Measurement changes the system — yet we often measure as if it does not
Electrochemistry was not built for biology. It was built for chemistry — for systems that can be forced, stabilized, and interrogated.
In chemistry, applying a signal is the method. In biology, it changes the system.
Electrochemical techniques like CV and EIS were designed to probe redox behavior under controlled conditions. You apply a voltage, observe a response, and interpret it. But a living system is not a passive material.
The moment you apply voltage or current, you are not just measuring — you are intervening. You introduce stress and alter the system itself. The data you get is no longer the native state; it reflects the system under influence.
That difference is not small. It defines the limit of what you can trust.
Many electrochemical methods in biology rely on biofilm formation. It creates a stable interface and makes measurement easier. But in real processes — especially fermentation — biofilm is often not what we want, and sometimes actively harmful.
More importantly, biofilm creates its own system. The interface becomes something we don’t fully control. The measurement shifts toward that interface, not the original system.
We think we are measuring biology. We are often measuring what we forced it to become.
In chemistry, the probe is assumed to be neutral. In biology, it is not. Different bacteria respond differently to electrodes — some attach, some don’t, some transfer electrons efficiently, others do not interact at all — and material, surface, and geometry all shape the response.
The electrode is no longer a tool. It becomes part of the system — and the measurement is no longer independent.
We cannot abandon electrochemistry. For many biological systems — especially electroactive bacteria — electron transfer is not optional. It is how the system functions. If we remove electrical measurement, we lose one of the few direct signals of system state. Without signal, we are blind.
So we compensate.
We measure pH, metabolites, optical density. We isolate cells, use microfluidics, and simplify the system until it becomes measurable. But each of these steps moves us further from reality. We create conditions that are easier to observe, but less representative of how the system actually behaves.
It is like monitoring a patient only when they reach the ICU — the signal becomes clear, but too late.
Direct methods distort the system in real time, while indirect methods preserve accuracy but lose the signal when it matters. That gap is where understanding breaks.
Biological systems are nonlinear, adaptive, and context-dependent. They don’t respond predictably to forced inputs — which is exactly what these methods rely on. Today, we have better tools: data processing, AI, and pattern recognition. We can handle complexity better than before.
Better models cannot fix broken measurement.
The problem is not electrochemistry itself — it is how we use it. We don’t need to remove signal — we need to stop forcing it.
We need methods that capture electrical activity without disturbing the system, operate under real conditions rather than simplified ones, and provide continuous insight instead of delayed snapshots. We need to move from forcing responses to observing behavior, and from imposing signals to interacting with the system as it is.
The limitation is not that biology is too complex. It is that we are still trying to measure it with tools built for something simpler. Until that changes, we will keep generating data — and still not understand the system producing it.
— Pegah Farr