1
|
Näf L, Miescher I, Pfuderer L, Schweizer TA, Brunner D, Dürig J, Gröninger O, Rieber J, Meier-Buergisser G, Spanaus K, Calcagni M, Bosshard PP, Achermann Y, Stark WJ, Buschmann J. Pro-angiogenic and antibacterial copper containing nanoparticles in PLGA/amorphous calcium phosphate bone nanocomposites. Heliyon 2024; 10:e27267. [PMID: 38486752 PMCID: PMC10937708 DOI: 10.1016/j.heliyon.2024.e27267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
Large bone defects after trauma demand for adequate bone substitutes. Bone void fillers should be antibacterial and pro-angiogenic. One viable option is the use of composite materials like the combination of PLGA and amorphous calcium phosphate (aCaP). Copper stimulates angiogenesis and has antibacterial qualities. Either copper oxide (CuO) nanoparticles (NPs) were therefore added to PLGA/aCaP/CuO in different concentrations (1, 5 and 10 w/w %) or copper-doped tricalcium phosphate NPs (TCP with 2% of copper) were electrospun into PLGA/CuTCP nanocomposites. Bi-layered nanocomposites of PLGA/aCaP with different copper NPs (CuO or TCP) and a second layer of pristine PLGA were fabricated. Two clinical bacterial isolates (Staphylococcus aureus and Staphylococcus epidermidis) were used to assess antibacterial properties of the copper-containing materials. For angiogenesis, the chorioallantoic membrane (CAM) assay of the chicken embryo was performed. The higher the CuO content, the higher were the antibacterial properties, with 10 % CuO reducing bacterial adhesion most effectively. Vessel and cell densities were highest in the 5 % CuO containing scaffolds, while tissue integration was more pronounced at lower CuO content. The PLGA/aCaP/CuO (1 % CuO) behaved similar like PLGA/CuTCP in all angiogenic and antibacterial readouts, based on the same copper fraction. We conclude that CuO NPs or CuTCP NPs are useful components to increase angiogenic properties of nanocomposites and at the same time exhibiting antibacterial characteristics.
Collapse
Affiliation(s)
- Lukas Näf
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Iris Miescher
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Lara Pfuderer
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Tiziano A. Schweizer
- Department of Dermatology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - David Brunner
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Johannes Dürig
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Olivier Gröninger
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Julia Rieber
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Gabriella Meier-Buergisser
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Katharina Spanaus
- Clinical Chemistry, University Hospital Zurich, 8001, Zurich, Switzerland
| | - Maurizio Calcagni
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| | - Philipp P. Bosshard
- Department of Dermatology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - Yvonne Achermann
- Department of Dermatology, University Hospital Zurich, University of Zurich, Rämistrasse 100, 8091, Zurich, Switzerland
| | - Wendelin J. Stark
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Johanna Buschmann
- Department of Plastic Surgery and Hand Surgery, University Hospital of Zürich, Rämistrasse 100, 8091, Zürich, Switzerland
| |
Collapse
|
2
|
Hybrid nanocomposite as a chest wall graft with improved vascularization by copper oxide nanoparticles. J Biomater Appl 2022; 36:1826-1837. [DOI: 10.1177/08853282211065624] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Chest wall repair can be necessary after tumor resection or chest injury. In order to cover or replace chest wall defects, autologous tissue or different synthetic materials are commonly used, among them the semi-rigid gold standard Gore-Tex® and prolene meshes. Synthetic tissues include composite materials with an organic and an inorganic component. On the basis of previously reported hybrid nanocomposite poly-lactic-co-glycolic acid amorphous calcium phosphate nanocomposite (PLGA/aCaP), a CuO component was incorporated to yield (60%/35%/5%). This graft was tested in vitro by seeding with murine adipose-derived stem cells (ASCs) for cell attachment and migration. The graft was compared to PLGA/CaCO3 and PLGA/hydroxyapatite, each providing the inorganic phase as nanoparticles. Further characterization of the graft was performed using scanning electron microscopy. Furthermore, PLGA/aCaP/CuO was implanted as a chest wall graft in mice. After 4 weeks, total cell density, graft integration, extracellular matrix components such as fibronectin and collagen I, the cellular inflammatory response (macrophages, F4/80 and lymphocytes, CD3) as well as vascularization (CD31) were quantitatively assessed. The nanocomposite PLGA/aCaP/CuO showed a good cell attachment and cells migrated well into the pores of the electrospun meshes. Cell densities did not differ between PLGA/aCaP/CuO and PLGA/CaCO3 or PLGA/hydroxyapatite, respectively. When applied as a chest wall graft, adequate stability for suturing into the thoracic wall could be achieved. Four weeks post-implantation, there was an excellent tissue integration without relevant fibrotic changes and a predominating collagen I matrix deposition within the graft. Slightly increased inflammation, reflected by increased infiltration of macrophages could be observed. Vascularization of the graft was significantly enhanced when compared with PLGA/aCaP (no CuO). We conclude that the hybrid nanocomposite PLGA/aCaP/CuO is a viable option to be used as a chest wall graft. Surgical implantation of the material is feasible and provides stability and enough flexibility. Proper tissue integration and an excellent vascularization are characteristics of this biodegradable material.
