Dense silica coated upconverting nanoparticles - Em. Wavelength:365 nm,particle size:35 nm

Cat. No.: D140920

GRADE & PURITY Em. Wavelength:365 nm,particle size:35 nm

Synonyms

Dense silica coated UCNs

Storage

Store at 2-8°C

Shipped In

Wet ice

Übersicht

This series of products contains dense silica coated 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.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, photodynamic therapy and photoactivation of anti-cancer drugs and biomolecules

Specifications

Synonyme

Dense silica coated UCNs

Spezifikationen & Reinheit

Em. Wavelength:365 nm,particle size:35 nm

Storage

Store at 2-8°C

Verschickt in

Wet ice

Dieses Produkt erfordert Kühlkettenversand. Grundversand und andere Economy-Optionen sind nicht verfügbar.

Application Protocols

Item‑specific tested applications and dilutions are not provided. The following are general, literature‑based procedures for handling dense silica–coated UCNPs; adapt to your application and consult the CoA/Spec Sheet for product particulars.

• Redispersion of stored nanoparticles:
  1. Bring vial to 2–8 °C, then to room temperature. Gently invert to homogenize.
  2. If aggregation is observed, sonicate in a water bath for 1–5 min; avoid probe sonicators unless necessary.
  3. Optionally add 0.01% nonionic surfactant to improve colloidal stability (validate optical impact).
• Washing/exchange of medium:
  1. Centrifuge at a force just sufficient to pellet (optimize based on size/density; literature starting point 5–15k g, 5–20 min).
  2. Decant supernatant; resuspend in desired buffer/solvent by gentle vortexing and short sonication. Repeat 2–3×.
• Silanization (amine example, general):
  1. Disperse particles in anhydrous ethanol (1–5 mg/mL). Add APTES (0.2–1 vol%) with catalytic water.
  2. React 2–4 h at RT with stirring; cure 60–80 °C for 1–2 h. Wash thoroughly with ethanol then water.
• Bioconjugation (EDC/NHS, general):
  1. Activate ligand carboxyls in MES pH 5.5–6.0 with EDC/NHS (e.g., 2–10 mM) for 15–30 min.
  2. Add to amine‑functionalized particles in PBS pH 7.4; incubate 1–2 h; quench residual NHS‑esters.
• Optical measurement (general):
  • Excite with NIR source matched to dopant; collect emission with appropriate bandpass filters. Maintain constant optical path and avoid reabsorption by diluting to low OD.

Record concentrations as mg/mL solids and verify by drying/weighing if CoA does not specify solids content.

Biological Roles

This product is an inorganic nanomaterial for research use; it is not a biological macromolecule and has no intrinsic metabolic role. The following notes describe how such materials are used in biological research (literature/general), without implying clinical use.

• Upconversion mechanism (general): sequential 4f–4f energy transfer in rare‑earth–doped cores produces visible/NIR emission under NIR excitation, reducing background autofluorescence and enabling deeper optical penetration in scattering media.
• Silica shell relevance:
  • Provides a hydrophilic, low‑autofluorescence interface compatible with aqueous buffers.
  • Facilitates attachment of biomolecules (antibodies, peptides, oligos) via silane linkers for targeted labeling in vitro.
• Colloidal behavior in biofluids:
  • Protein corona formation can alter surface charge and targeting; PEGylation or zwitterionic silanes are common strategies to reduce nonspecific adsorption (literature).
  • Ionic strength and divalent cations may promote aggregation; optimize buffer composition.
• Photobiology considerations:
  • NIR excitation can reduce photodamage compared to UV/visible illumination, but local heating at high power densities is possible; calibrate irradiance and monitor temperature.

No biological identity (target, clone, isotype) is associated with this product. Any biocompatibility, cytotoxicity, or cellular uptake data are item‑specific and are not provided here. For research use only.

Buffer Applications

These nanoparticles are not buffers and do not define pH. However, dispersion in appropriate buffers is important for stability and reproducibility. The following are practical, literature‑based considerations; item‑specific parameters are not provided.

