Technical FAQs
In a solution containing hydrophobic dyes, polystyrene particles will expand. Afterwards, this dye can diffuse into the polystyrene matrix. Then the particles are removed from the solvent and dialyzed into the aqueous phase environment, expanding in reverse and embedding the dye into the polystyrene. After the dye is embedded in polystyrene, it will be properly isolated from the external environment.
We have not determined the specific number of dye molecules in each particle. The number of dye molecules is a variable related to the particle diameter and the properties of the dye.
The concentration of particles and other related parameters can generally be found in the corresponding product manual. Most of the instruction manuals can be found on the product webpage. If you can't find it on the webpage, please contact customer service.
We recommend using the method of dialysis with a molecular weight cut-off of 500,000 MWCO to remove sodium azide from the buffer containing particles.
The stability of particles in alcohols or water/alcohol mixtures depends on the chain length of the alcohols. Particles are quite stable in 40% methanol, but they are more soluble in long-chain alcohols. Long-term storage of particles in solvents containing alcohols can lead to the dissolution of dyes.
Fluorescent particles may contain trace amounts of surfactants. Only latex particles with a diameter greater than 100 nm contain no surfactants at all.
We recommend using surface-modified particles within the following pH ranges:
Modifying group\tAvailable pH range
Aldehyde/Sulfate\t≥3 and ≤12
Amino\t ≤9
Carboxyl\t ≥6 and ≤12
Sulfate\t ≥3 and ≤12
Unless the particles have been frozen, aggregation is usually reversible under normal circumstances. Before use, the particles can be dispersed by ultrasonic treatment in a water bath ultrasonic instrument. If particles are not used in the living cell system, a low concentration of Tween 20 or Triton X-100 can also be added. For protein-labeled particles, the mildest possible methods should be used to disperse the aggregates to avoid disrupting the protein conformation.
Note: The smaller the particle size of the particles is, the more likely they are to aggregate.
No.
This situation is normal. The foam is caused by Tween 20, which plays a role in preventing aggregation in the reservoir.
It is not sterile and can be filtered through a membrane before use.
It is recommended to use a water bath ultrasound instrument to disperse aggregates. Do not use the probe ultrasound instrument, otherwise the particles will be damaged.
All kinds of conditions may lead to the aggregation of particles. Please try to avoid the particles coming into contact with the following environments:
①Freezing temperature
② Microbial contamination
③ High-salt buffer solution
④ Extreme pH: Acidic pH can neutralize carboxyl and sulfonate matrix. An alkaline pH will deprotonate the amino group.
⑤ Heating, excessive vortexing and excessive ultrasonic treatment: Special attention should be paid to protein-labeled particles.
Non-specific binding can be alleviated by blocking solution.
Even short-term freezing can lead to irreversible aggregation and may cause deformation of the particles, making them unusable.
Centrifugation is not an effective method for collecting smaller particles; Even though small precipitates can be seen, there are still quite a few particles remaining in the solution. For particles with a diameter of less than 1 μm, we recommend using any of the following methods for washing:
①Cross-flow filtration is carried out because these particles have extremely high compression coefficients and can withstand high gravity without the risk of damage.
② Using 500 kDa MWCO to intercept molecular weight for dialysis.
Note: Particles with a diameter greater than 1 μm can be centrifuged at 1,300 rpm.
Bacterial contamination is the most common cause that makes particles unusable. Many of our particles contain low levels of sodium azide to prevent bacterial contamination, but this still happens sometimes. The best way to assess bacterial contamination is to perform electroplating on an appropriate medium and conduct an inspection after 72 h.
PE particles were prepared by the template method, PS was used as the framework, and the PE content was above 75%. At present, 100% pure PE particles cannot be provided. There is also the crosslinking agent divinylbenzene. Therefore, the density will be large. Cross-linking will lead to a higher density.
No.
PVC wrapping.