{TAIL ~ A biosensor} 18 in which {HEAD ~ the first second receptor moieties} are Fab fragments which recognize different antigenic determinants 
{ TAIL ~ A biosensor } 18 in which { HEAD ~ the first second receptor moieties } are Fab fragments which recognize different antigenic determinants
TAIL TAIL TAIL TAIL TAIL TAIL OTH REL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH