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Fabrication of gold-silver core-shell nanoparticles for performing as ultrabright SERS-nanotags inside human ovarian cancer cells
摘要： This paper presents the fabrication and characterization of new gold-silver core-shell nanoparticles labeled with para-mercaptobenzoic acid (4MBA) molecules and demonstrates their use as SERS-nanotags with ultra-bright traceability inside cells and ability to convey spectrally-coded information about the intracellular pH by means of Surface-Enhanced Raman Spectroscopy (SERS). Unlike to previous reported studies, our fabrication procedure includes in the first step the synthesis of chitosan-coated gold nanoparticles as a seed material with subsequent growing of a silver shell. The bimetallic core-shell structure is revealed by transmission electron microscopy (TEM), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), energy-dispersive X-ray elemental mapping (EDX) and the presence of two interacting localized surface plasmon resonance (LSPR) modes in UV-Vis extinction spectrum. The high SERS activity and sensitivity of as fabricated 4MBA-chit-Au-AgNPs nano-constructs to different pH in solution is investigated under 532 and 633 nm laser lines excitation. Next, in view of future studies in cancer diagnosis, the in vitro antiproliferative effects of SERS-nanotags against human ovarian adenocarcinoma cells (NIH:OVCAR-3) are evaluated. The capacity to operate as bright SERS nanotags with precise localization at a single cell level as well as intracellular pH indicators is clearly demonstrated by performing cell imaging under scanning confocal Raman microscopy.
关键词： core-shell nanoparticles,pH sensors,ovarian cancer cells,chitosan,SERS tags
更新于2025-11-21 11:24:58
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Coordination geometry-induced optical imaging of <scp>l</scp> -cysteine in cancer cells using imidazopyridine-based copper( <scp>ii</scp> ) complexes
摘要： Overexpression of cysteine cathepsins proteases has been documented in a wide variety of cancers, and enhances the L-cysteine concentration in tumor cells. We report the synthesis and characterization of copper(II) complexes [Cu(L1)2(H2O)](SO3CF3)2, 1, L1 = 3-phenyl-1-(pyridin-2-yl)imidazo[1,5-a]pyridine, [Cu(L2)2(SO3CF3)]SO3CF3, 2, L2 = 3-(4-methoxyphenyl)-1-pyridin-2-yl-imidazo[1,5-a]pyridine, [Cu(L3)2(H2O)](SO3CF3)2, 3, L3 = 3-(3,4-dimethoxy-phenyl)-1-pyridin-2-yl-imidazo[1,5-a]pyridine and [Cu(L4)2(H2O)](SO3CF3)2, 4, L4 = dimethyl-[4-(1-pyridin-2-yl-imidazo[1,5-a]pyridin-3-yl)phenyl]amine as 'turn-on' optical imaging probes for L-cysteine in cancer cells. The molecular structure of complexes adopted distorted trigonal pyramidal geometry (τ, 0.68–0.87). Cu–Npy bonds (1.964–1.989 ?) were shorter than Cu–Nimi bonds (2.024–2.074 ?) for all complexes. Geometrical distortion was strongly revealed in EPR spectra, showing gk (2.26–2.28) and Ak values (139–163 × 10?4 cm?1) at 70 K. The d–d transitions appeared around 680–741 and 882–932 nm in HEPES, which supported the existence of five-coordinate geometry in solution. The Cu(II)/Cu(I) redox potential of 1 (0.221 V vs. NHE) was almost identical to that of 2 and 3 but lower than that of 4 (0.525 V vs. NHE) in HEPES buffer. The complexes were almost non-emissive in nature, but became emissive by the interaction of L-cysteine in 100% HEPES at pH 7.34 via reduction of Cu(II) to Cu(I). Among the probes, probe 2 showed selective and efficient turn-on fluorescence behavior towards L-cysteine over natural amino acids with a limit of detection of 9.9 × 10?8 M and binding constant of 2.3 × 105 M?1. The selectivity of 2 may have originated from a nearly perfect trigonal plane adopted around a copper(II) center (～120.70°), which required minimum structural change during the reduction of Cu(II) to Cu(I) while imaging Cys. The other complexes, with their distorted trigonal planes, required more reorganizational energy, which resulted in poor selectivity. Probe 2 was employed for optical imaging of L-cysteine in HeLa cells and macrophages. It exhibited brighter fluorescent images by visualizing Cys at pH 7.34 and 37 °C. It showed relatively less toxicity for these cell lines as ascertained by the MTT assay.
