Category Archives: Medical electronics

Electrophoretic drug delivery for seizure control

Journal: Science Advances

Authors: C. M. Proctor and G. G. Malliaras et al.

Affiliation: The University of Cambridge (UK)

Publication date: 2018.08.29

Summarized by Inyeol Yun

 

– Topics
v. Neural probes incorporation an ion pump for on-demand drug delivery and   electrodes for recording local neural activity. (Fig. 1)
v. Seizure-like events (SLE) were induced by local injection of 4-aminopryridine (4AP)
v. γ-aminobutryic acid (GABA) inhibit neural activity.

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<Fig. 1>

–Fabrication
v. Gold electrode: ion pump source electrode, PEDOT:PSS electrode : recording   electrophysiological activity (Fig. 2)

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<Fig. 2>

– Results
v. Ion transfer efficiency: ~10-3 nmol of GABA transported in few seconds (Fig. 3)

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<Fig. 3>

  v. Seizure control (Fig. 4)

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<Fig. 4>

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Flexible wireless powered drug delivery system for targeted administration on cerebral cortex

Journal: Nano Energy

Authors: S. Sung and K. Lee et al.

Affiliation: KAIST (Republic of Korea)

Publication date: 2018.06.07

Summarized by Inyeol Yun

 

– Flexible wireless powered drug delivery system (Fig. 1)

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<Fig. 1>

– Device fabrication
v. Structure (Fig. 2)

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<Fig. 2>

 v. Steps (Fig. 3)

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<Fig. 3>

– Technical points
v. Heat transfer simulation (LLO damage x) (Fig.4)

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<Fig. 4>

 v. Gold membrane dissolution process (Fig. 5)

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5

<Fig. 5>

  v. Wireless power efficiency (Fig. 6)

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<Fig. 6>

Biodegradable Piezoelectric Force Sensor

Journal: Proceedings of the National Academy of Sciences

Author: Eli J. Curry and Thanh D. Nguyen et al.

Affiliation: University of Connecticut

Publication date: 2018.01.16

Summarized by Inyeol Yun

 

– Structure
v. PLA Encapsulator – Molybdenum – Piezo. PLLA – Molybdenum – PLA Encapsulator (Fig. 1)

fig1.png

Fig. 1

 

– Fabrication
v. Cut the Molybdenum and PLLA film.
v. The PLLA film was sandwiched between two Mo electrodes.
v. Encapsulator was sealed using a combination of the biodegradable PLLA glue and a thermal bag sealer for 4 seconds. (Fig. 2)

fig2.png

Fig. 2

 

– Principle
v. Piezoelectricity (Fig. 3)
v. PLLA : new piezoelectric material (normally not piezoelectric material) (Fig. 4)
v. PLLA -> shear stress -> nucleation -> piezoelectricity (Fig. 5)

fig3.png

Fig. 3

fig4.png

Fig. 4

fig5

Fig. 5

 

– Result
v. Vibration test: Drain ratio (DR) 2.5 output is largest but it is not conclusive optimal DR (Fig. 6)
v. Pressure – Voltage with charge amplifier circuit
v. Biocompatible, Biodegradable test (Fig. 7)
v. In-vivo test: inside the abdominal cavity of a mouse to monitor the pressure of diaphragmatic contraction (Fig. 8)

fig6.png

Fig. 6

fig7.png

Fig. 7

fig8.png

Fig. 8

Accelerated Wound Healing on Skin by Electrical Stimulation with a Bioelectric Plaster

Journal: Advanced Healthcare Materials

Author: Hiroyuki Kai and Matsuhiko Nishizawa et al.

Affiliation: Tohoku University, Japan

Publication date: 2017.09.20

Summarized by Inyeol Yun

 

– Bioelectric Plaster (Fig. 1)
v. Wound healing on skin involves cell migration and proliferation in response to endogenous electric current.
v. External electrical stimulation is used to promote these biological processes for the treatment of chronic wounds.
v. An enzymatic biofuel cell (EBFC) that generates ionic current along the surface of the skin by enzymatic electrochemical reactions for more than 12h. (Fig. 2)

fig1

Fig. 1

fig2.png

Fig. 2

 

– Materials
v. Cathode : carbon fiber fabric coated with carbon nanotubes, on which reducing enzyme bilirubin oxidase
v. Anode : carbon fiber fabric coated with carbon nanotubes, on which oxidizing enzyme fructose dehydrogenase
v. Hydrogel : citrate buffer solutions with different concentrations of fructose.
v. Stretchable resistor : PEDOT/PU film

 

– Result
v. Time-dependent current changes of the bioelectric plaster with different external resistances and citrate buffer solutions with different concentrations. (Fig. 3)
v. Changes of wound width and height of Group A (gray), Group B (red), and Group C (blue) (Fig. 4)
v. Microscopy images of skin sections at the wound at day 7: a) the boundary between normal tissue and healed tissue, b) the area of normal tissue, c) the area of healed tissue, d) dermis, e) fat tissue (Fig. 5)  Group C > Group A on scar after healing, wound closure speed.

fig3

Fig. 3

fig4

Fig. 4

fig5.png

Fig. 5

 

– Reference
v. https://en.wikipedia.org/wiki/Enzymatic_biofuel_cell (accessed September 26, 2017)

Top Down Fabrication Meets Bottom-up Synthesis for Nanoelectronic Barcoding of Micro Particles

Journal: Lab on a chip

Publication date: 2017. 06

Summarized by Jinpyeo Jeung

 

– Nanoelectrically barcoded micro particles (Fig. 1)

v. Could be used in biomarker based diagnostics

v. Allows miniaturization of the readout instrument thus suitable for wearable device

v. Structure similar to Janus microparticles (JPs)

v. Polystyrene bead (3μm diameter), gold (20nm), Aluminium oxide (5nm, 20nm)

v. Due to difference in capacitance of bead, shows different frequency response (Fig. 2)

fig1.png

Fig. 1

fig2.png

Fig. 2

 

– Fabrication (Fig. 3)

v. Polystyrene microsphere self assembled onto a glass substrate using drop-casting

v. Wafer heated to evaporate liquid

v. Using electron beam evaporation, deposited gold layer

v. Using ALD, deposited an insulative layer

v. Particles lifted off from the film using ultrasonification

fig3.png

Fig. 3

 

– Result (Fig. 4)

v. 4 different bead could be distinguished by frequency response data

v. successful barcoding of micro particles

fig4.png

Fig. 4