The assessment of mechanical properties is essential across a wide range of scientific and engineering disciplines. Among the available techniques, contact resonance stands out for its sensitivity and resolution. Traditionally associated with atomic force microscopy, this method operates in the nanonewton force range using nanometer-scale tip radii and relies on complex optical detection systems. However, applications involving biological materials, such as plant tissues, might require higher forces, typically in the micronewton range, and larger indenters at the micron scale to minimize local stress. In this work, we present a contact resonance system based on 3D-printed cantilevers designed to operate at micronewton force levels. Both actuation and detection of vibrational modes are achieved using piezoelectric materials, enabling a fully electrical setup that eliminates the need for optical components. The indenters are fabricated from tungsten via electrochemical etching, allowing precise control over tip geometry at the micrometer scale. The system successfully detects frequency shifts upon contact with materials exhibiting elastic moduli from a few to several tens of gigapascals, offering a versatile and cost-effective alternative for mechanical property evaluation.
{"title":"3D-printed piezoelectrically-actuated self-sensing cantilever for contact resonance","authors":"Enrique Sánchez-Gómez, Víctor Ruiz-Díez, Jorge Hernando-García","doi":"10.1016/j.mne.2025.100335","DOIUrl":"10.1016/j.mne.2025.100335","url":null,"abstract":"<div><div>The assessment of mechanical properties is essential across a wide range of scientific and engineering disciplines. Among the available techniques, contact resonance stands out for its sensitivity and resolution. Traditionally associated with atomic force microscopy, this method operates in the nanonewton force range using nanometer-scale tip radii and relies on complex optical detection systems. However, applications involving biological materials, such as plant tissues, might require higher forces, typically in the micronewton range, and larger indenters at the micron scale to minimize local stress. In this work, we present a contact resonance system based on 3D-printed cantilevers designed to operate at micronewton force levels. Both actuation and detection of vibrational modes are achieved using piezoelectric materials, enabling a fully electrical setup that eliminates the need for optical components. The indenters are fabricated from tungsten via electrochemical etching, allowing precise control over tip geometry at the micrometer scale. The system successfully detects frequency shifts upon contact with materials exhibiting elastic moduli from a few to several tens of gigapascals, offering a versatile and cost-effective alternative for mechanical property evaluation.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100335"},"PeriodicalIF":3.1,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently, there has been growing interest in ultrathin polydimethylsiloxane (PDMS) films, which are expected to serve as superior coating materials, offering enhanced surface adhesion and improved thermal conductivity to the surroundings. However, fabricating and patterning PDMS nanofilms using conventional techniques remain particularly challenging. In this study, we demonstrate a method for fabricating micropatterned ultrathin PDMS films less than 100 nm thick on substrates using maskless ultraviolet (UV) lithography. Photocurable PDMS is spin-coated to a thickness of several micrometers and then exposed to UV light with a shallow focal depth. After development with xylene, only the photo-cured PDMS remains on the substrate as an ultrathin film with a thickness ranging from several nanometers to a few hundred nanometers, which can be controlled by adjusting the exposure dose. This technique requires no lift-off or etching processes and offers broad applicability for various PDMS-based devices and systems.
