Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics device...Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.展开更多
Liquid-assisted laser ablation has the advantage of relieving thermal effects of common laser ablation processes, whereas the light scattering and shielding effects by laser-induced cavitation bubbles, suspended debri...Liquid-assisted laser ablation has the advantage of relieving thermal effects of common laser ablation processes, whereas the light scattering and shielding effects by laser-induced cavitation bubbles, suspended debris, and turbulent liquid flow generally deteriorate laser beam transmission stability, leading to low energy efficiency and poor surface quality. Here, we report that a continuous and directional high-speed microjet will form in the laser ablation zone if laser-induced primary cavitation bubbles asymmetrically collapse sequentially near the air-liquid interface under a critical thin liquid layer. The laser-induced microjet can instantaneously and directionally remove secondary bubbles and ablation debris around the laser ablation region, and thus a very stable material removal process can be obtained. The shadowgraphs of high-speed camera reveal that the average speed of laser-induced continuous microjet can be as high as 1.1 m sin its initial 500 μm displacement. The coupling effect of laser ablation, mechanical impact along with the collapse of cavitation bubbles and flushing of high-speed microjet helps achieve a high material removal rate and significantly improved surface quality. We name this uncovered liquid-assisted laser ablation process as laser-induced microjet-assisted ablation(LIMJAA) based on its unique characteristics. High-quality microgrooves with a large depth-to-width ratio of 5.2 are obtained by LIMJAA with a single-pass laser scanning process in our experiments. LIMJAA is capable of machining various types of difficult-to-process materials with high-quality arrays of micro-channels, square and circle microscale through-holes. The results and disclosed mechanisms in our work provide a deep understanding of the role of laser-induced microjet in improving the processing quality of liquid-assisted laser micromachining.展开更多
Although femtosecond laser microfabrication is one of the most promising three-dimensional（3D） fabrication techniques, it could suffer from low fabrication efficiency for structures with high 3D complexities. By usi...Although femtosecond laser microfabrication is one of the most promising three-dimensional（3D） fabrication techniques, it could suffer from low fabrication efficiency for structures with high 3D complexities. By using etching as a main assistant technique, the processing can be speeded up and an improved structure surface quality can be provided. However,the assistance of a single technique cannot satisfy the increasing demands of fabrication and integration of highly functional 3D microstructures. Therefore, a multi-technique-based 3D microfabrication method is required. In this paper, we briefly review the recent development on etching-assisted femtosecond laser microfabrication（EAFLM）. Various processing approaches have been proposed to further strengthen the flexibilities of the EAFLM. With the use of the multi-technique-based microfabrication method, 3D microstructure arrays can be rapidly defined on planar or curved surfaces with high structure qualities.展开更多
We describe a novel technique, low surface energy Gas Expansion Molding （GEM）, to fabricate microbubble arrays in polydimethylsiloxane （PDMS） which are incorporated into parallel plate flow chambers and tested in ...We describe a novel technique, low surface energy Gas Expansion Molding （GEM）, to fabricate microbubble arrays in polydimethylsiloxane （PDMS） which are incorporated into parallel plate flow chambers and tested in cell sorting and microcell cuTture applications. This architecture confers several operational advantages that distinguish this technology approach from currently used methods. Herein we describe the GEM process and the parameters that are used to control microbubble formation and a Vacuum-Assisted Coating （VAC） process developed to selectively and spatially alter the PDMS surface chemistry in the wells and on the microchannel surface. We describe results from microflow image visualization studies conducted to investigate fluid streams above and within microbubble wells and conclude with a discussion of cell culture studies in PDMS.展开更多
Occasionally, in complex inherent characteristics of certain rocks, especially anisotropic rocks it may be difficult to measure the uniaxial compressive strength UCS. However, the use of empirical relationships to eva...Occasionally, in complex inherent characteristics of certain rocks, especially anisotropic rocks it may be difficult to measure the uniaxial compressive strength UCS. However, the use of empirical relationships to evaluate the UCS of rock can be more practical and economical. Consequently, this study carried out to predict UCS from microfabrics properties of banded amphibolite rocks using multiple regression analysis. Based on statistical results, rock microfabric parameters, which adequately represent the UCS of a given rock type have been selected. The results show that grain size, shape factor and quartz content have high significant correlation with UCS at 95% confidence level. From multiple regression model, approximately 84% of the variance of the UCS can be estimated by the linear combination of these three parameters. However, according to model performance criteria: correlation coefficient (R = 0.919), variance account for (VAF = 97%) and root mean square error (RMSE = 4.16) the study clearly indicates that the developed model is reliable to predict the UCS. Finally, this approach can be easily extended to the modeling of rock strength in the absence of adequate geological information or abundant data.展开更多
This work aims at optimizing densification parameters as well as resistance to hydration and slag attack of MgO-Dolomite refractory grains, processed from Egyptian dolomitc-magnesite raw material up to firing for 1-4 ...This work aims at optimizing densification parameters as well as resistance to hydration and slag attack of MgO-Dolomite refractory grains, processed from Egyptian dolomitc-magnesite raw material up to firing for 1-4 h at 1400-1600 ℃, in relation to their phase composition and microfabric. Minor amount of natural ilmenite mineral (0-2 wt%), separated from Egyptian black sands was used in doping the dolomitc-magnesite.展开更多
