Incorporation of Controlled Release Systems Improves the Functionality of Biodegradable 3D Printed Cardiovascular Implants.

New horizons in cardiovascular research are opened by using 3D printing for biodegradable implants. This additive manufacturing approach allows the design and fabrication of complex structures according to the patient's imaging data in an accurate, reproducible, cost-effective, and quick manner. Acellular cardiovascular implants produced from biodegradable materials have the potential to provide enough support for tissue regeneration while gradually being replaced by neo-autologous tissue.

Carbon nanotubes as a nitric oxide nano-reservoir improved the controlled release profile in 3D printed biodegradable vascular grafts.

Small diameter vascular grafts (SDVGs) are associated with a high failure rate due to poor endothelialization. The incorporation of a nitric oxide (NO) releasing system improves biocompatibility by using the NO effect to promote endothelial cell (EC) migration and proliferation while preventing bacterial infection. To circumvent the instability of NO donors and to prolong NO releasing, S-nitroso-N-acetyl-D-penicillamine (SNAP) as a NO donor was loaded in multi-walled carbon nanotubes (MWCNTs).

4D Printing Applications in the Development of Smart Cardiovascular Implants.

Smart materials are able to react to different stimuli and adapt their shape to the environment. Although the development of 3D printing technology increased the reproducibility and accuracy of scaffold fabrication, 3D printed scaffolds can still be further improved to resemble the native anatomy. 4D printing is an innovative fabrication approach combining 3D printing and smart materials, also known as stimuli-responsive materials.

Additively manufactured small-diameter vascular grafts with improved tissue healing using a novel SNAP impregnation method.

The vascular network has a complex architecture such as branches, curvatures, and bifurcations which is even more complicated in view of individual patients' defect anatomy requiring custom-specifically designed vascular implants. In this work, 3D printing is used to overcome these challenges and a new shorter impregnation method was developed to incorporate S-nitroso-N-acetyl-d-penicillamine (SNAP) as a nitric oxide (NO) donor to printed grafts. The 3D-printed small-diameter vascular grafts (SDVGs) were impregnated with SNAP solution during SNAP synthesis (S1) or with SNAP dissolved in methanol (S2).

Controlled NO-Release from 3D-Printed Small-Diameter Vascular Grafts Prevents Platelet Activation and Bacterial Infectivity.

Thrombogenicity and bacterial infectiveness are the most common complications for foreign blood contacting surfaces associated with functional failure of small-diameter vascular grafts (SDVGs). In this work, novel bactericidal and nonthrombogenic SDVGs were manufactured via 3D-printing technology, thus producing a controlled nitric oxide (NO) release coating. -Nitroso--acetyl-D-penicillamine (SNAP) was synthesized as an NO-donor, and three biomedical grade composite matrixes of poly(ethylene glycol) (PEG)-SNAP, polycaprolactone (PCL)-SNAP, and PEG-PCL-SNAP were validated for water uptake and NO-release kinetics.

Nitric oxide-releasing vascular grafts: A therapeutic strategy to promote angiogenic activity and endothelium regeneration.

Small-diameter vascular grafts (SDVGs) are associated with a high incidence of failure due to infection and obstruction. Although several vascular grafts are commercially available, specific anatomical differences of defect sites require patient-based design and fabrication. Design and fabrication of such custom-tailored grafts are possible with 3d-printing technology.

Decellularized ECM-derived bioinks: Prospects for the future.

Decellularization aims to remove cells from tissue ultrastructure while preserving the mechanical and biological properties, which makes the decellularized extracellular matrix (dECM) an appropriate scaffold for tissue engineering applications. Three-dimensional (3D) bioprinting technology as a reproducible and accurate method can print the combination of ECM and autologous cells layer by layer to fabricate patient based cell-laden structures representing the intrinsic cues of natural ECM. This review defines ECM, classifies decellularization agents and techniques, and explains different sources of ECM.

Nitric oxide secretion by endothelial cells in response to fluid shear stress, aspirin, and temperature.

Current vascular grafts have a high incidence of failure, especially in the grafts less than 6 mm in diameter, due to thrombus formation. Nitric oxide (NO) is released by endothelium and has some beneficial influences such as an antithrombotic effect. We hypothesized that applying different shear stress regiments and low temperature or aspirin would result in an increase in the amount of NO release from human umbilical vein endothelial cells (HUVECs) and decrease in platelet aggregation in the same manner as expected in vivo.