Construction of the recellularized corneal stroma using porous acellular corneal scaffold

Acellular porcine cornea stroma (APCS) prepared using pancreatic phospholipase A2 was proven to be promising corneal scaffold. However, its dense ultrastructure provides insufficient space that prevents the seeded cells from organizing into a functional tissue. In this report, freezing dry APCS (FD-APCS) biomaterials containing pores with different sizes were fabricated at different pre-freezing temperatures of −10, −80 or −198 °C, and the percentage of large pores (equivalent circle diameter ≥ 10 μm) was 93.55%, 69.36%, 35.79%, while the small pores (<10 μm) were account for 6.45%, 30.64%, 64.21%, respectively. Both porosity and specific surface area increased in FD-APCS fabricated with decreased pre-freezing temperature, and they were dramatically higher than those in APCS. The three FD-APCS groups displayed higher permeability than APCS, and the −10 °C FD-APCS possessed the highest permeability. The keratocytes seeded in the FD-APCS construct survived well in vitro, and maximal cell proliferation was observed in the −10 °C FD-APCS. The light transmittance of the FD-APCS-transplanted cornea after interlamellar keratoplasty in rabbit eyes displayed no significant difference from the APCS-transplanted or native cornea. This study indicated that the porous FD-APCS prepared using pancreatic phospholipase A2 is capable of serving as potential scaffold for constructing tissue-engineered cornea with biological properties.