Cellular coating of the left ventricular assist device textured polyurethane membrane reduces adhesion of Staphylococcus aureus

Drug Delivery Systems in Regenerative Medicine: An Updated Review

Modern drug discovery methods led to evolving new agents with significant therapeutic potential. However, their properties, such as solubility and administration-related challenges, may hinder their benefits. Moreover, advances in biotechnology resulted in the development of a new generation of molecules with a short half-life that necessitates frequent administration. In this context, controlled release systems are required to enhance treatment efficacy and improve patient compliance. Innovative drug delivery systems are promising tools that protect therapeutic proteins and peptides against proteolytic degradation where controlled delivery is achievable. The present review provides an overview of different approaches used for drug delivery.

The Biocompatibility Challenges in the Total Artificial Heart Evolution

There are limited therapeutic options for final treatment of end-stage heart failure. Among them, implantation of a total artificial heart (TAH) is an acceptable strategy when suitable donors are not available. TAH development began in the 1930s, followed by a dramatic evolution of the actuation mechanisms operating the mechanical pumps. Nevertheless, the performance of TAHs has not yet been optimized, mainly because of the low biocompatibility of the blood-contacting surfaces. Low hemocompatibility, calcification, and sensitivity to infections seriously affect the success of TAHs. These unsolved issues have led to the withdrawal of many prototypes during preclinical phases of testing. This review offers a comprehensive analysis of the pathophysiological events that may occur in the materials that compose TAHs developed to date. In addition, this review illustrates bioengineering strategies to prevent these events and describes the most significant steps toward the achievement of a fully biocompatible TAH.

Plasma functionalization of polycarbonaturethane to improve endothelialization—Effect of shear stress as a critical factor for biocompatibility control

Medical devices made of polycarbonaturethane (PCU) combine excellent mechanical properties and little biological degradation, but restricted hemocompatibility. Modifications of PCU might reduce platelet adhesion and promote stable endothelialization. PCU was modified using gas plasma treatment, binding of hydrogels, and coupling of cell-active molecules (modified heparin, anti-thrombin III (ATIII), argatroban, fibronectin, laminin-nonapeptide, peptides with integrin-binding arginine-glycine-aspartic acid (RGD) motif). Biocompatibility was verified with static and dynamic cell culture techniques. Blinded analysis focused on improvement in endothelial cell (EC) adhesion/proliferation, anti-thrombogenicity, reproducible manufacturing process, and shear stress tolerance of ECs. EC adhesion and antithrombogenicity were achieved with 9/35 modifications. Additionally, 6/9 stimulated EC proliferation and 3/6 modification processes were highly reproducible for endothelialization. The latter modifications comprised immobilization of ATIII (A), polyethyleneglycole-diamine-hydrogel (E) and polyethylenimine-hydrogel connected with modified heparin (IH). Under sheer stress, only the IH modification improved EC adhesion within the graft. However, ECs did not arrange in flow direction and cell anchorage was restricted. Despite large variation in surface modification chemistry and improved EC adhesion under static culture conditions, additional introduction of shear stress foiled promising preliminary data. Therefore, biocompatibility testing required not only static tests but also usage of physiological conditions such as shear stress in the case of vascular grafts.

Biomedical Applications of Biodegradable Polymers

Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. In order to fit functional demand, materials with desired physical, chemical, biological, biomechanical and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.

Surface coatings for ventricular assist devices

This article focuses on the surface engineering of ventricular assist devices (VADs) for the treatment of heart failure patients, which involves the modification of surfaces contacting blood in order to improve the blood compatibility (hemocompatibility) of the VADs. Following an introduction to the categorization and the complications of VADs, this article pays attention on the hemocompatibility, applications and limitations of six types of surface coatings for VADs: titanium nitride coatings, diamond-like carbon coatings, 2-methacryloyloxyethyl phosphorylcholine polymer coatings, heparin coatings, textured surfaces and endothelial cell linings. In particular, diamond-like coatings and heparin coatings are the most commonly used for VADs owing to their excellent hemocompatibility, durability and technical maturity. For high performance and a long lifetime of VADs, surface modification with coatings to ensure hemocompatibility is as important as the mechanical design of the device.

Destination therapy: does progress depend on left ventricular assist device development?

The role of therapy using mechanical circulatory support devices has evolved rapidly over the last two decades. New developments in the field achieved smaller adverse events, but, currently, only minor improvements in survival were observed in published observational data. The authors discuss the development of mechanical circulatory support devices as a "destination therapy" option for patients who have end-stage heart failure and are ineligible for heart transplantation as it relates to left ventricular assist device development.