# Thermosensory Spiking Activity of Proteinoid Microspheres Cross-Linked by Actin Filaments

## TL;DR

This paper explores how proteinoid microspheres combined with actin filaments can generate voltage spikes and brain-like signaling without membranes or ion channels.

## Contribution

The study introduces hybrid actin-proteinoid networks that exhibit stable, life-like signal encoding and improved coordination in synthetic protocell systems.

## Key findings

- Proteinoid microspheres produce voltage spikes and brain-like excitation dynamics without membranes or ion channels.
- Adding actin filaments reduces spike timing variability and enhances coordination in hybrid networks.
- Temperature changes regulate conduction states, enabling external control over emergent excitability in protobrain systems.

## Abstract

Actin, found in all
eukaryotic cells as globular (G) or filamentous
(F) actin, undergoes polymerization, with G-actin units changing shape
to become F-actin. Thermal proteins, or proteinoids, are created by
heating amino acids (160–200 °C), forming polymeric chains.
These proteinoids can swell in an aqueous solution at around 50 °C,
producing hollow microspheres filled with a solution, exhibiting voltage
spikes. Our research explores the signaling properties of proteinoids,
actin filaments, and hybrid networks combining actin and proteinoids.
Proteinoids replicate brain excitation dynamics despite lacking specific
membranes or ion channels. We investigate enhancing conductivity and
spiking by using pure actin, yielding improved coordination in networks
compared with individual filaments or proteinoids. Temperature changes
(20 short-peptide supramolecular C to 80 °C) regulate conduction
states, demonstrating external control over emergent excitability
in protobrain systems. Adding actin to proteinoids reduces spike timing
variability, providing a more uniform feature distribution. These
findings support theoretical models proposing cytoskeletal matrices
for functional specification in synthetic protocell brains, promoting
stable interaction complexity. The study concludes that life-like
signal encoding can emerge spontaneously within biological polymer
scaffolds, incorporating abiotic chemistry.