{"title":"Direct fabrication of micropatterned PDMS nanofilms using maskless UV lithography","authors":"Hajime Okamoto , Riku Takahashi , Azusa Oshima , Satoshi Sasaki","doi":"10.1016/j.mne.2025.100329","DOIUrl":"10.1016/j.mne.2025.100329","url":null,"abstract":"<div><div>Recently, there has been growing interest in ultrathin polydimethylsiloxane (PDMS) films, which are expected to serve as superior coating materials, offering enhanced surface adhesion and improved thermal conductivity to the surroundings. However, fabricating and patterning PDMS nanofilms using conventional techniques remain particularly challenging. In this study, we demonstrate a method for fabricating micropatterned ultrathin PDMS films less than 100 nm thick on substrates using maskless ultraviolet (UV) lithography. Photocurable PDMS is spin-coated to a thickness of several micrometers and then exposed to UV light with a shallow focal depth. After development with xylene, only the photo-cured PDMS remains on the substrate as an ultrathin film with a thickness ranging from several nanometers to a few hundred nanometers, which can be controlled by adjusting the exposure dose. This technique requires no lift-off or etching processes and offers broad applicability for various PDMS-based devices and systems.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100329"},"PeriodicalIF":3.1,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145467002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The miniaturization of sensing elements in hot-wire anemometry through micro-fabrication techniques enables high temporal and spatial resolution, essential for investigating complex and high-speed flows. However, hot-wire probes remain inherently intrusive, and minimizing disturbances caused by the probe is critical for accurate measurements at small scales. This study focuses on the development of a micro hot-wire (HW) sensor with reduced disturbances through the implementation of a streamlined geometry. By developing a micro-fabrication process, based among others on silicon’s aspect ratio-dependent etching properties, a new sensor prototype was produced. Experimental characterization in a wall-bounded flow highlights the potential and limitations of this streamlined design for aerodynamic applications.
{"title":"Fabrication and characterization of a streamlined micro hot wire probe to reduce aerodynamic disturbances","authors":"Baptiste Baradel , Olivier Léon , Léo Chamard , Philippe Combette , Fabien Méry , Alain Giani","doi":"10.1016/j.mne.2025.100326","DOIUrl":"10.1016/j.mne.2025.100326","url":null,"abstract":"<div><div>The miniaturization of sensing elements in hot-wire anemometry through micro-fabrication techniques enables high temporal and spatial resolution, essential for investigating complex and high-speed flows. However, hot-wire probes remain inherently intrusive, and minimizing disturbances caused by the probe is critical for accurate measurements at small scales. This study focuses on the development of a micro hot-wire (<span><math><mrow><mi>x</mi><mi>μ</mi></mrow></math></span>HW) sensor with reduced disturbances through the implementation of a streamlined geometry. By developing a micro-fabrication process, based among others on silicon’s aspect ratio-dependent etching properties, a new sensor prototype was produced. Experimental characterization in a wall-bounded flow highlights the potential and limitations of this streamlined design for aerodynamic applications.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100326"},"PeriodicalIF":3.1,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-21DOI: 10.1016/j.mne.2025.100328
Liline A.S. Fermin , Daniel de Melo Pereira , Maryam Parvizifard , Noel L. Davison , Elizabeth R. Balmayor , Huipin Yuan , Pamela Habibović , Zeinab Niloofar Tahmasebi Birgani
Biomaterial surface topography can modulate cellular behavior and has become a powerful tool for developing highly functional biomaterials for tissue regeneration applications. For example, grained topographies in the microstructure of calcium phosphate ceramics, such as β-tricalcium phosphates (TCPs), were shown to impact their osteoinductive properties; yet the mechanisms of action underlying interactions of these surface topographies with cells are not fully understood. Probing these types of biological mechanisms is especially challenging because of the combined effects of biomaterial surface chemistry and topography, which are difficult to deconvolute. Previously, hot embossing with an inversely replicated polydimethylsiloxane (PDMS) mold was employed to transfer the topographies of TCPs onto polymer films and investigate their cell-instructive effects independent of the substrate chemistry. This method proved successful for copying the surficial topographies of the ceramics to the polymer substrates. Here, we describe an improved replication method using nickel mold galvanoforming and nanoimprinting to create high-fidelity replicas of micro- and sub-micro-sized topographies of TCPs in thermoplastic polyurethane (TPU). Our findings indicate that using the proposed method, the topography replication depth was greatly improved in both the intermediate molds and the TPU imprints of the TCPs compared to hot embossing method with PDMS mold. This method is particularly suitable for replicating complex, naturally occurring surface topographies onto different polymer films and allows for the reliable investigation of the role of micro- and sub-micro-sized topographies on cell behavior, as well as for developing highly functional biomaterials.
