Objective To explore the cytotoxicity, labeled time, marking rate, and effect on adhesion of quantum dot 655 (QD655) labeled rat bone marrow mesenchymal stem cells (BMSCs) in vitro, and to confirm its feasibil ity for stem cell label ing and tracer means for rat. Methods BMSCs were collected from the femur and tibia bone marrow cavity of a 2-week-old SD rat, cultured and identified. The 3rd passage of BMSCs were incubated with QD655 as the experimental groupaccording to the recommended concentration of the markers. The cells were not labeled by QD655 as control group. Thecell survival rate after QD655 label ing was detected by trypan-blue exclusion. The effect of QD655 on cell prol iferation was observed by MTT. The osteogenic differentiation potential was identified by Al izarin red staining, alkal ine phosphatase (ALP) staining, and real-time fluorogenic quantitative PCR. At immediately, 1, 2, 4, and 6 weeks, fluorescent microscopy was used to observe the labeled rate and scanning electron microscope was used to observe the cell adhesion to scaffold (bioglass/collagen composite). Results The cell survival rates were more than 90% in both experimental group and control group, showing no significant difference (P gt; 0.05). There was no significant difference in the cell prol iferation between 2 groups (P gt; 0.05). Al izarin red staining and ALP staining showed positive results. Real-time fluorogenic quantitative PCR result showed that the mRNA expression levels of osteopontin, osteocalcin, collagen type I, ALP, and BMP-2 in the experimental group was significantly higher than those in the control group. The labeled rates were 96.50% ± 1.59%, 93.30% ± 1.51%, 72.40% ± 2.90%, 40.10% ± 3.60%, and 10.00% ± 1.70% immediately, 1, 2, 4, and 6 weeks after label ing, respectively. The labeled rate in the control group was 0. Scanning electron microscope showed a good distribution of fusiform or polygonal cells in the pores of scaffold. Conclusion QD655 can be used as a label ing marker for BMSCs. Rat BMSCs labeled with QD655 is of high efficiency and safety.
With the continuous development of modern laboratory medicine, the intersection of laboratory medicine and multi-disciplines such as chemistry, physics, and biology has become an inevitable trend, and received extremely extensive attention. As a new nanomaterial with great application prospect in the field of chemistry, quantum dots have brought a new idea for medical laboratory research. This paper summarizes the research status and progress of quantum dots in the diagnosis of infectious diseases, tumors and other diseases. The advantages and disadvantages of existing detection techniques based on quantum dots are discussed in order to provide theoretical thinking for the application of this nanomaterials in laboratory medicine in the future.
Near-infrared fluorescence imaging technology, which possesses superior advantages including real-time and fast imaging, high spatial and temporal resolution, and deep tissue penetration, shows great potential for tumor imaging in vivo and therapy. Ⅰ-Ⅲ-Ⅵ quantum dots exhibit high brightness, broad excitation, easily tunable emission wavelength and superior stability, and do not contain highly toxic heavy metal elements such as cadmium or lead. These advantages make Ⅰ-Ⅲ-Ⅵ quantum dots attract widespread attention in biomedical field. This review summarizes the recent advances in the controlled synthesis of Ⅰ-Ⅲ-Ⅵ quantum dots and their applications in tumor imaging in vivo and therapy. Firstly, the organic-phase and aqueous-phase synthesis of Ⅰ-Ⅲ-Ⅵ quantum dots as well as the strategies for regulating the near-infrared photoluminescence are briefly introduced; secondly, representative biomedical applications of near-infrared-emitting cadmium-free quantum dots including early diagnosis of tumor, lymphatic imaging, drug delivery, photothermal and photodynamic therapy are emphatically discussed; lastly, perspectives on the future directions of developing quantum dots for biomedical application and the faced challenges are discussed. This paper may provide guidance and reference for further research and clinical translation of cadmium-free quantum dots in tumor diagnosis and treatment.