gold nanoparticles - 10 nm diameter,carboxylic acid functionalized,＞0.75 A520 Units/ml in citrate buffer

Cat. No.: G120407

GRADE & PURITY 10 nm diameter,carboxylic acid functionalized,＞0.75 A520 Units/ml in citrate buffer

Storage

Store at 2-8°C

Shipped In

Wet ice

Specifications

Specifications & Purity

10 nm diameter,carboxylic acid functionalized,＞0.75 A520 Units/ml in citrate buffer

Storage

Store at 2-8°C

Shipped In

Wet ice

This product requires cold chain shipping. Ground and other economy services are not available.

Application Protocols

Item-specific facts (from Product Data)

• Tested applications, recommended dilutions, and positive controls are not specified for this item; refer to CoA/Spec Sheet.

Note

• Due to the diversity of use-cases (plasmonic assays, catalysis, imaging, conjugation), protocols are highly dependent on particle size, ligand shell, and concentration. Develop application-specific procedures and qualify performance with small-scale pilots.

Biological Roles

Scope

• Gold (Au) has no known essential biological role in metabolism. Gold nanoparticles (AuNPs) are used as research tools in bioanalytical chemistry and biophysics due to their unique optical and surface properties. The following are literature/general insights and not product-specific claims.

General biological interactions (literature)

• Protein corona formation: upon exposure to biofluids, AuNPs rapidly adsorb proteins forming a corona that influences cellular interactions, stability, and biodistribution in model systems.
• Bioconjugation handles: strong Au–S interactions enable site-specific tethering of cysteine-containing peptides/proteins or thiolated oligonucleotides, creating probes for immunoassays, hybridization assays, and biosensors.
• Imaging and detection: LSPR enables label-based colorimetric readouts and dark-field/photothermal microscopy; high electron density yields strong TEM contrast for labeling studies (research use only).
• Enzymatic activity modulation: nonspecific adsorption can inhibit or alter enzyme activity; blocking agents (e.g., BSA, casein, PEG) are often used to mitigate.
• Cellular interactions: uptake and responses depend strongly on size, shape, surface charge, and ligand shell; PEGylation typically reduces nonspecific interactions in vitro.

Notes and limitations

• No medical or clinical uses are claimed for this product. Any discussion of cellular or organismal interactions is for fundamental research context only.
• Exact bio-relevant attributes for SKU G120407 (size, ligand, endotoxin) are not specified; consult CoA/Spec Sheet if planning biological assays.

Buffer Applications

Applicability

• Buffers significantly influence colloidal stability and bioconjugation outcomes for gold nanoparticles. While specific buffer compatibility for this SKU is not provided, the following reflects general laboratory practice.

Item-specific facts (from Product Data)

• Supplied buffer/composition: Not specified for this item; refer to CoA/Spec Sheet.

General guidance (literature/practice)

• Storage/handling: deionized water or very low ionic strength buffers (e.g., 1–10 mM) help maintain stability of electrostatically stabilized AuNPs.
• Conjugation by passive adsorption (proteins): adjust pH to slightly above the protein pI (often pH 7.5–9.0) using low-ionic-strength borate or carbonate buffers to maximize affinity while minimizing aggregation; titrate salt post-adsorption ("salt-aging") to screen residual charges.
• Covalent coupling on functional shells: use buffers compatible with coupling chemistry (e.g., phosphate or HEPES without primary amines for EDC/NHS on carboxyl-PEG; phosphate-buffered saline at pH ~7.0–7.4 for maleimide–thiol; avoid Tris in EDC/NHS reactions due to competing amines).
• Additives:
  • Avoid thiols (e.g., DTT, βME) unless reacting via thiol chemistry—they can strip ligands and destabilize colloids.
  • Include blocking proteins (BSA/casein) or PEG to mitigate nonspecific adsorption in assays.
• Ionic strength: divalent cations (Mg2+, Ca2+) and high NaCl can induce aggregation for citrate-capped AuNPs; introduce gradually while monitoring LSPR.

Note

• Verify buffer compatibility empirically with small-scale tests. Exact buffer recommendations for SKU G120407 are not specified; refer to the CoA/Spec Sheet.

Green Alternatives

Context

• Gold nanoparticles are often prepared in water using relatively benign reductants (e.g., citrate, ascorbate), offering greener profiles compared to organometallic/organic-phase syntheses. Nonetheless, synthesis and use can involve surfactants, quaternary ammonium salts, or organic solvents.