{"title":"A method for accurate replication of complex and cell-instructive surface microtopographies","authors":"Liline A.S. Fermin , Daniel de Melo Pereira , Maryam Parvizifard , Noel L. Davison , Elizabeth R. Balmayor , Huipin Yuan , Pamela Habibović , Zeinab Niloofar Tahmasebi Birgani","doi":"10.1016/j.mne.2025.100328","DOIUrl":"10.1016/j.mne.2025.100328","url":null,"abstract":"<div><div>Biomaterial surface topography can modulate cellular behavior and has become a powerful tool for developing highly functional biomaterials for tissue regeneration applications. For example, grained topographies in the microstructure of calcium phosphate ceramics, such as β-tricalcium phosphates (TCPs), were shown to impact their osteoinductive properties; yet the mechanisms of action underlying interactions of these surface topographies with cells are not fully understood. Probing these types of biological mechanisms is especially challenging because of the combined effects of biomaterial surface chemistry and topography, which are difficult to deconvolute. Previously, hot embossing with an inversely replicated polydimethylsiloxane (PDMS) mold was employed to transfer the topographies of TCPs onto polymer films and investigate their cell-instructive effects independent of the substrate chemistry. This method proved successful for copying the surficial topographies of the ceramics to the polymer substrates. Here, we describe an improved replication method using nickel mold galvanoforming and nanoimprinting to create high-fidelity replicas of micro- and sub-micro-sized topographies of TCPs in thermoplastic polyurethane (TPU). Our findings indicate that using the proposed method, the topography replication depth was greatly improved in both the intermediate molds and the TPU imprints of the TCPs compared to hot embossing method with PDMS mold. This method is particularly suitable for replicating complex, naturally occurring surface topographies onto different polymer films and allows for the reliable investigation of the role of micro- and sub-micro-sized topographies on cell behavior, as well as for developing highly functional biomaterials.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100328"},"PeriodicalIF":3.1,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-13DOI: 10.1016/j.mne.2025.100327
Shi-Li Zhang
Quantum computing has been envisioned to offer unprecedented advantages over conventional supercomputers in certain computational applications such as drug discovery and materials design. Despite of the tremendous developments in recent years, concerns about building a practical quantum computer persist. This Letter examines, from engineering viewpoint, the grand challenges to building such a machine based on the leading technology platform “transmon”. The examination leads to proposal of technological solutions to break the scalability barriers that originate from the physics behind the transmon design, thereby to enable giga-scale integration necessary for the promised applications.
{"title":"Scalability analysis for transmon-based quantum computers","authors":"Shi-Li Zhang","doi":"10.1016/j.mne.2025.100327","DOIUrl":"10.1016/j.mne.2025.100327","url":null,"abstract":"<div><div>Quantum computing has been envisioned to offer unprecedented advantages over conventional supercomputers in certain computational applications such as drug discovery and materials design. Despite of the tremendous developments in recent years, concerns about building a practical quantum computer persist. This <em>Letter</em> examines, from engineering viewpoint, the grand challenges to building such a machine based on the leading technology platform “transmon”. The examination leads to proposal of technological solutions to break the scalability barriers that originate from the physics behind the transmon design, thereby to enable giga-scale integration necessary for the promised applications.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100327"},"PeriodicalIF":3.1,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.mne.2025.100325
Suhyun Park , Soobin Sim , Hyeonjun Lee , Hak June Lee , Jeong Woo Park , Jin Su Park , Wan Ki Bae , Hyunkoo Lee
The efficiency of quantum-dot light-emitting diodes (QLEDs) was improved by utilizing a microlens array (MLA) film, and the effect of the MLA film was investigated through optical simulation. The MLA films enhanced luminance by 1.51 and 1.28 times at 5 V for green and red QLEDs, respectively. The green and red QLEDs exhibited high external quantum efficiencies of 14.69 % and 19.87 %, and efficiency enhancement ratios were approximately 56.97 % and 21.68 %, respectively. Furthermore, the electroluminescence spectra remained stable, ensuring color consistency. By altering the dipole orientation of the emitter in the optical simulation, we observed that as the dipole became more vertical, the efficiency improved due to increased light extraction by the MLA. In addition, varying the number of microlens array by changing the microlens radius in the same emission area resulted in a consistent enhancement ratio, while increasing the MLA density significantly improved light extraction. These results suggest that MLA films effectively enhance the efficiency of QLEDs with color stability, providing a strategy for improving their performance.
