S23 surfactant/Pluronic L64/Pluronic 184 /Poloxamer 184

Average molecular weight: 2900

Turbidity point (1% aqueous solution) : 57~61

HLB value: 13

CAS: 9003-11-6

Pluronic L64 (Poloxam 184) is a non-ionic triblock copolymer surfactant consisting of alternating hydrophilic polyoxyethylene (PEO) segments with hydrophobic polyoxyethylene (PPO) segments (Structural form: PEO₁₃-PPO₃₀-PEO₁₃). Its unique "amphiphilicity" and biocompatibility make it a multifunctional excipient in vitro diagnostic reagents, especially for systems that need to stabilize biomolecules, optimize fluid properties, and be compatible with whole blood tests.

Action mechanism

Non-hemolytic: mild action on the red cell membrane, suitable for whole blood direct detection (such as chromatographic strips, microfluidic chips), to avoid hemolysis interference with optical signals.

Colloidal protection and stability: The hydrophobic PPO chain is adsorbed to the surface of particles (such as colloidal gold, latex microspheres), and the hydrophilic PEO chain forms 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 microplate, 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.

Antifoam and antistatic: inhibit foam formation in the process of reagent mixing or automatic sample addition, and reduce the accumulation of particles caused by electrostatic adsorption.

Application scenario

Immunochromatographic strip: Added to the binding pad treatment solution to stabilize colloidal gold labeled antibodies and improve the uniformity of color signal (such as hCG detection).

Latex enhanced immunoturbidity: Premix in latex microsphere suspension to enhance particle dispersion and optimize turbidity signal of antigen-antibody complex.

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

Enzyme reaction system stabilizer: as a component of enzyme preservation solution, 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.

General use range: 0.01%-1.0% (0.05%-0.2% commonly used in diagnostic reagents).

Matters needing attention

Solubility: Low temperature (<15℃) may form a gel, need to be heated to 25-30 ℃ and stirred until clear after use.

Temperature sensitivity: Long-term exposure to >50 ° C may lead to molecular chain breakage.

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

Q&A

Colloidal gold accumulation: may be insufficient concentration or incomplete dissolution; It is recommended to increase to 0.1-0.2% to ensure complete dissolution after use.

Too slow chromatographic speed: may be insufficient wettability or viscosity is too high; It is recommended to optimize the concentration (0.05%-0.1%) or add a low viscosity buffer.

Loss of activity after lyophilization: may be improper ratio of protective agent; It is recommended that Pluronic L64 be increased to 0.5% to 1% and compounded with trehalose.

Reagent turbidity: may be low temperature precipitation or ionic strength is too high; It is recommended to preheat to room temperature and swirl well, or adjust salt concentration.

Note: Pluronic L64's balance properties (wettability, stability, and biosafety) make it an ideal choice for a highly sensitive, whole-blood compatible diagnostic reagent, but its effects need to be quantified by tools such as dynamic light scattering (DLS), freeze-drying microscopy, and optimized formulations based on specific reagent systems (e.g. antibody properties, reaction vectors). For higher wettability, it can be combined with Surfynol series surfactants.

Pluronic/Poloxamer is made by BASF