Biomaterials Based on Carbon Nanotube Nanocomposites of Poly(styrene-b-isobutylene-b-styrene): The Effect of Nanotube Content on the Mechanical Properties, Biocompatibility and Hemocompatibility

Maria A Rezvova,Evgeniia A Senokosova,Mariam Yu Khanova,Miraslau I Makarevich,Zinfer R Ismagilov,Evgeny A Ovcharenko,Olga S Efimova,Kirill Yu Klyshnikov,Tatiana V Glushkova,Sergei V Kostjuk,Dmitry M Russakov,Pavel A Nikishau,Valentina Yu Malysheva,Andrey P Nikitin,Viacheslav V Danilov,Tatiana N Akentieva,Vera G Matveeva

doi:10.3390/nano12050733

Abstract

Nanocomposites based on poly(styrene-block-isobutylene-block-styrene) (SIBS) and single-walled carbon nanotubes (CNTs) were prepared and characterized in terms of tensile strength as well as bio- and hemocompatibility. It was shown that modification of CNTs using dodecylamine (DDA), featured by a long non-polar alkane chain, provided much better dispersion of nanotubes in SIBS as compared to unmodified CNTs. As a result of such modification, the tensile strength of the nanocomposite based on SIBS with low molecular weight (Mn = 40,000 g mol–1) containing 4% of functionalized CNTs was increased up to 5.51 ± 0.50 MPa in comparison with composites with unmodified CNTs (3.81 ± 0.11 MPa). However, the addition of CNTs had no significant effect on SIBS with high molecular weight (Mn~70,000 g mol−1) with ultimate tensile stress of pure polymer of 11.62 MPa and 14.45 MPa in case of its modification with 1 wt% of CNT-DDA. Enhanced biocompatibility of nanocomposites as compared to neat SIBS has been demonstrated in experiment with EA.hy 926 cells. However, the platelet aggregation observed at high CNT concentrations can cause thrombosis. Therefore, SIBS with higher molecular weight (Mn~70,000 g mol−1) reinforced by 1–2 wt% of CNTs is the most promising material for the development of cardiovascular implants such as heart valve prostheses.

Highlights

We found that the increase of the carbon nanotubes (CNTs) content results in gradual improvement of the mechanical properties of SIBS with low molecular weight (Mn = 40,000 g mol–1 ) but the addition of CNTs had no significant effect on high molecular weight SIBS (Mn ~70,000 g mol−1 )
Two samples of SIBS were prepared by the sequential cationic polymerization of isobutylene and styrene with dicumyl chloride/TiCl4 /2,6-lutidine initiating system following the protocol mentioned in our previous study [30]
We assessed the influence of the method of CNT preparation and molecular weight of triblock copolymers of isobutylene with styrene on the mechanical properties, thermal stability and bio- and hemocompatibility of the obtained nanocomposites

Summary

Introduction

Nanomaterials 2022, 12, 733 practice due to the growth of the global cardiovascular disease burden [1]. Such devices improve the quality of human life by prolonging the functioning of the body systems beyond their expected duration. Synthetic biomaterials should exhibit high mechanical strength, chemical and enzymatic stability, and high hemocompatibility [2]. This necessity stimulates the development of new synthetic biomaterials with improved mechanical properties and biocompatibility. The development of new nanocomposites based on high-strength, biologically inert carbon based nanosized materials–carbon nanotubes (CNTs) can be one of the possible solutions [3]

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Discussion

Conclusion