scholarly journals Click by Click Microporous Annealed Particle (MAP) Scaffolds

2019 ◽  
Author(s):  
Nicole J. Darling ◽  
Weixian Xi ◽  
Elias Sideris ◽  
Alexa Anderson ◽  
Cassie Pong ◽  
...  
Keyword(s):  
Tissue Repair ◽  
Maximum Stress ◽  
Porous Scaffold ◽  
Click Reaction ◽  
Dermal Fibroblasts ◽  
Hydrogel Microparticles ◽  
Assembly Method ◽  
Key Issues

AbstractMacroporous scaffolds are being increasingly used in regenerative medicine and tissue repair. While our recently developed microporous annealed particle (MAP) scaffolds have overcome issues with injectability and in situ hydrogel formation, limitations with respect to tunability to be able to manipulate hydrogel strength and rigidity for broad applications still exist. To address these key issues, here we synthesized hydrogel microparticles (HMPs) of hyaluronic acid (HA) using the thiol-norbornene click reaction and then subsequently annealed HMPs into a porous scaffold using the tetrazine-norbornene click reaction. This assembly method allowed for straightforward tuning of bulk scaffold rigidity by varying the tetrazine to norbornene ratio, with increasing tetrazine resulting in increasing scaffold storage modulus, Young’s modulus, and maximum stress. These changes were independent of void fraction. Further incorporation of human dermal fibroblasts (HDFs) throughout the porous scaffold revealed the biocompatibility of this annealing strategy as well as differences in proliferation and cell-occupied volume. Finally, injection of porous HA-Tet MAP scaffolds into an ischemic stroke model showed this chemistry is biocompatible in vivo with reduced levels of inflammation and astrogliosis as previously demonstrated for other crosslinking chemistries.

scholarly journals Deciphering the in vivo Dynamic Proteomics of Mesenchymal Stem Cells in Critical Limb Ischemia

2021 ◽  
Vol 9 ◽  
Author(s):  
Yipeng Du ◽  
Xiaoting Li ◽  
Wenying Yan ◽  
Zhaohua Zeng ◽  
Dunzheng Han ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Protein Synthesis ◽  
Critical Limb Ischemia ◽  
Click Reaction ◽  
Limb Ischemia ◽  
Trna Synthetase ◽  
Doppler Imaging

ObjectiveRegenerative therapy using mesenchymal stem cells (MSC) is a promising therapeutic method for critical limb ischemia (CLI). To understand how the cells are involved in the regenerative process of limb ischemia locally, we proposed a metabolic protein labeling method to label cell proteomes in situ and then decipher the proteome dynamics of MSCs in ischemic hind limb.Methods and ResultsIn this study, we overexpressed mutant methionyl-tRNA synthetase (MetRS), which could utilize azidonorleucine (ANL) instead of methionine (Met) during protein synthesis in MSCs. Fluorescent non-canonical amino-acid tagging (FUNCAT) was performed to detect the utilization of ANL in mutant MSCs. Mice with hindlimb ischemia (HLI) or Sham surgery were treated with MetRSmut MSCs or PBS, followed by i.p. administration of ANL at days 0, 2 6, and 13 after surgery. FUNCAT was also performed in hindlimb tissue sections to demonstrate the incorporation of ANL in transplanted cells in situ. At days 1, 3, 7, and 14 after the surgery, laser doppler imaging were performed to detect the blood reperfusion of ischemic limbs. Ischemic tissues were also collected at these four time points for histological analysis including HE staining and vessel staining, and processed for click reaction based protein enrichment followed by mass spectrometry and bioinformatics analysis. The MetRSmut MSCs showed strong green signal in cell culture and in HLI muscles as well, indicating efficient incorporation of ANL in nascent protein synthesis. By 14 days post-treatment, MSCs significantly increased blood reperfusion and vessel density, while reducing inflammation in HLI model compared to PBS. Proteins enriched by click reaction were distinctive in the HLI group vs. the Sham group. 34, 31, 49, and 26 proteins were significantly up-regulated whereas 28, 32, 62, and 27 proteins were significantly down-regulated in HLI vs. Sham at days 1, 3, 7, and 14, respectively. The differentially expressed proteins were more pronounced in the pathways of apoptosis and energy metabolism.ConclusionIn conclusion, mutant MetRS allows efficient and specific identification of dynamic cell proteomics in situ, which reflect the functions and adaptive changes of MSCs that may be leveraged to understand and improve stem cell therapy in critical limb ischemia.

scholarly journals In vivo sequestration of innate small molecules to promote bone healing

2019 ◽  
Author(s):  
Yuze Zeng ◽  
Yu-Ru V. Shih ◽  
Gurpreet S. Baht ◽  
Shyni Varghese
Keyword(s):  
Small Molecules ◽  
Human Body ◽  
Tissue Repair ◽  
Physiological Level ◽  
Extracellular Adenosine ◽  
Injury Site ◽  
Synthetic Biomaterial ◽  
Repair Mechanisms

AbstractApproaches that enable innate repair mechanisms hold great potential for tissue repair. Herein, we describe biomaterial-assisted sequestration of small molecules to localize pro-regenerative signaling at the injury site. Specifically, we designed a synthetic biomaterial containing boronate molecules to sequester adenosine, a small molecule ubiquitously present in the human body. The biomaterial-assisted sequestration of adenosine leverages the transient surge of extracellular adenosine following injury to prolong local adenosine signaling. We demonstrated that implantation of the biomaterial patch following injury establishes an in-situ stockpile of adenosine, resulting in accelerated healing by promoting both osteoblastogenesis and angiogenesis. The adenosine content within the patch recedes to the physiological level as the tissue regenerates. In addition to sequestering endogenous adenosine, the biomaterial is also able to deliver exogenous adenosine to the site of injury, offering a versatile solution to utilizing adenosine as a potential therapeutic for tissue repair.

