Abstract
The influence of using plasticized poly(vinyl chloride) (PVC) membranes in the culturing of cells was examined in order to apply an array-type semiconductor calcium ion image sensor to the bioimaging of living cells. Two plasticized PVC membranes, CaHDOPP-DOPP and K23E1-NPOE, were prepared from optimal membrane contents. The plasticized PVC membranes were characterized by the potential response to calcium ion. The K23E1-NPOE membrane had a high sensitivity to a low concentration of calcium ion. The linear dynamic ranges of the K23E1-NPOE membrane and the CaHDOPP-DOPP membrane were 10−2 − 5 × 10−7 M and 10−2 − 1 × 10−5 M, respectively. The plasticizers leaked from the membrane to an aqueous solution were measured by gas chromatography. The leakage of DOPP was significantly detected. However, the leakage of NPOE was not detected, and the concentration was less than the detection limit. A aqueous solutions that kept long contact with the membranes were examined by the growth observation of HeLa cells. The first contact solutions were prepared by contact with the membranes for 6 hours at room temperature. The second contact solutions were prepared with the same membrane and under the same condition after the first contact solution was removed. The contact solutions never killed the cells. The contact solutions inhibited cell proliferation for 24 hours during the cultivation. In all of the contact solutions, however, all cells grew up to form a cluster after more than 48 hours, similar as in the controlled solution. The inhibition effect of contact solutions of CaHDOPP-DOPP was stronger than that of K23E1-NPOE. In addition, the inhibition effect of both second contact solutions was weaker than that of both first contact solutions. Probably, a conventional conditioning of plasticized PVC membranes is effective for reducing the inhibition effect of the cell proliferation. In conclusion, the K23E1-NPOE membrane was superior to the CaHDOPP-DOPP membrane to apply plasticized PVC membrane to Ca2+ imaging of living cells with array type semiconductor sensors.
