Carboxyl-functionalized upconverting nanoparticles - Em. Wavelength:365 nm,particle size:35nm,Coating:PEG-COOH

Cat. No.: C140940

GRADE & PURITY Em. Wavelength:365 nm,particle size:35nm,Coating:PEG-COOH

Synonyms

Functionalized UCNs

Storage

Room temperature

Shipped In

Normal

Overview

This series of products contains amino functionalized NaYREF4 (RE:Yb, Er, Tm, Gd, Mn, Lu) UCNs with optimal excitation wavelength at 975 nm. The sensitizer is Yb3+, and the activator is Er3+ or Tm3+. The doping concentrations are optimized, leading to strong upconverted emissions at specific wavelengths.The nanoparticles are highly hydrophilic due to the silica coating or PEG coating. The UCNs are of high quantum efficiency and very photostable
After proper surface modification and functionalization, the products can be used for fluorescence imaging, biodetection, immunity analysis and photoactivation of anti-cancer drugs and biomolecules.

Specifications

Synonyms

Functionalized UCNs

Specifications & Purity

Em. Wavelength:365 nm,particle size:35nm,Coating:PEG-COOH

Storage

Room temperature

Shipped In

Normal

Application Protocols

The following general protocols illustrate common workflows with carboxyl-functionalized UCNPs. Item-specific parameters (particle size, concentration, ligand identity) are not provided; optimize empirically.

• Basic dispersion (aqueous):

  1. Add the desired mass/volume of UCNPs to ultrapure water or 10 mM HEPES, pH 7.4. 2) Sonicate in a bath sonicator for 5–10 min, avoiding overheating. 3) Optional: Pass through a 0.45 or 0.22 µm filter if particle size permits.

• EDC/NHS bioconjugation:

  1. Exchange UCNPs into 50 mM MES, pH 5.5. 2) Add EDC (e.g., 5 mM) and NHS (e.g., 10 mM); incubate 15 min at RT. 3) Quickly transfer to 50 mM phosphate, pH 7.4 containing the amine-bearing biomolecule (molar excess). 4) Incubate 1–2 h at RT with gentle mixing. 5) Quench with 20 mM ethanolamine or Tris for 15 min. 6) Purify by centrifugation (e.g., 10–20k g, time dependent on particle size) or diafiltration. 7) Characterize by DLS, zeta, and emission.

• Preparing inks/coatings:

  1. Disperse UCNPs in ethanol/water (80:20) with 0.01–0.05% w/v polymer binder. 2) Sonicate; adjust viscosity as needed. 3) Apply by spin/inkjet/spray. 4) Dry at ambient or mild heat; avoid conditions that degrade the ligand shell.

• Fluorescence readout:

  • Excite with NIR diode (e.g., ~980 nm; actual optimum depends on dopants, not specified). Use appropriate emission filters. Keep power densities modest to prevent local heating; report excitation conditions for reproducibility.

• Troubleshooting:

  • Aggregation: Increase pH to 7.5–8.0, lower ionic strength, add small amounts of nonionic surfactant (e.g., 0.01% Tween-20) if compatible, or perform brief probe sonication.

Biological Roles

This product is an engineered inorganic nanomaterial and has no inherent biological role or metabolic function. The following points provide context for research utility only (no clinical/medical claims):

• Interaction with biological systems (general literature):

  • Carboxylated surfaces confer negative charge at physiological pH, influencing protein corona formation, cellular uptake pathways, and colloidal stability in biofluids.
  • Amide coupling via EDC/NHS allows covalent attachment of biomolecules (antibodies, peptides, nucleic acids) to create targeted probes and biosensors for in vitro and ex vivo studies.
  • Upconversion under NIR excitation enables low-autofluorescence readouts in thick or scattering samples compared to UV/visible excitation.

• Biocompatibility considerations (general):

  • Core material (rare-earth fluorides) is generally considered less acutely toxic than heavy-metal chalcogenide QDs; nonetheless, nanoparticle size, surface chemistry, and dose critically determine cellular responses.
  • Surface coatings (PEG, proteins, polysaccharides) can attenuate nonspecific interactions and modulate biodistribution in model systems; such coatings are not specified for this item.

