Are peristaltic pumps as reliable as syringe pumps for metabolic research? Assessment of accuracy, precision, and metabolic kinetics

Fluid flow to mimic organ function in 3D in vitro models

Many different strategies can be found in the literature to model organ physiology, tissue functionality, and disease in vitro; however, most of these models lack the physiological fluid dynamics present in vivo. Here, we highlight the importance of fluid flow for tissue homeostasis, specifically in vessels, other lumen structures, and interstitium, to point out the need of perfusion in current 3D in vitro models. Importantly, the advantages and limitations of the different current experimental fluid-flow setups are discussed. Finally, we shed light on current challenges and future focus of fluid flow models applied to the newest bioengineering state-of-the-art platforms, such as organoids and organ-on-a-chip, as the most sophisticated and physiological preclinical platforms.

Syringe-pump-induced fluctuation in all-aqueous microfluidic system implications for flow rate accuracy

We report a new method to display the minute fluctuations induced by syringe pumps on microfluidic flows by using a liquid-liquid system with an ultralow interfacial tension. We demonstrate that the stepper motor inside the pump is a source of fluctuations in microfluidic flows by comparing the frequencies of the ripples observed at the interface to that of the pulsation of the stepper motor. We also quantify the fluctuations induced at different flow rates, using syringes of different diameters, and using different syringe pumps with different advancing distances per step. Our work provides a way to predict the frequency of the fluctuation that the driving syringe pump induces on a microfluidic system and suggests that syringe pumps can be a source of fluctuations in microfluidic flows, thus contributing to the polydispersity of the resulting droplets.

Protective effect of hesperidin, a citrus flavanoglycone, against γ-radiation-induced tissue damage in Sprague-Dawley rats

The present study was designed to evaluate the radioprotective effect of hesperidin, a citrus flavanoglycone, against γ-radiation-induced cellular damage in the liver, heart, and kidney of rats. Whole-body γ-radiation exposure (5 Gy) of healthy adult rats resulted in cellular damage and oxidative stress manifested as increased levels of serum marker enzymes, lipid peroxidation, and fibrosis in the tissues, accompanied by depletion of cellular glutathione and abnormal alteration in the levels of lysosomal enzymes. Treatment with hesperidin (50 and 100 mg/kg, p.o.) for 7 days was found to offer significant protection against γ-radiation-induced toxicity in the tissues, which was evident by the improved status of most of the parameters investigated. Further, the histological examination of periodic acid-Schiff-stained tissue sections of animals treated with hesperidin following radiation exposure showed minimal necrotic damage with a recovery pattern in a dose-dependent manner compared with radiation-exposed animals. The results of our study show that administration of hesperidin offers effective protection against γ-radiation-induced cellular damage and oxidative stress in rats.