Label-free magnetic resonance imaging to locate live cells in three-dimensional porous scaffolds

Abstract

Porous scaffolds are widely tested materials used for various purposes in tissue engineering. A critical feature of a porous scaffold is its ability to allow cell migration and growth on its inner surface. Up to now, there has not been a method to locate live cells deep inside a material, or in an entire structure, using real-time imaging and a non-destructive technique. Herein, we seek to demonstrate the feasibility of the magnetic resonance imaging (MRI) technique as a method to detect and locate in vitro non-labelled live cells in an entire porous material. Our results show that the use of optimized MRI parameters (4.7 T; repetition time ¼ 3000 ms; echo time ¼ 20 ms; resolution 39 Â 39 mm) makes it possible to obtain images of the scaffold structure and to locate live non-labelled cells in the entire material, with a signal intensity higher than that obtained in the culture medium. In the current study, cells are visualized and located in different kinds of porous scaffolds. Moreover, further development of this MRI method might be useful in several three-dimensional biomaterial tests such as cell distribution studies, routine qualitative testing methods and in situ monitoring of cells inside scaffolds.

An Open Source Image Processing Method to Quantitatively Assess Tissue Growth after Non-Invasive Magnetic Resonance Imaging in Human Bone Marrow Stromal Cell Seeded 3D Polymeric Scaffolds

“…Most conventional methods to study cell growth and distribution are based on destructive methods such as histological analysis and biochemical assays. Non-invasive imaging modalities are promising tools to non-destructively and ultimately longitudinally or continuously monitor tissue development in 3D scaffolds [9] , [30] . Magnetic resonance modalities have gained interest in the field of tissue engineering for several years.…”

“…First, nuclear magnetic resonance spectroscopy (NMR) has been applied to monitor metabolites in tissue engineered constructs [31] . More recently, MRI has been applied because of the capability to distinguish between several tissue types and densities such as collagens, mineralized tissues and soft tissues [8] , [12] , [17] , [30] , [32] – [34] . Contrast with a sub-mm scale resolution in MRI is obtained by variations in proton dynamics which results in different water proton transverse (T 2 ) relaxation times and magnetization transfer ratios [10] .…”

Effect of the drying process on the compressive strength and cell proliferation of hydroxyapatite‐derived scaffolds

“…Commercially available hydroxyapatite (HA) (HA Captal â S, Plasma Biotal, North Derbyshire, U.K.) was used to prepare inks for robocasting with a final solid content of 45 vol.%, following a procedure described in previous works. 15,16 Briefly, the HA powder was gradually added to an aqueous solution of a dispersant (Darvan â C, 1.5 wt% relative to powder content). Then, hydroxypropyl methylcellulose (Methocel F4M; Dow Chemical, Midland, MI) was added to the mixture to increase its viscosity.…”

A Perspective on the Clinical Translation of Scaffolds for Tissue Engineering

“…43 Advances in MRI, PET and multiphoton imaging techniques could facilitate the tracking of cells within scaffolds, as well as assessment of overall scaffold performance. 1,58,111 These imaging techniques would enable monitoring of non-transfected native cells, but sensitivity and resolution would need to be improved before this becomes clinically viable. Nevertheless, combining real-time monitoring within a therapy through leveraging advanced imaging strategies could enable more personalized and tunable therapies, along with “theranostic” approaches to sense disease state over the lifetime of the construct.…”