• Enzymatic/biochemical reactivity:

  • UCNPs are not substrates or inhibitors of natural enzymes by design; any interactions are typically nonspecific adsorption or energy-transfer–based readouts engineered into the assay.

• Guidance:

  • Validate colloidal stability and bioconjugation efficiency in the intended biological matrix (e.g., serum-containing buffers) before use. Follow institutional biosafety and nanomaterial handling policies.

Buffer Applications

While not a classical buffer reagent, the performance of carboxyl-functionalized UCNPs depends strongly on buffer composition and pH. The –COOH/–COO− equilibrium controls dispersion and coupling chemistry.

• Dispersion and storage (general guidance):

  • Use low-ionic-strength buffers (e.g., 1–10 mM HEPES or phosphate, pH 7.2–7.8) to maintain electrostatic stabilization. High salt (>100–150 mM) can screen charges and promote aggregation.
  • Avoid multivalent cations (Ca2+, Mg2+, Fe3+) unless specifically required; they can bridge carboxylates and cause flocculation.

• EDC/NHS coupling workflow (general literature):

  • Activation buffer: MES, 25–100 mM, pH 5.0–6.0 (amine-free) to form O-acylisourea/NHS-esters on the particle surface.
  • Coupling buffer: Phosphate or HEPES, 10–50 mM, pH 7.2–7.5 containing the amine-bearing ligand/biomolecule. Avoid primary-amine buffers (e.g., Tris, glycine) during activation to prevent side reactions.
  • Quench: Ethanolamine or Tris after coupling to cap residual active esters (introduces amines; use only post-coupling).

• Filtration and cleaning:

  • Employ centrifugal filtration (e.g., 50–300 kDa MWCO, depending on particle size/ligand) or gentle centrifugation–resuspension cycles to exchange buffers and remove excess reagents.

• pH/charge control:

  • Monitor zeta potential across pH 4–9 to map the isoelectric region for the specific lot. Item-specific IEP is not provided; consult CoA/Spec Sheet if available.

Green Alternatives

Considering environmental and safety aspects for photonic nanomaterials:

• Material choice (general literature perspective):

  • UCNPs based on rare-earth fluorides (e.g., NaREF4) avoid cadmium/lead present in many conventional quantum dots, reducing concerns about toxic heavy metals. However, mining/refining of rare-earths has its own environmental footprint.

• Process and solvent recommendations (general):

  • Prefer aqueous or ethanol-based processing for carboxylated UCNPs to minimize use of high-boiling polar aprotic solvents (DMF/DMSO) that complicate waste streams.
  • Employ buffer systems compatible with carbodiimide chemistry (MES, phosphate) and avoid excess organic additives.
  • Use low-power NIR excitation sources with good optical coupling to reduce energy consumption during assays.

• End-of-life and waste handling:

  • Collect nanoparticle-containing wastes separately; avoid discharge to drains. Implement flocculation and filtration to concentrate slurries prior to disposal per local regulations.

• Comparison table (general):

  Greener alternative | Typical trade-off

  • Aqueous ligand exchange to –COOH shells vs. high-temperature organic syntheses | Potentially broader size distribution; may reduce absolute quantum yield without core–shell engineering
  • Rare-earth UCNPs vs. Cd/Pb quantum dots | Lower heavy-metal toxicity concerns; UCNPs often have lower brightness per particle at equal excitation power
  • Ethanol/water processing vs. DMF/DMSO | Improved EHS profile; possible aggregation if ionic strength/pH not controlled

Note: Item-specific synthesis route, dopant system, and associated EHS metrics are not specified; consult CoA/SDS for details.

Pharmaceutical Uses

This material is supplied strictly for research use only and is not approved for diagnostic, therapeutic, or clinical applications.

