4 research outputs found
Improved Mechanical Properties and Sustained Release Behavior of Cationic Cellulose Nanocrystals Reinforeced Cationic Cellulose Injectable Hydrogels
Polysaccharide-based
injectable hydrogels have several advantages
in the context of biomedical use. However, the main obstruction associated
with the utilization of these hydrogels in clinical application is
their poor mechanical properties. Herein, we describe <i>in situ</i> gelling of nanocomposite hydrogels based on quaternized cellulose
(QC) and rigid rod-like cationic cellulose nanocrystals (CCNCs), which
can overcome this challenge. In all cases, gelation immediately occurred
with an increase of temperature, and the CCNCs were evenly distributed
throughout the hydrogels. The nanocomposite hydrogels exhibited increasing
orders-of-magnitude in the mechanical strength, high extension in
degradation and the sustained release time, because of the strong
interaction between CCNCs and QC chains mediated by the cross-linking
agent (β-glycerophosphate, β-GP). The results of the <i>in vitro</i> toxicity and <i>in vivo</i> biocompatibility
tests revealed that the hydrogels did not show obvious cytotoxicity
and inflammatory reaction to cells and tissue. Moreover, DOX-encapsulated
hydrogels were injected beside the tumors of mice bearing liver cancer
xenografts to assess the potential utility as localized and sustained
drug delivery depot systems for anticancer therapy. The results suggested
that the QC/CCNC/β-GP nanocomposite hydrogels had great potential
for application in subcutaneous and sustained delivery of anticancer
drug to increase therapeutic efficacy and improve patient compliance
Fast Contact of Solid–Liquid Interface Created High Strength Multi-Layered Cellulose Hydrogels with Controllable Size
Novel onion-like and multi-layered
tubular cellulose hydrogels
were constructed, for the first time, from the cellulose solution
in a 7% NaOH/12% urea aqueous solvent by changing the shape of the
gel cores. In our findings, the contacting of the cellulose solution
with the surface of the agarose gel rod or sphere loaded with acetic
acid led to the close chain packing to form immediately a gel layer,
as a result of the destruction of the cellulose inclusion complex
by acid through inducing the cellulose self-aggregation. Subsequently,
multi-layered cellulose hydrogels were fabricated via a multi-step
interrupted gelation process. The size, layer thickness and inter-layer
space of the multi-layered hydrogels could be controlled by adjusting
the cellulose concentrations, the gel core diameter and the contacting
time of the solid–liquid interface. The multi-layered cellulose
hydrogels displayed good architectural stability and solvent resistance.
Moreover, the hydrogels exhibited high compressive strength and excellent
biocompatibility. L929 cells could adhere and proliferate on the surface
of the layers and in interior space, showing great potential as tissue
engineering scaffolds and cell culture carrier. This work opens up
a new avenue for the construction of the high strength multi-layered
cellulose hydrogels formed from inner to outside via a fast contact
of solid–liquid interface
Construction of Chitin/PVA Composite Hydrogels with Jellyfish Gel-Like Structure and Their Biocompatibility
High
strength chitin/polyÂ(vinyl alcohol) (PVA) composite hydrogels
(RCP) were constructed by adding PVA into chitin dissolved in a NaOH/urea
aqueous solution, and then by cross-linking with epichlorohydrin (ECH)
and freezing–thawing process. The RCP hydrogels were characterized
by field emission scanning electron microscopy, FTIR, differential
scanning calorimetry, solid-state <sup>13</sup>C NMR, wide-angle X-ray
diffraction, and compressive test. The results revealed that the repeated
freezing/thawing cycles induced the bicrosslinked networks consisted
of chitin and PVA crystals in the composite gels. Interestingly, a
jellyfish gel-like structure occurred in the RCP75 gel with 25 wt
% PVA content in which the amorphous and crystalline PVA were immobilized
tightly in the chitin matrix through hydrogen bonding interaction.
The freezing/thawing cycles played an important role in the formation
of the layered porous PVA networks and the tight combining of PVA
with the pore wall of chitin. The mechanical properties of RCP75 were
much higher than the other RCP gels, and the compressive strength
was 20Ă— higher than that of pure chitin gels, as a result of
broadly dispersing stress caused by the orderly multilayered networks.
Furthermore, the cell culture tests indicated that the chitin/PVA
composite hydrogels exhibited excellent biocompatibility and safety,
showing potential applications in the field of tissue engineering
Epichlorohydrin-Cross-linked Hydroxyethyl Cellulose/Soy Protein Isolate Composite Films as Biocompatible and Biodegradable Implants for Tissue Engineering
A series of epichlorohydrin-cross-linked
hydroxyethyl cellulose/soy protein isolate composite films (EHSF)
was fabricated from hydroxyethyl cellulose (HEC) and soy protein isolate
(SPI) using a process involving blending, cross-linking, solution
casting, and evaporation. The films were characterized with FTIR,
solid-state <sup>13</sup>C NMR, UV–vis spectroscopy, and mechanical
testing. The results indicated that cross-linking interactions occurred
in the inter- and intramolecules of HEC and SPI during the fabrication
process. The EHSF films exhibited homogeneous structure and relative
high light transmittance, indicating there was a certain degree of
miscibility between HEC and SPI. The EHSF films exhibited a relative
high mechanical strength in humid state and an adjustable water uptake
ratio and moisture absorption ratio. Cytocompatibility, hemocompatibility
and biodegradability were evaluated by a series of in vitro and in
vivo experiments. These results showed that the EHSF films had good
biocompatibility, hemocompatibility, and anticoagulant effect. Furthermore,
EHSF films could be degraded in vitro and in vivo, and the degradation
rate could be controlled by adjusting the SPI content. Hence, EHSF
films might have a great potential for use in the biomedical field