Article
Chemistry, Multidisciplinary
Ulrike Doering, Dmitry Grigoriev, Tino Riske, Andreas Fery, Alexander Boeker
Summary: The mechanical properties of proteinaceous and composite microcapsules loaded with oil were measured using SFM and evaluated with the Reissner model. The results showed significantly higher Young's moduli in protein capsules due to intermolecular crosslinking, while conformational restrictions in composite microcapsules led to reduced elasticity.
Article
Chemistry, Multidisciplinary
Emilie Gachon, Patrick Mesquida
Summary: Collagen fibrils exhibit a surface charge dependency on longitudinal strain, becoming more positive within 10% strain and more negative between 10% to 17% strain. This change is correlated with fibril stiffness and may be influenced by structural rearrangements. Kelvin-probe force microscopy testing on fibrils attached to an extensible, thin polymer film allows for the determination of electrical surface potential.
Article
Chemistry, Physical
Matthew P. Leighton, Laurent Kreplak, Andrew D. Rutenberg
Summary: This study proposes a new mechanism for fiber formation, suggesting that enzymatic cross-links occur on the surface of collagen fibers and incorporating the orientation of collagen molecules and periodic D-band density modulation in the proposed model. Radial growth is controlled by the concentration of available collagen molecules outside the fiber, and the fiber structure is determined by the radius.
Article
Engineering, Biomedical
Heonjune Ryou, Franklin R. Tay, Alex Ossa, Dwayne Arola
Summary: This study presents a new experimental methodology for preparing samples of dentinal collagen fibrils and evaluating their mechanical behavior using atomic force microscopy. Dynamic mechanical analysis was performed to study the viscoelastic behavior of the fibrils, and measures of energy dissipation, phase angle, and loss modulus were used to characterize their capacity for viscous dampening. The peak regions of the fibrils showed significantly greater stiffness and dampening capacity than the trough regions, as indicated by the phase angle and loss modulus. This new approach will contribute to understanding the role of collagen fibrils in the mechanical behavior of dentin and other mineralized tissues, as well as the potential effects from changes in fibril confirmation due to tissue treatments, aging, or chronic diseases.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
K. P. Sonu, Le Zhou, Santidan Biswas, John Klier, Anna C. Balazs, Todd Emrick, Shelly R. Peyton
Summary: Hydrogels are water-swollen networks that have various applications in biomaterials and biotechnology. This study successfully synthesized multifunctional polymers to create hydrogels with reversible and irreversible cross-links. These strain-stiffening hydrogels have potential applications as biomaterials, particularly in emerging fields like tissue engineering.
Review
Chemistry, Multidisciplinary
Wei-Hua Han, Qing-Yu Wang, Yuan-Yi Kang, Li-Rui Shi, Yu Long, Xin Zhou, Chun-Cheng Hao
Summary: This review comprehensively discusses the cross-linking electrospinning system for the first time, including cross-linking strategies, cross-linking mechanisms, and applications of cross-linked electrospun nanofibers. The significance of cross-linking electrospinning and the challenges in constructing this system are also highlighted.
Article
Chemistry, Physical
Arwa Bazaid, Fengyuan Zhang, Qiancheng Zhang, Sabine Neumayer, Denise Denning, Stefan Habelitz, Ana Marina Ferreira, Brian J. Rodriguez
Summary: Since the discovery of piezoelectricity in bone in 1957, there has been a debate about the functional role of collagen piezoelectricity. The investigation of piezoelectricity in collagen has generated interest in bone remodeling, but there are conflicting reports about its presence in a humid environment. This study used lateral piezoresponse force microscopy to investigate the electromechanical properties of type I collagen from a rat tail tendon at the nanoscale, and found that collagen retains its piezoelectric behavior even in a biologically relevant humidity range.
Review
Anatomy & Morphology
Shuaiyuan Liu, Yibo Han, Lingwen Kong, Guixue Wang, Zhiyi Ye
Summary: Atomic force microscopy shows promise as a clinical device to diagnose and treat challenging diseases by examining the surface morphology and assessing tissue and cellular mechanics of biological specimens in a physiological setting.