Collapse
|
3
|
Kamat P, Frueh FS, McLuckie M, Sanchez-Macedo N, Wolint P, Lindenblatt N, Plock JA, Calcagni M, Buschmann J. Adipose tissue and the vascularization of biomaterials: Stem cells, microvascular fragments and nanofat-a review. Cytotherapy 2020; 22:400-411. [PMID: 32507607 DOI: 10.1016/j.jcyt.2020.03.433] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/27/2020] [Accepted: 03/12/2020] [Indexed: 12/13/2022]
Abstract
Tissue defects in the human body after trauma and injury require precise reconstruction to regain function. Hence, there is a great demand for clinically translatable approaches with materials that are both biocompatible and biodegradable. They should also be able to adequately integrate within the tissue through sufficient vascularization. Adipose tissue is abundant and easily accessible. It is a valuable tissue source in regenerative medicine and tissue engineering, especially with regard to its angiogenic potential. Derivatives of adipose tissue, such as microfat, nanofat, microvascular fragments, stromal vascular fraction and stem cells, are commonly used in research, but also clinically to enhance the vascularization of implants and grafts at defect sites. In plastic surgery, adipose tissue is harvested via liposuction and can be manipulated in three ways (macro-, micro- and nanofat) in the operating room, depending on its ultimate use. Whereas macro- and microfat are used as a filling material for soft tissue injuries, nanofat is an injectable viscous extract that primarily induces tissue remodeling because it is rich in growth factors and stem cells. In contrast to microfat that adds volume to a defect site, nanofat has the potential to be easily combined with scaffold materials due to its liquid and homogenous consistency and is particularly attractive for blood vessel formation. The same is true for microvascular fragments that are easily isolated from adipose tissue through collagenase digestion. In preclinical animal models, it has been convincingly shown that these vascular fragments inosculate with host vessels and subsequently accelerate scaffold perfusion and host tissue integration. Adipose tissue is also an ideal source of stem cells. It yields larger quantities of cells than any other source and is easier to access for both the patient and doctor compared with other sources such as bone marrow. They are often used for tissue regeneration in combination with biomaterials. Adipose-derived stem cells can be applied unmodified or as single cell suspensions. However, certain pretreatments, such as cultivation under hypoxic conditions or three-dimensional spheroids production, may provide substantial benefit with regard to subsequent vascularization in vivo due to induced growth factor production. In this narrative review, derivatives of adipose tissue and the vascularization of biomaterials are addressed in a comprehensive approach, including several sizes of derivatives, such as whole fat flaps for soft tissue engineering, nanofat or stem cells, their secretome and exosomes. Taken together, it can be concluded that adipose tissue and its fractions down to the molecular level promote, enhance and support vascularization of biomaterials. Therefore, there is a high potential of the individual fat component to be used in regenerative medicine.
Collapse
Affiliation(s)
- Pranitha Kamat
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland; Department of Plastic Surgery and Hand Surgery, University of Zurich, Zurich, Switzerland
| | - Florian S Frueh
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Michelle McLuckie
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Nadia Sanchez-Macedo
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Petra Wolint
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Nicole Lindenblatt
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Jan A Plock
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland; Department of Plastic Surgery and Hand Surgery, University of Zurich, Zurich, Switzerland
| | - Maurizio Calcagni
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Johanna Buschmann
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland.