Transient electronics,which can be controllably broken down with zero environmental impact,hold significant potential in implantable devices,hardware security,and disposable sensors.While miniaturization is essential ...Transient electronics,which can be controllably broken down with zero environmental impact,hold significant potential in implantable devices,hardware security,and disposable sensors.While miniaturization is essential for enhancing device performance,increasing integration density,and enabling new applications,degradable materials often face challenges with conventional microfabrication processes like lithography due to their sensitivity to heat and solvents.In this paper,we present a UV photodetector(PD)with micro-scale patterning,fabricated using a novel solvent-free material patterning method.The PD,consisting of molybdenum(Mo)as the electrode,zinc oxide(ZnO)as the photoactive material,and polyvinyl alcohol(PVA)as the substrate,can be dissolved in deionized(DI)water,leaving behind non-toxic byproducts.The device exhibits high responsivity over 50 A/W and an obvious response to varying sunlight intensities,demonstrating its potential for temporary,eco-friendly UV sensing applications.Additionally,we demonstrated that the photoresist used in the solvent-free material patterning method can be reused for subsequent fabrication while maintaining good registration,enhancing efficiency and reducing material waste.This approach provides a scalable and high-efficiency microfabrication strategy for integrating functional materials into unconventional platforms,offering broader applicability in next-generation transient,biodegradable,and flexible sensor technologies.展开更多
To date,various micro/nanofabrication techniques have been developed during the global nanotechnology race,such as electron-beam lithography[1],photolithography[2],nanoimprint lithography[3],and 3D nanoprinting[4,5].B...To date,various micro/nanofabrication techniques have been developed during the global nanotechnology race,such as electron-beam lithography[1],photolithography[2],nanoimprint lithography[3],and 3D nanoprinting[4,5].Benefiting from these functional techniques,micro/nanoscale patterns can be easily generated onto a broad range of materials,including metals,semiconductors,ceramics,and polymers.However,a bold and even visionary question can be raised,is it possible to make patterns on living organisms rather than inanimate objects?Despite the emergence of numerous electronic devices for biological applications,directly processing biological samples remains a challenge due to the poor biocompatibility of many micro/nanofabrication methods[6].Researchers have attempted to prepare and transfer micro/nanopatterns onto cell surfaces[7],the structural integrity of these modifications can be compromised by the growth and development of cells during culture.Moreover,intact animal skin presents greater challenges for integration with metal patterns compared to cell surfaces.展开更多
Grooved tuning forks with hierarchical structures have become some of the most widely used piezoelectric quartz microelectromechanical system devices;however,fabricating these devices requires multi-step processes due...Grooved tuning forks with hierarchical structures have become some of the most widely used piezoelectric quartz microelectromechanical system devices;however,fabricating these devices requires multi-step processes due to the complexity of etching of quartz,particularly in specific orientations of the crystal lattice.This paper proposes a one-step fabrication strategy that can form a complete hierarchical structure with only a single etching process using novel lithography patterns.The core principle of this strategy is based on the effect of the size of the groove patterns on quartz etching,whereby trenches of varying depths can be created in a fixed etching time by adjusting the width of the hard mask.Specifically,the device outline and grooved structure can be completed using a seamlessly designed etching pattern and optimized time.Furthermore,the etching structure itself influences the etching results.It was found that dividing a wide trench by including a wall to separate it into two narrow trenches significantly reduces the etching rate,allowing for predictable tuning of the etching rate for wider grooves.This effectively increases the usability and flexibility of the one-step strategy.This was applied to the manufacture of an ultra-small quartz grooved tuning fork resonator with a frequency of 32.768 kHz in a single step,increasing production efficiency by almost 45%and reducing costs by almost 30%compared to current methods.This has great potential for improving the productivity of grooved tuning fork devices.It can also be extended to the fabrication of other quartz crystal devices requiring hierarchical structures.展开更多
The high-precision integration of three-dimensional(3D)microoptical components into microfluidics in a customizable manner is crucial for optical sensing,fluorescence analysis,and cell detection in optofluidic applica...The high-precision integration of three-dimensional(3D)microoptical components into microfluidics in a customizable manner is crucial for optical sensing,fluorescence analysis,and cell detection in optofluidic applications;however,it remains challenging for current microfabrication technologies.This paper reports the in-channel integration of flexible two-dimensional(2D)and 3D polymer microoptical devices into glass microfluidics by developing a novel technique:flat scaffold-supported hybrid femtosecond laser microfabrication(FSS-HFLM).The scaffold with an optimal thickness of 1–5 μm is fabricated on the lower internal surface of a microfluidic channel to improve the integration of high-precision microoptical devices on the scaffold by eliminating any undulated internal channel surface caused by wet etching.As a proof of demonstration,two types of typical microoptical devices,namely,2D Fresnel zone plates(FZPs)and 3D refractive microlens arrays(MLAs),are integrated.These devices exhibit multicolor focal spots,elongated(>three times)focal length and imaging of the characters‘RIKEN’in a liquid channel.The resulting optofluidic chips are further used for coupling-free white-light cell counting with a success rate as high as 93%.An optofluidic system with two MLAs and a W-filter is also designed and fabricated for more advanced cell filtering/counting applications.展开更多
