Polydopamine Modified TiO₂ Nanotube Arrays for Long-Term Controlled Elution of Bivalirudin and Improved Hemocompatibility

Abstract

Sustained and controllable release characteristics are pivotal factors for novel drug delivery technologies. TiO nanotube arrays prepared by self-ordering electrochemical anodization are attractive for the development of biomedical devices for local drug delivery applications. In this work, several layers of polydopamine (PDA) were deposited to functionalize TiO nanotube arrays. The anticoagulant drug bivalirudin (BVLD) was used as a model drug. PDA extended the release period of BVLD and maintained a sustained release kinetic. Depending on the number of PDA layers, the release characteristics of BVLD improved, as there was a reduced burst release (from 45% to 11%) and extended overall release period from 40 days to more than 300 days in the case of 5 layers. Besides, the BVLD loaded 5-layer PDA coating maintained the high bioactivity of BVLD and effectively reduced the thrombosis formation by inhibition of the adhesion and denaturation of fibrinogen, platelets, and other blood components. Both in vitro and ex vivo blood evaluation results demonstrated that this coating significantly improved the hemocompatibility. These results confirmed the capability of PDA fitted TiO nanotube systems to be applied for local drug delivery over an extended period with well retained bioactivity and predictable release kinetics.

Endothelium-Mimicking Multifunctional Coating Modified Cardiovascular Stents via a Stepwise Metal-Catechol-(Amine) Surface Engineering Strategy

“…For blood-contacting implants, the thrombus formation is still a practical problem. The adsorption/activation of fibrinogen (Fg) and adhesion/activation of platelets are the two most fundamental contributors to thrombus formation [51]. As shown in Figure 6(a), both Hep and Hep@NO surfaces significantly decreased the adsorption and activation of Fg, determined by immunochemistry with universal and conformation-specific antibodies.…”

“…To further check the synergetic effects of heparin and NO in reducing thrombogeni-city, we performed ex vivo and in vivo antithrombogenic evaluations. An arteriovenous shunt model was applied for the ex vivo antithrombogenic test, as reported before [51]. The custom-built extracorporeal circuit (ECC) was set up by connecting left carotid artery and right external jugular to guarantee blood flow, with samples rolled and installed in the middle part of ECC (Figure 7(a)).…”

“…Ex Vivo Circulation Thrombogenicity Test. ECC was conducted by connecting the left carotid artery of New Zealand white rabbits (6, 2.5~3.5 kg) with the right jugular vein in accordance with guidelines as reported before [51]. Samples prepared on 316L SS foils (0:8 × 1 mm 2 ) were rolled and installed in the tube.…”

Applications of Polydopamine-Modified Scaffolds in the Peripheral Nerve Tissue Engineering

“…After PDA is attached to materials, it performs as a secondary platform for functional molecules (drugs or growth factors, silver nanoparticles, and proteins) binding to the surface (Lee et al, 2009;Ball et al, 2011;Liang et al, 2019). In addition, thicker layers of PDA can bind more drugs with much longer release time (several hundred days), which endows the drugs with sustained release (Yang et al, 2018).…”

Combined Infection Control and Enhanced Osteogenic Differentiation Capacity on Additive Manufactured Ti‐6Al‐4V are Mediated via Titania Nanotube Delivery of Novel Biofilm Inhibitors

“…As demonstrated in this study (Figure 2A), nanotube‐mediated drug delivery performance is affected by different parameters such as nanotube dimensions, as well as the drug properties including hydrophilicity and molecular size, all of which most likely affect drug molecule diffusion in this case. [ 51 ] Furthermore, additional surface treatments such as polymer coating [ 25,52,53 ] and chemical tether [ 54 ] are also under investigation to extend the release profile. Other more advanced nanotube‐based delivery strategies such as pH‐, temperature‐, light‐, radiofrequency‐, and magnetic‐stimulated drug delivery could further facilitate targeted spatio‐temporal controlled delivery.…”