| |
Collapse
|
4
|
Schneider I, Baumgartner W, Gröninger O, Stark WJ, Märsmann S, Calcagni M, Cinelli P, Wolint P, Buschmann J. 3D microtissue-derived human stem cells seeded on electrospun nanocomposites under shear stress: Modulation of gene expression. J Mech Behav Biomed Mater 2019; 102:103481. [PMID: 31678737 DOI: 10.1016/j.jmbbm.2019.103481] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/17/2019] [Accepted: 10/08/2019] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Different microenvironments trigger distinct differentiation of stem cells. Even without chemical supplementation, mechanical stimulation by shear stress may help to induce the desired differentiation. The cell format, such as three-dimensional (3D) microtissues (MTs), MT-derived cells or single cells (SCs), may have a pivotal impact as well. Here, we studied modulation of gene expression in human adipose-derived stem cells (ASCs) exposed to shear stress and/or after MT formation. MATERIALS AND METHODS Electrospun meshes of poly-lactic-co-glycolic acid and amorphous calcium phosphate nanoparticles (PLGA/aCaP) at a weight ratio of 60:40 were seeded with human ASCs as MTs or as SCs and cultured in Dulbecco's modified Eagle's medium without chemical supplementation. After 2 weeks of static culture, the scaffolds were cultured statically for another 2 weeks or placed in a Bose® bioreactor with a flow rate per area of 0.16 mL cm-2 min-1. Stiffness of the scaffolds was assessed as a function of time. After 4 weeks, minimum stem cell criteria markers and selected markers of osteogenesis, endothelial cell differentiation, adipogenesis and chondrogenesis were analysed by quantitative real-time polymerase chain reaction. Additionally, cell distribution within the scaffolds and the allocation of the yes-associated protein (YAP) in the cells were assessed by immunohistochemistry. RESULTS MTs decayed completely within 2 weeks after seeding on PLGA/aCaP. The osteogenic marker gene alkaline phosphatase and the endothelial cell marker gene CD31 were upregulated in MT-derived ASCs compared with SCs. Shear stress realised by fluid flow perfusion upregulated peroxisome proliferator-activated receptor gamma 2 expression in MT-derived ASCs and in SCs. The nuclear-to-cytoplasmic ratio of YAP expression was doubled under perfusion compared with that under static culture for MT-derived ASCs and SCs. CONCLUSIONS Osteogenic and angiogenic commitments were more pronounced in MT-derived ASCs seeded on bone biomimetic electrospun nanocomposite PLGA/aCaP than in SCs seeded without induction medium. Furthermore, the static culture was superior to the perfusion regimen used here, as shear stress resulted in adipogenic commitment for MT-derived ASCs and SCs, although the YAP nuclear-to-cytoplasmic ratio indicated higher cell tensions under perfusion, usually associated with preferred osteogenic differentiation.
Collapse
Affiliation(s)
- Isabelle Schneider
- Division of Plastic and Hand Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland
| | - Walter Baumgartner
- Division of Plastic and Hand Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland
| | - Olivier Gröninger
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Wendelin J Stark
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Sonja Märsmann
- Division of Plastic and Hand Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland; Division of Trauma Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland
| | - Maurizio Calcagni
- Division of Plastic and Hand Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland
| | - Paolo Cinelli
- Division of Trauma Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland
| | - Petra Wolint
- Division of Plastic and Hand Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland
| | - Johanna Buschmann
- Division of Plastic and Hand Surgery, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland.
| |
Collapse
|
5
|
Buschmann J, Yamada Y, Schulz-Schönhagen K, Hess SC, Stark WJ, Opelz C, Bürgisser GM, Weder W, Jungraithmayr W. Hybrid nanocomposite as a chest wall graft with improved integration by adipose-derived stem cells. Sci Rep 2019; 9:10910. [PMID: 31358841 PMCID: PMC6662805 DOI: 10.1038/s41598-019-47441-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 07/15/2019] [Indexed: 02/07/2023] Open
Abstract
Surgery of the chest wall is potentially required to cover large defects after removal of malignant tumours. Usually, inert and non-degradable Gore-Tex serves to replace the missing tissue. However, novel biodegradable materials combined with stem cells are available that stimulate the healing. Based on poly-lactic-co-glycolic acid and amorphous calcium phosphate nanoparticles (PLGA/aCaP) and pure PLGA, a dual layer biodegradable hybrid nanocomposite was generated. Mouse adipose-derived stem cells were cultered on electrospun disks (ASCs of C57BL/6), and biomechanical tests were performed. The cell-seeded scaffolds were engrafted in C57BL/LY5.1 mice to serve as a chest wall substitute. Cell invasion into the bi-layered material, extent of CD45+ cells, inflammatory response, neo-vascularization and ECM composition were determined at 1 and 2 months post-surgery, respectively. The bi-layered hybrid nanocomposite was stable after a 2-week in vitro culture, in contrast to PLGA/aCaP without a PLGA layer. There was a complete biointegration and good vascularization in vivo. The presence of ASCs attracted more CD45+ cells (hematopoietic origin) compared to cell-free scaffolds. Inflammatory reaction was similar for both groups (±ASCs) at 8 weeks. A bi-layered hybrid nanocomposite fabricated of electrospun PLGA/aCaP and a reinforcing layer of pristine PLGA is an ideal scaffold for chest wall reconstruction. It is stable and allows a proper host tissue integration. If ASCs are seeded, they attract more CD45+ cells, supporting the regeneration process.
