Analysis of the Biochemical Reaction Status by Real-Time Monitoring Molecular Diffusion Behaviors Using a Transistor Biosensor Integrated with a Microfluidic Channel.

Traditional methods of monitoring biochemical reactions measure certain detectable reagents or products while assuming that the undetectable species follow the stoichiometry of the reactions. Here, based upon the metal-oxide thin-film transistor (TFT) biosensor, we develop a real-time molecular diffusion model to benchmark the concentration of the reagents and products. Using the nicotinamide adenine dinucleotide (NADH)-oxaloacetic acid with the enzyme of malate dehydrogenase as an example, mixtures of different reagent concentrations were characterized to extract the ratio of remaining concentrations between NAD+ and NADH. We can thus obtain the apparent equilibrium constant of the reaction, (8.06 ± 0.61) × 104. Because the whole analysis was conducted using a TFT sensor fabricated using a semiconductor process, our approach has the advantages of exploring biochemical reaction kinetics in a massively parallel manner.

Total synthesis of landomycins Q and R and related core structures for exploration of the cytotoxicity and antibacterial properties.

Herein, we report the total synthesis of landomycins Q and R as well as the aglycone core, namely anhydrolandomycinone and a related core analogue. The synthesis features an acetate-assisted arylation method for construction of the hindered B-ring in the core component and a one-pot aromatization-deiodination-denbenzylation procedure to streamline the global functional and protecting group manuipulation. Subsequent cytotoxicity and antibacterial studies revealed that the landomycin R is a potential antibacterial agent against methicillin-resistant Staphylococcus aureus.

Review of Integrated Optical Biosensors for Point-Of-Care Applications.

This article reviews optical biosensors and their integration with microfluidic channels. The integrated biosensors have the advantages of higher accuracy and sensitivity because they can simultaneously monitor two or more parameters. They can further incorporate many functionalities such as electrical control and signal readout monolithically in a single semiconductor chip, making them ideal candidates for point-of-care testing. In this article, we discuss the applications by specifically looking into point-of-care testing (POCT) using integrated optical sensors. The requirement and future perspective of integrated optical biosensors for POC is addressed.

Characterizations of protein-ligand reaction kinetics by transistor-microfluidic integrated sensors.

Understanding the binding affinities and kinetics of protein-ligand interactions using a label-free method is crucial for identifying therapeutic candidates in clinical diagnostics and drug development. In this work, the IGZO-TFT (thin-film transistor) biosensor integrated with a tailored microfluidic chip was developed to explore binding kinetics of protein-ligand biochemical interactions in the real-time manner. The IGZO-TFT sensor extracts the binding characteristics through sensing biomolecules by their electrical charges. Using lysozyme and tri-N-acetyl-D-glucosamine (NAG3) as an example, we established a procedure to obtain the parameters, such as the dissociation constant, Kd, and association rate constant, ka, that are critical to biochemical reactions. The correlation between the lysozyme concentration and TFT drain current signal was first constructed. Next, solutions of lysozyme and NAG3 of different mixing ratios were prepared. They were pre-mixed for various periods of reaction time before applying to the TFT sensor to extract signals of lysozyme molecules and the concentration remaining. With the knowledge of drain current changes at different reaction times, ka and Kd can be obtained. The values from our experiment are comparable to other methods, which suggests the proposed approach can be employed to explore protein-ligand interaction kinetics in the massively parallel manner if the TFT array is considered.