18 research outputs found
Rapid Electromechanical Transduction on a Single-Walled Carbon Nanotube Film: Sensing Fast Mechanical Loading via Detection of Electrical Signal Change
Carbon nanotubes (CNTs) have been widely explored as
next generation
embedded-strain-pressure sensors. However, most investigations of
CNT sensors did not consider the response time as a critical factor,
although the ultrafast sensing of mechanical deformation is very important
for the detection of dynamic loading or impact, such as in reactive
armor systems. Owing to the low capacitance that shortens the response
time of the electrical resistance changes induced by mechanical deformation,
CNTs are expected to detect rapid electromechanical transduction without
delay. Herein, we fabricate single-walled carbon nanotube (SWNT) films
on diverse substrates, and evaluate their applications as sensors
to detect rapid electromechanical transduction on a macroscopic scale.
Under repetitive, high-speed mechanical loading, the SWNT films generate
consistent electrical signal changes, which are accurately synchronized
with their strain and the beginning of the deformation
Multilayered Controlled Drug Release Silk Fibroin Nanofilm by Manipulating Secondary Structure
Many
studies of drug delivery nanoplatforms have explored drug
loading affinity and controlled release. The nanoplatforms can be
influenced by their inherent building blocks. Natural polypeptide
silk fibroin (SF) is an excellent nanoplatform material because of
its high biocompatibility and unique structural properties. SF secondary
structures have different properties that can be changed by external
stimuli. Thus, the characterization of SF-containing platforms is
strongly affected by secondary structure transformations. Structural
changes can occur spontaneously, which hinders the control of structural
variation in aqueous conditions. Herein, we successfully prepared
a controllable secondary structure composed of SF/heparin (HEP) layer-by-layer
assembled nanofilms using simple solvents (glycerol and methanol).
SF in the SF/HEP nanofilms takes up than 90%, which means configurations
of SF have a strong effect on the character of the nanofilms. We investigated
the degradation profiles of SF/HEP nanofilms depending on their β-sheet
contents and demonstrated an immediate correlation between the transformation
of secondary structures inside the nanofilms and the degree of degradation
of nanofilms. Finally, SF/HEP nanofilms were used as a delivery platform
for incorporating the anticancer drug epirubicin (EPI). We could control
the loading efficiency and release profile of EPI with various β-sheet
contents of the nanofilms
Spontaneous Biomacromolecule Absorption and Long-Term Release by Graphene Oxide
Biomacromolecule
loading is the popular research in the biomedical
field. To control the loading amount and releasing profile, various
materials and fabrication techniques were developed. In this study,
layer-by-layer assembly of multilayer films between collagen (Col)
and graphene oxide (GO) was used to control the release of the loading
molecule. By mixing GO into the system, ovalbumin (OVA) can be spontaneously
adsorbed onto the GO sheet (denoted as GO/OVA) via the hydrophobic
interaction. Two kinds of multilayer films (Col/GO/OVA and Col/GO/OVA)
were fabricated. The thickness growth curve, quantitative of each
layer adsorption, film morphology, stability, cell viability, and
OVA release from multilayer films were investigated. The result has
shown excellent film stability, macromolecule loading, and sustained
release because of GO ability
Inkjet Printing-Based Patchable Multilayered Biomolecule-Containing Nanofilms for Biomedical Applications
Thin
films including biocompatible polymers and biological materials
as building blocks can be produced with a variety of critical film
characteristics, including various materials, thicknesses, roughnesses,
amounts of compound released, and release rates for biomedical purposes.
We developed a multilayer fabrication system via high-throughput layer-by-layer
(LbL) assembly of a nanofilm with inkjet printing to facilitate practical
biomedical applications. Our system was used to generate biomolecule
(ovalbumin and basic fibroblast growth factor)-containing printed
LbL films. This is the first demonstration of the clinical benefits
of nanofilm-type nanobiomaterials based on molecular organization,
suggesting that novel therapeutic human skin patches could be realized
without the need for conventional surgical practices
Drug Loading and Release Behavior Depending on the Induced Porosity of Chitosan/Cellulose Multilayer Nanofilms
The
ability to control drug loading and release is the most important
feature in the development of medical devices. In this research, we
prepared a functional nanocoating technology to incorporate a drug-release
layer onto a desired substrate. The multilayer films were prepared
using chitosan (CHI) and carboxymethyl cellulose (CMC) polysaccharides
by the layer-by-layer (LbL) method. By using chemical cross-linking
to change the inner structure of the assembled multilayer, we could
control the extent of drug loading and release. The cross-linked multilayer
film had a porous structure and enhanced water wettability. Interestingly,
more of the small-molecule drug was loaded into and released from
the non-cross-linked multilayer film, whereas more of the macromolecular
drug was loaded into and released from the cross-linked multilayer
film. These results indicate that drug loading and release can be
easily controlled according to the molecular weight of the desired
drug by changing the structure of the film
Multifunctional Collagen and Hyaluronic Acid Multilayer Films on Live Mesenchymal Stem Cells
Cell
encapsulation has been reported to convey cytoprotective effects and
to better maintain cell survival. In contrast to other studies, our
report shows that the deposition of two major biomacromolecules, collagen
type I (Col) and hyaluronic acid (HA), on mesenchymal stem cells (MSCs)
does not entirely block the cell plasma membrane surface. Instead,
a considerable amount of the surface remained uncovered or only slightly
covered, as confirmed by TEM observation and by FACS analysis based
on quantitative surface labeling. Despite this structure showing openness
and flexibility, the multilayer Col/HA films significantly increased
cell survival in the attachment-deprived culture condition. In terms
of stem cell characteristics, the MSCs still showed functional cell
activity after film deposition, as evidenced by their colony-forming
activity and in vitro osteogenic differentiation. The Col/HA multilayer
films could provide a cytoprotective effect and induce osteogenic
differentiation without deteriorating effect or inhibition of cellular
attachment, showing that this technique can be a valuable tool for
modulating stem cell activities
Efficient Encapsulation and Sustained Release of Basic Fibroblast Growth Factor in Nanofilm: Extension of the Feeding Cycle of Human Induced Pluripotent Stem Cell Culture
Basic fibroblast
growth factor (bFGF) has an established pivotal function in biomedical
engineering, especially for the human pluripotent stem cells (iPSCs).
