Micromachines
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2023
·Vol. 14
·期 9
·1742
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IF 3.4
Zhiang Zhang,Bingze He,Qingqing Han,Ruokun He,Yuxuan Ding,Bing Han,Zhuo-Chen Ma
Biomimetic switchable adhesion interfaces (BSAIs) with dynamic adhesion states have demonstrated significant advantages in micro-manipulation and bio-detection. Among them, gecko-inspired adhesives have garnered considerable attention due to their exceptional adaptability to extreme environments. However, their high adhesion strength poses challenges in achieving flexible control. Herein, we propose an elegant and efficient approach by fabricating three-dimensional mushroom-shaped polydimethylsiloxane (PDMS) micropillars on a flexible PDMS substrate to mimic the bending and stretching of gecko footpads. The fabrication process that employs two-photon polymerization ensures high spatial resolution, resulting in micropillars with exquisite structures and ultra-smooth surfaces, even for tip/stem ratios exceeding 2 (a critical factor for maintaining adhesion strength). Furthermore, these adhesive structures display outstanding resilience, enduring 175% deformation and severe bending without collapse, ascribing to the excellent compatibility of the micropillar’s composition and physical properties with the substrate. Our BSAIs can achieve highly controllable adhesion force and rapid manipulation of liquid droplets through mechanical bending and stretching of the PDMS substrate. By adjusting the spacing between the micropillars, precise control of adhesion strength is achieved. These intriguing properties make them promising candidates for various applications in the fields of microfluidics, micro-assembly, flexible electronics, and beyond.Keywords:switchable adhesion;two-photon polymerization;mushroom-shaped micropillars
研究领域:
材料科学
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仿生学
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微纳米制造
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产品关联
DOI
PubMed
高影响因子
Small
·
2024
·
IF 13
Ye Tian,Li Xin Hou,Xin Ning Zhang,Miao Du,Qiang Zheng,Zi Liang Wu
Soft-lithography is widely used to fabricate microstructured surfaces on plastics and elastomers for designable physical properties such as wetting and adhesions. However, it remains a big challenge to construct high-aspect-ratio microstructures on the surface of hydrogels due to the difficulty in demolding from the gel with low strength and stiffness. Demonstrated here is the engineering of tough hydrogels by soft-lithography to form well-defined micropillars. The mechanical properties of poly(acrylamide- co -methacrylic acid) hydrogels with dense hydrogen-bond associations severely depend on temperature, with Young's modulus increasing from 8.1 MPa at 15 °C to 821.8 MPa at −30 °C, enabling easy demolding at low temperatures. Arrays of micropillars are maintained on the surface of the gel, and can be used at room temperature when the gel restores soft and stretchable. The hydrogel also exhibits good shape-memory property, favoring tailoring the morphology with a switchable tilt angle of micropillars. Consequently, the hydrogel shows tunable wetting and adhesion properties, as manifested by varying contact angles and adhesion strengths. These surface properties can also be tuned by geometry and arrangement of micropillars. This facile strategy by harnessing tunable viscoelasticity of supramolecular hydrogels should be applicable to other soft materials, and broaden their applications in biomedical and engineering fields.
研究领域:
材料科学
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生物医学工程
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表面工程
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产品关联
DOI
PubMed
高影响因子
Additive Manufacturing
·
2025
·
IF 11.1
Zhaofa Zhang,Li Wang,Tianxue Yin,Yulin Zheng,Yuechen Pei,Shijia Wei,Yu Luo,Huaying Wu,Bingheng Lu
Three-dimensional (3D) micro-structured gold electrodes offer remarkable advantages in electrochemical sensing, electrocatalysis and energy storage. However, conventional cleanroom fabrication methods, such as lithography and vapor deposition, rely on expensive equipment and often involve material waste. This work proposes an EHD jet printing process for fabricating a micro-structured electrode featuring a 3D gold micropillar array (GMA) using water-based gold nanoparticle ink. Through COMSOL simulations, the utilization and avoidance of the electrostatic autofocusing effect is proposed in terms of the single micropillar and micropillar array, thereby obtaining the optimal micropillar height and spacing for the GMA. To address the tilting and detachment issues, the GMA was printed on an electrochemically deposited gold particle-dendrite layer, significantly enhancing the adhesion between the micropillars and substrate. Along with the proposed stepwise sintering process, the fabricated 3D GMA electrode exhibited excellent structural integrity. Subsequently, the fabricated 3D GMA electrode was applied to non-enzymatic electrochemical glucose detection and the results show that, compared to a planar electrode, the hybrid working electrode of the sensor demonstrated a 534 % increase in electrochemical active surface area and a notably high ratio of 6.25 cm 2 /cm 2 was obtained. This work highlights the potential of EHD jet printing for fabricating robust 3D micro-structured gold electrodes, offering a reliable, cost-effective and promising solution for applications in biomedical detection and advanced healthcare technologies.
