“…4H) into the tibialis anterior (TA) muscles of C57BL/6 mice. The paramagnetic Gd(III) chelate produces positive contrast in magnetic resonance imaging (MRI), a technique providing unparalleled spatial resolution in vivo (38). After harvesting, we examined the tissues by macroscopic inspection or MRI of EBDlabeled or Gd(III)-labeled scaffolds.…”
Section: Development Of An Injection Apparatus To Form Aligned Biomimmentioning
Muscle stem cells are a potent cell population dedicated to efficacious skeletal muscle regeneration, but their therapeutic utility is currently limited by mode of delivery. We developed a cell delivery strategy based on a supramolecular liquid crystal formed by peptide amphiphiles (PAs) that encapsulates cells and growth factors within a muscle-like unidirectionally ordered environment of nanofibers. The stiffness of the PA scaffolds, dependent on amino acid sequence, was found to determine the macroscopic degree of cell alignment templated by the nanofibers in vitro. Furthermore, these PA scaffolds support myogenic progenitor cell survival and proliferation and they can be optimized to induce cell differentiation and maturation. We engineered an in vivo delivery system to assemble scaffolds by injection of a PA solution that enabled coalignment of scaffold nanofibers with endogenous myofibers. These scaffolds locally retained growth factors, displayed degradation rates matching the time course of muscle tissue regeneration, and markedly enhanced the engraftment of muscle stem cells in injured and noninjured muscles in mice.biomaterials | scaffold | muscle stem cell | cell delivery | muscle regeneration
“…4H) into the tibialis anterior (TA) muscles of C57BL/6 mice. The paramagnetic Gd(III) chelate produces positive contrast in magnetic resonance imaging (MRI), a technique providing unparalleled spatial resolution in vivo (38). After harvesting, we examined the tissues by macroscopic inspection or MRI of EBDlabeled or Gd(III)-labeled scaffolds.…”
Section: Development Of An Injection Apparatus To Form Aligned Biomimmentioning
Muscle stem cells are a potent cell population dedicated to efficacious skeletal muscle regeneration, but their therapeutic utility is currently limited by mode of delivery. We developed a cell delivery strategy based on a supramolecular liquid crystal formed by peptide amphiphiles (PAs) that encapsulates cells and growth factors within a muscle-like unidirectionally ordered environment of nanofibers. The stiffness of the PA scaffolds, dependent on amino acid sequence, was found to determine the macroscopic degree of cell alignment templated by the nanofibers in vitro. Furthermore, these PA scaffolds support myogenic progenitor cell survival and proliferation and they can be optimized to induce cell differentiation and maturation. We engineered an in vivo delivery system to assemble scaffolds by injection of a PA solution that enabled coalignment of scaffold nanofibers with endogenous myofibers. These scaffolds locally retained growth factors, displayed degradation rates matching the time course of muscle tissue regeneration, and markedly enhanced the engraftment of muscle stem cells in injured and noninjured muscles in mice.biomaterials | scaffold | muscle stem cell | cell delivery | muscle regeneration
“…These agents, which are referred to stimulus-responsive or smart contrast agents, are sensitive to specific fluctuations in the local environment, such as pH, biological metal ion concentration or enzymatic activity, and are capable of reporting on such changes by inducing alterations in the MRI signal [119][120][121][122][123][124]. The change in relaxivity of these agents before and after stimulation is the most important factor in evaluating the efficiency of a stimulus-responsive contrast agent [125].…”
Brain cancer is one of the most lethal and difficult-to-treat cancers because of its physical location and biological barriers. The mainstay of brain cancer treatment is surgical resection, which demands precise imaging for tumor localization and delineation. Thanks to advances in bioimaging, brain cancer can be detected earlier and resected more reliably. Magnetic resonance imaging (MRI) is the most common and preferred method to delineate brain cancer, and a contrast agent is often required to enhance imaging contrast. Dendrimers, a special family of synthetic macromolecules, constitute a particularly appealing platform for constructing MRI contrast agents by virtue of their well-defined three-dimensional structure, tunable nanosize and abundant surface terminals, which allow the accommodation of high payloads and numerous functionalities. Tuning the dendrimer size, branching and surface composition in conjunction with conjugation of MRI functionalities and targeting moieties can alter the relaxivity for MRI, overcome the blood-brain barrier and enhance tumor-specific targeting, hence improving the imaging quality and safety profile for precise and accurate imaging of brain tumors. This short review highlights the recent progress, opportunities and challenges in developing dendrimer-based MRI contrast agents for brain tumor imaging.
“…[137] Generally, non-polarized light is converted in CP light using filters or with more complex systems architectures, [138] which often lead to a loss in brightness.…”
Section: Applications To Organic Light Emission Diodes Technologymentioning
The capability to fully control the chiro‐optical properties of metamaterials has drawn considerable attention due to developments in metamaterial fabrication techniques and a deeper understanding of the light–matter interaction, enabling a number of applications from integrated photonics to life sciences. From simple geometrical studies on single helix shaped metamaterials, both the design complexity and nanofabrication capability are steadily increasing allowing to extend their properties to the visible regime and beyond. In this work, helix‐shaped micro‐ and nanostructures are reviewed, which have the possibility to modulate their optical response in the linear regime at optical frequencies by spatial arrangement or by constitutive material. An overview of different theories describing the general optical operation of chiral media and a discussion on experimental results obtained by the state‐of‐the‐art helix structures realized by different fabrication techniques is provided. Finally, advanced designs for improved functionality envisaged to match practical applications or to enable new optical multifunctionalities are compared. Even if many applications have been envisaged only theoretically, the continuous effort and progress shown by the research community engaged in this field suggests that helical chiral metamaterials could represent a disruptive breakthrough for advanced optical devices.
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