牛血清白蛋白修饰的近红外荧光纳米金顺磁标记分子探针

摘要

Bovine serum albumin ( BSA) -modified spin-labeled near-infrared fluorescence gold nanoparticles as bimodal molecular probe was designed and synthesized. Glutathione capped gold nanoparticles ( GSH-AuNPs) was synthesized and modified by BSA, the BSA modified fluorescent gold nanoparticles conjugates (GSH-AuNPs@ BSA) was spin-labeled by paramagnetic nitroxide radical and gave a spin-labeled conjugate GSH-AuNPs@ BSA-TEMPO. The introduction of BSA to the conjugate was to further modify the surface of GSH-AuNPs in order to enhance the intrinsic fluorescence of GSH-AuNPs, and to facilitate the spin labeling. GSH-AuNPs@ BSA-TEMPO itself was a weak fluorescent conjugate and showed strong ESR signal properties. Reducing the paramagnetic functional group TEMPO in the as-prepared conjugates to its counterpart hydroxyla-mine by ascorbic acid, both Off-on fluorescence increase and On-off ESR decrease are observed, showing concentration related bimodal response to ascorbic acid(AA).%以光稳定性良好、Stokes位移大且可近红外发射的谷胱甘肽包裹纳米金(GSH-AuNPs)为发光载体,以4-氨基-2,2,6,6-四甲基哌啶氮氧自由基(4-NH2-TEMPO)作为顺磁标记基团,对构建发光-顺磁双模式传感分子探针进行了研究；以牛血清白蛋白(BSA)为表面修饰剂,通过调节荧光纳米金的表面状态,改善顺磁标记微环境,获得了基于顺磁基团识别诱导信号传导的荧光-顺磁双模式响应型分子探针.顺磁标记BSA修饰GSH-AuNPs形成弱荧光-强顺磁复合物(GSH-AuNPs@BSA-TEMPO),复合物中顺磁基团TEMPO经抗坏血酸还原后呈现出荧光增强和顺磁信号减弱现象,表现出对抗坏血酸浓度相关的荧光Off-on与顺磁On-off的双模式响应.