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Deng Y, Zhou C, Fu L, Huang X, Liu Z, Zhao J, Liang W, Shao H. A mini-review on the emerging role of nanotechnology in revolutionizing orthopedic surgery: challenges and the road ahead. Front Bioeng Biotechnol 2023; 11:1191509. [PMID: 37260831 PMCID: PMC10228697 DOI: 10.3389/fbioe.2023.1191509] [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: 03/22/2023] [Accepted: 05/02/2023] [Indexed: 06/02/2023] Open
Abstract
An emerging application of nanotechnology in medicine currently being developed involves employing nanoparticles to deliver drugs, heat, light, or other substances to specific types of cells (such as cancer cells). As most biological molecules exist and function at the nanoscale, engineering and manipulating matter at the molecular level has many advantages in the field of medicine (nanomedicine). Although encouraging, it remains unclear how much of this will ultimately result in improved patient care. In surgical specialties, clinically relevant nanotechnology applications include the creation of surgical instruments, suture materials, imaging, targeted drug therapy, visualization methods, and wound healing techniques. Burn lesion and scar management is an essential nanotechnology application. Prevention, diagnosis, and treatment of numerous orthopedic conditions are crucial technological aspects for patients' functional recovery. Orthopedic surgery is a specialty that deals with the diagnosis and treatment of musculoskeletal disorders. In recent years, the field of orthopedics has been revolutionized by the advent of nanotechnology. Using biomaterials comprised of nanoparticles and structures, it is possible to substantially enhance the efficacy of such interactions through nanoscale material modifications. This serves as the foundation for the majority of orthopedic nanotechnology applications. In orthopedic surgery, nanotechnology has been applied to improve surgical outcomes, enhance bone healing, and reduce complications associated with orthopedic procedures. This mini-review summarizes the present state of nanotechnology in orthopedic surgery, including its applications as well as possible future directions.
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Affiliation(s)
- Yongjun Deng
- Department of Orthopedics, Affiliated Hospital of Shaoxing University, Shaoxing, China
| | - Chao Zhou
- Department of Orthopedics, Zhoushan Guanghua Hospital, Zhoushan, China
| | - Lifeng Fu
- Department of Orthopedics, Shaoxing City Keqiao District Hospital of Traditional Chinese Medicine, Shaoxing, China
| | - Xiaogang Huang
- Department of Orthopedics, Zhoushan Hospital of Traditional Chinese Medicine Affiliated to Zhejiang Chinese Medical University, Zhoushan, China
| | - Zunyong Liu
- Department of Orthopedics, Zhoushan Hospital of Traditional Chinese Medicine Affiliated to Zhejiang Chinese Medical University, Zhoushan, China
| | - Jiayi Zhao
- Department of Orthopedics, Zhoushan Hospital of Traditional Chinese Medicine Affiliated to Zhejiang Chinese Medical University, Zhoushan, China
| | - Wenqing Liang
- Department of Orthopedics, Zhoushan Hospital of Traditional Chinese Medicine Affiliated to Zhejiang Chinese Medical University, Zhoushan, China
| | - Haiyan Shao
- Department of Orthopedics, Zhoushan Hospital of Traditional Chinese Medicine Affiliated to Zhejiang Chinese Medical University, Zhoushan, China
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Silva Barreto I, Le Cann S, Ahmed S, Sotiriou V, Turunen MJ, Johansson U, Rodriguez‐Fernandez A, Grünewald TA, Liebi M, Nowlan NC, Isaksson H. Multiscale Characterization of Embryonic Long Bone Mineralization in Mice. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2002524. [PMID: 33173750 PMCID: PMC7610310 DOI: 10.1002/advs.202002524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Indexed: 06/01/2023]
Abstract
Long bone mineralization occurs through endochondral ossification, where a cartilage template mineralizes into bone-like tissue with a hierarchical organization from the whole bone-scale down to sub-nano scale. Whereas this process has been extensively studied at the larger length scales, it remains unexplored at some of the smaller length scales. In this study, the changes in morphology, composition, and structure during embryonic mineralization of murine humeri are investigated using a range of high-resolution synchrotron-based imaging techniques at several length scales. With micro- and nanometer spatial resolution, the deposition of elements and the shaping of mineral platelets are followed. Rapid mineralization of the humeri occurs over approximately four days, where mineral to matrix ratio and calcium content in the most mineralized zone reach adult values shortly before birth. Interestingly, zinc is consistently found to be localized at the sites of ongoing new mineralization. The mineral platelets in the most recently mineralized regions are thicker, longer, narrower, and less aligned compared to those further into the mineralized region. In summary, this study demonstrates a specific spatial distribution of zinc, with highest concentration where new mineral is being deposited and that the newly formed mineral platelets undergo slight reshaping and reorganization during embryonic development.
