pH Ranges for Qdot® Nanocrystals

pH Recommendations
>9 Not recommmended- Qdot® nanocrystals start to self-aggregate/clump.
(Qdot® nanocrystals are not degraded by basic pH. )
>6 to <9 Qdot® nanocrystals most optimal stability in this pH range.
>5 to <6 Marginal stability is shown in this range
<4 Not recommended- The polymer will dissociate; exposed core/shell will start to dissociate.

Storage Suggestions

Aqueous soluble Qdot nanocrystals are stored and shipped in Borate Buffer pH 8.3 between 1-8 µM concentrations.

Organic soluble Qdot Nanocrystals are stored and shipped in decane in a 1 µM concentration.

Filter Sets (optimum and usable)

  Omega Optical Filter Sets Chroma Technology Filter Sets
Color Optimal Filter Sets Useable Filter Sets* Optimal Filter Sets Useable Filter Sets*
800† F307 Qdot® 800 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 800WB80 XF308 Qdot® 800 filter set for multiplexing Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 840WB80 Qdot® 800 filter set (30 nm EM; 32020) (460SPUV / 475DCXRU / D800 / 30nm) Qdot® 800 filter set (50 nm EM; 32021) (460SPUV / 475DCXRU / D800 / 50nm) Cy7 (41009) Li-Cor for IRDye 800 (41037) Cy7 (SP106)
705† XF306 Qdot® 705 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 710AF40 XF140-2 XF70 XF110-2 XF141-2 XF48-2 Qdot® 705 filter set (20 nm EM; 32014) (460SPUV / 475DCXRU / D705 / 20nm) Qdot® 705 filter set (40 nm EM; 32015) (460SPUV / 475DCXRU / D705 / 40nm) Cy5 longpass (41024) Cy5 (41008) Cy5 narrow excitation (41033) Cy5.5 (41023) Alexa Fluor® 680 (41042) Cy5.5 (red-shifted; 41022)
655 XF305 Qdot® 655 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 655WB20 XF102-2 XF40-2 XF42 XF45 Qdot® 655 filter set (20 nm EM; 32011) (460SPUV / 475DCXRU / D655 / 20nm) Qdot® 655 filter set (40 nm EM; 32012) (460SPUV / 475DCXRU / D655 / 40nm) Qdot® 655 filter set (20 nm EM; 32011) (460SPUV / 475DCXRU / D655 / 20nm) Qdot® 655 filter set (40 nm EM; 32012) (460SPUV / 475DCXRU / D655 / 40nm)
605 XF304 Qdot® 605 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 605WB20 XF108-2 XF102-2 XF103-2 Qdot® 605 filter set (20 nm EM; 32003) (460SPUV / 475DCXRU / D605 / 20nm) Qdot® 605 filter set (40 nm EM; 32007) (460SPUV / 475DCXRU / D605 / 40nm) Cy3 narrow excitation (41007a) Texas Red®/Cy3.5 (31004) TRITC (41002, 41002a, 41002b) Ethidium bromide (41006)
585 XF303 Qdot® 585 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 585WB20 XF101-2 XF137-2 XF152-2 Qdot® 585 filter set (20 nm EM; 32004) (460SPUV / 475DCXRU / D585 / 20nm) Qdot® 585 filter set (40 nm EM; 32008) (460SPUV / 475DCXRU / D585 / 40nm) R-PE (41003) Rhodamine LP (41032) FITC/PI (41016)
565 XF302 Qdot® 565 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 565WB20 XF104-2 XF105-2 Qdot® 565 filter set (20 nm EM; 32005) (460SPUV / 475DCXRU / D565 / 20nm) Qdot® 565 filter set (40 nm EM; 32009) (460SPUV / 475DCXRU / D565 / 40nm) Eosin (41011) Cascade Yellow™ (31038) JP2 (YGFP with EGFP; 31040) Auramine (31015)
525 XF301 Qdot® 525 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 525WB20 XF100-3 XF100-2 XF115-2 XF89-2 Qdot® 525 filter set (20 nm EM; 32006) (460SPUV / 475DCXRU / D525 / 20nm) Qdot® 525 filter set (40 nm EM; 32010) (460SPUV / 475DCXRU / D525 / 40nm) FITC / RSGFP / Bodipy® / Fluo-3 / DiO (41001) FITC / RSGFP longpass (40012) BFP to GFP FRET (31032) BFP to GFP FRET wide excitation (31034) GFP wide blue excitation (31054)
All colors† XF300 Qdot® filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitters: 800WB80, 840WB80, 710AF40, 655WB20, 605WB20, 585WB20, 565WB20, 525WB20 XF129-2 XF130-2 Qdot® Multiple Emission Set (71014) (460SPUV, 475DCXRU, D525/20nm, D605/20nm, D565/20nm, D585/20nm) UV (11000V2) Blue/Violet (11003V2) UV/Violet (11011V

† Useable filter sets will usually provide substantially lower signal than optimal filter sets; sensitive applications will generally require the optimal filter sets. ?705 and 800 nm Qdot® nanocrystal emission cannot be seen by eye and must be detected with an IR-sensitive detector. ?For viewing multiple colors of Qdot® nanocrystals through microscope eyepieces.

