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Warfarin is a drug associated with blood clotting. As the side effects of this drug are fatal, it is important to adjust its dosage for each individual. In particular, DNA analysis of patients is necessary because the effect of the drug varies greatly depending on the genotype of the individual. Real-time PCR technology is usually used for DNA analysis. This technology requires expensive equipment, large space, and long experimental time. To solve these problems, we used a PCR module based on a CMOS photosensor. There are a heater circuit for thermal control on the its back side, and well-like structure on the surface, enabling location based multiplex PCR. We developed primers and probes to detect warfarin-related SNPs, and integrated with the PCR module. We tested the commercial Real-time PCR systems and our PCR modules. Based on the results, we confirmed that the level of performance of our system was similar to that of the commercial systems.

Loop-mediated isothermal amplification (LAMP) may be used in molecular and point-of-care diagnostics for pathogen detection. The amplification occurs under isothermal conditions using up to six primers. However, non-specific amplification is frequently observed in LAMP. Non-specific amplification has the potential to be triggered by forward and reverse internal primers. And the relatively low reaction temperature (55-65 °C) induces the secondary structure via primer-primer interactions. Primer redesign and probe design have been recommended to solve this problem. LAMP primers have strict conditions, such as Tm, GC contents, primer dimer, and distance between primers compared to conventional PCR primers. Probe design requires specialized knowledge to have high specificity for a target. In polymerase chain reaction (PCR), some chemicals or proteins are used for improving specificity and efficiency. Therefore, we hypothesized that additives can suppress the non-specific amplification. In this study, tetramethylammonium chloride (TMAC), formamide, dimethyl sulfoxide, Tween 20, and bovine serum albumin have been used as LAMP additives. In our study, TMAC was presented as a promising additive for suppressing non-specific amplification in LAMP.The online version contains supplementary material available at 10.1007/s13206-022-00070-3.

This study presents an easy paper-plastic hybrid microfluidic chip fabrication method that explored the use of oven baking a wax-printed pattern for microfluidic channel assembly combined with the use of a double-sided adhesive tape for layer binding. More specifically, the method includes printing of a wax pattern onto the CA film & oven baking of the pattern along with the backed NC membrane at 120°C for 2.5 minutes. The porous nature of the NC membrane allows the wax pattern to enter into its pores during the baking process and binds the backed NC membrane with the CA film. Attachment of the engraved PMMA layer was performed to increase the structural support. The engraved hole of the layer allows the conjugate pad with space for its integration into the system. Moreover, the antibodies required for the integration of the chip with the LFIA were selected by enzyme-linked immunosorbent assay (ELISA). A CA film, an NC membrane, and a PMMA sheet were used to develop a microfluidic chip that can be integrated with a sandwich format lateral flow immunoassay used to detect dengue non-structural 1 protein. The fabricated chip was able to successfully detect a concentration of dengue non-structural 1 protein of at least 84.66 ng/mL.

This research aims a continuous and uniform oxygen tensions and oxygen gradients supply in microfluidic cell culture chip based micro-bioreactor without any external pumps by modifying the existing siphon based perfusion strategy using conventional tools to control constant hydrostatic pressure for constant fluid flow rate. In this study, the microfluidic based micro-bioreactor is fabricated using a polydimethylsiloxane (PDMS) replication process. The micro-bioreactor chip is composed of simple oxygen perfusion setup connecting to capillary-like branched microchannels and a cell culture and support loading area. The function of the new pump-less fluid perfusion in microfluidic cell culture chip and maintains constant oxygen supply in the cell culture area has been experimentally evaluated. And the results demonstrate that this proposed microfluidic flow system in a micro-bioreactor is proved to provide a linear distribution of oxygen throughout the cell culture area without any external and internal interference. Also, oxygen diffusion into the culture area through a microscale channel has been successfully established by the constant hydraulic pressure controlled by siphoning effect. Such flow system was used in a PDMS based microfluidic micro-bioreactor design to provide the high-throughput oxygen diffusion and perfusion, and the uniform oxygen/nutrient distribution continuously supplied for dermal fibroblast cell culture. This could be a potential and effective model to be incorporated into tissue regeneration studies, drug screening model, and in cancer tissue model studies for understanding angiogenesis, where oxygen tension and perfusion cultures play important roles.

We report on the use of a complementary metal oxide semiconductor (CMOS) image sensor in an immunodiagnostic system for detecting the human immunodeficiency virus (HIV). It is based on photon counting and the interaction of the HIV antigen (Ag) with respective antibodies, which are deposited in various thicknesses on indium nanoparticles (InNPs) substrate. The sensor measures the number of photons that depends on the concentration of HIV Ag and converts them into digital numbers. Photons are refracted on the protein adsorbed InNP substrate and hit the CMOS image sensor surface based on the Ag concentration. Topographical studies such as field emission scanning electron microscopy (FE-SEM) and fluorescence microscopy images are demonstrated the reliability of this scheme. Also, the UV-spectral studies proved the efficiency of the analysis with InNP substrate. The sensor is simple, compact, highly specific and accurate. Also, it can detect HIV at levels as low as 10 fg mL−1. Therefore, the sophisticated system of the CMOS image sensor based immunodetection now requires point-of-care (POC) diagnosis.