Li Jin-Gui, Zhu Kui, Xu Fei, Jiang Hai-Yang, Ding Shuang-Yang
College of Veterinary Medicine of Yangzhou University, Yangzhou 225009, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2009 Nov;29(11):3070-4.
The water-soluble CdTe quantum dots (QDs) were prepared by using mercaptopropionic acid (MPA) as stabilizer in the aqueous system. Fluorescence resonance energy transfer (FRET) system was constructed between gentamycin (acceptor) and water-soluble CdTe QDs (donor). The maximal emission wavelength was 690 nm, and the line width of the fluorescence spectrum was very narrow (with the full width at half-maximum about 10 nm) and symmetric. The transfer of resonance energy from the CdTe QDs to gentamycin (GT) resulted in the fluorescence quenching of the QDs, corresponding to the increase in the concentration of GT. Several factors that impacted the fluorescence spectra of the FRET system, such as the excitation wavelength (305-425 nm), pH(5.0-11.0), ions (0-0.1 mmol x L(-1) PBS; 0-0.5 mmol x L(-1) NaCl), time (1-120 min), temperature (5-50 degrees C), and concentration of GT (2-80 mg x L(-1)), were investigated and refined. The linear ranges of GT concentration were 2-20 mg x L(-1), r = 0.986 7. Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC) were used for confirming the chemical construction and relative specificity, respectively. The results indicated that sulfur and oxygen atoms in MPA molecules took part in coordination with rich Cd2+ on the surface of the nanoparticles. Meanwhile the results also demonstrated that the hydrogen bond between carboxyl of mercaptopropionic acid on the surface of quantum dots and amidocyanogen of GT mainly contributes to combining CdTe with GT. The combination ratio between GT and CdTe QDs is 0.35 to 1.0 according to HPLC. GT as an enhancement has first been applied to the determination of the bovine serum albumin (BSA) labeled with CdTe QDs, and the fluorescence intensity of the labeled BSA with GT is 6 times higher than the control. The proposed method might offer an attractive potential for use in future, because it is sensitive and rapid.
在水相中以巯基丙酸（MPA）为稳定剂制备了水溶性碲化镉量子点（QDs）。构建了庆大霉素（受体）与水溶性碲化镉量子点（供体）之间的荧光共振能量转移（FRET）体系。其最大发射波长为690 nm，荧光光谱的线宽非常窄（半高宽约为10 nm）且呈对称分布。共振能量从碲化镉量子点转移至庆大霉素（GT）导致量子点荧光猝灭，这与GT浓度的增加相对应。研究并优化了影响FRET体系荧光光谱的几个因素，如激发波长（305 - 425 nm）、pH值（5.0 - 11.0）、离子（0 - 0.1 mmol·L⁻¹ PBS；0 - 0.5 mmol·L⁻¹ NaCl）、时间（1 - 120 min）、温度（5 - 50℃）以及GT浓度（2 - 80 mg·L⁻¹）。GT浓度的线性范围为2 - 20 mg·L⁻¹，r = 0.986 7。分别使用傅里叶变换红外光谱（FTIR）和高效液相色谱（HPLC）来确认化学结构和相对特异性。结果表明，MPA分子中的硫和氧原子参与了与纳米颗粒表面丰富的Cd²⁺的配位。同时结果还表明，量子点表面巯基丙酸的羧基与GT的氨基之间的氢键主要促成了CdTe与GT的结合。根据HPLC，GT与CdTe量子点的结合比为0.35比1.0。GT作为增强剂首次应用于测定标记有CdTe量子点的牛血清白蛋白（BSA），用GT标记的BSA的荧光强度比对照高6倍。所提出的方法可能具有吸引人的潜在应用前景，因为它灵敏且快速。
