ABSTRACT
Liquid biopsy is a technology that exhibits potential to detect cancer early,monitor therapies,and predict cancer prognosis due to its unique characteristics,including noninvasive sampling and real-time analysis.Circulating tumor cells(CTCs)and extracellular vesicles(EVs)are two important components of circu-lating targets,carrying substantial disease-related molecular information and playing a key role in liquid biopsy.Aptamers are single-stranded oligonucleotides with superior affinity and specificity,and they can bind to targets by folding into unique tertiary structures.Aptamer-based microfluidic platforms offer new ways to enhance the purity and capture efficiency of CTCs and EVs by combining the advantages of microfluidic chips as isolation platforms and aptamers as recognition tools.In this review,we first briefly introduce some new strategies for aptamer discovery based on traditional and aptamer-based micro-fluidic approaches.Then,we subsequently summarize the progress of aptamer-based microfluidics for CTC and EV detection.Finally,we offer an outlook on the future directional challenges of aptamer-based microfluidics for circulating targets in clinical applications.
ABSTRACT
OBJECTIVE:To establish a method for the content determination of isoniazid in Isoniazid tablet. METHODS:Mi-crofluidic chip with contactless conductivity detection was adopted. The effects of electrophoresis parameters,such as the variety, concentration,pH,additive types and dosage,injection time and separation voltage on the separation detection were explored. RE-SULTS:The optimized buffer system was 1.86 mmol/L citrate-0.14 mmol/L sodium citrate buffer solution (pH3.0),no additive , the injection time was 20 s and the separation voltage was 2.5 kV. In the optimal conditions,the linear range of isoniazid was 10-200 μg/mL(r=0.9993);the limits of quantification and detection were 8.0 μg/mL and 2.4 μg/mL;RSDs of precision,stability and reproducibility tests were lower than 2.0%;recovery was 97.8%-102.9%(RSD=1.9%,n=9). CONCLUSIONS:The method is rapid and simple,and suitable for the content determination of isoniazid in Isoniazid tablet.
ABSTRACT
The mature fruits of Aristolochia debilis, known in China by the name, "Madouling" has been popularly prescribed in Asia, particularly in China, to treat a range of conditions including gynaecological problems, arthritis and wound healing. This study was aimed to evaluate the potential effect of Madouling on the cytochrome P450 [CYP] isozymes in vitro in microsomal fractions and in vivo in rats. The influence of Madouling on CYPs activity was first explored by an in vitro method of estimating levels of four respective metabolites in rat liver microsomes. The results were re-examined in vivo in rats by using a cocktail approach involving the probe drugs theophylline, tolbutamide, chlorzoxazone and dapsone. Pharmacokinetics of the four substrates was used to analyze the activities of the targeting isozymes. In vitro study revealed that Madouling decreased the activity of CYP1A2, 3A1 and 2E1. However, no significant influence on CYP2C6 was found. These results coincided with those of in vivo study to a great degree except that in vivo estimation the herb didn't inhibit CYP1A2 significantly. From the data obtained, Madouling is suggested as a c and idate for clinically significant CYP interactions. Drug co-administrated with Madouling may need dose adjustment.
ABSTRACT
With the continuous development in microfluidic fabrication technology, microfluidic analysis has evolved from a concept to one of research frontiers in last twenty years. The research of enzymes and enzyme inhibitors based on microfluidic devices has also made great progress. Microfluidic technology improved greatly the analytical performance of the research of enzymes and enzyme inhibitors by reducing the consumption of reagents, decreasing the analysis time, and developing automation. This review focuses on the development and classification of enzymes and enzyme inhibitors research based on microfluidic devices.
ABSTRACT
A new on-column conductivity detection for microchip capillary based on the accessional solution conductor between separation channel and electrodes was designed. In this detection, the carrier electrolyte solution was chosen as conductor to eliminate large drifts of the detection signals, that because different composition or concentration can lead to transport processes(diffusion and electromigration) between the carrier electrolyte solution and mediator. The separation channel incorporated a dual-T and a crux-channel, dual-T was used for sample introduction, and the crux-channel was used for detection. The sensing electrodes connected to separation channel through the crux-channel and obtained the potential different of conductivity. This method avoids integrating the sensing electrodes directly within the separation channel and prevents any direct contact of the electrodes with the sample. It not only avoids electrode reactions but also is convenient for washing and replacing electrodes. In addition, the signals, contrary to contactless conductivity detection, can be detected in the low excitation voltage(2.5-4.0 V) and frequency(700-1700 Hz) range. In the buffer solution of 15 mmol/L MES-His(pH 5.8), the detection limits was 0.5 and 0.1 μmol/L for K+ and Na+.