ZnO quantum dots a novel nanomaterial for various applications: Recent advances and challenges

Globally, in the recent era of 22nd century, ZnO quantum dots has gained huge attention of researchers towards its various applications in nano-biotechnology industry. This review article provides substantial approach on several aspects of ZnO quantum dots, its properties, synthesis process, factors affecting the synthesis process. Recent advances and challenges in QDs synthesis and their applications. Though the use of ZnO QDs has shown huge progress, but still so many challenges are there at present like economically cheaper level commercialization of quantum dots, proper in vitro and in vivo application of ZnO quantum dots, so that it can fulfil the need of the industry for various applications.

A hybrid bacterium with tumor-associated macrophage polarization for enhanced photothermal-immunotherapy

Remodeling the tumor microenvironment through reprogramming tumor-associated macrophages (TAMs) and increasing the immunogenicity of tumors via immunogenic cell death (ICD) have been emerging as promising anticancer immunotherapy strategies. However, the heterogeneous distribution of TAMs in tumor tissues and the heterogeneity of the tumor cells make the immune activation challenging. To overcome these dilemmas, a hybrid bacterium with tumor targeting and penetration, TAM polarization, and photothermal conversion capabilities is developed for improving antitumor immunotherapy in vivo. The hybrid bacteria (B.b@QDs) are prepared by loading Ag2S quantum dots (QDs) on the Bifidobacterium bifidum (B.b) through electrostatic interactions. The hybrid bacteria with hypoxia targeting ability can effectively accumulate and penetrate the tumor tissues, enabling the B.b to fully contact with the TAMs and mediate their polarization toward M1 phenotype to reverse the immunosuppressive tumor microenvironment. It also enables to overcome the intratumoral heterogeneity and obtain abundant tumor-associated antigens by coupling tumor penetration of the B.b with photothermal effect of the QDs, resulting in an enhanced immune effect. This strategy that combines B.b-triggered TAM polarization and QD-induced ICD achieved a remarkable inhibition of tumor growth in orthotopic breast cancer.

Gold nanorods-mediated efficient synergistic immunotherapy for detection and inhibition of postoperative tumor recurrence

Tumor recurrence after surgery is the main cause of treatment failure. However, the initial stage of recurrence is not easy to detect, and it is difficult to cure in the late stage. In order to improve the life quality of postoperative patients, an efficient synergistic immunotherapy was developed to achieve early diagnosis and treatment of post-surgical tumor recurrence, simultaneously. In this paper, two kinds of theranostic agents based on gold nanorods (AuNRs) platform were prepared. AuNRs and quantum dots (QDs) in one agent was used for the detection of carcinoembryonic antigen (CEA), using fluorescence resonance energy transfer (FRET) technology to indicate the occurrence of

Biological Application of Folate-Targeted Fluorescent Quantum Dots Liposome Nanoprobes / 中国药学杂志

OBJECTIVE: To illustrate and evaluate the properties of folate-targeted liposomes loaded with quantum dots (folate- QDs-liposomes) nanoprobes in vitro and in vivo, such as cytotoxicity, the targeting of folate-QDs-liposomes nanoprobes for tumor cells mediated by the folate-folate receptor pathway, their toxicity in vivo and so on. METHODS: Firstly, the inhibitory effects of folate- QDs-liposomes on cell growth and apoptosis were investigated by MTT and flow cytometry. Secondly, the targeting of folate-QDs-liposomes for folate receptor-positive tumor cells was verified by fluorescence staining. Finally, the epidermal infiltration method was adopted to examine the toxicity and distribution in vivo. RESULTS: Under the same concentration, folate-QDs-liposomes and QDs-liposomes had similar cytotoxicity, and QDs had the most obvious cytotoxicity, which verified that the cytotoxicity of QDs was significantly reduced after liposome coating. In the fluorescence experiment, it was observed that folate-QDs-liposomes targeted at Hela cells, but did not target at A549 cells. Free folic acid could block the specific binding of folate-QDs-liposomes to folate receptors on tumor cells. It was proved that folate-QDs-liposomes could enter tumor cells positively expressing folate receptors through the path of folic acid and folate receptors. In vivo, folate-QDs-liposomes nanoprobes could spread throughout the zebrafish body through the blood circulation system. They were distributed from head and excreted from the tails. CONCLUSION: Folate-QDs-liposomes have potential biomedical application prospects, and can be expected to play an important role in the early detection and diagnosis of tumors.

Co-expression of p53 and EGFR in colorectal cancer detected by quantum dots fluorescence probe / 国际检验医学杂志

Objective Simultaneous detection of two tumor markers p53 and EGFR in colorectal cancer samples.Methods Co-expression of p53 and EGFR in colorectal cancer detected by QDs fluorescence probe. TNM staging,grade and other factors were analyzed.Results The strong positive rate of p53 in colorectal cancer was 48.6%.It was significantly correlated with the N staging(P<0.05),the positive rate of EGFR and p53 in colorectal carcinoma was 67.1%.It was significantly correlated with the N staging(P<0.05),and was independent of other factors(P>0.05).Conclusion The method of QDs is helpful to quantitative analy-sis of co expression of p53 and EGFR in colorectal cancer,and it can provide the basis for clinical prognosis of colorectal cancer.

