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LETTER TO THE EDITOR Potential of graphene for tissue engineering applications
Q1
To Editor, We read with great interest the article published by Empson et al.1 The authors suggested the use of nanocarbon particles as graphene to replace damaged connective tissues.1 In fact, nanocarbons including carbon nanotubes, carbon nanohorns, and graphenes have also shown an enhancement of matrix mechanical properties; their small size and functional capabilities make them attractive therapeutic options as nanofillers for many regenerative medicine applications. In our recent study,2 we evaluated the effects of the novel biomaterials graphene oxide (GO) and silk fibroin composites on human periodontal ligament mesenchymal stem cells (PDLSCs) phenotype, adhesion, proliferation rate, and viability. Biocompatibility of scaffolds is a prerequisite for generating cell-biomaterial constructs and for their successful clinical application. GO and fibroin-based biomaterials have been previously studied for several tissue engineering based-therapies, but they have never been tested in conjunction with PDLSCs. Morphologic studies by staining of actin cytoskeleton of PDLSCs cultured for different times on GO and fibroin-coated surfaces showed that PDLSCs cultured on fibroin films displayed lower F-actin polymerization, lower cell spreading, and delayed initial adhesion to the biomaterial. By contrast, GO or GO plus fibroin-coated surfaces significantly improved F-actin polymerization, cell spreading, and initial adhesion when compared with fibroin alone. Furthermore, the proliferation rate and phenotype of PDLSCs on GO and fibroin-based biomaterials by MTT colorimetric assays and flow cytometry, respectively, were studied. Reprint requests: Francisco J. Rodrıguez-Lozano, Servicio de Hematologıa y Hemoterapia, Unidad de Trasplante Hematopoyetico y Terapia Celular, Hospital Clınico Universitario Virgen de la Arrixaca, Ctra. Madrid-Cartagena, El Palmar, 30120 Murcia, Spain; e-mail: [email protected] Submitted for publication February 18, 2015; revision submitted March 24, 2015; accepted for publication April 3, 2015. Translational Research 2015;-:1–2. 1931-5244/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.trsl.2015.04.003
Results confirmed that after 7 days of culture, PDLSCs showed a high cell proliferation rate in the presence of GO and GO plus fibroin-coated surfaces compared with fibroin alone, as well as an unaffected expression of the mesenchymal stem cell markers CD73, CD90, and CD105. A remarkable aspect of these carbon biomaterials is that the chemical nature of graphene seems to act on the differentiation of stem cells, raising the possibility of favoring this process by modifying the chemical configuration of these materials. This evidence gives graphene materials a considerable potential to use them as a component in tissue engineering scaffolds.3 It has been already studied the capacity of graphene substrates in the induction of the differentiation of human mesenchymal stem cells into adipocytes,4,5 neural stem cells into neurons in 3-dimensional porous structures,6 and also induced pluripotent stem cells into cells derived from endodermal lineage.7 Furthermore, several adult tissues such as bone marrow stroma and dental tissues contain a variety of mesenchymal stem cells that possess immunosuppressive properties and the ability to differentiate into adipogenic, osteogenic, and chondrogenic cells.8 The aim of periodontal tissue engineering and its application in regenerative medicine is the development of functional tissues or organs combined with biologically active molecules for the treatment of oral and maxillofacial pathologies.9 Therefore, it is important not only to generate hard and soft tissues for periodontal regeneration, but also to achieve the attachment of both tissues. Cellbased tissue engineering requires a cell component from the appropriate origin that could be able to repair the target organ and also a biocompatible material that provides a 3-dimensional scaffold for the chosen cells. The optimal cellularized scaffolds may be those that allow regenerating new tissues with the appropriate structure and function, and also that could provide the appropriate bioactive factors.10,11 The ideal combination of cell and scaffold sources varies in relation to the target tissue to be created. Moreover, there have been recent advances in biomaterial synthesis and fabrication tools resulting in the creation of functional and bioactive 1
COR 5.2.0 DTD TRSL895_proof 28 April 2015 9:39 am ce
Q2
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Translational Research - 2015
Rodrıguez-Lozano et al
scaffolds that stimulate different cell functions.12 So, we considered that graphene could be a suitable scaffold for periodontal tissue regeneration. However, additional in vitro and in vivo studies are needed to elucidate the full mechanisms of action of the actual available configurations of graphene-based scaffolds and to convert this carbon material in a promising field of extensive research to find new scaffolds for tissue engineering. ACKNOWLEDGMENTS
