Small Intercondylar Notch Size Is Not Associated with Poor Surgical Outcomes of Anatomical Single-Bundle Anterior Cruciate Ligament Reconstructions.

Background: Although many studies have been conducted on the association between the intercondylar notch size and the risk of anterior cruciate ligament (ACL) injury, few studies have examined its relationship with the condition after surgical treatment. Therefore, this study aimed to investigate the surgical outcomes of anatomical single-bundle ACL reconstruction according to intercondylar notch volumes. Methods: Medical records of patients who underwent anatomical single-bundle ACL reconstruction using a tibialis anterior allograft between 2015 and 2019 were retrospectively reviewed. For each sex, eligible patients were classified into two groups based on their percentile of intercondylar notch volumes, which were measured using postoperative three-dimensional computed tomography images (group S, ≤ 50th percentile of included patients; group L, > 50th percentile of included patients). Additional grouping was performed based on the group's percentiles of normalized values of intercondylar notch volumes to body heights. Between-group comparative analyses were performed on the perioperative data and surgical outcomes in both objective and subjective aspects. Results: One hundred patients were included in the study. For male patients, there were no differences in the overall surgical outcomes between groups, whereas group L showed a significantly greater knee anteroposterior (AP) laxity than group S at the final follow-up (p = 0.042 for the side-to-side differences [SSD] at the maximum manual force). Similarly, there were no differences in the female patients in the overall surgical results between the groups, whereas group L showed a significantly greater knee AP laxity at the final follow-up (p = 0.020 for the SSD at 134 N; p = 0.011 for the SSD at the maximum manual force). Additional analyses based on the normalized values of the intercondylar notch volume showed consistent results for male patients, and additional grouping for female patients was identical to the existing grouping. Conclusions: The surgical outcomes of anatomical single-bundle ACL reconstruction in patients with relatively small intercondylar notch volumes were comparable to those with large notch volumes, but rather showed favorable outcomes in postoperative knee AP laxity.

Ferroelectric 2D SnS2 Analog Synaptic FET.

In this study, the development and characterization of 2D ferroelectric field-effect transistor (2D FeFET) devices are presented, utilizing nanoscale ferroelectric HfZrO2 (HZO) and 2D semiconductors. The fabricated device demonstrated multi-level data storage capabilities. It successfully emulated essential biological characteristics, including excitatory/inhibitory postsynaptic currents (EPSC/IPSC), Pair-Pulse Facilitation (PPF), and Spike-Timing Dependent Plasticity (STDP). Extensive endurance tests ensured robust stability (107 switching cycles, 105 s (extrapolated to 10 years)), excellent linearity, and high Gmax/Gmin ratio (>105), all of which are essential for realizing multi-level data states (>7-bit operation). Beyond mimicking synaptic functionalities, the device achieved a pattern recognition accuracy of ≈94% on the Modified National Institute of Standards and Technology (MNIST) handwritten dataset when incorporated into a neural network, demonstrating its potential as an effective component in neuromorphic systems. The successful implementation of the 2D FeFET device paves the way for the development of high-efficiency, ultralow-power neuromorphic hardware which is in sub-femtojoule (48 aJ/spike) and fast response (1 µs), which is 104 folds faster than human synapse (≈10 ms). The results of the research underline the potential of nanoscale ferroelectric and 2D materials in building the next generation of artificial intelligence technologies.

Laser-Induced and MOF-Derived Metal Oxide/Carbon Composite for Synergistically Improved Ethanol Sensing at Room temperature.