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Affiliation(s)
| | - Sophie Le Cann
- Department of Biomedical EngineeringLund UniversityLund22100Sweden
| | - Saima Ahmed
- Department of BioengineeringImperial College LondonLondonSW72AZUK
| | - Vivien Sotiriou
- Department of BioengineeringImperial College LondonLondonSW72AZUK
| | - Mikael J. Turunen
- Department of Applied PhysicsUniversity of Eastern FinlandKuopio70211Finland
| | | | | | | | - Marianne Liebi
- Department of PhysicsChalmers University of TechnologyGothenburg41296Sweden
| | - Niamh C. Nowlan
- Department of BioengineeringImperial College LondonLondonSW72AZUK
| | - Hanna Isaksson
- Department of Biomedical EngineeringLund UniversityLund22100Sweden
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Cassini C, Wittmeier A, Brehm G, Denz M, Burghammer M, Köster S. Large field-of-view scanning small-angle X-ray scattering of mammalian cells. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:1059-1068. [PMID: 33566016 PMCID: PMC7336178 DOI: 10.1107/s1600577520006864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 05/21/2020] [Indexed: 06/12/2023]
Abstract
X-ray imaging is a complementary method to electron and fluorescence microscopy for studying biological cells. In particular, scanning small-angle X-ray scattering provides overview images of whole cells in real space as well as local, high-resolution reciprocal space information, rendering it suitable to investigate subcellular nanostructures in unsliced cells. One persisting challenge in cell studies is achieving high throughput in reasonable times. To this end, a fast scanning mode is used to image hundreds of cells in a single scan. A way of dealing with the vast amount of data thus collected is suggested, including a segmentation procedure and three complementary kinds of analysis, i.e. characterization of the cell population as a whole, of single cells and of different parts of the same cell. The results show that short exposure times, which enable faster scans and reduce radiation damage, still yield information in agreement with longer exposure times.
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Affiliation(s)
- Chiara Cassini
- Institute for X-ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells (MBExC)’, University of Göttingen, Germany
| | - Andrew Wittmeier
- Institute for X-ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Gerrit Brehm
- Institute for X-ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells (MBExC)’, University of Göttingen, Germany
| | - Manuela Denz
- Institute for X-ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Manfred Burghammer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Sarah Köster
- Institute for X-ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
- Cluster of Excellence ‘Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells (MBExC)’, University of Göttingen, Germany
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Zhang Y, Buchanan JK, Holmes G, Mansel BW, Prabakar S. Collagen structure changes during chrome tanning in propylene carbonate. JOURNAL OF LEATHER SCIENCE AND ENGINEERING 2019. [DOI: 10.1186/s42825-019-0011-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Vordos N, Drosos G, Kazanidis I, Ververidis A, Ypsilantis P, Kazakos K, Simopoulos C, Mitropoulos AC, Touloupidis S. Hydroxyapatite Crystal Thickness and Buckling Phenomenon in Bone Nanostructure During Mechanical Tests. Ann Biomed Eng 2018; 46:627-639. [DOI: 10.1007/s10439-018-1983-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 01/12/2018] [Indexed: 12/22/2022]
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Pabisch S, Akabane C, Wagermaier W, Roschger A, Ogura T, Hyodo R, Kataoka S, Tobori N, Okano T, Murakami S, Fratzl P, Weinkamer R. The nanostructure of murine alveolar bone and its changes due to type 2 diabetes. J Struct Biol 2016; 196:223-231. [PMID: 27637572 DOI: 10.1016/j.jsb.2016.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 06/14/2016] [Accepted: 09/12/2016] [Indexed: 12/29/2022]
Abstract
Alveolar bone - the bony ridge containing the tooth sockets - stands out by its remodeling activity where bone is being formed and resorbed at a much higher rate than in any other bony tissue. Teeth that are anchored in the jaw through the periodontal ligament exert very large localized loads during mastication that could lead to a unique adaptation of the collagen/mineral structure in the bone. Our aim was to characterize the nanostructure of alveolar bone and to determine the influence of diabetes on structural characteristics of the mineralized matrix. Using small- and wide-angle X-ray scattering (SAXS/WAXS), we studied a spontaneous diabetic mouse model (KK+) and its corresponding healthy controls (KK-) (n=6) to determine the size and mutual alignment of the mineral nanoparticles embedded in the collagen matrix. On cross-sections (buccal-lingual) of the first molar multiple line scans with a spatial resolution of 30μm were performed on each sample, from the lingual to the buccal side of the mandible. Mineral particle thickness and length are decreasing towards the tooth in both buccal and lingual sides of alveolar bone. While mineral particles are well aligned with the long axis of the tooth on the buccal side, they are in a quarter of the measurements oriented along two preferred directions on the lingual side. These nanostructural differences can be interpreted as the result of an asymmetric loading during mastication, leading to a tilting of the tooth in its socket. In diabetic mice particle thicknesses are smaller compared to control animals.
