Probing the mechanical properties of Drosophila embryo ephitelial cells in vivo by laser nanodissection

Abstract Rap1 belongs to the highly conserved Ras subfamily of small GTPases. In Drosophila, Rap1 plays a critical role in many different morphogenetic processes, but the molecular mechanisms executing its function are unknown. Here, we demonstrate that Canoe (Cno), the Drosophila homolog of mammalian junctional protein AF-6, acts as an effector of Rap1 in vivo. Cno binds to the activated form of Rap1 in a yeast two-hybrid assay, the two molecules colocalize to the adherens junction, and they display very similar phenotypes in embryonic dorsal closure (DC), a process that relies on the elongation and migration of epithelial cell sheets. Genetic interaction experiments show that Rap1 and Cno act in the same molecular pathway during DC and that the function of both molecules in DC depends on their ability to interact. We further show that Rap1 acts upstream of Cno, but that Rap1, unlike Cno, is not involved in the stimulation of JNK pathway activity, indicating that Cno has both a Rap1-dependent and a Rap1-independent function in the DC process.

Download Full-text

Concomitant control of mechanical properties and degradation in resorbable elastomer-like materials using stereochemistry and stoichiometry for soft tissue engineering

Nature Communications ◽

10.1038/s41467-020-20610-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Mary Beth Wandel ◽

Craig A. Bell ◽

Jiayi Yu ◽

Maria C. Arno ◽

Nathan Z. Dreger ◽

...

Keyword(s):

Mechanical Properties ◽

Drug Delivery ◽

Soft Tissue ◽

Tissue Regeneration ◽

Biological Tissues ◽

Soft Tissue Regeneration ◽

Soft Tissue Engineering ◽

Degradation Properties ◽

Enhance Cell Adhesion

AbstractComplex biological tissues are highly viscoelastic and dynamic. Efforts to repair or replace cartilage, tendon, muscle, and vasculature using materials that facilitate repair and regeneration have been ongoing for decades. However, materials that possess the mechanical, chemical, and resorption characteristics necessary to recapitulate these tissues have been difficult to mimic using synthetic resorbable biomaterials. Herein, we report a series of resorbable elastomer-like materials that are compositionally identical and possess varying ratios of cis:trans double bonds in the backbone. These features afford concomitant control over the mechanical and surface eroding degradation properties of these materials. We show the materials can be functionalized post-polymerization with bioactive species and enhance cell adhesion. Furthermore, an in vivo rat model demonstrates that degradation and resorption are dependent on succinate stoichiometry in the elastomers and the results show limited inflammation highlighting their potential for use in soft tissue regeneration and drug delivery.

Download Full-text

Injectable non-leaching tissue-mimetic bottlebrush elastomers as an advanced platform for reconstructive surgery

Nature Communications ◽

10.1038/s41467-021-23962-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Erfan Dashtimoghadam ◽

Farahnaz Fahimipour ◽

Andrew N. Keith ◽

Foad Vashahi ◽

Pavel Popryadukhin ◽

...

Keyword(s):

Mechanical Properties ◽

Reconstructive Surgery ◽

Biomedical Applications ◽

The Body ◽

Surrounding Tissue ◽

Curing Time ◽

Materials Used ◽

Significant Health

AbstractCurrent materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.

Download Full-text

Zn-Containing Membranes for Guided Bone Regeneration in Dentistry

Polymers ◽

10.3390/polym13111797 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1797

Author(s):

Manuel Toledano ◽

Marta Vallecillo-Rivas ◽

María T. Osorio ◽

Esther Muñoz-Soto ◽

Manuel Toledano-Osorio ◽

...

