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Publications (9 of 9) Show all publications
Flys, O., Jarlemark, P., Petronis, S., Stenlund, P. & Rosen, B.-G. -. (2018). Applicability of characterization techniques on fine scale surfaces. Surface Topography: Metrology and Properties, 6(3), Article ID 034015.
Open this publication in new window or tab >>Applicability of characterization techniques on fine scale surfaces
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2018 (English)In: Surface Topography: Metrology and Properties, ISSN 2051-672X, Vol. 6, no 3, article id 034015Article in journal (Refereed) Published
Abstract [en]

In this study, several surface topographies typical for dental implants were evaluated by different measurement techniques. The samples were prepared by machine turning, wet chemical etching and electrochemical polishing of titanium discs. The measurement techniques included an atomic force microscope (AFM), coherence scanning interferometer (CSI) and a 3D stereo scanning electron microscope (SEM). The aim was to demonstrate and discuss similarities and differences in the results provided by these techniques when analyzing submicron surface topographies. The estimated surface roughness parameters were not directly comparable since the techniques had different surface spatial wavelength band limits. However, the comparison was made possible by applying a 2D power spectral density (PSD) function. Furthermore, to simplify the comparison, all measurements were characterized using the ISO 25178 standard parameters. Additionally, a Fourier transform was applied to calculate the instrument transfer function in order to investigate the behavior of CSI at different wavelength ranges. The study showed that 3D stereo SEM results agreed well with AFM measurements for the studied surfaces. Analyzed surface parameter values were in general higher when measured by CSI in comparison to both AFM and 3D stereo SEM results. In addition, the PSD analysis showed a higher power spectrum density in the lower frequency range 10-2-10-1 μm-1 for the CSI compared with the other techniques.

Keywords
3D-stereo SEM, AFM, Coherence scanning interferometer, power spectral density, surface topography, transfer function, Atomic force microscopy, Chemical polishing, Dental prostheses, Interferometers, Scanning, Scanning electron microscopy, Spectral density, Surface roughness, Topography, Transfer functions, Wet etching, 3d stereos, Characterization techniques, Measurement techniques, Power spectrum density, Scanning interferometers, Spatial wavelengths, Surface roughness parameters, Wavelength ranges, Parameter estimation
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35683 (URN)10.1088/2051-672X/aacf5e (DOI)2-s2.0-85055559461 (Scopus ID)
Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2018-11-06Bibliographically approved
Granskog, V., García-Gallego, S., von Kieseritzky, J., Rosendahl, J., Stenlund, P., Zhang, Y., . . . Malkoch, M. (2018). High-Performance Thiol–Ene Composites Unveil a New Era of Adhesives Suited for Bone Repair. Advanced Functional Materials, 28(26), Article ID 1800372.
Open this publication in new window or tab >>High-Performance Thiol–Ene Composites Unveil a New Era of Adhesives Suited for Bone Repair
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2018 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, no 26, article id 1800372Article in journal (Refereed) Published
Abstract [en]

The use of adhesives for fracture fixation can revolutionize the surgical procedures toward more personalized bone repairs. However, there are still no commercially available adhesive solutions mainly due to the lack of biocompatibility, poor adhesive strength, or inadequate fixation protocols. Here, a surgically realizable adhesive system capitalizing on visible light thiol–ene coupling chemistry is presented. The adhesives are carefully designed and formulated from a novel class of chemical constituents influenced by dental resin composites and self-etch primers. Validation of the adhesive strength is conducted on wet bone substrates and accomplished via fiber-reinforced adhesive patch (FRAP) methodology. The results unravel, for the first time, on the promise of a thiol–ene adhesive with an unprecedented shear bond strength of 9.0 MPa and that surpasses, by 55%, the commercially available acrylate dental adhesive system Clearfil SE Bond of 5.8 MPa. Preclinical validation of FRAPs on rat femur fracture models details good adhesion to the bone throughout the healing process, and are found biocompatible not giving rise to any inflammatory response. Remarkably, the FRAPs are found to withstand loads up to 70 N for 1000 cycles on porcine metacarpal fractures outperforming clinically used K-wires and match metal plates and screw implants.

