Ultra-Thin GaAs Single-Junction Solar Cells for Self-Powered Skin-Compatible Electrocardiogram Sensors

GaAs thin-film solar cells have high efficiency, reliability, and operational stability, making them a promising solution for self-powered skin-conformal biosensors. However, inherent device thickness limits suitability for such applications, making them uncomfortable and unreliable in flexural environments. Therefore, reducing the flexural rigidity becomes crucial for integration with skin-compatible electronic devices. Herein, this study demonstrated a novel one-step surface modification bonding methodology, allowing a streamlined transfer process of ultra-thin (2.3 µm thick) GaAs solar cells on flexible polymer substrates. This reproducible technique enables strong bonding between dissimilar materials (GaAs-polydimethylsiloxane, PDMS) without high external pressures and temperatures. The fabricated solar cell showed exceptional performance with an open-circuit voltage of 1.018 V, short-circuit current density of 20.641 mA cm-2, fill factor of 79.83%, and power conversion efficiency of 16.77%. To prove the concept, the solar cell is integrated with a skin-compatible organic electrochemical transistor (OECT). Competitive electrical outputs of GaAs solar cells enabled high current levels of OECT under subtle light intensities lower than 50 mW cm-2, which demonstrates a self-powered electrocardiogram sensor with low noise (signal-to-noise ratio of 32.68 dB). Overall, this study presents a promising solution for the development of free-form and comfortable device structures that can continuously power wearable devices and biosensors.

A surface treatment method for improving the attachment of PDMS: acoustofluidics as a case study

A method for a permanent surface modification of polydimethylsiloxane (PDMS) is presented. A case study on the attachment of PDMS and the lithium niobate (LiNbO3) wafer for acoustofluidics applications is presented as well. The method includes a protocol for chemically treating the surface of PDMS to strengthen its bond with the LiNbO3 surface. The PDMS surface is modified using the 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) silane reagent. The effect of silane treatment on the hydrophilicity, morphology, adhesion strength to LiNbO3, and surface energy of PDMS is investigated. The results demonstrated that the silane treatment permanently increases the hydrophilicity of PDMS and significantly alters its morphology. The bonding strength between PDMS and LiNbO3increased with the duration of the silane treatment, reaching a maximum of approximately 500 kPa. To illustrate the effectiveness of this method, an acoustofluidic device was tested, and the device demonstrated very promising enhanced bonding and sealing capabilities with particle manipulation at a flow rate of up to 1 L/h by means of traveling surface acoustic waves (TSAW). The device was reused multiple times with no fluid leakage or detachment issues. The utility of the presented PDMS surface modification method is not limited to acoustofluidics applications; it has the potential to be further investigated for applications in various scientific fields in the future.

Engineered kirigami design of PVDF-Pt core-shell nanofiber network for flexible transparent electrode

Nanofiber networks comprising polymer-metal core-shell structures exhibit several advantages, such as high uniformities and considerable flexibilities. Additionally, the flexibility of the nanofiber network may be further enhanced by engineering the network topology. Therefore, in this study, the topologies of polyvinylidene fluoride (PVDF)-Pt core-shell nanofiber (CS NF) networks were engineered, and their performances as flexible transparent electrodes were comprehensively evaluated. Three distinct topologies of nanofiber networks were induced using circular, square, and rectangular electrode collectors. A highly uniform nanofiber network was obtained using the square electrode collector, which generated a high density of nanofiber junctions (nodes). Consequently, this nanofiber network exhibited the smallest sheet resistance [Formula: see text] and lowest optical transmittance [Formula: see text] among the three CS NF networks. In contrast, nanofiber bundles were frequently formed in the randomly aligned CS NF network prepared using the circular electrode collector, reducing the node density. As a result, it simultaneously exhibited a very small [Formula: see text] and high [Formula: see text], generating the largest percolation figure of merit [Formula: see text]. Under certain strain directions, the CS NF network with the engineered topology exhibited a significantly enhanced mechanical durability. Finally, a flexible piezoelectric pressure sensor with CS NF network electrodes was fabricated and its sensing performance was excellent.

