Characterization of elastomeric scaffolds developed for tissue engineering applications by compression and nanoindentation tests, μ-Raman and μ-Brillouin spectroscopies.

Géraldine Rohman,Didier Lutomski,Salah Ramtani,Philippe Djemia,Florent Tétard,Yves Roussigné,Credson Langueh,Sylvie Changotade,Fréderic Caupin

doi:10.1364/boe.10.001649

Abstract

In tissue engineering, porous biodegradable scaffolds are developed with morphological, chemical and mechanical properties to promote cell response. Therefore, the scaffold characterization at a (sub)micrometer and (bio)molecular level is paramount since cells are sensitive to the chemical signals, the rigidity, and the spatial structuring of their microenvironment. In addition to the analysis at room temperature by conventional quasi-static (0.1-45 Hz) mechanical tests, the ultrasonic (10 MHz) and μ-Brillouin inelastic light scattering (13 GHz) were used in this study to assess the dynamical viscoelastic parameters at different frequencies of elastomeric scaffolds. Time-temperature superposition principle was used to increase the high frequency interval (100 MHz-100 THz) of Brillouin experiments providing a mean to analyse the viscoelastic behavior with the fractional derivative viscoelastic model. Moreover, the μ-Raman analysis carried out simultaneously during the μ-Brillouin experiment, gave the local chemical composition.

Highlights

The aim of tissue engineering is to develop porous biodegradable structures adequate for the migration, the adhesion, the proliferation and the differentiation of cells seeded in the material before the implantation or recruited from the implantation site [1]
This study shows the potential of the combination use of the nanoindentation tests, the pulse-echo ultrasonic technique and of the μ-Brillouin spectroscopy vs temperature to assess some dynamical viscoelastic parameters of elastomeric scaffolds at very different frequencies (Hz–100 THz)
A direct calculation considering the minimisation of a criterion based on the Kramers-Kronig relations has been proposed by Rouleau et al [20]. To partially overcome this difficulty, we considered the closest modulus measured at 10 MHz and room temperature by ultrasounds, as a reference, through which the used viscoelastic model have to go through and as closest as possible to the higher frequency data obtained by BLS

Summary

Introduction

The aim of tissue engineering is to develop porous biodegradable structures (scaffolds) adequate for the migration, the adhesion, the proliferation and the differentiation of cells seeded in the material before the implantation or recruited from the implantation site [1]. Surface chemistry has a huge impact on the local adhesion, the cell spreading and overall biocompatibility [6], while the mechanical properties in relation to the porosity influence the cell form, proliferation, and cortical stiffness [7]. It is of very high importance to be able to deeply characterize scaffolds at (sub)micrometer and (bio)molecular levels. For this purpose, μ-Raman spectroscopy is a technology increasingly used in the field of biomedical research. Μ-Raman spectroscopy is a technology increasingly used in the field of biomedical research This technique uses the inelastic scattering of light by matter to give informations related to the (bio)chemical composition of cells, tissues, and scaffolds [8]. Based on the analysis of the frequency spectrum (position and full width at half maximum of the inelastic peaks) of the light scattering

Methods

Results

Conclusion