Pig heart valves are currently implanted into humans, but Yancy says that an entire heart could prove to be too much for the body to tolerate. 揚西說，儘管目前可以將豬的心臟瓣膜植入人體，但是整個心臟對於人體來說可能難以承受。
Another additional hurdle,developing tiny GPS receiver chips that could be embedded yet still be sensitive enough to receive signals from thousands of miles out in space. 而另一個不可忽視的因素則是全球定位系統信息接收晶元，它不但要能植入人體內，並且還應有足夠的靈敏度，以接收來自幾千英裡外的太空定位衛星群發來的信息。