MICROSCOPY RESEARCH AND TECHNIQUE
(2023)
Article
Engineering, Biomedical
Julian Sartori, Heiko Stark
Summary: This study analyzed the 3D fiber tracks in macroscopic tendon samples, revealing that the insertion is not reinforced in terms of fiber numbers or sizes. The orientation of fibers in the tendon center is higher than in the margins, which could inspire material development. Fibers inserting at a protrusion of the insertion area stem from a distinct portion within the tendon, suggesting that fibrous structure analysis can link macro- to micromechanics.
ACTA BIOMATERIALIA
(2021)
Article
Chemistry, Analytical
Tanveer Ahmed Shaik, Enrico Baria, Xinyue Wang, Florian Korinth, Joao L. Lagarto, Christiane Hoeppener, Francesco S. Pavone, Volker Deckert, Juergen Popp, Riccardo Cicchi, Christoph Krafft
Summary: This study investigated the biochemical, structural, and biomechanical effects of genipin (GE) cross-linking on equine pericardium (EP) using optical imaging techniques and atomic force microscopy (AFM). Results showed that GE cross-linking led to a decrease in second-harmonic signal and an increase in autofluorescence, indicating changes in biochemical and structural properties. Additionally, cross-linking increased the Young's modulus of EP.
ANALYTICAL CHEMISTRY
(2022)
Review
Biochemistry & Molecular Biology
Zhaoming Deng, Jun Liang, Na Fang, Xiangwei Li
Summary: Dental implants are widely accepted due to their mechanical properties and aesthetic outcomes. Successful osseointegration and tight soft tissue integration, particularly collagen fibers in the transmucosal region, contribute to their restorative success. Surface modification methods can enhance soft tissue integration. This review focuses on the differences in the transmucosal zone around dental implants compared to natural teeth and explores the latest strategies for enhancing soft tissue integration.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2022)
Article
Biophysics
Atsushi Maejima, Kenta Ishibashi, Hyonchol Kim, Izumi Kumagai, Ryutaro Asano
Summary: This study established a novel method using atomic force microscopy combined with a metal cup-attached chip to measure the cross-linking ability of bispecific antibodies and correlate it with cytotoxicity. The results showed that the forces mediated by bsAbs with different domain orders during intercellular cross-linking were well-correlated with their cytotoxicities.
BIOSENSORS & BIOELECTRONICS
(2021)
Article
Chemistry, Applied
Yunfei Wan, Yongfang Gao, Jianhang Shao, Aidana Tumarbekova, Dequan Zhang, Jie Zhu
Summary: This study investigated the ultrastructure and mechanical characteristics of collagen fibers in tendons, revealing that collagen fibers extracted from acetic acid are more unstable compared to homogenized collagen fibers. Acetic acid was found to disassemble salt bonds and Schiff-base in collagen, resulting in looser collagen fibers while maintaining the integrity of the triple helix structure.
Article
Biochemistry & Molecular Biology
Pauline Cornette, Ilhem Lilia Jaabar, Vincent Dupres, Jean-David Werthel, Francis Berenbaum, Xavier Houard, Jessem Landoulsi, Geoffroy Nourissat
Summary: The study investigated the effect of crosslinking treatment on the structure and mechanical properties of diseased human shoulder capsules. The results showed that the crosslinking procedure changed the biomechanics of the capsules while keeping their structural organization unchanged at the single fibril level. This procedure may be a promising way to preserve the functions of collagen-based tissues and tune their elasticity for clinically relevant treatments.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Engineering, Biomedical
Andreas Stylianou, Chrysovalantis Voutouri, Fotios Mpekris, Triantafyllos Stylianopoulos
Summary: Cancer progression is closely associated with changes in the tumor microenvironment (TME) structure and mechanical properties. Desmoplasia, mainly caused by collagen overproduction, leads to tumor stiffness and hinders drug delivery. Understanding the mechanisms involved in desmoplasia and identifying nanomechanical and collagen-based properties can lead to the development of diagnostic and prognostic biomarkers. In this study, in vitro experiments using pancreatic cell lines and orthotopic tumor models demonstrated that invasive cells are softer with elongated shapes and aligned stress fibers. The study also found distinct nanomechanical and collagen-based optical properties in pancreatic cancer, which can be potential biomarkers for monitoring tumor progression and treatment outcomes.