关键词： optical imaging,cancer cells,turn-on fluorescence,imidazopyridine,L-cysteine,Copper(II) complexes
更新于2025-11-21 11:08:12
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Freezing Induced Turn-on Modality for Real-time Imaging in Cryosurgery
摘要： Cryosurgery has attracted great attention for the treatment of tumors due to its obvious advantages. However, it still remains a challenge to determine the volume of frozen tissues in real-time, which greatly lowers the therapeutic efficacy of cryosurgery and hinders its broad application for the treatment of cancers. Herein, we report a freezing induced turn-on strategy for selective real-time imaging of frozen cancer cells. As a type of aggregation induced emission (AIE) fluorogen, TABD-Py molecules interact specifically with ice crystals and form aggregates at the ice/water interface. Consequently, bright fluorescent emission appears upon freezing. Note that TABD-Py molecules are enriched only in the cancer cells and exhibit high biocompatibility as well as low cytotoxicity, therefore a freezing induced turn-on imaging modality for cryosurgery is developed, which will certainly maximize therapeutic efficacy of cryosurgery in treating tumors.
关键词： aggregation induced emission,cancer cells,real-time imaging,freezing,cryosurgery
更新于2025-09-23 15:23:52
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Functionalized fluorescent carbon nanoparticles for sensitively targeted of folate-receptor-positive cancer cells
摘要： The folic acid-functionalized fluorescent carbon dots (FA-CDs) was synthesized via the assembly of FA to the surface of CDs. A facile hydrothermal method with proline and ethylenediamine as precursors was used to fabricate CDs. The as-prepared CDs possessed active amino groups where the CDs could be further engineered for the conjugation with FA. The uptake of the as-synthesized FA-CDs by FR positive MCF-7 cells (FR++) and HepG-2 cells (FR+) via receptor-mediated endocytosis was demonstrated by confocal laser scanning microscopy, which is further verified by a comparative study with FR-negative PC-12 cells (FR-). The bright fluorescence can be observed in FR positive MCF-7 cells while negligible fluorescence was observed in PC-12 cells with low-expressed FR, demonstrating that FA-CDs could accurately identify FR-positive cancer cells from normal cells. The FA-CDs shared favorable biocompatibility, excellent optical properties and ultra-low toxicity etc. Holding these superior properties, the FA-CDs was implemented as a highly effective platform for biological labeling and imaging, which may provide a innovative vision for cancer diagnosis and succeeding personalized therapy.
关键词： Folic acid-functionalized,Targeted bioimaging,Cancer cells,Carbon dots
更新于2025-09-23 15:22:29
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Tuning of carbon dots emission color for sensing of Fe3+ ion and bioimaging applications
摘要： Herein, we report a facile one-step synthetic strategy for fabrication of three (blue, green and yellow) fluorescent color carbon dots (CDs) from tomato (Solanum lycopersicum). The as-synthesized CDs showed emission peaks at 450, 520 and 560 nm for blue, green and yellow color CDs when excited at 370, 420 and 460 nm, respectively. Using tomato as a carbon source, the fabricated three fluorescent color CDs showed good water dispersity and high quantum yield. The analytical performances of three fluorescent color CDs are evaluated by detecting Fe3+ ion in biofluids and iron tablets. Upon the addition of Fe3+ ion under optimal conditions, the fluorescence intensity of three fluorescent color CDs was quenched linearly over the range of 0.1 to 2.0 μM. This method opens a new analytical strategy to quantify Fe3+ ion in iron tablets and biofluids with high sensitivity. Further, the uptake of three fluorescent color CDs into HeLa cells was confirmed by confocal laser scanning microscopy. Intracellular experiments demonstrated that the three fluorescent color CDs were effectively internalized the cells and show excellent biocompatibility and low toxicity, suggesting that the CDs can be used as good candidates for biomedical applications.
关键词： Fluorescent carbon dots,Fe3+ ion,Cancer cells,Fluorescence spectroscopy and microscopy,Tomato
更新于2025-09-23 15:22:29
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Ratiometric Electrogenerated Chemiluminescence Cytosensor Based on Conducting Polymer Hydrogel Loaded with Internal Standard Molecules
摘要： A sensitive and reliable bimodal electrochemiluminescent (ECL) system based on CdTe Quantum Dots (QDs) and luminol as double luminophores is constructed. CdTe QDs tagged with the aptamer (CdTe-Apt 2) of cancer cells are used as the detection signal, while luminol molecules are used as internal standards. The electrodeposited polyaniline based conducting polymer hydrogel (CPH) on the electrode surfaces improves the biocompatibility and conductivity of the sensing interfaces effectively. Furtherly, electron transfer is probably much easier when luminol and coreactant potassium persulfate (K2S2O8) immobilized in the CPH compared to that in solution. Cancer cells are captured to the electrode surface by another aptamer linked to the Au nanoparticles immobilized in the CPH through Au-S bonds. In the developed bimodal ECL system, internal standard method is used to quantify cancer cells by comparing the differences in sensitivity of the double-peak ECL signals with that of target analytes. The internal standard method of ECL strategy can provide very accurate detection results in complex environment because interferences in the system can be eliminated through the self-calibration of two emission spectra. A linear relation is found based on the ?ECLCdTe/?ECLluminol against the concentration of cancer cells within 100 to 6500 cells mL-1 under optimized conditions. The developed ratiometric ECL cytosensor with internal standard can significantly improve the accuracy and reliability of cell assay in complex biological media, demonstrating promising applications in healthcare monitoring and clinical diagnostics.
关键词： Cytosensor,Electrogenerated Chemiluminescence,Internal standard method,Conducting Polymer Hydrogel,Cancer cells
更新于2025-09-23 15:21:21
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New Unsymmetrical Bisacridine Derivatives Noncovalently Attached to Quaternary Quantum Dots Improve Cancer Therapy by Enhancing Cytotoxicity toward Cancer Cells and Protecting Normal Cells
摘要： The use of nanoparticles for the controlled drug delivery to cells has emerged as a good alternative to traditional systemic delivery. Quantum dots (QDs) offer potentially invaluable societal benefits such as drug targeting and in vivo biomedical imaging. In contrast, QDs may also pose risks to human health and the environment under certain conditions. Here, we demonstrated that a unique combination of nanocrystals core components (Ag-In-Zn-S) would eliminate the toxicity problem and increase their biomedical applications. The alloyed quaternary nanocrystals Ag-In-Zn-S (QDgreen, Ag1.0In1.2Zn5.6S9.4; QDred, Ag1.0In1.0Zn1.0S3.5) were used to transport new unsymmetrical bisacridine derivatives (UAs, C-2028 and C-2045) into lung H460 and colon HCT116 cancer cells for improving the cytotoxic and antitumor action of these compounds. UAs were coupled with QD through physical adsorption. The obtained results clearly indicate that the synthesized nanoconjugates exhibited higher cytotoxic activity than unbound compounds, especially toward lung H460 cancer cells. Importantly, unsymmetrical bisacridines noncovalently attached to QD strongly protect normal cells from the drug action. It is worth pointing out that QDgreen or QDred without UAs did not influence the growth of cancer and normal cells, which is consistent with in vivo results. In noncellular systems, at pH 5.5 and 4.0, which relates to the conditions of endosomes and lysosomes, the UAs were released from QD-UAs nanoconjugates. An increase of total lysosomes content was observed in H460 cells treated with QDs-UAs which can affect the release of the UAs from the conjugates. Moreover, confocal laser scanning microscopy analyses revealed that QD-UAs nanoconjugates enter H460 cells more efficiently than to HCT116 and normal cells, which may be the reason for their higher cytotoxicity against lung cancer. Summarizing, the noncovalent attachment of UAs to QDs increases the therapeutic efficiency of UAs by improving cytotoxicity toward lung H460 cancer cells and having protecting effects on normal cells.