Keyword(s):

Mechanical Properties ◽

Bone Regeneration ◽

Bone Healing ◽

Bone Repair ◽

Complex Modulus ◽

Bacterial Colonization ◽

Guided Bone Regeneration ◽

M2 Macrophage

Barrier membranes are employed in guided bone regeneration (GBR) to facilitate bone in-growth. A bioactive and biomimetic Zn-doped membrane with the ability to participate in bone healing and regeneration is necessary. The aim of the present study is to state the effect of doping the membranes for GBR with zinc compounds in the improvement of bone regeneration. A literature search was conducted using electronic databases, such as PubMed, MEDLINE, DIMDI, Embase, Scopus and Web of Science. A narrative exploratory review was undertaken, focusing on the antibacterial effects, physicochemical and biological properties of Zn-loaded membranes. Bioactivity, bone formation and cytotoxicity were analyzed. Microstructure and mechanical properties of these membranes were also determined. Zn-doped membranes have inhibited in vivo and in vitro bacterial colonization. Zn-alloy and Zn-doped membranes attained good biocompatibility and were found to be non-toxic to cells. The Zn-doped matrices showed feasible mechanical properties, such as flexibility, strength, complex modulus and tan delta. Zn incorporation in polymeric membranes provided the highest regenerative efficiency for bone healing in experimental animals, potentiating osteogenesis, angiogenesis, biological activity and a balanced remodeling. Zn-loaded membranes doped with SiO2 nanoparticles have performed as bioactive modulators provoking an M2 macrophage increase and are a potential biomaterial for promoting bone repair. Zn-doped membranes have promoted pro-healing phenotypes.

Download Full-text

Fibronectin Adsorption on Electrospun Synthetic Vascular Grafts Attracts Endothelial Progenitor Cells and Promotes Endothelialization in Dynamic In Vitro Culture

Cells ◽

10.3390/cells9030778 ◽

2020 ◽

Vol 9 (3) ◽

pp. 778 ◽

Cited By ~ 4

Author(s):

Ruben Daum ◽

Dmitri Visser ◽

Constanze Wild ◽

Larysa Kutuzova ◽

Maria Schneider ◽

...

Keyword(s):

Mechanical Properties ◽

Cell Activation ◽

Vascular Endothelial Cells ◽

Endothelial Progenitor ◽

Advanced Therapy Medicinal Product ◽

Endothelial Colony Forming Cells ◽

Advanced Therapy ◽

Custom Made

Appropriate mechanical properties and fast endothelialization of synthetic grafts are key to ensure long-term functionality of implants. We used a newly developed biostable polyurethane elastomer (TPCU) to engineer electrospun vascular scaffolds with promising mechanical properties (E-modulus: 4.8 ± 0.6 MPa, burst pressure: 3326 ± 78 mmHg), which were biofunctionalized with fibronectin (FN) and decorin (DCN). Neither uncoated nor biofunctionalized TPCU scaffolds induced major adverse immune responses except for minor signs of polymorph nuclear cell activation. The in vivo endothelial progenitor cell homing potential of the biofunctionalized scaffolds was simulated in vitro by attracting endothelial colony-forming cells (ECFCs). Although DCN coating did attract ECFCs in combination with FN (FN + DCN), DCN-coated TPCU scaffolds showed a cell-repellent effect in the absence of FN. In a tissue-engineering approach, the electrospun and biofunctionalized tubular grafts were cultured with primary-isolated vascular endothelial cells in a custom-made bioreactor under dynamic conditions with the aim to engineer an advanced therapy medicinal product. Both FN and FN + DCN functionalization supported the formation of a confluent and functional endothelial layer.

Download Full-text

Blood pressure regulation V: in vivo mechanical properties of precapillary vessels as affected by long-term pressure loading and unloading

European Journal of Applied Physiology ◽

10.1007/s00421-013-2758-9 ◽

2013 ◽

Vol 114 (3) ◽

pp. 499-509 ◽

Cited By ~ 7

Author(s):

Ola Eiken ◽

Igor B. Mekjavic ◽

Roger Kölegård

Keyword(s):

Mechanical Properties ◽

Blood Pressure ◽

Blood Pressure Regulation ◽

Pressure Regulation ◽

Pressure Loading ◽

Loading And Unloading

Download Full-text

Gender Difference in Architectural and Mechanical Properties of Medial Gastrocnemius–Achilles Tendon Unit In Vivo

Life ◽

10.3390/life11060569 ◽

2021 ◽

Vol 11 (6) ◽

pp. 569

Author(s):

