Axon mimicking hydrophilic hollow polycaprolactone microfibres for diffusion magnetic resonance imaging

Feng-Lei Zhou,Zhanxiong Li,Julie E Gough,Penny L Hubbard Cristinacce,Geoff J.M Parker

doi:10.1016/j.matdes.2017.10.047

Abstract

Highly hydrophilic hollow polycaprolactone (PCL) microfibres were developed as building elements to create tissue-mimicking test objects (phantoms) for validation of diffusion magnetic resonance imaging (MRI). These microfibres were fabricated by the co-electrospinning of PCL-polysiloxane-based surfactant (PSi) mixture as shell and polyethylene oxide as core. The addition of PSi had a significant effect on the size of resultant electrospun fibres and the formation of hollow microfibres. The presence of PSi in both co-electrospun PCL microfibre surface and cross-section, revealed by X-ray energy dispersive spectroscopy (EDX), enabled water to wet these fibres completely (i.e., zero contact angle) and remained active for up to 12 months after immersing in water. PCL and PCL-PSi fibres with uniaxial orientation were constructed into water-filled phantoms. MR measurement revealed that water molecules diffuse anisotropically in the PCL-PSi phantom. Co-electrospun hollow PCL-PSi microfibres have desirable hydrophilic properties for the construction of a new generation of tissue-mimicking dMRI phantoms.

Highlights

The mobility of water molecules within tissue depends on the microstructure of the tissue
We investigate the feasibility of using poly[dimethylsiloxane-co[3-(2-(2-hydroxyethoxy)ethoxy) propyl] methylsiloxane], a non-ionic surfactant composed of polyoxyethlyene chains attached to siloxane chains, to enhance the hydrophilicity of PCL fibres
Co-electrospun PCL-polysiloxane-based surfactant (PSi) fibres were successfully applied in the field of tissue-mimicking phantoms filled with water for diffusion magnetic resonance imaging

Summary

Introduction

The mobility of water molecules within tissue depends on the microstructure of the tissue. Brain white matter and cardiac muscle are highly anisotropic fibrous tissues with diameters ranging from 0.1–20 μm [1,2,3,4,5] In both water diffuses more freely along the dominant fibre orientation and is hindered to different degrees in other directions, leading to diffusion anisotropy [5,6,7,8]. We were the first to use co-electrospun coreshell structured microfibres to construct brain white matter, grey matter and cardiac tissue mimicking phantoms for the calibration and validation of dMRI [5,16,17]; this has been extended to tumour cellmimicking phantom composed of hollow microspheres [18]. Hollow polypropylene (PP) filaments generated by melt spinning have been used to mimic white matter axons and to construct an MR brain phantom [19]

Methods

Results

Discussion

Conclusion