ABSTRACT
In comparison with traditional organic dyes, semiconductor quantum dots ( QDs) feature a series of superior luminescence properties, including narrow and symmetric emission, broad excitation and strong absorption, excellent photobleaching-resistance, and good water solubility. The addition of dopants can endows QDs with extra new properties, e. g. , further increase the Stokes shift for avoiding self-quenching. Mn-doped ZnS QDs are a very representative example of doped QDs. No harmful elements such as Cd and Hg are involved in such type of bio-friendly QDs. Besides, the Mn2+dopant further adds QDs with excellent room temperature phosphorescence. Phosphorescent detection can effectively eliminate the interference of biological background fluorescence, thus Mn-doped ZnS QDs can be widely used in phosphorescent bioanalysis. In this paper, the recent progress of room temperature phosphorescence analysis with Mn-doped ZnS QDs was reviewed. The emphasis was placed on the several stimulative sensing design strategies, including the luminescence mechanism, ion probes, detection of small molecules and biomacromolecules.
ABSTRACT
The key to maximize the sensitivity of inner filter effect ( IFE)-based assay is to enlarge the overlap between the absorption spectra of the absorber and the excitation or emission spectra of the fluorophore. In this work, Mn-doped ZnS quantum dots ( QDs) were chosen for IFE-based detection of β-glucuronidase ( GUS) , since the excitation of QDs was perfectly overlapped with the absorption of the substrate of GUS, namely 4-nitrophenyl-β-D-glucuronide ( PNPG) . In addition, the phosphorescence emission from Mn-doped ZnS QDs could eliminate the fluorescence background from biological samples. Therefore, a simple turn-on phosphorescent GUS assay was developed, with the linear range of 10-300 U/L and limit of detection of 7 U/L (S/N=3).
ABSTRACT
Objective To investigate the expression of VIT-1 gene in melanocytes of patients with vitiligo, and to analyze the difference of its sequence. Methods The skin from the foreskins of healthy men by circumcision and from the non-lesional area on the buttocks of 5 patients were digested by dispase, then the epidermis and dermis were separated, and the melanocytes were isolated. Then we cultured the melanocytes from the controls in TICVA medium and those from the patients in TICVA medium supplemented with basic fibroblast growth factor (bFGF) and endothelin-1 ( ET-1). The expression of VIT-1 gene was measured by RT-PCR, the full-length cDNA of VIT-1 ORF was cloned and sequenced, and sequence difference was analyzed by CLUSTAL W ( 1.83 ) software. Results The expression levels of VIT-1 gene were significantly lower in melanocytes from the patients than in those from the controls. An 81 bp-intron was found in the VIT-1 ORF. VIT-1 was a fragment of FBXO11, located at its 3' end. Conclusion VIT-1 gene is not a new gene, but a fragment of FBXO11, and a member of F-box protein family.