{"title":"Effect of microlens arrays on light extraction efficiency in red and green quantum-dot light-emitting diodes","authors":"Suhyun Park , Soobin Sim , Hyeonjun Lee , Hak June Lee , Jeong Woo Park , Jin Su Park , Wan Ki Bae , Hyunkoo Lee","doi":"10.1016/j.mne.2025.100325","DOIUrl":"10.1016/j.mne.2025.100325","url":null,"abstract":"<div><div>The efficiency of quantum-dot light-emitting diodes (QLEDs) was improved by utilizing a microlens array (MLA) film, and the effect of the MLA film was investigated through optical simulation. The MLA films enhanced luminance by 1.51 and 1.28 times at 5 V for green and red QLEDs, respectively. The green and red QLEDs exhibited high external quantum efficiencies of 14.69 % and 19.87 %, and efficiency enhancement ratios were approximately 56.97 % and 21.68 %, respectively. Furthermore, the electroluminescence spectra remained stable, ensuring color consistency. By altering the dipole orientation of the emitter in the optical simulation, we observed that as the dipole became more vertical, the efficiency improved due to increased light extraction by the MLA. In addition, varying the number of microlens array by changing the microlens radius in the same emission area resulted in a consistent enhancement ratio, while increasing the MLA density significantly improved light extraction. These results suggest that MLA films effectively enhance the efficiency of QLEDs with color stability, providing a strategy for improving their performance.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100325"},"PeriodicalIF":3.1,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-02DOI: 10.1016/j.mne.2025.100324
Mohammad Ramezannezhad, Babak Rezaei, Stephan Sylvest Keller
This study presents the optimization of maskless UV lithography with SU-8 for the fabrication of 3D electrodes with pyrolytic carbon micropillar arrays. The aim was to maximize the pillar density and enhance the electroactive surface area of the electrodes. For this purpose, the exposure dose at 365 nm wavelength and defocus value in a maskless aligner projecting the image with a spatial light modulator onto the substrate were optimized for fabrication of SU-8 micropillars with heights varying from 25 to 100 μm and diameters ranging from 5 to 40 μm resulting in aspect-ratio of up to 10. The minimal achievable gap in SU-8 micropillar arrays was largely dependent on the defocus value, and gap dimensions identical to the pillar diameter were achieved. The SU-8 precursor structures were successfully converted into carbon micropillar arrays by pyrolysis at 1050 °C with an observed shrinkage of approximately 50 %. 3D carbon microelectrodes were fabricated and electrochemically characterized with cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that there is a reasonable correlation between microelectrode surface area and electrochemical performance of the electrodes. 3D electrodes with less dense arrays of larger pillars fabricated with initial SU-8 height of 75 μm and 100 μm showed higher peak currents in cyclic voltammetry than smaller pillars at higher number densities, reaching a maximum enhancement of approximately a factor 2 compared to 2D electrodes without micropillars.
