Performance of a Hydrogel Coated Nitinol with Oligonucleotide-Modified Nanoparticles Within Turbulent Conditions of Blood-Contacting Devices

Abstract

Introduction: Hydrogels offer a wide range of applications in the antithrombotic modification of biomedical devices. The functionalization of these hydrogels with potentially drug-laden nanoparticles in the context of deviceassociated turbulence is critically under-studied. Thus, the purpose of this study was to use a hydrogel-coating nitinol surface as a model to understand the functions of hydrogels and the capture of nanoparticles under clinically relevant flow conditions.

Methods: Nitinol was coated by an oligonucleotide (ON) functionalized hydrogel. Nanoparticles were functionalized with complementary oligonucleotides (CONs). The capture of CONfunctionalized nanoparticles by the ON-functionalized hydrogel surfaces was studied under both static and dynamic attachment conditions. Fluorescent-labelling of nanoparticles was utilized to assess capture efficacy and resistance to removal by device-relevant flow conditions.

Results: The specificity of the ON-CON bond was verified, exhibiting a dose-dependent attachment response. The hydrogel coating was resistant to stripping by flow, retaining >95% after exposure to one hour of turbulent flow. Attachment of nanoparticles to the hydrogel was higher in the static condition than under laminar flow (p < 0.01), but comparable to that of attachment under turbulent flow. Modified nitinol samples underwent one hour of flow treatment under both laminar and turbulent regimes and demonstrated decreased nanoparticle loss following static conjugation rather than turbulent conjugation (36.1% vs 53.8%, p < 0.05). There was no significant difference in nanoparticle functionalization by upstream injection between laminar and turbulent flow.

Conclusion: The results demonstrate promising potential of hydrogelfunctionalized nitinol for capturing nanoparticles using nucleic acid hybridization. The hydrogel structure and ONCON bond integrity both demonstrated a resistance to mechanical damage and loss of biomolecular functionalization by exposure to turbulence. Further investigation is warranted to highlight drug delivery and antithrombogenic modification applications of nanoparticle-functionalized hydrogels.

Keywords: Aptamers; Biomaterial; Flow; Surface; Turbulence.