Pharmaceutical freeze dryers are used in biomedical materials. Collagen-hydroxyapatite composite is considered to be an ideal biomedical material for bone defect repair. Before sintering and molding, a powder containing a large number of micropores is usually prepared by vacuum freeze-drying, and these micropores can be used for tissue. Growth provides a suitable physicochemical microenvironment, guides the growth of bone tissue, and improves biocompatibility.

Shi Hongcan et al. woven polypropylene monofilament and polyglycolide fiber into a straight tubular mesh tube, the inner wall was coated with polyurethane film and collagen, and the outer wall was covered with collagen-hydroxyapatite porous sponge, and designed a new type of artificial tracheal prosthesis. body. The pore size of the unique three-dimensional porous structure of the collagen-hydroxyapatite sponge by vacuum freeze drying is controlled at 100-200 μm, and the gaps are common to each other, which provides enough space for cell adhesion, crawling and tissue growth.