关键词： lung and colon cancer cells,unsymmetrical bisacridine derivatives,drug-carrier degradation pathway,pH-dependent release,cellular uptake,in vivo antitumor efficacy,Ag-In-Zn-S nanocrystals,cytotoxic activity
更新于2025-09-23 15:21:01
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Plasmonic nano-dumbbells for enhanced photothermal and photodynamic synergistic damage of cancer cells
摘要： The longitudinal surface plasmon resonance of light-irradiated gold nanorods (Au NRs) is generated to enhance the local electric ?elds of Au NR-based nano-dumbbells (NDs), tailored speci?cally by coating mesoporous silica at two poles of Au NRs and embedding photosensitizer indocyanine green (ICG) into the mesopores. The assembled NDs possess a superior uniformity and water dispersity with a strong plasmonic absorption around 800 nm. Time-domain ?nite-difference calculations indicate that the enhanced local electric ?eld of NDs is predominantly distributed in the dumbbells at two poles of Au NRs, which improves the photonic performance of ICG signi?cantly. Illuminated by an 800 nm laser, the fabricated NDs demonstrate an enhanced combination of photothermal and photodynamic effects in comparison to either Au NRs or ICG alone. Synergistic damaging of photothermal and photodynamic combination to nasopharyngeal carcinoma cells has been corroborated experimentally, thus causing substantial cell death under a lower incident near-infrared laser power. This study concludes that the plasmonic NDs combined synergistically with ef?cient photothermal and photodynamic effects are highly promising in cancer therapy.
关键词： photodynamic therapy,photothermal therapy,cancer cells,gold nanorods,indocyanine green,Plasmonic nano-dumbbells
更新于2025-09-23 15:21:01
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Immunomagnetic bead-based bioassay for the voltammetric analysis of the breast cancer biomarker HER2-ECD and tumour cells using quantum dots as detection labels
摘要： An electrochemical magnetic immunosensing strategy was developed for the determination of HER2-ECD, a breast cancer biomarker, and breast cancer cells in human serum. A sandwich assay was performed on carboxylic acid-functionalized magnetic beads (MBs) using a screen-printed carbon electrode (SPCE) as transducer surface. The affinity process was detected using electroactive labels; core/shell streptavidin-modified CdSe@ZnS Quantum Dots (QDs). Cd2+ ions, released from the QDs, were determined by differential pulse anodic stripping voltammetry (DPASV). An assay time of 90 min, with an actual hands-on time of about 20 min, a linear range between 0.50–50 ng·mL?1 of HER2-ECD and a limit of detection of 0.29 ng·mL?1 were achieved. Analysis of live breast cancer cells was also performed using the optimized assay. Breast cancer cell lines SK-BR-3 (a HER2-positive cell line), MDA-MB-231 (a HER2-negative cell line) and MCF-7 (a cell line with low HER2 expression) were tested. The selectivity of the assay towards SK-BR-3 cells was confirmed. A concentration-dependent signal that was 12.5× higher than the signal obtained for the HER2-negative cells (MDA-MB-231) and a limit of detection of 2 cells·mL?1 was obtained.
关键词： Breast cancer,Electrochemical immunoassay,Quantum dots,Cancer cells,Magnetic beads,HER2-ECD
更新于2025-09-23 15:19:57
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The Antibody-Free Recognition of Cancer Cells Using Plasmonic Biosensor Platforms with the Anisotropic Resonant Metasurfaces
摘要： It is vital and promising for portable and disposable biosensing devices to achieve on-site detection and analysis of cancer cells. Although traditional labelling techniques provide an accurate quantitative measurement, the complicated cell staining and high-cost measurements limit its further development. Here, we demonstrate a non-immune biosensing technology. The plasmonic biosensors which is based on anisotropic resonant split ring resonators in terahertz range successfully realize the antibody-free recognition of cancer cells. The dependences of Δf and fitted phase slope (FPS) on the cancer cell concentration at different polarizations give new perspective in hexagonal radar maps. The results indicate that the lung cancer cell A549 and liver cancer cell HepG2 can be distinguished and determined simply based on the enclosed shapes in the radar maps without any antibody introduction. The minimum concentration of identification reduces as low as 1×104 cells/ml and such identification can be kept valid in a large range of cell concentration, ranging from 104 to 105. The construction of two-dimensional extinction intensity cards of corresponding cancer cells based on the wavelet transform method also supplies corresponding information for the antibody-free recognition and determination of two cancer cells. Our plasmonic MBs show a great potential in the determination and recognition of label-free cancer cells, being an alternative to non-immune biosensing technology.
关键词： terahertz,antibody-free biosensing,cancer cells,metasurfaces,continuous wavelet transform
更新于2025-09-23 15:19:57