Simplified Pulse Reactor for Real-Time Long-Term In Vitro Testing of Biological Heart Valves

This paper demonstrates a modeling technique of prosthetic heart valves. In the modeling, a pumping cycle is divided into four phases, in which the state of the valve and flow is different. The pressure-flow relation across the valve is formulated separately in each phase. This technique is developed to build a mathematical model used in the real time estimation of the hemodynamic state under artificial heart pumping. The model built by this technique is simple enough for saving the computational time in the real time estimation. The model is described by the first-order ordinary differential equation with 12 parameters. These parameters can be uniquely determined beforehand from in-vitro experimental data. It is shown that the model can adapt, with sufficient accuracy, to a change in the practical pumping condition and the viscosity of the fluid in their practical range, and is also demonstrated that the estimated backflow volume by model agrees closely with the actual one.

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In Vitro Thrombogenicity Testing of Artificial Organs

The International Journal of Artificial Organs ◽

10.1177/039139889802100910 ◽

1998 ◽

Vol 21 (9) ◽

pp. 548-552 ◽

Cited By ~ 20

Author(s):

R. Paul ◽

O. Marseille ◽

E. Hintze ◽

L. Huber ◽

H. Schima ◽

...

Keyword(s):

Heart Valves ◽

Early Stage ◽

Thrombus Formation ◽

Testing Procedure ◽

Artificial Organs ◽

Coagulation System ◽

In Vitro Testing ◽

Animal Testing ◽

Thrombogenic Potential

Thromboembolic complications remain as one of the main problems for blood contacting artificial organs such as heart valves, bloodpumps and others. In vitro evaluation of thrombogenesis in prototypes has not previously been part of the standard evaluation of these devices. In comparison to hemolysis testing, evaluation of the thrombogenic potential is more difficult to perform because of the complexity of the blood coagulation system. We present an in vitro testing procedure that allows the accelerated examination of the thrombogenic potential of different types of blood pumps. Additionally, first results are presented that indicate the reliability of the accelerated clotting test for mechanical heart valves. Results for the centrifugal pump BioMedicus and two microaxial pumps have shown typical thrombus formation at locations such as bearings. The results indicate that the accelerated clotting test is an excellent addition to the much more expensive animal testing of artificial organs or assist devices. In vitro testing permits studies of thrombus formation to be performed at an early stage and at low costs and also facilitates a more precise investigation of device areas known to be potential hot spots for thrombus formation.

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Loading Graphene Quantum Dots into Optical-Magneto Nanoparticles for Real-Time Tracking In Vivo

Materials ◽

10.3390/ma12132191 ◽

2019 ◽

Vol 12 (13) ◽

pp. 2191 ◽

Cited By ~ 3

Author(s):

Yu Wang ◽

Nan Xu ◽

Yongkai He ◽

Jingyun Wang ◽

Dan Wang ◽

...

Keyword(s):

Quantum Dots ◽

Real Time ◽

Fluorescent Dyes ◽

Graphene Quantum Dots ◽

Shell Nanoparticles ◽

One Pot ◽

Real Time Tracking

Fluorescence imaging offers a new approach to visualize real-time details on a cellular level in vitro and in vivo without radioactive damage. Poor light stability of organic fluorescent dyes makes long-term imaging difficult. Due to their outstanding optical properties and unique structural features, graphene quantum dots (GQDs) are promising in the field of imaging for real-time tracking in vivo. At present, GQDs are mainly loaded on the surface of nanoparticles. In this study, we developed an efficient and convenient one-pot method to load GQDs into nanoparticles, leading to longer metabolic processes in blood and increased delivery of GQDs to tumors. Optical-magneto ferroferric oxide@polypyrrole (Fe3O4@PPy) core-shell nanoparticles were chosen for their potential use in cancer therapy. The in vivo results demonstrated that by loading GQDs, it was possible to monitor the distribution and metabolism of nanoparticles. This study provided new insights into the application of GQDs in long-term in vivo real-time tracking.

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