As summarized above, the R1 group can include a biomolecule or a chemical group enabling {HEAD ~ the amplifier} to be attached to {TAIL ~ a biomolecule} 
to be attached to
As summarized above , the R1 group can include a biomolecule or a chemical group enabling { HEAD ~ the amplifier } to be attached to { TAIL ~ a biomolecule }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL