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Cancer Cell Targeting With Functionalized Quantum Dot-Encoded Polyelectrolyte Microcapsules
摘要： Imaging agents and drug carriers are commonly targeted toward cancer cell through functionalization with specific recognition molecules. Quantum dots (QDs) are fluorescent semiconductor nanocrystals whose extraordinary brightness and photostability make them attractive for direct fluorescent labeling of biomolecules or optical encoding of the membranes and cells. Here, we analyse the cytotoxicity of QD-encoded microcapsules, validate an approach to the activation of further functionalization with monoclonal antibody Trastuzumab, a humanized monoclonal antibody targeting the extracellular domain of the human epidermal growth factor receptor 2 (HER2) and already in clinical use for the treatment of HER2 positive breast cancer. In addition, we characterize the cell-specific targeting activity of the resultant bio-conjugate by immunofluorescence assay (IFA) and real-time analysis of interaction of the conjugates with live HER2 overexpressing human breast cancer cells. We demonstrate, that encapsulation of QDs into the polymer shell using the layer-by-layer deposition method yields highly fluorescent polyelectrolyte microcapsules with a homogeneous size distribution and biocompatibility upon in vitro treatment of cancer cells. Carbodiimide surface activation ensures optimal disperse and optical characteristics of the QD-encoded microcapsules before antibody conjugation. The prepared conjugates of the microcapsules with cancer-specific monoclonal antibody targeting HER2 provide sufficiently sensitive and specific antibody-mediated binding of the microcapsules with live cancer cells, which demonstrated their potential as prospective cancer cell–targeting agents.
关键词： cytotoxicity,monoclonal antibody,polyelectrolyte microcapsules,quantum dots,cancer cell targeting
更新于2025-11-21 11:24:58
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Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots
摘要： Semiconductor nanocrystals or quantum dots (QDs) have unique optical and physical properties that make them potential imaging tools in biological and medical applications. However, concerns over the aqueous dispersivity, toxicity to cells, and stability in biological environments may limit the use of QDs in such applications. Here, we report an investigation into the cytotoxicity of aqueous dispersed CdSe(S) and CdSe(S)/ZnO core/shell QDs in the presence of human colorectal carcinoma cells (HCT-116) and a human skin fibroblast cell line (WS1). The cytotoxicity of the precursor solutions used in the synthesis of the CdSe(S) QDs was also determined in the presence of HCT-116 cells. CdSe(S) QDs were found to have a low toxicity at concentrations up to 100 μg/mL, with a decreased cell viability at higher concentrations, indicating a highly dose-dependent response. Meanwhile, CdSe(S)/ZnO core/shell QDs exhibited lower toxicity than uncoated QDs at higher concentrations. Confocal microscopy images of HCT-116 cells after incubation with CdSe(S) and CdSe(S)/ZnO QDs showed that the cells were stable in aqueous concentrations of 100 μg of QDs per mL, with no sign of cell necrosis, confirming the cytotoxicity data.
关键词： core/shell QDs,HCT-116,water dispersive QDs,WS1,bioapplications of QDs,aqueous synthesis,in vitro cytotoxicity of QDs
更新于2025-11-21 11:08:12
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Sulfur doped carbon nitride quantum dots with efficient fluorescent property and their application for bioimaging
摘要： Heteroatom doping can drastically alter electronic characteristics of carbon nitride quantum dots, thus resulting in unusual properties and related applications. Herein, we used sulfur as the doping element and investigated the influence of doping on the electronic distribution of carbon nitride and the corresponding fluorescent property. A simple synthetic strategy was applied to prepare sulfur-doped carbon nitride (S-g-C3N4) quantum dots through ultrasonic treatment of bulk S-g-C3N4. Characterization results demonstrated that the prepared S-g-C3N4 quantum dots with an average size of 2.0 nm were successfully prepared. Fluorescent properties indicated that S-g-C3N4 quantum dots have an emission peak at 460 nm and cover the emission spectra region up to 550 nm. Furthermore, the fluorescent intensity is greatly increased due to the sonication of bulk S-g-C3N4 into quantum dots. As a result, S-g-C3N4 quantum dots not only show a blue cell imaging, but have a bright green color. Therefore, S-g-C3N4 quantum dot is a promising candidate for bioimaging benefiting from the efficient fluorescent property, good biocompatibility, and low toxicity.