• Formulation context (general, non-clinical):

  • Carboxyl-functionalized UCNPs can serve as luminescent markers in pre-formulation and analytical development studies (e.g., tracking dispersion stability, imaging excipient matrices) under research conditions.
  • –COOH groups enable conjugation to polymers (e.g., PEG, PLGA, chitosan derivatives) to create research-grade composite materials for in vitro release testing and device prototyping.

• Pharmacopeial status:

  • No pharmacopeial monograph is associated with upconverting nanoparticles; item-specific regulatory status is not provided.

• Manufacturing R&D utilities (general):

  • Optical tracers for process visualization (mixing studies, coating uniformity) using NIR excitation to minimize interference from ambient light.
  • Stability markers in accelerated testing of research matrices (monitoring emission as a proxy for aggregation or matrix interactions).

• Notes and limitations:

  • Particle size, composition, surface chemistry, and residual synthesis reagents critically impact biocompatibility and regulatory classification; none of these specifications are provided for this item and must not be inferred.
  • Any use in human or animal administration is outside the scope of supply. Adhere to institutional and regulatory guidelines for nanomaterial handling and disposal.

Physical Properties

Item-specific physical constants are not provided in the Product Data; consult the CoA/Spec Sheet for measured values.

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Bulk composition metrics: Molecular weight and formula are not meaningful for polydisperse nanoparticle ensembles; Not specified for this item; refer to CoA/Spec Sheet.
• Dispersibility (general literature context):
  • Carboxyl-functionalized UCNPs typically disperse in polar protic solvents (water, alcohols) when deprotonated; aggregation increases at low ionic strength and near the isoelectric point (literature).
  • Zeta potential is usually negative at pH > 6 due to –COO− groups; magnitude depends on ligand density and ionic strength (literature).
• Optical properties (general literature values):
  • Upconversion excitation bands often lie near 975–980 nm (Yb3+ sensitization) with emissions in green (~540–560 nm), red (~650–670 nm), and/or blue (~450–490 nm) depending on dopant (literature). Actual excitation/emission maxima, full width at half maximum (FWHM), and quantum yield are not specified for this item.
• Thermal/chemical robustness (literature):
  • Inorganic UCNP cores are thermally stable well above room temperature; surface ligands may desorb or reorganize upon heating or in high-ionic-strength media.
• Particle size and polydispersity: Not specified for this item; refer to CoA/Spec Sheet.
• Density and refractive index: Not specified for this item; refer to CoA/Spec Sheet.

Quality & Grades

• Grade/Purity (item-specific): Not specified for this item; refer to CoA/Spec Sheet.

• What to expect in UCNP quality documentation (general best practices):

  • Particle size and polydispersity: Transmission electron microscopy (TEM) mean diameter and distribution; dynamic light scattering (DLS) hydrodynamic diameter in specified media.
  • Crystal phase: Powder X-ray diffraction (XRD) indicating cubic vs hexagonal phase. Hexagonal (β) phases often show higher upconversion efficiency (literature).
  • Composition and dopant levels: Inductively coupled plasma (ICP) analysis for rare-earth content and dopant mol% (e.g., Yb3+, Er3+/Tm3+/Ho3+). Not specified for this item.
  • Surface chemistry: Verification of –COOH functionality via FTIR (ν(C=O) ~1700 cm−1; ν(C–O) ~1200–1300 cm−1), TGA for ligand loading, and titration/zeta potential vs pH. Not specified for this item.
  • Optical characterization: Upconversion emission spectra under defined NIR excitation power density; relative quantum yield or brightness benchmarking (literature). Not specified for this item.

• Implications of carboxyl functionalization (general):

  • Facilitates aqueous dispersion at neutral-basic pH and enables carbodiimide (EDC/NHS) coupling to amines on biomolecules, polymers, and surfaces.
  • Stability in buffers depends on ionic strength and multivalent ions; specifications typically include recommended storage/dispersing media.

• Documentation: For item-specific acceptance criteria (size, emission maxima, phase, ligand identity/loading), please refer to the CoA/Spec Sheet provided with the lot.