• Compatible systems (general):
  • Low–moderate ionic strength PBS, HEPES, or Tris can maintain colloidal stability; filter (0.22 µm) to remove particulates before use.
  • Avoid very high ionic strength and multivalent cations that compress the double layer and may induce aggregation.
• pH window (silica, literature):
  • Silica shells are most stable in mildly acidic to neutral media (approx. pH 3–8). Prolonged exposure to strong base (pH > 10–11) can dissolve silica; strong acids can also increase dissolution.
• Additives:
  • 0.01–0.05% nonionic surfactant (e.g., Tween‑20) may help reduce nonspecific adsorption and aggregation; verify optical compatibility.
• Practical tips:
  • Pre‑equilibrate nanoparticles in the target buffer by stepwise dialysis or serial centrifugation/redispersion to avoid osmotic shock.
  • Measure zeta potential in the working buffer to assess stability before critical assays.

Exact dispersion medium, pH, and concentration for this item: Not specified; consult the CoA/Spec Sheet.

Green Alternatives

Sustainability considerations for dense silica–coated UCNPs focus on solvent use, processing conditions, and lifecycle of rare‑earth materials. The core composition for this item is not specified; the following are general, literature‑based recommendations.

• Material aspects:
  • Silica shells are derived from abundant precursors (e.g., TEOS) and are chemically benign at end‑of‑life relative to many organic coatings.
  • Rare‑earth mining/refining has environmental impacts; design experiments to maximize reuse and recovery of nanoparticle dispersions.
• Process/solvent choices (general):
  • Prefer water/ethanol for washing and silane coupling over toluene or chlorinated solvents when compatible with the chosen silane.
  • Use room‑temperature silanization or mild curing where possible to reduce energy consumption.
  • Implement closed‑loop solvent recovery (ethanol/IPA) and minimize single‑use plastics by switching to glassware when feasible.
• Comparative view (literature/general):
  • Silica‑coated UCNPs vs. polymer‑coated UCNPs: silica offers higher thermal/chemical stability and lower leaching; polymer coatings may be synthesized in water but can introduce organic waste and plasticizers.
  • NIR‑driven photochemistry can lower photoinitiator loadings and enable thicker samples relative to UV curing, potentially improving process safety.
• End‑of‑life:
  • Segregate nanoparticle waste for potential recovery (centrifugation/filtration) and reuse in noncritical tests.
  • Avoid drain disposal; follow institutional nanomaterial waste protocols.

Where item‑specific greener processing details are required (e.g., solvent system used for shipment), refer to the CoA/Spec Sheet.

Pharmaceutical Uses

This product is offered strictly for research use only. It is not approved for use as an active pharmaceutical ingredient, excipient, or in any clinical application.

General, literature‑based context (not item‑specific and not a claim of suitability):

• Silica‑coated UCNPs have been explored in preclinical research as optical reporters and carriers due to chemical robustness and upconversion under NIR light. Silica surfaces can be further modified (e.g., PEGylation) to adjust colloidal behavior in formulation studies.
• Any putative roles (e.g., imaging contrast, tracking labels) remain investigational and subject to rigorous safety and regulatory evaluation.

Regulatory/compendial status, GMP grade, endotoxin levels, sterility: Not specified for this item; refer to CoA/Spec Sheet if applicable.

Researchers considering formulation studies should perform de novo qualification: particle sizing (DLS/TEM), zeta potential, leachables, photostability, and thorough toxicological assessment per institutional policies. No medical or clinical claims are made for this product.

Physical Properties

Item‑specific numerical specifications are not provided. The following properties describe typical behavior of dense silica–coated UCNPs and silica shells in general; they are literature/general values and not product specifications.

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Dispersibility (literature/general):
  • Silica shell renders particles hydrophilic; well‑prepared materials typically disperse in water, alcohols (ethanol, isopropanol), and common biological buffers after brief sonication.
  • High ionic strength and divalent cations can compress the electrical double layer and promote aggregation.
• Density (literature): silica ~2.0–2.2 g/cm³; composite particle effective density depends on core composition and shell fraction.
• Thermal stability (literature): inorganic cores and silica shells are thermally robust (>300 °C as solids), but dispersions may flocculate upon heating; organic capping agents, if any, can degrade at lower temperatures.
• Optical (literature):
  • Excitation commonly in the NIR (e.g., 980 or 808 nm depending on dopants); emission bands in visible/NIR via 4f–4f transitions.
  • Silica is optically transparent across UV–NIR and minimizes additional absorption.
• Surface charge (literature): native silica surfaces are mildly negatively charged above pH ~2–3 due to silanol deprotonation; isoelectric point typically ~pH 2–3 for bare silica.
• Solubility: nanoparticles are not “soluble”; they are dispersible colloids. True solubility, BP/MP, refractive index, logP, pKa: Not applicable to the composite nanoparticles or not specified for this item.