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Affiliation(s)
- Silvia Pabisch
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Chika Akabane
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany; Functional Materials Science Research Laboratories, Research & Development Headquarters, LION Corporation, Tokyo, Japan
| | - Wolfgang Wagermaier
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Andreas Roschger
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
| | - Taku Ogura
- Functional Materials Science Research Laboratories, Research & Development Headquarters, LION Corporation, Tokyo, Japan
| | - Ryo Hyodo
- Functional Materials Science Research Laboratories, Research & Development Headquarters, LION Corporation, Tokyo, Japan
| | - Shinsuke Kataoka
- Life Science Research Laboratories, Research & Development Headquarters, LION Corporation, Kanagawa, Japan
| | - Norio Tobori
- Functional Materials Science Research Laboratories, Research & Development Headquarters, LION Corporation, Tokyo, Japan
| | - Tomomichi Okano
- Research & Development Headquarters, LION Corporation, Tokyo, Japan
| | - Shinya Murakami
- Department of Periodontology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Peter Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Richard Weinkamer
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
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Prein C, Warmbold N, Farkas Z, Schieker M, Aszodi A, Clausen-Schaumann H. Structural and mechanical properties of the proliferative zone of the developing murine growth plate cartilage assessed by atomic force microscopy. Matrix Biol 2016; 50:1-15. [DOI: 10.1016/j.matbio.2015.10.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 09/25/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022]
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Grünewald T, Ogier A, Akbarzadeh J, Meischel M, Peterlik H, Stanzl-Tschegg S, Löffler J, Weinberg A, Lichtenegger H. Reaction of bone nanostructure to a biodegrading Magnesium WZ21 implant - A scanning small-angle X-ray scattering time study. Acta Biomater 2016; 31:448-457. [PMID: 26621693 DOI: 10.1016/j.actbio.2015.11.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/28/2015] [Accepted: 11/23/2015] [Indexed: 01/07/2023]
Abstract
Understanding the implant-bone interaction is of prime interest for the development of novel biodegrading implants. Magnesium is a very promising material in the class of biodegrading metallic implants, owing to its mechanical properties and excellent immunologic response during healing. However, the influence of degrading Mg implants on the bone nanostructure is still an open question of crucial importance for the design of novel Mg implant alloys. This study investigates the changes in the nanostructure of bone following the application of a degrading WZ21 Mg implant (2wt% Y, 1wt% Zn, 0.25wt% Ca and 0.15wt% Mn) in a murine model system over the course of 15months by small angle X-ray scattering. Our investigations showed a direct response of the bone nanostructure after as little as 1month with a realignment of nano-sized bone mineral platelets along the bone-implant interface. The growth of new bone tissue after implant resorption is characterized by zones of lower mineral platelet thickness and slightly decreased order in the stacking of the platelets. The preferential orientation of the mineral platelets strongly deviates from the normal orientation along the shaft and still roughly follows the implant direction after 15months. We explain our findings by considering geometrical, mechanical and chemical factors during the process of implant resorption. STATEMENT OF SIGNIFICANCE The advancement of surgical techniques and the increased life expectancy have caused a growing demand for improved bone implants. Ideally, they should be bio-resorbable, support bone as long as necessary and then be replaced by healthy bone tissue. Magnesium is a promising candidate for this purpose. Various studies have demonstrated its excellent mechanical performance, degradation behaviour and immunologic properties. The structural response of bone, however, is not well known. On the nanometer scale, the arrangement of collagen fibers and calcium mineral platelets is an important indicator of structural integrity. The present study provides insight into nanostructural changes in rat bone at different times after implant placement and different implant degradation states. The results are useful for further improved magnesium alloys.
