Graphene Oxide and Reduced Graphene Oxide Nanoflakes Coated with Glycol Chitosan, Propylene Glycol Alginate, and Polydopamine: Characterization and Cytotoxicity in Human Chondrocytes.

Madina Telkhozhayeva,Lorenzo Vannozzi,Efrat Shawat Avraham,Gilbert Daniel Nessim,Eti Teblum,Alina Yarmolenko,Rajashree Konar,Enrico Catalano,Leonardo Ricotti

doi:10.3390/nano11082105

Madina Telkhozhayeva, Lorenzo Vannozzi + Show 7 more

Open Access

https://doi.org/10.3390/nano11082105

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Abstract

Recently, graphene and its derivatives have been extensively investigated for their interesting properties in many biomedical fields, including tissue engineering and regenerative medicine. Nonetheless, graphene oxide (GO) and reduced GO (rGO) are still under investigation for improving their dispersibility in aqueous solutions and their safety in different cell types. This work explores the interaction of GO and rGO with different polymeric dispersants, such as glycol chitosan (GC), propylene glycol alginate (PGA), and polydopamine (PDA), and their effects on human chondrocytes. GO was synthesized using Hummer’s method, followed by a sonication-assisted liquid-phase exfoliation (LPE) process, drying, and thermal reduction to obtain rGO. The flakes of GO and rGO exhibited an average lateral size of 8.8 ± 4.6 and 18.3 ± 8.5 µm, respectively. Their dispersibility and colloidal stability were investigated in the presence of the polymeric surfactants, resulting in an improvement in the suspension stability in terms of average size and polydispersity index over 1 h, in particular for PDA. Furthermore, cytotoxic effects induced by coated and uncoated GO and rGO on human chondrocytes at different concentrations (12.5, 25, 50 and 100 µg/mL) were assessed through LDH assay. Results showed a concentration-dependent response, and the presence of PGA contributed to statistically decreasing the difference in the LDH activity with respect to the control. These results open the way to a potentially safer use of these nanomaterials in the fields of cartilage tissue engineering and regenerative medicine.

Highlights

Graphene-derived materials have received extensive attention for their exceptional mechanical, electrical, thermal, and optical properties; drug-loading capacity; high surface area-to-volume ratio; and unique atomic and molecular structure [1,2]
We investigated the dispersion of graphene oxide (GO) and reduced GO (rGO) in water by exploring three different types of dispersants, namely glycol chitosan (GC), propylene glycol alginate (PGA), and polydopamine (PDA)
Dispersion, physicochemical characterization, and cytocompatibility evaluation of GO and rGO flakes on human chondrocytes

Summary

Introduction

Graphene-derived materials have received extensive attention for their exceptional mechanical, electrical, thermal, and optical properties; drug-loading capacity; high surface area-to-volume ratio; and unique atomic and molecular structure [1,2]. Both materials are generally featured by a nanometric thickness and a large lateral dimension, from hundreds of nanometers up to tens of microns, making them versatile for several applications. GO and rGO have been used as electrical dopant agents in conductive composite materials [5,6], for mechanical reinforcement of polymeric matrices [7], or as lubricant agents to improve the wear of scaffolds to be used as substitutes for load-bearing joints [8,9]

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