- 标题
- 摘要
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- 实验方案
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Laser-inscribed contact lens sensors for the detection of analytes in the tear fluid
摘要： Tears exhibit compositional variations as a response to ocular and systemic metabolic conditions, and they can therefore be used for the assessment of physiological health. Here, microfluidic contact lenses were developed as wearable platforms for in situ tear pH, glucose, protein, and nitrite ions sensing. The microfluidic system was inscribed in commercial contact lenses by CO2 laser ablation. The microchannel consisted on a central ring with four branches, and biosensors were embedded within microcavities located at the branches ends. The device was tested with artificial tears and colorimetric readouts were performed using a smartphone-MATLAB algorithm based on the nearest neighbor model. Sensors responded within a time range of 15 seconds, and yielded sensitivities of 12.23 nm/pH unit, 1.4 nm/mmolL-1 of glucose, 0.49 nm/gL-1 of proteins, and 0.03nm/μmolL-1 of nitrites. Contact lens sensing platforms may provide on-eye tears screening with applications in the monitoring of the ocular health both in clinics and at point-of-care settings.
关键词： biomarkers,biosensors,tear fluid,Contact Lenses,point-of-care diagnostics
更新于2025-09-23 15:21:01
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Sensing biomarkers with plasmonics
摘要： The detection of biomarkers is critical for enabling early disease diagnosis, monitoring the progression, and tracking the effectiveness of therapeutic intervention. Plasmonic sensors exhibit a broad range of analytical capabilities, from the rapid generation of colorimetric readouts to single-molecule sensitivity in ultralow sample volumes, which have led to their increased exploration in bioanalysis and point-of-care applications. This perspective presents selected accounts of recent developments on the different types of plasmonic sensing platforms, the pervasive challenges and outlook on the pathway to translation. We highlight the sensing of upcoming biomarkers including microRNA, circulating tumor cells, exosomes, and cell-free DNA, and discuss the opportunity of utilizing plasmonic nanomaterials and tools for biomarker detection beyond biofluids, such as in tissues, organs, and disease sites. The integration of plasmonic biosensors with established and upcoming technologies of instrumentation, sample pre-treatment, and data analysis will help realize their translation to clinical settings for improving healthcare and enhancing the quality of life.
关键词： plasmonics,exosomes,biomarkers,microRNA,biosensors,circulating tumor cells,cell-free DNA
更新于2025-09-23 15:21:01
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Towards Smart Selective Sensors exploiting a novel approach to connect Optical Fiber Biosensors in Internet
摘要： The selective detection of pollutants in water in a laboratory scenario has been presented by authors exploiting low-cost optical biosensors based on plastic optical fibers (POFs) and biological or bio-mimetic receptors. For instance, the detection in water of naphthalene, perfluoroalkyl and polyfluoroalkyl substances (PFAs) have been investigated with interesting detection limits when compared to those obtained by using different expensive traditional approaches (e.g. liquid chromatography-mass spectrometry with high performances). In this work, we have developed and tested a novel approach used in a smart measuring system to use POF sensors in situ for the remote measures of pollutants in water for smart cities applications. More specifically, we have used different water-glycerin solutions to test the novel sensor system based on a Raspberry PI connected to the Internet and to a spectrometer, a light source, a POF sensor, and two computers connected to Internet used as client and server.
关键词： optical fiber sensors,water quality,pollutants,software,biosensors,Plastic optical fibers (POFs),Internet of Things (IoT)
更新于2025-09-23 15:21:01
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[IEEE SoutheastCon 2018 - St. Petersburg, FL (2018.4.19-2018.4.22)] SoutheastCon 2018 - Advanced Nanomaterials for Bio-Monitoring
摘要： Biomedical and diagnostic detection/monitoring are of great importance to society, as these areas directly impact our daily lives. This need is prevalent in the workings of wearable biosensors, as the biosensor market is projected to be a $US 22.5 billion dollar industry by 2020. Hence, the development of sensors utilizing the often enhanced properties of nanoscale materials is at the forefront of wearable analytical chemistry. Nanoscience presents an almost endless amount of novel materials, as their properties differ from their bulk counterparts. Many of the interactions with these nanomaterials remain unexplored, leaving a need for investigation. Both the structure and the materials should be soft and mechanically robust enough to bend, stretch, fold, and twist in response to the motion of the wearer. Here, electrospun polymer fibers have been used as wearable sensors, and further functionalized with a wide loading range of carbon nanomaterials via layer-by-layer and vacuum techniques to accommodate multiple analyte detection schemes in sweat. The data demonstrates the success of a nanocomposite sensor at monitoring in an accurate, selective, and reproducible manner. It is capable of outputting currents, at low voltages (< 1 V), that can easily be read via a portable/wearable device, enhancing the sensor’s attractiveness for wearable/flexible devices.