Greener synthesis strategies (literature)

• Aqueous citrate reduction (Turkevich method): water as solvent; citrate serves as both reductant and capping agent; avoids halogenated solvents and strong surfactants.
• Ascorbate- or glucose-mediated reductions: renewable reductants in water; good for seed-mediated growth with reduced byproduct toxicity.
• Plant extract/biogenic routes: use phytochemicals as reducing/stabilizing agents; variability can be higher—best for exploratory research rather than precision applications.
• Ligand selection: switch from CTAB/TOAB to PEG-thiols or zwitterionic ligands to reduce toxicity and improve biocompatibility.

Comparative considerations (general)

• Aqueous citrate-capped AuNPs vs. CTAB-stabilized rods:
  • Solvent: water vs. water + cationic surfactant micelles
  • Hazard: low vs. higher acute aquatic toxicity (CTAB)
  • Utility: spheres easy to conjugate; rods useful for NIR plasmonics but require surfactant exchange for greener profiles.
• Gold vs. cadmium-based quantum dots:
  • Heavy metal risk: gold (noble, low solubility) vs. cadmium chalcogenides (toxic Cd2+ risk)
  • Optical: plasmonic scattering/absorption vs. size-tunable fluorescence; selection depends on application.

Recommendations

• Prefer water-based syntheses, avoid persistent surfactants, and implement ligand exchanges to biocompatible shells when possible.
• Recover and recycle gold from waste streams (e.g., thiol resin capture, precipitation) to reduce environmental burden.

Pharmaceutical Uses

Item-specific facts (from Product Data)

• No pharmacopeial grade or formulation role is specified for this item; refer to CoA/Spec Sheet.
• Research use only; not for human or veterinary use.

General formulation/manufacturing context (literature/practice; no therapeutic claims)

• Diagnostic manufacturing: colloidal gold is widely used as the visible label in lateral flow immunoassays (LFAs), where antibody–AuNP conjugates are immobilized on conjugate pads and produce red/purple lines on nitrocellulose.
• Excipient-like roles in research devices: AuNPs can serve as optical reporters, signal amplifiers (via silver enhancement), or catalytic tags in in vitro diagnostic prototypes.
• Stabilization strategies: for biologics conjugation, PEGylation and protein coronas (e.g., BSA) are used to reduce nonspecific binding and improve shelf stability under refrigerated conditions.
• Regulatory considerations: diagnostic-grade colloidal gold often targets tight specifications on particle size distribution, residual surfactants, and bioburden/endotoxin. Trace metal impurities are less critical than for small-molecule APIs but batch optical uniformity is paramount.

Recommendations

• If considering use in assay development or prototyping, request specifications for particle size, optical density (OD at LSPR), stabilizer identity, and bioburden.
• Establish stability-indicating methods (UV–Vis LSPR tracking, DLS) to support shelf-life studies at 2–8 °C.

Notes

• No claims are made regarding compliance with pharmacopeial monographs or suitability for clinical diagnostics for this SKU without supporting documentation.

Physical Properties

Item-specific facts (from Product Data)

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Concentration, particle size, capping ligand, dispersant: Not specified for this item; refer to CoA/Spec Sheet.

Literature/general values and behavior (not item specifications)

• Optical properties: exhibit a localized surface plasmon resonance (LSPR) absorption band whose maximum depends on size/shape and medium (typical ~515–530 nm for ~10–30 nm spherical citrate-stabilized AuNPs in water; red-shifts with increasing size/aggregation).
• Density: bulk Au 19.3 g/cm3 (literature). Effective density of colloids depends on solvent and ligands.
• Melting point: bulk Au 1064 °C (literature); nanoparticles display depressed melting points that decrease with size (Gibbs–Thomson effect).
• Solubility/dispersion: metallic cores are insoluble; nanoparticles are dispersible in the continuous phase via ligand/electrostatic stabilization. Aqueous citrate-capped AuNPs are typically stable at low–moderate ionic strength; high salt can induce aggregation unless protected (e.g., by PEG).
• Zeta potential: stabilizer-dependent (e.g., citrate-capped often −20 to −50 mV in low-ionic-strength water); governs colloidal stability (literature trends).
• Refractive index sensitivity: LSPR peak position is sensitive to the refractive index of the surrounding medium (basis for sensing applications).
• Thermal/photostability: generally photostable; heating or drying can induce sintering/aggregation, altering optical/catalytic properties.

Notes

• Do not construe the above as specifications for SKU G120407. Exact numerical values (size, LSPR maximum, zeta potential, concentration, dispersant, and stabilizer identity) are not specified for this item; refer to the CoA/Spec Sheet.

