8 research outputs found
Flexible Piezoelectric PMNāPT Nanowire-Based Nanocomposite and Device
Piezoelectric
nanocomposites represent a unique class of materials
that synergize the advantageous features of polymers and piezoelectric
nanostructures and have attracted extensive attention for the applications
of energy harvesting and self-powered sensing recently. Currently,
most of the piezoelectric nanocomposites were synthesized using piezoelectric
nanostructures with relatively low piezoelectric constants, resulting
in lower output currents and lower output voltages. Here, we report
a synthesis of piezoelectric (1 ā <i>x</i>)ĀPbĀ(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)ĀO<sub>3</sub>ā<i>x</i>PbTiO<sub>3</sub> (PMNāPT) nanowire-based nanocomposite with
significantly improved performances for energy harvesting and self-powered
sensing. With the high piezoelectric constant (d<sub>33</sub>) and
the unique hierarchical structure of the PMNāPT nanowires,
the PMNāPT nanowire-based nanocomposite demonstrated an output
voltage up to 7.8 V and an output current up to 2.29 Ī¼A (current
density of 4.58 Ī¼A/cm<sup>2</sup>); this output voltage is more
than double that of other reported piezoelectric nanocomposites, and
the output current is at least 6 times greater. The PMNāPT
nanowire-based nanocomposite also showed a linear relationship of
output voltage versus strain with a high sensitivity. The enhanced
performance and the flexibility of the PMNāPT nanowire-based
nanocomposite make it a promising building block for energy harvesting
and self-powered sensing applications
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The Role of Nanoparticle Design in Determining Analytical Performance of Lateral Flow Immunoassays
Rapid, simple, and
cost-effective diagnostics are needed to improve
healthcare at the point of care (POC). However, the most widely used
POC diagnostic, the lateral flow immunoassay (LFA), is ā¼1000-times
less sensitive and has a smaller analytical range than laboratory
tests, requiring a confirmatory test to establish truly negative results.
Here, a rational and systematic strategy is used to design the LFA
contrast label (i.e., gold nanoparticles) to improve the analytical
sensitivity, analytical detection range, and antigen quantification
of LFAs. Specifically, we discovered that the size (30, 60, or 100
nm) of the gold nanoparticles is a main contributor to the LFA analytical
performance through both the degree of receptor interaction and the
ultimate visual or thermal contrast signals. Using the optimal LFA
design, we demonstrated the ability to improve the analytical sensitivity
by 256-fold and expand the analytical detection range from 3 log<sub>10</sub> to 6 log<sub>10</sub> for diagnosing patients with inflammatory
conditions by measuring C-reactive protein. This work demonstrates
that, with appropriate design of the contrast label, a simple and
commonly used diagnostic technology can compete with more expensive
state-of-the-art laboratory tests
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3D Printed Programmable Release Capsules
The
development of methods for achieving precise spatiotemporal control
over chemical and biomolecular gradients could enable significant
advances in areas such as synthetic tissue engineering, bioticāabiotic
interfaces, and bionanotechnology. Living organisms guide tissue development
through highly orchestrated gradients of biomolecules that direct
cell growth, migration, and differentiation. While numerous methods
have been developed to manipulate and implement biomolecular gradients,
integrating gradients into multiplexed, three-dimensional (3D) matrices
remains a critical challenge. Here we present a method to 3D print
stimuli-responsive core/shell capsules for programmable release of
multiplexed gradients within hydrogel matrices. These capsules are
composed of an aqueous core, which can be formulated to maintain the
activity of payload biomolecules, and a polyĀ(lactic-<i>co</i>-glycolic) acid (PLGA, an FDA approved polymer) shell. Importantly,
the shell can be loaded with plasmonic gold nanorods (AuNRs), which
permits selective rupturing of the capsule when irradiated with a
laser wavelength specifically determined by the lengths of the nanorods.
This precise control over space, time, and selectivity allows for
the ability to pattern 2D and 3D multiplexed arrays of enzyme-loaded
capsules along with tunable laser-triggered rupture and release of
active enzymes into a hydrogel ambient. The advantages of this 3D
printing-based method include (1) highly monodisperse capsules, (2)
efficient encapsulation of biomolecular payloads, (3) precise spatial
patterning of capsule arrays, (4) āon the flyā programmable
reconfiguration of gradients, and (5) versatility for incorporation
in hierarchical architectures. Indeed, 3D printing of programmable
release capsules may represent a powerful new tool to enable spatiotemporal
control over biomolecular gradients
3D Printed Bionic Ears
The
ability to three-dimensionally interweave biological tissue with functional
electronics could enable the creation of bionic organs possessing
enhanced functionalities over their human counterparts. Conventional
electronic devices are inherently two-dimensional, preventing seamless
multidimensional integration with synthetic biology, as the processes
and materials are very different. Here, we present a novel strategy
for overcoming these difficulties via additive manufacturing of biological
cells with structural and nanoparticle derived electronic elements.
