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In the practice of in vivo imaging with carbon nanodots (CNDs) as probe, the volume of CNDs solution introduced into living body should be kept at minimum, and a higher concentration is needed to ensure sufficient quantity of the probe for obtaining bright image. Therefore, the improvement on biocompatibility of the CNDs is among the most important and critical issues. We report herein the improvement on the biocompatibility of CNDs with modification by ionic liquid. Amide group functionalization of carbon nanodots is first conducted through microwave irradiation, followed by coupling the ionic liquid 1-carboxymethyl-3-methyl imidazolium bromide on the surface of the Amide-CNDs via covalent conjunction to produce the modified carbon nanodots (IL-CNDs). This modification process significantly improved the biocompatibility of CNDs, as demonstrated by cell imaging at a higher concentration of CNDs. Both Amide-CNDs and IL-CNDs exhibit abundant surface functional groups, resulting in tunable fluorescent emission feature and potential applications in two-color cell imaging. [ABSTRACT FROM AUTHOR]

Abstract: Hemoglobin (Hb) modified magnetic nanocomposites are prepared by immobilization of Hb onto the surface of amino-functionalized Fe3O4@SiO2 magnetic nanoparticles via covalent bonding with glutaraldehyde as cross-linker. The obtained nanocomposites are characterized with FT-IR, SEM, XRD and surface charge analysis. A direct solid-phase extraction procedure for the isolation/separation of plasmid DNA using this nanocomposite as a novel adsorbent is thus developed. Some important experimental parameters governing the sorption efficiency, i.e., the pH of sample solution and the ionic strength, are investigated. The Hb modified magnetic nanocomposites provide a sorption capacity of 27.86mgg−1 for DNA. By using 2.0mg of the nanocomposites as sorption medium and a suitable acidity of pH 6.1, a sorption efficiency of 93% is achieved for 25μgmL−1 of DNA in 1.0mL of sample solution. Afterwards, the absorbed DNA could be readily recovered by using 1.0mL of Tris–HCl buffer (pH 8.9, 0.01molL−1), giving rise to a recovery of ca. 68.3%. The present solid-phased extraction protocol is applied for the isolation of plasmid DNA from Escherichia coli culture, resulting in comparable yield and purity of plasmid DNA with respect to those obtained by using commercial kits. [Copyright &y& Elsevier]

By taking advantage of the structural tunability of ionic liquids (ILs), a series of imidazolium ILs were employed as precursors to prepare carbon dots (IL-CDs) and as regulators to control their properties. The simultaneous formation of hydrophilic CDs (IL-HCDs) and organophilic CDs (IL-OCDs) is achieved in hydrothermal reaction system by undergoing sulfuric acid carbonization. The quantum yields (QY) of IL-OCDs are closely correlated with both the cationic and anionic moieties of the ionic liquids, i.e., longer side chains of cations in the imidazolium ILs and weakly nucleophilic anions tend to produce highly fluorescent IL-OCDs. Both IL-HCDs and IL-OCDs exhibit low cytotoxicity, and that of IL-HCDs is even lower than IL-OCDs. A drug delivery system is constructed by combining anticancer drug curcumin (Cur) with IL-OCDs via hydrophobic interaction, among which 1,3-dibutylimidazolium nitrate derived IL-OCDs exhibit highest photoluminescence. In addition, it serves as a favorable drug carrier with high drug loading efficiency and facilitates rapid penetration/transportation of Cur into the cell interior, which significantly accelerates the apoptosis of HeLa cells. This process is further visualized by cell imaging. [ABSTRACT FROM AUTHOR]

A ferrate functionalized graphene-based composite is prepared by growth of hydrous ferric oxide (FeOOH) on the polyethylene glycol (PEG) modified graphene oxide (GO) sheets. The obtained GO–PEG–FeOOH composite is characterized by ATR-FTIR, TEM, AFM, XPS and ICP-MS. The PEGylation significantly changes the surface property of the bare graphene oxide, which not only generates a nano-bio-interface for protein interaction but also reduces the non-specific adsorption of proteins. The PEGylation and growth of FeOOH nanorods on GO sheets obviously enhanced the selectivity toward the adsorption of albumin through strong hydrogen bonding interaction, exhibiting an ultra-high adsorption capacity of 1377.4 mg g −1 for bovine serum albumin (BSA). It is obviously higher than those achieved by any hitherto reported graphene based materials and other carbon nanomaterials. Albumin retained by the composite could be effectively recovered with a 4.0 mM B–R buffer through the affinity of boronic acid toward protein, giving rise to a recovery of 70%. Circular dichroism (CD) spectra indicate no conformational change for BSA during the process of adsorption/desorption. The practical applicability of the GO nanocomposite is further demonstrated by the selective adsorption/isolation of albumin from complex biological samples matrixes, e.g., human whole blood. [ABSTRACT FROM AUTHOR]