scholarly journals A dynamic spectrum of monocytes arising from the in situ reprogramming of CCR2+ monocytes at a site of sterile injury

2015 ◽  
Vol 212 (4) ◽  
pp. 447-456 ◽  
Author(s):  
Daniela Dal-Secco ◽  
Jing Wang ◽  
Zhutian Zeng ◽  
Elzbieta Kolaczkowska ◽  
Connie H.Y. Wong ◽  
...  
Keyword(s):  
Wound Healing ◽  
Tissue Repair ◽  
Hepatic Injury ◽  
Dynamic Spectrum ◽  
Fluorescent Reporters ◽  
Injured Area ◽  
A Site ◽  
Local Cytokine

Monocytes are recruited from the blood to sites of inflammation, where they contribute to wound healing and tissue repair. There are at least two subsets of monocytes: classical or proinflammatory (CCR2hiCX3CR1low) and nonclassical, patrolling, or alternative (CCR2lowCX3CR1hi) monocytes. Using spinning-disk confocal intravital microscopy and mice with fluorescent reporters for each of these subsets, we were able to track the dynamic spectrum of monocytes that enter a site of sterile hepatic injury in vivo. We observed that the CCR2hiCX3CR1low monocytes were recruited early and persisted for at least 48 h, forming a ringlike structure around the injured area. These monocytes transitioned, in situ, from CCR2hiCx3CR1low to CX3CR1hiCCR2low within the ringlike structure and then entered the injury site. This phenotypic conversion was essential for optimal repair. These results demonstrate a local, cytokine driven reprogramming of classic, proinflammatory monocytes into nonclassical or alternative monocytes to facilitate proper wound-healing.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Three-Dimensional Subcellular Organization of Hepatocytes in Intact Liver: Simultaneous Visualization of Cytoskeletal and Membrane Markers by Confocal Microscopy

1996 ◽  
Vol 54 ◽  
pp. 288-289
Author(s):  
Greg V. Martin ◽  
Ann L. Hubbard
Keyword(s):  
Three Dimensional ◽  
Integral Membrane Proteins ◽  
Polarized Secretion ◽  
Microscope Images ◽  
Computer Aided ◽  
Intracellular Organelles ◽  
Cytoskeletal Elements ◽  
Simultaneous Visualization

The microtubule (MT) cytoskeleton is necessary for many of the polarized functions of hepatocytes. Among the functions dependent on the MT-based cytoskeleton are polarized secretion of proteins, delivery of endocytosed material to lysosomes, and transcytosis of integral plasma membrane (PM) proteins. Although microtubules have been shown to be crucial to the establishment and maintenance of functional and structural polarization in the hepatocyte, little is known about the architecture of the hepatocyte MT cytoskeleton in vivo, particularly with regard to its relationship to PM domains and membranous organelles. Using an in situ extraction technique that preserves both microtubules and cellular membranes, we have developed a protocol for immunofluorescent co-localization of cytoskeletal elements and integral membrane proteins within 20 µm cryosections of fixed rat liver. Computer-aided 3D reconstruction of multi-spectral confocal microscope images was used to visualize the spatial relationships among the MT cytoskeleton, PM domains and intracellular organelles.

Evaluation of Structure-Controlled Silk Fibroin Coatings for Orthopedic Infection and In-Situ Osteogenesis: In Vitro and In Vivo

2020 ◽  
Author(s):  
Wenhao Zhou ◽  
Teng Zhang ◽  
Jianglong Yan ◽  
QiYao Li ◽  
Panpan Xiong ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Orthopedic Infection

scholarly journals Ferromagnetic soft catheter robots for minimally invasive bioprinting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cheng Zhou ◽  
Youzhou Yang ◽  
Jiaxin Wang ◽  
Qingyang Wu ◽  
Zhuozhi Gu ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
The Body ◽  
Magnetic Actuation ◽  
Internal Organs ◽  
Planar Surfaces ◽  
Reinforced Polymer ◽  
Direct Fabrication ◽  
Digitally Controlled

AbstractIn vivo bioprinting has recently emerged as a direct fabrication technique to create artificial tissues and medical devices on target sites within the body, enabling advanced clinical strategies. However, existing in vivo bioprinting methods are often limited to applications near the skin or require open surgery for printing on internal organs. Here, we report a ferromagnetic soft catheter robot (FSCR) system capable of in situ computer-controlled bioprinting in a minimally invasive manner based on magnetic actuation. The FSCR is designed by dispersing ferromagnetic particles in a fiber-reinforced polymer matrix. This design results in stable ink extrusion and allows for printing various materials with different rheological properties and functionalities. A superimposed magnetic field drives the FSCR to achieve digitally controlled printing with high accuracy. We demonstrate printing multiple patterns on planar surfaces, and considering the non-planar surface of natural organs, we then develop an in situ printing strategy for curved surfaces and demonstrate minimally invasive in vivo bioprinting of hydrogels in a rat model. Our catheter robot will permit intelligent and minimally invasive bio-fabrication.

Effects of in vitro low oxygen tension preconditioning of buccal fat pad stem cells on in Vivo articular cartilage tissue repair

Life Sciences ◽  
2021 ◽  
pp. 119728
Author(s):  
Fatemeh Dehghani Nazhvani ◽  
Leila Mohammadi Amirabad ◽  
Arezo Azari ◽  
Hamid Namazi ◽  
Simzar Hosseinzadeh ◽  
...  
Keyword(s):  
Stem Cells ◽  
Articular Cartilage ◽  
Tissue Repair ◽  
Cartilage Tissue ◽  
Low Oxygen ◽  
Fat Pad ◽  
Buccal Fat Pad ◽  
Low Oxygen Tension
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