Facilitated preparation of bioconjugatable zwitterionic quantum dots using dual-lipid encapsulation

• Published in: Journal of colloid and interface science Vol. 437; pp. 140 - 146
• Main Authors: Shrake, Robert, Demillo, Violeta G., Ahmadiantehrani, Mojtaba, Zhu, Xiaoshan, Publicover, Nelson G., Hunter, Kenneth W.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2015
• Subjects: Biocompatible Materials; Bioconjugation; Colloidal stability; Colloids; CuInS2/ZnS; Droplets; Encapsulation; Hydrogen-Ion Concentration; Lipids; Lipids - chemistry; Methyl alcohol; Microscopy, Electron, Transmission; Osmolar Concentration; Quantum Dots; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Surface modification; Tetrahydrofuran; Zwitterionic quantum dots; Encapsulation; Surface modification; Colloidal stability; Lipids; CuInS2/ZnS; Bioconjugation; Zwitterionic quantum dots; CuInS/ZnS
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2014.09.020

[Display omitted] •Bioconjugatable zwitterionic QDs (ZW-QDs) were produced using lipid encapsulation.•The preparation of ZW-QDs is simple, fast, and cost effective.•The ZW-QDs are stable in solutions with high salinity and over a wide pH range.•The ZW-QDs can be applied for bioassay with low nonspecific binding.•The ZW-QDs may have broad biological and biomedical applications. 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.