ANNALS OF BIOMEDICAL ENGINEERING
(2023)
Article
Orthopedics
Bo Bregenhof, Per Aagaard, Nis Nissen, Mark W. Creaby, Jonas Bloch Thorlund, Carsten Jensen, Trine Torfing, Anders Holsgaard-Larsen
Summary: For patients with persistent hamstring strength deficits after ACL reconstruction, 12 weeks of supervised progressive strength training was found to be more effective than low-intensity home-based exercises for improving maximal knee flexor muscle strength and some patient-reported outcomes.
JOURNAL OF ORTHOPAEDIC & SPORTS PHYSICAL THERAPY
(2023)
Article
Cell Biology
Larissa Sinkam, Iris Boraschi-Diaz, Rene B. Svensson, Michael Kjaer, Svetlana V. Komarova, Raynald Bergeron, Frank Rauch, Louis-Nicolas Veilleux
Summary: The purpose of this study was to assess the tendon properties of Col1a1(Jrt/+) mice, especially in the context of a collagen type I mutation. The results showed that the FDL tendons of Col1a1(Jrt/+) mice had smaller width and thickness, smaller cross-sectional area, and reduced mechanical properties compared to wild-type mice. However, the material properties of the tendons were seemingly normal. It remains unclear whether the tendon phenotype in Col1a1(Jrt/+) mice is due to muscle weakness, the direct effect of the Col1a1 mutation, or a combination of both.
CONNECTIVE TISSUE RESEARCH
(2023)
Article
Cell & Tissue Engineering
Yoshifumi Tsuchiya, Rene B. Svensson, Ching-Yan Chloe Yeung, Peter Schjerling, Michael Kjaer
Summary: Skeletal muscle has adaptability and regenerative potential due to muscle stem cell activity. The interplay between skeletal muscle and adjacent tendon tissue has not been fully investigated. In this study, we found that factors released by mechanically loaded tendon constructs stimulated myotube formation in human-derived myoblasts. These results suggest the importance of mechanical loading in the signaling interplay between skeletal muscle and tendon tissue for musculoskeletal tissue development and regeneration in humans.
TISSUE ENGINEERING PART A
(2023)
Article
Hematology
Joaquin Calatayud, Daniel C. Ogrezeanu, Juan J. Carrasco, Eduardo Martinez-Valdes, Sofia Perez-Alenda, Carlos Cruz-Montecinos, Lars L. Andersen, Per Aagaard, Luis Suso-Marti, Jose Casana
Summary: This study aimed to compare the safety, feasibility, and neuromuscular activity of low-load resistance exercise with/without blood flow restriction (BFR) in people with severe hemophilia. The results showed that BFR did not cause pain increases or adverse events, and there were no significant changes in neuromuscular activity. Therefore, it is safe and feasible for these patients to perform exercise with low load and appropriate BFR.
EUROPEAN JOURNAL OF HAEMATOLOGY
(2023)
Article
Physiology
Rikke Hoeffner, Rene B. Svensson, Franciele Dietrich-Zagonel, Daniel Schefte, Michael Kjaer, Pernilla Eliasson, S. Peter Magnusson
Summary: Permanent loss of muscle function after Achilles tendon rupture may be due to tendon elongation and accompanying muscle shortening. In rats, Achilles tendon transection resulted in increased tendon length, decreased muscle mass and length, and reduced serial sarcomere number, regardless of suturing. These changes led to an overshoot lengthening of the sarcomeres.
JOURNAL OF APPLIED PHYSIOLOGY
(2023)
Article
Physiology
Tobias Goetschi, Victoria Held, Gianna Klucker, Barbara Niederoest, Per Aagaard, Joerg Spoerri, Fabian S. Passini, Jess G. Snedeker
Summary: Prolonged periods of increased physical demands can cause both positive and negative adaptations in tendons, depending on the underlying mechanisms. The PIEZO1 ion channel has been implicated in tendon mechanotransduction and the E756del gain-of-function variant has been linked to improved jumping performance. This study found that carrying the E756del gene variant was associated with increased patellar tendon stiffness in humans, but there was no correlation between tendon stiffness and jumping performance.
