A carrier for expansion of pluripotent stem cells is provided, wherein the carrier comprises a substrate comprising one or more outer surfaces, wherein the one or more outer surfaces are modified with gas plasma treatment, and one or more structured indentations on one or more of the outer surfaces. The carrier has a length at least about 0.2 mm, a width at least about 0.2 mm, and a height in a range from about 0.05 mm to 1.2 mm and each of the structured indentations has a major axis in a range from about 0.1 mm to 0.5 mm, a minor axis in a range from about 0.1 mm to 0.5 mm and a depth in a range from about 0.025 mm to about 0.5 mm. A method of making the carrier, and culturing stromal cells using the same carrier are also provided.