a limit of detection of 3.63 μM was achieved with a low sample volume as small as 10 μl. This work provides a sensitive technology using optofluidic biolaser for the detection of substance in human body fluids that can be converted into H2O2.
关键词： Optofluidic laser,uric acid,enzyme catalytic reaction,optical biosensing
更新于2025-09-16 10:30:52
-
Liquid crystal-based capacitive, electro-optical and dielectric biosensors for protein quantitation
摘要： The electrical, electro-optical and dielectric properties of liquid crystals (LCs) are routinely manipulated in liquid-crystal display (LCD) devices, but their potential application in the development of biosensors is still in a nascent stage. In this review, utilising the electrical properties, electro-optical effect and dielectric anisotropy in LCs, we provide insights into several possible modes of label-free biodetection and describe how capacitance, electro-optical and dielectric measurements of various LCs assist in quantitative analysis of biomolecules. It is concluded that the electrically induced biosensing techniques proposed here provides new incentives for researchers to study the interaction between LCs and biomolecules and to resolve technical hurdles facing the development of LC-based biosensors.
关键词： bovine serum albumin,biosensing,dielectric spectroscopy,Electro-optical measurement,protein,capacitance
更新于2025-09-16 10:30:52
-
Covalent Surface Modification Effects on Singlea??Walled Carbon Nanotubes for Targeted Sensing and Optical Imaging
摘要： Optical nanoscale technologies often implement covalent or noncovalent strategies for the modification of nanoparticles, whereby both functionalizations are leveraged for multimodal applications but can affect the intrinsic fluorescence of nanoparticles. Specifically, single-walled carbon nanotubes (SWCNTs) can enable real-time imaging and cellular delivery; however, the introduction of covalent SWCNT sidewall functionalizations often attenuates SWCNT fluorescence. Recent advances in SWCNT covalent functionalization chemistries preserve the SWCNT’s pristine graphitic lattice and intrinsic fluorescence, and here, such covalently functionalized SWCNTs maintain intrinsic fluorescence-based molecular recognition of neurotransmitter and protein analytes. The covalently modified SWCNT nanosensor preserves its fluorescence response towards its analyte for certain nanosensors, presumably dependent on the intermolecular interactions between SWCNTs or the steric hindrance introduced by the covalent functionalization that hinders noncovalent interactions with the SWCNT surface. These SWCNT nanosensors are further functionalized via their covalent handles with a targeting ligand, biotin, to self-assemble on passivated microscopy slides, and these dual-functionalized SWCNT materials are explored for future use in multiplexed sensing and imaging applications.
关键词： single-walled carbon nanotubes,biosensing,fluorescence,imaging,surface functionalization
更新于2025-09-16 10:30:52
-
Dual-Enhanced Raman Scattering-Based Characterization of Stem Cell Differentiation Using Graphene-Plasmonic Hybrid Nanoarray
摘要： Surface-enhanced Raman scattering (SERS) has demonstrated great potential to analyze a variety of bio/chemical molecular interactions within cells in a highly sensitive and selective manner. Despite significant advancements, it remains a critical challenge to ensure high sensitivity and selectivity, while achieving uniform signal enhancement and high reproducibility for quantitative detection of targeted biomarkers within a complex stem cell microenvironment. Herein, we demonstrate an innovative sensing platform, using graphene-coated homogeneous plasmonic metal (Au) nanoarrays, which synergize both electromagnetic mechanism (EM)- and chemical mechanism (CM)-based enhancement. Through the homogeneous plasmonic nanostructures, generated by laser interference lithography (LIL), highly reproducible enhancement of Raman signals could be obtained via a strong and uniform EM. Additionally, the graphene-functionalized surface simultaneously amplifies the Raman signals by an optimized CM, which aligns the energy level of the graphene oxide with the target molecule by tuning its oxidation levels, consequently increasing the sensitivity and accuracy of our sensing system. Using the dual-enhanced Raman scattering from both EM from the homogeneous plasmonic Au nanoarray and CM from the graphene surface, our graphene?Au hybrid nanoarray was successfully utilized to detect as well as quantify a specific biomarker (TuJ1) gene expression levels to characterize neuronal differentiation of human neural stem cells (hNSCs). Collectively, we believe our unique graphene?plasmonic hybrid nanoarray can be extended to a wide range of applications in the development of simple, rapid, and accurate sensing platforms for screening various bio/chemical molecules.
关键词： DNA detection,Surface-enhanced Raman scattering,biosensing,stem cell differentiation,2D nanomaterials
更新于2025-09-12 10:27:22
-
PLASMONIC DIFFRACTION FIELD PATTERN IMAGING COULD RESOLVE ULTRA-SENSITIVE BIO-INFORMATION
摘要： Subwavelength nanohole arrays have been very attractive for label-free biosensing applications as they offer simplicity and flexibility in read-out scheme. Recently, platforms employing imaging-based devices integrated to custom-made light sources and plasmonic nanohole array substrates have been proposed as strong candidates to increase throughput by allowing simultaneous evaluation of binding interactions. Despite their high-throughput and multiplexed nature, these platforms dramatically suffer from sensitivity compared to classical spectrometer-based systems. In this article, we introduced a highly sensitive and plasmonic imaging-based platform that can work with very low analyte concentrations. The system employs a tunable optic filter integrated to a CMOS camera that records diffraction intensity patterns of the transmitted light from a plasmonic biochip composed of periodic nanohole arrays. Monitoring diffraction field intensity variations that correspond to transmission values at different wavelengths within the spectrum, we have successfully reconstructed the transmission spectrum of nanohole arrays. Using bulk solutions, we achieved spectral shifts within the reconstructed spectrum that yields refractive index sensitivities very close to the one calculated from the original spectrum obtained with a spectrometer. Similarly, we showed that our platform yields spectral shift amounts very close to the original one upon the attachment of protein mono- and bilayers. By monitoring plasmonic diffraction field intensity images, created through a very sharp illumination light source overlapping with the plasmonic mode of interest, we experimentally achieved sub-1 ng/mL limit-of-detection. Integrating the plasmonic biochip to a microfluidic chamber, we could monitor protein binding kinetics and determined the associated binding parameters very close to the ones obtained through the classical spectrometer-based analyses. Simultaneously monitoring multiple sensing spots in real-time within the same plasmonic biochip, we demonstrated the high-throughput capability of our plasmonic imaging-based technique. Our results showed the possibility of developing plasmonic read-out platforms that could provide high-throughput and multiplexed biosensing without losing sensitivity when integrating large-scale plasmonic chips with multiple sensing locations to imaging-based devices.
关键词： Nanohole arrays,Plasmonics,Nanofabrication,Diffraction Field Monitoring,Label-free biosensing
更新于2025-09-12 10:27:22