Background: This study was designed to explore the possible use of the bladder submucosa acellular matrix (BSAM) as a cell deliverer in tissue engineering.

Methods: Smooth muscle cells (SMCs) were isolat-ed from bladder tissues by collagenase digestion and cultured and passaged in DMEM supplemented with 10% fetal bovine serum. Bladder submucosa was extracted from bladder by microdissection and washed thoroughly with 0.5% SDS and dH₂O. Smooth muscle cells were seeded onto the matrix at a density of 5.0×10⁶ cells per cm². The cell-matrix complex was harvested at 1, 2, 3 and 4 weeks. The growth of SMCs was evaluated by HE staining and electronic microscopy.

Results: SMCs adhered to the BSAM. One week later they located on the limited surface areas of the matrix or penetrated into the surfaces. After cell seeding for 2 and 3 weeks, the quantity of the cells increased markedly and most of them reached the inner side of the matrix. Four weeks after seeding, however, the number of the cells in the cell-matrix complex decreased.

Conclusions: The BSAM as a well biocompatible material in vitro can be used as a cell deliverer in tissue engineering research. The BSAM seeded with cells should be placed back to the host within 3 weeks after cell seeding.