This paper presents a simple technique to fabricate new electrofluidic devices for the three-dimensional(3D)manipulation of microorganisms by hybrid subtractive and additive femtosecond(fs)laser microfabrication(fs la...This paper presents a simple technique to fabricate new electrofluidic devices for the three-dimensional(3D)manipulation of microorganisms by hybrid subtractive and additive femtosecond(fs)laser microfabrication(fs laser-assisted wet etching of glass followed by water-assisted fs laser modification combined with electroless metal plating).The technique enables the formation of patterned metal electrodes in arbitrary regions in closed glass microfluidic channels,which can spatially and temporally control the direction of electric fields in 3D microfluidic environments.The fabricated electrofluidic devices were applied to nanoaquariums to demonstrate the 3D electro-orientation of Euglena gracilis(an elongated unicellular microorganism)in microfluidics with high controllability and reliability.In particular,swimming Euglena cells can be oriented along the z-direction(perpendicular to the device surface)using electrodes with square outlines formed at the top and bottom of the channel,which is quite useful for observing the motions of cells parallel to their swimming directions.Specifically,z-directional electric field control ensured efficient observation of manipulated cells on the front side(45 cells were captured in a minute in an imaging area of~160×120μm),resulting in a reduction of the average time required to capture the images of five Euglena cells swimming continuously along the z-direction by a factor of~43 compared with the case of no electric field.In addition,the combination of the electrofluidic devices and dynamic imaging enabled observation of the flagella of Euglena cells,revealing that the swimming direction of each Euglena cell under the electric field application was determined by the initial body angle.展开更多
This study presents the design,fabrication,and testing of biodegradable magnesium/iron batteries featuring polycaprolactone(PCL)as a packaging and functional material.The use of PCL encapsulation minimized the electro...This study presents the design,fabrication,and testing of biodegradable magnesium/iron batteries featuring polycaprolactone(PCL)as a packaging and functional material.The use of PCL encapsulation minimized the electrochemical cell volume and supported longer discharge lifetimes and higher discharge rates than state-of-the-art biodegradable batteries.Specifically,the electrodes were separated and insulated by a 5μm-thick PCL layer that served as both a battery packaging material and a permeable coating for physiological solution to penetrate and activate the battery.A systematic investigation of the electrode size,discharge rates,electrolyte selection,and polymeric coating revealed the critical reactions and phenomena governing the performance of the Mg-based biodegradable batteries.Comparison with previous reports on biodegradable batteries and medicalgrade non-degradable lithium-ion batteries demonstrated the superior performance of PCL-coated Mg/Fe batteries at these size scales,which exhibited an energy density of 694 Wh kg^(−1) and a total volume of 0.02 cm^(3).展开更多
Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency...Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency and geometrical precision are required.Wet etching has been proven to be the most efficient etching method for large-scale production of quartz devices,and many wet etching approaches have been developed over the years.However,until now,there has been no systematic review of quartz crystal etching in liquid phase environments.Therefore,this article provides a comprehensive review of the development of wet etching processes and the achievements of the latest research in thisfield,covering conventional wet etching,additive etching,laser-induced backside wet etching,electrochemical etching,and electrochemical discharge machining.For each technique,a brief overview of its characteristics is provided,associated problems are described,and possible solutions are discussed.This review should provide an essential reference and guidance for the future development of processing strategies for the manufacture of quartz crystal devices.展开更多
Existing microfabricated atomic vapor cells have only one optical channel,which is insufficient for supporting the multiple orthogonal beams required by atomic devices.In this study,we present a novel wafer-level manu...Existing microfabricated atomic vapor cells have only one optical channel,which is insufficient for supporting the multiple orthogonal beams required by atomic devices.In this study,we present a novel wafer-level manufacturing process for fabricating multi-optical-channel atomic vapor cells and an innovative method for batch processing the inner sidewalls of millimeter glass holes to meet optical channel requirements.Surface characterization and transmittance tests demonstrate that the processed inner sidewalls satisfy the criteria for an optical channel.In addition,the construction of an integrated processing platform enables multilayer non-isothermal anode bonding,the filling of inert gases,and the recovery and recycling of noble gases.Measurements of the absorption spectra and free-induction decay signals of xenon-129(^(129)Xe)and xenon-131(^(131)Xe)under different pump-probe schemes demonstrate the suitability of our vapor cell for use in atomic devices including atomic gyroscopes,dual-beam atomic magnetometers,and other optical/atomic devices.The proposed micromolding technology has broad application prospects in the field of optical-device processing.展开更多
Semiconductor-molecule surface-enhanced Raman scattering(SERS),especially the stronger interfacial charge transfer process(ICTP),represents a frontier in the field of SERS with spectral reproducibility and unparallele...Semiconductor-molecule surface-enhanced Raman scattering(SERS),especially the stronger interfacial charge transfer process(ICTP),represents a frontier in the field of SERS with spectral reproducibility and unparalleled selectivity.Herein,through a laser microfabrication method in situ,the free-standing,super hydrophilic and vacancy-rich TiO_(2-x)/Ti is successfully synthesized.Using blue TiO_(x)/Ti(B-TiO_(x)/Ti)as preconcentrated substrate,a nanomolar-level limit of detection of 12 nmol/L at 1385 cm–1,is confirmed using crystal violet(CV)bacteriostat as a model under 532 nm excitation.Furthermore,the results demonstrate that the SERS enhancement mechanism is via the moderate adulteration of oxygen vacancy,which leads to a narrow value of band gap and increases the ICTP of substrate to molecules.Using a hand-held extractor assembled with B-TiO_(x)/Ti microfiber,the operando analysis of mixtures distributed information excited in different parts of Asian carp is facilely achieved.This work guides the controlled synthesis of vacancy-rich TiO_(2-x)/Ti nanostructure and its application in ultrasensitive extraction-SERS detection.It also provides the direction for the rapid and operando transmission of biological information with temporal and spatial concentration distribution in human tissues by highly sensitized materials.展开更多
