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Mesarec L, Góźdź W, Iglič A, Kralj-Iglič V, Virga EG, Kralj S. Normal red blood cells' shape stabilized by membrane's in-plane ordering. Sci Rep 2019; 9:19742. [PMID: 31875042 PMCID: PMC6930264 DOI: 10.1038/s41598-019-56128-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/04/2019] [Indexed: 11/19/2022] Open
Abstract
Red blood cells (RBCs) are present in almost all vertebrates and their main function is to transport oxygen to the body tissues. RBCs' shape plays a significant role in their functionality. In almost all mammals in normal conditions, RBCs adopt a disk-like (discocyte) shape, which optimizes their flow properties in vessels and capillaries. Experimentally measured values of the reduced volume (v) of stable discocyte shapes range in a relatively broad window between v ~ 0.58 and 0.8. However, these observations are not supported by existing theoretical membrane-shape models, which predict that discocytic RBC shape is stable only in a very narrow interval of v values, ranging between v ~ 0.59 and 0.65. In this study, we demonstrate that this interval is broadened if a membrane's in-plane ordering is taken into account. We model RBC structures by using a hybrid Helfrich-Landau mesoscopic approach. We show that an extrinsic (deviatoric) curvature free energy term stabilizes the RBC discocyte shapes. In particular, we show on symmetry grounds that the role of extrinsic curvature is anomalously increased just below the nematic in-plane order-disorder phase transition temperature.
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Affiliation(s)
- L Mesarec
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - W Góźdź
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224, Warsaw, Poland
| | - A Iglič
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, 1000, Ljubljana, Slovenia
- Laboratory of Mass Spectrometry and Proteomics, Institute of Biosciences and BioResources, National Research Council of Italy, Napoli, 80132, Italy
| | - V Kralj-Iglič
- Laboratory of Mass Spectrometry and Proteomics, Institute of Biosciences and BioResources, National Research Council of Italy, Napoli, 80132, Italy
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, 1000, Ljubljana, Slovenia
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - E G Virga
- Department of Mathematics, University of Pavia, Via Ferrata 5, 27100, Pavia, Italy
| | - S Kralj
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, 2000, Maribor, Slovenia.
- Condensed Matter Physics Department, Jožef Stefan Institute, 1000, Ljubljana, Slovenia.
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Schara K, Štukelj R, Krek J, Lakota K, Sodin-Šemrl S, Boulton A, Kralj-Iglič V. A study of extracellular vesicle concentration in active diabetic Charcot neuroarthropathy. Eur J Pharm Sci 2017; 98:58-63. [DOI: 10.1016/j.ejps.2016.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 09/06/2016] [Accepted: 09/08/2016] [Indexed: 10/21/2022]
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Imani R, Pazoki M, Tiwari A, Boschloo G, Turner APF, Kralj-Iglič V, Iglič A. Band edge engineering of TiO2@DNA nanohybrids and implications for capacitive energy storage devices. Nanoscale 2015; 7:10438-10448. [PMID: 26001096 DOI: 10.1039/c5nr02533h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Novel mesoporous TiO2@DNA nanohybrid electrodes, combining covalently encoded DNA with mesoporous TiO2 microbeads using dopamine as a linker, were prepared and characterised for application in supercapacitors. Detailed information about donor density, charge transfer resistance and chemical capacitance, which have an important role in the performance of an electrochemical device, were studied by electrochemical methods. The results indicated the improvement of electrochemical performance of the TiO2 nanohybrid electrode by DNA surface functionalisation. A supercapacitor was constructed from TiO2@DNA nanohybrids with PBS as the electrolyte. From the supercapacitor experiment, it was found that the addition of DNA played an important role in improving the specific capacitance (Cs) of the TiO2 supercapacitor. The highest Cs value of 8 F g(-1) was observed for TiO2@DNA nanohybrids. The nanohybrid electrodes were shown to be stable over long-term cycling, retaining 95% of their initial specific capacitance after 1500 cycles.
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Affiliation(s)
- Roghayeh Imani
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia
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Kulkarni M, Mazare A, Gongadze E, Perutkova Š, Kralj-Iglič V, Milošev I, Schmuki P, Mozetič M. Titanium nanostructures for biomedical applications. Nanotechnology 2015; 26:062002. [PMID: 25611515 DOI: 10.1088/0957-4484/26/6/062002] [Citation(s) in RCA: 222] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.