For exact size, solids content, and dispersion medium, refer to the product’s CoA/Spec Sheet.

Quality and Grades

• Grade/purity: Not specified for this item; refer to CoA/Spec Sheet.

Interpretation and typical QC for dense silica–coated UCNPs (general guidance):

• Particle size and distribution: Transmission electron microscopy (TEM) and dynamic light scattering (DLS) are used to report core size, shell thickness, hydrodynamic diameter, and polydispersity index (PDI). A dense, uniform silica layer should appear as a low‑contrast rim in TEM.
• Optical performance: Upconversion emission spectra, excitation wavelength(s), and relative quantum yield are commonly reported. A silica shell often improves photoluminescence by suppressing surface quenching (literature).
• Surface chemistry: FT‑IR/XPS/TGA can confirm silica coverage and any functional silanes (e.g., amine/PEG). Zeta potential indicates colloidal stability at given pH/ionic strength.
• Composition: ICP‑OES/MS can quantify rare‑earth dopants; EDS/SAED can confirm lattice chemistry (literature). For this item, exact composition is not provided.
• Dispersant/vehicle and solids content: Frequently reported on CoA as wt% or mg/mL; not specified here.

What the grade means (context): Nanoparticle materials may be offered as research grade, indicating characterization appropriate for R&D rather than metrology standards. Low‑fluorescence solvents and cleanroom handling reduce background for optical applications.

Stabilizers/additives: Not specified for this item; refer to CoA/Spec Sheet. If present, stabilizers (e.g., surfactants, PEG‑silanes) influence dispersion behavior and downstream surface modification.

Reaction and Applications

This product category is intended for materials science and photonic applications. Dense silica–coated UCNPs provide robust optical performance and a versatile surface for further chemistry.

Applications (literature/general):

• Imaging and sensing (research use only): NIR‑excited luminescence (e.g., 980/808 nm excitation depending on dopants) enables background‑free readouts in scattering media; silica shells support conjugation of recognition elements for analyte‑responsive probes.
• Photonics/security: Anti‑counterfeiting inks, barcodes, time‑gated displays, and optical power‑limited readers leveraging narrow f–f emission bands.
• Photocatalysis/photochemistry: Upconverted blue/UV photons can initiate reactions (e.g., polymerizations, photoclick) under NIR pumping; silica coating provides chemical durability and dispersibility.
• Assay carriers: Silica surfaces reduce nonradiative quenching and allow silanization with amine/thiol/PEG groups for bioconjugation.

Chemistry on silica shells (general tips):

• Clean the surface via alcohol washes; dry under inert gas. Avoid strong base etching.
• Perform silanization with trialkoxysilanes (e.g., APTES, MPTMS, PEG‑silanes) in dry ethanol or toluene; control water to a catalytic amount; cure at 60–110 °C as required by the silane.
• Subsequent bioconjugation: amine‑terminated shells can be coupled to carboxyls via EDC/NHS; thiol shells allow maleimide coupling; azide/alkyne shells enable CuAAC or SPAAC.
• For optical work, minimize dye or metal absorbers on the surface that can quench upconversion; use PEGylation to reduce nonspecific adsorption.

Note: Exact core composition/dopants, excitation wavelengths, and emission maxima for this item are not specified; consult the CoA/Spec Sheet for product‑specific photophysical data.

Reaction Conditions

Typical reaction/processing conditions for silica surface chemistry on UCNPs are summarized below as general literature guidance. These are not product specifications.

• Silica shell growth (Stöber method, literature):
  • Medium: ethanol/water with ammonia catalyst.
  • Precursor: TEOS (e.g., 0.1–5 vol%).
  • Temperature: ambient (20–30 °C).
  • Time: 1–24 h depending on desired thickness.
• Post‑shell silanization (e.g., APTES, PEG‑silanes):
  • Solvent: anhydrous ethanol or IPA; small, controlled water content to hydrolyze alkoxysilane.
  • Concentration: 0.1–2 vol% silane typical; avoid excess to prevent polymerization.
  • Temperature: 20–80 °C; cure 60–110 °C as per silane datasheet.
  • Time: 1–12 h reaction; thorough washing to remove unbound silane.
• Bioconjugation (amine‑terminated surfaces):
  • EDC/NHS coupling in MES (pH ~5.5–6.0) to activate carboxyls; coupling in PBS/HEPES (pH 7.2–7.5).
  • Typical times: 30–120 min activation; 1–4 h coupling at RT.
  • Include inert protein blockers or PEG to reduce nonspecific adsorption.
• Optical use (general):
  • Excitation: NIR laser/LED matched to dopant absorption (e.g., 980 or 808 nm; literature).
  • Power density: keep as low as possible to achieve signal while minimizing local heating; calibrate with actinometry or thermal probes.