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Acerbo AS, Kwaczala AT, Yang L, Judex S, Miller LM. Alterations in collagen and mineral nanostructure observed in osteoporosis and pharmaceutical treatments using simultaneous small- and wide-angle X-ray scattering. Calcif Tissue Int 2014; 95:446-56. [PMID: 25190190 DOI: 10.1007/s00223-014-9913-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 08/22/2014] [Indexed: 12/27/2022]
Abstract
The influence of the macroscale material properties of bone on its mechanical competence has been extensively investigated, but less is known about possible contributions from bone's nanoscale material properties. These nanoscale properties, particularly the collagen network and the size and shape of hydroxyapatite mineral crystals, may be affected by aging, mechanical loading, and diseases including osteoporosis. Here, changes to the collagen and mineral properties of cortical bone induced by osteoporosis and subsequent pharmaceutical treatments were investigated by simultaneous small- and wide-angle X-ray scattering (SAXS/WAXS) microbeam mapping. Adult rats (6 months old) were ovariectomized and treated with alendronate, parathyroid hormone, or sodium fluoride, and compared to untreated ovariectomized and age-matched controls. Scattering data from tibial cortical bone showed that osteoporosis increased collagen alignment in existing intracortical bone, while this effect was mitigated in the alendronate and sodium fluoride groups though by different mechanisms. Further, mineral crystal lengths in newly formed cortical bone were smaller in animals with osteoporosis, but existing cortical bone was not altered. Subsequent treatment with alendronate mitigated changes in crystal lengths. Together, these results suggest that osteoporosis may alter the collagen alignment and mineral geometry in bone formed before and after the onset of this disease, and that osteoporosis treatments may differentially rescue these changes.
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Affiliation(s)
- Alvin S Acerbo
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA
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Abstract
Nanotechnology applications in medicine are poised to revolutionize the prevention, diagnosis, and treatment of disease. Researchers, scientists, and physicians across various disciplines and specialties are working to develop innovative clinical tools that incorporate materials, devices, and systems engineered at the nanoscale. Surgical specialties, such as orthopedic surgery, are among those developing nanotechnology applications for clinical use. Orthopedic surgery addresses disorders of the musculoskeletal system including repair by both surgical and nonsurgical means of tendons, ligaments, muscles, bones, and nerves injured due to trauma or disease. Medical interventions targeting orthopedic conditions are becoming increasingly important given current epidemiologic trends in these conditions. The purpose of this article is to highlight current and emerging applications of nanotechnology in orthopedic surgery. Selected, clinically relevant examples are described in the categories of drugs and drug delivery, imaging, sensors, biomaterials, diagnostics, and novel therapeutics. Several promising nanomedicine applications that target orthopedic conditions are in various stages of development from basic scientific research to clinical trials to product development and commercialization. Nanotechnology applications aimed at the prevention, diagnosis, and treatment of orthopedic conditions hold great promise for improving the standard of care in orthopedic surgery in the 21st century.