研究领域:
生物医学工程
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材料科学
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传感器技术
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产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2024
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IF 8
Hemin Pan,Deqing Mei,Shuo Han,Xin Li,Zhuzheng Qian,Qilin Hu,Yancheng Wang
The accurate and efficient manipulation of particles and droplets is crucial for the fields of disease diagnosis, target drug delivery, and sample purification, specific microstructure-based particle and droplet manipulation have been widely utilized in bioassays. However, current techniques are mainly based on the fixed microstructures, which is extremely difficult to achieve dynamic modulation by adjusting microstructure morphology and excitation conditions. Herein, we present a novel particle capture and droplet manipulation methodology by using morphologically reconfigurable magnetic micropillar arrays incorporate with acoustic streaming effects, which enables reconfigurable particle capturing, cargo transportation, and droplet manipulation. The mechanism is to assemble NdFeB magnetic powders by magnetic gradient fields to form morphologically variable magnetic micropillar arrays with porous surfaces, and the localized acoustic streaming effects generated by surface acoustic waves (SAWs) enable micropillar arrays to capture nearby particles onto the surfaces or to drive perturbations in droplets in the vicinity. To demonstrate the capabilities of this technology, we have achieved the high-volume acoustofluidic particle capture and loading (0.214 MCF), targeted complex maze navigation, efficient droplets manipulation (≤ 3.96 mm/s), and acoustofluidic mixing acceleration (≤ 2.5 s). Therefore, this technique enables reconfigurable and versatile manipulation of particles and droplets in biomedical applications.
研究领域:
微流控
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生物医学工程
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声学
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材料科学
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DOI
高影响因子
RSC Advances
·
2020
·Vol. 10
·期 67
·41110-41119
·
IF 3.119
Chaozhan Chen,Bin Ran,Zhenxing Wang,Hongli Zhao,Minbo Lan,Huaying Chen,Yonggang Zhu
Micropillar array electrodes (μAEs) have been widely applied in electrochemical detection owing to their advantages of increased mass transport, lower detection limit, and potential to be miniaturized. This paper reports the fabrication, simulation, surface modification, and characterization of PDMS-based μAEs coated with gold films. The μAEs consist of 9 × 10 micropillars with a height of either 100 μm, 300 μm, or 500 μm in a 0.09 cm2 region. Numerical simulation was employed to study the influence of geometrical parameters on the current density. The μAEs were fabricated by soft lithography and characterized using both SEM and cyclic voltammetry. Experiments revealed that high pillars enabled enhanced voltammetric current density regardless of the scan rates. The platinum–palladium/multi-walled carbon nanotubes (Pt–Pd/MWCNTs) were coated on the μAEs to improve their electrochemical detection capability. The μAEs demonstrated 1.5 times larger sensitivity compared with the planar electrode when hydrogen peroxide was detected. Furthermore, μAE500 with Pt–Pd/MWCNTs was employed to detect sarcosine, a potential biomarker for prostate cancer. The linear range and limit of detection for sarcosine were from 5 to 60 μM and 1.28 μM, respectively. This detection range covers the concentration of sarcosine in human tissues (0–60 μM). These results suggest that the μAEs have better detection performance in comparison to planar electrodes due to their large surface area and pillar height. This paper provides essential guidelines for the application of μAEs in high sensitivity electrochemical detection of low abundance analytes.
研究领域:
电化学
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生物传感器
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纳米技术
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癌症诊断
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）