An electrochemical biosensor was developed for the label-free and selective detection of leukemia cells based on aptamer-modified gold electrode using electrochemical impedance spectroscopy (EIS) technique. The thiolterminated aptamer (sgc8c) selected for CCRF-CEM acute leukemia cells was self-assembled onto the gold electrode surface as recognition probe, which was characterized by cyclic voltammetry (CV) and EIS using Fe(CN) 6 3À/4À as a redox probe. The surface density of aptamers was determined by chronocoulometric method using a redox cation of Ru(NH 3 ) 6 3þ . Upon incubation of the aptamer-modified electrode with CCRF-CEM cells, the electron-transfer resistance (R et ) of Fe(CN) 6 3À/4À on the sensor surface increased substantially. Only a small R et change of the sensor to the control negative cell line RAJI was observed, indicating the excellent selectivity of the sensor. The selective capture of CCRF-CEM cells on the sensor surface was also confirmed by fluorescence microscopy. A linear relationship between R et and the logarithmic value of CCRF-CEM cells concentration was found in the range of 1 Â 10 4 to 1 Â 10 7 cells/mL, with a detection limit of 6 Â 10 3 cells/mL. This work provided a simple, convenient, lowcost and label-free method for early leukemia diagnosis.

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TiO 2 nanotube (NT) arrays have been prepared by anodic oxidation of a Ti sheet, and carbon-deposited TiO 2 NT arrays have been prepared by annealing TiO 2 NT arrays in carbon atmosphere. The biocompatibility of the as-prepared NT arrays was investigated by observing the growth of osteosarcoma (MG-63) cells on the NT arrays. The application of the TiO 2 NT arrays as a drug delivery vehicle was investigated.Both the TiO 2 NTs and the carbon-modified TiO 2 NTs have good biocompatibility supporting the normal growth and adhesion of MG-63 cells with no need of extracellular matrix protein coating. The one end-opened TiO 2 NTs can be easily filled with drugs, working as an efficient drug delivery vehicle.

In this paper, we report a very simple but efficient cationic micellar CE method for protein analysis in complex samples without any modification for the capillary wall. It was found that increased concentration (>or=2 mM) of CTAB additive in electrophoretic buffer can effectively suppress the wall adsorption of both acidic and basic proteins. The separation was improved with buffer pH decreasing from 6.0 to 3.0. By using a buffer containing 2 mM CTAB at pH 3.0, nine proteins with a wide range of pI values (4.7-11.0) were separated within 9 min with high efficiencies (>6 x 10(5) plates per meter) and good reproducibility (RSDs of migration time <0.8% for run-to-run assays) and recoveries (91.6-119.0%). This method was successfully applied to the analysis of complex biological samples, including plasma and red blood cells. Most importantly, we demonstrate the proteomic applications of the proposed method, including the analysis of tryptic digests of BSA and crude protein extracts from Escherichia coli cells. With simplicity, high efficiency, and good reproducibility, this method is promising for protein analysis in complex samples and may find its place in the future proteomic research.