Business

Using an adaptive strategy, Chinese hamster ovary (CHO) cell lines were developed that are capable of robust growth in serum-free suspension culture. These preadapted derivatives of the commonly used strain of CHO cells (CHO DUKX), termed PA-DUKX, were used for the introduction and stable expression of several heterologous human genes. A significant advantage of recombinant PA-DUKX cells was their ability to readily resume growth in serum-free suspension culture after transfection and amplification of heterologous genes. Expression of recombinant human proteins in PA-DUKX cells was quantitatively similar to that of lineages generated using conventional CHO DUKX cells. In addition, recombinant human proteins expressed by transfected PA-DUKX lineages were shown to be biochemically and structurally similar to those expressed in CHO DUKX cells, PA-DUKX host cell technology provides an opportunity for reducing the time and resources required to develop large-scale, suspension culture-based manufacturing processes employing serum-free medium. (c) 1996 John Wiley & Sons, Inc.

The dye-sensitized solar cell is a new and renewable energy device that aims to compete with conventional fuels with its low cost and ease to manufacture. While the efficiencies of dye-sensitized solar cells are improving, they are not yet cost-competitive with current energy sources such as coal. Our project focuses on improving the efficiency of these organic solar cells by adding a self-assembled monolayer (SAM) in between the electron donor, a dye called Z907, and the semiconductor, nanoporous titania (TiO2). This SAM will theoretically reduce an unfavorable process called recombination, in which the light-excited electrons fall from their high-energy state directly back into the dye or hole-transport medium, instead of flowing through the circuit. The SAM molecules that we are using have a phosphonic acid head which should bind readily to the TiO2, and an amine group tail to tether the dye. To deposit the SAMs, the phosphonic acids are first dissolved in an organic solvent with the help of either acid (HCl) or base (KOH). We used Fourier Transform Infrared Spectroscopy (FTIR) to see what differences there were between acidic and basic deposition. FTIR analysis showed greater attachment of SAMs using acidic solutions rather than basic solutions for two out of the three SAMs. In the third, deposition was fairly even. By developing a reliable procedure to deposit SAMs onto titania, we will be able to more accurately test the effects of SAMs on dye-sensitized solar cells. This could improve the efficiencies of these organic devices and possibly offer a greener and cost-competitive alternative to fossil fuels.