Advancements in sensor technology have significantly enhanced atmospheric monitoring. Notably, metal oxide and carbon (MOx/C) hybrids have gained attention for their exceptional sensitivity and room-temperature sensing performance. However, previous methods of synthesizing MOx/C composites suffer from problems, including inhomogeneity, aggregation, and challenges in micropatterning. Herein, we introduce a refined method that employs a metal-organic framework (MOF) as a precursor combined with direct laser writing. The inherent structure of MOFs ensures a uniform distribution of metal ions and organic linkers, yielding homogeneous MOx/C structures. The laser processing facilitates precise micropatterning (< 2 µm, comparable to typical photolithography) of the MOx/C crystals. The optimized MOF-derived MOx/C sensor rapidly detected ethanol gas even at room temperature (105 and 18 s for response and recovery, respectively), with a broad range of sensing performance from 170 to 3,400 ppm and a high response value of up to 3,500%. Additionally, this sensor exhibited enhanced stability and thermal resilience compared to previous MOF-based counterparts. This research opens up promising avenues for practical applications in MOF-derived sensing devices.

Ductile Effect of PGA/PCL Blending Plastics Using a Novel Ionic Chain Extender with Non-Covalent Bonds.

Polyglycolic acid (PGA) is a promising polymer in the packaging field owing to its excellent hydrolysis, heat resistance, and gas barrier properties, but it is limited in application due to its poor toughness. For this reason, a covalently bonded chain extender is introduced to increase compatibility with flexible polymers. However, covalent bonds are unfavorable for application to degradable plastics because of the energy required for reverse reactions. Therefore, we intended to effectively control the ductility of blending plastics by using a novel ionic chain extender with a relatively weaker non-covalent bond than the existing covalent bond. Polycaprolactone (PCL), which has biodegradability and flexibility, was selected as a blending polymer. For comparison, a covalently reactive chain extender (G-CE) and a non-covalently ionic chain extender (D-CE) were synthesized and compounded with blending plastics. Each chain extender improved the compatibility between PGA and PCL, and the ductility of the PGA/PCL blending plastics was more greatly enhanced with non-covalently bonded D-CE than with covalently bonded G-CE. At this time, the ductility of the PGA/PCL(90/10) blending plastic without CE was 7.2%, the ductility of blending plastic with D-CE (10D) was 26.6%, and the ductility of blending plastic with G-CE (10G) was 18.6%. Therefore, it was confirmed that the novel ionic chain extender inducing non-covalent bonds improves the compatibility between PGA and PCL and is more advantageous in enhancing ductility through a reversible reaction.

Semiconducting MOFs on ultraviolet laser-induced graphene with a hierarchical pore architecture for NO2 monitoring.

Due to rapid urbanization worldwide, monitoring the concentration of nitrogen dioxide (NO2), which causes cardiovascular and respiratory diseases, has attracted considerable attention. Developing real-time sensors to detect parts-per-billion (ppb)-level NO2 remains challenging due to limited sensitivity, response, and recovery characteristics. Herein, we report a hybrid structure of Cu3HHTP2, 2D semiconducting metal-organic frameworks (MOFs), and laser-induced graphene (LIG) for high-performance NO2 sensing. The unique hierarchical pore architecture of LIG@Cu3HHTP2 promotes mass transport of gas molecules and takes full advantage of the large surface area and porosity of MOFs, enabling highly rapid and sensitive responses to NO2. Consequently, LIG@Cu3HHTP2 shows one of the fastest responses and lowest limit of detection at room temperature compared with state-of-the-art NO2 sensors. Additionally, by employing LIG as a growth platform, flexibility and patterning strategies are achieved, which are the main challenges for MOF-based electronic devices. These results provide key insight into applying MOFtronics as high-performance healthcare devices.

Inkjet-Printed Polyelectrolyte Seed Layer-Based, Customizable, Transparent, Ultrathin Gold Electrodes and Facile Implementation of Photothermal Effect.

