Copper-Decorated Titanate Nanosheets: Novel Homogeneous Monolayers with a Superior Capacity for Selective Isolation of Hemoglobin

Novel unilamellar and homogeneous titanate nanosheets were prepared by anchoring (3-aminopropyl)triethoxysilane (APTES) and chelating copper ions, also know by the short form Cu-APTES-TiNSs. The nanosheets were uniform two-dimensional lamellas/monolayers with a thickness of 1.9 nm, and they were further characterized by atomic force microscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma mass spectrometry, and N₂ adsorption-desorption. The copper-decorated titanate nanosheets possess a copper content of 4.28 ± 0.14% and exhibit a favorable selectivity to the adsorption of hemoglobin, with a considerable capacity of 5314.2 mg g^-1. The adsorbed hemoglobin is easily collected with a recovery rate of 91.3% by using 0.5% w/v sodium dodecyl sulfate as an eluent. Circular dichroism spectra confirmed that virtually no conformational alteration is observed for hemoglobin. Cu-APTES-TiNSs are further applied for the selective adsorption of hemoglobin from the human whole blood.