scholarly journals Regeneration of partially decellularized tracheal scaffolds in a mouse model of orthotopic tracheal replacement

2021 ◽  
Vol 12 ◽  
pp. 204173142110174
Author(s):  
Lumei Liu ◽  
Sayali Dharmadhikari ◽  
Kimberly M Shontz ◽  
Zheng Hong Tan ◽  
Barak M Spector ◽  
...  
Keyword(s):  
Mouse Model ◽  
Study Endpoint ◽  
Potential Solution ◽  
Orthotopic Implantation ◽  
Chondrocyte Viability ◽  
Force Microscopy ◽  
Atomic Force ◽  
Tracheal Replacement ◽  
Tracheal Collapse

Decellularized tracheal scaffolds offer a potential solution for the repair of long-segment tracheal defects. However, complete decellularization of trachea is complicated by tracheal collapse. We created a partially decellularized tracheal scaffold (DTS) and characterized regeneration in a mouse model of tracheal transplantation. All cell populations except chondrocytes were eliminated from DTS. DTS maintained graft integrity as well as its predominant extracellular matrix (ECM) proteins. We then assessed the performance of DTS in vivo. Grafts formed a functional epithelium by study endpoint (28 days). While initial chondrocyte viability was low, this was found to improve in vivo. We then used atomic force microscopy to quantify micromechanical properties of DTS, demonstrating that orthotopic implantation and graft regeneration lead to the restoration of native tracheal rigidity. We conclude that DTS preserves the cartilage ECM, supports neo-epithelialization, endothelialization and chondrocyte viability, and can serve as a potential solution for long-segment tracheal defects.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

scholarly journals Biomechanics of Neutrophil Tethers

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 515
Author(s):  
Andrea Cugno ◽  
Alex Marki ◽  
Klaus Ley
Keyword(s):  
Cell Activation ◽  
Optical Trap ◽  
Biomechanical Properties ◽  
Force Microscopy ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Microfluidic Flow ◽  
Biomembrane Force Probe ◽  
Membrane Reservoir

Leukocytes, including neutrophils, which are propelled by blood flow, can roll on inflamed endothelium using transient bonds between selectins and their ligands, and integrins and their ligands. When such receptor–ligand bonds last long enough, the leukocyte microvilli become extended and eventually form thin, 20 m long tethers. Tether formation can be observed in blood vessels in vivo and in microfluidic flow chambers. Tethers can also be extracted using micropipette aspiration, biomembrane force probe, optical trap, or atomic force microscopy approaches. Here, we review the biomechanical properties of leukocyte tethers as gleaned from such measurements and discuss the advantages and disadvantages of each approach. We also review and discuss viscoelastic models that describe the dependence of tether formation on time, force, rate of loading, and cell activation. We close by emphasizing the need to combine experimental observations with quantitative models and computer simulations to understand how tether formation is affected by membrane tension, membrane reservoir, and interactions of the membrane with the cytoskeleton.

scholarly journals Silane-Coating Strategy for Titanium Functionalization Does Not Impair Osteogenesis In Vivo

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1814
Author(s):  
Plinio Mendes Senna ◽  
Carlos Fernando de Almeida Barros Mourão ◽  
Rafael Coutinho Mello-Machado ◽  
Kayvon Javid ◽  
Pietro Montemezzi ◽  
...  
Keyword(s):  
Bone Formation ◽  
Photoelectron Spectroscopy ◽  
Titanium Surface ◽  
Rabbit Model ◽  
Biologically Active ◽  
Force Microscopy ◽  
Atomic Force ◽  
Silane Coating ◽  
Titanium Screws

Silane-coating strategy has been used to bind biological compounds to the titanium surface, thereby making implant devices biologically active. However, it has not been determined if the presence of the silane coating itself is biocompatible to osseointegration. The aim of the present study was to evaluate if silane-coating affects bone formation on titanium using a rabbit model. For this, titanium screw implants (3.75 by 6 mm) were hydroxylated in a solution of H2SO4/30% H2O2 for 4 h before silane-coating with 3-aminopropyltriethoxysilane (APTES). A parallel set of titanium screws underwent only the hydroxylation process to present similar acid-etched topography as a control. The presence of the silane on the surface was checked by x-ray photoelectron spectroscopy (XPS), with scanning electron microscopy (SEM) and atomic force microscopy (AFM). A total of 40 titanium screws were implanted in the tibia of ten New Zealand rabbits in order to evaluate bone-to-implant contact (BIC) after 3 weeks and 6 weeks of healing. Silane-coated surface presented higher nitrogen content in the XPS analysis, while micro- and nano-topography of the surface remained unaffected. No difference between the groups was observed after 3 and 6 weeks of healing (p > 0.05, independent t-test), although an increase in BIC occurred over time. These results indicate that silanization of a titanium surface with APTES did not impair the bone formation, indicating that this can be a reliable tool to anchor osteogenic molecules on the surface of implant devices.