Highly efficient thin-film 930 nm VCSEL on PDMS for biomedical applications

Recently, biocompatible optical sources have been surfacing for new-rising biomedical applications, allowing them to be used for multi-purpose technologies such as biological sensing, optogenetic modulation, and phototherapy. Especially, vertical-cavity surface-emitting laser (VCSEL) is in the spotlight as a prospective candidate for optical sources owing to its low-driving current performance, low-cost, and package easiness in accordance with two-dimensional (2D) arrays structure. In this study, we successfully demonstrated the actualization of biocompatible thin-film 930 nm VCSELs transferred onto a Polydimethylsiloxane (PDMS) carrier. The PDMS feature with biocompatibility as well as biostability makes the thin-film VCSELs well-suited for biomedical applications. In order to integrate the conventional VCSEL onto the PDMS carrier, we utilized a double-transfer technique that transferred the thin-film VCSELs onto foreign substrates twice, enabling it to maintain the p-on-n polarity of the conventional VCSEL. Additionally, we employed a surface modification-assisted bonding (SMB) using an oxygen plasma in conjunction with silane treatment when bonding the PDMS carrier with the substrate-removed conventional VCSELs. The threshold current and maximum output power of the fabricated 930 nm thin-film VCSELs are 1.08 mA and 7.52 mW at an injection current of 13.9 mA, respectively.

Pyroelectrically Charged Flexible Ferroelectret-Based Tactile Sensor for Surface Texture Detection

Texture detection is one of the essential features requested for artificial tactile sensing to push the demand for flexible low-cost tactile sensors in the robotics sector. In this manuscript, we demonstrate the ability of a ferroelectret-based pressure sensor together with a patterned elastomer layer to detect surface textures. The ferroelectret sensor was fabricated using fluorinated ethylene propylene (FEP) sheets bonded with a patterned adhesive layer to create cavities, integrated with the elastomer bumped surface, and finally charged using a pyroelectric method developed by our group. The ferroelectret-based sensor showed a linear response to the applied force in the range of 0.5 to 2 N, a piezoelectric coefficient of 150.1 ± 3.2 pC/N in the range of 10–80 Hz, and a flat dynamic response in the range of 10–1000 Hz. The tactile sensing characterization of the sensor, performed at different scanning speeds (10 to 30 mm/s) and gratings with different periodicities (0 to 0.8 mm), showed that the fundamental frequencies observed ranged from 12 Hz to 75 Hz, as expected from the model. These results lay the foundation for the adoption of such sensors in different applications that need fine tactile information, such as an autonomous or teleoperated robotic hand, prostheses, and wearable devices.

Improvement in Strain Sensor Stability by Adapting the Metal Contact Layer

Research on stretchable strain sensors is actively conducted due to increasing interest in wearable devices. However, typical studies have focused on improving the elasticity of the electrode. Therefore, methods of directly connecting wire or attaching conductive tape to materials to detect deformation have been used to evaluate the performance of strain sensors. Polyaniline (PANI), a p-type semiconductive polymer, has been widely used for stretchable electrodes. However, conventional procedures have limitations in determining an appropriate metal for ohmic contact with PANI. Materials that are generally used for connection with PANI form an undesirable metal-semiconductor junction and have significant contact resistance. Hence, they degrade sensor performance. This study secured ohmic contact by adapting Au thin film as the metal contact layer (the MCL), with lower contact resistance and a larger work function than PANI. Additionally, we presented a buffer layer using hard polydimethylsiloxane (PDMS) and structured it into a dumbbell shape to protect the metal from deformation. As a result, we enhanced steadiness and repeatability up to 50% strain by comparing the gauge factors and the relative resistance changes. Consequently, adapting structural methods (the MCL and the dumbbell shape) to a device can result in strain sensors with promising stability, as well as high stretchability.

A Novel Computer-Controlled Maskless Fabrication Process for Pneumatic Soft Actuators

Template-based and additive manufacturing techniques have demonstrated some fabrication routes for creating pneumatic soft actuators. However, as the complexity and capability of the actuators continue to develop, the limitations of these approaches are becoming evident. These include difficulties for design variations, process speed and resolution, material compatibility and scalability, which hinder and restrict both the possible capabilities of the technology and its transition from research to industry. This body of work presents a computer-controlled, maskless manufacturing process with a different approach to allow for high-speed, low-cost and flexible creation of pneumatic soft actuation networks comprising multi-material construction. This was investigated through a bespoke fabrication platform that provides computer-controlled localised plasma treatment to selectively modify the chemical behaviour on the surface of silicone and polyethylene terephthalate (PET) bodies. The altered surface chemistry facilitated selective bond formation between the treated parts of the surface and, consequently, greater design variation and control over the pneumatic chambers that were formed. Selective treatment patterns allowed nonlinear pneumatic chamber designs to be created, and the strength of bonded silicone structures was shown to facilitate large deformations in the actuators. Furthermore, the different interactions between the plasma and silicone were leveraged to achieve feature sizes of <1 mm and treatment speeds of 20 mm2 per second of exposure. Two multi-material pneumatic soft actuators were then fabricated to demonstrate the potential of the platform as an automated manufacturing route for soft actuators.

High-Throughput Tailoring of Nanocellulose Films: From Complex Bio-Based Materials to Defined Multifunctional Architectures

This paper demonstrates a high-throughput approach to fabricate nanocellulose films with multifunctional performance using conventionally existing unit operations. The approach comprises cast-coating and direct interfacial atmospheric plasma-assisted gas-phase modification along with the microscale patterning technique (nanoimprint lithography, NIL), all applied in roll-to-roll mode, to introduce organic functionalities in conjunction with structural manipulation. Our strategy results in multifunctional cellulose nanofibrils (CNF) films in which the high optical transmittance (∼90%) is retained while the haze can be adjusted (2-35%). Concomitantly, the hydrophobic/hydrophilic balance can be tuned (50-21 mJ/m² with the water contact angle ranging from ∼20 up to ∼120°), while intrinsic hygroscopicity of CNF films is not significantly compromised. Therefore, a challenge to produce multifunctional bio-based materials with properties defined by various high-performance applications conjoined to the lack of efficient processing strategies is elucidated. Overall, economically and ecologically viable strategy, which was realized by facile and upscalable unit operations using the R2R technology, is introduced to expand the properties' spaces and thus offer a vast variety of interesting applications for CNF films.

Adaptive architecture and mechanoresponse of epithelial cells on a torus

Curvature is a geometric feature widely observed in the epithelia and critical to the performance of fundamental biological functions. Understanding curvature-related biophysical phenomena remains challenging partly owing to the difficulty of quantitatively tuning and measuring curvatures of interfacing individual cells. In this study, we prepared confluent wild-type Madin-Darby canine kidney cells on a torus structure presenting positive, zero, and negative Gaussian curvatures with a tubule diameter of 2-7 cells and quantified the mechanobiological characteristics of individual cells. Cells on the torus surface exhibited topological sensing ability both as an individual cell and collective cell organization. Both cell bodies and nuclei, adapted on the torus, exhibited local Gaussian curvature-dependent preferential orientation. The cells on the torus demonstrated significant adjustment in the nuclear area and exhibited asymmetric nuclear position depending on the local Gaussian curvature. Moreover, cells on top of the torus, where local Gaussian curvature is near zero, exhibited more sensitive morphological adaptations than the nuclei depending on the Gaussian curvature gradient. Furthermore, the spatial heterogeneity of intermediate filament proteins related to mechanoresponsive expression of the cell body and nucleus, vimentin, keratin and lamin A, revealed local Gaussian curvature as a key factor of cellular adaptation on curved surfaces.

Multimode Hydraulically Amplified Electrostatic Actuators for Wearable Haptics

The sense of touch is underused in today's virtual reality systems due to lack of wearable, soft, mm-scale transducers to generate dynamic mechanical stimulus on the skin. Extremely thin actuators combining both high force and large displacement are a long-standing challenge in soft actuators. Sub-mm thick flexible hydraulically amplified electrostatic actuators are reported here, capable of both out-of-plane and in-plane motion, providing normal and shear forces to the user's fingertip, hand, or arm. Each actuator consists of a fluid-filled cavity whose shell is made of a metalized polyester boundary and a central elastomer region. When a voltage is applied to the annular electrodes, the fluid is rapidly forced into the stretchable region, forming a raised bump. A 6 mm × 6 mm × 0.8 mm actuator weighs 90 mg, and generates forces of over 300 mN, out-of-plane displacements of 500 µm (over 60% strain), and lateral motion of 760 µm. Response time is below 5 ms, for a specific power of 100 W kg^-1 . In user tests, human subjects distinguished normal and different 2-axis shear forces with over 80% accuracy. A flexible 5 × 5 array is demonstrated, integrated in a haptic sleeve.

Heat and pressure-resistant room temperature irreversible sealing of hybrid PDMS–thermoplastic microfluidic devices via carbon–nitrogen covalent bonding and its application in a continuous-flow polymerase chain reaction

In this study, we have introduced a facile room-temperature strategy for irreversibly sealing polydimethylsiloxane to various thermoplastics using (3-aminopropyl)triethoxysilane (APTES) and [2-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ECTMS).

Microfluidic device fabrication mediated by surface chemical bonding

This review discusses on various bonding techniques for fabricating microdevices with a special emphasis on the modification of surface assisted by the use of chemicals to assemble microfluidic devices at room temperature under atmospheric pressure.

Contact-active antibacterial polyethylene foils via atmospheric air plasma induced polymerisation of quaternary ammonium salts

Polyethylene (PE) foils were modified with potent contact-active antibacterial quaternary ammonium salts (QAS) by an atmospheric air plasma activation step, followed by graft-polymerisation of vinylbenzyltrimethylammonium chloride (VBTAC) monomers. The presented approach uses a cost efficient air plasma activation and subsequent radical polymerisation in highly concentrated aqueous monomer solutions to generate efficient antibacterial materials. The obtained contact-active poly-VBTAC modified PE foils feature a homogeneous and 300 nm thick polymer layer with a high charge density of approximately 10¹⁶ N⁺/cm². The antibacterial properties were evaluated against Gram-negative (P. aeruginosa, E. coli) and Gram-positive (S. aureus, S. epidermidis) bacteria. The materials showed strong antibacterial activity by eradicating all the inoculated bacteria with bacterial challenges of 10⁴ to 10⁵ CFU/cm² and good reductions even at maximum challenge (10⁸ CFU/cm²). We have confirmed contact-activity by an agar diffusion assay. The obtained materials are therefore highly attractive for applications, for example, in packaging and are a contribution to an ecomic and green antimicrobial management without release of biocides to the environment.

Adhesive-free adhesion between heat-assisted plasma-treated fluoropolymers (PTFE, PFA) and plasma-jet-treated polydimethylsiloxane (PDMS) and its application

Conventional low-temperature plasma treatment was reported to minimally improve the adhesion property of polytetrafluoroethylene (PTFE), whereas heat-assisted plasma (HAP) treatment significantly improved the same. An unvulcanized rubber was previously used as an adherent for PTFE. This study aimed to achieve strong adhesive-free adhesion between PTFE and vulcanized polydimethylsiloxane (PDMS) rubber. As-received vulcanized PDMS rubber did not adhere to HAP-treated PTFE, and as-received PTFE did not adhere to vulcanized rubber of plasma-jet (PJ) treated PDMS rubber; however, HAP-treated PTFE strongly adhered to vulcanized PJ-treated PDMS rubber, and both PTFE and PDMS exhibited cohesion failure in the T-peel test. The surface chemical compositions of the PTFE and PDMS sides were determined using X-ray photoelectron spectroscopy. The strong PTFE/PDMS adhesion was explained via hydrogen and covalent bond formation (C–O–Si and/or C(=O)–O–Si) between hydroxyl (C–OH) or carboxyl (C(=O)–OH) groups of the HAP-treated PTFE. This process was also applied to adhesive-free adhesion between a tetrafluoroethylene–perfluoroalkylvinylether copolymer (PFA) and PDMS; subsequently, a translucent PFA/PDMS assembly with strong adhesion was realized together with the PTFE/PDMS assembly. Strong adhesive-free adhesion between fluoropolymers (PTFE, PFA) and vulcanized PDMS rubber without using any adhesives and graft polymer was successfully realized upon plasma treatment of both the fluoropolymer and PDMS sides. Additionally, a PDMS sheet, which was PJ-treated on both sides, was applied to strongly adhere fluoropolymers (PTFE, PFA) to materials such as metal and glass. PJ-treated PDMS was used as an intermediate layer rather than a strong adhesive, achieving PTFE/PDMS/metal and PTFE/PDMS/glass assemblies. The PTFE/PDMS, PDMS/metal, and PDMS/glass adhesion strengths exceeded 2 N/mm.