Recently, interest in transparent electrodes has been increasing in biomedical engineering applications for such as electro-optical hybrid neuro-technologies. However, conventional photolithography-based electrode fabrication methods have limited design customization and large-area applicability. For biomedical engineering applications, it is crucial that we can easily customize the electrode design for different patients over a large body area. In this paper, we propose a novel method to fabricate customization-friendly, transparent, ultrathin, gold microelectrodes using inkjet printing technology. Unlike with typical direct printing of conductive inks, we inkjet-printed a polymer nucleation-inducing seed layer, followed by mask-less vacuum deposition of ultrathin gold (<6 nm) to produce selectively, high-transparency electrodes in the predefined shapes of the inkjet-printed polymer. Owing to the design flexibility of inkjet printing, the transparent ultrathin gold electrodes can be highly efficient in design customization over a large area. Simultaneously, a layer of nonconductive gold islands is formed in the nonprinted region, and this nanostructured layer can implement a photothermal effect that offers versatility for novel biomedical applications. As a demonstration of the effectiveness of these transparent electrodes, and the facile implementation of the photothermal effect for biomedical applications, we successfully fabricated transparent resistive temperature detectors. We used these to directly sense the photothermal effect and to demonstrate their bioimaging capabilities.

Outpatient-based diagnostic criteria for partial ACL injury: clinical outcomes of non-operative treatment and radiographic predictor.

INTRODUCTION: This study aimed to (1) evaluate the short-term clinical outcomes of patients who underwent non-operative treatment for partial anterior cruciate ligament (ACL) tears diagnosed using the outpatient-based diagnostic criteria and (2) investigate the radiographic predictors distinguishing patients at risk of non-operative treatment failure. METHODS: From 2010 to 2019, patients diagnosed with partial ACL tears and treated with non-operative treatment were reviewed retrospectively. Patients were then classified into two groups: those who successfully responded to non-operative treatment (group S) and those who failed to respond to non-operative treatment and required surgical reconstruction within 6 months after injury (group F). ACL laxity, patient-reported outcomes (PROs), and several radiographic parameters were analyzed. To identify radiographic predictors related to clinical outcomes, radiographic parameters were compared between the groups, which were statistically matched for potential confounders (age and activity level) using inverse probability of treatment weighting. RESULTS: A total of 44 patients were analyzed (mean age, 28.7 ± 8.7 years; 31 men), and classified into two groups (group S, 23 patients; group F, 21 patients). There were no significant differences in ACL laxity and PROs between the groups at 1 year after either non-operative treatment or surgical reconstruction. A comparison of radiographic parameters between the groups revealed significant differences in several parameters related to secondary signs of ACL injury. Subsequent regression analyses revealed that anterior tibial translation and extent of bone bruises were radiographic predictors related to clinical outcomes. CONCLUSION: Non-operative treatment for partial ACL tears diagnosed using the outpatient-based diagnostic criteria can provide successful short-term clinical outcomes in selective patients. Secondary signs of ACL injuries, particularly the amount of anterior tibial translation and the extent of bone bruises, are radiographic predictors that could differentiate patients at risk of non-operative treatment failure. LEVEL OF EVIDENCE: Retrospective cohort study, III.

Solid-State Synthesis of Cobalt/NCS Electrocatalyst for Oxygen Reduction Reaction in Dual Chamber Microbial Fuel Cells.

Due to the high cost of presently utilized Pt/C catalysts, a quick and sustainable synthesis of electrocatalysts made of cost-effective and earth-abundant metals is urgently needed. In this work, we demonstrated a mechanochemically synthesized cobalt nanoparticles supported on N and S doped carbons derived from a solid-state-reaction between zinc acetate and 2-amino thiazole as metal, organic ligand in presence of cobalt (Co) metal ions ZnxCox(C3H4N2S). Pyrolysis of the ZnxCox(C3H4N2S) produced, Co/NSC catalyst in which Co nanoparticles are evenly distributed on the nitrogen and sulfur doped carbon support. The Co/NSC catalyst have been characterized with various physical and electrochemical characterization techniques. The Co content in the ZnxCox(C3H4N2S) is carefully adjusted by varying the Co content and the optimized Co/NSC-3 catalyst is subjected to the oxygen reduction reaction in 0.1 M HClO4 electrolyte. The optimized Co/NSC-3 catalyst reveals acceptable ORR activity with the half-wave potential of ~0.63 V vs. RHE in acidic electrolytes. In addition, the Co/NSC-3 catalyst showed excellent stability with no loss in the ORR activity after 10,000 potential cycles. When applied as cathode catalysts in dual chamber microbial fuel cells, the Co/NCS catalyst delivered satisfactory volumetric power density in comparison with Pt/C.