As a proof of concept, we generated a bionic ear via 3D printing of
a cell-seeded hydrogel matrix in the anatomic geometry of a human
ear, along with an intertwined conducting polymer consisting of infused
silver nanoparticles. This allowed for in vitro culturing of cartilage
tissue around an inductive coil antenna in the ear, which subsequently
enables readout of inductively-coupled signals from cochlea-shaped
electrodes. The printed ear exhibits enhanced auditory sensing for
radio frequency reception, and complementary left and right ears can
listen to stereo audio music. Overall, our approach suggests a means
to intricately merge biologic and nanoelectronic functionalities via
3D printing
3D Printed Bionic Ears
The
ability to three-dimensionally interweave biological tissue with functional
electronics could enable the creation of bionic organs possessing
enhanced functionalities over their human counterparts. Conventional
electronic devices are inherently two-dimensional, preventing seamless
multidimensional integration with synthetic biology, as the processes
and materials are very different. Here, we present a novel strategy
for overcoming these difficulties via additive manufacturing of biological
cells with structural and nanoparticle derived electronic elements.
As a proof of concept, we generated a bionic ear via 3D printing of
a cell-seeded hydrogel matrix in the anatomic geometry of a human
ear, along with an intertwined conducting polymer consisting of infused
silver nanoparticles. This allowed for in vitro culturing of cartilage
tissue around an inductive coil antenna in the ear, which subsequently
enables readout of inductively-coupled signals from cochlea-shaped
electrodes. The printed ear exhibits enhanced auditory sensing for
radio frequency reception, and complementary left and right ears can
listen to stereo audio music. Overall, our approach suggests a means
to intricately merge biologic and nanoelectronic functionalities via
3D printing
3D Printed Bionic Ears
The
ability to three-dimensionally interweave biological tissue with functional
electronics could enable the creation of bionic organs possessing
enhanced functionalities over their human counterparts. Conventional
electronic devices are inherently two-dimensional, preventing seamless
multidimensional integration with synthetic biology, as the processes
and materials are very different. Here, we present a novel strategy
for overcoming these difficulties via additive manufacturing of biological
cells with structural and nanoparticle derived electronic elements.
As a proof of concept, we generated a bionic ear via 3D printing of
a cell-seeded hydrogel matrix in the anatomic geometry of a human
ear, along with an intertwined conducting polymer consisting of infused
silver nanoparticles. This allowed for in vitro culturing of cartilage
tissue around an inductive coil antenna in the ear, which subsequently
enables readout of inductively-coupled signals from cochlea-shaped
electrodes. The printed ear exhibits enhanced auditory sensing for
radio frequency reception, and complementary left and right ears can
listen to stereo audio music. Overall, our approach suggests a means
to intricately merge biologic and nanoelectronic functionalities via
3D printing
3D Printed Quantum Dot Light-Emitting Diodes
Developing the ability to 3D print
various classes of materials possessing distinct properties could
enable the freeform generation of active electronics in unique functional,
interwoven architectures. Achieving seamless integration of diverse
materials with 3D printing is a significant challenge that requires
overcoming discrepancies in material properties in addition to ensuring
that all the materials are compatible with the 3D printing process.
To date, 3D printing has been limited to specific plastics, passive
conductors, and a few biological materials. Here, we show that diverse
classes of materials can be 3D printed and fully integrated into device
components with active properties. Specifically, we demonstrate the
seamless interweaving of five different materials, including (1) emissive
semiconducting inorganic nanoparticles, (2) an elastomeric matrix,
(3) organic polymers as charge transport layers, (4) solid and liquid
metal leads, and (5) a UV-adhesive transparent substrate layer. As
a proof of concept for demonstrating the integrated functionality
of these materials, we 3D printed quantum dot-based light-emitting
diodes (QD-LEDs) that exhibit pure and tunable color emission properties.
By further incorporating the 3D scanning of surface topologies, we
demonstrate the ability to conformally print devices onto curvilinear
surfaces, such as contact lenses. Finally, we show that novel architectures
that are not easily accessed using standard microfabrication techniques
can be constructed, by 3D printing a 2 Ć 2 Ć 2 cube of encapsulated
LEDs, in which every component of the cube and electronics are 3D
printed. Overall, these results suggest that 3D printing is more versatile
than has been demonstrated to date and is capable of integrating many
distinct classes of materials
Biotemplated Synthesis of PZT Nanowires
Piezoelectric
nanowires are an important class of smart materials
for next-generation applications including energy harvesting, robotic
actuation, and bioMEMS. Lead zirconate titanate (PZT), in particular,
has attracted significant attention, owing to its superior electromechanical
conversion performance. Yet, the ability to synthesize crystalline
PZT nanowires with well-controlled properties remains a challenge.
Applications of common nanosynthesis methods to PZT are hampered by
issues such as slow kinetics, lack of suitable catalysts, and harsh
reaction conditions. Here we report a versatile biomimetic method,
in which biotemplates are used to define PZT nanostructures, allowing
for rational control over composition and crystallinity. Specifically,
stoichiometric PZT nanowires were synthesized using both polysaccharide
(alginate) and bacteriophage templates. The wires possessed measured
piezoelectric constants of up to 132 pm/V after poling, among the
highest reported for PZT nanomaterials. Further, integrated devices
can generate up to 0.820 Ī¼W/cm<sup>2</sup> of power. These results
suggest that biotemplated piezoelectric nanowires are attractive candidates
for stimuli-responsive nanosensors, adaptive nanoactuators, and nanoscale
energy harvesters