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Hypersound (ultrasound of gigahertz (GHz) frequency) has been recently introduced as a new type of membrane-disruption method for cells, vesicles and supported lipid bilayers (SLBs), with the potential to improve the efficiency of drug and gene delivery for biomedical applications. Here, we fabricated an integrated microchip, composed of a nano-electromechanical system (NEMS) resonator and a gold electrode as the extended gate of a field effect transistor (EGFET), to study the effects of hypersonic poration on an SLB in real time. The current recordings revealed that hypersound enabled ion conduction through the SLB by inducing transient nanopores in the membrane, which act as the equivalent of ion channels and show gating behavior. The mechanism of pore formation was studied by cyclic voltammetry (CV), atomic force microscopy (AFM) and laser scanning microscopy (LSM), which support the causality between hypersound-triggered deformation and the reversible membrane disruption of the SLB. This finding contributes to the development of an approach to reversibly control membrane permeability by hypersound.
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Supporting Information
Hypersonic Poration of Supported Lipid Bilayers
Yao Lu1,2, Jurriaan Huskens2,* Wei Pang1, Xuexin Duan1,*
1. State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University,
Tianjin 300072, China.
2. Molecular Nanofabrication group, MESA+ Institute for Nanotechnology, University of Twente,
7500 AE, Enschede, The Netherlands.
* E-mail:,
Electronic Supplementary Material (ESI) for Materials Chemistry Frontiers.
This journal is © the Partner Organisations 2019
1. Microfabrication process of the integrated microchip.
Figure S1 shows the microfabrication process of the integrated microchip compose of a bulk
acoustic wave (BAW) resonator and a gold electrode. During fabrication, the relative spatial
structure of the top/bottom electrode and the piezoelectric layer will generate parasitic capacitance
and/or inductance. When the resonator vibrates at longitudinal mode, the parasitic capacitance
and/or inductance would generate a new vibrating mode, which will decrease the quality factor of
the device and affect the detection the main working mode. Thus, we tried to optimize the shape
the resonator and found that the parasitic effect would be minimized with the polygonal shape.
Figure S1. Microfabrication process of the integrated microchip.
2. Fluorescence measurements of the supported lipid bilayer.
Figure S2 shows fluorescence imaging of the supported lipid bilayer (SLB) made of N-(7-
(NBD-PE), which performs uniform green fluorescence with an integrated membrane.
In Video S1-S3, the fluorescent SLB was also made of NBD-PE to facilitate the fluorescence
imaging of the changes of SLB under hypersound.
Si SiO2Mo AlN Au
Figure S2. Fluorescence imaging of the SLB made of NBD-PE on top of the resonator.
3. Simulations of the NEMS resonator.
To understand the mechanism of membrane deformation induced by the propagation of
hypersound, we used a 2D finite element model (FEM) simulation. Figure S3 shows the simulated
patterns of the deformation of the resonator. The corresponding vertical displacements of the
resonator surface under hypersound of different input powers are illustrated in Table S1.
Figure S3. FEM simulations of the surface deformation when hypersound is activated from the
resonator. The frequency of the resonator was 1.6 GHz and the input power of hypersound was
500 mW. The color bar indicates the vertical displacement of the resonator surface during the
propagation of hypersound from min (blue) to max (red).
Table S1. The vertical displacements of the resonator surface at hypersound of different input
Power (mW)
Vertical Displacement (nm)
4. CV tests of the SLB.
As Figure S4 shows, CV curves were recorded with the SLB-coated gold electrode by
switching on and off the hypersound of different powers and durations. In the case of 250 mW
for 5 min, the curve recovered to the original state by turning off hypersound (blue dash line).
However, when the input power of hypersound was increased to 500 mW and the stimulation
time was extended to 30 min, the curve did not recover any more (purple dash line) after turning
of hypersound, which indicates that the SLB has been damaged under such high stimulation.
Figure S4. Real-time CV responses of 1 mM K3Fe(CN)6 in 1 M KCl at SLB by switching on and off the
hypersound of different input powers and durations.
5. Electrical measurements of the SLB.
Figure S5. Real-time detection of ion current on the gold electrode without SLB while switching on and
off the hypersound.
-0,2 -0,1 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7
30 Original
250 mW on (5 min)
250 mW off
500 mW on (30 min)
500 mW off
Current (μA)
Potential (V)
Figure S6. Real-time detection of ion current through the SLB in KCl solutions of different
concentrations by switching on (green arrows) and off the hypersound. The concentrations of the KCl
solutions were, successively, 2, 20, 50 and 100 mM.
Figure S7. Real-time recordings of the ion current through the SLB on the integrated device by
alternatingly switching on and off the hypersound (the input powers were successively 10, 32, 50, 100,
160, 250 mW). The electrolyte solutions were respectively NaCl, MgCl2 (2 mM in pure water).
... The gelatin membrane is then transferred and dissolved in a liquid chamber, where an off-chip EGFET is used to monitor the current variation based on the direct coupling of particle charges due to adsorption of the particles on the electrode (the detection process). [20][21][22] Because of the physical separation between the sensing area and the measurement system, the sensing electrode of the off-chip EGFET can be replaced, with the FET device itself being reused, which significantly reduces the cost of the sensor. ...
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HIGHLIGHTS • A proposed microsystem system potentially provides accurate and calibration-free measurements based on a combination of front-end particulate matter (PM) separation and back-end PM detection. • Silicon dioxide particles are used to verify the performance of the system’s virtual impactor, and an accurate cutoff diameter of 2 μm in low air flow rates can be obtained. • Experimental results suggest that the proposed microsystem has potential for accurate real-time analysis of PM pollution under complex conditions.
... Cyclic voltammetry, atomic force microscopy, and laser scanning microscopy were used together to characterize the nanopores. 111 The relationship between membrane deformation and poration induced by hypersound was carefully studied. As shown in Fig. 5e, SLB was covered on the resonator, and the gold electrode connected with FET. ...
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