Fig. 2: Calibration of voltage shifts to target concentration.

a–e Schematic showing the assay steps of the NGEMS platform. The washing step with 4×PBS and 0.1×PBS buffer is employed after each sample and nanoparticle incubation step before an CVC is recorded. a Sample is incubated for 20 min on the anti-ApoAI functionalized AEM surface and then the wash steps employed. b Captured HDL on the AEM surface that gives a CVC used as the baseline signal. c Addition of silica particles functionalized with anti-PON1 (Si-NP) gives a voltage shift depending on number of captured PON1-HDL. d Addition of silica particles with anti-ApoAI (Si-NP') binds to unoccupied HDL in c giving a shift proportional to PON1-free HDL. e Direct addition of silica reporters with anti-ApoAI (Si-NP') binds to all the HDL giving a shift proportional to HDL-P (total HDL). Silica is significantly larger than HDL thus allowing only one Silica nanoparticle per HDL. a–e and its key was created with biorender.com. f Typical CVC of two-step sequential (Si-NP and Si-NP') reporter addition strategy as shown in c and d for PON1-HDL and PON1-free HDL. g Typical CVC of one-step Si-NP' reporter addition strategy as shown in e for HDL-P (total HDL). Calibration plots for PON1-HDL h, PON1-free HDL i and HDL-P j shown as average of at least five replicates of each concentration with the error bars as the standard deviation. Same sample was measured repeatedly at every given concentration on different NGEMS sensors.