Nanofibrous
aerogels have been extensively developed as multifunctional
substrates in a wide range of fields. Natural silk nanofibrils (SNFs)
are an appealing biopolymer due to their natural abundance, mechanical
toughness, biodegradability, and excellent biocompatibility. However,
fabricating 3D SNF materials with mechanical flexibility remains a
challenge. Herein, SNF-based aerogels with controlled structures and
well mechanical resilience were prepared. SNFs were extracted from
silkworm silks by mechanical disintegration based on an all-aqueous
system. The nanofibrils network and hierarchical cellular structure
of the aerogels were tuned by the assembly of SNFs and foreign poly(vinyl
alcohol) (PVA). The SNF aerogels exhibited an ultralow density (as
low as 2.0 mg·cm–3) and well mechanical properties
with a structure allowing for large deformations. These SNF aerogels
demonstrated a reversible compression and stress retention after 100
cycles of compression. Furthermore, the resulting aerogels were used
for air filtration and showed efficient filtration performance with
a high dust-holding capacity and low resistance. Moreover, an extremely
low thermal conductivity of 0.028 W·(m·K)−1 was achieved by the aerogel, showing its potential for use in heat-retention
applications. This study provides a useful strategy for exploring
the use of natural silks in 3D aerogels and offers options for developing
filtration materials and ultralight heat-retention materials.
Neural interface is a powerful tool to control the varying neuron activities in brain, where the performance can directly affect the quality of recording neural signals and the reliability of...
As a natural high-performance material with a unique hierarchical structure, silk is endowed with superior mechanical properties. However, the current approaches towards producing regenerated silk fibroin (SF) for the preparation of biomedical devices fail to fully exploit the mechanical potential of native silk materials. In this study, using a top-down approach, we exfoliated natural silk fibers into silk nanofibrils (SNFs), through the disintegration of interfibrillar binding forces. The as-prepared SNFs were employed to reinforce the regenerated SF solution to fabricate orthopedic screws with outstanding mechanical properties (compression modulus > 1.1 GPa in a hydrated state). Remarkably, these screws exhibited tunable biodegradation and high cytocompatibility. After 28 days of degradation in protease XIV solution, the weight loss of the screw was ~20% of the original weight. The screws offered a favorable microenvironment to human bone marrow mesenchymal stem cell growth and spread as determined by live/dead staining, F-action staining, and Alamar blue staining. The synergy between native structural components (SNFs) and regenerated SF solutions to form bionanocomposites provides a promising design strategy for the fabrication of biomedical devices with improved performance.
Protein hydrogels is an important biomaterial for soft tissue repair in biomedical applications. However, the most extracellular matrixes are structured and ordered, the morphology of common hydrogels are of random network structures that impeded their applications in tissue engineering. In this study, silk fibroin hydrogels with different morphologies (i.e., microspheres, regularized beads, nano/micro fibers, intertwined networks, and multi-walls) were prepared under low voltage electrostatic fields by regulating the concentration of silk fibroin solution. Additionally, their stability can be regulated with further processing routes to satisfy the tailored requirements for different applications. Fourier transform infrared spectrometer (FTIR) and X-ray diffraction (XRD) provided evidence of the stability of silk fibroin electro materials was tuned by this method effectively. Therefore, these silk fibroin electro hydrogels with various morphologies, high orientation, and stability-regulatable properties provided a promising candidate for tissue engineering.
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