{HEAD ~ A TSG6 polypeptide} can be delivered by a controlled release or {TAIL ~ sustained release system} 
delivered by
{ HEAD ~ A TSG6 polypeptide } can be delivered by a controlled release or { TAIL ~ sustained release system }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL