pH Ranges for Qdot® Nanocrystals

pH Recommendations
>9Not recommmended- Qdot® nanocrystals start to self-aggregate/clump.
(Qdot® nanocrystals are not degraded by basic pH. )
>6 to <9Qdot® nanocrystals most optimal stability in this pH range.
>5 to <6Marginal stability is shown in this range
<4Not 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: 800WB80XF308 Qdot® 800 filter set for multiplexing Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 840WB80Qdot® 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: 710AF40XF140-2 XF70 XF110-2 XF141-2 XF48-2Qdot® 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)
655XF305 Qdot® 655 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 655WB20XF102-2 XF40-2 XF42 XF45Qdot® 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)
605XF304 Qdot® 605 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 605WB20XF108-2 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)
585XF303 Qdot® 585 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 585WB20XF101-2 XF137-2 XF152-2Qdot® 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)
565XF302 Qdot® 565 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 565WB20XF104-2 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)
525XF301 Qdot® 525 filter set Exciter 1: 425DF45 or Exciter 2: 415WB100 Dichroic: 475DCLP Emitter: 525WB20XF100-3 XF100-2 XF115-2 XF89-2Qdot® 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, 525WB20XF129-2 XF130-2Qdot® 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°CNEVER freeze Qdot® nanocrystals - polymer induces aggregation at freezing temperatures.
>=4°CCore/Shell/Polymer stable at 4°C for ~ 6 months. May be filter sterilized using uncharged filters.
<=60°CCore/Shell/Polymer stable at 60°C (as in in situ hybridization).
<=65°CCore/Shell/Polymer stable at 65°C for only ~1 hour, beyond 1 hour emission drops off.
<=100°CCore/Shell/Polymer stable up to 100°C brief exposure. OK for 5 minutes at 100°C.
<=360°COnly Core/Shell stable up to 360°C.

Solvent Stability

Chemical Stability/Instability Comments
AcetonitrileUnstablePromotes precipitation.
AlcoholsOK 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.
AlkanesStableCore/shell only dispersible in alkanes; Core/shell/polymer stable in alkanes, but not soluble in alkanes.
Cacodylate (arsenic-based buffer) Unknown 
ChloroformUnstableCore/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.
DMFStable 
DMSOStable 
DetergentsStableOK up to 5% Tween
 StableOK up to 4% Saponin
 UnknownTriton X-100 Unknown
 Unknown NP-40 Unknown
Formaldehyde/ParaformaldehydeUnknownWorks fine for FA/PFA fixed samples, AFTER samples washed with buffers.
FormalinUnknownQdot® nanocrystals may be applied to formalin- or glutaraldehyde-fixed samples, but only after the samples have been rinsed with buffer to remove all fixative.
GlutaraldehydeUnknownQdot® nanocrystals may be applied to formalin- or glutaraldehyde-fixed samples, but only after the samples have been rinsed with buffer to remove all fixative.
GlycerolOK up to 50%Some aggregation at higher concentrations.
H2O2Unstable 
Heavy MetalsVariable Some are OK; Copper quenches.
MgCl2StableSome aggregation/precipitation at higher concentrations (ions shielding charges).
Marine salt (sea salt concentrations) OKUnknown 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.
NaClStable up to 1 MAntibody conjugates are stable up to 0.5-1 M; aggregate at higher concentrations.
NaIStable up to 1 MSame behavior as NaCl
Paraffin-embeddingStableQdot® nanocrystals are stable to typical paraffin-embedding methods and subsequent deparaffinization, dehydration by alcohols/organic solvents and rehydration.
PBS BufferUnstableDiluted in 1X PBS, see loss of signal after 30 min to 1 hour. Concentrated solutions of nanocrystals OK in PBS.
PhenolUnknown 
Picric AcidUnknown 
ProLongUnstableQuenches 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 solventsStableCore/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 azideStableWe ship conjugates with 0.05% NaN3
ThimerosalUnknown  
XyleneStable  

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