关键词： Doped carbon nitride,Fluorescent property,In vitro cytotoxicity,Quantum dots,Bioimaging
更新于2025-11-14 17:04:02
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Fluorescence and absorption studies of DNA-Pd(II) complex interaction: Synthesis, spectroanalytical investigations and biological activities
摘要： Novel palladium(II) complexes (7a–7e) of substituted quinoline derivatives were synthesized. The complexes were characterized using various techniques such as thermogravimetric analysis (TGA), elemental analysis, conductance measurement, mass, absorption, infra‐red (IR), 1H NMR, 13C NMR and energy‐dispersive X‐ray spectroscopy (EDX). Complexes for herring sperm DNA (HS DNA) binding were explored and absorption titration and the binding constant (Kb) as well as Gibb's free energy were evaluated. Complex 7d exhibited the highest binding constant, therefore the thermodynamic parameters of 7d at different temperatures were evaluated. To support the results of the absorption titration, fluorescence titration, viscosity measurement and molecular docking studies were performed. The fluorescence quenching data as evaluated from Stern–Volmer equation were used to calculate KSV, K f and the number of binding sites. The results of all these studies were in good agreement with the absorption study. DNA electrophoretic mobility was performed to explore the possible application of metal complexes as artificial metallonucleases. The antibacterial activity of the complexes was accessed against different pathogenic bacteria and cytotoxicity was measured using brine shrimp and S. pombe.
关键词： Stern–Volmer equation,absorption titration,thermodynamic parameters,cytotoxicity,fluorescence quenching,artificial metallonuclease
更新于2025-09-23 15:23:52
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Valorization of mutant Bacillus licheniformis M09 supernatant for green synthesis of silver nanoparticles: photocatalytic dye degradation, antibacterial activity, and cytotoxicity
摘要： The present study reports the optimization of a green method for the synthesis of silver nanoparticles (AgNPs) via reduction of Ag+ ions using cell-free supernatant of mutant Bacillus licheniformis M09. UV–Visible spectroscopy showing an absorption peak at ~ 430 nm confirmed the synthesis of AgNPs. Transmission electron microscope (TEM) analysis exhibited spherical AgNPs within the size range of 10–30 nm. Fourier transform infrared (FTIR) measurements assured the presence of effective functional molecules which could be responsible for stabilizing the AgNPs. X-ray diffraction (XRD) pattern verified the crystalline nature of AgNPs. Furthermore, the synthesized AgNPs showed an excellent photocatalytic degradation of methylene blue dye in less than 3 h under visible light proving their potential as a catalytic agent for bioremediation for next-generation dye degradation in effluent treatment. The AgNPs demonstrated antimicrobial activity against Gram-positive and Gram-negative foodborne pathogens which endorsed its suitability as agents to extend shelf-life in food packaging and food safety applications. The results also revealed a strong concentration-dependent cytotoxicity of AgNPs against human breast adenocarcinoma cells (MCF-7), while 15.07 μg/mL of IC50 was attained. The outcome suggests the possible application of these AgNPs in nanomedicine formulations. Thus, these findings propose promising ways for the valorization of the waste fermentation supernatant left after cell harvesting and desired metabolite extraction.
关键词： Methylene blue,Antibacterial,Photocatalytic dye degradation,Cytotoxicity effects,Bacillus licheniformis M09,Silver nanoparticles
更新于2025-09-23 15:23:52
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Visible light sensitive Ag/TiO2/graphene composite as a potential coating material for control of Campylobacter jejuni
摘要： Infectious diarrhea caused by the food borne pathogen, Campylobacter jejuni, is a major threat to public health worldwide leads high incidence of child mortality each year. In the present study, hydrothermal synthesis of Silver-Graphene-TiO2 nanocomposites along with TiO2, TiO2-Graphene and TiO2-silver nanocomposites was done and the samples were characterized using X-ray diffraction (XRD), tunneling electron microscopy (TEM) and UV-Vis Spectroscopy. Effect of silver and graphene addition on the broad spectrum antibacterial ability of TiO2 was studied under visible light. Moreover, the effects on bacterial survival, membrane integrity, cellular motiltiy and biofilm formation of C. jejuni were also evaluated. A synergetic effect of silver and graphene on Silver-Graphene-TiO2 nanocomposites was observed as indicated by its increased visible light sensitivity and enhanced antibacterial activity under visible light compared to its parent derivatives. Silver-Graphene-TiO2 composites effectively reduced growth and caused leakage of protein and DNA from C. jejuni cell. Atomic Force Microscopy was used to confirm bacterial cell damage. Besides, it also reduced motillity, hydrophobicity and autoaggregation of C. jejuni and showed excellent inhibition of biofilm formation. Furthermore, no significant cytotoxicity of synthesized nanoparticles was observed in human cell lines. We propose that Silver-Graphene-TiO2 composites can be used as effective antimicrobial agents to control the spread of C. jejuni by preventing both bacterial growth and biofilm formation.