Keywords
adhesives, biomedical applications, composites, photochemistry, polymeric materials, Biocompatibility, Composite materials, Dental composites, Dental materials, Fracture, Fracture fixation, Functional polymers, Medical applications, Photochemical reactions, Polymeric implants, Polymers, Chemical constituents, Coupling chemistry, Dental adhesive system, Dental resin composites, Inflammatory response, Shear bond strengths, Surgical procedures, Bone
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33958 (URN)10.1002/adfm.201800372 (DOI)2-s2.0-85048981911 (Scopus ID)
Note

Funding details: KI, Karolinska Institutet; Funding details: MSCA-IF-2014-655649, MSCA, H2020 Marie Skłodowska-Curie Actions; Funding details: 2010-435; Funding details: 2014-03777; Funding details: 2012-0196, Knut och Alice Wallenbergs Stiftelse; 

Available from: 2018-07-03 Created: 2018-07-03 Last updated: 2019-08-19Bibliographically approved
Kuna, V. K., Padma, A. M., Håkansson, J., Nygren, J., Sjöback, R., Petronis, S. & Sumitran-Holgersson, S. (2017). Significantly accelerated wound healing of full-thickness skin using a novel composite gel of porcine acellular dermal matrix and human peripheral blood cells. Cell Transplantation, 26(2), 293-307
Open this publication in new window or tab >>Significantly accelerated wound healing of full-thickness skin using a novel composite gel of porcine acellular dermal matrix and human peripheral blood cells
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2017 (English)In: Cell Transplantation, ISSN 0963-6897, E-ISSN 1555-3892, Vol. 26, no 2, p. 293-307Article in journal (Refereed) Published
Abstract [en]

Herein, we report the fabrication of a novel composite gel from decellularized gal-gal-knockout porcine skin and human peripheral blood mononuclear cells (hPBMC) for full-thickness skin wound healing. Decellularized skin extracellular matrix (ECM) powder was prepared via chemical treatment, freeze-drying and homogenization. The powder was mixed with culture medium containing hyaluronic acid to generate a pig skin gel (PSG). The effect of the gel in regeneration of full-thickness wound was studied in nude mice. We found significantly accelerated wound closure already on day 15 in animals treated with PSG only or PSG+hPBMC as compared to untreated and hyaluronic acid treated controls (p<0.05). Addition of the hPBMC to the gel resulted in marked increase of host blood vessels as well as the presence of human blood vessels. At day 25, histologically, the wounds in animals treated with PSG only or PSG+hPBMC were completely closed as compared to controls. Thus, the gel facilitated generation of new skin with well arranged epidermal cells and restored bilayer structure of the epidermis and dermis. These results suggest that porcine skin ECM gel together with human cells may be a novel and promising biomaterial for medical applications especially for patients with acute and chronic skin wounds.

Place, publisher, year, edition, pages
Cognizant Communication Corporation, 2017
National Category
Pharmacology and Toxicology Pharmaceutical Sciences Biomaterials Science
Identifiers
urn:nbn:se:ri:diva-27768 (URN)10.3727/096368916X692690 (DOI)27503828 (PubMedID)2-s2.0-85012224726 (Scopus ID)
Available from: 2017-01-06 Created: 2017-01-06 Last updated: 2019-01-10Bibliographically approved
Wetterskog, E., Castro, A., Zeng, L., Petronis, S., Heinke, D., Olsson, E., . . . Svedlindh, P. (2017). Size and property bimodality in magnetic nanoparticle dispersions: single domain particles vs. strongly coupled nanoclusters. Nanoscale, 9(12), 4227-4235
Open this publication in new window or tab >>Size and property bimodality in magnetic nanoparticle dispersions: single domain particles vs. strongly coupled nanoclusters
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2017 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 9, no 12, p. 4227-4235Article in journal (Refereed) Published
Abstract [en]

The widespread use of magnetic nanoparticles in the biotechnical sector puts new demands on fast and quantitative characterization techniques for nanoparticle dispersions. In this work, we report the use of asymmetric flow field-flow fractionation (AF4) and ferromagnetic resonance (FMR) to study the properties of a commercial magnetic nanoparticle dispersion. We demonstrate the effectiveness of both techniques when subjected to a dispersion with a bimodal size/magnetic property distribution: i.e., a small superparamagnetic fraction, and a larger blocked fraction of strongly coupled colloidal nanoclusters. We show that the oriented attachment of primary nanocrystals into colloidal nanoclusters drastically alters their static, dynamic, and magnetic resonance properties. Finally, we show how the FMR spectra are influenced by dynamical effects; agglomeration of the superparamagnetic fraction leads to reversible line-broadening; rotational alignment of the suspended nanoclusters results in shape-dependent resonance shifts. The AF4 and FMR measurements described herein are fast and simple, and therefore suitable for quality control procedures in commercial production of magnetic nanoparticles.

