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Graphene Quantum Dots and Their Applications in Bioimaging, Biosensing, and Therapy
摘要： Graphene quantum dots (GQDs) are carbon-based, nanoscale particles that exhibit excellent chemical, physical, and biological properties that allow them to excel in a wide range of applications in nanomedicine. The unique electronic structure of GQDs confers functional attributes onto these nanomaterials such as strong and tunable photoluminescence for use in fluorescence bioimaging and biosensing, a high loading capacity of aromatic compounds for small-molecule drug delivery, and the ability to absorb incident radiation for use in the cancer-killing techniques of photothermal and photodynamic therapy. Recent advances in the development of GQDs as novel, multifunctional biomaterials are presented with a focus on their physicochemical, electronic, magnetic, and biological properties, along with a discussion of technical progress in the synthesis of GQDs. Progress toward the application of GQDs in bioimaging, biosensing, and therapy is reviewed, along with a discussion of the current limitations and future directions of this exciting material.
关键词： biosensing,quantum dots,drug delivery,nanomedicine,bioimaging,graphene
更新于2025-09-12 10:27:22
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Spectroscopic Evidence of Bloch Surface Waves in the Mid Infrared
摘要： Bloch Surface Waves are surface electromagnetic waves with very low intrinsic losses, existing in both in-plane and out-of plane polarizations, supported by a one-dimensional photonic crystal with an in-gap defect. We have developed thin-film deposition technology on CaF2 prisms suitable for biosensing applications of BSWs in the mid-infrared. Here we report spectroscopic evidence of BSWs, in perfect agreement with theory, in the wavelength range from 4 to 6 micrometers.
关键词： photonic crystal,spectroscopic evidence,mid-infrared,Bloch Surface Waves,biosensing
更新于2025-09-12 10:27:22
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Computational nanoplasmonics in the quasistatic limit for biosensing applications
摘要： The phenomenon of localized surface plasmon resonance (LSPR) provides high sensitivity in detecting biomolecules through shifts in resonance frequency when a target is present. Computational studies in this field have used the full Maxwell equations with simplified models of a sensor-analyte system, or they neglected the analyte altogether. In the long-wavelength limit, one can simplify the theory via an electrostatics approximation while adding geometrical detail in the sensor and analytes (at moderate computational cost). This work uses the latter approach, expanding the open-source PYGBE code to compute the extinction cross section of metallic nanoparticles in the presence of any target for sensing. The target molecule is represented by a surface mesh, based on its crystal structure. PYGBE is research software for continuum electrostatics, written in PYTHON with computationally expensive parts accelerated on GPU hardware, via PYCUDA. It is also accelerated algorithmically via a treecode that offers O(N log N ) computational complexity. These features allow PYGBE to handle problems with half a million boundary elements or more. In this work, we demonstrate the suitability of PYGBE, extended to compute LSPR response in the electrostatic limit, for biosensing applications. Using a model problem consisting of an isolated silver nanosphere in an electric field, our results show grid convergence as 1/N, and accurate computation of the extinction cross section as a function of wavelength (compared with an analytical solution). For a model of a sensor-analyte system, consisting of a spherical silver nanoparticle and a set of bovine serum albumin (BSA) proteins, our results again obtain grid convergence as 1/N (with respect to the Richardson extrapolated value). Computing the LSPR response as a function of wavelength in the presence of BSA proteins captures a redshift of 0.5 nm in the resonance frequency due to the presence of the analytes at 1-nm distance. The final result is a sensitivity study of the biosensor model, obtaining the shift in resonance frequency for various distances between the proteins and the nanoparticle. All results in this paper are fully reproducible, and we have deposited in archival data repositories all the materials needed to run the computations again and recreate the figures. PYGBE is open source under a permissive license and openly developed. Documentation is available at http://pygbe.github.io/pygbe/docs/.
