title: Two-photon excited quantum dots with compact surface coatings of polymer ligands used as an upconversion luminescent probe for dopamine detection in biological fluids.
abstract: Water-soluble multidentate polymer coated CdTe quantum dots (QDs) were prepared via a stepwise addition of raw materials in a one-pot aqueous solution under ambient conditions. Just by adjusting the compositions of raw materials, different sized CdTe QDs were achieved within a short time. The as-prepared QDs showed compact surface coating (1.6-1.8 nm) of polymer ligands and photoluminescence (PL) emitted at 533-567 nm, as well as high colloidal/photo-stability and quantum yields (58-67%). Moreover, these QDs exhibited significant upconversion luminescence (UCL) upon excitation using an 800 nm femtosecond laser. Experimental results confirm that the UCL was ascribed to the two-photon assisted process via a virtual energy state. Then, the two-photon excited QDs were further developed as a novel UCL probe of dopamine (DA) due to self-assembled binding of DA molecules with QDs via non-covalent bonding. As a receptor, the DA attached onto the QD surface induced an electron transfer from QDs to DA, triggering UCL quenching of QDs. This UCL probe of DA presented a low limit of detection (ca. 5.4 nM), and high selectivity and sensitivity in the presence of potential interferences. In particular, it was favorably applied to the detection of DA in biological fluids, with quantitative recoveries (96.0-102.6%).
authors: College of Chemical Science and Engineering, Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles of Shandong Province, Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, Laboratory of Fiber Materials and Modern Textiles, the Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071, PR China. guirijun@qdu.edu.cn wangzonghua@qdu.edu.cn.
authors: Hui
authors: H
authors: Jin
authors: Rijun
authors: R
authors: Gui
authors: Zonghua
authors: Z
authors: Wang
authors: Feifei
authors: F
authors: Zhang
authors: Jianfei
authors: J
authors: Xia
authors: Min
authors: M
authors: Yang
authors: Sai
authors: S
authors: Bi
authors: Yanzhi
authors: Y
authors: Xia
mesh_terms: D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry; D002417:Cattle; D004298:Dopamine / Q000097:blood* / Q000652:urine*; D015259:Dopamine Agents / Q000097:blood* / Q000652:urine*; D006801:Humans; D049408:Luminescent Agents / Q000737:chemistry*; D008163:Luminescent Measurements / Q000379:methods; D017785:Photons; D011108:Polymers / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D015259:Dopamine Agents; D049408:Luminescent Agents; D011108:Polymers; D013691:Tellurium; C028337:cadmium telluride; D004298:Dopamine