S2 surfactant/Kolliphor P188/Pluronic F-68/Poloxamer 188

Appearance: White to yellowish waxy particles or powder

pH value (2.5% solution) : 6.0~7.5

Molecular weight (calculated by hydroxyl value) : 7680 ~ 9510

Soluble in ethanol, water (solution has opal light), insoluble in ether, paraffin oil and fat oil.

CAS: 9003-11-6

S2 surfactant, also known as Poloxamer 188, Kolliphor P188/Pluronic F-68/Poloxamer 188 is a non-ionic block copolymer surfactant, consisting of a hydrophilic polyoxyethylene (PEO) segment alternating with a hydrophobic polyoxyethylene (PPO) segment (structure formula: Peo-po-peo). Its unique amphiphilicity and biocompatibility make it a multifunctional excipient in in vitro diagnostic reagents, which is widely used in stabilizing biomolecules, improving fluid properties and optimizing reaction interfaces.

Action mechanism

Biocompatibility: As a pharmaceutical excipient, non-toxic, non-immunogenic, can directly contact blood/cells, suitable for whole blood or live cell detection system.

Colloidal protection and stability: adsorption to the surface of particles (such as colloidal gold, latex microspheres) through hydrophobic chains, hydrophilic chains form steric hindration to prevent aggregation and precipitation.

Interfacial activity and wetting: reduce the liquid-solid interfacial tension, promote the uniform diffusion of samples in the test strip or microfluidic chip, and reduce the edge effect.

Anti-protein adsorption: Block the non-specific adsorption of proteins/cells on solid phase carriers (such as cellulose nitrate membranes, microporous plates) to reduce background interference.

Lyophilization protection: Maintenance of enzyme/antibody activity during lyophilization to prevent ice crystal damage (alternative to traditional sugar protectants).

Application scenario

Colloidal gold/latex reagent stabilization: added to the marker complex solution to prevent particle aggregation and enhance the uniformity of the color signal (such as chromatographic test strips).

Whole blood direct detection: Adding sample diluent to inhibit red blood cell aggregation and improve plasma separation efficiency (such as CRP and blood glucose detection).

Enzyme reaction system stability: as an enzyme preservation solution component, reduce enzyme inactivation caused by high temperature or repeated freezing and thawing (such as PCR reagent, chemiluminescence system).

Microfluidic chip wetting agent: Pre-applied to hydrophobic channels to optimize blood/reagent flow performance and avoid bubble retention.

Freeze-dried protectants: Combined with sugars (such as trehalose) to protect antibody/antigen activity and extend the shelf life of reagents.

General use range: 0.01%-1.0% (gradient test required, low concentration preferred).

Matters needing attention

Dissolution method:It should be slowly heated (40-50 ℃) and stirred until completely dissolved to avoid local gelation (difficult to dissolve in cold water).

Temperature sensitivity:Long-term storage at high temperature (>50℃) may lead to molecular chain breakage and decreased activity.

Compatibility test:Avoid direct mixing with strong oxidants (such as high concentrations of hydrogen peroxide) or organic solvents (such as chloroform).

Pluronic Fmur68 is made by BASF.