Albumin from bovine serum

On day 16.5 of pregnancy, rats were sacrificed and humeruses, radiuses, ulnas, femurs, tibias, and fibulas were resected from fetal rats. These bones were cultured for 24 hours in BGJb medium (No.12591-038, Gibco) with 6 mg/ml of albumin from bovine serum (No. 010–23382, Wako), 150 μg/ml of ascorbic acid (No. 012–04802, Wako), and 10 μl/ml of penicillin-streptomycin solution (No. 168–23191, Wako). The tibias were incubated at 37°C in a humidified atmosphere of 5% CO₂.

1,3-Diaminopropanetetraacetic acid ferric ammonium salt monohydrate (PDTA·Fe(iii)) was kindly donated by CHELEST Corporation and used as received. 10-Carboxy-1-decanethiol (10-CDT) and sulfobetaine3-undecanethiol (SB) were purchased from Dojindo Molecular Technologies, Inc. NaCl, KCl, HCl, albumin, from bovine serum, fraction V (BSA), and sodium dodecyl sulphate (SDS) were obtained from FUJIFILM Wako Pure Chemical Corporation. Tris-(2-carboxyethyl)phosphine (TCEP) was supplied by Sigma-Aldrich. Micro bicinchoninic acid (BCA) protein assay kit and Dulbecco's phosphate buffered saline (DPBS) were purchased from Life Technologies Co. Tris–EDTA (TE) buffer and NaCl–tris–EDTA (NTE) buffer were purchased from Promega and Nippon Gene Co., Ltd, respectively. Silver wire was purchased from Nilaco Corporation. Sputtered silver thin films on glass substrates and silver electrode arrays were fabricated using a NIMS (National Institute for Materials Science) fabrication platform. DNA oligonucleotide probes and DNA targets were provided by Tsukuba Oligo Service Co. Ltd.