Temperature Stability

Fluorescence is not temperature dependent.
Temperature Recommendation
<=0°C NEVER freeze Qdot® nanocrystals - polymer induces aggregation at freezing temperatures.
>=4°C Core/Shell/Polymer stable at 4°C for ~ 6 months. May be filter sterilized using uncharged filters.
<=60°C Core/Shell/Polymer stable at 60°C (as in in situ hybridization).
<=65°C Core/Shell/Polymer stable at 65°C for only ~1 hour, beyond 1 hour emission drops off.
<=100°C Core/Shell/Polymer stable up to 100°C brief exposure. OK for 5 minutes at 100°C.
<=360°C Only Core/Shell stable up to 360°C.

Solvent Stability

Chemical Stability/Instability Comments
Acetonitrile Unstable Promotes precipitation.
Alcohols OK up to <10% Qdot® nanocrystal start to self-aggregate in solutions with >10% alcohol. Alcohols do not degrade or damage nanocrystals, only promote their aggregation in solution.
Alkanes Stable Core/shell only dispersible in alkanes; Core/shell/polymer stable in alkanes, but not soluble in alkanes.
Cacodylate (arsenic-based buffer) Unknown  
Chloroform Unstable Core/Shell not stable in chloroform in the light, signal drops; photodegradation will occur and fluorescence will be lost. Higher concentrations of nanocrystals and keeping in dark will help but cannot prevent photodegradation.
DMF Stable  
DMSO Stable  
Detergents Stable OK up to 5% Tween
  Stable OK up to 4% Saponin
  Unknown Triton X-100 Unknown
  Unknown NP-40 Unknown
Formaldehyde/Paraformaldehyde Unknown Works fine for FA/PFA fixed samples, AFTER samples washed with buffers.
Formalin Unknown Qdot® nanocrystals may be applied to formalin- or glutaraldehyde-fixed samples, but only after the samples have been rinsed with buffer to remove all fixative.
Glutaraldehyde Unknown Qdot® nanocrystals may be applied to formalin- or glutaraldehyde-fixed samples, but only after the samples have been rinsed with buffer to remove all fixative.
Glycerol OK up to 50% Some aggregation at higher concentrations.
H2O2 Unstable  
Heavy Metals Variable Some are OK; Copper quenches.
MgCl2 Stable Some aggregation/precipitation at higher concentrations (ions shielding charges).
Marine salt (sea salt concentrations) OK Unknown for higher concentrations of salts, such as the Dead Sea or the Great Salt Lake; higher, non-biological levels of salts shield charges on non-PEG polymer surface and promote aggregation; "ITK" products more susceptible. PEG/polymer Qdot® are OK to high salt (oceanic) concentrations.
NaCl Stable up to 1 M Antibody conjugates are stable up to 0.5-1 M; aggregate at higher concentrations.
NaI Stable up to 1 M Same behavior as NaCl
Paraffin-embedding Stable Qdot® nanocrystals are stable to typical paraffin-embedding methods and subsequent deparaffinization, dehydration by alcohols/organic solvents and rehydration.
PBS Buffer Unstable Diluted in 1X PBS, see loss of signal after 30 min to 1 hour. Concentrated solutions of nanocrystals OK in PBS.
Phenol Unknown  
Picric Acid Unknown  
ProLong Unstable Quenches Qdot® nanocrystals
"PAP Pens" Most quench Qdot® Some quench Qdot® nanocrystal fluorescence (Crystal violet, and possibly other components, is a quencher). Vector Labs ImmEdge PAP Pen is OK.
Organic solvents Stable Core/shell hydrophobic; hydrophilic polymer promotes aggregation in organic solvents. Overall, the nanocrystals (core/shell/polymer) are not degraded by organic solvents; this does not hold for proteins or other biomolecules conjugated to the surface of the nanocrystals.
Sodium azide Stable We ship conjugates with 0.05% NaN3
Thimerosal Unknown  
Xylene Stable  

Antibody Labeling with Organic Dyes vs Qdot® Nanocrystals

Organic Dye Antibody Conjugate

  • Typical fluorescent dye labeled IgG
  • Image showing approximate number of dyes per IgG

Qdot Antibody Conjugate

  • Typical Qdot nanocrystal labeled with IgG
  • Image showing approximate number of antibodies per particle