Conflicts of Interest: All authors have read the journals policy on disclosure of potential conflicts of interest and have none to declare. This work was supported by FIS EC07/90762 grant and the Spanish Net of Cell Therapy (TerCel) provided by the Carlos III Institute of Health (ISCiii) (PI13/02699 and EC11-009) together with the Junction Program for Biomedical Research in Advanced Therapies and Regenerative Medicine from ISCiii. All authors have read the journals authorship agreement. Q3
Francisco J. Rodrıguez-Lozanoa,* David Garcıa-Bernala Salvador Aznar-Cervantesb Ricardo E. O~nate-Sancheza Jose M. Moraledaa a Cell Therapy Unit, Virgen de la Arrixaca Clinical University Hospital IMIB-Arrixaca University of Murcia Murcia, Spain b Department of Biotechnology Instituto Murciano de Investigaci on y Desarrollo Agrario y Alimentario (IMIDA) Murcia, Spain
REFERENCES
1. Empson YM, Ekwueme EC, Hong JK, et al. High elastic modulus nanoparticles: a novel tool for subfailure connective tissue matrix damage. Transl Res 2014;164:244–57. 2. Rodrıguez-Lozano FJ, Garcıa-Bernal D, Aznar-Cervantes S, et al. Effects of composite films of silk fibroin and graphene oxide on the proliferation, cell viability and mesenchymal phenotype of periodontal ligament stem cells. J Mater Sci Mater Med 2014;25: 2731–41. 3. Bressan E, Ferroni L, Gardin C, et al. Graphene based scaffolds effects on stem cells commitment. J Transl Med 2014;12:296. 4. Lee WC, Lim CH, Shi H, et al. Origin of enhanced stem cell growth and differentiation on graphene and graphene oxide. ACS Nano 2011;5:7334–41. 5. Ku SH, Park CB. Myoblast differentiation on graphene oxide. Biomaterials 2013;34:2017–23. 6. Park SY, Park J, Sim SH, et al. Enhanced differentiation of human neural stem cells into neurons on graphene. Adv Mater 2011;23: H263–7. 7. Chen GY, Pang DW, Hwang SM, et al. A graphene-based platform for induced pluripotent stem cells culture and differentiation. Biomaterials 2012;33:418–27. 8. Rodrıguez-Lozano FJ, Moraleda JM. Use of dental stem cells in regenerative dentistry: a possible alternative. Transl Res 2011; 158:385–6. 9. Baptista PM, Atala A. Regenerative medicine: the hurdles and hopes. Transl Res 2014;163:255–8. 10. Levenberg S, Langer R. Advances in tissue engineering. Curr Top Dev Biol 2004;61:113–34. 11. Sasikumar KP, Elavarasu S, Gadagi JS. The application of bone morphogenetic proteins to periodontal and peri-implant tissue regeneration: a literature review. J Pharm Bioallied Sci 2012; 4(suppl 2):S427–30. 12. Jin G, Li K. The electrically conductive scaffold as the skeleton of stem cell niche in regenerative medicine. Mater Sci Eng C Mater Biol Appl 2014;45:671–81.
COR 5.2.0 DTD TRSL895_proof 28 April 2015 9:39 am ce
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LETTER TO THE EDITOR Potential of graphene for tissue engineering applications
Q1
To Editor, We read with great interest the article published by Empson et al.1 The authors suggested the use of nanocarbon particles as graphene to replace damaged connective tissues.1 In fact, nanocarbons including carbon nanotubes, carbon nanohorns, and graphenes have also shown an enhancement of matrix mechanical properties; their small size and functional capabilities make them attractive therapeutic options as nanofillers for many regenerative medicine applications. In our recent study,2 we evaluated the effects of the novel biomaterials graphene oxide (GO) and silk fibroin composites on human periodontal ligament mesenchymal stem cells (PDLSCs) phenotype, adhesion, proliferation rate, and viability. Biocompatibility of scaffolds is a prerequisite for generating cell-biomaterial constructs and for their successful clinical application. GO and fibroin-based biomaterials have been previously studied for several tissue engineering based-therapies, but they have never been tested in conjunction with PDLSCs. Morphologic studies by staining of actin cytoskeleton of PDLSCs cultured for different times on GO and fibroin-coated surfaces showed that PDLSCs cultured on fibroin films displayed lower F-actin polymerization, lower cell spreading, and delayed initial adhesion to the biomaterial. By contrast, GO or GO plus fibroin-coated surfaces significantly improved F-actin polymerization, cell spreading, and initial adhesion when compared with fibroin alone. Furthermore, the proliferation rate and phenotype of PDLSCs on GO and fibroin-based biomaterials by MTT colorimetric assays and flow cytometry, respectively, were studied. Reprint requests: Francisco J. Rodrıguez-Lozano, Servicio de Hematologıa y Hemoterapia, Unidad de Trasplante Hematopoyetico y Terapia Celular, Hospital Clınico Universitario Virgen de la Arrixaca, Ctra. Madrid-Cartagena, El Palmar, 30120 Murcia, Spain; e-mail: [email protected] Submitted for publication February 18, 2015; revision submitted March 24, 2015; accepted for publication April 3, 2015. Translational Research 2015;-:1–2. 1931-5244/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.trsl.2015.04.003