JOURNAL OF APPLIED PHYSIOLOGY
(2023)
Article
Cell Biology
Anders Karlsen, Ching-Yan Chloe Yeung, Peter Schjerling, Linda Denz, Christian Hoegsbjerg, Jens R. Jakobsen, Michael R. Krogsgaard, Manuel Koch, Stefano Schiaffino, Michael Kjaer, Abigail L. Mackey
Summary: Through single-nucleus RNA sequencing, we identified distinct clusters of myonuclei in the myotendinous junction (MTJ) of humans, characterized by different gene expression profiles and fiber types, which has important implications for understanding the specialization of the MTJ.
JOURNAL OF CELL SCIENCE
(2023)
Article
Neurosciences
Ching-Yan Chloe Yeung, Rene B. Svensson, Kateryna Yurchenko, Nikolaj M. Malmgaard-Clausen, Ida Tryggedsson, Marius Lendal, Anja Jokipii-Utzon, Jens L. Olesen, Yinhui Lu, Karl E. Kadler, Peter Schjerling, Michael Kjaer
Summary: By analyzing samples from healthy individuals, researchers found that the gene expression in human tendon tissue exhibited day-to-night changes, with a reduction in collagen I expression during the night. However, chronic tendinopathy patients showed fewer differential gene expressions. This indicates the presence of a conserved circadian clock in healthy human patellar tendons.
JOURNAL OF PHYSIOLOGY-LONDON
(2023)
Article
Sport Sciences
Anne-Sofie Agergaard, Jonathan D. Comins, Volkert Siersma, Nikolaj M. Malmgaard-Clausen, Christian Couppe, Mikkel H. Hjortshoej, Jens L. Olesen, S. Peter Magnusson
Summary: The current study aimed to assess the psychometric properties of the Victorian Institute of Sports Assessment-patellar tendinopathy (VISA-P) questionnaire. The results showed that the VISA-P did not fit a unidimensional model, yielded at best a 3-factor model, and exhibited differential item functioning (DIF) across healthy subjects versus people with patellar tendinopathy. Therefore, a new PROM for patellar tendinopathy should be developed and appropriately validated.
TRANSLATIONAL SPORTS MEDICINE
(2023)
Review
Physiology
M. H. Hjortshoej, P. Aagaard, C. D. Storgaard, H. Juneja, J. Lundbye-Jensen, S. P. Magnusson, C. Couppe
Summary: This study evaluated the hormonal, immune, and oxidative stress responses in healthy adults following low-load blood-flow restricted resistance exercise (LL-BFRRE) and conventional free-flow resistance exercise (FFRE). The results showed that LL-BFRRE induced higher hormone and immune responses compared to FFRE, and had attenuated oxidative stress responses compared to HL-FFRE.
Article
Sport Sciences
Louise B. Nielsen, Rene B. Svensson, Niels U. Fredskild, Kenneth H. Mertz, S. Peter Magnusson, Michael Kjaer, Monika L. Bayer
Summary: This study aimed to investigate the effects of a muscle strain injury in the gastrocnemius muscle on muscle fascicle length, pennation angle, and the morphology of the deep aponeurosis at rest and during muscle contraction. Electromyography (EMG) was also used to measure muscle activity during a unilateral heel rise.
SCANDINAVIAN JOURNAL OF MEDICINE & SCIENCE IN SPORTS
(2023)
Article
Cell Biology
Grith Hojfeldt, Trent Sorenson, Alana Gonzales, Michael Kjaer, Jesper L. Andersen, Abigail L. Mackey
Summary: This study aimed to systematically investigate myofibre branching and fibre type in human skeletal muscle undergoing adult regenerative myogenesis. The findings suggest that myofibre branching is more likely to be fusion of myotubes, explained by incomplete regeneration after necrosis-inducing event.
Article
Biophysics
Jon Skovgaard Jensen, Anders Holsgaard-Larsen, Anders Stengaard Sorensen, Per Aagaard, Jens Bojsen-Moller
Summary: This study investigates the biomechanical effects of robot-assisted body weight unloading (BWU) on gait patterns in healthy young adults. The results show that dynamic robot-assisted BWU enables reduced kinetic requirements without distorting biomechanically normal gait patterns during overground walking.
JOURNAL OF BIOMECHANICS
(2024)