{"title":"Optimization of maskless SU-8 photolithography for fabrication of dense high-aspect-ratio pyrolytic carbon micropillar arrays","authors":"Mohammad Ramezannezhad, Babak Rezaei, Stephan Sylvest Keller","doi":"10.1016/j.mne.2025.100324","DOIUrl":"10.1016/j.mne.2025.100324","url":null,"abstract":"<div><div>This study presents the optimization of maskless UV lithography with SU-8 for the fabrication of 3D electrodes with pyrolytic carbon micropillar arrays. The aim was to maximize the pillar density and enhance the electroactive surface area of the electrodes. For this purpose, the exposure dose at 365 nm wavelength and defocus value in a maskless aligner projecting the image with a spatial light modulator onto the substrate were optimized for fabrication of SU-8 micropillars with heights varying from 25 to 100 μm and diameters ranging from 5 to 40 μm resulting in aspect-ratio of up to 10. The minimal achievable gap in SU-8 micropillar arrays was largely dependent on the defocus value, and gap dimensions identical to the pillar diameter were achieved. The SU-8 precursor structures were successfully converted into carbon micropillar arrays by pyrolysis at 1050 °C with an observed shrinkage of approximately 50 %. 3D carbon microelectrodes were fabricated and electrochemically characterized with cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that there is a reasonable correlation between microelectrode surface area and electrochemical performance of the electrodes. 3D electrodes with less dense arrays of larger pillars fabricated with initial SU-8 height of 75 μm and 100 μm showed higher peak currents in cyclic voltammetry than smaller pillars at higher number densities, reaching a maximum enhancement of approximately a factor 2 compared to 2D electrodes without micropillars.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100324"},"PeriodicalIF":3.1,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-29DOI: 10.1016/j.mne.2025.100323
Tapio Mäkelä, Asko Sneck, Olli Halonen, Ari Hokkanen, Kim Eiroma, Jaakko Leppäniemi
We demonstrate a manufacturing process for a transparent metal mesh heater using reverse offset printing (ROP), metal lift-off and Ni electroplating. All used methods are scalable and compatible with high-throughput roll-to-roll (R2R) fabrication. First, a Cu-mesh seed layer is produced by ROP printing of a ∼ 70 nm thick semi-dry poly 4-vinylphenol (PVPh) ink on polyethylene terephthalate (PET) substrate and followed by metal evaporation and a lift-off process using the patterned PVPh as a mask. After this, the thickness of the relatively thin Cu-mesh (40 nm) is increased using a Ni-electroplating process to achieve the desired resistivity (< 3 Ω/□) and metal thickness (1–5 μm) of the heater. Optical transparency of the metal heater is achieved by suitable design and a low linewidth (2 μm) of the ROP/lift-off patterned seed Cu-mesh. The performance of the transparent heater is evaluated e.g. by using a figure of merit (FoM) value and compared against indium tin oxide (ITO) based heaters on PET substrate with a sheet resistance of 50 Ω/□. The FoM value is ∼400 for 4.5 cm × 4.5 cm size heaters, compared to ∼50 for the reference ITO. Four different sized heaters are fabricated and tested with a constant voltage until the temperature of the heater is saturated, yielding >260 °C∙cm2/W thermal resistance, thus much higher than 68 °C∙cm2/W obtained for the ITO reference. The measured optical transparency of ∼74 % of the metal heater is close to the calculated transparency of 77 %. The transparency of the metal mesh is impacted by the relatively high ∼15 % haze, which is probably due to the high surface roughness of Ni. For ITO reference, the transparency and haze are ∼85 % and 1 %, respectively. The operation of the metal mesh heater is demonstrated in a defogging test where water vapor was removed from poly(methyl methacrylate) (PMMA) surface within 10 s of activating the heater. The heater uses relative low voltage (2.5 V) resulting in a surface temperature ∼ 50 °C. The ROP lift-off process produces superior quality of the Cu-seed layer at low-temperature, enables high transparency, allows the use of complex designs and a variety of substrates. The results indicate that the proposed metal mesh heater is a good candidate for scalable, high-volume manufacturing.
