SUSTAINABLE BIOSENSOR · 2026

Bringing water safety to every remote community

AquaSense is an engineered E. coli biosensor for visual heavy-metal detection in the field — lab-grade sensitivity in 30 minutes, under $2 per test.

Project background ▶ 1-min video

Accuracy

▲ 12%

min

Time to result

▼ 96% vs lab

Cost per test

Survey samples

▲ 32%

01 · The Problem

Clear water is not always safe water

Millions rely on surface water with invisible heavy-metal contamination. Rural clinics often wait 3+ days for lab results.

We visited eight villages and found that test strips lack sensitivity while lab send-outs are slow and costly.

Core question: Can a community health worker with basic training run a valid heavy-metal screen in 30 minutes?

▲ August 2025 · community clinic interview

How we compare to existing methods

Field detection methods
Criteria	Test strips	Lab ICP-MS	AquaSense
Time to result	~15 min	3–5 days	30 min
Limit of detection (Pb²⁺)	~10 μM	~0.01 μM	0.12 μM
Field-ready	Yes	No	Yes

02 · Our Approach

Engineered microbes as living sensors

Four modules — switch tabs to explore each layer.

Metal-responsive promoters PzntA, PpbrA, PcadC — activated at 0.1 μM Pb²⁺/Cd²⁺.

T7 cascade amplifies binding events 100–500× for visible color change.

Dual AmilCP / AmilGFP channels report level and identity.

Auxotrophy + temperature-sensitive killswitch for biocontainment.

03 · Key Data

Experimental results

Four engineering iterations lowered LOD from 5 μM to 0.12 μM Pb²⁺.

Chart.js — line / area

ECharts — radar (project pillars)

Gel band comparison (before / after induction)

Before After

✎

Lab tip

Run 12 concentration gradients × 8 replicates in a 96-well plate — saves ~80% time vs tubes.

04 · Timeline

Six months of engineering

05 · Engineering

What we learned from failure

High background expression in negative controls

RBS too strong in v1. Switched to BBa_B0032 — background dropped 92%.

Signal drop at high metal concentration

Toxicity above 50 μM Pb²⁺. Added pulse-expression strategy for rapid reporter accumulation.

Loss of activity after drying

Trehalose + skim milk protectants — 87% activity after 30 days.

06 · Human Practices

Research in real context

If a tool is harder than a test strip, it never leaves the lab. AquaSense compromises at every step so it works at the wellside. — Ms. Amina Okoro, County environmental health officer

ECharts — HP engagement funnel

07 · Team