关键词： TiO2,Campylobacter jejuni,photocatalytic,nanocomposite,biofilm,graphene,cytotoxicity,silver
更新于2025-09-23 15:23:52
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Functional chlorin gold nanorods enable to treat breast cancer by photothermal/photodynamic therapy
摘要： Background: The existing chemo/radiotherapy fail to eliminate cancer cells due to the restriction of either drug resistance or radio tolerance. The predicament urges researchers to continuously explore alternative strategy for achieving a potent curative effect. Methods: Functional chlorin gold nanorods (Ce6-AuNR@SiO2-d-CPP) were fabricated aiming at treating breast cancer by photothermal/photodynamic therapy (PTT/PDT). The nanostructure was developed by synthesizing Au nanorods as the photothermal conversion material, and by coating the pegylated mesoporous SiO2 as the shell for entrapping photosensitizer Ce6 and for linking the D-type cell penetrating peptide (d-CPP). The function of Ce6-AuNR@SiO2-d-CPP was verified on human breast cancer MCF-7 cells and MCF-7 cells xenografts in nude mice. Results: Under combinational treatment of PTT and PDT, Ce6-AuNR@SiO2-d-CPP demonstrated a strong cytotoxicity and apoptosis inducing effects in breast cancer cells in vitro, and a robust treatment efficacy in breast cancer-bearing nude mice. The uptake mechanism involved the energy-consuming caveolin-mediated endocytosis, and Ce6-AuNR@SiO2-d-CPP in PTT/PDT mode could induce apoptosis by multiple pathways in breast cancer cells. Conclusion: Ce6-AuNR@SiO2-d-CPP demonstrated a robust efficacy in the treatment of breast cancer by photothermal/photodynamic therapy. Therefore, the present study could offer a new promising strategy to treat the refractory breast cancer.
关键词： PTT/PDT,apoptosis,cellular uptake,functional chlorin gold nanorods,cell penetrating peptide,cytotoxicity
更新于2025-09-23 15:23:52
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Universal existence of fluorescent carbon dots in beer and assessment of their potential toxicity
摘要： Nanosized materials may produce adverse physiological effects or potential health risks due to their unique physical and chemical properties. Herein, the universal presence of fluorescent carbon dots (CDs) in commercial beers was confirmed through a systematic survey. The beer CDs were roughly spherically shaped in appearance and emitted bright blue fluorescence under ultraviolet light with quantum yields (QYs) ranging from 1.42% to 3.92%. Furthermore, digestion, biodistribution, and cytotoxicity assessments of CDs from Snow beer were conducted as an example. The CDs were significantly quenched during in vitro digestion. The dynamic distribution of CDs in mice showed that they easily accumulated in the intestine and liver, and more importantly, the beer CDs were found in the brain, which indicated that they were able to cross the blood–brain barrier. Acute toxicity of the beer CDs was evaluated using BALB/c mice, and the results revealed that the biochemical parameters of mice after administration of a single dose of 2 g kg?1 body weight were almost same as those of the control groups. Histological analysis showed no obvious organ damage in the tested mice. The in vitro results indicated that CDs dispersed onto both the cell membrane and the cytoplasm of MC3T3-E1 cells, alter the cell cycle progression, and caused cell apoptosis at high doses. This work reports the potential risk of CDs in beer and provides valuable information regarding CDs in food.
关键词： beer,cytotoxicity,biodistribution,Carbon dots,digestion
更新于2025-09-23 15:23:52
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Tuning the selectivity of N-alkylated styrylquinolinium dyes for sensing of G-quadruplex DNA
摘要： Selective and sensitive detection of G-quadruplex DNA structures is an important issue and attracts extensive interest. To this end, numerous small molecular fluorescent probes have been designed. Here, we present a series of N-alkylated styrylquinolinium dyes named Ls-1, Ls-2 and Ls-3 with varying side groups at the chain end. We found that these dyes exhibited different binding behaviors to DNAs, and Ls-2 with a sulfonato group at the chain end displayed sensitivity and selectivity to G-quadruplex DNA structures in vitro. The characteristics of this dye and its interaction with G-quadruplex DNA were comprehensively investigated by means of UV–vis spectrophotometry, fluorescence, circular dichroism and molecular docking. Furthermore, confocal fluorescence images and MTT assays indicated dye Ls-2 could pass through membrane and enter the living HepG2 cells with low cytotoxicity.
关键词： N-Alkylated styrylquinolinium dye,Living HepG2 cell,G-quadruplex DNA,Cytotoxicity
更新于2025-09-23 15:22:29
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Luminescent silica mesoparticles for protein transduction
摘要： Unlike silica nanoparticles, the potential of silica mesoparticles (SMPs) (i.e. particles of submicron size) for biological applications in particular the in vitro (let alone in vivo) cellular delivery of biological cargo has so far not been sufficiently studied. Here we examine the potential of luminescent (namely, octahedral molybdenum cluster doped) SMPs synthesised by a simple one-pot reaction for the labelling of cells and for protein transduction into larynx carcinoma (Hep-2) cells using GFP as a model protein. Our data demonstrates that the SMPs internalise into the cells within half an hour. This results in cells that detectably luminesce via conventional methods. In addition, the particles are non-toxic both in darkness and upon photo-irradiation. The SMPs were modified to allow their functionalisation by a protein, which then delivered the protein (GFP) efficiently into the cells. Thus, the luminescent SMPs offer a cheap and trackable alternative to existing materials for cellular internalisation of proteins, such as the HIV TAT protein and commercial protein delivery agents (e.g. Pierce?).
关键词： protein transduction,cytotoxicity,silica,Octahedral molybdenum cluster,cellular uptake
更新于2025-09-23 15:21:21