"Turn-on" phosphorescent nanoprobes for sensing homocysteine and cysteine

In this work, we designed and fabricated a series of new nanoprobes by using the high specific surface area and good biocompatibility of mesoporous silica nanoparticles as a probe carrier and the long lifetime luminescence of phosphorescent complexes as signal unit. The structures and physical properties of prepared nanoprobes were characterized by SEM, TEM, XRD and nitrogen adsorption/desorption isotherms. Spectrophotometry determination was performed in phosphate buffer saline (PBS) buffer for Hcy/Cys sensing. To further understand the response mechanism, the effect of the aldehyde (CHO) group on the photophysical properties was calculated by using TDDFT calculation method. The result demonstrated that the as-prepared nanoprobe exhibited high selectivity for Hcy and Cys in pure PBS, which provides the advantage in developing excellent phosphorescent cellular probes for practical applications.