Always verify nanoparticle integrity after each step (DLS/TEM/zeta, emission spectra). Exact protocols and conditions for this item are not specified; consult the CoA/Spec Sheet and optimize empirically.

Safety and Handling

Authoritative safety information must be obtained from the product SDS. The following guidance is general to silica‑coated UCNPs and nanomaterials.

• GHS classification, signal word, pictograms, H‑statements: Not specified for this item; refer to SDS.
• Primary hazards (general):
  • Nanoparticle exposure: avoid aerosol generation; inhalation of fine particulates can cause respiratory irritation. Work in a fume hood or containment when handling dry powders or generating mists/aerosols.
  • Silica shell: amorphous silica is generally considered of low acute toxicity but can be irritating to eyes/skin. Avoid inhalation/ingestion.
  • Rare‑earth content (if present in the core; literature): typically low acute toxicity; fluoride matrices are insoluble; nonetheless avoid exposure and environmental release.
• PPE: safety glasses or goggles, lab coat, and suitable gloves (e.g., nitrile). Use respiratory protection if aerosol/dust cannot be controlled.
• Handling/disposal:
  • Keep dispersions closed to minimize evaporation and contamination; mix gently to avoid foam/aerosols.
  • Collect nanoparticle waste in labeled containers; do not pour suspensions to drain without institutional approval. Follow local regulations for inorganic nanomaterial disposal.
• Incompatibilities (general):
  • Strong bases (pH > 10–11) can etch/dissolve silica shells over time; hydrofluoric acid dissolves silica rapidly. High salt/organic solvent changes can induce aggregation.
• First aid (overview; defer to SDS):
  • Eye/skin contact: rinse with water for several minutes; remove contaminated clothing. Seek medical attention if irritation persists.
  • Inhalation: move to fresh air; seek medical advice if symptoms occur.
  • Ingestion: rinse mouth; do not induce vomiting; seek medical advice.
• Fire: inorganic cores/silica are non‑flammable; packaging or organic capping agents may burn. Use extinguishing media suitable for surrounding fire.

Solvent Selection

Dense silica shells typically render UCNPs dispersible in polar media. Exact dispersants for this product are not specified; the following guidance is general (literature/practice):

• Polarity/miscibility (general):
  • Water and aqueous buffers: Often suitable due to hydrophilic silanol surfaces; maintain moderate ionic strength to minimize aggregation.
  • Alcohols (ethanol, isopropanol): Good media for storage, washing, and silane coupling; low viscosity aids mixing and sonication.
  • Aprotic polar solvents (DMF, DMSO): Can disperse after functionalization; verify compatibility with any capping agents.
• Factors influencing choice:
  • Surface functionalization (e.g., PEG‑, amine‑, or carboxyl‑terminated silanes) dictates solvent affinity and zeta potential.
  • Avoid prolonged exposure to strong base (pH > 10–11) that can etch silica, and to highly saline solutions that compress double layers.
• Practical tips:
  • For ligand exchange or silanization, anhydrous alcohols (ethanol/IPA) are common media; control water content for reproducibility.
  • For bio‑assays, use filtered, degassed buffers (e.g., PBS, HEPES) at low–moderate ionic strength; add 0.01–0.05% nonionic surfactant (e.g., Tween‑20) if compatible to reduce nonspecific adsorption (evaluate case‑by‑case).
• Comparison (general):
  • Water: best biocompatibility; may require pH/ionic control for stability.
  • Ethanol: excellent for silane chemistry and storage; evaporates cleanly.
  • DMF/DMSO: strong solvents for coupling reactions; harder to remove; consider downstream use.

Item‑specific dispersion medium and solids content: Not specified for this item; refer to CoA/Spec Sheet.

Storage and Reconstitution

• Storage conditions (item‑specific): Store at 2–8 °C.
• Shipping (item‑specific): Shipped on wet ice.
• Appearance, vehicle/solids content: Not specified for this item; refer to CoA/Spec Sheet.