Quality & Grades

Item-specific facts (from Product Data)

• Grade/purity: Not specified for this item; refer to CoA/Spec Sheet.
• Stabilizer/ligand identity, particle size distribution (PSD), polydispersity index (PDI), concentration, endotoxin/bioburden: Not specified for this item; refer to CoA/Spec Sheet.

How to interpret grades and typical quality controls (general guidance)

• Common quality attributes for gold nanoparticle reagents:
  • Particle size and PDI (e.g., by TEM/DLS); narrow PSD is critical for reproducible optical and catalytic performance.
  • Optical characterization: LSPR maximum, full width at half maximum (FWHM), A520/A650 ratio (for spheres) as an aggregation indicator.
  • Concentration: particles/mL or mass/volume; extinction coefficient-based quantification cross-checked by ICP-OES for total Au.
  • Surface chemistry: ligand identity and coverage (e.g., citrate, PEG-thiol); zeta potential for colloidal stability; residual reducing agents/impurities.
  • Purity/contaminants: residual ions (Na+, Cl−), organic residues, and microbial/endotoxin levels for bio-conjugation suitability.
• Grade implications:
  • “Bio-conjugation grade” typically indicates low salt/low additive background, controlled pH, and endotoxin/bioburden specifications suitable for protein coupling.
  • “Catalyst grade” often emphasizes minimal organic ligands, higher surface cleanliness, and batch-to-batch activity consistency.
  • “Analytical/diagnostic grade” prioritizes optical uniformity and low background for LFAs and plasmonic assays.

Recommendations

• Request the CoA/Spec Sheet for this SKU to confirm PSD, stabilizer, concentration, and any bioburden specs before critical applications.
• Validate batch performance in your assay with a small-scale pilot, particularly for conjugation or sensing workflows.

Reaction & Applications

Item-specific facts (from Product Data)

• Manufacturer applications: Not specified for this item; refer to CoA/Spec Sheet.

General applications (literature/practice)

• Plasmonics and analytics: strong LSPR enables colorimetric sensing, aggregation assays, and surface-enhanced Raman scattering (SERS) when used as substrates or as labels.
• Bioconjugation: robust Au–S chemistry (thiolated DNA, peptides, PEG) for functionalized probes; passive adsorption of proteins onto citrate-capped spheres for immunoassays (optimize pH near protein isoelectric point).
• Catalysis: AuNPs catalyze reactions such as 4-nitrophenol reduction (NaBH4/H2O), selective alcohol oxidations, alkyne hydration, and CO oxidation; activity depends on size (<5–10 nm often most active) and support/ligand environment.
• Imaging and tracking: high electron density provides strong TEM contrast; LSPR used for dark-field and photothermal microscopy (research use only).
• Materials assembly: seed-mediated growth for anisotropic nanostructures (rods, stars); layer-by-layer films, metamaterials, and photonic crystals via controlled aggregation or DNA-programmed assembly.

Practical tips (general)

• Maintain low ionic strength during storage/handling for electrostatically stabilized particles; introduce salts gradually during conjugation (salt-aging) while monitoring LSPR and hydrodynamic size.
• Validate surface coverage by shifts in LSPR, XPS/SERS signatures, or fluorescence quenching assays; remove excess ligand by gentle centrifugation or dialysis tailored to size and stability.
• For catalytic uses, consider ligand stripping or support immobilization (e.g., on TiO2, Al2O3, carbon) to enhance activity and recyclability; avoid conditions that cause sintering (high temperature/drying without support).

Reaction Conditions

Item-specific facts (from Product Data)

• No reaction testing or conditions are specified for this item; refer to CoA/Spec Sheet.

General conditions from literature (illustrative, not specifications)

• 4-Nitrophenol reduction (benchmark):
  • Medium: water at room temperature.
  • Reagents: excess NaBH4 (e.g., 0.1–10 mM) and catalytic AuNP dispersion (nM–pM particle concentrations depending on size).
  • Monitoring: decrease of 400 nm absorbance (nitrophenolate) and emergence at ~300 nm (aminophenol).
  • Kinetics: apparent pseudo-first-order with respect to nitrophenol; rate constant scales with Au surface area.
• Alcohol oxidation:
  • Solvent: water, toluene, or alcohol solvents; base (e.g., K2CO3) and O2/air as oxidant; 25–80 °C depending on substrate and support.
  • Supported AuNPs on TiO2, CeO2, or carbon often show enhanced activity and selectivity.
• Bioconjugation (passive adsorption):
  • Buffer: low-ionic-strength borate or carbonate, pH 7.5–9.0.
  • Protein: titrate mass ratio to determine minimal stabilizing amount; salt-age gradually while monitoring LSPR/DLS.
• Covalent coupling on PEGylated shells:
  • Maleimide–thiol: pH 6.5–7.5, degassed buffers, 1–2 h at room temperature.
  • EDC/NHS (carboxyl to amine): pH 5.0–6.0 for activation (MES), pH 7.0–8.0 for coupling (phosphate/HEPES). Avoid primary amine buffers during activation.