Liqin Deng ◽

Xini Zhang ◽

Songlin Xiao ◽

Baofeng Wang ◽

Weijie Fu

Keyword(s):

Mechanical Properties ◽

Gender Differences ◽

Gender Difference ◽

Achilles Tendon ◽

Medial Gastrocnemius ◽

Regular Exercise ◽

Training Experience ◽

Exercise Habits ◽

Vertical Stiffness

This study aims to explore whether gender differences exist in the architectural and mechanical properties of the medial gastrocnemius–Achilles tendon unit (gMTU) in vivo. Thirty-six healthy male and female adults without training experience and regular exercise habits were recruited. The architectural and mechanical properties of the gMTU were measured via an ultrasonography system and MyotonPRO, respectively. Independent t-tests were utilized to quantify the gender difference in the architectural and mechanical properties of the gMTU. In terms of architectural properties, the medial gastrocnemius (MG)’s pennation angle and thickness were greater in males than in females, whereas no substantial gender difference was observed in the MG’s fascicle length; the males possessed Achilles tendons (ATs) with a longer length and a greater cross-sectional area than females. In terms of mechanical properties, the MG’s vertical stiffness was lower and the MG’s logarithmic decrement was greater in females than in males. Both genders had no remarkable difference in the AT’s vertical stiffness and logarithmic decrement. Gender differences of individuals without training experience and regular exercise habits exist in the architectural and mechanical properties of the gMTU in vivo. The MG’s force-producing capacities, ankle torque, mechanical efficiency and peak power were higher in males than in females. The load-resisting capacities of AT were greater and the MG strain was lesser in males than in females. These findings suggest that males have better physical fitness, speed and performance in power-based sports events than females from the perspective of morphology and biomechanics.

Download Full-text

Mechanical Properties of Arteries in Vivo

Circulation Research ◽

10.1161/01.res.8.3.622 ◽

1960 ◽

Vol 8 (3) ◽

pp. 622-639 ◽

Cited By ~ 461

Author(s):

LYSLE H. PETERSON ◽

RODERICK E. JENSEN ◽

JOHN PARNELL

Keyword(s):

Mechanical Properties

Download Full-text

In Vitro and In Vivo Degradation, Mechanical Properties, and Histocompatibility of Weft-Knitted Silk Mesh-Like Grafts

Journal of Biomaterials and Tissue Engineering ◽

10.1166/jbt.2022.2911 ◽

2022 ◽

Vol 12 (2) ◽

pp. 411-416

Author(s):

Liang Tang ◽

Si-Yu Zhao ◽

Ya-Dong Yang ◽

Geng Yang ◽

Wen-Yuan Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Simulated Body Fluid ◽

Body Fluid ◽

Degradation Rate ◽

Maximum Load ◽

Artificial Ligament ◽

In Vivo Degradation

To investigate the degradation, mechanical properties, and histocompatibility of weft-knitted silk mesh-like grafts, we carried out the In Vitro and In Vivo silk grafts degradation assay. The In Vitro degradation experiment was performed by immersing the silk grafts in simulated body fluid for 1 year, and the results showed that the degradation rate of the silk mesh-like grafts was very slow, and there were few changes in the mechanical properties and quality of the silk mesh-like graft. In Vivo degradation assay was taken by implantation of the silk mesh-like grafts into the subcutaneous muscles of rabbits. At 3, 6, and 12 months postoperation, the rate of mass loss was 19.36%, 31.84%, and 58.77%, respectively, and the maximum load was 63.85%, 34.63%, and 10.76%, respectively of that prior to degradation. The results showed that the degradation rate of the silk graft and the loss of mechanical properties In Vivo were faster than the results obtained in the In Vitro experiments. In addition, there were no significant differences in secretion of serum IL-6 and TNF-α between the experimental and normal rabbits (P >0.05), suggesting no obvious inflammatory reaction. The findings suggest that the weft-knitted silk mesh-like grafts have good mechanical properties, histocompatibility, and In Vivo degradation rate, and therefore represent a candidate material for artificial ligament

Download Full-text