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Affiliation(s)
- Sara A. Brenner
- UAlbany College of Nanoscale Science and Engineering, Nanobioscience Constellation, 257 Fuller Road, NanoFab East, Room 4406, Albany, NY 12203 e-mail:
| | - John F. Ling
- Indiana University School of Medicine, MS1, 340 West 10th Street, Suite 6200, Indianapolis, IN 46202-3082 e-mail:
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Liu Y, Manjubala I, Schell H, Epari DR, Roschger P, Duda GN, Fratzl P. Size and habit of mineral particles in bone and mineralized callus during bone healing in sheep. J Bone Miner Res 2010; 25:2029-38. [PMID: 20225262 DOI: 10.1002/jbmr.84] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bone healing is known to occur through the successive formation and resorption of various tissues with different structural and mechanical properties. To get a better insight into this sequence of events, we used environmental scanning electron microscopy (ESEM) together with scanning small-angle X-ray scattering (sSAXS) to reveal the size and orientation of bone mineral particles within the regenerating callus tissues at different healing stages (2, 3, 6, and 9 weeks). Sections of 200 µm were cut from embedded blocks of midshaft tibial samples in a sheep osteotomy model with an external fixator. Regions of interest on the medial side of the proximal fragment were chosen to be the periosteal callus, middle callus, intercortical callus, and cortex. Mean thickness (T parameter), degree of alignment (ρ parameter), and predominant orientation (ψ parameter) of mineral particles were deduced from resulting sSAXS patterns with a spatial resolution of 200 µm. 2D maps of T and ρ overlapping with ESEM images revealed that the callus formation occurred in two waves of bone formation, whereby a highly disordered mineralized tissue was deposited first, followed by a bony tissue with more lamellar appearance in the ESEM and where the mineral particles were more aligned, as revealed by sSAXS. As a consequence, degree of alignment and mineral particle size within the callus increased with healing time, whereas at any given moment there were structural gradients, for example, from periosteal toward the middle callus.
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Affiliation(s)
- Yifei Liu
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
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From diffraction to imaging: New avenues in studying hierarchical biological tissues with x-ray microbeams (Review). Biointerphases 2010; 3:FB16. [PMID: 20408678 DOI: 10.1116/1.2955443] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Load bearing biological materials such as bone or arthropod cuticle have optimized mechanical properties which are due to their hierarchical structure ranging from the atomic/molecular level up to macroscopic length scales. Structural investigations of such materials require new experimental techniques with position resolution ideally covering several length scales. Beside light and electron microscopy, synchrotron radiation based x-ray imaging techniques offer excellent possibilities in this respect, ranging from full field imaging with absorption or phase contrast to x-ray microbeam scanning techniques. A particularly useful approach for the study of biological tissues is the combination x-ray microbeam scanning with nanostructural information obtained from x-ray scattering [small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS)]. This combination allows constructing quantitative images of nanostructural parameters with micrometer scanning resolution, and hence, covers two length scales at once. The present article reviews recent scanning microbeam SAXS/WAXS work on bone and some other biological tissues with particular emphasis on the imaging capability of the method. The current status of instrumentation and experimental possibilities is also discussed, and a short outlook about actual and desirable future developments in the field is given.
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Bünger MH, Oxlund H, Hansen TK, Sørensen S, Bibby BM, Thomsen JS, Langdahl BL, Besenbacher F, Pedersen JS, Birkedal H. Strontium and bone nanostructure in normal and ovariectomized rats investigated by scanning small-angle X-ray scattering. Calcif Tissue Int 2010; 86:294-306. [PMID: 20221590 DOI: 10.1007/s00223-010-9341-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 02/02/2010] [Indexed: 11/29/2022]
Abstract
The effect of SrCl(2) treatment on bone nanostructure in a rat ovariectomy model was studied using scanning small-angle X-ray scattering (sSAXS). Twelve 6-month-old female Wistar rats were used. Six animals were ovariectomized (+ovx) and six were left intact after sham surgery (-ovx). Six animals, three +ovx and three -ovx, were treated with 4 mmol SrCl(2) (aq)/kg/day (+Sr), whereas the remaining six received placebo (-Sr) for 140 days. Rats were labeled with flourochromes at days 7, 126, and 136. Femoral cross sections were studied using fluorescence microscopy, scanning electron microscopy including energy-dispersive X-ray analysis, and sSAXS. The SAXS data comprised about 5,500 measurements and provided information about mineral crystal thickness and orientation in new and old bone. The newly formed bone contained higher levels of Sr(2+) in +Sr than in -Sr animals, indicating that the Sr(2+) was incorporated into the new bone. Mineral plates were significantly thicker in old bone, 2.62 nm (95% CI 2.58-2.66), than in new bone, 2.41 nm (95% CI 2.36-2.46). Surprisingly, mineral plates in new bone were significantly thicker (2.52 [95% CI 2.47-2.57] nm vs. 2.41 [95% CI 2.36-2.46] nm, P = 0.017) in +ovx rats than in -ovx rats. However, no significant effect of SrCl(2) on mineral plate thicknesses in new bone was observed. The statistical model yielded estimates of the difference in bone mineral plate thickness induced by Sr. The estimated effect of Sr was -0.09 (95% CI -0.21 to 0.03) and 0.02 (95% CI -0.10 to 0.14) nm for new bone in -ovx and +ovx rats, respectively.