{"title":"Scalable transparent metal mesh heater on flexible substrate prepared using reverse-offset printed seed layer","authors":"Tapio Mäkelä, Asko Sneck, Olli Halonen, Ari Hokkanen, Kim Eiroma, Jaakko Leppäniemi","doi":"10.1016/j.mne.2025.100323","DOIUrl":"10.1016/j.mne.2025.100323","url":null,"abstract":"<div><div>We demonstrate a manufacturing process for a transparent metal mesh heater using reverse offset printing (ROP), metal lift-off and Ni electroplating. All used methods are scalable and compatible with high-throughput roll-to-roll (R2R) fabrication. First, a Cu-mesh seed layer is produced by ROP printing of a ∼ 70 nm thick semi-dry poly 4-vinylphenol (PVPh) ink on polyethylene terephthalate (PET) substrate and followed by metal evaporation and a lift-off process using the patterned PVPh as a mask. After this, the thickness of the relatively thin Cu-mesh (40 nm) is increased using a Ni-electroplating process to achieve the desired resistivity (< 3 Ω/□) and metal thickness (1–5 μm) of the heater. Optical transparency of the metal heater is achieved by suitable design and a low linewidth (2 μm) of the ROP/lift-off patterned seed Cu-mesh. The performance of the transparent heater is evaluated e.g. by using a figure of merit (FoM) value and compared against indium tin oxide (ITO) based heaters on PET substrate with a sheet resistance of 50 Ω/□. The FoM value is ∼400 for 4.5 cm × 4.5 cm size heaters, compared to ∼50 for the reference ITO. Four different sized heaters are fabricated and tested with a constant voltage until the temperature of the heater is saturated, yielding >260 °C<strong>∙</strong>cm<sup>2</sup>/W thermal resistance, thus much higher than 68 °C<strong>∙</strong>cm<sup>2</sup>/W obtained for the ITO reference. The measured optical transparency of ∼74 % of the metal heater is close to the calculated transparency of 77 %. The transparency of the metal mesh is impacted by the relatively high ∼15 % haze, which is probably due to the high surface roughness of Ni. For ITO reference, the transparency and haze are ∼85 % and 1 %, respectively. The operation of the metal mesh heater is demonstrated in a defogging test where water vapor was removed from poly(methyl methacrylate) (PMMA) surface within 10 s of activating the heater. The heater uses relative low voltage (2.5 V) resulting in a surface temperature ∼ 50 °C. The ROP lift-off process produces superior quality of the Cu-seed layer at low-temperature, enables high transparency, allows the use of complex designs and a variety of substrates. The results indicate that the proposed metal mesh heater is a good candidate for scalable, high-volume manufacturing.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100323"},"PeriodicalIF":3.1,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-21DOI: 10.1016/j.mne.2025.100322
C. Laurini , E. La Civita , E. Battista , V. Mollo , B. Della Ventura , R. Velotta , D. Terracciano , M.L. Coluccio , F. Gentile
Prostate-specific antigen (PSA) is a crucial biomarker for the early detection and monitoring of prostate cancer (PC). In this study, we present a biosensing approach that integrates plasmonic nanostructures with surface-enhanced Raman spectroscopy (SERS) for the ultrasensitive detection of PSA in diluted solution. Our sensor device consists of ordered arrays of densely packed gold nanoparticles (Au NPs), fabricated using a combination of optical-lithography and electroless deposition techniques. The plasmonic properties of the Au NPs enhance the Raman scattering effect, significantly improving sensitivity and detection limits. We demonstrate the device's capability to detect PSA at vanishingly low concentrations – as low as - well below the 4 ng/mL threshold used in clinical practice. Data analysis of Raman spectra illustrate that the response of the sensor device to PSA exhibits two distinct, approximately linear regimes. In the first regime (I), the Raman intensity increases with PSA concentration. In the second regime (II), the intensity decreases as concentration continues to rise. The transition between these regimes occurs at around . The existence of these regimes is explained by the peculiar behavior of surface enhanced Raman substrates, where the signal intensity non-linearly depends on the distance from the active metal nano-surface. At higher PSA concentrations, the biomarker may accumulate on the Au NPs, hampering the efficiency of sensing. These findings suggest that this plasmonic-SERS platform could provide a highly effective, non-invasive tool for PSA detection, potentially improving PC diagnostics.