Reaction & Applications

Carboxyl-functionalized upconverting nanoparticles (UCNPs) are versatile photonic nanomaterials used in labeling, sensing, and light-conversion tasks. They are not typical stoichiometric reagents, but their surface –COOH groups enable robust coupling chemistries.

• Photonic applications (general literature):

  • NIR-to-visible upconversion under ~975–980 nm excitation for background-free luminescent labeling, anti-Stokes thermometry, security inks, and spectral converters. Emission bands depend on dopants (not specified for this item).
  • Photostability and minimal photobleaching enable long-term imaging in materials and life-science experiments (research use only).

• Surface-coupling reactions (general):

  • Carbodiimide coupling (EDC/NHS): Activate –COOH to O-acylisourea/NHS-esters; couple to primary amines on proteins, peptides, polymers, or surfaces to form stable amide bonds.
  • Click-compatible workflows: Introduce azides/alkynes via amide coupling, then perform CuAAC or SPAAC with complementary partners.
  • Layer-by-layer assembly: Electrostatic adsorption of polycations (e.g., PEI, PAH) onto –COO− surfaces for multilayer coatings and charge inversion.

• Sensor and assay construction (general):

  • Energy transfer platforms (UCNP–acceptor FRET-like systems) exploiting upconversion emission overlap with dye/probe absorptions.
  • Ratiometric probes by co-doping (not specified here) and by spectral filtering, for temperature or analyte sensing in materials.

• Practical tips:

  • Maintain pH control during EDC/NHS steps (activation ~pH 5–6; coupling ~pH 7–8). Remove excess reagents by centrifugal washing or size-exclusion.
  • Validate dispersion by DLS and zeta potential before and after bioconjugation; monitor emission intensity under fixed excitation to assess ligand/shell integrity.

Reaction Conditions

Representative conditions for common transformations involving carboxyl-functionalized UCNP surfaces (general literature guidance; adjust empirically to your system). Item-specific parameters are not provided.

• EDC/NHS amide coupling:

  • Activation: Disperse particles in 25–100 mM MES buffer, pH 5.2–6.0. Add EDC (e.g., 2–10 mM final) and NHS (5–25 mM) while gently stirring. Incubate 10–30 min at room temperature.
  • Coupling: Rapidly exchange to amine-containing buffer (phosphate or HEPES, pH 7.2–7.6). Add amine partner at molar excess relative to estimated surface –COOH sites. React 1–4 h at room temperature. Protect from microbial contamination; light protection is optional (UCNPs are photostable).
  • Quench: Add ethanolamine or Tris (10–50 mM) to cap residual actives. Wash by centrifugation or diafiltration.

• Electrostatic layer-by-layer (LbL):

  • Alternate adsorption of polycation (e.g., PAH, PEI; 0.1–1 mg/mL in 10 mM NaCl) and polyanion (e.g., PSS) with intermediate washes. Monitor zeta potential reversal each step.

• Solvent exchange:

  • Gradual mixing with target solvent (e.g., water→ethanol) under sonication; maintain pH > 7 to keep –COOH deprotonated. Assess by DLS before/after.

• Conjugation outcome assessment:

  • DLS (hydrodynamic diameter), zeta potential, UV–vis (for bound chromophores), and steady-state upconversion spectra under defined NIR excitation. Typical reaction times/yields vary with ligand density and partner; quantitative “yield” is best reported as coupling density (e.g., nmol ligand per mg NP), which is system-specific.

Safety & Handling

Hazard classification for this specific item is not provided in the Product Data. Always consult the product SDS for authoritative safety information.

• GHS information (item-specific):

  • Signal Word: Not specified for this item; refer to SDS.
  • H-Statements: Not specified for this item; refer to SDS.
  • GHS Classification/Pictograms: Not specified for this item; refer to SDS.

