Papers by Keyword: Microfluidic Chip

Abstract: In the past few years, micro-droplets have been widely used in diverse fields of biological and chemical research, spanning from drug delivery and material synthesis to point-of-care diagnostics, digital PCR, and single-cell analysis. Droplet-based microfluidics offers a powerful platform for conducting complex experiments, screening processes, and analyses with enhanced precision, efficiency, and versatility. While creating droplets with uniform sizes is a common objective of microfluidics, it is not limited to producing droplets of a single size per chip. Creating microdroplets with different sizes on a microfluidic chip holds significant importance in various applications. This can provide flexibility in controlling chemical processes, biological reactions, or product quality. By controlling the size of the microdroplets, researchers can precisely regulate the release kinetics of the encapsulated substances, leading to improved therapeutic outcomes and reduced side effects for patients. In chemical analysis, microfluidic platforms can produce microdroplets of different sizes to enable high-throughput screening of chemical reactions or biological assays. By manipulating the droplet size, researchers can enhance reaction efficiency, increase sample throughput, and reduce reagent consumption, making the analysis process more cost-effective and time-efficient. To create microdroplets with different sizes on a microfluidic chip, adjusting process parameters such as pressure, flow rate, and channel design is an approach. In this research, geometrical parameters of the channel such as shape, size, and length are calculated to ensure the pressure drop from the inlet to the creation point droplets of each branch is the same, ensuring the stable operation of the system. The input solution in the research is glucose, which fully exhibits the behavior of a non-Newtonian liquid under defined conditions. The power law viscosity model is used to describe the rheological behavior of glucose liquids.

Abstract: Microfluidic chip injection photocuring is a new method for microfluidic chip fabrication. The accuracy of microfluidic chip photocuring has an important impact on the reliability of microfluidic chip. The reaction rate of photocuring system directly affects the final quality and efficiency of microfluidic chip. The rapid reaction rate of photocuring system will lead to poor feeding effect of the reaction system. The forming accuracy is affected, and the reaction rate is too slow, which will increase the forming time and affect the forming efficiency. In this paper, the conversion rate and reaction rate of different active monomers and oligomers used in the formulation system of microfluidic chips were measured on-line. The photocuring reaction kinetics of microfluidic chips was studied, and the influence of the formulation system on the photocuring reaction was explored, which laid a foundation for optimizing the formulation of microfluidic chips.

Abstract: High-throughput drug screening microfluidic chip has good biocompatibility and faveriable functional integration, which is the excellent platform for high-throughput screening. Importantly, FRET (Fluorescence Resonance Energy Transfer) technology is the most efficient detection means at present. In this paper, we introduce the development of drug screening microfluidic chip on cellular level and the application of FRET technology on cell detection. Further, we discusse the possibility of FRET applied in the field of microfluidic biochip.

Abstract: Inductance detection methods of metal particle in hydraulic oil are generally based on the inductance change detection. With this method, when particles pass through the microchannel, ferromagnetic and non-ferromagnetic metal particle can be distinguished by monitoring inductance. In this study, it was found that not only inductance pulse but also resistance pulse was produced when detecting particle by inductance detection method. The theory of inductance or resistance change caused by particle is presented from the perspective of electromagnetism in this paper. To verify this phenomenon, the oil sample mixed with different metal particles was forced through the detection coil of microfluidic by constant flow rate. Then several sizes of iron and copper particles were measured. Experimental results showed that the resistance pulses caused by iron particles and copper particles were positive. And for copper particle, SNR (Signal Noise Ratio) of copper particles detected in improved effectively by detecting the resistance pulse.

Abstract: This paper introduce a new polydimethylsiloxan (PDMS) microfluidic chip bonding technology. By studying the influence of prepolymer with different curing agents, curing temperatures and curing time to the PDMS-PDMS chip bonding strength,we get the optimal bonding parameters. The experiment results show that when the cover plate of PDMS with ratio 15:1 bond with the substrate whose ratio is 10:1,the largest strength can be reached. The research which was applied to the packing of microfluidic analysis chip has achieved good results.

Abstract: In this paper, microfluidic chips supply a miniature platform for aptamer biosensor in thrombin detection. The aptamer biosensor was integrated to the microfluidic chip as a recognition element for thrombin detection. Experimental results showed that the aptamer biosensor in microfluidic chip was able to realize the function for human thrombin detection.

Abstract: Microfluidic chips with micro-pillar array to capture cancer cells in a small volume were designed and fabricated in this paper. The structure includes two parts. This chip has a glass slide bonded to a silicon structure, and both of them contain twelve micro-channels with patterned chevrons or U-triangle-bones, micro-pillar array is completed on silicon wafers using wet chemical etching method on the substrate. To monitor cell capture tendency of the structure, the rows of capture structure were modeled using the finite element method (COMSOL Multiphysics). The results show that this structure can decrease the impact force to half or even less, the fluid can go through the micro-pillar array equably and the subjects in the flow can be sizing by the structure.

Abstract: Reducing volumetric warpage during the injection molding process is a challenging problem in the production of microfluidic chips, as the warpage directly affects the bonding quality of the substrate and the cover sheet. In this study, the injection molding of substrate and the cover sheet, composed of PolymethylMethacrylate(PMMA), was simulated. The effect of different process parameters, holding pressure, holding time, mould temperature and injection speed, were investigated via single factor experiments, observing the warpage of the sheet with Three-Coordinate Measuring Machine. The analysis showed that the warpage was affected by non-uniform shrinkage and residual stress of the melt. Holding pressure and holding time had a greater effect on the warpage than the mould temperature and injection speed did. Therefore, reasonable holding pressure and holding time can effectively reduce the warpage of microfluidic chips in the injection molding process.

Abstract: We discuss the effect of joule heat which comes from eletroosmosis flow on the microfluidic chip. Our microfluidic chips are fabricated from polymethyl methacrylate (PMMA). As everyone knows, PMMA is a poor conductor of heat, and its transfer coefficient is only 0.19W/m·K in room temperature. So, the heat is generated by eletroosmosis canʼt conduct outside the microchannels of microfluidic chip easily. We research the effect joule heat on walls of microchannels which are made of PMMA. During our study, interior surface of microchannelsʼ hydrophobicity is changed by effect of joule heat.

Abstract: We research removable electrodes based on microfluidic chip in this paper. The electrodes can be assembled and fixed quickly and easily. We could change toxic electrodes conveniently during experiment. In addition the design of removable electrodes fits different size of channels, because the detection electrodes could be set its position close to outlet of microchannel under the microscope. We provide numerical simulations of COMSOL and hotomicrographs to proving our design in this article.