In vitro analysis of multiple blood flow determinants using red blood cell dynamics under oscillatory flow
ANALYST
Authors: Isiksacan, Ziya; Serhatlioglu, Murat; Elbuken, Caglar
Abstract
The flow behavior of blood is determined mainly by red blood cell (RBC) deformation and aggregation as well as blood viscoelasticity. These intricately interdependent parameters should be monitored by healthcare providers to understand all aspects of circulatory flow dynamics under numerous cases including cardiovascular and infectious diseases. Current medical instruments and microfluidic systems lack the ability to quantify these parameters all at once and in physiologically relevant flow conditions. This work presents a handheld platform and a measurement method for quantitative analysis of multiple of these parameters from 50 mu l undiluted blood inside a miniaturized channel. The assay is based on an optical transmission analysis of collective RBC deformation and aggregation under near-infrared illumination during a 1 s damped oscillatory flow and at stasis, respectively. Measurements with blood of different hemo-rheological properties demonstrate that the presented approach holds a potential for initiating simultaneous and routine on-chip blood flow analysis even in resource-poor settings.
Heart Valves Cross-Linked with Erythrocyte Membrane Drug-Loaded Nanoparticles as a Biomimetic Strategy for Anti-coagulation, Anti-inflammation, Anti-calcification, and Endothelialization
ACS APPLIED MATERIALS & INTERFACES
Authors: Hu, Cheng; Luo, Rifang; Wang, Yunbing
Abstract
In recent years, valvular heart disease has become a serious disease threatening human life and is a major cause of death worldwide. However, the glutaraldehyde (GLU)-treated biological heart valves (BHVs) fail to meet all requirements of clinical application due to disadvantages such as valve thrombus, cytotoxicity, endothelialization difficulty, immune response, and calcification. Encouragingly, there are a large number of carboxyls as well as a few amino groups on the surface of GLU-treated BHVs that can be modified to enhance biocompatibility. Inspired by natural biological systems, we report a novel approach in which the heart valve was cross-linked with erythrocyte membrane biomimetic drug-loaded nanoparticles. Such modified heart valves not only preserved the structural integrity, stability, and mechanical properties of the GLU-treated BHVs but also greatly improved anti-coagulation, anti-inflammation, anti-calcification, and endothelialization. The in vitro results demonstrated that the modified heart valves had long-term anti-coagulation properties and enhanced endothelialization processes. The modified heart valves also showed good biocompatibility, including blood and cell biocompatibility. Most importantly, the modified heart valves reduced the TNF-alpha levels and increased IL-10 compared to GLU-treated BHVs. In vivo animal experiments also confirmed that the modified heart valves had an ultrastrong resistance to calcification after implantation in rats for 120 days. The mechanism of anti-calcification in vivo was mainly due to the controlled release of anti-inflammatory drugs that reduced the inflammatory response after valve implantation. In summary, this therapeutic approach based on BHVs cross-linking with erythrocyte membrane biomimetic nanoparticles sparks a novel design for valvular heart disease therapy.