National Category
Nano Technology
Identifiers
urn:nbn:se:ri:diva-29219 (URN)10.1039/c7nr00023e (DOI)28290585 (PubMedID)2-s2.0-85016118237 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme
Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2019-01-10Bibliographically approved
Wells, J., Kazakova, O., Posth, O., Steinhoff, U., Petronis, S., Bogart, L., . . . Johansson, C. (2017). Standardisation of magnetic nanoparticles in liquid suspension. Journal of Physics D: Applied Physics, 50(383003), 1-25
Open this publication in new window or tab >>Standardisation of magnetic nanoparticles in liquid suspension
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2017 (English)In: Journal of Physics D: Applied Physics, Vol. 50, no 383003, p. 1-25Article in journal (Refereed) Published
Abstract [en]

Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation,spanning a large number of industry sectors from imaging and actuation based applicationsin biomedicine and biotechnology, through large-scale environmental remediation uses suchas water purification, to engineering-based applications such as position-controlled lubricantsand soaps. Continuous advances in their manufacture have produced an ever-growing rangeof products, each with their own unique properties. At the same time, the characterisation ofmagnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpretthe measurement data. In many cases, the stringent requirements of the end-user technologiesdictate that magnetic nanoparticle products should be clearly defined, well characterised,consistent and safe; or to put it another way—standardised. The aims of this document areto outline the concepts and terminology necessary for discussion of magnetic nanoparticles,to examine the current state-of-the-art in characterisation methods necessary for the mostprominent applications of magnetic nanoparticle suspensions, to suggest a possible structurefor the future development of standardisation within the field, and to identify areas and topicswhich deserve to be the focus of future work items. We discuss potential roadmaps for thefuture standardisation of this developing industry, and the likely challenges to be encounteredalong the way.

National Category
Nano Technology
Identifiers
urn:nbn:se:ri:diva-32363 (URN)10.1088/1361-6463/aa7fa5 (DOI)2-s2.0-85029007133 (Scopus ID)
Projects
NanoMag
Available from: 2017-10-24 Created: 2017-10-24 Last updated: 2019-06-27Bibliographically approved
Karazisis, D., Petronis, S., Agheli, H., Emanuelsson, L., Norlindh, B., Johansson, A., . . . Omar, O. (2017). The influence of controlled surface nanotopography on the early biological events of osseointegration.. Acta Biomaterialia, 53, 559-571
Open this publication in new window or tab >>The influence of controlled surface nanotopography on the early biological events of osseointegration.
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2017 (English)In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 53, p. 559-571Article in journal (Refereed) Published
Abstract [en]

The early cell and tissue interactions with nanopatterned titanium implants are insufficiently described in vivo. A limitation has been to transfer a pre-determined, well-controlled nanotopography to 3D titanium implants, without affecting other surface parameters, including surface microtopography and chemistry. This in vivo study aimed to investigate the early cellular and molecular events at the bone interface with screw-shaped titanium implants superimposed with controlled nanotopography. Polished and machined titanium implants were firstly patterned with 75-nm semispherical protrusions. Polished and machined implants without nano-patterns were designated as controls. Thereafter, all nanopatterned and control implants were sputter-coated with a 30nm titanium layer to unify the surface chemistry. The implants were inserted in rat tibiae and samples were harvested after 12h, 1d and 3d. In one group, the implants were unscrewed and the implant-adherent cells were analyzed using quantitative polymerase chain reaction. In another group, implants with surrounding bone were harvested en bloc for histology and immunohistochemistry. The results showed that nanotopography downregulated the expression of monocyte chemoattractant protein-1 (MCP-1), at 1d, and triggered the expression of osteocalcin (OC) at 3d. This was in parallel with a relatively lower number of recruited CD68-positive macrophages in the tissue surrounding the nanopatterned implants. Moreover, a higher proportion of newly formed osteoid and woven bone was found at the nanopatterned implants at 3d. It is concluded that nanotopography, per se, attenuates the inflammatory process and enhances the osteogenic response during the early phase of osseointegration. This nanotopography-induced effect appeared to be independent of the underlying microscale topography.