Channel Scaling Dependent Photoresponse of Copper-Based Flexible Photodetectors Fabricated Using Laser-Induced Oxidation.

Copper (Cu) oxide compounds (CuxO), which include cupric (CuO) and cuprous (Cu2O) oxide, have been recognized as a promising p-channel material with useful photovoltaic properties and superior thermal conductivity. Typically, deposition methods or thermal oxidation can be used to obtain CuxO. However, these processes are difficult to apply to flexible substrates because plastics have a comparatively low glass transition temperature. Also, additional patterning steps are needed to fabricate applications. In this work, we fabricated a metal-semiconductor-metal photodetector using laser-induced oxidation of thin Cu films under ambient conditions. Raman spectroscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and atomic force microscopy were used to study the composition and morphology of our devices. Moreover, the photoresponse of this device is reported herein. We performed an in-depth analysis of the relationship between the channel size and number of carriers using scanning photocurrent microscopy. The carrier transport behaviors were identified; the photocurrent decreased as the length and width of the channel increased. Furthermore, we verified the suitability of the device as a flexible photodetector using a variety of bending tests. Our in-depth analysis of this Cu-based flexible photodetector could play an important role in understanding the mechanisms of other flexible photovoltaic applications.

The Valid Diagnostic Parameters in Bilateral CT Scan to Predict Unstable Syndesmotic Injury with Ankle Fracture.

The purpose of this study is to evaluate the reasonable parameters to predict unstable syndesmotic injuries in ankle fractures. Seventy consecutive patients who underwent preoperative bilateral computed tomography (CT) scans were enrolled. Group A consisted of 20 patients intraoperatively diagnosed with syndesmotic injuries according to an intraoperative stress test and group B consisted of 50 patients who had nosyndesmotic injuries. The tibiofibular overlap (TFO) and tibiofibular clear space (TFCS) were measured using preoperative ankle radiographs. Measuring the anterior fibular distance (AFD), posterior fibular distance (PFD), anterior translation distance (AT), fibular diastasis (FD), anterior-posterior translation (APT), fibular length (FL), and surface area of syndesmosis (SAS) 1.0 and 1.5 which 1.0 cm and 1.5 cm above the tibial plafond was done via preoperative CT scan. The ratio of measurements (Injured/Intact) of the TFO, PFD, APD, and SAS 1.0 showed statistically significant differences. The researchers identified the SAS 1.0 as the most reasonable parameter to predict transfixation using receiver-operating characteristic (ROC) curve analysis. The SAS 1.0 is most valid parameter to predict syndesmotic injuries in this study and these results show that performing a bilateral CT scan on an ankle fracture may provide substantial information in measuring valid parameters.

Thermoplasmonic Optical Fiber for Localized Neural Stimulation.

Thermoplasmonic effect-based neural stimulation has been suggested as an alternative optical neural stimulation technology without genetic modification. Integration of near-infrared light with plasmonic gold nanoparticles has been demonstrated as a neuromodulation tool on in vitro neuronal network models. In order to further test the validity of the thermoplasmonic neural stimulation across multiple biological models (in vitro, ex vivo, and in vivo) avoiding genetic modification in optical neuromodulation, versatile engineering approaches to apply the thermoplasmonic effect would be required. In this work, we developed a gold nanorod attached optical fiber technology for the localized neural stimulation based on a thermoplasmonic effect. A simple fabrication process was developed for efficient nanoparticle coating on commercial optical fibers. The thermoplasmonic optical fiber proved that it can locally modulate the neural activity in vitro. Lastly, we simulated the spatiotemporal temperature change by the thermoplasmonic optical fiber and analyzed its applicability to in vivo animal models.