Collapse
Affiliation(s)
- Johanna Buschmann
- Division of Plastic and Hand Surgery, University Hospital Zurich, Zurich, Switzerland.
| | - Yoshito Yamada
- Department of Thoracic Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Konstantin Schulz-Schönhagen
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Samuel C Hess
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Wendelin J Stark
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Christine Opelz
- Department of Thoracic Surgery, University Hospital Zurich, Zurich, Switzerland
| | | | - Walter Weder
- Department of Thoracic Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Wolfgang Jungraithmayr
- Department of Thoracic Surgery, University Hospital Zurich, Zurich, Switzerland.,Department of Thoracic Surgery, University Hospital Rostock, Rostock, Germany
| |
Collapse
|
6
|
Buschmann J, Balli E, Hess SC, Stark WJ, Cinelli P, Märsmann S, Welti M, Weder W, Jungraithmayr W. Effects of seeding adipose-derived stem cells on electrospun nanocomposite used as chest wall graft in a murine model. Injury 2017; 48:2080-2088. [PMID: 28842288 DOI: 10.1016/j.injury.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 08/02/2017] [Indexed: 02/02/2023]
Abstract
Malignant neoplasms infiltrating the chest wall often requires resection of the thoracic wall. To replace the defect, Gore-Tex® is usually employed as the gold standard material, however, Gore-Tex® is inert and not degradable. Novel materials are nowadays available which allow a full bio-integration due to their non-toxic degradability. Additionally, stem cell seeding has the capacity to reduce inflammatory response towards such grafts, thus integrating it better into the host organism.
Collapse
Affiliation(s)
- Johanna Buschmann
- Division of Plastic and Hand Surgery, University Hospital Zurich, Switzerland.
| | - Eleni Balli
- Division of Plastic and Hand Surgery, University Hospital Zurich, Switzerland
| | - Samuel C Hess
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Wendelin J Stark
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Paolo Cinelli
- Division of Trauma Surgery, University Hospital Zurich, Switzerland
| | - Sonja Märsmann
- Division of Plastic and Hand Surgery, University Hospital Zurich, Switzerland; Division of Trauma Surgery, University Hospital Zurich, Switzerland
| | - Manfred Welti
- Division of Plastic and Hand Surgery, University Hospital Zurich, Switzerland; Division of Thoracic Surgery, University Hospital Zurich, Switzerland
| | - Walter Weder
- Division of Thoracic Surgery, University Hospital Zurich, Switzerland
| | | |
Collapse
|
7
|
Woloszyk A, Liccardo D, Mitsiadis TA. Three-Dimensional Imaging of the Developing Vasculature within Stem Cell-Seeded Scaffolds Cultured in ovo. Front Physiol 2016; 7:146. [PMID: 27148081 PMCID: PMC4838783 DOI: 10.3389/fphys.2016.00146] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/04/2016] [Indexed: 11/16/2022] Open
Abstract
Successful tissue engineering requires functional vascularization of the three-dimensional constructs with the aim to serve as implants for tissue replacement and regeneration. The survival of the implant is only possible if the supply of oxygen and nutrients by developing capillaries from the host is established. The chorioallantoic membrane (CAM) assay is a valuable tool to study the ingrowth and distribution of vessels into scaffolds composed by appropriate biomaterials and stem cell populations that are used in cell-based regenerative approaches. The developing vasculature of chicken embryos within cell-seeded scaffolds can be visualized with microcomputed tomography after intravenous injection of MicroFil®, which is a radiopaque contrast agent. Here, we provide a step-by-step protocol for the seeding of stem cells into silk fibroin scaffolds, the CAM culture conditions, the procedure of MicroFil® perfusion, and finally the microcomputed tomography scanning. Three-dimensional imaging of the vascularized tissue engineered constructs provides an important analytical tool for studying the potential of cell seeded scaffolds to attract vessels and form vascular networks, as well as for analyzing the number, density, length, branching, and diameter of vessels. This in ovo method can greatly help to screen implants that will be used for tissue regeneration purposes before their in vivo testing, thereby reducing the amount of animals needed for pre-clinical studies.