Notes

• Parameters depend strongly on particle size, ligand, and support. These are literature norms only. Suitability of SKU G120407 for any reaction or conjugation chemistry is not specified; verify with the CoA/Spec Sheet and pilot trials.

Safety & Handling

Item-specific facts (from Product Data)

• GHS classification, signal word, pictograms, H-statements: Not specified for this item; refer to SDS.
• Storage: Store at 2–8 °C. Shipped on wet ice.
• Research use: For research use only.

General safety guidance (literature/best practice; defer to SDS for authoritative information)

• Nanomaterial precautions: handle in a well-ventilated area or fume hood; avoid aerosol generation, inhalation, and skin/eye contact. Use low-shedding wipes and minimize dry residues to prevent airborne particles.
• PPE: safety glasses, lab coat, and appropriate chemically resistant gloves. For procedures with aerosol risk, consider a respirator per institutional policy.
• Incompatibilities: avoid contact with strong oxidizers and with thiol-containing reagents unless intentional (thiols can displace surface ligands and destabilize colloids). High ionic strength and extreme pH can induce aggregation for electrostatically stabilized particles.
• Spill/cleanup: contain with inert absorbents; prevent entry into drains. Collect as nanowaste following institutional guidelines.
• First aid (overview):
  • Inhalation: move to fresh air; seek medical attention if symptoms persist.
  • Skin/eye contact: rinse with water for ≥15 min; remove contaminated clothing; seek medical advice if irritation persists.
  • Ingestion: rinse mouth; do not induce vomiting; seek medical attention.
• Waste disposal: manage as hazardous nanomaterial waste; consult local regulations and SDS.

Notes

• Without item-specific hazard classification, treat as a potentially hazardous engineered nanomaterial and implement prudent containment and hygiene practices.

Solvent Selection

Applicability

• Gold nanoparticles are supplied as colloidal dispersions. Solvent choice primarily concerns the continuous phase and any buffer excipients affecting stability and surface chemistry.

Item-specific facts (from Product Data)

• Supplied medium/composition: Not specified for this item; refer to CoA/Spec Sheet.

General guidance (literature/practice)

• Aqueous systems: citrate- or other electrostatically stabilized AuNPs are typically most stable in deionized water or low-ionic-strength buffers (≤1–10 mM). High salt or divalent cations can compress the double layer and induce aggregation.
• Organic/water-miscible cosolvents: up to modest percentages of ethanol, methanol, or glycerol can be tolerated depending on ligand; verify compatibility. PEGylated or thiol–PEG capped particles show improved tolerance to salts and solvents.
• Nonpolar media: require hydrophobic ligand shells (e.g., alkanethiols, TOAB/oleylamine); aqueous citrate-capped particles are not directly compatible without ligand exchange.
• pH considerations: electrostatically stabilized particles commonly show best stability between pH ~6–9; extremes can protonate/deprotonate ligands and destabilize.
• Additives to avoid unless intended: thiols and disulfides (can displace ligands), strong surfactants or polyelectrolytes (can bridge-flocculate), and high concentrations of proteins without proper blocking (nonspecific adsorption and aggregation).

Quick comparison (general)

• Citrate-capped (water, low salt): simple handling, easy passive adsorption to proteins; more salt-sensitive.
• PEG-thiol capped (broader media): higher colloidal stability across salts/pH; reduced nonspecific binding; conjugation requires specific chemistries (e.g., maleimide/thiol, NHS/amine on terminal groups).

Storage & Reconstitution

Item-specific facts (from Product Data)

• Storage: Store at 2–8 °C.
• Shipping: Shipped on wet ice.
• Appearance, concentration, dispersant, and stabilizer: Not specified for this item; refer to CoA/Spec Sheet.
• Research use only.

General best practices (literature/practice; not item specifications)

• Do not freeze colloidal dispersions unless explicitly validated—freeze–thaw can induce irreversible aggregation.
• Mix gently before use by slow inversion or brief, low-speed vortex with caution; avoid foaming and shear. If settling is observed, resuspend with gentle agitation; avoid sonication unless known to be compatible with the ligand shell.
• Store in tightly sealed, chemically clean containers (glass recommended for citrate-capped particles) to minimize contamination and evaporation. Avoid contact with rubber stoppers that can leach additives.
• Maintain low ionic strength and neutral pH during storage for electrostatically stabilized particles. For extended storage, consider adding compatible stabilizers (e.g., PEG or low % glycerol) after confirming compatibility.
• Track stability by periodic UV–Vis (LSPR position/shape) and DLS to detect early aggregation.
• For aliquoting, use low-protein-binding plastics or silanized glassware to limit adsorption losses; pre-wet with dispersant.

