BioChem Defense Technology (BCDT) develops 5H-EAF—an erythritol-capped linear penta-histidine nanochelant that activates at endosomal pH (5.5–6.5) and remains inert at physiologic pH (7.4). Public materials describe non-confidential science from ChemRxiv preprints, under dual-use stewardship.
Brand mark · BCDT
Positioning
5H-EAF is a reversible, pH-inverted histidine-rich nanochelant designed for electrostatic targeting of furin-processed polycationic species and free heavy metals (e.g., Cu²⁺ / Pb²⁺ class cations) at endosomal pH—while remaining low-activity at physiologic pH.
This public site presents only non-confidential science from open preprints: mechanism abstracts, computational validation summaries, and dual-use governance language. No controlled recipes, production protocols, or weaponization pathways.
Technology
High-level, non-confidential description of the published platform. Structural and computational detail lives in the ChemRxiv preprint (v6). Full computational packages remain under appropriate agreements.
Composition (public abstract)
01
At pH ~7.4 the platform remains in a lower-charge state—designed for safe circulation and controlled engagement outside acidic microenvironments.
02
At pH 5.5–6.5, histidine protonation drives a net +4 to +5 charge, enabling electrostatic clamping and metal coordination of polycationic species and free heavy-metal cations.
03
Return to neutral pH weakens binding for release and reagent recycling—supporting a protective, non-permanent capture paradigm rather than irreversible sequestration.
At acidic pH 5.5–6.5 the molecule protonates to a net charge of approximately +4 to +5, enabling strong electrostatic clamping and coordination. At neutral pH, bound species are released for safe clearance or reagent recycling. This reversible switch is the core of the published platform.
Active window
pH 5.5 – 6.5
Low-activity
pH ~7.4
Applications
Dual-use by nature: the same electrostatic / pH logic spans biodefense-relevant modeling and heavy-metal detoxification. Everything below is research framing, not product claims.
Computational evaluation of electrostatic engagement with furin-processed polycationic motifs and related endosomal architectures — framed as protective countermeasure research at the non-confidential abstract level.
pH-gated coordination of free cations (e.g., Pb²⁺ and related metals) with favorable binding free energies at acidic pH and reduced affinity at physiologic pH, as reported in open preprints.
Research framing connecting metal homeostasis (including ATP7A/ATOX1-related pathways), endosomal chemistry, and inflammatory stress — without clinical claims or treatment protocols.
DFT (B3LYP-D3/def2-TZVP) and all-atom MD / MM-PBSA used to quantify pH-dependent binding, reversibility, and multi-target electrostatic behavior across the published platform studies.
Science & data
This public site summarizes only the open ChemRxiv record (CC-BY) by Esteban A. Fridman, MD, PhD, BioChem Defense Technology. Preprints are not peer-reviewed; data may be preliminary. Full computational packages remain under appropriate agreements.
Canonical public platform paper (v6) — mechanism, heavy-metal detoxification, biodefense-relevant modeling.
Fridman EA. pH-Inverted Histidine-Rich Nanochelants for Trapping Furin-Processed Polycationic Nanotoxins. ChemRxiv. 2026. doi:10.26434/chemrxiv.15000714/v6 (preprint, CC-BY 4.0; not peer-reviewed).
doi:10.26434/chemrxiv.15000714/v6
https://chemrxiv.org/doi/full/10.26434/chemrxiv.15000714/v6What the public record supports
pH switchActive ~5.5–6.5; low activity ~7.4; reversible releaseCharge stateNet +4 to +5 when protonated (public abstract)Targets (abstract)Polycationic motifs · free heavy-metal cationsMethods (open)DFT · all-atom MD / MM-PBSA · multi-replica analysisDual-use stewardship
A platform that can inform biodefense research and metal detoxification is dual-use by definition. We treat that as a first-class design constraint—not a footnote.
Protective mission only
Public programs are oriented to health, environment, infrastructure resilience, and legitimate biodefense research—not offensive use.
Layered disclosure
Capability abstracts and preprint-level science publicly; sensitive implementation detail only under need-to-know agreements.
Partner diligence
Collaboration requests are screened for legitimate protective use and appropriate controls before deeper exchange.
Dual-use statement
We develop and discuss technology for identifying and reducing biological and chemical harm. We do not provide public guidance that would materially assist the creation, weaponization, or covert deployment of biological or chemical agents.
In scope (public)
Platform abstracts, pH-switch summary, preprint links, dual-use governance language, high-level applications.
Out of scope (public)
Agent production, weaponization steps, targeting doctrine, or export-controlled technical datasets.
Team
Founder · BioChem Defense Technology (BCDT) · Austin, TX
Physician-scientist leading computational and biophysical research on pH-gated histidine nanochelants. Corresponding author on the public 5H-EAF ChemRxiv preprints covering polycationic nanotoxin trapping and heavy-metal detoxification research. Prior training and research experience includes neuro / TBI-relevant clinical science; public materials emphasize protective mission and dual-use discipline.
Contact
For research collaboration, preprint discussion, dual-use review, or capability briefings limited to non-confidential scope.
Ideal partners: labs, public agencies, biodefense programs, and industry teams with a protective mission.
Do not send: controlled technical data, classified content, or detailed agent-production information via this form.
Direct: eafridman@biochemdefensetech.com