Static light scattering instrument for rapid and time-resolved particle sizing in polymer and colloid solutions

Abstract

A static light scattering instrument capable of time‐resolved intensity measurements for polymers and colloids in dilute solution is described. An optical multichannel analyzer reports, with an ultimate time resolution of 15 ms, the scattered intensity in any angular range spanning 40°. Data acquisition software allows for the rapid collection of intensity data in a timed sequence. This instrument is especially useful for following size changes in large (≳∼30 nm) polymers or colloids. The instrument has been applied successfully to study the interaction of an antimicrobial peptide, (KLAKKLA)₃, with large unilamellar vesicles composed of dioleoylphosphatidylcholine (DOPC). For a 10:1 lipid to peptide ratio (KLAKKLA)₃ induces a 20% increase in the average radius of a DOPC vesicle suspension. The interaction is complete within 5 min, but most of the change occurs in the first 200 s after peptide addition.