Notes

• Exact shelf life, freeze–thaw tolerance, and reconstitution instructions for SKU G120407 are not specified; refer to the CoA/Spec Sheet and SDS for definitive guidance.

Structure & Identity

Item-specific facts (from Product Data)

• Product: gold nanoparticles (SKU: G120407)
• CAS: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
• SMILES: Not specified for this item; refer to CoA/Spec Sheet.
• InChIKey: Not specified for this item; refer to CoA/Spec Sheet.

General description (literature/general knowledge)

• Composition: metallic gold cores in the zero-oxidation state, Au(0), formulated as a colloidal dispersion (typically aqueous) stabilized by surface ligands (e.g., citrate, thiols, polymers). Actual stabilizer for this item is not specified.
• Structural features: quasi-spherical or anisotropic nanocrystals composed of close-packed fcc gold lattice; high surface-to-volume ratio with facet-dependent surface atoms ({111}, {100}).
• Surface chemistry: strong affinity for soft Lewis bases—particularly thiols (R–SH) and disulfides—which form robust Au–S bonds; amines and phosphines also bind, typically more weakly than thiols. Electrostatic stabilization (e.g., citrate-capped) is common in water.
• 2D depiction in words: a central metallic core (tens of atoms to millions, depending on size) decorated by a corona of adsorbed/chemisorbed ligands; hydrodynamic diameter exceeds core diameter due to ligand shell and solvation layer.
• Terminology: “gold nanoparticles (AuNPs)” encompasses size regimes from sub-2 nm clusters (molecular-like) to >100 nm colloids; optical, catalytic, and interfacial properties are size-, shape-, and ligand-dependent.

Notes

• Exact particle size, polydispersity, ligand identity, and concentration are not specified for this item; consult the CoA/Spec Sheet for definitive identity attributes.

Synthetic Utility

Scope

• As preformed nanocatalysts and functional scaffolds, gold nanoparticles provide unique reactivity via high surface area and plasmonic excitation. The details below are literature/general guidance and not item specifications.

Catalytic utility (general)

• Reductions: benchmark reduction of 4-nitrophenol to 4-aminophenol with NaBH4 in water; reaction rate scales with available surface sites and particle dispersion. Useful for catalyst screening and kinetic studies.
• Oxidations: selective aerobic oxidation of alcohols and polyols (often with base) in water or alcohols; activity enhanced for sub-5–10 nm particles, commonly on oxide or carbon supports.
• Alkyne hydration and C–C/C–N couplings: gold nanoparticles (often supported, sometimes with cooperative bases) catalyze Markovnikov hydration, A3 coupling (aldehyde–amine–alkyne), and other transformations under mild conditions.
• Plasmon-assisted chemistry: under resonant illumination, hot carriers and local heating can accelerate reactions on AuNP surfaces.

Nanoconstruction/functionalization

• Seed-mediated growth: AuNPs serve as seeds for rods, bipyramids, stars using surfactant-directed anisotropic growth (CTAB/CTAC with Ag+ co-additives); post-synthesis ligand exchange enables application-tailored surfaces.
• Surface conjugation: Au–S bonding to thiolated ligands/DNA/PEG; EDC/NHS chemistry on carboxyl-terminated shells; click chemistry on azide/alkyne-modified coronas for modular assembly.

Practical considerations

• Ligand effects: strongly bound organic shells can impede catalytic access; partial ligand removal or support immobilization can enhance performance.
• Stability: avoid drying unsupported particles prior to catalysis to limit sintering; maintain dispersion and moderate temperatures.

Note

• For this SKU, catalyst grade, ligand identity, and support are not specified; confirm suitability for the intended transformation with the CoA/Spec Sheet.

Target Specificity

Not applicable

• This product is a nanomaterial reagent, not a biological affinity reagent (e.g., antibody, aptamer). No target, clone, isotype, or species reactivity applies.
• Item-specific binding specificity data are not provided; refer to CoA/Spec Sheet if conjugated or functionalized variants are offered.

Frequently Asked Questions

How should this product be stored?

Store at 2–8 °C. Refrigerated storage is required to maintain the specified shelf life.

How is this product shipped?

This product ships chilled on wet ice. Unpack on arrival and transfer it to the storage condition stated above.