DNA electrochemistry
Agilent,
Motorola, others
in use,
not sensitive enough
Nanotube electrochemistry
NASA
Nanowire-based
Lieber,
Williams (HP)
25 pM
Nanoparticle aggregation
Mirkin Nothwestern
100 pM
Cantilever based detection
Guntherodt, Basel, etc
30 pM
Nanopore technology
unproven