This preferably comprises a layer 30 that is substantially the same as {HEAD ~ any} of the spreading layers of {TAIL ~ the aforesaid 158 patent}, provided that it is free of detection reagents 
This preferably comprises a layer 30 that is substantially the same as { HEAD ~ any } of the spreading layers of { TAIL ~ the aforesaid 158 patent } , provided that it is free of detection reagents
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH