Process development of the device using in-house plate-to-plate tool with nanoimprint lithography technique for biochip application

Biochip is a promising device with capabilities of performing sorting, trapping and screening a large number of biological samples in a short time. Fabrication of biochip pattern process leads to an opening study towards the development of a working biochip. The traditional photolithography process have a limitation in achieving high throughput for biochip pattern fabrication. In this research, the fabrication process of biochip pattern was developed and the imprint parameter for biochip pattern using an in-house assembled plate-to-plate tool was investigated. The biochip patterns are prepared from existing projection lithography to create the mold. Using soft lithography technique, the biochip pattern was replicated invertly in the PDMS mold. The PDMS mold and in-house plate-to-plate fulfilled the requirement for UV-NIL to imprint biochip patterns on a flexible substrate. Dimension error difference (DED) is the difference between the original design dimensions to fabricated design dimensions. DED was characterized and investigated for precise pattern transfer. UV exposure of 140 W was able to produce the satisfied imprint pattern in biochip pattern mold fabrication. However, higher UV energy caused overexposure in the resist, resulting wider width and bridging. Besides that, crack regions were found when post bake exposure parameters are not properly optimized. The DED between biochip pattern mold and PDMS mold are less compared to biochip pattern mold fabrication in the photolithography process. Critical dimension in the biochip pattern was maintained in the imprint process. However, the higher imprint force will cause an overflow of the resist on the substrate, resulting unsatisfied pattern structure. The proposed parameters for imprinting biochip patterns using in-house plate-to-plate tool are 80 N range and 20 seconds of UV exposure

The Fabrication of PDMS mould for Microelectrode Array Biochip using NIL

In recent years, low-cost micro and nano fabrication process have gain intention from the manufacturing industry. Biochip is a platform of miniaturized microarrays arranged on a solid substrate that allows various biological tests to achieve immediate results. The development of biochip has established a new platform in biomedical industry. However, to fulfill the demands and availability in the market with affordable cost requires high volume manufacturing techniques for the fabrication of the biochips. In this article we will discuss the fabrication of PDMS mould for replicating microelectrode array of biochip. The fabrication of the microelectrodes utilizes the Nanoimprint lithography (NIL) technique. Finally, the fabrication of PDMS mould has been demonstrated successfully for using Nanoimprint lithography (NIL) technique and achieved 13 % of size difference in overall

Three-dimensional soft material micropatterning via grayscale photolithography for improved hydrophobicity of Polydimethylsiloxane (PDMS)

: In this present work, we aim to improve the hydrophobicity of a polydimethylsiloxane (PDMS) surface. Various heights of 3D PDMS micropillars were fabricated via grayscale photolithog�raphy, and improved wettability was investigated. Two approaches of PDMS replication were demonstrated, both using a single master mold to obtain the micropillar arrays. The different heights of fabricated PDMS micropillars were characterized by scanning electron microscopy (SEM) and a surface profiler. The surface hydrophobicity was characterized by measuring the water contact angles. The fabrication of PDMS micropillar arrays was shown to be effective in modifying the contact angles of pure water droplets with the highest 157.3-degree water contact angle achieved by implementing a single mask grayscale lithography technique

PSpHT a Water Strider-like Robot for Water Inspection: Framework and Control Architecture

This paper presents the framework and control of a proposed water strider-liked robot, named as Portable Striding pH Tester (PSpHT) that is able to measure the water quality. PSpHT is designed with its leg and tip configurations made respectively from the light-steel beam and polypropylene-based material. The design of the leg is calculated and fabricated using Archimedes' principle. In addition, real-time software for use in a remote controlled pH data logger that strides the robot, called PSpHT-VI, is developed using radio frequency (RF) communication. The PSpHT is verified and validated by running two specific tests, which are striding topology test and real-time data Potential Hydrogen (pH) reading test. The tests were conducted in a lake within the campus of the Universiti Malaysia Pahang, Pekan

The fabrication of microelectrode array biochip on PET using plate-to-plate NIL

Polyethylene terephthalate (PET) films are useful for various applications due to the characterization of PET were flexibility, thermal resistance and chemical resistant. PET Films are widely used in both commercial and industrial today since they are highly demand in the market. In this study, microelectrode array biochip was fabricated on flexible PET film using (plate-to-plate) nanoimprint lithography (NIL). The PET films acted as substrate while PDMS as the mould. The Polydimethylsiloxane (PDMS) mould was attached on top of the PET film and additionally clamped between two pieces of glass. A mild force was applied to it for REM (replica moulding). A study was carried out upon the surface profiling of the PDMS mould and PET to monitor the possibility of deformation after applying force upon the samples. The experiment shall present the finding of required force to REM the microelectrode array biochip pattern on the PET film

Implementation of a Single Emulsion Mask for Three-Dimensional (3D) Microstructure Fabrication of Micromixers Using the Grayscale Photolithography Technique

Three-dimensional (3D) microstructures have been exploited in various applications of microfluidic devices. Multilevel structures in micromixers are among the essential structures in microfluidic devices that exploit 3D microstructures for different tasks. The efficiency of the micromixing process is thus crucial, as it affects the overall performance of a microfluidic device. Microstructures are currently fabricated by less effective techniques due to a slow point-to-point and layer-by-layer pattern exposure by using sophisticated and expensive equipment. In this work, a grayscale photolithography technique is proposed with the capability of simultaneous control on lateral and vertical dimensions of microstructures in a single mask implementation. Negative photoresist SU8 is used for mould realisation with structural height ranging from 163.8 to 1108.7 µm at grayscale concentration between 60% to 98%, depending on the UV exposure time. This technique is exploited in passive micromixers fabrication with multilevel structures to study the mixing performance. Based on optical absorbance analysis, it is observed that 3D serpentine structure gives the best mixing performance among other types of micromixers