title: Interfacial synthesis of polyethyleneimine-protected copper nanoclusters: Size-dependent tunable photoluminescence, pH sensor and bioimaging.
abstract: The copper nanoclusters (CuNCs) offer excellent potential as functional biological probes due to their unique photoluminescence (PL) properties. Herein, CuNCs capped with hyperbranched polyethylenimine (PEI) were prepared by the interfacial etching approach. The resultant PEI-CuNCs exhibited good dispersion and strong fluorescence with high quantum yields (QYs, up to 7.5%), which would be endowed for bioimaging system. By changing the reaction temperatures from 25 to 150 °C, the size of PEI-CuNCs changed from 1.8 to 3.5 nm, and thus tunable PL were achieved, which was confirmed by transmission electron microscopy (TEM) imagings and PL spectra. Besides, PEI-CuNCs had smart absorption characteristics that the color changes from colorless to blue with changing the pH value from 2.0 to 13.2, and thus they could be used as color indicator for pH detection. In addition, the PEI-CuNCs exhibited good biocompatibility and low cytotoxicity to 293T cells through MTT assay. Owing to the positively charged of PEI-CuNCs surface, they had the ability to capture DNA, and the PEI-CuNCs/DNA complexes could get access to cells for efficient gene expression. Armed with these attractive properties, the synthesized PEI-CuNCs are quite promising in biological applications.
authors.affiliation: Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical & Material Engineering, Jiangnan University, Wuxi 214122, China.
authors.forename: Chan
authors.initials: C
authors.lastname: Wang
authors.affiliation: Division of Advanced Nanomaterials, Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Suzhou 215123, China. Electronic address: ygyao2013@sinano.ac.cn.
authors.forename: Yagang
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical & Material Engineering, Jiangnan University, Wuxi 214122, China. Electronic address: qsong@jiangnan.edu.cn.
authors.forename: Qijun
authors.initials: Q
authors.lastname: Song
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002725:Chloroform / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D005453:Fluorescence; D057809:HEK293 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D056951:Photoelectron Spectroscopy; D011094:Polyethyleneimine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D014867:Water; D003300:Copper; D002725:Chloroform; D011094:Polyethyleneimine
keywords: Bioimaging; Copper nanoclusters; Interfacial synthesis; Tunable photoluminescence; pH sensor