1220ex transmission electron microscope

Droplets containing 100 μl of diluted (1 mg/ml) pH7.5–8.0 His-tagged recombinant N92 amelogenin were placed on carbon coated copper TEM grids (Ted Pella, Redding, CA) and incubated in a moisturized container at 37°C for 2 h. Thereafter, TEM grids were quickly rinsed with DDW, immersed into 100 μl of freshly prepared 1% NiSO₄ (Sigma, St. Louis, MO) solution for 30 min, quickly rinsed with DDW again, air dried, and analyzed using a JEOL 1220EX transmission electron microscope at the UIC Research Resources Center (Chicago, IL).

Differentiated cell clusters were sequentially fixed in a 1 % glutaraldehyde and 1 % paraformaldehyde solution of 0.1-M phosphate buffer, pH 7.4, for 1 h. After a brief rinse in phosphate buffer, the cell clusters were post-fixed with 2 % OsO₄ in phosphate buffer for 2 h, followed by methanol dehydration and embedding between Aclar films (Nisshin EM, Tokyo, Japan) with Epon812. Ultrathin sections were subsequently cut and collected on Formvar-coated single-slot grids. The sections were stained with uranyl acetate and Reynolds’ solution and examined with a JEOL 1220EX transmission electron microscope (JEOL GmbH, Freising, Germany).

Three days postnatal mouse molar tooth organs as well as E16 tooth organs cultured for 12 days were fixed in Karnovsky's fixative as previously described (Diekwisch, 1998 (link)), dehydrated and embedded in Eponate 12 (Ted Pella, Redding, CA). Sections were cut on a Leica Ultracut UCT ultramicrotome. After drying, sections were contrasted in 1% uranyl acetate followed by Reynold's lead citrate for 15 min each. Observations were made on a JEOL 1220EX transmission electron microscope at the UIC Research Resources Center (Chicago, IL).