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Colorimetric Oligos for Lateral Flow & Plate Assays (AuNP • Biotin • HRP/AP)

Build robust color readouts in plates, strips, and paper devices. We provide HRP/AP enzyme-labeled oligos, biotin/DIG/DNP haptens, AuNP coupling via thiols, redox labels (methylene blue, ferrocene), and G-quadruplex DNAzyme designs—delivered with full QC.

HRP / AP Enzyme Oligos Biotin / DIG / DNP Haptens Gold Nanoparticles (AuNP) Redox & Chromogenic Labels DNAzyme (Hemin–G4)

Overview

Bio-Synthesis engineers colorimetric oligonucleotides for rapid, equipment‑light readouts in lateral flow assays (LFA), paper microfluidics, and ELISA‑like plates. Build gold nanoparticle (AuNP) DNA probes via thiol coupling, specify biotinylated oligonucleotides for streptavidin capture lines, select HRP/AP enzyme‑labeled oligos for chromogenic substrates (TMB/ABTS; pNPP/BCIP‑NBT), or use DNAzyme (hemin–G4) and redox tags (methylene blue, ferrocene, anthraquinone) for enzyme‑free or hybrid electro‑/colorimetric detection—delivered with full QC.

Formats
Tubes • 96-well plates
Scale
µmol → multi-gram
QC
UPLC/HPLC • LC-MS
Supply
RUO → GMP-like

Also searched as: lateral flow nucleic‑acid assay, AuNP DNA probe, biotinylated oligo (streptavidin), enzyme‑labeled oligo, DNAzyme colorimetric oligo, methylene blue oligo.

Products & Notes

Product / Modification Description Typical use Code
HRP-Oligo (direct conjugate) Horseradish peroxidase linked to DNA/RNA. Plate assays, LFA reporter; TMB/ABTS substrates. [HRP]
AP-Oligo (direct conjugate) Alkaline phosphatase linked to DNA/RNA. Plate/LFA reporter; pNPP or BCIP/NBT substrates. [AP]
Biotin-dT / 5′-Biotin / Dual Biotin High-affinity capture via streptavidin. SA-HRP/AP detection; capture lines in LFA. [Bio-dT], [5′-Bio]
DIG-labeled Oligo Digoxigenin hapten tag. Anti-DIG-HRP/AP detection; multiplex with biotin. [DIG]
DNP-labeled Oligo Dinitrophenyl hapten tag. Anti-DNP detection; orthogonal to DIG/biotin. [DNP]
Fluorescein (FITC) Hapten Fluorescein tag for anti-FITC capture. LFA test lines; anti-FITC-gold or HRP/AP routes. [FITC]
Technical Notes
  • HRP substrates: TMB (blue, ~652 nm) or ABTS (green); stop solutions shift absorbance for endpoint reads.
  • AP substrates: pNPP (yellow, 405 nm) or BCIP/NBT (insoluble purple precipitate for blots/strips).
  • Haptens enable flexible supply chains: use anti-hapten-HRP/AP or streptavidin-HRP/AP interchangeably.

Product / Modification Description Typical use Code
5′-Thiol / 3′-Thiol Terminal sulfhydryl for Au–S coupling. AuNP probes; surface immobilization. [5′-SH], [3′-SH]
Dithiol Linker (C6 S-S) Disulfide protected thiol; reduce before coupling. Stable storage, then on-demand AuNP conjugation. [SS-C6]
Thiol-dT (internal) Thiol within the sequence. Multisite AuNP attachment or surface anchoring. [Thiol-dT]
5′-Amine / 3′-Amine Primary amine for NHS-activated surfaces. Plate coupling, beads, or Au coatings via linkers. [5′-NH2], [3′-NH2]
Biotinylated Oligo For SA-coated gold or capture lines. LFA capture/detection with SA-gold or SA-HRP. [Biotin]
Technical Notes
  • Salt-aging and surfactants (e.g., Tween-20) help stabilize AuNP-oligo conjugates and minimize aggregation.
  • Spacer (TEG/PEG/Sp18) between the thiol and probe region improves accessibility and color response.
  • Silver enhancement can amplify visual lines; time carefully to balance sensitivity and background.

Product / Modification Description Typical use Code
Methylene Blue (MB) Blue chromophore; also electroactive. Color/electro-readouts; beacon probes. [MB]
Ferrocene (Fc) Organometallic redox tag. Electrochromic or hybrid color assays. [Fc]
Anthraquinone (AQ) Redox-active polycyclic tag. Electro-assays with visual confirmation. [AQ]
Technical Notes
  • Place redox tags on short flexible linkers to reduce quenching and steric hindrance.
  • Balance label position (end vs internal) with hybridization stability and Tm.

