Cation behavior at an artificial cell interface: binding distinguished by ion hydration energetics and size

2008 ◽  
pp. 948 ◽  
Author(s):  
Alice Merca ◽  
Hartmut Bögge ◽  
Marc Schmidtmann ◽  
Yunshan Zhou ◽  
Erhard T. K. Haupt ◽  
...  
2019 ◽  
Vol 16 (159) ◽  
pp. 20190299
Author(s):  
Ian T. Hoffecker ◽  
Yusuke Arima ◽  
Hiroo Iwata

Adhesive interactions between cells play an integral role in development, differentiation and regeneration. Existing methods for controlling cell–cell cohesion and adhesion by manipulating protein expression are constrained by biological interdependencies, e.g. coupling of cadherins to actomyosin force-feedback mechanisms. We use oligonucleotides conjugated to PEGylated lipid anchors (ssDNAPEGDPPE) to introduce artificial cell–cell adhesion that is largely decoupled from the internal cytoskeleton. We describe cell–cell doublets with a mechanical model based on isotropic, elastic deformation of spheres to estimate the adhesion at the cell–cell interface. Physical manipulation of adhesion by modulating the PEG-lipid to ssDNAPEGDPPE ratio, and conversely treating with actin-depolymerizing cytochalasin D, resulted in decreases and increases in doublet contact area, respectively. Our data are relevant to the ongoing discussion over mechanisms of tissue surface tension and in agreement with models based on opposing cortical and cohesive forces. PEG-lipid modulation of doublet geometries resulted in a well-defined curve indicating continuity, enabling prescriptive calibration for controlling doublet geometry. Our study demonstrates tuning of basic doublet adhesion, laying the foundation for more complex multicellular adhesion control independent of protein expression.


2019 ◽  
Author(s):  
Ian T. Hoffecker ◽  
Yusuke Arima ◽  
Hiroo Iwata

AbstractCohesive interactions between cells play an integral role in development, differentiation, and regeneration. Existing methods for controlling cell-cell cohesion by manipulating protein expression are constrained by biological interdependencies, e.g. coupling of cadherins to actomyosin force-feedback mechanisms. We use oligonucleotides conjugated to PEGylated lipid anchors (ssDNAPEGDPPE) to introduce artificial cell-cell cohesion that is largely decoupled from the internal cytoskeleton. We describe cell-cell doublets with a mechanical model based on isotropic, elastic deformation of spheres to estimate the cohesion at the cell-cell interface. Physical manipulation of cohesion by modulating PEG-lipid to ssDNAPEGDPPE ratio, and conversely treatment with actin-depolymerizing cytochalsin-D, resulted respectively in decreases and increases in doublet contact area. Our data are relevant to the ongoing discussion over mechanisms of tissue surface tension and in agreement with models based on opposing cortical and cohesive forces. PEG-lipid modulation of doublet geometries resulted in a well-defined curve indicating continuity, enabling prescriptive calibration for controlling doublet geometry. Our study demonstrates tuning of basic doublet cohesion, laying the foundation for more complex multicellular cohesion control independent of protein expression.


Author(s):  
Richard Montione ◽  
Muhammad Ashraf

Osmolarity of a fixative vehicle has long been known to have an effect on the tissue preservation. An increase in tissue osmolarity occurs in ischemia-damaged tissue and affects the morphology. In this study, we examined cellular changes in ischemic rat myocardium induced by varying fixative toxicity.Rats were sacrificed by decapitation and the hearts immediately removed and retrogradily perfused through the aorta with anoxic Kurbs-Henseleit medium. Hearts were then placed in a bag with a small amount of medium at 37°C for 90 minutes. Hearts were perfusion-fixed using 2% glutaraldehyde in 0.1 M cacodylate buffer pH -7.3 at three osmolarities. The isotonic buffer was adjusted to 311 mOsm/kg using D-manitol. Hypertonic buffers were adjusted to 375 and 400 mOsm/kg. One-half hour after perfusion fixation, the hearts were sliced and cut into small blocks and allowed to fix overnight at 4°C. Blocks were post fixed in osmium, en bloc stained in uranyl acetate, dehydrated in ethanol and embedded in Spurr medium.


ACS Omega ◽  
2019 ◽  
Vol 4 (7) ◽  
pp. 12727-12735 ◽  
Author(s):  
Jiang Ni ◽  
Ying Sun ◽  
Jinfang Song ◽  
Yiqing Zhao ◽  
Qiufang Gao ◽  
...  

Nanoscale ◽  
2020 ◽  
Vol 12 (18) ◽  
pp. 10189-10195 ◽  
Author(s):  
Xin Zhao ◽  
Dongyang Tang ◽  
Ying Wu ◽  
Shaoqing Chen ◽  
Cheng Wang

The artifical cell system for the gene therapy of cancer might be a promising approach for the reversal of neoplastic progress of cancer cells.


Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 223
Author(s):  
Boying Xu ◽  
Jinquan Ding ◽  
Jian Xu ◽  
Tetsuya Yomo

(1) Background: giant vesicles (GVs) are widely employed as models for studying physicochemical properties of bio-membranes and artificial cell construction due to their similarities to natural cell membranes. Considering the critical roles of GVs, various methods have been developed to prepare them. Notably, the water-in-oil (w/o) inverted emulsion-transfer method is reported to be the most promising, owning to the relatively higher productivity and better encapsulation efficiency of biomolecules. Previously, we successfully established an improved approach to acquire detailed information of 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)-derived GVs with imaging flow cytometry (IFC); (2) Methods: we prepared GVs with different lipid compositions, including phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), and PC/PE mixtures by w/o inverted emulsion methods. We comprehensively compared the yield, purity, size, and encapsulation efficiency of the resulting vesicles; (3) Results: the relatively higher productivities of GVs could be obtained from POPC, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE), DOPC: DLPE (7:3), and POPC: DLPE (6:4) pools. Furthermore, we also demonstrate that these GVs are stable during long term preservation in 4 °C. (4) Conclusions: our results will be useful for the analytical study of GVs and GV-based applications.


Author(s):  
Raheel Ahmad ◽  
Christin Kleineberg ◽  
Vahid Nasirimarekani ◽  
Yu-Jung Su ◽  
Samira Goli Pozveh ◽  
...  

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