STATEMENT OF SIGNIFICANCE: This study provides a first line of evidence that pre-determined nanopatterns on clinically relevant, screw-shaped, titanium implants can be recognized by cells in the complex in vivo environment. Until now, most of the knowledge relating to cell interactions with nanopatterned surfaces has been acquired from in vitro studies involving mostly two-dimensional nanopatterned surfaces of varying chemical composition. We have managed to superimpose pre-determined nanoscale topography on polished and micro-rough, screw-shaped, implants, without changes in the microscale topography or chemistry. This was achieved by colloidal lithography in combination with a thin titanium film coating on top of both nanopatterned and control implants. The early events of osseointegration were evaluated at the bone interface to these implants. The results revealed that nanotopography, as such, elicits downregulatory effects on the early recruitment and activity of inflammatory cells while enhancing osteogenic activity and woven bone formation.

Keywords
Gene expression, In vivo, Nanotopography, Osseointegration, Titanium
National Category
Biomaterials Science
Identifiers
urn:nbn:se:ri:diva-29220 (URN)10.1016/j.actbio.2017.02.026 (DOI)28232253 (PubMedID)2-s2.0-85014028726 (Scopus ID)
Funder
VINNOVARegion Västra Götaland
Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2019-01-03Bibliographically approved
Karazisis, D., Ballo, A. M., Petronis, S., Agheli, H., Emanuelsson, L., Thomsen, P. & Omar, O. (2016). The role of well-defined nanotopography of titanium implants on osseointegration: Cellular and molecular events in vivo. International Journal of Nanomedicine, 11, 1367-1382
Open this publication in new window or tab >>The role of well-defined nanotopography of titanium implants on osseointegration: Cellular and molecular events in vivo
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2016 (English)In: International Journal of Nanomedicine, ISSN 1176-9114, E-ISSN 1178-2013, Vol. 11, p. 1367-1382Article in journal (Refereed) Published
Abstract [en]

Purpose: Mechanisms governing the cellular interactions with well-defined nanotopography are not well described in vivo. This is partly due to the difficulty in isolating a particular effect of nanotopography from other surface properties. This study employed colloidal lithography for nanofabrication on titanium implants in combination with an in vivo sampling procedure and different analytical techniques. The aim was to elucidate the effect of well-defined nanotopography on the molecular, cellular, and structural events of osseointegration. Materials and methods: Titanium implants were nanopatterned (Nano) with semispherical protrusions using colloidal lithography. Implants, with and without nanotopography, were implanted in rat tibia and retrieved after 3, 6, and 28 days. Retrieved implants were evaluated using quantitative polymerase chain reaction, histology, immunohistochemistry, and energy dispersive X-ray spectroscopy (EDS). Results: Surface characterization showed that the nanotopography was well defined in terms of shape (semispherical), size (79±6 nm), and distribution (31±2 particles/μm2). EDS showed similar levels of titanium, oxygen, and carbon for test and control implants, confirming similar chemistry. The molecular analysis of the retrieved implants revealed that the expression levels of the inflammatory cytokine, TNF-α, and the osteoclastic marker, CatK, were reduced in cells adherent to the Nano implants. This was consistent with the observation of less CD163-positive macrophages in the tissue surrounding the Nano implant. Furthermore, periostin immunostaining was frequently detected around the Nano implant, indicating higher osteogenic activity. This was supported by the EDS analysis of the retrieved implants showing higher content of calcium and phosphate on the Nano implants. Conclusion: The results show that Nano implants elicit less periimplant macrophage infiltration and downregulate the early expression of inflammatory (TNF-α) and osteoclastic (CatK) genes. Immunostaining and elemental analyses show higher osteogenic activity at the Nano implant. It is concluded that an implant with the present range of well-defined nanocues attenuates the inflammatory response while enhancing mineralization during osseointegration.

