Facile Synthesis And Biological Effects Of Silver Chalcogenide Quantum Dots

During the past decade,with the rapid development of nanomaterials,nanometer quantum dots have shown more and more broad application prospects in many aspects of biomedical field,such as the diagnosis and treatment of tumor and labeling and detection of proteions,which have aroused scientists' great research interest.Many studies have investigated colloidal silver chalcogenide quantum dots due to their special properties,for instance,high photostability,high colloidal stability,low cost,and so on.However,colloidal silver chalcogenide quantum dots prepared in organic phases were usually water-insoluble,requiring tedious synthetic procedures,harsh reaction conditions,and post-treatments that entail ligand exchange.Because most biomedical applications occur in the aqueous media,the synthesis of stable water-soluble QDs is of great importance.Therefore,it is a challenge to develop a facile and aqueous synthesis method to prepare water-soluble silver chalcogenide quantum dots.On the other hand,metal sulfide nanoparticles have also been widely applied in the fields of solar cell,lithium ion battery,optical material and magnetic material.Before any metal sulfide nanoparticle can be adopted for practical use,its Environmental Health and Safety(EHS)profile must be determined.But,little is known about the safety of these nanoparticles to humans and to the environment at present.In this article,using BSA as organic matrix,Ag2 S QDs,Ag2 Se QDs,and Ag2 Te QDs were prepared in aqueous phase through a facile and controllable biomimetic synthetic method.The cytotoxicities as well as the potential applications in cell imaging and protein detection of the as-prepared QDs were investigated.What's more,the nature of the cytotoxicities was explored preliminarily.The main research contexts are as follows:(1)BSA-Ag2 S QDs were prepared through a facile approach and their cytotoxicities were investigated.In the meantime,the nature of the cytotoxicities was explored preliminarily.Using BSA as matrix,BSA-Ag2 S QDs were prepared through facile aqueous synthesis.They were characterized by XRD,HRTEM,Zeta potential,CLSM,and the like.The results indicated that water-soluble ?-monoclinic Ag2 S with an average size of 9.40 nm was obtained.The zeta potential of the Ag2 S QDs hydrosol is-22.1 mV,indicating the relative stability of Ag2 S QDs in neutral deionized water.Additionally,stable green fluorescence was observed when dispersed into neutral deionized water.Further research showed that Ag2 S QDs were cytotoxic and they could specifically inhibit the proliferation of HeLa cells,HepG2 cells and A549 cells in a concentration-dependent manner.The IC50 values for HeLa cells,HepG2 cells and A549 cells are 3.92,4.57 and 16.10 ?g/mL,respectively.Using fluorescence labeling test and inductively coupled plasma–mass spectroscopy(ICP-MS),the uptakes of Ag2 S QDs by cells were determined.In addition,the speculation on the difference of the uptakes was confirmed.Flow cytometry result revealed that Ag2 S QDs could inhibit the proliferation of cancer cells by inducing the necrosis of cancer cells.(2)BSA-Ag2 Se QDs were prepared through a facile approach and their potential applications in cell imaging and protein detection were investigated.Using BSA as matrix,BSA-Ag2 Se QDs were prepared through facile aqueous synthesis.They were characterized by XRD,HRTEM,Zeta potential,CLSM,and the like.The results indicated that water-soluble orthorhombic ?-Ag2 Se with an average size of 4.04 nm was obtained.The zeta potential of the Ag2 Se QDs hydrosol is-30.3 mV,indicating the good stability of Ag2 Se QDs in neutral deionized water.The emission peaks of Ag2 Se QDs appear at 485 nm and 527 nm.Additionally,stable green fluorescence was observed when dispersed into neutral deionized water.Using the cytotoxicity experiment and inductively coupled plasma–mass spectroscopy(ICP-MS),the excellent biocompatibility and the specifically internalization of Ag2 Se QDs by cancer cells were determined.Moreover,fluorescence labeling test results suggested that Ag2 Se QDs could be used as fluorescent probe for the specific fluorescence imaging of cancer cells.Results of protein detection proved that Ag2 Se QDs could be used roughly for the quantitative determination of BSA and HSA V.(3)BSA-Ag2 Te QDs were prepared through a facile approach and their cytotoxicities were investigated.In the meantime,the nature of the cytotoxicities was explored preliminarily.Using BSA as matrix,BSA-Ag2 Te QDs were prepared through facile aqueous synthesis.They were characterized by XRD,HRTEM,Zeta potential,CLSM,and the like.The results indicated that water-soluble monoclinic Ag2 Te with an average size of 5.30 nm was obtained.The zeta potential of the Ag2 Te QDs hydrosol is-18.4 mV,indicating the relative stability of Ag2 Te QDs in neutral deionized water.Additionally,stable green fluorescence was observed when dispersed into neutral deionized water.Further research showed that Ag2 Te QDs were cytotoxic and they could specifically inhibit the proliferation of HeLa cells rather than V79-4 cells and HepG2 cells.Using fluorescence labeling test and inductively coupled plasma–mass spectroscopy(ICP-MS),the uptakes of Ag2 Te QDs by cells were determined.In addition,the speculation on the difference of the uptakes was confirmed.