Covalent Bonding of Thermoplastics to Rubbers for Printable, Reel-to-Reel Processing in Soft Robotics and Microfluidics

The lamination of mechanically stiff structures to elastic materials is prevalent in biological systems and popular in many emerging synthetic systems, such as soft robotics, microfluidics, stretchable electronics, and pop-up assemblies. The disparate mechanical and chemical properties of these materials have made it challenging to develop universal synthetic procedures capable of reliably adhering to these classes of materials together. Herein, a simple and scalable procedure is described that is capable of covalently laminating a variety of commodity ("off-the-shelf") thermoplastic sheets to silicone rubber films. When combined with laser printing, the nonbonding sites can be "printed" onto the thermoplastic sheets, enabling the direct fabrication of microfluidic systems for actuation and liquid handling applications. The versatility of this approach in generating thin, multifunctional laminates is demonstrated through the fabrication of milliscale soft actuators and grippers with hinged articulation and microfluidic channels with built-in optical filtering and pressure-dependent geometries. This method of fabrication offers several advantages, including technical simplicity, process scalability, design versatility, and material diversity. The concepts and strategies presented herein are broadly applicable to the soft robotics, microfluidics, and advanced and additive manufacturing communities where hybrid rubber/plastic structures are prevalent.

Integration of Heterogeneous Materials for Wearable Sensors

Wearable sensors are of interest for several application areas, most importantly for their potential to allow for the design of personal continuous health monitoring systems. For wearable sensors, flexibility is required and imperceptibility is desired. Wearable sensors must be robust to strain, motion, and environmental exposure. A number of different strategies have been utilized to achieve flexibility, imperceptibility, and robustness. All of these approaches require the integration of materials having a range of chemical, mechanical, and thermal properties. We have given a concise review of the range of materials that must be incorporated in wearable sensors regardless of the strategies adopted to achieve wearability. We first describe recent advances in the range of wearable sensing materials and their processing requirements and then discuss the potential routes to the integration of these heterogeneous materials.

Understanding the mechanisms of oxygen diffusion through surface functionalized nanocellulose films

A concept for direct surface modification on self-standing films of cellulose nanofibrils (CNF) is demonstrated using an aminosilane group in cellulose compatible solvent (dimethyl acetamide, DMA). The chemically modified structure efficiently prevents the oxygen molecules from interacting with the nanocellulose film in the presence of water molecules. Oxygen permeability values lower than 1mLmmm^-2day^-1atm^-1 were achieved at extremely high levels of relative humidity (RH95%). The aminosilane reaction is compared to conventional hydrophobization reaction using hexamethyldisilazane. The differences with respect to interactions between cellulosic nanofibrils, water and oxygen molecules taking place with aminated and silylated CNF films correlated with the degree of surface substitution, surface hydrophilicity and permeability of the formed layer. The self-condensation reactions taking place on the film surface during aminosilane-mediated bonding were decisive for low oxygen permeability. Experimental evidence on the importance of interfacial processes that hinder the water-cellulose interactions while keeping film's low affinity towards oxygen is demonstrated.

Flow-Through Electroporation of HL-60 White Blood Cell Suspensions using Nanoporous Membrane Electrodes

A flow-through electroporation system, based on a novel nanoporous membrane/electrode design, for the delivery of cell wall-impermeant molecules into model leukocytes, HL-60 promyelocytes, was demonstrated. The ability to apply low voltages to cell populations, with nm-scale concentrated electric field in a periodic array, contributes to high cell viability. With applied biases of 1-4V, delivery of target molecules was achieved with 90% viability and up to 65% transfection efficiency. More importantly, the system allowed electrophoretic pumping of molecules from a microscale reservoir across the membrane/electrode system into a microfluidic flow channel for transfection of cells, a design that can reduce reagent amount by eightfold compared to current strategies. The flow-through system, which forces intimate membrane/electrode contact by using a 10μm channel height, can be easily scaled-up by adjusting the microfluidic channel geometry and/or the applied voltage pulse frequency to control cell residence times at the cell membrane/electrode interface. The demonstrated system shows promise in clinical applications where low-cost, high cell viability and high volume transfection methods are needed without the risk of viral vectors. In particular genetic modification of freely mobile white blood cells to either target disease cells or to express desired protein/enzyme biomolecules is an important target platform enabled by this device system.

