6 research outputs found
Self-growth of micro- and nano-structured Mg(OH)<sub>2</sub> on electrochemically anodised Mg–Li alloy surface
<div><p>Formation of Mg(OH)<sub>2</sub> nanowires and their assemblies with sphere-shaped, echinus-shaped and nest-like micro-structures on a Mg-Li alloy surface was successfully demonstrated. Mg(OH)<sub>2</sub> nanowires were formed on the alloy surface via a self-growth process, after the alloy was electrooxidised in NaCl solution and the oxidation products were removed. The nanowires were characterised by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Infrared spectroscopy. The nanowires have hexagonal rod-like or brush-like morphology and are poorly crystallised. Pre-anodisation and the presence of Li in the alloy are key factors for the nanowire growth, which likely proceeds via a dissolution–precipitation mechanism. The roles of Li can be attributed to the prohibition of the formation of passivation film on the alloy surface and the acceleration of the formation of OH<sup>−</sup> anions through hydrogen-evolution reaction.</p></div
Direct 3D Bioprinting of Tough and Antifatigue Cell-Laden Constructs Enabled by a Self-Healing Hydrogel Bioink
Three-dimensional (3D) extrusion
bioprinting has emerged as one
of the most promising biofabrication technologies for preparing biomimetic
tissue-like constructs. The successful construction of cell-laden
constructs majorly relies on the development of proper bioinks with
excellent printability and cytocompatibility. Bioinks based on gelatin
methacryloyl (GelMA) have been widely explored due to the excellent
biocompatibility and biodegradability and the presence of the arginine–glycine–aspartic
acid (RGD) sequences for cell adhesion. However, such bioinks usually
require low-temperature or ionic cross-linking systems to solidify
the extruded hydrogel structures, which results in complex processes
and limitations to certain applications. Moreover, many current hydrogel-based
bioinks, even after chemical cross-linking, hardly possess the required
strength to resist the mechanical loads during the implantation procedure.
Herein, we report a self-healing hydrogel bioink based on GelMA and
oxidized dextran (OD) for the direct printing of tough and fatigue-resistant
cell-laden constructs at room temperature without any template or
cross-linking agents. Enabled by dynamic Schiff base chemistry, the
mixed GelMA/OD solution showed the characteristics of a dynamic hydrogel
with shear-thinning and self-supporting behavior, which allows bridging
the 5 mm gap and efficient direct bioprinting of complex constructs
with high shape fidelity. After photo-cross-linking, the resulting
tissue constructs exhibited excellent low cell damage, high cell viability,
and enhanced mechanical strength. Moreover, the GelMA/OD construct
could resist up to 95% compressive deformation without any breakage
and was able to maintain 80% of the original Young’s modulus
during long-term loading (50 cycles). It is believed that our GelMA/OD
bioink would expand the potential of GelMA-based bioinks in applications
such as tissue engineering and pharmaceutical screening
Direct 3D Bioprinting of Tough and Antifatigue Cell-Laden Constructs Enabled by a Self-Healing Hydrogel Bioink
Three-dimensional (3D) extrusion
bioprinting has emerged as one
of the most promising biofabrication technologies for preparing biomimetic
tissue-like constructs. The successful construction of cell-laden
constructs majorly relies on the development of proper bioinks with
excellent printability and cytocompatibility. Bioinks based on gelatin
methacryloyl (GelMA) have been widely explored due to the excellent
biocompatibility and biodegradability and the presence of the arginine–glycine–aspartic
acid (RGD) sequences for cell adhesion. However, such bioinks usually
require low-temperature or ionic cross-linking systems to solidify
the extruded hydrogel structures, which results in complex processes
and limitations to certain applications. Moreover, many current hydrogel-based
bioinks, even after chemical cross-linking, hardly possess the required
strength to resist the mechanical loads during the implantation procedure.