Collapse
Affiliation(s)
- Anna Woloszyk
- Orofacial Development and Regeneration, Centre for Dental Medicine, Institute of Oral Biology, University of Zurich Zurich, Switzerland
| | - Davide Liccardo
- Section of Biotechnology and Medical Histology and Embryology, Department of Experimental Medicine, Second University of Naples Naples, Italy
| | - Thimios A Mitsiadis
- Orofacial Development and Regeneration, Centre for Dental Medicine, Institute of Oral Biology, University of Zurich Zurich, Switzerland
| |
Collapse
|
8
|
Liu J, Schmidlin PR, Philipp A, Hild N, Tawse-Smith A, Duncan W. Novel bone substitute material in alveolar bone healing following tooth extraction: an experimental study in sheep. Clin Oral Implants Res 2015; 27:762-70. [DOI: 10.1111/clr.12673] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Jinyi Liu
- Private Periodontal Practice; Auckland New Zealand
| | - Patrick R. Schmidlin
- Clinic of Preventive Dentistry, Periodontology and Cariology; University of Zürich; Zürich Switzerland
| | - Alexander Philipp
- Clinic of Preventive Dentistry, Periodontology and Cariology; University of Zürich; Zürich Switzerland
| | - Nora Hild
- Institute for Chemical and Bioengineering; ETH Zurich; Zurich Switzerland
| | | | - Warwick Duncan
- Department of Oral Sciences; University of Otago; Dunedin New Zealand
| |
Collapse
|
9
|
Baumgartner W, Welti M, Hild N, Hess SC, Stark WJ, Bürgisser GM, Giovanoli P, Buschmann J. Tissue mechanics of piled critical size biomimetic and biominerizable nanocomposites: Formation of bioreactor-induced stem cell gradients under perfusion and compression. J Mech Behav Biomed Mater 2015; 47:124-134. [DOI: 10.1016/j.jmbbm.2015.03.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/18/2015] [Accepted: 03/24/2015] [Indexed: 02/08/2023]
|
10
|
Kamel M, Port J, Altorki NK. Sternal Resections: New Materials for Reconstruction. CURRENT SURGERY REPORTS 2015. [DOI: 10.1007/s40137-015-0094-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
11
|
Georgiopoulos P, Kontou E, Meristoudi A, Pispas S, Chatzinikolaidou M. Τhe effect of silica nanoparticles on the thermomechanical properties and degradation behavior of polylactic acid. J Biomater Appl 2014; 29:662-74. [PMID: 25091863 DOI: 10.1177/0885328214545351] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In this work a series of polylactic acid/SiO2 nanocomposites have been prepared by a melt mixing procedure. The dispersion quality was examined by scanning electron microscopy. To study the degradation behavior of the polylactic acid/nanocomposites prepared, the samples were immersed in a buffer solution at a temperature of 37℃ with a pH of 7.4 for a time period of up to 23 weeks. These conditions simulate those in the human body, appropriate in medical applications. In order to assess their suitability in biomedical applications, we investigated the biocompatibility of these materials in terms of cell viability, growth, and morphology. A good initial cell adhesion has been detected, supporting their potential use in bone tissue engineering applications. The hydrolytic degradation of polylactic acid, under the prescribed conditions, was studied by the molecular weight reduction in terms of size exclusion chromatography, whereas the progress of thermal stability of polylactic acid and polylactic acid/nanocomposites during aging was tested by thermogravimetric analysis. The evolution of the materials' thermomechanical properties during aging was studied by differential scanning calorimetry, dynamic mechanical analysis, and tensile testing. The crystallization behavior in polylactic acid and the way it is affected by the presence of nanofillers during degradation procedure has been studied and values of 44% crystallinity increment have been found. At the specific aging conditions studied, silica nanoparticles accelerate the degradability of polylactic acid, having a higher impact on Young's modulus, under the specified aging conditions, for 7 weeks and hereafter this acceleration is retarded, due to the crystallinity increment, as a result of the molecular weight reduction.
Collapse
Affiliation(s)
- P Georgiopoulos
- School of Applied Mathematical and Physical Sciences, Department of Mechanics, National Technical University of Athens, Athens, Greece
| | - E Kontou
- School of Applied Mathematical and Physical Sciences, Department of Mechanics, National Technical University of Athens, Athens, Greece
| | - A Meristoudi
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens, Greece
| | - S Pispas
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens, Greece
| | - M Chatzinikolaidou
- Department of Materials Science and Technology, University of Crete, Heraklio, Greece Institute of Electronic Structure & Laser, Foundation for Research & Technology Hellas, Heraklio, Greece
| |
Collapse
|