Oxidative damage effects induced by CdTe quantum dots in mice / 中华劳动卫生职业病杂志

Objective@#To investigate Oxidative damage effects induced by CdTe Quantum Dots (QDs) in mice.@*Methods@#40 ICR mice were randomly divided into 5 groups: one control group (normal saline) ; four CdTe QDs (exposed by intravenous injection of 0.2 ml of CdTe QDs at the concentration of 0、0.5、5.0、50.0 and 500.0 nmol/ml respectively) . After 24 h, the mice were decapitated and the blood was collected for serum biochemically indexes、hematology indexes, the activities of SOD、GSH-Px and the concentration of MDA were all detected.@*Results@#The results showed in the four CdTe QDs exposure groups, the level of CRE、PLT and the concentration of MDA were all significantly lower than those of the control group (P<0.05 or P<0.01) ; the activities GSH-Px in 50.0 and 500.0 nmol/ml CdTe QDs group were significantly higher than those of control group (P<0.01) .@*Conclusion@#It was suggested that CdTe QDs at 0.5 nmol/ml could induce Oxidative damage effects in mice.

Development of sandwich-form biosensor to detect Mycobacterium tuberculosis complex in clinical sputum specimens

Mycobacterium tuberculosis, the causing agent of tuberculosis, comes second only after HIV on the list of infectious agents slaughtering many worldwide. Due to the limitations behind the conventional detection methods, it is therefore critical to develop new sensitive sensing systems capable of quick detection of the infectious agent. In the present study, the surface modified cadmium-telluride quantum dots and gold nanoparticles conjunct with two specific oligonucleotides against early secretory antigenic target 6 were used to develop a sandwich-form fluorescence resonance energy transfer-based biosensor to detect M. tuberculosis complex and differentiate M. tuberculosis and M. bovis Bacille Calmette–Guerin simultaneously. The sensitivity and specificity of the newly developed biosensor were 94.2% and 86.6%, respectively, while the sensitivity and specificity of polymerase chain reaction and nested polymerase chain reaction were considerably lower, 74.2%, 73.3% and 82.8%, 80%, respectively. The detection limits of the sandwich-form fluorescence resonance energy transfer-based biosensor were far lower (10 fg) than those of the polymerase chain reaction and nested polymerase chain reaction (100 fg). Although the cost of the developed nanobiosensor was slightly higher than those of the polymerase chain reaction-based techniques, its unique advantages in terms of turnaround time, higher sensitivity and specificity, as well as a 10-fold lower detection limit would clearly recommend this test as a more appropriate and cost-effective tool for large scale operations.

Selective Effects of Curcumin on CdSe/ZnS Quantum-dot-induced Phototoxicity Using UVA Irradiation in Normal Human Lymphocytes and Leukemia Cells

Quantum dots (QDs) have received considerable attention due to their potential role in photosensitization during photodynamic therapy. Although QDS are attractive nanomaterials due to their novel and unique physicochemical properties, concerns about their toxicity remain. We suggest a combination strategy, CdSe/ZnS QDs together with curcumin, a natural yellow pigment from turmeric, to reduce QD-induced cytotoxicity. The aim of this study was to explore a potentially effective cancer treatment: co-exposure of HL-60 cells and human normal lymphocytes to CdSe/ZnS QDs and curcumin. Cell viability, apoptosis, reactive oxygen species (ROS) generation, and DNA damage induced by QDs and/or curcumin with or without ultraviolet A (UVA) irradiation were evaluated in both HL-60 cells and normal lymphocytes. In HL-60 cells, cell death, apoptosis, ROS generation, and single/double DNA strand breaks induced by QDs were enhanced by treatment with curcumin and UVA irradiation. The protective effects of curcumin on cell viability, apoptosis, and ROS generation were observed in normal lymphocytes, but not leukemia cells. These results demonstrated that treatment with QD combined with curcumin increased cell death in HL-60 cells, which was mediated by ROS generation. However, curcumin acted as an antioxidant in cultured human normal lymphocytes.

The photological function of MPA coated CdTe QDs and their biocompatibility / 细胞与分子免疫学杂志

AIM: To investigate the CdTe quantum dots coated with MPA and explore its biocompatibility with living cells. METHODS: CdTe quantum dots coated with MPA were prepared in aqueous phase and MPA CdTe QDs were Characterized with TEM, fluorospectrophotometer and ultraviolet spectrophotometer. QDs were Modified with with avidin, purified and prepared as flurescent probe. LSCM was used to observe the expression of MHC Ⅱ antigen on PMφ cells, which was labeled by QDs. Cell culture and MTT assays were used to determine the biocompatibility of MPA coated CdTe quantum dots with the B-16 cells as target cells. RESULTS: The particle diameter of CdTe quantum dots prepared in aqueous phase was well distributed. They had good photological performance and greater stability after coated with MPA. MHC Ⅱ antigen on PMφ was labeled with the QDs-Avidin fluorescent probe showed great fluorescence intensity, which was easy to be detected by fluorescence microscope and LSCM. MPA CdTe QDs showed cytotoxicity when its density was very high, but they showed little cytotoxicity during the normal use of influence label density limit. CONCLUSION: MPA CdTe QDs can be used as new fluorescent lable as they are of even size, not easy to bleach or quench, have good photological performance and stability and good biocompatibility.