2.3 ES-SMPS size characterization
The ES-SMPS system consisted of an aerosol generator (electrospray
aerosol generator, ES; TSI 3480), a scanning mobility particle sizer
(SMPS; TSI 3080) with a nano- differential mobility analyzer (DMA)
column (TSI 3085), a condensed particle counter (CPC, TSI 3776). To
generate droplets by the electrospray aerosol generator, the electrolyte
with suitable conductivity is required and AmAc with a concentration of
20 mM has been recorded to produce droplets with the smallest size and
the best performance. Therefore, AuNPs and proteins were suspended in 20
mM AmAc in this work. For NPs differentiation, the sheath flowrate was
set as 20 L/min and aerosol flowrate was 1.5 L/min.