| 1. |
- Amagat, Jordi, et al.
(författare)
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Injectable 2D flexible hydrogel sheets for optoelectrical/biochemical dual stimulation of neurons
- 2023
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Ingår i: Biomaterials Advances. - : Elsevier BV. - 2772-9516 .- 2772-9508. ; 146
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Tidskriftsartikel (refereegranskat)abstract
- Major challenges in developing implanted neural stimulation devices are the invasiveness, complexity, and cost of the implantation procedure. Here, we report an injectable, nanofibrous 2D flexible hydrogel sheet-based neural stimulation device that can be non-invasively implanted via syringe injection for optoelectrical and biochemical dual stimulation of neuron. Specifically, methacrylated gelatin (GelMA)/alginate hydrogel nanofibers were mechanically reinforced with a poly(lactide-co-ε-caprolactone) (PLCL) core by coaxial electrospinning. The lubricant hydrogel shell enabled not only injectability, but also facile incorporation of functional nanomaterials and bioactives. The nanofibers loaded with photocatatlytic g-C3N4/GO nanoparticles were capable of stimulating neural cells via blue light, with a significant 36.3 % enhancement in neurite extension. Meanwhile, the nerve growth factor (NGF) loaded nanofibers supported a sustained release of NGF with well-maintained function to biochemically stimulate neural differentiation. We have demonstrated the capability of an injectable, hydrogel nanofibrous, neural stimulation system to support neural stimulation both optoelectrically and biochemically, which represents crucial early steps in a larger effort to create a minimally invasive system for neural stimulation.
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| 2. |
- Amagat, Jordi, et al.
(författare)
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Self-snapping hydrogel-based electroactive microchannels as nerve guidance conduits
- 2022
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Ingår i: MATERIALS TODAY BIO. - : Elsevier BV. - 2590-0064. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral nerve regeneration with large defects needs innovative design of nerve guidance conduits (NGCs) which possess anisotropic guidance, electrical induction and right mechanical properties in one. Herein, we present, for the first time, facile fabrication and efficient neural differentiation guidance of anisotropic, conductive, self-snapping, hydrogel-based NGCs. The hydrogels were fabricated via crosslinking of graphitic carbon nitride (g-C3N4) upon exposure with blue light, incorporated with graphene oxide (GO). Incorporation of GO and in situ reduction greatly enhanced surface charges, while decayed light penetration endowed the hydrogel with an intriguing self-snapping feature by the virtue of a crosslinking gradient. The hydrogels were in the optimal mechanical stiffness range for peripheral nerve regeneration and supported normal viability and proliferation of neural cells. The PC12 cells differentiated on the electroactive g-C3N4 H/rGO3 (3 mg/mL GO loading) hydrogel presented 47% longer neurite length than that of the pristine g-C3N4 H hydrogel. Furthermore, the NGC with aligned microchannels was successfully fabricated using sacrificial melt electrowriting (MEW) moulding, the anisotropic microchannels of the 10 mu m width showed optimal neurite guidance. Such anisotropic, electroactive, self-snapping NGCs may possess great potential for repairing peripheral nerve injuries.
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| 3. |
- Bortolini, C., et al.
(författare)
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Atomic Structure of Amyloid Crystals
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A deep understanding of the self-assembly and crystallization of biomolecules as highly ordered biomaterials is crucial to enable the design and the generation of complex functional systems for cutting-edge applications in nanotechnology and biomedicine. In this work, we determined the atomic structure of Aβ16-20 crystals, a fragment of amyloid-β which aberrant folding is linked to the etiology of Alzheimer’s disease, the most common cause of dementia. We detailed the hierarchical aggregation mechanism of Aβ16-20 into highly ordered crystals and revealed that the self-assembly is reversible, leading to the formation of oligomers as an intermediate. Our structural investigation combined with molecular dynamics simulations highlights how a combination of favorable non-covalent interactions drives the efficient fast self-assembly and enhanced stability. We studied the chemical and surface properties of amyloid crystals, including their mechanical properties and their capability to transmit light; the long-rang order of Aβ16-20 crystals enables them to be used as optical waveguide materials for biologically based modulation and sensing. Our results shed new light on pathogenic amyloid assembly at the atomic level and reveal the potential of amyloid crystals for applications in nanotechnology.