关键词： GPU acceleration,biosensing,localized surface plasmon resonance,PYGBE,electrostatics,nanoparticles,boundary element method,LSPR
更新于2025-09-12 10:27:22
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Plasmonic Nanoparticle-Interfaced Lipid Bilayer Membranes
摘要： Plasmonic nanoparticles are widely exploited in diverse bioapplications ranging from therapeutics to biosensing and biocomputing because of their strong and tunable light?matter interactions, facile and versatile chemical/biological ligand modifications, and biocompatibility. With the rapid growth of nanobiotechnology, understanding dynamic interactions between nanoparticles and biological systems at the molecular or single-particle level is becoming increasingly important for interrogating biological systems with functional nanostructures and for developing nanoparticle-based biosensors and therapeutic agents. Therefore, significant efforts have been devoted to precisely design and create nano?bio interfaces by manipulating the nanoparticles’ size, shape, and surface ligand interactions with complex biological systems to maximize their performance and avoid unwanted responses, such as their agglomeration and cytotoxicity. However, investigating physicochemical interactions at the nano?bio interfaces in a quantitative and controllable manner remains challenging, as the interfaces involve highly complex networks between nanoparticles, biomolecules, and cells across multiple scales, each with a myriad of different chemical and biological interactions.
关键词： Plasmonic nanoparticles,lipid bilayer membranes,therapeutics,biocomputing,nano?bio interfaces,biosensing
更新于2025-09-12 10:27:22
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Lasing characteristics of a pyrromethene597-doped microdisk laser fabricated by the ink-jet printing method
摘要： A microdisk laser based on the fluorinated hyper branched polymer FC-V-50 was fabricated on an FEP (fluorinated ethylene propylene) substrate with the use of the ink-jet printing method. Pyrromethene597 doped 10 wt.% FC-V-50 solution in ethanol was used for the fabrication of a microdisk laser. The FC-V-50 polymer is characterized by a carboxyl functional group, which can be activated and attached to an amine group found in biomolecules. Based on the lasing characteristics, it is found that the microdisk laser has a relatively low lasing threshold of 34.51 μJ mm?2 and a reasonable Q factor of 7.52 × 103 at 586.59 nm. Therefore, the microdisk can be used for biosensing. The root mean square (RMS) of the surface roughness of the microdisk was estimated to be 6.2 nm. The surface roughness results scattering losses and limits the Q factor. This work reports the first demonstration of a microdisk laser based on FC-V-50 for biosensing applications.
关键词： ink-jet printing,microdisk laser,pyrromethene597,biosensing,FC-V-50
更新于2025-09-11 14:15:04
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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) - Simulation of the Plasmonic Properties of Gold Nanosponges with Nanotomographically Reconstructioned Models
摘要： The plasmonic properties of gold nanosponges with nanotomographically reconstructed models are very interesting due to their high internal surface area and the possibility to build a model with the exact same structure as the real sample. In order to better understand the structure-property relationship, the optical properties of gold nanosponges were simulated with the exact same structure as the real sample. The results confirm that the nanosponges have a strong plasmonic effect, which is very similar to the plasmonic effect of gold nanoparticles. The specific internal surface area was computed from the 3D data and compared with the specific internal surface area of the real sample. The results show that the nanosponges have a specific internal surface area of about 20 m2/g, which matches well with the specific internal surface area of the real sample. The nanosponges also show a strong plasmonic effect in the near-infrared region, which is very interesting for applications in photothermal therapy and biosensing.
关键词： optical properties,biosensing,nanotomography,gold nanosponges,plasmonic properties,photothermal therapy
更新于2025-09-11 14:15:04
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DNA‐Functionalized Plasmonic Nanomaterials for Optical Biosensing
摘要： Plasmonic nanomaterials, especially Au and Ag nanomaterials, have shown attractive physicochemical properties, such as easy functionalization and tunable optical bands. The development of this active subfield paves the way to the fascinating biosensing platforms. In recent years, plasmonic nanomaterials–based sensors have been extensively investigated because they are useful for genetic diseases, biological processes, devices, and cell imaging. In this account, a brief introduction of the development of optical biosensors based on DNA-functionalized plasmonic nanomaterials is presented. Then the common strategies for the application of the optical sensors are summarized, including colorimetry, fluorescence, localized surface plasmon resonance, and surface-enhanced resonance scattering detection. The focus is on the fundamental aspect of detection methods, and then a few examples of each method are highlighted. Finally, the opportunities and challenges for the plasmonic nanomaterials–based biosensing are discussed with the development of modern technologies.