Results confirmed that after 7 days of culture, PDLSCs showed a high cell proliferation rate in the presence of GO and GO plus fibroin-coated surfaces compared with fibroin alone, as well as an unaffected expression of the mesenchymal stem cell markers CD73, CD90, and CD105. A remarkable aspect of these carbon biomaterials is that the chemical nature of graphene seems to act on the differentiation of stem cells, raising the possibility of favoring this process by modifying the chemical configuration of these materials. This evidence gives graphene materials a considerable potential to use them as a component in tissue engineering scaffolds.3 It has been already studied the capacity of graphene substrates in the induction of the differentiation of human mesenchymal stem cells into adipocytes,4,5 neural stem cells into neurons in 3-dimensional porous structures,6 and also induced pluripotent stem cells into cells derived from endodermal lineage.7 Furthermore, several adult tissues such as bone marrow stroma and dental tissues contain a variety of mesenchymal stem cells that possess immunosuppressive properties and the ability to differentiate into adipogenic, osteogenic, and chondrogenic cells.8 The aim of periodontal tissue engineering and its application in regenerative medicine is the development of functional tissues or organs combined with biologically active molecules for the treatment of oral and maxillofacial pathologies.9 Therefore, it is important not only to generate hard and soft tissues for periodontal regeneration, but also to achieve the attachment of both tissues. Cellbased tissue engineering requires a cell component from the appropriate origin that could be able to repair the target organ and also a biocompatible material that provides a 3-dimensional scaffold for the chosen cells. The optimal cellularized scaffolds may be those that allow regenerating new tissues with the appropriate structure and function, and also that could provide the appropriate bioactive factors.10,11 The ideal combination of cell and scaffold sources varies in relation to the target tissue to be created. Moreover, there have been recent advances in biomaterial synthesis and fabrication tools resulting in the creation of functional and bioactive 1
COR 5.2.0 DTD TRSL895_proof 28 April 2015 9:39 am ce
Q2
53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104
2
105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158
Translational Research - 2015
Rodrıguez-Lozano et al
scaffolds that stimulate different cell functions.12 So, we considered that graphene could be a suitable scaffold for periodontal tissue regeneration. However, additional in vitro and in vivo studies are needed to elucidate the full mechanisms of action of the actual available configurations of graphene-based scaffolds and to convert this carbon material in a promising field of extensive research to find new scaffolds for tissue engineering. ACKNOWLEDGMENTS
Conflicts of Interest: All authors have read the journals policy on disclosure of potential conflicts of interest and have none to declare. This work was supported by FIS EC07/90762 grant and the Spanish Net of Cell Therapy (TerCel) provided by the Carlos III Institute of Health (ISCiii) (PI13/02699 and EC11-009) together with the Junction Program for Biomedical Research in Advanced Therapies and Regenerative Medicine from ISCiii. All authors have read the journals authorship agreement. Q3
Francisco J. Rodrıguez-Lozanoa,* David Garcıa-Bernala Salvador Aznar-Cervantesb Ricardo E. O~nate-Sancheza Jose M. Moraledaa a Cell Therapy Unit, Virgen de la Arrixaca Clinical University Hospital IMIB-Arrixaca University of Murcia Murcia, Spain b Department of Biotechnology Instituto Murciano de Investigaci on y Desarrollo Agrario y Alimentario (IMIDA) Murcia, Spain
REFERENCES
1. Empson YM, Ekwueme EC, Hong JK, et al. High elastic modulus nanoparticles: a novel tool for subfailure connective tissue matrix damage. Transl Res 2014;164:244–57. 2. Rodrıguez-Lozano FJ, Garcıa-Bernal D, Aznar-Cervantes S, et al. Effects of composite films of silk fibroin and graphene oxide on the proliferation, cell viability and mesenchymal phenotype of periodontal ligament stem cells. J Mater Sci Mater Med 2014;25: 2731–41. 3. Bressan E, Ferroni L, Gardin C, et al. Graphene based scaffolds effects on stem cells commitment. J Transl Med 2014;12:296. 4. Lee WC, Lim CH, Shi H, et al. Origin of enhanced stem cell growth and differentiation on graphene and graphene oxide. ACS Nano 2011;5:7334–41. 5. Ku SH, Park CB. Myoblast differentiation on graphene oxide. Biomaterials 2013;34:2017–23. 6. Park SY, Park J, Sim SH, et al. Enhanced differentiation of human neural stem cells into neurons on graphene. Adv Mater 2011;23: H263–7. 7. Chen GY, Pang DW, Hwang SM, et al. A graphene-based platform for induced pluripotent stem cells culture and differentiation. Biomaterials 2012;33:418–27. 8. Rodrıguez-Lozano FJ, Moraleda JM. Use of dental stem cells in regenerative dentistry: a possible alternative. Transl Res 2011; 158:385–6. 9. Baptista PM, Atala A. Regenerative medicine: the hurdles and hopes. Transl Res 2014;163:255–8. 10. Levenberg S, Langer R. Advances in tissue engineering. Curr Top Dev Biol 2004;61:113–34. 11. Sasikumar KP, Elavarasu S, Gadagi JS. The application of bone morphogenetic proteins to periodontal and peri-implant tissue regeneration: a literature review. J Pharm Bioallied Sci 2012; 4(suppl 2):S427–30. 12. Jin G, Li K. The electrically conductive scaffold as the skeleton of stem cell niche in regenerative medicine. Mater Sci Eng C Mater Biol Appl 2014;45:671–81.
COR 5.2.0 DTD TRSL895_proof 28 April 2015 9:39 am ce
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