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Affiliation(s)
- Mathias H Bünger
- Department of Endocrinology and Metabolism C, Aarhus University Hospital, Arhus, Denmark.
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Aladin DMK, Cheung KMC, Ngan AHW, Chan D, Leung VYL, Lim CT, Luk KDK, Lu WW. Nanostructure of collagen fibrils in human nucleus pulposus and its correlation with macroscale tissue mechanics. J Orthop Res 2010; 28:497-502. [PMID: 19862800 DOI: 10.1002/jor.21010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Collagen fibrils are the main structural components of the nucleus pulposus tissue in the intervertebral discs. The structure-property relationship of the nucleus pulposus (NP) tissues is still unclear. We investigated the structure of individual collagen fibrils of the NP and evaluated its correlation with the bulk mechanical properties of the tissue. Collagen fibrils were extracted from the NP of discs retrieved from adolescents during scoliosis correction surgery, and the extracts were confirmed by SDS-PAGE. The diameters of the individual collagen fibrils were measured through atomic force microscopy, and the compressive mechanical properties of the tissues were evaluated by confined compression. The correlations between the nanoscale morphology of the collagen fibrils and the macroscale mechanical properties of the tissues were evaluated by linear regression. The SDS-PAGE results showed that the fibril extracts were largely composed of type II collagen. The mean diameter of the collagen fibrils was 92.1 +/- 26.54 nm; the mean swelling pressure and compressive modulus of the tissues were 6.15 +/- 4.3 kPa and 1.23 +/- 0.7 MPa, respectively. The mean fibril diameter had no linear correlation (R(2) = 0.30) with the swelling pressure of the tissues. However, it had a mild linear correlation with the compressive modulus (p = 0.023, R(2) = 0.68). This is the first study, to our knowledge, to evaluate the nanostructure of the individual collagen fibrils of the nucleus pulposus and its relationship with macroscale mechanical properties of the NP tissues.
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Affiliation(s)
- Darwesh M K Aladin
- Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong, China
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Schack NB, Oliveira CLP, Young NWG, Pedersen JS, Ogilby PR. Oxygen diffusion in cross-linked, ethanol-swollen poly(vinyl alcohol) gels: counter-intuitive results reflect microscopic heterogeneities. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:1148-1153. [PMID: 19099533 DOI: 10.1021/la803024h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Oxygen diffusion coefficients have been determined in ethanol-swollen poly(vinyl alcohol), PVA, gels using a technique wherein oxygen sorption is optically monitored using singlet oxygen phosphorescence. Data were recorded as a function of the extent to which the PVA chains are chemically cross-linked using glutaraldehyde. Contrary to conventional expectation, the diffusion coefficients obtained increase with an increase in the extent of cross-linking. This observation is interpreted in terms of a cross-link-dependent increase in the microscopic heterogeneity of the polymer wherein dense cross-linked domains coexist with more fluid domains. It is expected that, in the latter domains, segmental motions of the macromolecule that facilitate oxygen diffusion are more readily achieved. This model of cross-link-dependent heterogeneity is supported by the results of small-angle X-ray scattering experiments. Among other things, the data reported herein provide an informative foundation for studies of small molecule diffusion in biological cells, particularly during photoinduced cell death where the hydrogel-like nature of the cell can change due to cross-linking reactions.
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Affiliation(s)
- Nickolass Bitsch Schack
- Center for Oxygen Microscopy and Imaging, Department of Chemistry, and The Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, DK-8000 Arhus, Denmark
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