Electroactive Proteinoid-Quantum Dot Systems

Proteinoid-quantum dot (QD) conjugates are a new class of bioquantum hybrid materials combining biological self-assembly with semiconductor nanocrystal electronic properties. This study describes the synthesis and analysis of $\text{Glu}-\text{Phe}-\text{Asp}-\text{Cys}$ proteinoid-QD networks using sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (sulfo-SMCC) cross-linking chemistry, achieving 80-90% conjugation efficiency. Scanning electron microscopy reveals a morphological transformation from spherical precursors to toroidal nanostructures with outer diameters of $145.2\pm 18.7\hspace{0.17em}\text{nm}$ and central cavities of $102.3\pm 15.2\hspace{0.17em}\text{nm}$ . The hybrid networks exhibit spontaneous electrochemical oscillations ( $0.03$ to $0.11\hspace{0.17em}\text{Hz}$ , $297$ - $485\hspace{0.17em}\hspace{0.17em}\text{mV}$ ) reproducible across trials. QD incorporation enhances signal amplitude 41-fold ( $1999\hspace{0.17em}\hspace{0.17em}\text{mV}$ vs. $48.8\hspace{0.17em}\hspace{0.17em}\text{mV}$ ) via surface plasmon coupling. Optimal charge transfer resistance for biosensing is ≈ $5250\hspace{0.17em}\hspace{0.17em}\Omega$ . Electron transfer kinetics follow first-order decay ( $\alpha =0.0032\hspace{0.17em}\hspace{0.17em}{\text{Hz}}^{-1}$ ). The networks respond to structured binary input over 5 days, displaying frequency synchronization at $f=0.022217\hspace{0.17em}\hspace{0.17em}\text{Hz}$ . Magnitude-squared coherence values are $0.90$ for pure proteinoids and $0.85$ for conjugates. The system exhibits adaptive response-like behavior through structural transformations, enabling applications in neuromorphic computing, adaptive biosensors, and information processing architectures.