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Affiliation(s)
- M Kulkarni
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana SI-1000, Slovenia. Department of Materials Science and Engineering, Chair of Surface Science and Corrosion, University of Erlangen-Nuremberg, WW4-LKO, Erlangen, Germany
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Rijavec B, Košak R, Daniel M, Kralj-Iglič V, Dolinar D. Effect of cup inclination on predicted contact stress-induced volumetric wear in total hip replacement. Comput Methods Biomech Biomed Engin 2014; 18:1468-73. [PMID: 24830356 DOI: 10.1080/10255842.2014.916700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In order to increase the lifetime of the total hip endoprosthesis, it is necessary to understand mechanisms leading to its failure. In this work, we address volumetric wear of the artificial cup, in particular the effect of its inclination with respect to the vertical. Volumetric wear was calculated by using mathematical models for resultant hip force, contact stress and penetration of the prosthesis head into the cup. Relevance of the dependence of volumetric wear on inclination of the cup (its abduction angle ϑA) was assessed by the results of 95 hips with implanted endoprosthesis. Geometrical parameters obtained from standard antero-posterior radiographs were taken as input data. Volumetric wear decreases with increasing cup abduction angle ϑA. The correlation within the population of 95 hips was statistically significant (P = 0.006). Large cup abduction angle minimises predicted volumetric wear but may increase the risk for dislocation of the artificial head from the cup in the one-legged stance. Cup abduction angle and direction of the resultant hip force may compensate each other to achieve optimal position of the cup with respect to wear and dislocation in the one-legged stance for a particular patient.
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Affiliation(s)
- B Rijavec
- a Laboratory of Clinical Biophysics, Faculty of Health Sciences , University of Ljubljana , Zdravstvena 5, SI-1000 Ljubljana , Slovenia
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Gongadze E, van Rienen U, Kralj-Iglič V, Iglič A. Spatial variation of permittivity of an electrolyte solution in contact with a charged metal surface: a mini review. Comput Methods Biomech Biomed Engin 2014. [DOI: 10.1080/10255842.2012.678684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Santhosh PB, Penič S, Genova J, Iglič A, Kralj-Iglič V, Ulrih NP. A study on the interaction of nanoparticles with lipid membranes and their influence on membrane fluidity. ACTA ACUST UNITED AC 2012. [DOI: 10.1088/1742-6596/398/1/012034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Gongadze E, van Rienen U, Kralj-Iglič V, Iglič A. Spatial variation of permittivity of an electrolyte solution in contact with a charged metal surface: a mini review. Comput Methods Biomech Biomed Engin 2012; 16:463-80. [PMID: 22263808 PMCID: PMC3664910 DOI: 10.1080/10255842.2011.624769] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 09/14/2011] [Indexed: 11/14/2022]
Abstract
Contact between a charged metal surface and an electrolyte implies a particular ion distribution near the charged surface, i.e. the electrical double layer. In this mini review, different mean-field models of relative (effective) permittivity are described within a simple lattice model, where the orientational ordering of water dipoles in the saturation regime is taken into account. The Langevin-Poisson-Boltzmann (LPB) model of spatial variation of the relative permittivity for point-like ions is described and compared to a more general Langevin-Bikerman (LB) model of spatial variation of permittivity for finite-sized ions. The Bikerman model and the Poisson-Boltzmann model are derived as limiting cases. It is shown that near the charged surface, the relative permittivity decreases due to depletion of water molecules (volume-excluded effect) and orientational ordering of water dipoles (saturation effect). At the end, the LPB and LB models are generalised by also taking into account the cavity field.
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Affiliation(s)
- E. Gongadze
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - U. van Rienen
- Faculty of Computer Science and Electrical Engineering, University of Rostock, Rostock, Germany
| | - V. Kralj-Iglič
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - A. Iglič
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
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Kabaso D, Gongadze E, Perutková Š, Matschegewski C, Kralj-Iglič V, Beck U, van Rienen U, Iglič A. Mechanics and electrostatics of the interactions between osteoblasts and titanium surface. Comput Methods Biomech Biomed Engin 2011; 14:469-82. [DOI: 10.1080/10255842.2010.534986] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kabaso D, Gongadze E, Elter P, van Rienen U, Gimsa J, Kralj-Iglič V, Iglič A. Attachment of rod-like (BAR) proteins and membrane shape. Mini Rev Med Chem 2011; 11:272-82. [PMID: 21428902 PMCID: PMC3343385 DOI: 10.2174/138955711795305353] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2010] [Revised: 03/03/2011] [Accepted: 12/24/2010] [Indexed: 11/22/2022]
Abstract
Previous studies have shown that cellular function depends on rod-like membrane proteins, among them Bin/Amphiphysin/Rvs (BAR) proteins may curve the membrane leading to physiologically important membrane invaginations and membrane protrusions. The membrane shaping induced by BAR proteins has a major role in various biological processes such as cell motility and cell growth. Different models of binding of BAR domains to the lipid bilayer are described. The binding includes hydrophobic insertion loops and electrostatic interactions between basic amino acids at the concave region of the BAR domain and negatively charged lipids. To shed light on the elusive binding dynamics, a novel experiment is proposed to expand the technique of single-molecule AFM for the traction of binding energy of a single BAR domain.
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Affiliation(s)
- D Kabaso
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia.
