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Quantum dots as fluorescent stains in confocal scanning laser microscopy studies of Vigna radiata seedlings
Author
Lau, Hoay Min
Supervisor
Kwek, Leong Chuan
Abstract
Quantum dots (QDs) are nanocrystalline fluorophores which are widely used in fluorescent bioimaging applications. In this report, two types of QDs were used. A commercially prepared QD, CdSe core with a ZnS shell, was dissolved in chloroform, a nonpolar hydrophobic solvent. It was not solubilized, whereas the other QD used, TiO2 , was in the form of a water soluble nanogel.
Comparison of the effects of the two types of QDs on mung bean ( Vigna radiata ) seedlings yielded different observations. Cross-sections of the root and shoot of the seedlings under the confocal scanning laser microscope showed no significant uptake of the CdSe/ZnS QDs ( when the liquid was not used in excess ), an expected result since the solution in chloroform was non-biocompatible. However, a simple and fast method of photostable fluorescent staining of cell nuclei was obtained by an in vitro immersion of the sample with CdSe/ZnS QDs in chloroform. This method could not be used in the case of a water-soluble gel like TiO2.
For the TiO2 sol-gel, in vivo fluorescent imaging of cross-sections of the root and shoot of the seedlings showed a significant uptake in the regions of the epidermis and vascular cylinder. However, the laboratory produced TiO2 was not as brightly fluorescent as the CdSe/ZnS QDs in the excitation and emission ranges used. The studies also yielded observational foot-notes regarding the toxicity of the two types of QDs and the effects, if any, on the mung bean seedlings.
Comparison of the effects of the two types of QDs on mung bean ( Vigna radiata ) seedlings yielded different observations. Cross-sections of the root and shoot of the seedlings under the confocal scanning laser microscope showed no significant uptake of the CdSe/ZnS QDs ( when the liquid was not used in excess ), an expected result since the solution in chloroform was non-biocompatible. However, a simple and fast method of photostable fluorescent staining of cell nuclei was obtained by an in vitro immersion of the sample with CdSe/ZnS QDs in chloroform. This method could not be used in the case of a water-soluble gel like TiO2.
For the TiO2 sol-gel, in vivo fluorescent imaging of cross-sections of the root and shoot of the seedlings showed a significant uptake in the regions of the epidermis and vascular cylinder. However, the laboratory produced TiO2 was not as brightly fluorescent as the CdSe/ZnS QDs in the excitation and emission ranges used. The studies also yielded observational foot-notes regarding the toxicity of the two types of QDs and the effects, if any, on the mung bean seedlings.
Date Issued
2006
Call Number
QH324.9.B48 Lau
Date Submitted
2006