Diabetes increases stiffness of live cardiomyocytes measured by atomic force microscopy nanoindentation

2014 ◽  
Vol 307 (10) ◽  
pp. C910-C919 ◽  
Author(s):  
Juan C. Benech ◽  
Nicolás Benech ◽  
Ana I. Zambrana ◽  
Inés Rauschert ◽  
Verónica Bervejillo ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Physiological Condition ◽  
Diabetic Mice ◽  
Cell Nuclei ◽  
Buffer Solution ◽  
Isolated Cardiomyocytes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Myocardial Fibers

Stiffness of live cardiomyocytes isolated from control and diabetic mice was measured using the atomic force microscopy nanoindentation method. Type 1 diabetes was induced in mice by streptozotocin administration. Histological images of myocardium from mice that were diabetic for 3 mo showed disorderly lineup of myocardial cells, irregularly sized cell nuclei, and fragmented and disordered myocardial fibers with interstitial collagen accumulation. Phalloidin-stained cardiomyocytes isolated from diabetic mice showed altered (i.e., more irregular and diffuse) actin filament organization compared with cardiomyocytes from control mice. Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) pump expression was reduced in homogenates obtained from the left ventricle of diabetic animals compared with age-matched controls. The apparent elastic modulus (AEM) for live control or diabetic isolated cardiomyocytes was measured using the atomic force microscopy nanoindentation method in Tyrode buffer solution containing 1.8 mM Ca2+ and 5.4 mM KCl (physiological condition), 100 nM Ca2+ and 5.4 mM KCl (low extracellular Ca2+ condition), or 1.8 mM Ca2+ and 140 mM KCl (contraction condition). In the physiological condition, the mean AEM was 112% higher for live diabetic than control isolated cardiomyocytes (91 ± 14 vs. 43 ± 7 kPa). The AEM was also significantly higher in diabetic than control cardiomyocytes in the low extracellular Ca2+ and contraction conditions. These findings suggest that the material properties of live cardiomyocytes were affected by diabetes, resulting in stiffer cells, which very likely contribute to high diastolic LV stiffness, which has been observed in vivo in some diabetes mellitus patients.

scholarly journals In vivo dynamics of the cortical actin network revealed by fast-scanning atomic force microscopy

Microscopy ◽  
2017 ◽  
Vol 66 (4) ◽  
pp. 272-282 ◽  
Author(s):  
Yanshu Zhang ◽  
Aiko Yoshida ◽  
Nobuaki Sakai ◽  
Yoshitsugu Uekusa ◽  
Masahiro Kumeta ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Actin Network ◽  
Cortical Actin ◽  
Force Microscopy ◽  
Atomic Force

In Vivo Atomic Force Microscopy of Surface Proteins onDeinococcus radiodurans

Langmuir ◽  
2001 ◽  
Vol 17 (9) ◽  
pp. 2624-2628 ◽  
Author(s):  
T. E. Lister ◽  
P. J. Pinhero
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Proteins ◽  
Force Microscopy ◽  
Atomic Force

In vivo nanomechanical imaging of blood-vessel tissues directly in living mammals using atomic force microscopy

2009 ◽  
Vol 95 (1) ◽  
pp. 013704 ◽  
Author(s):  
Youdong Mao ◽  
Quanmei Sun ◽  
Xiufeng Wang ◽  
Qi Ouyang ◽  
Li Han ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Blood Vessel ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Dynamics of cell wall elasticity pattern shapes the cell during yeast mating morphogenesis

Open Biology ◽  
2016 ◽  
Vol 6 (9) ◽  
pp. 160136 ◽  
Author(s):  
Björn Goldenbogen ◽  
Wolfgang Giese ◽  
Marie Hemmen ◽  
Jannis Uhlendorf ◽  
Andreas Herrmann ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Shape ◽  
Experimental Approach ◽  
Time Resolved ◽  
Force Microscopy ◽  
Cell Wall Elasticity ◽  
Atomic Force ◽  
Stiff Material ◽  
Mating Projection

The cell wall defines cell shape and maintains integrity of fungi and plants. When exposed to mating pheromone, Saccharomyces cerevisiae grows a mating projection and alters in morphology from spherical to shmoo form. Although structural and compositional alterations of the cell wall accompany shape transitions, their impact on cell wall elasticity is unknown. In a combined theoretical and experimental approach using finite-element modelling and atomic force microscopy (AFM), we investigated the influence of spatially and temporally varying material properties on mating morphogenesis. Time-resolved elasticity maps of shmooing yeast acquired with AFM in vivo revealed distinct patterns, with soft material at the emerging mating projection and stiff material at the tip. The observed cell wall softening in the protrusion region is necessary for the formation of the characteristic shmoo shape, and results in wider and longer mating projections. The approach is generally applicable to tip-growing fungi and plants cells.

Sign in / Sign up

Export Citation Format

Share Document