4 research outputs found
Water Activated Graphene Oxide Transfer Using Wax Printed Membranes for Fast Patterning of a Touch Sensitive Device
We demonstrate a graphene oxide printing
technology using wax printed
membranes for the fast patterning and water activation transfer using
pressure based mechanisms. The wax printed membranes have 50 μm
resolution, longtime stability and infinite shaping capability. The
use of these membranes complemented with the vacuum filtration of
graphene oxide provides the control over the thickness. Our demonstration
provides a solvent free methodology for printing graphene oxide devices
in all shapes and all substrates using the roll-to-roll automatized
mechanism present in the wax printing machine. Graphene oxide was
transferred over a wide variety of substrates as textile or PET in
between others. Finally, we developed a touch switch sensing device
integrated in a LED electronic circuit
Cellular Cargo Delivery: Toward Assisted Fertilization by Sperm-Carrying Micromotors
We present artificially motorized
sperm cellsa novel type of hybrid micromotor, where customized
microhelices serve as motors for transporting sperm cells with motion
deficiencies to help them carry out their natural function. Our results
indicate that metal-coated polymer microhelices are suitable for this
task due to potent, controllable, and nonharmful 3D motion behavior.
We manage to capture, transport, and release single immotile live
sperm cells in fluidic channels that allow mimicking physiological
conditions. Important steps toward fertilization are addressed by
employing proper means of sperm selection and oocyte culturing. Despite
the fact that there still remain some challenges on the way to achieve
successful fertilization with artificially motorized sperms, we believe
that the potential of this novel approach toward assisted reproduction
can be already put into perspective with the present work
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Sperm-Hybrid Micromotor for Targeted Drug Delivery
A sperm-driven
micromotor is presented as a targeted drug delivery
system, which is appealing to potentially treat diseases in the female
reproductive tract. This system is demonstrated to be an efficient
drug delivery vehicle by first loading a motile sperm cell with an
anticancer drug (doxorubicin hydrochloride), guiding it magnetically,
to an <i>in vitro</i> cultured tumor spheroid, and finally
freeing the sperm cell to deliver the drug locally. The sperm release
mechanism is designed to liberate the sperm when the biohybrid micromotor
hits the tumor walls, allowing it to swim into the tumor and
deliver the drug through the sperm–cancer cell membrane
fusion. In our experiments, the sperm cells exhibited a high drug
encapsulation capability and drug carrying stability, conveniently
minimizing toxic side effects and unwanted drug accumulation
in healthy tissues. Overall, sperm cells are excellent candidates
to operate in physiological environments, as they neither express
pathogenic proteins nor proliferate to form undesirable colonies,
unlike other cells or microorganisms. This sperm-hybrid micromotor
is a biocompatible platform with potential application in gynecological
healthcare, treating or detecting cancer or other diseases in the
female reproductive system
High-Performance Three-Dimensional Tubular Nanomembrane Sensor for DNA Detection
We
report an ultrasensitive label-free DNA biosensor with fully on-chip
integrated rolled-up nanomembrane electrodes. The hybridization of
complementary DNA strands (avian influenza virus subtype H1N1) is
selectively detected down to attomolar concentrations, an unprecedented
level for miniaturized sensors without amplification. Impedimetric
DNA detection with such a rolled-up biosensor shows 4 orders of magnitude
sensitivity improvement over its planar counterpart. Furthermore,
it is observed that the impedance response of the proposed device
is contrary to the expected behavior due to its particular geometry.
To further investigate this difference, a thorough model analysis
of the measured signal and the electric field calculation is performed,
revealing enhanced electron hopping/tunneling along the DNA chains
due to an enriched electric field inside the tube. Likewise, conformational
changes of DNA might also contribute to this effect. Accordingly,
these highly integrated three-dimensional sensors provide a tool to
study electrical properties of DNA under versatile experimental conditions
and open a new avenue for novel biosensing applications (i.e., for
protein, enzyme detection, or monitoring of cell behavior under in
vivo like conditions)