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pHEMA Encapsulated PEDOT-PSS-CNT Microsphere Microelectrodes for Recording Single Unit Activity in the Brain.

Castagnola E, Maggiolini E, Ceseracciu L, Ciarpella F, Zucchini E, De Faveri S, Fadiga L, Ricci D - Front Neurosci (2016)

Bottom Line: This enhancement significantly reduces the size of the implantable device though preserving excellent electrical performances.Moreover, the spherical shape of the electrode together with the surface area increase provided by the nanocomposite deposited on it, maximize the electrical contact and may improve recording stability over time.These results have a good potential to contribute to fulfill the grand challenge of obtaining stable neural interfaces for long-term applications.

View Article: PubMed Central - PubMed

Affiliation: Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia Ferrara, Italy.

ABSTRACT
The long-term reliability of neural interfaces and stability of high-quality recordings are still unsolved issues in neuroscience research. High surface area PEDOT-PSS-CNT composites are able to greatly improve the performance of recording and stimulation for traditional intracortical metal microelectrodes by decreasing their impedance and increasing their charge transfer capability. This enhancement significantly reduces the size of the implantable device though preserving excellent electrical performances. On the other hand, the presence of nanomaterials often rises concerns regarding possible health hazards, especially when considering a clinical application of the devices. For this reason, we decided to explore the problem from a new perspective by designing and testing an innovative device based on nanostructured microspheres grown on a thin tether, integrating PEDOT-PSS-CNT nanocomposites with a soft synthetic permanent biocompatible hydrogel. The pHEMA hydrogel preserves the electrochemical performance and high quality recording ability of PEDOT-PSS-CNT coated devices, reduces the mechanical mismatch between soft brain tissue and stiff devices and also avoids direct contact between the neural tissue and the nanocomposite, by acting as a biocompatible protective barrier against potential nanomaterial detachment. Moreover, the spherical shape of the electrode together with the surface area increase provided by the nanocomposite deposited on it, maximize the electrical contact and may improve recording stability over time. These results have a good potential to contribute to fulfill the grand challenge of obtaining stable neural interfaces for long-term applications.

No MeSH data available.


Related in: MedlinePlus

Fluorescence microscopy images of tracks for non-encapsulated (left panels) and pHEMA-encapsulated (right panels) microspheres at 2 weeks after implant. (A,B) show the GFAP-positive cells (red) at 40 × to underline the morphology of astrocytes; (C,D) cell nuclei (blue) merged on GFAP staining to show the density of DAPI surrounding tracks; (E,F) neuronal nuclei (green) merged with GFAP staining to show the presence of neuronal bodies surrounding the track.
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Figure 9: Fluorescence microscopy images of tracks for non-encapsulated (left panels) and pHEMA-encapsulated (right panels) microspheres at 2 weeks after implant. (A,B) show the GFAP-positive cells (red) at 40 × to underline the morphology of astrocytes; (C,D) cell nuclei (blue) merged on GFAP staining to show the density of DAPI surrounding tracks; (E,F) neuronal nuclei (green) merged with GFAP staining to show the presence of neuronal bodies surrounding the track.

Mentions: In the 2-weeks implanted animals the levels of GFAP for both non-encapsulated and pHEMA encapsulated PEDOT-PSS-CNT microspheres (Figures 9A,B) were similar, with 43.84% and 42.91% of intensity compared to the background, respectively. The activated astrocytes presented the same extension in surrounding tracks for both type of microelectrodes (28–135 μm for non-encapsulated and 29–141 μm encapsulated ones). After 4 weeks of implant GFAP expression (Figures 10A,B) increased by 28.95% with respect to the background with non-encapsulated microspheres and by 37.69% with pHEMA-encapsulated ones. GFAP staining surrounding the tracks was 15–150 μm for non-encapsulated and 10–100 μm for pHEMA-encapsulated microspheres.


pHEMA Encapsulated PEDOT-PSS-CNT Microsphere Microelectrodes for Recording Single Unit Activity in the Brain.

Castagnola E, Maggiolini E, Ceseracciu L, Ciarpella F, Zucchini E, De Faveri S, Fadiga L, Ricci D - Front Neurosci (2016)

Fluorescence microscopy images of tracks for non-encapsulated (left panels) and pHEMA-encapsulated (right panels) microspheres at 2 weeks after implant. (A,B) show the GFAP-positive cells (red) at 40 × to underline the morphology of astrocytes; (C,D) cell nuclei (blue) merged on GFAP staining to show the density of DAPI surrounding tracks; (E,F) neuronal nuclei (green) merged with GFAP staining to show the presence of neuronal bodies surrounding the track.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834343&req=5

Figure 9: Fluorescence microscopy images of tracks for non-encapsulated (left panels) and pHEMA-encapsulated (right panels) microspheres at 2 weeks after implant. (A,B) show the GFAP-positive cells (red) at 40 × to underline the morphology of astrocytes; (C,D) cell nuclei (blue) merged on GFAP staining to show the density of DAPI surrounding tracks; (E,F) neuronal nuclei (green) merged with GFAP staining to show the presence of neuronal bodies surrounding the track.
Mentions: In the 2-weeks implanted animals the levels of GFAP for both non-encapsulated and pHEMA encapsulated PEDOT-PSS-CNT microspheres (Figures 9A,B) were similar, with 43.84% and 42.91% of intensity compared to the background, respectively. The activated astrocytes presented the same extension in surrounding tracks for both type of microelectrodes (28–135 μm for non-encapsulated and 29–141 μm encapsulated ones). After 4 weeks of implant GFAP expression (Figures 10A,B) increased by 28.95% with respect to the background with non-encapsulated microspheres and by 37.69% with pHEMA-encapsulated ones. GFAP staining surrounding the tracks was 15–150 μm for non-encapsulated and 10–100 μm for pHEMA-encapsulated microspheres.

Bottom Line: This enhancement significantly reduces the size of the implantable device though preserving excellent electrical performances.Moreover, the spherical shape of the electrode together with the surface area increase provided by the nanocomposite deposited on it, maximize the electrical contact and may improve recording stability over time.These results have a good potential to contribute to fulfill the grand challenge of obtaining stable neural interfaces for long-term applications.

View Article: PubMed Central - PubMed

Affiliation: Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia Ferrara, Italy.

ABSTRACT
The long-term reliability of neural interfaces and stability of high-quality recordings are still unsolved issues in neuroscience research. High surface area PEDOT-PSS-CNT composites are able to greatly improve the performance of recording and stimulation for traditional intracortical metal microelectrodes by decreasing their impedance and increasing their charge transfer capability. This enhancement significantly reduces the size of the implantable device though preserving excellent electrical performances. On the other hand, the presence of nanomaterials often rises concerns regarding possible health hazards, especially when considering a clinical application of the devices. For this reason, we decided to explore the problem from a new perspective by designing and testing an innovative device based on nanostructured microspheres grown on a thin tether, integrating PEDOT-PSS-CNT nanocomposites with a soft synthetic permanent biocompatible hydrogel. The pHEMA hydrogel preserves the electrochemical performance and high quality recording ability of PEDOT-PSS-CNT coated devices, reduces the mechanical mismatch between soft brain tissue and stiff devices and also avoids direct contact between the neural tissue and the nanocomposite, by acting as a biocompatible protective barrier against potential nanomaterial detachment. Moreover, the spherical shape of the electrode together with the surface area increase provided by the nanocomposite deposited on it, maximize the electrical contact and may improve recording stability over time. These results have a good potential to contribute to fulfill the grand challenge of obtaining stable neural interfaces for long-term applications.

No MeSH data available.


Related in: MedlinePlus