Electrochemical biosensors have emerged as a promising technology for cancer detection due to their high sensitivity,rapid response,low cost,and capability for non-invasive detection.Recent advances in nanomaterials l...Electrochemical biosensors have emerged as a promising technology for cancer detection due to their high sensitivity,rapid response,low cost,and capability for non-invasive detection.Recent advances in nanomaterials like nanoparticles,graphene,and nanowires have enhanced sensor performance to allow for cancer biomarker detection,like circulating tumor cells,nucleic acids,proteins and metabolites,at ultra-low concentrations.However,several challenges need to be addressed before electrochemical biosensors can be clinically implemented.These include improving sensor selectivity in complex biological media,device miniaturization for implantable applications,integration with data analytics,handling biomarker variability,and navigating regulatory approval.This editorial critically examines the prospects of electrochemical biosensors for efficient,low-cost and minimally invasive cancer screening.We discuss recent developments in nanotechnology,microfabrication,electronics integration,multiplexing,and machine learning that can help realize the potential of these sensors.However,significant interdisciplinary efforts among researchers,clinicians,regulators and the healthcare industry are still needed to tackle limitations in selectivity,size constraints,data interpretation,biomarker validation,toxicity and commercial translation.With committed resources and pragmatic strategies,electrochemical biosensors could enable routine early cancer detection and dramatically reduce the global cancer burden.展开更多
A new method is presented,which can obtain high aspect ratio in SU8 structures.Instead that the top of the photo resist layers are exposed to UV light through masks in conventional lithography,the new method utilizes ...A new method is presented,which can obtain high aspect ratio in SU8 structures.Instead that the top of the photo resist layers are exposed to UV light through masks in conventional lithography,the new method utilizes a mask-back exposure technique,i.e.the SU8 resist layer coated on a mask surface (metal patterns on a glass plate),is irradiated by UV light through the back of the mask.So a desired exposure dose on the bottom of the resist layer can be easily achieved without over-exposing from its top.This has a two-fold effect,i.e.proper dose on the bottom of the resist and less internal stress.Initial experimental results show that compared to an aspect ratio of 18 obtained by conventional method,a higher aspect ratio of 32 in the SU8 structures can be achieved by this new method.展开更多
Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique t...Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique that is based on powder-bed fusion(PBF)to process metals;however,it is currently focused only on the fabrication of macroscale and mesoscale components.This paper reviews the state of the art of the SLM of metallic materials at the microscale level.In comparison with the direct writing techniques that are commonly used for micro AM,micro SLM is attractive due to a number of factors,including a faster cycle time,process simplicity,and material versatility.A comprehensive evaluation of various research works and commercial systems for the fabrication of microscale parts using SLM and selective laser sintering(SLS)is conducted.In addition to identifying existing issues with SLM at the microscale,which include powder recoating,laser optics,and powder particle size,this paper details potential future directions.A detailed review of existing recoating methods in powder-bed techniques is conducted,along with a description of emerging efforts to implement dry powder dispensing methods in the AM domain.A number of secondary finishing techniques for AM components are reviewed,with a focus on implementation for microscale features and integration with micro SLM systems.展开更多
Nanotechnology allows the realization of new materials and devices with basic structural unit in the range of1–100 nm and characterized by gaining control at the atomic, molecular, and supramolecular level. Reducing ...Nanotechnology allows the realization of new materials and devices with basic structural unit in the range of1–100 nm and characterized by gaining control at the atomic, molecular, and supramolecular level. Reducing the dimensions of a material into the nanoscale range usually results in the change of its physiochemical properties such as reactivity,crystallinity, and solubility. This review treats the convergence of last research news at the interface of nanostructured biomaterials and tissue engineering for emerging biomedical technologies such as scaffolding and tissue regeneration. The present review is organized into three main sections. The introduction concerns an overview of the increasing utility of nanostructured materials in the field of tissue engineering. It elucidates how nanotechnology, by working in the submicron length scale, assures the realization of a biocompatible interface that is able to reproduce the physiological cell–matrix interaction. The second, more technical section, concerns the design and fabrication of biocompatible surface characterized by micro- and submicroscale features, using microfabrication, nanolithography, and miscellaneous nanolithographic techniques.In the last part, we review the ongoing tissue engineering application of nanostructured materials and scaffolds in different fields such as neurology, cardiology, orthopedics, and skin tissue regeneration.展开更多
The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurati...The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurations are considered as a promising candidate to meet the requirements.In this review,recent progress of the different stamping materials and various stamping technologies are first discussed.The merits of each material,manufacturing process of each stamping method and the properties of stamping MSCs are scrutinized,respectively.Further insights on technical difficulties and scientific challenges are finally demonstrated,including the limited thickness of printed electrodes,poor overlay accuracy and printing resolution.展开更多
基金This work was supported by Taishan Scholars Project Special Funds(tsqn201812083)Natural Science Foundation of Shandong Province(ZR2019YQ20,2019JMRH0410,ZR2019BB001)the National Natural Science Foundation of China(51972147,51902132,52022037).
文摘Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.
基金financially supported by the Guangdong Provincial University Science and Technology Program(Grant No.2020KTSCX119)the Shenzhen Science and Technology Programs(Grant Nos.20200925155508001,GJHZ20190820151801786,JCYJ20210324115608024 and KQTD20170810110250357)。
文摘Liquid-assisted laser ablation has the advantage of relieving thermal effects of common laser ablation processes, whereas the light scattering and shielding effects by laser-induced cavitation bubbles, suspended debris, and turbulent liquid flow generally deteriorate laser beam transmission stability, leading to low energy efficiency and poor surface quality. Here, we report that a continuous and directional high-speed microjet will form in the laser ablation zone if laser-induced primary cavitation bubbles asymmetrically collapse sequentially near the air-liquid interface under a critical thin liquid layer. The laser-induced microjet can instantaneously and directionally remove secondary bubbles and ablation debris around the laser ablation region, and thus a very stable material removal process can be obtained. The shadowgraphs of high-speed camera reveal that the average speed of laser-induced continuous microjet can be as high as 1.1 m sin its initial 500 μm displacement. The coupling effect of laser ablation, mechanical impact along with the collapse of cavitation bubbles and flushing of high-speed microjet helps achieve a high material removal rate and significantly improved surface quality. We name this uncovered liquid-assisted laser ablation process as laser-induced microjet-assisted ablation(LIMJAA) based on its unique characteristics. High-quality microgrooves with a large depth-to-width ratio of 5.2 are obtained by LIMJAA with a single-pass laser scanning process in our experiments. LIMJAA is capable of machining various types of difficult-to-process materials with high-quality arrays of micro-channels, square and circle microscale through-holes. The results and disclosed mechanisms in our work provide a deep understanding of the role of laser-induced microjet in improving the processing quality of liquid-assisted laser micromachining.
基金Project supported by the National Natural Science Foundation of China(Grant No.51501070)
文摘Although femtosecond laser microfabrication is one of the most promising three-dimensional（3D） fabrication techniques, it could suffer from low fabrication efficiency for structures with high 3D complexities. By using etching as a main assistant technique, the processing can be speeded up and an improved structure surface quality can be provided. However,the assistance of a single technique cannot satisfy the increasing demands of fabrication and integration of highly functional 3D microstructures. Therefore, a multi-technique-based 3D microfabrication method is required. In this paper, we briefly review the recent development on etching-assisted femtosecond laser microfabrication（EAFLM）. Various processing approaches have been proposed to further strengthen the flexibilities of the EAFLM. With the use of the multi-technique-based microfabrication method, 3D microstructure arrays can be rapidly defined on planar or curved surfaces with high structure qualities.
基金supported by grants fromthe NIH/NIAID 5K25AI060884 to Lisa A.
文摘We describe a novel technique, low surface energy Gas Expansion Molding （GEM）, to fabricate microbubble arrays in polydimethylsiloxane （PDMS） which are incorporated into parallel plate flow chambers and tested in cell sorting and microcell cuTture applications. This architecture confers several operational advantages that distinguish this technology approach from currently used methods. Herein we describe the GEM process and the parameters that are used to control microbubble formation and a Vacuum-Assisted Coating （VAC） process developed to selectively and spatially alter the PDMS surface chemistry in the wells and on the microchannel surface. We describe results from microflow image visualization studies conducted to investigate fluid streams above and within microbubble wells and conclude with a discussion of cell culture studies in PDMS.
文摘Occasionally, in complex inherent characteristics of certain rocks, especially anisotropic rocks it may be difficult to measure the uniaxial compressive strength UCS. However, the use of empirical relationships to evaluate the UCS of rock can be more practical and economical. Consequently, this study carried out to predict UCS from microfabrics properties of banded amphibolite rocks using multiple regression analysis. Based on statistical results, rock microfabric parameters, which adequately represent the UCS of a given rock type have been selected. The results show that grain size, shape factor and quartz content have high significant correlation with UCS at 95% confidence level. From multiple regression model, approximately 84% of the variance of the UCS can be estimated by the linear combination of these three parameters. However, according to model performance criteria: correlation coefficient (R = 0.919), variance account for (VAF = 97%) and root mean square error (RMSE = 4.16) the study clearly indicates that the developed model is reliable to predict the UCS. Finally, this approach can be easily extended to the modeling of rock strength in the absence of adequate geological information or abundant data.
文摘This work aims at optimizing densification parameters as well as resistance to hydration and slag attack of MgO-Dolomite refractory grains, processed from Egyptian dolomitc-magnesite raw material up to firing for 1-4 h at 1400-1600 ℃, in relation to their phase composition and microfabric. Minor amount of natural ilmenite mineral (0-2 wt%), separated from Egyptian black sands was used in doping the dolomitc-magnesite.
基金supported by the National Natural Science Foundation of China(No.52375580)the Guangdong Basic and Applied Basic Research Foundation(No.2024A1515011397)+2 种基金the Department of Education of Guangdong Province(No.2023ZDZX1036)the Guangzhou-HKUST(GZ)Joint Funding Program(No.2023A03J0688)the Guangzhou Basic and Applied Basic Research Scheme(No.2024A04J6466).
文摘Transient electronics,which can be controllably broken down with zero environmental impact,hold significant potential in implantable devices,hardware security,and disposable sensors.While miniaturization is essential for enhancing device performance,increasing integration density,and enabling new applications,degradable materials often face challenges with conventional microfabrication processes like lithography due to their sensitivity to heat and solvents.In this paper,we present a UV photodetector(PD)with micro-scale patterning,fabricated using a novel solvent-free material patterning method.The PD,consisting of molybdenum(Mo)as the electrode,zinc oxide(ZnO)as the photoactive material,and polyvinyl alcohol(PVA)as the substrate,can be dissolved in deionized(DI)water,leaving behind non-toxic byproducts.The device exhibits high responsivity over 50 A/W and an obvious response to varying sunlight intensities,demonstrating its potential for temporary,eco-friendly UV sensing applications.Additionally,we demonstrated that the photoresist used in the solvent-free material patterning method can be reused for subsequent fabrication while maintaining good registration,enhancing efficiency and reducing material waste.This approach provides a scalable and high-efficiency microfabrication strategy for integrating functional materials into unconventional platforms,offering broader applicability in next-generation transient,biodegradable,and flexible sensor technologies.
基金supported by the National Natural Science Foundation of China(52203305,U21A20494,and 61927820)。
文摘To date,various micro/nanofabrication techniques have been developed during the global nanotechnology race,such as electron-beam lithography[1],photolithography[2],nanoimprint lithography[3],and 3D nanoprinting[4,5].Benefiting from these functional techniques,micro/nanoscale patterns can be easily generated onto a broad range of materials,including metals,semiconductors,ceramics,and polymers.However,a bold and even visionary question can be raised,is it possible to make patterns on living organisms rather than inanimate objects?Despite the emergence of numerous electronic devices for biological applications,directly processing biological samples remains a challenge due to the poor biocompatibility of many micro/nanofabrication methods[6].Researchers have attempted to prepare and transfer micro/nanopatterns onto cell surfaces[7],the structural integrity of these modifications can be compromised by the growth and development of cells during culture.Moreover,intact animal skin presents greater challenges for integration with metal patterns compared to cell surfaces.
文摘Grooved tuning forks with hierarchical structures have become some of the most widely used piezoelectric quartz microelectromechanical system devices;however,fabricating these devices requires multi-step processes due to the complexity of etching of quartz,particularly in specific orientations of the crystal lattice.This paper proposes a one-step fabrication strategy that can form a complete hierarchical structure with only a single etching process using novel lithography patterns.The core principle of this strategy is based on the effect of the size of the groove patterns on quartz etching,whereby trenches of varying depths can be created in a fixed etching time by adjusting the width of the hard mask.Specifically,the device outline and grooved structure can be completed using a seamlessly designed etching pattern and optimized time.Furthermore,the etching structure itself influences the etching results.It was found that dividing a wide trench by including a wall to separate it into two narrow trenches significantly reduces the etching rate,allowing for predictable tuning of the etching rate for wider grooves.This effectively increases the usability and flexibility of the one-step strategy.This was applied to the manufacture of an ultra-small quartz grooved tuning fork resonator with a frequency of 32.768 kHz in a single step,increasing production efficiency by almost 45%and reducing costs by almost 30%compared to current methods.This has great potential for improving the productivity of grooved tuning fork devices.It can also be extended to the fabrication of other quartz crystal devices requiring hierarchical structures.
基金This work was supported by JSPS KAKENHI Grant Number 25286038.
文摘The high-precision integration of three-dimensional(3D)microoptical components into microfluidics in a customizable manner is crucial for optical sensing,fluorescence analysis,and cell detection in optofluidic applications;however,it remains challenging for current microfabrication technologies.This paper reports the in-channel integration of flexible two-dimensional(2D)and 3D polymer microoptical devices into glass microfluidics by developing a novel technique:flat scaffold-supported hybrid femtosecond laser microfabrication(FSS-HFLM).The scaffold with an optimal thickness of 1–5 μm is fabricated on the lower internal surface of a microfluidic channel to improve the integration of high-precision microoptical devices on the scaffold by eliminating any undulated internal channel surface caused by wet etching.As a proof of demonstration,two types of typical microoptical devices,namely,2D Fresnel zone plates(FZPs)and 3D refractive microlens arrays(MLAs),are integrated.These devices exhibit multicolor focal spots,elongated(>three times)focal length and imaging of the characters‘RIKEN’in a liquid channel.The resulting optofluidic chips are further used for coupling-free white-light cell counting with a success rate as high as 93%.An optofluidic system with two MLAs and a W-filter is also designed and fabricated for more advanced cell filtering/counting applications.