Product / Modification Description Typical use Code
G-Quadruplex Scaffold Oligo Custom G-rich sequences optimized for hemin binding. Enzyme-free color development with TMB/ABTS. [G4-Scaffold]
Spacer Integration (TEG/PEG) Improves folding and substrate access. Boosts signal & reduces crowding on surfaces. [Spacer-TEG]
Hemin Cofactor Support Procurement/handling guidance for assays. Enable peroxidase-like activity in solution or on strip. [Hemin-Assist]
Technical Notes
  • Tune K+/Na+ and pH for G4 stability; add spacers to minimize surface interference.
  • Pre-form G4/hemin complexes as needed; protect from light.

Product / Modification Description Typical use Code
Sp18 / HEG 18-atom hexaethylene glycol spacer. Reduce sterics near labels/enzymes. [Sp18], [HEG]
PEG Linkers (various) Hydrophilic flexible linkers. Improve solubility and binding kinetics. [PEG-n]
Abasic Site (dSpacer) Non-coding spacer within sequence. Geometry tuning for probe architectures. [dSpacer]
Technical Notes
  • For HRP/AP or bulky haptens, place a spacer between the tag and the hybridization region.
  • For AuNP probes, a short spacer after the thiol often improves dispersion and signal.
Explore related chemistries
Services at a glance
  • Custom design review
  • RUO → GMP-like production
  • QC: UPLC/HPLC, LC-MS
Need help choosing the best colorimetric route?

We’ll recommend the optimal reporter (HRP/AP, AuNP, DNAzyme, redox), spacers, and substrates for your matrix.

Speak to a Scientist

Design • Chemistry • Applications

Design Strategy
  • Choose the system: HRP/AP (plate/LFA), AuNP (visible color shift), DNAzyme (enzyme-free), or redox labels.
  • Capture planning: biotin–streptavidin, DIG/DNP/fluorescein antibody capture, or thiol→Au for probes.
  • Spacer & sterics: add TEG/PEG/Sp18 near enzymes/haptens to reduce crowding and improve binding.
  • Signal tuning: substrate choice (TMB/ABTS for HRP; pNPP/BCIP/NBT for AP), AuNP size, or DNAzyme conditions.
  • Controls: no-template and non-complement controls to confirm specificity; include a capture-only control line in LFAs.
Chemistries
  • Enzyme conjugates: HRP, AP; hapten tags (biotin, DIG, DNP, fluorescein).
  • AuNP coupling: 5′/3′-Thiol, dithiol (S-S) modifiers; amine→NHS surfaces; silver enhancement optional.
  • Redox/chromogenic labels: methylene blue (MB), ferrocene (Fc), anthraquinone (AQ).
  • DNAzyme (hemin–G4): G-rich scaffolds with hemin cofactor for peroxidase-like activity.

Popular spacers: TEG/PEG, Sp18/HEG; end caps: 3′-phosphate/3′-deoxy to prevent extension where needed.

Applications
  • Plate assays (ELISA-like), LFA/paper devices, dot-blot/spot assays.
  • Target detection via sandwich / competitive formats.
  • AuNP aggregation color shift; silver amplification for sensitivity.
  • Enzyme-free color readouts with DNAzymes (TMB/ABTS).
  • Multiplex with orthogonal haptens (e.g., biotin + DIG) or spatially separated lines.

FAQ

HRP or AP—how do I choose?

HRP is fast and works with TMB/ABTS; AP is stable for long incubations and pairs with pNPP or BCIP/NBT. Pick based on matrix, timing, and whether you want soluble or precipitating products.

What substrates are recommended?

  • HRP: TMB (blue, ~652 nm) or ABTS (green). Optional stop to shift to a stable endpoint.
  • AP: pNPP (yellow, 405 nm) or BCIP/NBT (insoluble purple for blots/strips).

How do I attach oligos to gold nanoparticles?

Use 5′/3′-thiol or protected dithiol modifiers, deprotect if needed, then salt-age onto AuNP with surfactant (e.g., Tween-20). Add short spacers to improve dispersion and accessibility.

Can I multiplex colorimetric assays?

Yes—use orthogonal haptens (biotin, DIG, DNP, fluorescein) or spatially separated lines/spots. Balance probe Tm and spacer length to limit cross-talk.

Do you provide enzyme-conjugation and LFA assembly?

Yes—direct HRP/AP conjugation, hapten labeling, and AuNP-oligo prep are available. We can deliver plate-ready or strip-ready formats with full QC.

Storage & handling tips?

Store dry at −20 °C, protect from light/moisture. Avoid prolonged aqueous storage of enzyme conjugates; prepare fresh. For AuNP probes, keep ionic strength moderate and include surfactants to reduce aggregation.

Speak to a Scientist

Tell us about your colorimetric detection project. We’ll recommend the most suitable reporter (HRP/AP, AuNP, DNAzyme, redox), spacers, capture strategy, and purification/QC.

Please avoid confidential details; we can arrange an NDA if needed.

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