01
ISF is not blood.
Each analyte gets its own evidence, lag, calibration, and claim. No universal conversion turns a patch into a lab panel.
Continuous biochemical monitoring platform · Research stage
Continuous chemistry.Honest uncertainty.
CBM G1 is a sourced, open-hardware research platform for interstitial-fluid sensing: six target chemistries, two quality-control channels, and a system designed to stop reporting when the measurement stops earning trust.
8Modular sensor tiles
12Dry contacts
2×3Needles per tile
0Treatment claims
Nominal mechanical fit · PassThe actual Biocoin STEP drives twelve clearance and connector-stack checks.
Product outside · Engineering insideOpen the cutaway to see every board, retainer, harness, gasket, and contact.
01 — Governing principles
Measure less. Know more.
CBM starts with the errors that can fabricate a plausible number, then designs the hardware, controls, and public claims around exposing them.
02
Leakage is signal.
Five picoamps across a gigaohm membrane becomes five millivolts—roughly the entire potassium move from 5 to 6 mmol/L.
03
Area is reliability.
A six-needle tile approaches the active area of the bench electrode and does not let one missed insertion erase a channel.
04
Null is an output.
Raw data are retained, but a failed reference, blank, duplicate, contact, or calibration gate yields no interpreted value.
02 — Why build it
The case is not more data. It is fewer blind intervals.
No patient needs to rely on this unvalidated device today. The public-interest case is conditional: a trustworthy trend must trigger earlier confirmation, that confirmation must change care, and the changed care must improve an outcome that matters.
Utilitarian verdict
Build the shared measurement platform and narrow clinical programs—not a universal wellness patch.
Its clearest near-term contribution to human flourishing is as open translational infrastructure: one reusable instrument that lets research and clinical teams test several chemistries without designing a new reader for each one. Its largest potential patient benefit comes later, in high-risk populations where chemistry changes faster than scheduled testing and a trend has a predefined confirmatory action.
~47%Estimated share of the world without access to essential diagnostic testing. CBM cannot close this alone; it must fit a tiered diagnostic network.
46.5%Eligible HFrEF patients without a serum potassium check within 7 days after MRA initiation in a multicenter cohort.
5 minResolution in a six-person 2026 human vancomycin microneedle pilot; degradation limited the primary analysis to the first 12 hours.
0Populations who should use the present research device for diagnosis, dosing, or emergency decisions.
Highest present utility · Build now
Translational research teams.
Who needs it: university, hospital, and public-interest biosensor groups that otherwise duplicate reader electronics before testing chemistry. Open hardware, raw traces, interchangeable tiles, and shared validation methods can make this a scientific public good.
High conditional utility · Validate
Time-sensitive, high-risk care.
Who may benefit: diabetes/DKA, CKD or heart-failure medication titration, dialysis, acute-care lactate surveillance, and narrow-therapeutic-window drug dosing. Glucose+ketone already has a commercial incumbent; added value must come from validated additional channels or a better workflow—not novelty alone.
Distribution utility · Integrate
Clinic and bedside networks.
Best distributed form: reusable readers in clinics, step-down units, research hospitals, and regional programs with local cartridges, trained operators, quality control, and referral labs. WHO guidance is explicit: decentralized tests create value only inside financed, quality-assured diagnostic networks.
Low or negative utility · Do not target
Continuous testing for everyone.
Who does not need it: healthy people without a defined action for each result. Broad deployment would add false alarms, false reassurance, surveillance, medicalization, cost, and disposable waste. Existing CGM use already generates large packaging and electronic-waste streams.
01 · Valid signalAnalytical accuracy, wear stability, reference control, and an honest null state.
02 · Earlier confirmationThe trend advances a laboratory check or clinician review rather than replacing it.
03 · Changed careA clinician adjusts monitoring, medication, fluids, dialysis, or dosing sooner.
04 · Human outcomeLess harm, fewer burdensome draws or trips, preserved effective therapy, or better survival and function.
How it could promote flourishing
Earlier detection for fragile patients; fewer avoidable venipunctures and trips; more autonomy between visits; preservation of beneficial therapy; and wider research capacity through open, reusable instrumentation.
How it could reduce flourishing
Bad signals can provoke overtreatment or false reassurance. Continuous biochemical surveillance can erode privacy and turn normal variation into illness. Disposable cartridges consume materials and clinical attention that may produce more benefit elsewhere.
03 — System architecture · assembled at real scale
One reader. Eight wet laboratories.
The reusable puck owns measurement modes and data integrity. The disposable cartridge owns every tissue-contact material, sensing chemistry, reference, counter, lot, and calibration.
Reusable envelope
Ø44 × 19.0Actual populated Biocoin, 38 mm daughterboard, cradle, harness, and retainers.
Disposable field
8 × 6 needlesEight isolated tiles on a 32 mm open sensing field.
Dry interface
12 @ 2.54One retained Mill-Max 817 connector at 2.24 mm working height.
Fit status
12 / 12 passNominal STEP-backed clearance checks; unresolved tests stay named.
04 — G1 cartridge
Six targets. Two witnesses.
