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Wafer-level fabrication of 3D nanoparticles assembled nanopillars and click chemistry modification for sensitive SERS detection of trace carbonyl compounds
摘要： In this work, we develop a new method for fabricating wafer-level gold nanoparticles covered silicon nanopillars (SNPs) combined with surface chemical modification to detect trace level carbonyl compounds based on surface-enhanced Raman scattering (SERS) technique. The SNPs are fabricated with an etching process using nano masks synthesized in oxygen-plasma bombardment of photoresist, and further deposited with gold nanoparticles on the surface, thus forming a 3D “particles on pillars” nanostructure for sensitive SERS detection. The enhancement factor (EF) of the devices for R6G detection can achieve 1.56×106 times compared with a flat Si substrate. We also developed an oximation click chemistry reaction procedure by chemically modifying the nanostructures with aminooxy dodecane thiol (ADT) self-assemble modification. The chip is further integrated with a polydimethylsiloxane (PDMS) microfluidic chamber, which allows fast and convenient detection of trace carbonyl compounds in liquid samples. The SERS detection capability was demonstrated by the dropwise addition of fluorescent carbonyl compounds before and after elution. Furthermore, the device was proved with high surface consistency(<70%) for repeated measurement, which has the potential for ppb(parts per billion) level concentration of carbonyl compounds detection.
关键词： carbonyl compounds,chemical modification,nanopillars,SERS,click chemistry
更新于2025-09-23 15:19:57
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Compact, a??Clickablea?? Quantum Dots Photoligated with Multifunctional Zwitterionic Polymers for Immunofluorescence and In-Vivo Imaging
摘要： We detail the preparation of highly fluorescent quantum dots (QDs), surface-engineered with multifunctional polymer ligands that are compact, readily compatible with strain-promoted click conjugation, and the use of these nanocrystals in immunofluorescence and in-vivo imaging. The ligand design combines the benefits of mixed coordination (i.e., thiol and imidazole) with molecular-scale zwitterion motifs, yielding sterically-stabilized and compact QDs that present a controllable number of azide groups, for easy conjugation to biomolecules via the efficient and selective click chemistry. The polymer coating was characterized using NMR spectroscopy to extract estimates of the diffusion coefficient, hydrodynamic size and ligand density. The azide-functionalized QDs were conjugated to anti-tropomyosin receptor kinase B antibody (α-TrkB), or to the brain-derived neurotrophic factor (BDNF). These conjugates were highly effective for labeling the tropomyosin receptor kinase B (TrkB) in pyramidal neurons within cortical tissue and for monitoring the BDNF induced activation of TrkB signaling in live neuronal cells. Finally, the polymer-coated QDs were applied for in vivo imaging of Drosophila Melanogaster embryo, where the QDs remain highly fluorescent and colloidally stable, with no measurable cytotoxicity. These materials would be of great use in various imaging applications, where small size, ease of conjugation and great colloidal stability for in vivo studies are needed.
关键词： click chemistry,BDNF/TrkB,polymers,surface functionalization,embryo imaging,quantum dots
更新于2025-09-23 15:19:57
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Fluorescent patterns by Selective Grafting of a Telechelic Polymer
摘要： The preparation of patterned ultrathin films (sub-10 nm) composed of end-anchored fluorescently-labeled poly(methyl methacrylate) (PMMA) is presented. Telechelic PMMA was synthesized utilizing activator regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) and consecutively end-functionalized with alkynylated fluorescein by Cu-catalyzed azide-alkyne cycloaddition (CuAAC) 'click' chemistry. The polymers were grafted via the α-carboxyl groups to silica or glass substrates pre-treated with (3-aminopropyl)triethoxysilane (APTES). Patterned surfaces were prepared by inkjet printing of APTES onto glass substrates and selectively grafted with fluorescently end-labeled PMMA to obtain emissive arrays on the surface.
关键词： ATRP,inkjet printing,click chemistry,grafting to,polymer brushes
更新于2025-09-19 17:15:36
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Chromophore Arrays Constructed in the Major Groove of DNA Duplexes Using a Post-Synthetic Strategy
摘要： The construction of zipper-like chromophore-arrays in the major groove of duplex DNA remains a challenge because only a few chromophores for this application have been discovered. To address the challenge, dual-chromophore labeled DNAs having a self-complementary sequence were prepared using a solid-phase, post-synthetic, copper-catalyzed, alkyne-azide cycloaddition. The resulting chromophore-arrays on the labeled DNA duplexes were characterized. The dual-tetraphenylethene (TPE) or dual-pyrene (Py) labeled DNA formed self-complementary B-form duplexes and resulted in the construction of chromophore-arrays in the major groove. The TPE-arrays, in which TPEs were arranged in a zipper-like fashion, slightly destabilized the duplex because of their bulkiness and exhibited aggregation-induced-emission. The Py-arrays, in which Pys were not arranged in a zipper-like fashion, had no effect on duplex stability and exhibited weak excimer emission because Py was sufficiently small for free rotation in the major groove.
