Qdot® Nanocrystal Facts and Hints
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
- Typical fluorescent dye labeled IgG
- Image showing approximate number of dyes per IgG
- Typical Qdot nanocrystal labeled with IgG
- Image showing approximate number of antibodies per particle