• General nanoparticle safety (literature/guidance):

  • Avoid inhalation of nanoparticulate dusts/aerosols; handle powders in a certified fume hood or enclosure. Use respirators as per institutional policy when aerosolization risk exists.
  • Prevent skin/eye contact. Recommended PPE: lab coat, safety glasses or goggles, and appropriate gloves (e.g., nitrile). Wash thoroughly after handling.
  • Minimize generation of airborne particles; use wet methods for cleanup. Do not pipette by mouth. Keep containers tightly closed.

• Incompatibilities/precautions (general):

  • Strong acids/bases and high-ionic-strength buffers can destabilize surface ligands and induce aggregation. Multivalent cations (e.g., Ca2+, Fe3+) may bridge –COO− groups and flocculate dispersions.
  • Organic solvents may strip weakly bound carboxylate ligands; evaluate stability before solvent exchange.

• First-aid overview (general):

  • Inhalation: Move to fresh air; seek medical attention if symptoms persist.
  • Skin/eye contact: Rinse with water for ≥15 min; remove contaminated clothing; obtain medical advice.
  • Ingestion: Rinse mouth; do not induce vomiting; seek medical attention.

• Environmental: Prevent release to the environment; collect nanoparticle-containing wastes for appropriate disposal per local regulations.

Solvent Selection

This product is intended for use as a nanoparticle dispersion or conjugation substrate rather than as a bulk solvent. Solvent choice affects colloidal stability and surface reactivity.

• Polarity/miscibility considerations (general literature guidance):

  • Carboxyl-functionalized UCNPs are typically hydrophilic when deprotonated; they disperse in water and some polar protic solvents (e.g., ethanol) with sonication.
  • Near the isoelectric point or in low-dielectric media, electrostatic stabilization diminishes and aggregation may occur. Buffering at pH 7–8 and moderate ionic strength (≤50–100 mM monovalent salts) often maintains stability.

• Suggested media by use case (general):

  • Stock dispersion: Ultrapure water (pH ~7–8, adjusted with dilute NaOH if needed) or low-ionic-strength PBS. Filter (0.22 µm) solvents to minimize nucleation of aggregates.
  • Conjugation (EDC/NHS): Use carboxyl activation buffers that lack primary amines and have controlled pH, such as MES (pH 5.0–6.0) for activation and phosphate/HEPES (pH 7.2–7.5) for coupling. Avoid Tris during activation.
  • Organic processing: If ligand shell permits, short-chain alcohols (EtOH) can be used; strong solvents (DMF, DMSO) may disrupt ligand shells—evaluate by DLS/ZP.

• Comparison (general):

  • –COOH UCNPs vs amine-terminated UCNPs: Carboxyl surfaces provide negative charge and EDC/NHS compatibility; amine surfaces are cationic and couple via NHS-esters or glutaraldehyde.
  • –COOH UCNPs vs hydrophobic (oleate) UCNPs: Aqueous handling is straightforward for –COOH particles; hydrophobic particles require nonpolar solvents or ligand exchange.

Storage & Reconstitution

• Storage conditions (item-specific from Product Data):

  • Store at room temperature.
  • Shipped: Normal conditions.

• General storage guidance (nanoparticles; consult CoA for lot-specific instructions):

  • Keep container tightly closed to prevent contamination and evaporation of dispersants (if supplied as a dispersion). If supplied as a dry powder, store in a clean, dry environment; desiccation can help prevent moisture-mediated aggregation.
  • Protect from extreme temperatures and repeated freeze–thaw cycles. While UCNP cores are photostable, avoid unnecessary prolonged exposure to high-intensity light to maintain consistent measurement baselines.
  • If sterility is required for biological assays, filter-sterilize compatible dispersions (e.g., 0.22 µm, size permitting) or prepare under aseptic conditions.

• Reconstitution (general):

  • To reconstitute dry material, add an appropriate volume of ultrapure water or low-ionic-strength buffer (e.g., 10 mM HEPES, pH 7.4). Sonicate in a bath for 5–10 min to disperse. Adjust pH to 7.4–8.0 to deprotonate –COOH groups for improved stability.
  • For conjugation workflows, exchange into MES buffer (pH 5–6) before EDC/NHS activation, then into phosphate/HEPES (pH 7–8) for coupling.