关键词： Click chemistry,Aggregation,Tetraphenylethene,Pyrene,Oligonucleotides
更新于2025-09-19 17:15:36
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Dual-Modal Imaging-Guided Precise Tracking of Bioorthogonally Labeled Mesenchymal Stem Cells in Mouse Brain Stroke
摘要： Non-invasive and precise stem cell tracking after transplantation in living subject is very important to monitor both stem cell destinations and their in vivo fate, which was closely related to their therapeutic efficacy. Herein, we developed bicyclo[6.1.0]nonyne (BCN)-conjugated glycol chitosan nanoparticles (BCN-NPs) as a delivery system of dual-modal stem cell imaging probes. Near-infrared fluorescent (NIRF) dye, Cy5.5, was chemically conjugated to the BCN-NPs and then oleic acid-coated superparamagnetic iron oxide nanoparticles (OA-Fe3O4 NPs) were encapsulated into BCN-NPs, in resulting Cy5.5-labeled and OA-Fe3O4 NP-encapsulated BCN-NPs (BCN-dual-NPs). For bioorthogonal labeling of human adipose-derived mesenchymal stem cells (hMSCs), firstly, hMSCs were treated with tetra-acetylated N-azidoacetyl-D-mannosamine (Ac4ManNAz) for generating azide (-N3) groups onto their surface via metabolic glycoengineering. Second, azide groups on the cell surface were successfully chemically labeled with BCN-dual-NPs via bioorthogonal click chemistry in vitro. This bioorthogonal labeling of hMSCs could greatly increase the cell labeling efficiency, safety, and imaging sensitivity, compared to only nanoparticle-derived labeling technology. The dual-modal imaging-guided precise tracking of bioorthogonally labeled hMSCs was tested in the photothrombotic stroke mouse model via intraparenchymal injection. Finally, BCN-dual-NPs-labeled hMSCs could be effectively tracked of their migration from implanted site to brain stroke lesion using NIRF/T2-weighted magnetic resonance (MR) dual-modal imaging for 14 days. Our observation would provide a potential application of bioorthogonally labeled stem cell imaging in regenerative medicine by providing safety and high labeling efficiency in vitro and in vivo.
关键词： metabolic engineering,dual-modal imaging,bioorthogonal click chemistry,stem cell tracking,imaging probe,brain stroke
更新于2025-09-16 10:30:52
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Activated Plasmonic Nanoaggregates for Dark-Field in Situ Imaging for HER2 Protein Imaging on Cell Surfaces
摘要： Dark-?eld microscopy (DFM) based on localized surface plasmon resonance (LSPR) was used for observation of experimental phenomena, which is a hopeful nondamaging and non-photobleaching biological imaging technique. In this strategy, plasma nanoaggregates with stronger scattering e?ciency were formed in the presence of the target, causing a “turn-on” phenomenon, when asymmetry modi?ed AuNPs were introduced as probes with zero LSPR background. First, ?CC probe were designed for the cycloaddition between azide and alkyne Au1 to form AuNP dimers under catalytic action by Cu+, which was obtained from the reduction of Cu2+ by sodium ascorbate. The two kinds of probes were successfully used for the detection of Cu2+ in rat serum. Then, to apply this concept to protein on cells, DNA and antibody were modi?ed on the ?CC probe were proposed for HER2 protein DFM on cells. By designing an aptamer sequence in primer, the rolling circle ampli?cation (RCA) was introduced in HER2 DFM on cells, and the image signal was much brighter than that from no-RCA. The unique design made it easier to discriminate the target signal from background noise in cell DFM. This method might be used in the ?elds of molecular diagnostics and cell imaging.
关键词： click chemistry,rolling circle ampli?cation,localized surface plasmon resonance,AuNPs,HER2 protein,Dark-?eld microscopy
更新于2025-09-16 10:30:52
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Electrostatic Repulsion Controls Efficiency of Cu‐free Click‐Reaction with Azide‐Modified Semiconductor Quantum Dots
摘要： Determination of factors influencing the efficiency of conjugation of various molecules with colloidal semiconductor quantum dots (QDs) is an important step toward their biomedical application. We have utilized controlled strain promoted [3+2] azid-alkyne cycloaddition (SPAAC) as an instrument for studying the influence of charge interaction between QDs and molecules on the efficiency of their conjugation. Azide-modified polymer-encapsulated core-shell CdSe/ZnS QDs, bicyclononyne(BCN)-modified JOE dye and BCN-BHQ1(Black Hole Quencher 1)-modified oligonucleotide duplex were used as model objects for conjugation. Strong surface negative charge of carboxylic QDs was shown to suppress efficient conjugation with negatively charged dsDNA or JOE dye (2',7'-dimethoxy-4',5'-dichloro-fluorescein) molecules. Utilization of zwitter-ionic QDs with reduced surface charge allows significantly enhance the efficiency of QDs conjugation with dsDNA.