General guidance for silica‑coated UCNPs:

• Do not freeze unless explicitly indicated on the CoA/SDS; freeze–thaw cycles can promote irreversible aggregation and vial breakage.
• Keep containers tightly closed to minimize evaporation and contamination. Protect from extreme pH (strong acids/bases) that can dissolve or roughen the silica shell.
• Before use, allow the vial to equilibrate to room temperature, then mix by gentle inversion. If settling has occurred, redisperse by brief bath sonication (1–5 min) and/or mild vortexing.
• For long‑term storage, consider aliquoting to minimize headspace and repeated opening. If microbial growth is a concern in aqueous dispersions, sterile‑filter through an appropriate pore size if particle size allows, or add a compatible biocide (validate that it does not affect optical properties).
• Record the date of opening and maintain a log of sonication and buffer exchanges to track colloidal stability over time.

Shelf life, concentration, and any stabilizers or preservatives: Not specified for this item; refer to CoA/Spec Sheet.

Research use only.

Structure and Identity

Dense silica coated upconverting nanoparticles (UCNPs) are inorganic core–shell nanomaterials engineered to convert near‑infrared (NIR) photons into shorter‑wavelength emission (anti‑Stokes luminescence). A dense silica shell encapsulates the upconverting core, imparting colloidal stability and a chemically versatile surface.

• Item identifiers (this product):
  • Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
  • CAS, CID, SMILES, InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
• Structural features (general/literature description, not item‑specific):
  • Core: Typically a rare‑earth–doped fluoride lattice (e.g., NaYF4:Yb/Er or Yb/Tm) that supports sequential energy transfer upconversion under ~980 nm or ~808 nm excitation (literature).
  • Shell: Dense SiO2 (amorphous silica) grown by Stöber‑type condensation around the core, forming a conformal, diffusion‑barrier layer that reduces surface quenching and enables silane chemistry (literature).
  • Morphology: Approximately spherical nanoparticles are common; core–shell architecture with a continuous silica layer (literature). Exact size, polydispersity, and shell thickness are item‑specific and are not provided here.
  • Surface chemistry: Native silica presents silanol groups (≡Si–OH) amenable to silanization (e.g., APTES, MPTMS, PEG‑silanes). Any additional surface functionalization, ligands, or dispersants are not specified for this item.

2D/“verbal” depiction: an inorganic light‑converting core centered within a uniform, amorphous silica sphere; the outer surface bears silanol sites that can be derivatized to amine/thiol/PEG groups (literature).

Synthetic Utility

While not a small‑molecule building block, dense silica–coated UCNPs are valuable as a nanoscale platform for surface functionalization and assembly. The silica shell provides robust inorganic chemistry pathways that integrate these particles into complex materials.

Key reactive handles (on silica; literature/general):

• Silanols (≡Si–OH) enable covalent attachment of trialkoxysilanes: APTES (amines), MPTMS (thiols), GPTMS (epoxides), azide/alkyne‑silanes, PEG‑silanes.
• Post‑silanization coupling: EDC/NHS amidation (carboxyl↔amine), NHS‑ester reactions, maleimide–thiol conjugation, CuAAC/SPAAC click coupling.

Synthetic roles:

• Scaffold for multivalent display of ligands, catalysts, or dyes with controlled spacing to mitigate quenching of the UC core.
• Colloidal building blocks for photonic crystals or encoded beads (barcoding) via co‑assembly with polymers or additional silica layers.
• Heterostructures: further overcoating (e.g., titania, alumina) or deposition of plasmonic metals (Au, Ag) to tune emission via plasmon–exciton interactions (literature).

Practical considerations:

• Maintain shell integrity by avoiding strong base and HF; verify coverage after each modification (TEM, FT‑IR, TGA).
• Use anhydrous alcohols for silanization with controlled water content; purge oxygen/moisture if coupling sensitive groups.
• Quantify surface group density (e.g., fluorescamine for amines) to standardize subsequent conjugations.

Item‑specific functionalization, ligand density, or preinstalled groups are not provided; refer to CoA/Spec Sheet.

Target Specificity

Not applicable. This product is a nanomaterial and does not have antigen/epitope specificity, clone, isotype, or species reactivity. If surface functionalization with targeting ligands is desired, it must be performed by the user or specified on a product variant. No item‑specific targeting information is provided.