Díaz Sebastián A, Gillanders Florencia, Susumu Kimihiro, Oh Eunkeu, Medintz Igor L, Jovin Thomas M
Center for Bio/Molecular Science and Engineering, Code 6900, U.S. Naval Research Laboratory, Washington, DC, 20375, USA.
Center for Investigation in Bionanosciences (CIBION-CONICET), Buenos Aires, Argentina.
Chemistry. 2017 Jan 5;23(2):263-267. doi: 10.1002/chem.201604688. Epub 2016 Nov 3.
Photoswitchable probes are of great utility in fluorescence microscopy, permitting numerous determinations, including molecular localization for super-resolution, based on their modifiable emission intensity and spectra. We have coated a blue-emitting (425 nm) quantum dot (QD) with a diheteroarylethene photochrome (PCf), the closed form isomer of which has absorption and emission maxima at 440 and 520-530 nm, respectively, and thus functions as a fluorescent acceptor for the QD donor in Förster resonance energy transfer (FRET). The transition from the non-absorbing, non-fluorescent open state to the fluorescent closed state is achieved by irradiation in the near-UV and reversed by visible light. The PCf is coupled to an amphiphilic polymer that stably coats the QD, thereby creating a water-soluble color-switching QD (csQD) emitting in the blue after visible light irradiation and in the green after UV irradiation. Thus, csQDs photomodulate between two observable states, without the "off" state of previous constructs. The resulting change in the emission ratios of the QD and PCf is up to 180 %, and the csQD can undergo multiple photocycles with minimal fatigue.
光开关探针在荧光显微镜中具有很大的用途，基于其可调节的发射强度和光谱，可进行多种测定，包括用于超分辨率的分子定位。我们用二芳基乙烯光致变色染料（PCf）包覆了一个发射蓝光（425nm）的量子点（QD），其闭环异构体在440nm和520 - 530nm处分别具有吸收和发射最大值，因此在Förster共振能量转移（FRET）中作为QD供体的荧光受体。从非吸收、非荧光的开放态到荧光闭环态的转变通过近紫外光照射实现，而可见光可使其逆转。PCf与一种两亲性聚合物相连，该聚合物稳定地包覆QD，从而产生一种水溶性颜色转换量子点（csQD），在可见光照射后发射蓝光，在紫外光照射后发射绿光。因此，csQD在两种可观察状态之间进行光调制，没有先前构建体的“关闭”状态。QD和PCf发射比率的最终变化高达180%，并且csQD可以经历多次光循环且疲劳最小。