Clinical Characteristics of Mitochondrial DNA Copy Number in Osteonecrosis of the Femoral Head.

Background and objectives: Alterations in mitochondrial DNA (mtDNA) have been observed and studied in various diseases. However, the clinical value of the mtDNA copy number (mtDNA-CN) alterations in osteonecrosis of the femoral head (ONFH) is poorly understood. In the present study, we investigated whether alterations in mtDNA-CNs are associated with clinicopathological parameters in ONFH. Materials and methods: MtDNA-CNs in the synovial tissue of 34 patients with ONFH and 123 control tissues (femoral neck fracture) were measured using quantitative real-time PCR. The present study then analyzed the correlation between the mtDNA-CN and the clinicopathological characteristics of ONFH and fracture patients. Results: The average mtDNA-CN (mean ± standard deviation) was 23.82 ± 22.37 and 25.04 ± 24.27 in ONFH and control tissues, respectively, and was not significantly different between the groups (p = 0.792). The mtDNA-CN was positively associated with age (27.7% vs. 45.9%, p = 0.018) and negatively associated with the erythrocyte sedimentation rate (ESR) (11.8% vs. 39.7%, p = 0.024) in all of the samples. The study also found further associations with age (22.2% vs. 68.8%, p = 0.014), gender (30.0% vs. 64.3%, p = 0.048), and ESR (0% vs. 57.7%, p = 0.043) in ONFH. Conclusions: in this study, we demonstrated that mtDNA-CN might be a significant marker for predicting clinical characteristics in ONFH.

Rapid development of dual porous poly(lactic acid) foam using fused deposition modeling (FDM) 3D printing for medical scaffold application.

The poor melt property and brittleness of poly(lactic acid) (PLA) cause difficulties in extrusion foaming and decrease product performance in industrial and research fields. In this paper, the rheological properties of PLA resin were improved using an epoxy chain extension reaction, which led to the improvement of pore properties such as morphology and foamability. Reinforced PLA was extruded in a porous filament, and a scaffold was fabricated with design freedom, one-step processing, and dual porosity by extrusion foaming and 3D printing. In addition, in vitro cell culture tests were performed to verify the cell biology assessment and confirm the potential of the scaffold for application as medical scaffolds.

Laser-Processed Nature-Inspired Deformable Structures for Breathable and Reusable Electrophysiological Sensors toward Controllable Home Electronic Appliances and Psychophysiological Stress Monitoring.

Physiological monitoring through skin patch stretchable devices has received extensive attention because of their significant findings in many human-machine interaction applications. In this paper, we present novel nature-inspired, kiri-spider, serpentine structural designs to sustain mechanical deformations under complex stress environments. Strain-free mechanical structures involving stable high areal coverage (spiderweb), three-dimensional out-of-plane deformations (kirigami), and two-dimensional (2D) stretchable (2D spring) electrodes demonstrated high levels of mechanical loading under various strains, which were verified through theoretical and experimental studies. Alternative to conventional microfabrication procedures, sensors fabricated by a facile and rapid benchtop programmable laser machine enabled the realization of low-cost, high-throughput manufacture, followed by transferring procedures with a nearly 100% yield. For the first time, we demonstrated laser-processed thin (∼10 µm) flexible filamentary patterns embedded within the solution-processed polyimide to make it compatible with current flexible printed circuit board electronics. A patch-based sensor with thin, breathable, and sticky nature exhibited remarkable water permeability >20 g h-1 m-2 at a thickness of 250 µm. Moreover, the reusability of the sensor patch demonstrated the significance of our patch-based electrophysiological sensor. Furthermore, this wearable sensor was successfully implemented to control human-machine interfaces to operate home electronic appliances and monitor mental stress in a pilot study. These advances in novel mechanical architectures with good sensing performances provide new opportunities in wearable smart sensors.

