Fig 2: A brief workflow of the conjugation of gold nanoparticles with exosomes. The orange sphere represents the citrate-capped gold nanoparticle (CGNP). Upon incubation with PEG, it forms PEGylated gold nanoparticle (PGNP). Anti-CD63 antibody is conjugated to the PGNP after activating it with EDC/SNHS chemistry.

Fig 3: Western blot performed on gold nanoparticle conjugated with anti-CD63. The blot shows the western results of SDS-PAGE loaded with GNP conjugated with different concentrations of anti-CD63. The blot is incubated with secondary antibody and developed. The experiment was performed several times.

Fig 4: (a) Mechanism of exosome lysis by Electric Field. (i) Exosome immobilized on the SPE functionalized with anti-CD63 Antibody. (ii) Low-Voltage Lysis of Exosome. Due to the applied voltage on the SPE, the charged nature of exosomes becomes partially disturbed, resulting in the release of its contents. (iii) Rupture of exosomes due to High Voltage. Exposing the solution containing exosomes to high voltages can rupture the exosomes as well as their proteins to fragments, making them unusable for further processing. (b) Generation of HER2 Quantification curve and quantification of unknown concentration of HER2. A known concentration of HER2 antigen is immobilized on the SPE, functionalized with anti-HER2 Antibody. The corresponding data obtained after the Electrochemical Impedance Spectroscopy (EIS) sensing are used to fit the Randles circuit. The capacitance (CPE) from the circuit is plotted against the concentration of HER2 (CPE = 6.54 (µg of HER2) + 6.29)). Serum from the volunteer is used for isolating exosomes and Lysing. The lysate solution is used for (EIS) sensing and compared with the standard curve. Approximately similar results are seen for SPEs conjugated with saturated (1 µL) and non-saturated (1/100 µL) concentrations of Anti-HER2 Antibody.

Fig 5: The flow of the work. a: Polyethylene Glycol (PEG) functionalized on the Screen-Printed Electrode (SPE); b: Activation of COOH group of PEG with EDC NHS; c: SPE functionalized with anti-CD63 Antibody and immobilized with exosome; d: Lysing of exosomes on SPE by electric field; e: SPE functionalized with anti-HER2 Antibody; f: Immobilization of exosomal protein (HER2) on the SPE functionalized with anti-HER2 Antibody.