文摘This paper presents a simple technique to fabricate new electrofluidic devices for the three-dimensional(3D)manipulation of microorganisms by hybrid subtractive and additive femtosecond(fs)laser microfabrication(fs laser-assisted wet etching of glass followed by water-assisted fs laser modification combined with electroless metal plating).The technique enables the formation of patterned metal electrodes in arbitrary regions in closed glass microfluidic channels,which can spatially and temporally control the direction of electric fields in 3D microfluidic environments.The fabricated electrofluidic devices were applied to nanoaquariums to demonstrate the 3D electro-orientation of Euglena gracilis(an elongated unicellular microorganism)in microfluidics with high controllability and reliability.In particular,swimming Euglena cells can be oriented along the z-direction(perpendicular to the device surface)using electrodes with square outlines formed at the top and bottom of the channel,which is quite useful for observing the motions of cells parallel to their swimming directions.Specifically,z-directional electric field control ensured efficient observation of manipulated cells on the front side(45 cells were captured in a minute in an imaging area of~160×120μm),resulting in a reduction of the average time required to capture the images of five Euglena cells swimming continuously along the z-direction by a factor of~43 compared with the case of no electric field.In addition,the combination of the electrofluidic devices and dynamic imaging enabled observation of the flagella of Euglena cells,revealing that the swimming direction of each Euglena cell under the electric field application was determined by the initial body angle.
文摘This study presents the design,fabrication,and testing of biodegradable magnesium/iron batteries featuring polycaprolactone(PCL)as a packaging and functional material.The use of PCL encapsulation minimized the electrochemical cell volume and supported longer discharge lifetimes and higher discharge rates than state-of-the-art biodegradable batteries.Specifically,the electrodes were separated and insulated by a 5μm-thick PCL layer that served as both a battery packaging material and a permeable coating for physiological solution to penetrate and activate the battery.A systematic investigation of the electrode size,discharge rates,electrolyte selection,and polymeric coating revealed the critical reactions and phenomena governing the performance of the Mg-based biodegradable batteries.Comparison with previous reports on biodegradable batteries and medicalgrade non-degradable lithium-ion batteries demonstrated the superior performance of PCL-coated Mg/Fe batteries at these size scales,which exhibited an energy density of 694 Wh kg^(−1) and a total volume of 0.02 cm^(3).
基金supported by the Natural Science Foundation of China (Grant No.12234005)the major research and development program of Jiangsu Province (Grant Nos.BE2021007-2 and BK20222007)。
文摘Quartz crystals are the most widely used material in resonant sensors,owing to their excellent piezoelectric and mechanical properties.With the development of portable and wearable devices,higher processing efficiency and geometrical precision are required.Wet etching has been proven to be the most efficient etching method for large-scale production of quartz devices,and many wet etching approaches have been developed over the years.However,until now,there has been no systematic review of quartz crystal etching in liquid phase environments.Therefore,this article provides a comprehensive review of the development of wet etching processes and the achievements of the latest research in thisfield,covering conventional wet etching,additive etching,laser-induced backside wet etching,electrochemical etching,and electrochemical discharge machining.For each technique,a brief overview of its characteristics is provided,associated problems are described,and possible solutions are discussed.This review should provide an essential reference and guidance for the future development of processing strategies for the manufacture of quartz crystal devices.
基金supported in part by the National Key Research and Development Plan(2022YFB3203400)the National Natural Science Foundation of China(62103324 and U1909221)the Natural Science Foundation of Shaanxi(2022JQ-554).
文摘Existing microfabricated atomic vapor cells have only one optical channel,which is insufficient for supporting the multiple orthogonal beams required by atomic devices.In this study,we present a novel wafer-level manufacturing process for fabricating multi-optical-channel atomic vapor cells and an innovative method for batch processing the inner sidewalls of millimeter glass holes to meet optical channel requirements.Surface characterization and transmittance tests demonstrate that the processed inner sidewalls satisfy the criteria for an optical channel.In addition,the construction of an integrated processing platform enables multilayer non-isothermal anode bonding,the filling of inert gases,and the recovery and recycling of noble gases.Measurements of the absorption spectra and free-induction decay signals of xenon-129(^(129)Xe)and xenon-131(^(131)Xe)under different pump-probe schemes demonstrate the suitability of our vapor cell for use in atomic devices including atomic gyroscopes,dual-beam atomic magnetometers,and other optical/atomic devices.The proposed micromolding technology has broad application prospects in the field of optical-device processing.
基金supported by National Key Research and Development Program of China(No.2023YFB3210400)Major Scientific and Technological Innovation Project of Shandong Province(No.2021CXGC010603)+1 种基金Natural Science Foundation of Shandong Province(Nos.ZR2020QE057,ZR2020QE071,ZR2020LLZ006)Innovative Team Project of Jinan(No.2021GXRC019)。
文摘Semiconductor-molecule surface-enhanced Raman scattering(SERS),especially the stronger interfacial charge transfer process(ICTP),represents a frontier in the field of SERS with spectral reproducibility and unparalleled selectivity.Herein,through a laser microfabrication method in situ,the free-standing,super hydrophilic and vacancy-rich TiO_(2-x)/Ti is successfully synthesized.Using blue TiO_(x)/Ti(B-TiO_(x)/Ti)as preconcentrated substrate,a nanomolar-level limit of detection of 12 nmol/L at 1385 cm–1,is confirmed using crystal violet(CV)bacteriostat as a model under 532 nm excitation.Furthermore,the results demonstrate that the SERS enhancement mechanism is via the moderate adulteration of oxygen vacancy,which leads to a narrow value of band gap and increases the ICTP of substrate to molecules.Using a hand-held extractor assembled with B-TiO_(x)/Ti microfiber,the operando analysis of mixtures distributed information excited in different parts of Asian carp is facilely achieved.This work guides the controlled synthesis of vacancy-rich TiO_(2-x)/Ti nanostructure and its application in ultrasensitive extraction-SERS detection.It also provides the direction for the rapid and operando transmission of biological information with temporal and spatial concentration distribution in human tissues by highly sensitized materials.
