A Closed-Loop Chemical Reaction Network for Autonomous, Dual-Window Temporal Programming From a Single Fuel Pulse.

Area of Science:

• Chemical Engineering
• Materials Science
• Biomimetic Systems

Background:

• Living systems exhibit complex, multi-phase responses to single stimuli.
• Existing synthetic systems often lack autonomous, resettable, and programmable temporal control.

Purpose of the Study:

• To develop a closed-loop chemically fueled reaction network (CRN) that emulates life-like temporal programming.
• To achieve autonomous, multi-phase responses from a single fuel input with programmable control.

Main Methods:

• Utilized a CRN based on N-benzoyl-l-cysteine methyl ester-N-methylpiperazine dithiocarbamate (DTC).
• Employed dithiothreitol (DTT) as the fuel to trigger a sequence of chemical and physical transformations (Sol1 → Gel1 → Sol2 → Gel2 → Sol1).
• Investigated the role of pH and fuel reducing strength in controlling temporal gating and phase transitions.
• Combined experimental validation with kinetic modeling to confirm system behavior.

Main Results:

• Demonstrated a single fuel pulse (DTT) generating two temporally separated gel phases.
• Achieved autonomous cycling with molecular-level reset over >7 iterations.
• Showcased programmable temporal windows controlled by pH and fuel properties.
• Confirmed the hierarchical kinetic landscape's role in temporal gating and loop closure.

Conclusions:

• Developed a durable, resettable, and programmable platform for life-like dissipative functions.
• Successfully transitioned fuel-driven materials beyond single-event responses.
• Established a novel approach coupling closed-loop chemistry with temporal gating for advanced material functions.