Color-sensitive and spectrometer-free plasmonic sensor for biosensing applications.

A color-sensitive and spectrometer-free sensing method using plasmonic nanohole arrays and the color components, L* , a* , and b* , of the CIELAB defined by the international commission on illumination (CIE) is introduced for the analysis of optically transparent materials in the visible range. Spectral analysis based on plasmonic nanoparticles or nanostructures can be applied to real-time bio-detection, but complex optical instrumentations and low spatial resolution have limited the sensing ability. Therefore, we take an advantage of color image processing instead of spectral analysis which induces the distinctive color information of plasmonic nanohole arrays with different transparent materials. It guarantees high spatial resolution which is essential to bio-detection such as living cells. To establish our sensing platform, the color components, L* , a* , and b* , were extracted from photo images by an image sensor, statistically processed using a JAVA program, and finally utilized as three individual sensing factors. Additionally, our study on a correlation between the spacing of plasmonic sensors and the color sensitivity to the refractive index reveals geometrically optimal conditions of nanohole arrays. The weighted mean calculation with the three individual sensing factors offers an enhanced distinction of the optical difference for transparent materials. In this work, a color sensitivity of 156.94 RIU-1 and a minimum mean absolute error of 1.298×10-4 RIU were achieved. The difference in the refractive index can be recognized up to 10-4 level with the suggested sensing platform and the signal process. This unique color-sensitive sensing method enables a simple, easy-to-control, and highly accurate analysis without complicated measurement systems including a spectrometer. Therefore, our sensing platform can be applied as a very powerful tool to in-situ label-free bio-detection fields.

Single Pass Laser Process for Super-Hydrophobic Flexible Surfaces with Micro/Nano Hierarchical Structures.

Wetting has been studied in various fields: chemical industry, automobile manufacturing, food companies, and even life sciences. In these studies, super-hydrophobic surfaces have been achieved through complex steps and processes. To realize super-hydrophobicity, however, we demonstrated a simple and single pass laser process for the fabrication of micro/nano hierarchical structures on the flexible polytetrafluoroethylene (PTFE, Teflon) surface. The fabricated hierarchical structures helped increase the hydrophobicity by augmenting the surface roughness and promoting air-trapping. In addition, we employed a low-cost and high-throughput replication process producing numerous polydimethylsiloxane (PDMS) replicas from the laser-processed PTFE film. Thanks to the anti-adhesive characteristics of PTFE and the elasticity of PDMS, the structure perfectly transferred to the replica without any mechanical failure. Moreover, our designed mesh patterns offered the possibility of large area applications through varying the process parameters (pitch, beam spot size, laser fluence, and scan speed). Even though mesh patterns had relatively large pitch (190 µm), we were able to achieve high contact angle (>150°). Through pneumatically deformed structure, we clearly showed that the shape of the droplets on our laser-processed super-hydrophobic surface was spherical. Based on these outcomes, we can expect our single laser pulse exposure process can overcome many drawbacks and offer opportunities for advancing applications of the wetting phenomena.

Laser direct writing and inkjet printing for a sub-2 µm channel length MoS2 transistor with high-resolution electrodes.

Patterns formed by the laser direct writing (LDW) lithography process are used either as channels or barriers for MoS2 transistors fabricated via inkjet printing. Silver (Ag) nanoparticle ink is printed over patterns formed on top of the MoS2 flakes in order to construct high-resolution source/drain (S/D) electrodes. When positive photoresist is used, the produced grooves are filled with inkjetted Ag ink by capillary forces. On the other hand, in the case of negative photoresist, convex barrier-like patterns are written on the MoS2 flakes and patterns, dividing the printed Ag ink into the S/D electrodes by self-alignment. LDW lithography combined with inkjet printing is applied to MoS2 thin-film transistors that exhibit moderate electrical performance such as mobility and subthreshold swing. However, especially in the linear operation regime, their features are limited by the contact effect. The Y-function method can exclude the contact effect and allow proper evaluation of the maximum available mobility and contact resistance. The presented fabrication methods may facilitate the development of cost-effective fabrication processes.

