Fig 1.
The microchip consists of three modules: glass iDEP micropipettes for particle trapping, the embedded micro-electrodes for impedance measurement, and PMMA substrate with holders for pipettes alignment.
Fig 2.
Step by step fabrication procedure of proposed LOC device.
Fig 3.
The picture and microscopic image of the microchip.
(A) The integrated microelectronic device. (B) Bright-field microscopic image of the alinged micropipette tip in between two sensing electrodes.
Fig 4.
The schematic illustration and the equivalent circuit of the impedance measurement system.
(A) The schematic of the impedance measurement system. Exosomes were trapped at the tip of the micropipette due to the balance of dielectrophoresis (DEP), electrophoresis (EP), and electroosmosis (EO) forces. The impedance of the vesicles was characterized by an impedance analyzer at a broad frequency spectrum (1kHz to 50 MHz) utilizing the sensing electrodes. (B) Constructed model of an equivalent circuit of the system where Lld, Cstray, Cdl, Zch, Ri, Ci, Rsh, Csh, Rmed, and Cmed represent the lead inductance, stray capacitance, electrical double-layer capacitance, channel impedance, inner core resistance, inner core capacitance, shell resistance, shell capacitance, suspending medium resistance, and suspending medium capacitance respectively.
Fig 5.
The modeling and experimental results showing the impedance of soluitons with different conductivities as a function of frequency.
(A) The results obtained from an equivalent circuit model showing the impedance of solutions with different conductivities as a function of frequency. (B) The corresponding experimental results showing the impedance of solution with different conductivities as a function of frequency.
Fig 6.
The opacity magnitude comparison of different sub-micron particles.
(A) Schematic illustration of different sub-micron particles, including COOH-PS beads, liposomes, and exosomes harvested from hTERT mesenchymal stem cells. (B) The opacity magnitude comparison among COOH-PS beads, liposomes, and exosomes from 10MHz to 50 MHz. The error bars represented standard deviation. p values p<0.05(**) considered as a significant difference.
Fig 7.
The opacity magnitude comparison of exosomes harvested from different cellular origins.
(A) Schematic illustration of exosomes harvested from hTERT mesenchymal stem cells and three different carcinoma cell lines (HCT-116, LNCap, and NSCLC obtained from ATCC Inc.). (B) The opacity magnitude comparison of exosomes harvested from different cell lines, including hTERT, HCT-116, LNCap, and SNCLC. The error bars represent the standard deviation, and p<0.05(**) considered as a significant difference.