However, the limitation of bFGF is the ease of denaturation under
normal physiological conditions, inducing loss of its activity. In
this study, we designed multi-trilayered nanofilm composed of a repeating
polycation/polyanion/bFGF structure, which has high loading efficiency
and short buildup time. We also investigated that the loading and
release of bFGF from the nanofilm with two parameters (counter-polyanion
and film architectures). Then, we prepared the optimized nanofilm
which maintains a sustained bFGF level in physiological condition
to apply the nanofilm to human iPSCs culture. The amount of bFGF release
from 12 trilayer nanofilm was 36.4 ng/cm<sup>2</sup>, and activity
of bFGF encapsulated into the nanofilm was maintained (60%) until
72 h during incubation at 37 °C. As a result, the iPSCs grown
in the presence of the nanofilm with tridaily replacement of growth
medium maintained undifferentiated morphology and expression levels
of pluripotency marker proteins
Durable Urushiol-Based Nanofilm with Water Repellency for Clear Overlay Appliances in Dentistry
With increased esthetic needs, orthodontics
is an indispensable
medical treatment in dentistry, and transparent clear overlay appliances
(COAs) are in general use to fix teeth. However, COAs are easily worn
out because of the lack of durability. Here, we applied a nanofilm
onto COAs using urushiol (U), a durable coating material from plant
via a layer-by-layer assembly technique. In particular, polymerized
urushiol (PU) provided COAs with higher mechanical strength in the
large-scale assessment, lower cytotoxicity, and intrinsic hydrophobicity
for antimicrobial use. In this report, we inceptively attempted to
functionalize COAs with nanofilm for advanced biomedical use
Synthesis and Characterization of Functional Nanofilm-Coated Live Immune Cells
Layer-by-layer
(LbL) assembly techniques have been extensively studied in cell biology
because of their simplicity of preparation and versatility. The applications
of the LbL platform technology using polysaccharides, silicon, and
graphene have been investigated. However, the applications of the
above-mentioned technology using living cells remain to be fully understood.
This study demonstrates a living cell-based LbL platform using various
types of living cells. In addition, it confirms that the surplus charge
on the outer surface of the coated cells can be used to bind the target
protein. We develop a living cell-based LbL platform technology by
stacking layers of hyaluronic acid (HA) and poly-l-lysine
(PLL). The HA/PLL stacking results in three bilayers with a thickness
of 4 ± 1 nm on the cell surface. Furthermore, the multilayer
nanofilms on the cells are completely degraded after 3 days of the
application of the LbL method. We also evaluate and visualize three
bilayers of the nanofilm on adherent (AML-12 cells)-, nonadherent
(trypsin-treated AML-12 cells)-, and circulation type [peripheral
blood mononuclear cells (PBMCs)] cells by analyzing the zeta potential,
cell viability, and imaging via scanning electron microscopy and confocal
microscopy. Finally, we study the cytotoxicity of the nanofilm and
characteristic functions of the immune cells after the nanofilm coating.
The multilayer nanofilms are not acutely cytotoxic and did not inhibit
the immune response of the PBMCs against stimulant. We conclude that
a two bilayer nanofilm would be ideal for further study in any cell
type. The living cell-based LbL platform is expected to be useful
for a variety of applications in cell biology
Intrinsic Hydrophobic Cairnlike Multilayer Films for Antibacterial Effect with Enhanced Durability
One
important aspect of nanotechnology includes thin films capable of
being applied to a wide variety of surfaces. Indispensable functions
of films include controlled surface energy, stability, and biocompatibility
in physiological systems. In this study, we explored the ancient Asian
coating material “lacquer” to enhance the physiological
and mechanical stability of nanofilms. Lacquer is extracted from the
lacquer tree and its main component called urushiol, which is a small
molecule that can produce an extremely strong coating. Taking full
advantage of layer-by-layer assembly techniques, we successfully fabricated
urushiol-based thin films composed of small molecule/polymer multilayers
by controlling their molecular interaction. Unique cairnlike nanostructures
in this film, produced by urushiol particles, have advantages of intrinsic
hydrophobicity and durability against mechanical stimuli at physiological
environment. We demonstrated the stability tests as well as the antimicrobial
effects of this film