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| 4. |
- Song, Yongxiu, et al.
(författare)
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Identifying Heterozipper β-Sheet in Twisted Amyloid Aggregation
- 2022
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 22:9, s. 3707-3712
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid peptide (AP) self-assembly is a hierarchical process. However, the mechanistic rule of guiding peptides to organize well-ordered nanostructure in a clear and precise manner remains poorly understood. Herein we explored the molecular insight of AP motif aggregates underlying hierarchical process with helical fibrillar structure by atomic force microscope, cryo-electron microscopy (cryo-EM), and molecular dynamics simulation. AP assembly encompasses well-ordered twisted fibrils with uniform morphology, size, and periodicity. More importantly, a heterozipper β-sheet was identified in a protofilament of AP assembly determined by cryo-EM with a high resolution of 3.5 Å. Each peptide heterozipper was further composed of two antiparallel β strands and arranged by an alternative manner in a protofilament. The hydrophobic core and hydrophilic area in each zipper played the significant role for peptide assembling. This work proposed and verified the rule facilitating the basic building unit to form twisted fibrils and gave the explanation of peptide hierarchical assembling.
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| 5. |
- Su, Yingchun, et al.
(författare)
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Reshapable Osteogenic Biomaterials Combining Flexible Melt Electrowritten Organic Fibers with Inorganic Bioceramics br
- 2022
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 22:9, s. 3583-3590
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Tidskriftsartikel (refereegranskat)abstract
- Ever-growing various applications, especially for tissue regeneration, cause a pressing need for novel methods to functionalize melt electrowritten (MEW) microfibrous scaffolds with unique nanomaterials. Here, two novel strategies are proposed to modify MEW polycaprolactone (PCL) grids with ZnO nanoparticles (ZP) or ZnO nanoflakes (ZF) to enhance osteogenic differentiation. The calcium mineralization levels of MC3T3 osteoblasts cultured on PCL/ZP 0.1 scaffolds are ∼3.91-fold higher than those cultured on nonmodified PCL scaffolds, respectively. Due to the nanotopography mimicking bone anatomy, the PCL/ZF scaffolds (∼2.60 times higher in ALP activity compared to PCL/ZP 1 and ∼2.17 times higher in mineralization compared to PCL/ZP 0.1) achieved superior results. Moreover, the flexible feature inherited from PCL grids makes it possible for them to act as a reshapable osteogenic bioscaffold. This study provides new strategies for synthesizing nanomaterials on microscale surfaces, opening up a new route for functionalizing MEW scaffolds to fulfill the growing demand of tissue engineering.
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| 6. |
- Su, Yingchun, et al.
(författare)
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Surface recrystallization on melt electrowritten scaffolds for acceleration of osteogenic differentiation
- 2024
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Ingår i: Materials Today Physics. - : Elsevier BV. - 2542-5293. ; 41
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Tidskriftsartikel (refereegranskat)abstract
- As physical topographical features suggest important effects in bone tissue engineering, an increasing amount of research on surface topographies has been carried out. In this work, melt electrowritten PCL scaffolds (mPCL) with recrystallized surfaces for osteogenic differentiation were constructed. The recrystallized grid PCL scaffolds (rPCL) show strengthened mechanical properties, retained biocompatibility, enhanced expression of alkaline phosphatase, and improved calcium mineralization compared to uncrystallized mPCL scaffolds, thereby confirming the promotion of osteogenic differentiation. In addition, lumbar vertebra-like rPCL scaffolds were successfully printed for precursor osteoblast-like cells to cellularize in the desired pattern. Importantly, the combination of recrystallization method and MEW technology introduced new function into the MEW based tissue engineering scaffolds, presenting the nano/microstructure of PCL on macroscale PCL scaffolds with enhanced osteogenic activities, which especially opens a new facile route for MEW scaffolds to broaden their applications in bone tissue engineering.
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