关键词： nanomaterials,advanced materials,wearable,nanosensors,biosensors
更新于2025-09-23 15:21:01
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Carbon Dots as Theranostic Agents || Carbon Dots for Cell Imaging and Diagnostics
摘要： Not only CDs, but many carbon allotropes showing graphitic structure, i.e., honeycomb-like arrangement of carbon atoms, have shown potential for various applications in electronic devices in biosensors and bioimaging agents. Some examples of these are 0D fullerene [274], diamond nanocrystals [123] and carbon dots (CDs), as well as 1D CNT [275], 2D graphene QD (GQDs) [276] and graphene [277]. However, it must be mentioned here that although CDs and GQDs have similar quantum-confined fluorescent carbon materials, CDs have been more used as biosensors and bioimaging agents [278]. Both CD and GQD are mainly composed of sp2 carbon, oxygen and nitrogen elements and other doped heteroatoms [24, 101]; the different spatial arrangements of carbon atoms exhibit distinctive physical and chemical properties [279]. Unlike GQD, the CDs do not have perfect crystal structures [42]. Moreover, CDs exhibit luminance at size < 10 nm, whereas GQDs have size up to 100 nm [280, 281] and are luminescent. Generally, CDs display strong optical absorption in the UV region, with a tail extending out into the visible range (Figure 5.1a), i.e., 280–360 nm. The absorption band could be regulated via surface passivation or modification. CDs show the excitation-dependent emission properties in wavelength and intensity (Figure 5.1b). Other properties that make CD more applicable for biomedical applications are their low cost, high quantum yield, abundant source, low cytotoxicity, and superior chemical and photo stability. Wang et al. [282] have evaluated the cytotoxicity of the CDs prepared by different combinations of precursor of CDs and molecules used for surface functionalization. It is found that in terms of their nanoscale structure and configuration CDs are not intrinsically cytotoxic. The cytotoxicity of CD depends on the selection of surface passivation molecules.
关键词： quantum yield,theranostic agents,bioimaging,carbon dots,photoluminescence,biosensors,cytotoxicity
更新于2025-09-23 15:21:01
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Modulation of localized surface plasmon resonances of a silver nanoparticle array upon the presence of MoS2 coatings or underlying thin films
摘要： There has been recently a growing interest in studying light-matter coupling using supported metallic nanostructures arranged into periodic arrays. The influence on the layer thickness of two-dimensional materials such as molybdenum disulfide MoS2 on the plasmonic behaviour of these arrays has become of great relevance due to the favorable bonding between S (sulfide atom) and metal atoms such as gold and silver as well as the variation of optical transition of MoS2 depending on the atomic thickness of the film. In this work, we have numerically studied the change in absorption spectra of an ordered array of silver nanoparticles AgNPs when attached to glass as well as to glass coated with different layers of MoS2. This arrangement was compared to an AgNPs attached to glass and post coated with MoS2 films of increasing thickness. It was shown that an overcoating of four MoS2 layers results in an increased plasmonic sensitivity compared to uncoated glass/AgNPs interface. Replacing the glass substrate by glass coated with MoS2 of different thickness and with added AgNPs shows a significant to the red shift with increasing MoS2 layers. This band is due to strong excitation-plasmon coupling of the silver lattice with MoS2 layers. Important is the fact that the electrical field is strongly enhanced beneath the MoS2/AgNPs barrier. One also observes a significant enhancement of the sensitivity. Hence, the design of more sensitive AgNPs/MoS2 based-plasmonic biosensors could be reached. Indeed, we show that AgNPs coating with few layers of MoS2 leads to approximately a 210.26% higher sensitivity.
