HeLa cells directly immobilized on gold-patterned silicon substrate were used to assess the biological toxicity of anticancer drugs (hydroxyurea and cyclophosphamide). Immobilization of HeLa cells was confirmed by optical microscopy, and cell growth, viability and drug-related toxicity were examined by cyclic voltammetry and potentiometric stripping analysis. The voltammetric behaviors of HeLa cells displayed a quasi-reversible pattern with the peak current exhibiting a linear relationship with cell number. The attached living cells were exposed to different concentrations of hydroxyurea and cyclophosphamide as anticancer drugs, which induced the change of cyclic voltammetry current peak. As the exposed concentration of anticancer drugs was increased, the change of current peak was increased, which indicates the decrease of cell viability. Trypan Blue dyeing was performed to confirm the results of the effect of anticancer drugs on the cell viability which was obtained from cyclic voltammetry assay. The proposed direct cell immobilization method technique can be applied to the fabrication of cell chip for diagnosis, drug detection, and on-site monitoring.

In vitro assays have generally been carried out for cytological diagnosis and for evaluation of the cytotoxic effect of chemotherapeutic agents as an alternative to animal experiments. In this study, a method for fabrication and application of a gold nanoflower array on an ITO substrate for evaluation of the effect of chemotherapeutic agents on cancer cell behavior by the surface-enhanced Raman scattering (SERS) analysis, as well as the electrochemical detection was described. Due to the increased sensitivity provided by gold nanoflower substrates, the effect of chemotherapeutic agents at low concentration level was successfully detected based on SERS technique. This substrate was found to give enhanced Raman spectra with high surface plasmon field in the near infrared (NIR) spectral range, which minimize fluorescence interference and photo-toxicity. Cyclic voltammetry (CV) was further performed for confirmation of results obtained by SERS assay and showed increased intensity of current peaks for various concentrations at low levels. The developed Au nanoflowers modified ITO substrates developed in this study could be used as a simultaneous SERS and CV substrate to determine the effects of chemotherapeutic agents on cancer cells.

Cell–cell and cell–extracellular matrix (ECM) adhesion are fundamental and important in the development of a cell-based chip. In this study, a novel, simple, rapid, and one-step technique was developed for the fabrication of a uniform three-dimensional mesoporous gold thin film (MPGF) onto a gold (Au) coated glass plate based on an electrochemical deposition method. Scanning electron microscopy images demonstrated that the resulting MPGF electrode had uniformly distributed pores with diameters of about 20 nm. The cyclic voltammetric behavior of [Fe(CN)6]4 − /3 − coupled onto MPGF and Au electrodes demonstrated that the MPGF electrode had a higher electrocatalytic sensitivity and reversibility than the bare Au electrode. The Arg–Gly–Asp (RGD) sequence containing the peptide was immobilized on the MPGF and bare Au substrates. HeLa cancer cells were then cultured on the RGD peptide layer. The successful immobilization of the peptide and cells was confirmed by atomic force microscopy. The cell proliferation and viability were evaluated by cyclic voltammetry and Trypan blue dyeing assay. These results indicated that the RGD/MPGF modified electrodes showed an electrochemical sensitivity in the detection of cancer cells which is approximately three times higher, especially at low cell density, than RGD/Au electrodes. This much improved sensitivity of the MPGF modified electrode demonstrates the potential for the fabrication of a highly sensitive and low-cost cell-based chip for rapid cancer detection.

A similarity solution is presented for the heat transfer flow considering slip conditions along with hall and ion-slip currents. The governing partial differential equations are reduced to a system of ordinary differential equations and then solved numerically by the method of Nachtsheim-Swigert shooting iteration technique based of Runge-Kutta sixth order iteration scheme. Results for the non dimensional velocity and temperature profiles are shown graphically for a range of values of the problem parameter. The profiles for shear stress due to primary and secondary velocity and temperature gradient are also studied.