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@#A sandwiched electrochemical immunoassay based on the AuNPs@GSH-CdTe as a signal label, which formed by GSH-CdTe QDs and AuNPs, with dual signal amplified by reduced graphene oxide and AuNPs was proposed for the sensitive detection of prostate specific antigen(PSA). Through a sandwich immunoreaction, the target PSA and AuNPs@GSH-CdTe labeled Ab1 were captured to rGO/AuNPs-Ab2 surface. After the HNO3-dissolution step, square wave stripping voltammetry(SWSV)analysis of the captured CdTe QDs was used to quantify the concentration of PSA. In this system, AuNPs possessedlarge specific surface and good biocompatibility, which could effectively expand the amount of antigen and GSH-CdTe QDs loading and signals amplifying, while rGO played a synergistic amplification role due to its large specific surface. The proposed method showed good linearity ranging from 0. 5 to 200 ng/mL with the detection limits of 5. 0 pg/mL. It also showed excellent selectivity, good reproducibility, satisfactory stability. In addition, the method was successfully applied to the determination of real samples. The result was satisfactory and the recovery could fall in 98. 20%- 106. 2%, which represented a novel approach for versatile detection of tumor markers.
ABSTRACT
OBJECTIVE To elucidate the toxicological properties of CdTe quantum dots (CdTe QD) by investigating their effect on mitophagy in human umbilical vein endothelial cells (HUVECs).METHODS The purity of primarily cultured HUVECs was detected by immunofluorescence.Then,HUVECs were incubated with CdTe QD 0.1-100 mg· L-1 for 24 h.After treatment,the cell viability of HUVECs was detected with MT-T assay.The mitochondrial morphology was observed under a laser scanning confocal microscope after labeling with Mitotracker.The treated HUVECs were also labeled with JC-1 probe,and the mitochondrial membrane potential (MMP) was then examined by flow cytometry.The expression of mitophagy-related proteins including microtubule-associated protein 1 light chain 3 Ⅰ /Ⅱ (LC3 Ⅰ /Ⅱ),moesin-like BCL2-induced protein1(Beclin1),phosphatase and tensin (PTEN) homologinduced putative kinase 1(PINK1) and dynamin-related protein Ⅰ (DRP1) was determined by Westem blotting.RESULTS More than 95％ of the cultured cells expressed vascular endothelial cadherin and herein were vascular endothelial cells.The MTT result showed that the cell survival of HUVECs was significantly decreased after incubation with CdTe QD (0.1-100 mg,L-1) for 24 h (P＜0.05,P＜0.01).CdTe QD also induced extensive fragmentation of the mitochondrial network.The results of JC-1 assay showed that CdTe QD (0.1-100 mg· L-1) caused the disruption of MMP.The percentage of HUVECs with higher MMP was reduced from (91.8±0.6)％ in cell control group to (90.2±1.1)％,(84.4±0.9)％ (P＜0.05) and (78.1 ±1.3)％ (P＜0.01),respectively.The Western blotting data suggested that CdTe QD 10 mg·L-1 significantly increased the expression of autophagy-related protein beclin 1 and the ratio of LC3 Ⅱ/LC3 Ⅰ (P＜0.05,P＜0.01),CdTe QD 1 mg· L-1 also raised the level of mitophagy-related proteins like PINK1 and DRP1.CONCULSION CdTe QD can induce mitochondrial dysfunction as well as mitophagy in HUVECs.
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The water-soluble 3-mercaptopropionic acid (MPA)-stabilized CdTe (MPA-CdTe) quantum dots (QDs) were synthesized by aqueous suspension.The study showed that the fluorescence quenching process of Cu2+ to MPA-CdTe QDs,whose largest emission peak was 599 nm,could be described well by the theory of fluorescence quenching in competitive absorption systems and its modification of Stern-Volmer equations.By fittings,the results showed a good polynomial relationship between the fluorescence intensity F0/F and the concentration of Cu2+,when the concentration was in the range of 2.28 × 10-6-18.24 × 10-6 mol/L and 4.8 × 10-7-12 × 10-7 mol/L,and two polynomial equations were respectively elucidated based on dynamic and static quenching in competitive-absorption systems:F0/F =7.999-2.470c +0.339 c2,F0/F =3.154-0.160 c +0.049 c2 and degree of fitting are 0.991 and 0.993,respectively.The detection limit was 1.326 × 10-7.
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The nanocomposites of poly-diallyldimethylammonium chloride (PDADMAC) and CdTe quantum dots (QDs) (i.e.QDs-PDADMAC nanocomposites) have been prepared based on electrostatic interaction and their fluorescence stability in aqueous solution has been investigated. MTT method(3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide method) was used to study their cytotoxicity and A549 lung cancer cell as a model cell was also used to evaluate their cellular imaging.It was shown that the fluorescence stability of QDs-PDADMAC nanocomposites was much better than that of bare QDs both in aqueous solution and cell.Meanwhile,QDs-PDADMAC nanocomposites display very low cytotoxicity in the low concentrations and better staining ability compared with QDs.QDs-PDADMAC nanocomposites will have great advantage on the cell analysis detection and imaging.
ABSTRACT
Semiconductor nanoparticles, such as quantum dots (QDs), were used to carry out experiments in vivo and ex vivo with Trypanosoma cruzi. However, questions have been raised regarding the nanotoxicity of QDs in living cells, microorganisms, tissues and whole animals. The objective of this paper was to conduct a QD nanotoxicity study on living T. cruzi protozoa using analytical methods. This was accomplished using in vitro experiments to test the interference of the QDs on parasite development, morphology and viability. Our results show that after 72 h, a 200 μM cadmium telluride (CdTe) QD solution induced important morphological alterations in T. cruzi, such as DNA damage, plasma membrane blebbing and mitochondrial swelling. Flow cytometry assays showed no damage to the plasma membrane when incubated with 200 μM CdTe QDs for up to 72 h (propidium iodide cells), giving no evidence of classical necrosis. Parasites incubated with 2 μM CdTe QDs still proliferated after seven days. In summary, a low concentration of CdTe QDs (2 μM) is optimal for bioimaging, whereas a high concentration (200 μM CdTe) could be toxic to cells. Taken together, our data indicate that 2 μM QD can be used for the successful long-term study of the parasite-vector interaction in real time.