Laser Direct Writing Process for Making Electrodes and High-k Sol-Gel ZrO2 for Boosting Performances of MoS2 Transistors.

A series of two-dimensional (2D) transition metal dichalcogenides (TMDCs), including molybdenum disulfide (MoS2), can be attractive materials for photonic and electronic applications due to their exceptional properties. Among these unique properties, high mobility of 2D TMDCs enables realization of high-performance nanoelectronics based on a thin film transistor (TFT) platform. In this contribution, we report highly enhanced field effect mobility (µ(eff) = 50.1 cm(2)/(V s), ∼2.5 times) of MoS2 TFTs through the sol-gel processed high-k ZrO2 (∼22.0) insulator, compared to those of typical MoS2/SiO2/Si structures (µ(eff) = 19.4 cm(2)/(V s)) because a high-k dielectric layer can suppress Coulomb electron scattering and reduce interface trap concentration. Additionally, in order to avoid costly conventional mask based photolithography and define the patterns, we employ a simple laser direct writing (LDW) process. This process allows precise and flexible control with reasonable resolution (up to ∼10 nm), depending on the system, and enables fabrication of arbitrarily patterned devices. Taking advantage of continuing developments in laser technology offers a substantial cost decrease, and LDW may emerge as a promising technology.

Facile fabrication of a superhydrophobic cage by laser direct writing for site-specific colloidal self-assembled photonic crystal.

Micron-sized ablated surface structures with nano-sized 'bumpy' structures were produced by femtosecond (fs) laser ablation of polytetrafluoroethylene (PTFE) film under ambient conditions. Upon just a single step, the processed surface exhibited hierarchical micro/nano morphology. In addition, due to the tribological properties of PTFE, polydimethylsiloxane (PDMS) could be replicated from the laser-ablated PTFE surface without anti-adhesive surface treatment. By controlling the design of the ablated patterns, tunable wettability and superhydrophobicity were achieved on both PTFE and PDMS replica surfaces. Furthermore, using fs laser ablation direct writing, a flexible superhydrophobic PDMS cage formed by superhydrophobic patterns encompassing the unmodified region was demonstrated for aqueous droplet positioning and trapping. Through evaporation-driven colloidal self-assembly in this superhydrophobic cage, a colloidal droplet containing polystyrene (PS) particles dried into a self-assembled photonic crystal, whose optical band gap could be manipulated by the particle size.

High-performance inkjet-printed four-terminal microelectromechanical relays and inverters.

We report the first demonstration of inkjet-printed 4-terminal microelectromechanical (MEM) relays and inverters with hyper-abrupt switching that exhibit excellent electrical and mechanical characteristics. This first implementation of a printed 4-terminal device is critically important, since it allows for the realization of full complementary logic functions. The floated fourth terminal (body electrode), which allows the gate switching voltage to be adjusted, is bonded to movable channel beams via a printed epoxy layer in a planar structure, which can move downward together via the electrostatic force between the gate electrodes and body such that the channel can also actuate downward and touch the drain electrode. Because the body, channel, and drain electrodes are completely electrically separated, no detectable leakage or electrical interference between the electrodes is observed. The printed MEM relay exhibited an on-state resistance of only 3.48 Ω, immeasurable off-state leakage, subthreshold swing <1 mV/dec, and a stable operation over 10(4) cycles with a switching delay of 47 µs, and the relay inverter exhibits abrupt transitions between on/off states. The operation of the printed 4-terminal MEM relay was also verified against the results of a 3-dimensional (3D) finite element simulation.