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Recnik G, Vengust R, Kralj-Iglič V, Vogrin M, Krajnc Z, Kramberger S. Association between Sub-Clinical Acetabular Dysplasia and a Younger Age at Hip Arthroplasty in Idiopathic Osteoarthritis. J Int Med Res 2009; 37:1620-1625. [DOI: 10.1177/147323000903700541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
This retrospective study was designed to investigate whether sub-clinical acetabular dysplasia, defined by a reduced centre-edge angle of Wiberg, was associated with a younger age at hip arthroplasty in patients with idiopathic osteoarthritis (OA). Fifty-four patients with 69 performed arthroplasties and no previous referral for hip dysplasia were selected from a list of consecutive recipients of hip endoprostheses due to idiopathic OA. The centre-edge angle was measured from standard pelvic radiographs taken a mean of 5.1 years prior to the endoprosthesis operation when there were minimal signs of hip OA. The age at which hip arthroplasty was carried out was compared between those patients with low (20° − 35°) and those with high (≥ 35°) centre-edge angles. The mean age at hip arthroplasty was significantly younger in the group with centre-edge angles of 20° − 35° (65.6 years) compared with those with centre-edge angles ≥ 35° (69.2 years). These results suggest that sub-clinical acetabular dysplasia was associated with a younger age at hip arthroplasty in idiopathic OA.
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Affiliation(s)
- G Recnik
- Department of Orthopaedic Surgery, University Hospital Maribor, Maribor, Slovenia
| | - R Vengust
- Department of Orthopaedic Surgery, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - V Kralj-Iglič
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - M Vogrin
- Department of Orthopaedic Surgery, University Hospital Maribor, Maribor, Slovenia
| | - Z Krajnc
- Department of Orthopaedic Surgery, University Hospital Maribor, Maribor, Slovenia
| | - S Kramberger
- Department of Orthopaedic Surgery, University Hospital Maribor, Maribor, Slovenia
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Kralj-Iglič V, Daniel M, Košak R, Antolič V, Iglič A. The influence of contact hip joint stress distribution on polyethylene cup wear. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)85177-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Daniel M, Iglič A, Kralj-Iglič V. Differences between the hip contact stresses measured experimentaly and estimated by mathematical models may be caused by local variations in the cartilage thickness and stiffness. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)83159-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Iglič A, Hägerstrand H, Fošnarič M, Kralj-Iglič V. On the role of anisotropy of membrane constituents in budding of a multicomponent membrane. J Biomech 2006. [DOI: 10.1016/s0021-9290(06)83919-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ipavec M, Brand R, Pedersen D, Mavčič B, Kralj-Iglič V, Iglič A. Erratum to: “Mathematical modelling of stress in the hip during gait” [Journal of Biomechanics, 32(11) (1999) 1229–1235]. J Biomech 2002. [DOI: 10.1016/s0021-9290(02)00012-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zupanc O, Antolič V, Iglič A, Jaklič A, Kralj-Iglič V, Stare J, Vengust R. The assessment of contact stress in the hip joint after operative treatment for severe slipped capital femoral epiphysis. Int Orthop 2001; 25:9-12. [PMID: 11374274 PMCID: PMC3620610 DOI: 10.1007/s002640000213] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We determined contact stress on the articular surface of the hip joint in a group of patients who underwent operative treatment for severe slipped capital femoral epiphysis. Two different procedures were considered: the modified osteotomy of Dunn-Fish and the osteotomy of Imhäuser. In order to determine the stress distribution, a three-dimensional mathematical model was used taking into account the geometrical parameters of the pelvis and hip, which were measured from standard antero-posterior radiographs. We found that the Dunn-Fish procedure produced lower peak stress than the Imhäuser procedure.
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Affiliation(s)
- O. Zupanc
- />Department of Orthopaedic Surgery, Zaloška 9, SI-1000 Ljubljana, Slovenia, Slovenia
| | - V. Antolič
- />Department of Orthopaedic Surgery, Zaloška 9, SI-1000 Ljubljana, Slovenia, Slovenia
| | - A. Iglič
- />Faculty of Electrical Engineering, Laboratory of Applied Physics, Tržaška 25, SI-1000 Ljubljana, Slovenia, Slovenia
| | - A. Jaklič
- />Institute of Metal Technology-IMT Ljubljana, Lepi pot 11, SI-1000 Ljubljana, Slovenia, Slovenia
| | - V. Kralj-Iglič
- />Department of Orthopaedic Surgery, Zaloška 9, SI-1000 Ljubljana, Slovenia, Slovenia
| | - J. Stare
- />Institute of Biomedical Informatics, Medical Faculty, Vrazov trg 2, SI-1000 Ljubljana, Slovenia, Slovenia
| | - R. Vengust
- />Department of Orthopaedic Surgery, Zaloška 9, SI-1000 Ljubljana, Slovenia, Slovenia
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