Molecular design and characterization of the neuron-microelectrode array interface.
Electrophysiological activities of neuronal networks can be recorded on microelectrode arrays (MEAs). This technique requires tight coupling between MEA-surfaces and cells. Therefore, this study investigated the interface between DRG neurons and MEA-surface materials after adsorption of neurite promoting proteins: laminin-111, fibronectin, L1Ig6 and poly-l-lysine. Moreover, substrate-induced effects on neuronal networks with time were analyzed. The thickness of adsorbed protein layers was found between approximately 1 nm for poly-l-lysine and approximately 80 nm for laminin-111 on platinum, gold and silicon nitride. The neuron-to-substrate interface was characterized by Scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and SEM after in situ focused-ion-beam milling demonstrating that the ventral cell membrane adhered inhomogeneously to laminin-111 or L1Ig6 surfaces. Tight areas of 20-30 nm and distant areas <1 microm alternated and even tightest areas did not correlate with the physical thickness of the protein layers. This study illustrates the difficulties to predict cell-to-material interfaces that contribute substantially to the success of in vitro or in vivo systems. Moreover, focused ion beam (FIB)/SEM is explored as a new technique to analyze such interfaces.
Greve
Frauke
F
Physics Electronics Laboratory, Department of Physics, ETH Zurich, Switzerland.
Frerker
Susanne
S
Bittermann
Anne Greet
AG
Burkhardt
Claus
C
Hierlemann
Andreas
A
Hall
Heike
H
D000327:Adsorption; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002642:Chick Embryo; D005727:Ganglia, Spinal / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure; D008839:Microelectrodes; D009415:Nerve Net / Q000166:cytology / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D040081:Protein Array Analysis; D013499:Surface Properties