• Shelf life:

  • Not specified for this item; refer to CoA/Spec Sheet. Monitor dispersion by DLS/zeta and emission intensity over time to assess stability.

• Notes:

  • Do not allow dispersions to dry on container walls; this can lead to irreversible aggregation. Use low-binding plastics or glassware and gentle mixing to maintain homogeneity.

Structure & Identity

This product consists of inorganic upconverting nanocrystals bearing surface-exposed carboxyl (-COOH/-COO−) groups for downstream conjugation and dispersion control.

• Item-specific identifiers:

  • 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 applicable to inorganic nanocrystal composites; Not specified for this item; refer to CoA/Spec Sheet.
  • InChIKey: Not applicable to inorganic nanocrystal composites; Not specified for this item; refer to CoA/Spec Sheet.

• Structural description (general literature context):

  • Core: Upconverting nanoparticles (UCNPs) are typically lanthanide-doped inorganic crystals (e.g., NaREF4 lattices) that absorb near-infrared (NIR) photons and emit at shorter wavelengths via multiphoton upconversion (literature).
  • Dopants: Common activator/sensitizer pairs include Er3+/Yb3+, Tm3+/Yb3+, or Ho3+/Yb3+ (literature). Specific dopant stoichiometry for this item is not specified.
  • Surface chemistry: The particles are functionalized with terminal carboxyl groups. At neutral-to-basic pH these groups are deprotonated (–COO−), imparting negative surface charge and enabling carbodiimide coupling to primary amines. The –COOH moieties may be presented by small ligands (e.g., citrates) or polymeric shells (e.g., poly(acrylic acid)); exact ligand identity is not specified for this item.
  • Morphology: UCNPs are commonly quasi-spherical or hexagonal prisms on the 5–100 nm scale (literature). Actual size/shape distribution for this item is not specified; consult CoA/Spec Sheet.

• Category: Materials science; upconverting nanomaterials with carboxyl surface functionality for bioconjugation and materials integration.

Synthetic Utility

Although not a molecular reagent, carboxyl-functionalized UCNPs are valuable building blocks for constructing hybrid materials, optical devices, and functional conjugates.

• Functional handles (general):

  • –COOH/–COO− moieties on the surface support amide-bond formation (EDC/NHS), hydrazide coupling (after conversion to acyl azides/NHS-esters), and thiol-maleimide workflows after appropriate linker installation.
  • Electrostatic assembly with polyelectrolytes enables layer-by-layer films and capsules incorporating UCNPs.

• Materials integration (general examples):

  • Embedding into polymer matrices (epoxy, PMMA, sol–gel silicas) to create NIR-excited phosphors and anti-counterfeiting inks.
  • Surface grafting onto silica shells or metal–organic frameworks by first coupling silane- or carboxyl-reactive linkers.
  • Patterning via inkjet or microcontact printing of aqueous UCNP dispersions for photonic microarrays.

• Retrosynthetic perspective:

  • Treat the nanoparticle as a multifunctional scaffold bearing numerous carboxyl sites with an effective valency set by ligand density. Control of coupling stoichiometry is achieved by limiting active-ester equivalents and using excess amine partner.

• Practical considerations:

  • Characterize post-functionalization by FTIR (amide I/II), TGA (ligand loading changes), DLS/zeta (size/charge shifts), and steady-state emission under defined NIR power.
  • Prevent crosslinking/gelation during coupling by working at low particle concentrations and using monofunctional linkers when needed.

Item-specific ligand identity/loading and UCNP core composition are not specified; consult CoA/Spec Sheet for details.

Target Specificity

Not applicable. This product is a functional nanomaterial, not a biological affinity reagent (e.g., antibody/aptamer). No target antigen, epitope, clone, isotype, or species reactivity is defined for this item. For targeted applications, users may conjugate appropriate recognition elements (antibodies, peptides, oligonucleotides) to the surface carboxyl groups using standard coupling chemistries.