Place, publisher, year, edition, pages
Dove Medical Press Ltd., 2016
Keywords
Bone formation, Energy dispersive X-ray spectroscopy, Gene expression, Immunohistochemistry, Inflammatory cytokines, Nanofabrication
National Category
Biomaterials Science Dentistry
Identifiers
urn:nbn:se:ri:diva-85 (URN)10.2147/IJN.S101294 (DOI)2-s2.0-84962737306 (Scopus ID)
Available from: 2016-05-24 Created: 2016-04-28 Last updated: 2019-06-19Bibliographically approved
Svensson, S., Trobos, M., Hoffman, M., Norlindh, B., Petronis, S., Lausmaa, J., . . . Thomsen, P. (2015). A novel soft tissue model for biomaterial-associated infection and inflammation - Bacteriological, morphological and molecular observations (ed.). Biomaterials, 41, 106-121
Open this publication in new window or tab >>A novel soft tissue model for biomaterial-associated infection and inflammation - Bacteriological, morphological and molecular observations
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2015 (English)In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 41, p. 106-121Article in journal (Refereed) Published
Abstract [en]

Infection constitutes a major risk for implant failure, but the reasons why biomaterial sites are more vulnerable than normal tissue are not fully elucidated. In this study, a soft tissue infection model was developed, allowing the analysis of cellular and molecular responses in each of the sub-compartments of the implant-tissue interface (on the implant surface, in the surrounding exudate and in the tissue). Smooth and nanostructured titanium disks with or without noble metal chemistry (silver, gold, palladium), and sham sites, were inoculated with Staphylococcus epidermidis and analysed with respect to number of viable bacteria, number, viability and gene expression of host cells, and using different morphological techniques after 4 h, 24 h and 72 h. Non-infected rats were controls. Results showed a transient inflammatory response at control sites, whereas bacterial administration resulted in higher recruitment of inflammatory cells (mainly polymorphonuclear), higher, continuous cell death and higher gene expression of tumour necrosis factor-alpha, interleukin-6, interleukin-8, Toll-like receptor 2 and elastase. At all time points, S. epidermidis was predominantly located in the interface zone, extra- and intracellularly, and lower levels were detected on the implants compared with surrounding exudate. This model allows detailed analysis of early events in inflammation and infection associated to biomaterials in vivo leading to insights into host defence mechanisms in biomaterial-associated infections.

Keywords
Animal model, Bacteria, Infection, Inflammation, Nanotopography
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6795 (URN)10.1016/j.biomaterials.2014.11.032 (DOI)25522970 (PubMedID)23581 (Local ID)23581 (Archive number)23581 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-07-02Bibliographically approved
Sjövall, P., Lausmaa, J. & Petronis, S. (2014). Osteogenic response of human mesenchymal stem cells to well-defined nanoscale topography in vitro (ed.). International Journal of Nanomedicine, 9(1), 2499-2515
Open this publication in new window or tab >>Osteogenic response of human mesenchymal stem cells to well-defined nanoscale topography in vitro
2014 (English)In: International Journal of Nanomedicine, ISSN 1176-9114, E-ISSN 1178-2013, Vol. 9, no 1, p. 2499-2515Article in journal (Refereed) Published
Abstract [en]

Background: Patterning medical devices at the nanoscale level enables the manipulation of cell behavior and tissue regeneration, with topographic features recognized as playing a significant role inthe osseointegration of implantable devices. Methods: In this study, we assessed the ability of titanium-coated hemisphere-like topographic nanostructures of different sizes (approximately 50, 100, and 200 nm) to influence the morphology, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs). Results: We found that the proliferation and osteogenicdifferentiation of hMSCs was influenced by the size of the underlying structures, suggesting that size variations in topographic features at the nanoscale level, independently of chemistry, can be exploited to control hMSC behavior in a size-dependent fashion. Conclusion: Our studies demonstrate that colloidal lithography, in combination with coating technologies, can be exploited to investigate the cell response to well defined nanoscale topography and to develop next-generation surfaces that guide tissue regeneration and promote implant integration.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6740 (URN)10.2147/IJN.S58805 (DOI)2-s2.0-84901424254 (Scopus ID)23761 (Local ID)23761 (Archive number)23761 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-08-14Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4592-5851

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