Origin of life's environments

Laboratory experiments have made remarkable progress in demonstrating the formation of biologically relevant building blocks. However, these reactions are typically performed under more or less idealized conditions—using pure starting materials, precise timing, and external manipulation.

Nature, by contrast, is messy. On the early Earth, no one was there to purify intermediates or orchestrate reaction steps in sequence. Most prebiotic reactions likely occurred in chemically complex, impure environments, where different compounds interacted simultaneously—both among themselves and with their physical environment. Yet, current experimental methods can rarely test these reactions in a shared setting, leaving a major gap in our understanding.

Most reactions yield a diverse mixture of compounds, especially when using impure starting materials. Moreover, these mixtures do not remain isolated from their dynamic physical environment. In addition, upstream conditions may differ significantly from downstream ones. Key questions arise:

• Are the side products of these reactions compatible with subsequent reactions?
• Can upstream products remain functional under downstream environmental conditions?
• What is the necessary degree of purification or enrichment of essential intermediates?
• What physical environmental forces—such as gradients, fluxes, and flow—play a role in prebiotic chemistry?
• What are the selectivity and mutual compatibility requirements of chemical mixtures for an effective transition from bio-monomers to functional biopolymers?

To address these questions, we are developing a modular flow reactor designed to simulate the more realistic and interconnected conditions of early Earth. Rather than isolating individual steps, this system allows multiple reactions to proceed in parallel under continuous flow—minimizing external manipulation and preserving the inherent natural complexity of the geochemical environment. By tuning the reactor to resemble different geochemical contexts, we can also explore how various natural settings might have shaped different prebiotic outcomes.

It is also important to appreciate that the early Earth was dynamic, and that certain transient conditions may have been even more productive than long-term stable ones.

• Can certain short-lived scenarios—such as post-impact reducing atmospheres—provide the necessary ingredients for prebiotic chemistry?
• How can we experimentally simulate such scenarios?

Of course, we cannot fully recreate Earth's early environments—much of the geological record is lost, and planetary-scale dynamics are not easy to be fully reproduced in the lab. But we can build simplified experimental environments that capture essential features and test how they influence prebiotic pathways, helping us build an evolving framework that becomes more refined as new chemical and geological insights emerge.

We envision this as an ever-evolving project with a one-of-a-kind apparatus. In building such a system, we will draw on concepts and technical expertise from various fields—including chemical engineering, geochemistry, and synthetic organic chemistry. Our aim is not only to understand how life may have begun on Earth, but also to identify the kinds of planetary environments elsewhere in the universe that might host similar prebiotic chemistries.