Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Imidazolium-dysprosium-based magnetic NanoGUMBOS for isolation of hemoglobin Mingyan Cong a , Rocío L. Pérez a , Mi Chen a , Ramakanta Chapai b , Rongying Jin b , Punprabhashi Vidanapathirana c , Isiah M. Warner a,∗ a Chemistry Department, Louisiana State University, Baton Rouge, LA, 70803, United States b Department of Physics & Astronomy, Louisiana State University, Baton Rouge, LA, 70803, United States c Department of Chemistry, North Carolina A&T State University, Green Sboro, NC, 27405, United States ARTICLEINFO Keywords: Hemoglobin isolation Magnetic solid phase extraction NanoGUMBOS Dysprosium ABSTRACT A novel imidazolium-dysprosium-based magnetic nanomaterial, i.e. [C 16 mim] 5 [Dy(SCN) 8 ] nanoGUMBOS (na- nomaterials fabricated from a group of uniform material based on organic salts), was prepared using a facile method for selective hemoglobin (Hb) isolation. In this nanomaterial, the imidazolium cation serves as a se- lective Hb affinity group, while dysprosium contributes paramagnetic properties. Through a combination of the advantages of ionic liquids, magnetic adsorbent, and nanoscale solid phase extraction, [C 16 mim] 5 [Dy(SCN) 8 ] nanoGUMBOS exhibit great selectivity toward Hb and a favorable extraction efficiency of 95.4% when 1 mL of 100 μg/mL Hb solution is processed with 0.6 mg of [C 16 mim] 5 [Dy(SCN) 8 ] nanoGUMBOS. As the Hb con- centration increased to 800 μg/mL, the adsorption capacity approached ∼840 μg/mg. The adsorbed protein is recovered with an elution efficiency of 87% by using 1% SDS solution. This novel nanoGUMBOS solid-phase extraction procedure was successfully applied to selective isolation of Hb from human whole blood and verified using SDS-PAGE. This simple strategy is a novel approach towards fabrication and use of a nanoadsorbent for selective isolation of proteins. 1. Introduction Proteins are an important group of biomolecules that play essential roles in structure, function, and regulation of cells, tissues, and organs of humans. However, due to the typical complexity of the biological environment, protein purification from biological matrices is often a challenging process and thus is a crucial issue in bioscience separations. In this study, we focus on isolation of hemoglobin (Hb), which is a protein with four heme groups and is abundantly present in human red blood cells. Each heme group contains a ferrous cation that is re- sponsible for oxygen transportation [1,2]. Hemoglobin's oxygen trans- portation properties make it potentially useful for production of blood substitutes for blood transfusions in extreme situations, particularly for persons with rare blood types [3–6]. Therefore, as a prerequisite step for such investigations, isolation of Hb has drawn considerable atten- tion over the last decade. Over the past ten years, several studies on ionic liquid-based liquid- liquid extractions of Hb have been conducted, where the designated ionic liquid (IL) showed good Hb extraction [7–9]. Ionic liquids (ILs) are defined as low melting organic salts that can be easily designed to possess useful properties such as biocompatibility, thermal stability, low vapor pressure, considerable ionic conductivities, broad electro- chemical window, as well as good solubility and miscibility [10]. Due to these unique properties, ILs have attracted wide recognition as novel green solvents in chemistry [11–14], particularly for extraction of analytes [15–17]. In addition, the application of ILs in liquid-liquid extraction systems addresses several issues regarding toxicity of organic solvents [15,18,19]. However, problems associated with liquid-liquid extractions, such as incomplete phase separation and disposal of large amounts of solvents, make this method less favorable in practice [7,20]. In this regard, solid-phase extraction (SPE) overcomes many of the problems noted above [21–24]. In recent years, interest in magnetic solid-phase extraction (MSPE), especially extractions based on mag- netic nanomaterials, has increased in order to reduce the time-con- suming separation process and provide increased surface area interac- tions. However, conventional extractions using magnetic nanoparticles are generally based on surface functionalization of magnetic nano- particles using affinity ligands to increase the selectivity and efficacy of the extraction procedure [25–33]. Frequently, the preparation of these types of nanomaterials with surface functionalization requires tedious https://doi.org/10.1016/j.talanta.2019.06.078 Received 11 March 2019; Received in revised form 19 June 2019; Accepted 20 June 2019 ∗ Corresponding author. E-mail address: iwarner@lsu.edu (I.M. Warner). Talanta 205 (2019) 120078 Available online 29 June 2019 0039-9140/ © 2019 Published by Elsevier B.V. T