References and Notes

corneas (Fig. 4, D to F). These results showed that the corneal equivalents had an active re-sponse to different grades of injury, an impor-tant functional characteristic of human corneas. These engineered corneal equivalents have immediate applications as human ocular irritancy models for evaluating new chemi-cals and drugs, as alternatives to animals (30), and in drug efficacy testing such as for wound healing. The corneal equivalents can also be used in biomedical research, for exam-ple, to study wound healing and cell-matrix interactions. This technology provides a strong basis for the development of tempo-rary or permanent cornea replacements with low rejection rates. Future research could lead to readily available, complex engineered tissues that reproduce their natural human counterparts and are suitable for implants, transplants, and biomedical research