Self-regenerating and hybrid irreversible/reversible PDMS microfluidic devices

This paper outlines a straightforward, fast, and low-cost method to fabricate polydimethylsiloxane (PDMS) chips. Termed sandwich bonding (SWB), this method requires only a laboratory oven. Initially, SWB relies on the reversible bonding of a coverslip over PDMS channels. The coverslip is smaller than the substrate, leaving a border around the substrate exposed. Subsequently, a liquid composed of PDMS monomers and a curing agent is poured onto the structure. Finally, the cover is cured. We focused on PDMS/glass chips because of their key advantages in microfluidics. Despite its simplicity, this method created high-performance microfluidic channels. Such structures featured self-regeneration after leakages and hybrid irreversible/reversible behavior. The reversible nature was achieved by removing the cover of PDMS with acetone. Thus, the PDMS substrate and glass coverslip could be detached for reuse. These abilities are essential in the stages of research and development. Additionally, SWB avoids the use of surface oxidation, half-cured PDMS as an adhesive, and surface chemical modification. As a consequence, SWB allows surface modifications before the bonding, a long time for alignment, the enclosure of sub-micron channels, and the prototyping of hybrid devices. Here, the technique was successfully applied to bond PDMS to Au and Al.

Polysiloxane layers created by sol-gel and photochemistry: ideal surfaces for rapid, low-cost and high-strength bonding of epoxy components to polydimethylsiloxane

In this article we introduce and compare three techniques for low-cost and rapid bonding of stereolithographically structured epoxy components to polydimethylsiloxane (PDMS). In short, we first create a polysiloxane layer on the epoxy surface via silane surface coupling and polymerization. Afterwards, the modified epoxy surface can be bonded to a PDMS component at room temperature using a handheld corona discharger, which is a commonly used low-cost technique for bonding two PDMS components. Using these methods bonds of desirable strength can be generated within half an hour. Depending on the epoxy resin, we found it necessary to modify the silanization procedure. Therefore, we provide a total of three different silanization techniques that allow bonding of a wide variety of stereolithographically structurable epoxy resins. The first technique is a UV-light induced silanization process which couples a silane that contains an epoxy-ring ((3-glycidoxypropyl)trimethoxysilane (GPTMS)). For surfaces that cannot be modified with this silane we use dimethoxydimethylsilane (DMDMS). This silane can either be coupled to the surface by a sol-gel process or UV-light induced polymerisation. The sol-gel process which is a heat induced surface modification technique results in high bond strengths. Because of the heat which triggers the sol-gel process, this technique is limited to epoxy polymers with high glass transition temperatures. For the majority of stereolithographically structured epoxy resins which typically have glass transition temperatures of around 60 °C the light-induced bonding technique is preferable. For all three techniques we performed DIN EN-conform tensile testing demonstrating maximum bond strengths of up to 350 kPa which is comparable with bond strengths reported for PDMS-to-PDMS bonds. For all bond methods, long-term stability as well as hydrolytic stability was assessed.

Wafer-scale fabrication of glass-FEP-glass microfluidic devices for lipid bilayer experiments

We report a wafer-scale fabrication process for the production of glass-FEP-glass microdevices using UV-curable adhesive (NOA81) as gluing material, which is applied using a novel "spin & roll" approach. Devices are characterized for the uniformity of the gluing layer, presence of glue in the microchannels, and alignment precision. Experiments on lipid bilayers with electrophysiological recordings using a model pore-forming polypeptide are demonstrated.

Fabrication of two dimensional polyethylene terephthalate nanofluidic chip using hot embossing and thermal bonding technique

We present in this paper a method for obtaining a low cost and high replication precision 2D (two dimensional) nanofluidic chip with a PET (polyethylene terephthalate) sheet, which uses hot embossing and a thermal bonding technique. The hot embossing process parameters were optimized by both experiments and the finite element method to improve the replication precision of the 2D nanochannels. With the optimized process parameters, 174.67 ± 4.51 nm wide and 179.00 ± 4.00 nm deep nanochannels were successfully replicated into the PET sheet with high replication precision of 98.4%. O2 plasma treatment was carried out before the bonding process to decrease the dimension loss and improve the bonding strength of the 2D nanofluidic chip. The bonding parameters were optimized by bonding rate of the nanofluidic chip. The experiment results show that the bonding strength of the 2D PET nanofluidic chip is 0.664 MPa, and the total dimension loss of 2D nanochannels is 4.34 ± 7.03 nm and 18.33 ± 9.52 nm, in width and depth, respectively. The fluorescence images demonstrate that there is no blocking or leakage over the entire micro- and nanochannels. With this fabrication technology, low cost polymer nanochannels can be fabricated, which allows for commercial manufacturing of nano-components.

LDI-MS examination of oxygen plasma modified polymer for designing tailored implant biointerfaces

A versatile parylene C coating for biomaterials was fabricated by the mild oxygen plasma treatment and examined by the use of LDI-MS..