关键词： Sensitivity,MoS2,Silver nanoparticle array,BioSensors,Localized surface plasmon resonance
更新于2025-09-23 15:21:01
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A Biomimetic Plasmonic Nanoreactor for Reliable Metabolite Detection
摘要： Reliable monitoring of metabolites in biofluids is critical for diagnosis, treatment, and long-term management of various diseases. Although widely used, existing enzymatic metabolite assays face challenges in clinical practice primarily due to the susceptibility of enzyme activity to external conditions and the low sensitivity of sensing strategies. Inspired by the micro/nanoscale confined catalytic environment in living cells, the coencapsulation of oxidoreductase and metal nanoparticles within the nanopores of macroporous silica foams to fabricate all-in-one bio-nanoreactors is reported herein for use in surface-enhanced Raman scattering (SERS)-based metabolic assays. The enhancement of catalytical activity and stability of enzyme against high temperatures, long-time storage or proteolytic agents are demonstrated. The nanoreactors recognize and catalyze oxidation of the metabolite, and provide ratiometric SERS response in the presence of the enzymatic by-product H2O2, enabling sensitive metabolite quantification in a “sample in and answer out” manner. The nanoreactor makes any oxidoreductase-responsible metabolite a candidate for quantitative SERS sensing, as shown for glucose and lactate. Glucose levels of patients with bacterial infection are accurately analyzed with only 20 μL of cerebrospinal fluids, indicating the potential application of the nanoreactor in vitro clinical testing.
关键词： metabolic assays,metabolic testing,macroporous silica foams,biomimetic nanoreactors,SERS biosensors,enzymes
更新于2025-09-23 15:19:57
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Double Fano resonances in hybrid disk/rod artificial plasmonic molecules based on dipole-quadrupole coupling
摘要： Fano resonance can be achieved by the destructive interference between a superradiant bright mode and a subradiant dark mode. A variety of artificial plasmonic oligomers have been fabricated to generate Fano resonance for its extensive applications. However, the Fano resonance in plasmonic oligomer systems comes from the interaction of all metal particles, which greatly limits the tunability of the Fano resonance. Besides, only a single Fano resonance is supported by many existing plasmonic oligomers, while multiple Fano resonances mostly occur in complex and multilayer structures, whose fabrication is greatly challenging. Here, a simple asymmetric plasmonic molecule consisting of a central metal disk and two side-coupled parallel metal rods is demonstrated. The simulation and experimental results clearly show that double Fano resonances appear in the transmission spectrum. In addition, the two Fano peaks can be independently tuned and single/double Fano peak switching can be achieved by changing one rod length or the gap distances between the rods and the disk. The modulation method is simple and effective, which greatly increases the tunability of the structure. The proposed asymmetric artificial plasmonic molecule can have applications in multi-channel optical switches, filters and biosensors. Moreover, the controllable plasmonic field intensity in the gap between the disk and rods also provides a new control means for plasmon-induced photocatalytic reactions and biosynthesis.
关键词： plasmonic oligomers,biosynthesis,Fano resonance,filters,optical switches,biosensors,asymmetric plasmonic molecule,plasmon-induced photocatalytic reactions,double Fano resonances
更新于2025-09-23 15:19:57
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How quantum dots aggregation enhances F??rster??Resonant Energy Transfer
摘要： As luminescent quantum dots (QDs) are known to aggregate themselves through their chemical activation by carbodiimide chemistry and their functionalization with biotin molecules, we investigate both effects on the fluorescence properties of CdTe QDs and their impact on F?rster Resonant Energy Transfer (FRET) occurring with fluorescent streptavidin molecules (FA). First, the QDs fluorescence spectrum undergoes significant changes during the activation step which are explained thanks to an original analytical model based on QDs intra-aggregate screening and inter-QDs FRET. We also highlight the strong influence of biotin in solution on FRET efficiency, and define the experimental conditions maximizing the FRET. Finally, a free-QD-based system and an aggregated-QD-based system are studied in order to compare their detection threshold. The results show a minimum concentration limit of 80 nM in FA for the former while it is equal to 5 nM for the latter, favouring monitored aggregation in the design of QDs-based biosensors.
关键词： fluorescence spectroscopy,biosensors,FRET,quantum dots,Biochemical functionalization
更新于2025-09-23 15:19:57
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Laser Micromachining of Lithium Niobate-Based Resonant Sensors towards Medical Devices Applications
摘要： This paper presents a micromachining process for lithium niobate (LiNbO3) material for the rapid prototyping of a resonant sensor design for medical devices applications. Laser micromachining was used to fabricate samples of lithium niobate material. A qualitative visual check of the surface was performed using scanning electron microscopy. The surface roughness was quantitatively investigated using an optical surface profiler. A surface roughness of 0.526 μm was achieved by laser micromachining. The performance of the laser-micromachined sensor has been examined in different working environments and different modes of operation. The sensor exhibits a Quality-factor (Q-factor) of 646 in a vacuum; and a Q-factor of 222 in air. The good match between the modelling and experimental results shows that the laser-micromachined sensor has a high potential to be used as a resonance biosensor.
关键词： medical devices,laser micromachining,sensors,lithium niobate,biosensors
更新于2025-09-23 15:19:57