Silk and PEG as means to stiffen a parylene probe for insertion in the brain: toward a double time-scale tool for local drug delivery

Aziliz Lecomte; Valentina Castagnola; Emeline Descamps; Lionel Dahan; Marie-Charline Blatché; Tony Dinis; Eric Leclerc; Christophe Egles; Christian Bergaud

doi:10.1088/0960-1317/25/12/125003

Silk and PEG as means to stiffen a parylene probe for insertion in the brain: toward a double time-scale tool for local drug delivery

Aziliz Lecomte ¹ Valentina Castagnola ¹ Emeline Descamps ² Lionel Dahan ³ Marie-Charline Blatché ⁴ Tony Dinis ⁵ Eric Leclerc ⁵ Christophe Egles ⁵ Christian Bergaud ¹

1 LAAS-MEMS - Équipe Microsystèmes électromécaniques

LAAS - Laboratoire d'analyse et d'architecture des systèmes

2 LAAS-MICA - Équipe MICrosystèmes d'Analyse

LAAS - Laboratoire d'analyse et d'architecture des systèmes

3 CRCA - Centre de Recherches sur la Cognition Animale

4 LAAS-I2C - Service Instrumentation Conception Caractérisation

LAAS - Laboratoire d'analyse et d'architecture des systèmes

5 BMBI - Biomécanique et Bioingénierie

Abstract : The use of soft materials as substrate for neural probes aims at achieving better compliance with the surrounding neurons while maintaining minimal rejection. Many strategies have emerged to enable such probes to penetrate the cortex, among which the use of resorbable polymers. We performed several tests involving two resorbable polymers considered most promising: polyethylene glycol (PEG) and silk fibroin (SF) from Bombyx Mori silkworms. Our coating method provides a repeatable, uniform structure optimized for a stress-reduced insertion of a parylene-C neural probe. Standard compression tests as well as in vitro and in vivo insertion assessments show that both SF and PEG-coated probes are stiff enough to avoid the buckling effect during insertion in the cortex. However, with a buckling force of 300 mN and a mechanical holding in vitro of tens of minutes, we assess silk fibroin to be more reliable for practical handling. In vivo first try-outs in mouse brain showed neither buckling issues of the probe nor undesired alteration of the signal recording. Moreover, we evidenced two distinct time scales in the bioresorption of our polymer coatings: silk fibroin degrades itself in a matter of weeks and PEG dissolves itself within seconds in the presence of water. We then present a hybrid PEG and SF coating that could be used as a drug delivery system with different time scales to reduce both the acute and the chronic body reaction.

Document type :

Journal articles

Domain :

Engineering Sciences [physics] / Micro and nanotechnologies/Microelectronics

Complete list of metadatas

https://hal.laas.fr/hal-01764281
Contributor : Christian Bergaud <>
Submitted on : Wednesday, April 11, 2018 - 5:55:29 PM
Last modification on : Friday, January 10, 2020 - 9:10:19 PM

Silk and PEG as means to stiffen a parylene probe for insertion in the brain: toward a double time-scale tool for local drug delivery

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Silk and PEG as means to stiffen a parylene probe for insertion in the brain: toward a double time-scale tool for local drug delivery

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