TY - JOUR
T1 - Synthesis of size-tunable photoluminescent aqueous CdSe/ZnS microspheres via a phase transfer method with amphiphilic oligomer and their application for detection of HCG antigen
AU - Zhou, Changhua
AU - Yuan, Hang
AU - Shen, Huaibin
AU - Guo, Yi
AU - Li, Xiaomin
AU - Liu, Dan
AU - Xu, Li
AU - Ma, Lan
AU - Li, Lin Song
PY - 2011/5/28
Y1 - 2011/5/28
N2 - High quality water-soluble photoluminescent (PL) microspheres consisting of CdSe/ZnS quantum dots (QDs) and amphiphilic oligomers (polymaleic acid n-hexadecanol ester) were prepared by a versatile phase transfer method in an emulsion system. Controlled synthesis of different sizes of PL microspheres can be conducted by simply changing the initial oligomer concentration and/or the water/chloroform volume ratio. When the oligomer/QDs molar ratio exceeded 200:1, only oligomer-coated monodisperse CdSe/ZnS QDs without any aggregation were obtained. If the molar ratio ranged from 20:1 to 120:1, size-tunable PL microspheres could be obtained with a size range from 151 to 50 nm. Both of them exhibited high stability in aqueous solution under a wide range of pH, different salt concentrations, and thermal treatment at 100 °C. FTIR spectroscopy, transmission electron microscopy, dynamic light scattering, and fluorescence microscopy were used to characterize the PL microspheres and oligomer-coated monodisperse QDs. It is demonstrated that the stability of PL microspheres indeed depended on their dimensions. Larger PL microspheres could provide more hydrophobic protection for their interior QDs than smaller PL microspheres. A biosensor system (lateral flow immunoassay system, LFIA) for the detection of human chorionic gonadotrophin (HCG) antigen was developed by using CdSe/ZnS PL microspheres as fluorescence labels and a nitrocellulose filter membrane for lateral flow. The result showed that the PL microspheres were excellent fluorescence labels to detect HCG antigen in this LFIA system. The sensitivity of HCG antigen detection can reach 0.5 IU L-1, which is almost 20 times higher than traditional LFIAs using tinctorial labels.
AB - High quality water-soluble photoluminescent (PL) microspheres consisting of CdSe/ZnS quantum dots (QDs) and amphiphilic oligomers (polymaleic acid n-hexadecanol ester) were prepared by a versatile phase transfer method in an emulsion system. Controlled synthesis of different sizes of PL microspheres can be conducted by simply changing the initial oligomer concentration and/or the water/chloroform volume ratio. When the oligomer/QDs molar ratio exceeded 200:1, only oligomer-coated monodisperse CdSe/ZnS QDs without any aggregation were obtained. If the molar ratio ranged from 20:1 to 120:1, size-tunable PL microspheres could be obtained with a size range from 151 to 50 nm. Both of them exhibited high stability in aqueous solution under a wide range of pH, different salt concentrations, and thermal treatment at 100 °C. FTIR spectroscopy, transmission electron microscopy, dynamic light scattering, and fluorescence microscopy were used to characterize the PL microspheres and oligomer-coated monodisperse QDs. It is demonstrated that the stability of PL microspheres indeed depended on their dimensions. Larger PL microspheres could provide more hydrophobic protection for their interior QDs than smaller PL microspheres. A biosensor system (lateral flow immunoassay system, LFIA) for the detection of human chorionic gonadotrophin (HCG) antigen was developed by using CdSe/ZnS PL microspheres as fluorescence labels and a nitrocellulose filter membrane for lateral flow. The result showed that the PL microspheres were excellent fluorescence labels to detect HCG antigen in this LFIA system. The sensitivity of HCG antigen detection can reach 0.5 IU L-1, which is almost 20 times higher than traditional LFIAs using tinctorial labels.
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U2 - 10.1039/c1jm10090d
DO - 10.1039/c1jm10090d
M3 - Article
AN - SCOPUS:79955589176
SN - 0959-9428
VL - 21
SP - 7393
EP - 7400
JO - Journal of Materials Chemistry
JF - Journal of Materials Chemistry
IS - 20
ER -