The panel spans mediated enzyme and ion-selective sensing without pretending every channel has the same maturity.
WE1 · enzyme
Glucose
Prussian Blue + GOx. Commercial anchor and system sanity reference.
Commercial precedent
WE2 · enzyme
β-hydroxybutyrate
HBD/NAD+/poly-TBO stack. The strongest reason to measure beyond glucose.
CE product + human pilots
WE3 · enzyme
Lactate
LOx-mediated research lane with human microneedle precedent and analyte-specific lag.
Human pilot
WE4 · control
Glucose duplicate
Separate deposition lane exposes missed insertion and lane-specific coating failure.
Quality control
WE5 · ISE
Sodium
PEDOT:PSS + ionophore X. Electrolyte context and common-mode reference witness.
Animal multi-panel
WE6 · ISE
Potassium
Valinomycin membrane. Highest-value and least-forgiving quantitative research lane.
Bench + usability evidence
WE7 · ISE
pH
Polyaniline starting route. Context for chemistry, junction behavior, and drift.
Animal multi-panel
WE8 · control
Background blank
A nonspecific electrochemical sentinel—not a magical universal correction.
Quality control
05 — The build order
Prove the chemistry. Then buy the needles.
G0 and G1 are separate so a coating mistake cannot hide inside a custom wearable, and an enclosure cannot be mistaken for a sensor.
G0 · catalog bench
Eight independent gold cells.
PalmSens drives amperometry and deposition. A guarded electrometer path owns high-impedance truth. Every chemistry earns its own ladder, interference matrix, drift record, and induced-fault result.
01Electrical loading fixture: 10 MΩ → 1 GΩ
02DRP-8X220AT: eight complete 3-electrode cells
03Three independent arrays before reproducibility claims
G1 · custom research wearable
Open reader. Integrated wet end.
The published Biocoin PCB survives intact and mates through its own docking pads. Custom work is limited to the guarded interface board, retained cartridge, sensor tiles, seals, and enclosure.
01RFQ only after electrical, chemistry, and quality gates pass
02Inert mechanical cartridge before functional coatings
03No on-body step without approved governance
06 — What must be custom
Six systems. Every interface named.
The build book carries the dimensions, materials, process windows, source method, and acceptance test for each custom item.
CP-01 · PCB
Guarded interface board
38 mm full disc with six LMP7721 islands, ADS124S08, four upstream-exact dock headers, and the retained 12-contact connector.
Open specification →CP-02 · Microfabrication
2×3 sensor tiles
Published PS/PDMS mold route: 1.0 mm needles, 10 nm Cr, 150 nm Au, plus dimensional, insertion, and coating QC.
Open specification →CP-03 · RFQ alternate
316L metal tiles
Nickel-free gold-coated 30–36G vendor route with isolation, pinhole, corrosion, coating, and traceability requirements.
Open specification →CP-04 · Flex
Twelve-net interposer
25 µm polyimide core, eight tile landings, two references, CE, hard-gold dry boss, and no exposed wet-side nickel or copper.
Open specification →CP-05 · Electrochemical
Reference pair + counter
Separately fabricated Ag/AgCl reservoirs and central Pt counter, released by drift and compliance—not color or geometry.
Open specification →CP-07 · Conversion
Barrier, gasket, adhesive
ARcare 7759 passivation, converted 4077 skirt, dry-field ingress barrier, keyed stop, and assembly-level biological evaluation.
Open specification →07 — Frontier, correctly labeled
The latest work is real. Its limits are too.
Commercial, human, animal, and engineering evidence answer different questions. G1 keeps those labels attached.
Libre Duo
Glucose + ketone every minute; up to 15 days. Not cleared in the United States.
Abbott · May 2026 ↗Biocoin
26 mm multimodal AD5940+nRF52840 platform with published hardware, firmware, software, and STEP.
npj Biosensing · 2026 ↗eMPatch
Six simultaneous analytes in rats; modular 2×3 tiles. Continuous stability: 120 minutes in artificial ISF.
Nano-Micro Letters · 2026 ↗Adaptyx cortisol
Eight target + eight control channels; n=3 challenge and n=3 overnight. Promising, not cleared.
Diabetes · 2026 ↗Ketone RCT
Seven people over 14 days; dynamics captured, progressive decline consistent with sensor drift.
JMIR Diabetes · 2026 ↗Hard boundary
CAD is not clearance.
A functional microneedle cartridge does not go from artificial ISF to a self-test. Human research requires IRB review, the appropriate IDE or nonsignificant-risk determination, informed consent, final-assembly biological evaluation, sterilization and packaging evidence, electrical safety, comparators, and stop rules.
Not claimedDiagnosis, dosing, emergency alerts, serum equivalence.
Not inheritedOne supplier's biocompatibility statement is not device safety.
Not automaticA passed bench gate never authorizes skin wear.
Everything inspectable
Rotate the assembly. Audit the sources. Build only what the evidence unlocks.
The interactive model exposes each sourced and custom part. The build book carries the BOM, custom-part process, material sources, validation gates, and downloadable CAD.