{"title":"Enhanced detection of PSA by nanoscale plasmonic devices and Raman spectroscopy","authors":"C. Laurini , E. La Civita , E. Battista , V. Mollo , B. Della Ventura , R. Velotta , D. Terracciano , M.L. Coluccio , F. Gentile","doi":"10.1016/j.mne.2025.100322","DOIUrl":"10.1016/j.mne.2025.100322","url":null,"abstract":"<div><div>Prostate-specific antigen (PSA) is a crucial biomarker for the early detection and monitoring of prostate cancer (PC). In this study, we present a biosensing approach that integrates plasmonic nanostructures with surface-enhanced Raman spectroscopy (SERS) for the ultrasensitive detection of PSA in diluted solution. Our sensor device consists of ordered arrays of densely packed gold nanoparticles (Au NPs), fabricated using a combination of optical-lithography and electroless deposition techniques. The plasmonic properties of the Au NPs enhance the Raman scattering effect, significantly improving sensitivity and detection limits. We demonstrate the device's capability to detect PSA at vanishingly low concentrations – as low as <span><math><mn>38</mn><mspace></mspace><mi>pg</mi><mo>/</mo><mi>mL</mi></math></span> - well below the 4 ng/mL threshold used in clinical practice. Data analysis of Raman spectra illustrate that the response of the sensor device to PSA exhibits two distinct, <em>approximately linear</em> regimes. In the first regime (I), the Raman intensity increases with PSA concentration. In the second regime (II), the intensity decreases as concentration continues to rise. The transition between these regimes occurs at around <span><math><mn>3</mn><mspace></mspace><mi>ng</mi><mo>/</mo><mi>mL</mi></math></span>. The existence of these regimes is explained by the peculiar behavior of surface enhanced Raman substrates, where the signal intensity non-linearly depends on the distance from the active metal nano-surface. At higher PSA concentrations, the biomarker may accumulate on the Au NPs, hampering the efficiency of sensing. These findings suggest that this plasmonic-SERS platform could provide a highly effective, non-invasive tool for PSA detection, potentially improving PC diagnostics.</div></div>","PeriodicalId":37111,"journal":{"name":"Micro and Nano Engineering","volume":"29 ","pages":"Article 100322"},"PeriodicalIF":3.1,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145120575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-12DOI: 10.1016/j.mne.2025.100320
S.N. Ghosh, S. Talukder
Photolithography is the most widely used lithography technique for commercial fabrication of micro-devices as well as for research and development purposes. However, to perform photolithography, we need a photomask containing the desired pattern. Conventional methods of photomask fabrication involve either photolithography using a direct laser writer or electron-beam lithography. Interestingly, the rise of sequential write scanning probe lithography (SPL) techniques has given rise to various novel methods of direct photomask writing. In this study, we focus on photomask fabrication using a SPL technique, known as ‘Electrolithography’ (ELG), with which multi-scale features can be easily patterned. This is a subtractive lithography technique that involves direct patterning on chromium (Cr) thin films. Being an electrical and direct-write process, ELG bypasses the need for high-power UV laser, electron gun, and polymer resist layers thereby making the process cost-effective and carbon-efficient. We propose a resistless, reliable and novel photomask fabrication process, using the ELG technique, based on a bimetallic architecture. Using the proposed method, we were able to obtain lines having a width of <2 μm, in the best case, and lines with a width < 10 μm repeatedly. We were also able to transfer the fabricated patterns reliably and repeatedly onto a material of choice.
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