关键词： optical,nanomaterials,plasmonic,DNA-functionalized,biosensing
更新于2025-09-11 14:15:04
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Low-cost flexible plasmonic nanobump metasurfaces for label-free sensing of serum tumor marker
摘要： The use of plasmonic metasurface for sensing have great potential on label-free detection of human tumor markers, which could benefit clinical examination. In this work, we adopt nanoimprint and plasma etching to optimize the nanofabrication for low-cost flexible plasmonic metasurface sensors with gold nanobump arrays, which enable facile surface bio-functionality, high sensitivity and simple optical measurement in the visible range. A high bulk refractive index sensitivity of 454.4 nm/RIU is achieved for the prototype plasmonic metasurface sensors at the wavelengths from 620nm to 720 nm. The rapid quantitative tumor marker sensing of carcinoembryonic antigen in human serum samples from less than 10 ng/mL to more than 87 ng/mL is achieved, which demonstrates good agreement with the conventional chemiluminescence immunoassay system and sufficiently covers the threshold tumor marker concentration of 20 ng/mL for early cancer prediction. Our method is capable of low-cost high-throughput manufacturing for flexible lightweight plasmonic metasurface sensors, which will facilitate wide applications on portable biomedical sensing devices for future point-of-care diagnosis and mobile healthcare.
关键词： plasmonics,biosensing,nanoimprint lithography,immunoassay
更新于2025-09-11 14:15:04
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Design of Refolding DNA Aptamer on Single-Walled Carbon Nanotubes for Enhanced Optical Detection of Target Proteins
摘要： DNA aptamer conjugated single-walled carbon nanotube (Aptamer-SWNT) hybrids have demonstrated effective optical biosensors because of its high selectivity and specificity to a target protein, however, the understanding of SWNT hybridization with an aptamer forming a secondary or tertiary structure is still lacking. We study wrapping methods dependent optical biosensing modulation by insulin and platelet-derived growth factor (PDGF) using the Aptamer-SWNT hybrids and the Aptamer-Anchor-SWNT hybrids with a periodically sequenced single-stranded DNA (ssDNA) as anchoring phases. We observe that the refolding nature of the aptamer and its combination with an anchoring phase are critical to the hybridization, where the remarkable optical sensing properties are attributed to the wrapping procedures including the direct wrapping with sonication and the indirect wrapping through dialysis. The tetrameric parallel-stranded G-quadruplex conformation of insulin binding aptamers (IBA) shows an enhanced fluorescence response quenching when using the directly wrapped Aptamer-Anchor-SWNT hybrids. In addition, helix-structural refolding of PDGF binding aptamers (PBA) on the SWNT vicinity under the indirect wrapping exhibits anchoring length-dependent optical modulation. Furthermore, the consecutive centrifuging processes with the indirect wrapping demonstrate fluorescence response brightening, in which the diameter dependent brightening effect is observed by aptamer-protein interactions. This study provides an understanding the underlying conjugation nature of both the Aptamer-SWNT and the Aptamer-Anchor-SWNT hybrids formation, facilitating exceptional optical sensing modules with consideration of refolding feature of aptamers, selection of anchoring phases, wrapping methods and centrifuging process, and the hybridization voyage for DNA-SWNT platforms maneuvers their outcoming optical biosensing capabilities.
关键词： insulin,single-walled carbon nanotubes,PDGF,wrapping methods,optical biosensing,DNA aptamer
更新于2025-09-11 14:15:04
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Determination of the activity of T4 polynucleotide kinase phosphatase by exploiting the sequence-dependent fluorescence of DNA-templated copper nanoclusters
摘要： A fluorometric method is described for the determination of the activity of the enzyme T4 polynucleotide kinase phosphatase (T4 PNKP). A short 3′-terminus phosphorylated DNA strand is hybridized with a long DNA strand to produce a partially double-stranded DNA (dsDNA) substrate. On addition of T4 PNKP, the substrate is dephosphorylated to generate the long dsDNA, and then the long dsDNA acted as a template for synthesizing copper nanoclusters (CuNCs). The dsDNA-templated CuNCs display fluorescence with excitation/emission peak wavelengths of 340/570 nm. The fluorescence is DNA sequence-dependent. A DNA substrate was designed to enhance fluorescence and to reduce the background in order to improve the sensitivity of the assay. The assay has an analytical range that extends from 0.07 U mL?1 to 15 U mL?1 and a detection limit of 0.06 U mL?1.
关键词： Near-zero background,Label-free,Copper nanoclusters,T4 polynucleotide kinase phosphatase activity,Fluorescent biosensing
更新于2025-09-10 09:29:36