文摘Electrochemical biosensors have emerged as a promising technology for cancer detection due to their high sensitivity,rapid response,low cost,and capability for non-invasive detection.Recent advances in nanomaterials like nanoparticles,graphene,and nanowires have enhanced sensor performance to allow for cancer biomarker detection,like circulating tumor cells,nucleic acids,proteins and metabolites,at ultra-low concentrations.However,several challenges need to be addressed before electrochemical biosensors can be clinically implemented.These include improving sensor selectivity in complex biological media,device miniaturization for implantable applications,integration with data analytics,handling biomarker variability,and navigating regulatory approval.This editorial critically examines the prospects of electrochemical biosensors for efficient,low-cost and minimally invasive cancer screening.We discuss recent developments in nanotechnology,microfabrication,electronics integration,multiplexing,and machine learning that can help realize the potential of these sensors.However,significant interdisciplinary efforts among researchers,clinicians,regulators and the healthcare industry are still needed to tackle limitations in selectivity,size constraints,data interpretation,biomarker validation,toxicity and commercial translation.With committed resources and pragmatic strategies,electrochemical biosensors could enable routine early cancer detection and dramatically reduce the global cancer burden.
文摘A new method is presented,which can obtain high aspect ratio in SU8 structures.Instead that the top of the photo resist layers are exposed to UV light through masks in conventional lithography,the new method utilizes a mask-back exposure technique,i.e.the SU8 resist layer coated on a mask surface (metal patterns on a glass plate),is irradiated by UV light through the back of the mask.So a desired exposure dose on the bottom of the resist layer can be easily achieved without over-exposing from its top.This has a two-fold effect,i.e.proper dose on the bottom of the resist and less internal stress.Initial experimental results show that compared to an aspect ratio of 18 obtained by conventional method,a higher aspect ratio of 32 in the SU8 structures can be achieved by this new method.
基金financial support from the Science and Engineering Research Council,Agency for Science,Technology and Research(A*STAR),Singapore(142 68 00088)
文摘Additive manufacturing(AM)is gaining traction in the manufacturing industry for the fabrication of components with complex geometries using a variety of materials.Selective laser melting(SLM)is a common AM technique that is based on powder-bed fusion(PBF)to process metals;however,it is currently focused only on the fabrication of macroscale and mesoscale components.This paper reviews the state of the art of the SLM of metallic materials at the microscale level.In comparison with the direct writing techniques that are commonly used for micro AM,micro SLM is attractive due to a number of factors,including a faster cycle time,process simplicity,and material versatility.A comprehensive evaluation of various research works and commercial systems for the fabrication of microscale parts using SLM and selective laser sintering(SLS)is conducted.In addition to identifying existing issues with SLM at the microscale,which include powder recoating,laser optics,and powder particle size,this paper details potential future directions.A detailed review of existing recoating methods in powder-bed techniques is conducted,along with a description of emerging efforts to implement dry powder dispensing methods in the AM domain.A number of secondary finishing techniques for AM components are reviewed,with a focus on implementation for microscale features and integration with micro SLM systems.
文摘Nanotechnology allows the realization of new materials and devices with basic structural unit in the range of1–100 nm and characterized by gaining control at the atomic, molecular, and supramolecular level. Reducing the dimensions of a material into the nanoscale range usually results in the change of its physiochemical properties such as reactivity,crystallinity, and solubility. This review treats the convergence of last research news at the interface of nanostructured biomaterials and tissue engineering for emerging biomedical technologies such as scaffolding and tissue regeneration. The present review is organized into three main sections. The introduction concerns an overview of the increasing utility of nanostructured materials in the field of tissue engineering. It elucidates how nanotechnology, by working in the submicron length scale, assures the realization of a biocompatible interface that is able to reproduce the physiological cell–matrix interaction. The second, more technical section, concerns the design and fabrication of biocompatible surface characterized by micro- and submicroscale features, using microfabrication, nanolithography, and miscellaneous nanolithographic techniques.In the last part, we review the ongoing tissue engineering application of nanostructured materials and scaffolds in different fields such as neurology, cardiology, orthopedics, and skin tissue regeneration.
基金the support and funding from China Scholarship Council(CSC)support by the Leibniz Program of the German Research Foundation(SCHM 1298/26-1)。
文摘The rapid development of wearable and portable electronics has dramatically increased the application for miniaturized energy storage components.Stamping micro-supercapacitors(MSCs)with planar interdigital configurations are considered as a promising candidate to meet the requirements.In this review,recent progress of the different stamping materials and various stamping technologies are first discussed.The merits of each material,manufacturing process of each stamping method and the properties of stamping MSCs are scrutinized,respectively.Further insights on technical difficulties and scientific challenges are finally demonstrated,including the limited thickness of printed electrodes,poor overlay accuracy and printing resolution.