关键词： bioconjugation,QDs,click-chemistry,zeta potential,SPAAC
更新于2025-09-12 10:27:22
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Compact quantum dot surface modification to enable emergent behaviors in quantum dot-DNA composites
摘要： Quantum dot (QD) biological imaging and sensing applications often require surface modification with single-stranded deoxyribonucleic acid (ssDNA) oligonucleotides. Furthermore, ssDNA conjugation can be leveraged for precision QD templating via higher-order DNA nanostructures to exploit emergent behaviors in photonic applications. Use of ssDNA-QDs across these platforms requires compact, controlled conjugation that engenders QD stability over a wide pH range and in solutions of high ionic strength. However, current ssDNA-QD conjugation approaches suffer from limitations, such as the requirement for thick coatings, low control over ssDNA labeling density, requirement of large amounts of ssDNA, or low colloidal or photostability, restraining implementation in many applications. Here, we combine thin, multidentate, phytochelatin-3 (PC3) QD passivation techniques with strain-promoted copper-free alkyne-azide click chemistry to yield functional ssDNA-QDs with high stability. This process was broadly applicable across QD sizes (i.e., λem = 540, 560, 600 nm), ssDNA lengths (i.e., 10–16 base pairs, bps), and sequences (poly thymine, mixed bps). The resulting compact ssDNA-QDs displayed a fluorescence quenching efficiency of up to 89% by hybridization with complementary ssDNA-AuNPs. Furthermore, ssDNA-QDs were successfully incorporated with higher-order DNA origami nanostructure templates. Thus, this approach, combining PC3 passivation with click chemistry, generates ssDNA-PC3-QDs that enable emergent QD properties in DNA-based devices and applications.
关键词： ssDNA,click chemistry,DNA origami,quantum dots,fluorescence quenching
更新于2025-09-11 14:15:04
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Controllable “Clicked-to-Assembled” Plasmonic Core–Satellite Nanostructures and Its Surface-Enhanced Fluorescence in Living Cells
摘要： The assembly of noble-metal core?satellite (CS) nanostructures is an appealing means to control their plasmonic properties for applications such as surface-enhanced ?uorescence or Raman scattering. However, till now there is a lack of some rapid or convenient methods to construct stable CS nanostructures. Here, we proposed a “clicked-to-assembly” strategy based on the fast and speci?c “click chemistry” reaction between trans-cyclooctene (TCO) and 1,2,4,5-tetrazine (Tz). The CS nanostructures were constructed within 8 min by simple mixing of TCO- or Tz-modi?ed nanoparticles (TCO-NPs or Tz-NPs) without any catalysts or heating required. Transmission electron microscopy experiments show that the constructed CS nanostructures are uniform, and particularly the number of “satellite” nanoparticles in the core surface is controllable by simply adjusting the feeding ratio of TCO-NPs or Tz-NPs in the reaction. The strong surface plasmon coupling e?ect (SPCE) was observed in these CS nanostructures, which was dependent on the coverage degree, size and composition of the satellite, and core NPs. The nanostructures with tuned surface plasmon resonance (SPR) e?ect were tried for the surface-enhanced ?uorescence in living cells. Such well-de?ned CS nanostructures could potentially serve as e?cient SPR-enhanced ?uorescent probes as diagnostics or biomedical imaging agents in nanomedicine.
关键词： core?satellite nanostructures,surface-enhanced ?uorescence,plasmonic properties,nanomedicine,click chemistry
更新于2025-09-11 14:15:04
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Preparation and characterization of poly (3-hexylthiophene) / carbon nanotubes hybrid material via in-situ click chemistry
摘要： The poly(3-hexylthiophene) - multiwalled carbon nanotube hybrid material (P3HT-MWCNT) was successfully prepared in the Cu(I) / DBU catalyst system via in-situ click reaction. The properties of P3HT-MWCNT were measured by FTIR, 1H-NMR, UV-vis, XRD, TEM, SEM and AFM. The fluorescence spectrum of P3HT-MWCNT proved the covalent bond between P3HT and MWCNT, and P3HT could be coated on the surface of MWCNT. Compared with the physical blends of P3HT and MWCNT, P3HT-MWCNT prepared by click chemistry exhibited better thermal stability and a higher melting point of 243.2 oC. TG results also indicated that P3HT content of P3HT-MWCNT was 21.4%. It was expected to prepare novel organic-inorganic donor-acceptor hybrid material with good solubility, optical and thermal stability, which may be a promising material applied in preparation of organic photoelectron in the future.
关键词： multiwalled carbon nanotubes,chemical modification,poly(3-hexylthiophene),organic-inorganic hybrid material,Click chemistry
更新于2025-09-10 09:29:36