Improved electrical connections between neurons and electronic devices for human-device improved interface and for research
The ring-like Stable Protein 1 (SP1) is a homo-dodecamer with an outer diameter of 11nm and an inner pore of 3 nm. SP1 was recently proposed as a new self-assembled molecular scaffold for Nano biotechnology and biomaterials applications. Various SP1 derivatives can serve as a scaffold to display various protein domains attributing a cooperative effect to the resultant protein, forming enzymatic nanotubes
SP1 dissolves into the plasma membrane of living cells, leading to the generation of nano-pores and increasing of the membrane conductance.
Applying 1.8 nm gold nano-particles to the SP1 treats cells functionally plugs the inner pore, leading to the recovery of the membrane conductance.
FlexibiliSP1 can be covalently linked to various surfaces (such as gold, silicon oxide etc.)
This allows cells and sensing pads to electrically couple off, leading to the assembly of neuroelectronic hybrid systems.
6His-SP1 links to gold surfaces of microelectrodes and parts into the plasma membrane. Technology shows that forms of SP1 could generate controlled Ohmic coupling between sensing pads and excitable cells.
Fig. 2. wtSP1 induces membrane depolarization and decreased input resistance.
(a) Control neuron - the relationships between the input resistance and transmembrane potential was established by measuring the voltage drop in response to a constant rectangular current pulse injected into the neuron, while shifting the transmembrane voltage to various values by DC current. The value to which the membrane potential was set is indicated on the left-hand side. (b) The relations between Rin and the transmembrane potential in four control neurons. Rin was calculated from the voltage drop generated by a 2 sec long, 0.3 nA hyperpolarizing square pulls current injection. To evaluate directly the effects of wtSP1 on the transmembrane potential and Rin, wtSP1 (2 M) was applied to the bathing solution while the membrane potential and input resistance were measured (arrow, c). Note that approximately 10 min. after SP1 application the membrane depolarized and the input resistance was transiently elevated. Insert in c- representative traces of the recorded voltage drop in response to a constant rectangular current injection pulse before and 15 minutes after wtSP1 application. (d) Variability in the rate of SP1-induced membrane depolarization (n=5). (e) The effects of wtSP1 on membrane potential are reversible upon washes (dashed line) in 4 out of 6 experiments.
In combination with the formation of high seal resistance between the cells and the sensing pads and the controlled and localized functionalism of sensing pads, generation of Ohmic coupling between the interior of neurons and sensing pads of electronic devices is possible and sustainable.