Herein, we report a self-healing hydrogel bioink based on GelMA and
oxidized dextran (OD) for the direct printing of tough and fatigue-resistant
cell-laden constructs at room temperature without any template or
cross-linking agents. Enabled by dynamic Schiff base chemistry, the
mixed GelMA/OD solution showed the characteristics of a dynamic hydrogel
with shear-thinning and self-supporting behavior, which allows bridging
the 5 mm gap and efficient direct bioprinting of complex constructs
with high shape fidelity. After photo-cross-linking, the resulting
tissue constructs exhibited excellent low cell damage, high cell viability,
and enhanced mechanical strength. Moreover, the GelMA/OD construct
could resist up to 95% compressive deformation without any breakage
and was able to maintain 80% of the original Young’s modulus
during long-term loading (50 cycles). It is believed that our GelMA/OD
bioink would expand the potential of GelMA-based bioinks in applications
such as tissue engineering and pharmaceutical screening
Direct 3D Bioprinting of Tough and Antifatigue Cell-Laden Constructs Enabled by a Self-Healing Hydrogel Bioink
Three-dimensional (3D) extrusion
bioprinting has emerged as one
of the most promising biofabrication technologies for preparing biomimetic
tissue-like constructs. The successful construction of cell-laden
constructs majorly relies on the development of proper bioinks with
excellent printability and cytocompatibility. Bioinks based on gelatin
methacryloyl (GelMA) have been widely explored due to the excellent
biocompatibility and biodegradability and the presence of the arginine–glycine–aspartic
acid (RGD) sequences for cell adhesion. However, such bioinks usually
require low-temperature or ionic cross-linking systems to solidify
the extruded hydrogel structures, which results in complex processes
and limitations to certain applications. Moreover, many current hydrogel-based
bioinks, even after chemical cross-linking, hardly possess the required
strength to resist the mechanical loads during the implantation procedure.
Herein, we report a self-healing hydrogel bioink based on GelMA and
oxidized dextran (OD) for the direct printing of tough and fatigue-resistant
cell-laden constructs at room temperature without any template or
cross-linking agents. Enabled by dynamic Schiff base chemistry, the
mixed GelMA/OD solution showed the characteristics of a dynamic hydrogel
with shear-thinning and self-supporting behavior, which allows bridging
the 5 mm gap and efficient direct bioprinting of complex constructs
with high shape fidelity. After photo-cross-linking, the resulting
tissue constructs exhibited excellent low cell damage, high cell viability,
and enhanced mechanical strength. Moreover, the GelMA/OD construct
could resist up to 95% compressive deformation without any breakage
and was able to maintain 80% of the original Young’s modulus
during long-term loading (50 cycles). It is believed that our GelMA/OD
bioink would expand the potential of GelMA-based bioinks in applications
such as tissue engineering and pharmaceutical screening
Direct 3D Bioprinting of Tough and Antifatigue Cell-Laden Constructs Enabled by a Self-Healing Hydrogel Bioink
Three-dimensional (3D) extrusion
bioprinting has emerged as one
of the most promising biofabrication technologies for preparing biomimetic
tissue-like constructs. The successful construction of cell-laden
constructs majorly relies on the development of proper bioinks with
excellent printability and cytocompatibility. Bioinks based on gelatin
methacryloyl (GelMA) have been widely explored due to the excellent
biocompatibility and biodegradability and the presence of the arginine–glycine–aspartic
acid (RGD) sequences for cell adhesion. However, such bioinks usually
require low-temperature or ionic cross-linking systems to solidify
the extruded hydrogel structures, which results in complex processes
and limitations to certain applications. Moreover, many current hydrogel-based
bioinks, even after chemical cross-linking, hardly possess the required
strength to resist the mechanical loads during the implantation procedure.
Herein, we report a self-healing hydrogel bioink based on GelMA and
oxidized dextran (OD) for the direct printing of tough and fatigue-resistant
cell-laden constructs at room temperature without any template or
cross-linking agents. Enabled by dynamic Schiff base chemistry, the
mixed GelMA/OD solution showed the characteristics of a dynamic hydrogel
with shear-thinning and self-supporting behavior, which allows bridging
the 5 mm gap and efficient direct bioprinting of complex constructs
with high shape fidelity. After photo-cross-linking, the resulting
tissue constructs exhibited excellent low cell damage, high cell viability,
and enhanced mechanical strength. Moreover, the GelMA/OD construct
could resist up to 95% compressive deformation without any breakage
and was able to maintain 80% of the original Young’s modulus
during long-term loading (50 cycles). It is believed that our GelMA/OD
bioink would expand the potential of GelMA-based bioinks in applications
such as tissue engineering and pharmaceutical screening
Nano Endoscopy with Plasmon-Enhanced Fluorescence for Sensitive Sensing Inside Ultrasmall Volume Samples
Plasmon-enhanced
fluorescence (PEF) generally requires the samples
settled on a metal substrate and the effective enhancement distance
is less than 100 nm, which limit its application in intracellular
sensing. Herein, we report a nano endoscopy with PEF effect for sensing
analytes inside the extremely small volume samples. The nano endoscopy
was fabricated by assembling single nanoporous gold nanowire (PGNW)
on the tip of a tungsten needle. It was accurately manipulated to
insert into a micro droplet, and an effective sensing was realized
at micrometre scale with submicrometer resolution. By taking lysozyme
as a model sensing target, a 23-fold improvement of sensitivity was
obtained, comparing with that of smooth gold nanowire (SGNW). These
results indicated that the nano endoscopy can realize a high spatial
resolution sensing, showing its potential application in intracellular
sensing