Application note: Purification of nanoparticles by Hollow Fibre Diafiltration

Hollow Fibre Diafiltration is rapid alternative to traditional methods of nanoparticle purification like ultracentrifugation.

An efficient and rapid alternative to current purification methods

Diafiltration can be used to purify a wide range of nanoparticles including liposomes, colloids, magnetic particles and nanotubes. Hollow Fibre Diafiltration is a membrane based method where pore size determines the retention or transmission of solution components. During the process the sample is gently circulated through a tubular membrane. With controlled replacement of the permeate or (dialysate), pure nanoparticles can be attained. Hollow Fibre Diafiltration can be directly scaled up from R&D volumes to production by adding more membrane fibres and maintaining the operating parameters.

In this study a 100kD polysulfone hollow fibre module was selected based upon the unreacted by-product molecular weight (<50kD) and the polymeric nanoparticle (250kD). The geometry of the hollow fibre helps particle purification applications due to the phenomenon known as tubular pinch effect, where particles migrate to the center of the hollow fibre where flow velocity is the highest. Discontinuous diafiltration was selected for the application due to high viscosity, 500cps. A bench scale Tangential Flow Filtration system with data acquisition software and pressure indicator (Spectrum Labs KrosFlo® Research IIi) was used for the process.