title: Facilitated preparation of bioconjugatable zwitterionic quantum dots using dual-lipid encapsulation.
abstract: Zwitterionic quantum dots prepared through incorporated zwitterionic ligands on quantum dot surfaces, are being paid significant attention in biomedical applications because of their excellent colloidal stability across a wide pH and ionic strength range, antifouling surface, good biocompatibility, etc. In this work, we report a dual-lipid encapsulation approach to prepare bioconjugatable zwitterionic quantum dots using amidosulfobetaine-16 lipids, dipalmitoyl-sn-glycero-3-phosphoethanolamine lipids with functional head groups, and CuInS2/ZnS quantum dots in a tetrahydrofuran/methanol/water solvent system with sonication. Amidosulfobetaine-16 is a zwitterionic lipid and dipalmitoyl-sn-glycero-3-phosphoethanolamine, with its functional head, provides bioconjugation capability. Under sonication, tetrahydrofuran/methanol containing amidosulfobetaine-16, dipalmitoyl-sn-glycero-3-phosphoethanolamine, and hydrophobic quantum dots are dispersed in water to form droplets. Highly water-soluble tetrahydrofuran/methanol in droplets is further displaced by water, which induces the lipid self-assembling on hydrophobic surface of quantum dots and thus forms water soluble zwitterionic quantum dots. The prepared zwitterionic quantum dots maintain colloidal stability in aqueous solutions with high salinity and over a wide pH range. They are also able to be conjugated with biomolecules for bioassay with minimal nonspecific binding.
authors.affiliation: Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA; Biomedical Engineering Program, University of Nevada, Reno, NV, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Shrake
authors.affiliation: Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA; Biomedical Engineering Program, University of Nevada, Reno, NV, USA.
authors.forename: Violeta G
authors.initials: VG
authors.lastname: Demillo
authors.affiliation: Department of Chemical and Materials Engineering, University of Nevada, Reno, NV, USA.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Ahmadiantehrani
authors.affiliation: Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA; Biomedical Engineering Program, University of Nevada, Reno, NV, USA. Electronic address: xzhu@unr.edu.
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA; Biomedical Engineering Program, University of Nevada, Reno, NV, USA; Department of Microbiology and Immunology, University of Nevada, Reno, NV, USA.
authors.forename: Nelson G
authors.initials: NG
authors.lastname: Publicover
authors.affiliation: Biomedical Engineering Program, University of Nevada, Reno, NV, USA; Department of Microbiology and Immunology, University of Nevada, Reno, NV, USA.
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Hunter
mesh_terms: D001672:Biocompatible Materials; D006863:Hydrogen-Ion Concentration; D008055:Lipids / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D009994:Osmolar Concentration; D045663:Quantum Dots; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D001672:Biocompatible Materials; D008055:Lipids
keywords: Bioconjugation; Colloidal stability; CuInS(2)/ZnS; Encapsulation; Lipids; Surface modification; Zwitterionic quantum dots