Effect of redox-responsive DTSSP crosslinking on poly(l-lysine)-grafted-poly(ethylene glycol) nanoparticles for delivery of proteins

Biotechnol Bioeng. 2020 Aug;117(8):2504-2515. doi: 10.1002/bit.27369. Epub 2020 Jun 8.


Therapeutic proteins are utilized in a variety of clinical applications, but side effects and rapid in vivo clearance still present hurdles. An approach that addresses both drawbacks is protein encapsulation within in a polymeric nanoparticle, which is effective but introduces the additional challenge of destabilizing the nanoparticle shell in clinically relevant locations. This study examined the effects of crosslinking self-assembled poly(l-lysine)-grafted-poly(ethylene glycol) nanoparticles with redox-responsive 3,3'-dithiobis(sulfosuccinimidyl propionate) (DTSSP) to achieve nanoparticle destabilization in a reductive environment. The polymer-protein nanoparticles (DTSSP NPs) were formed through electrostatic self-assembly and crosslinked with DTSSP, which contains a glutathione-reducible disulfide. As glutathione is upregulated in various cancers, DTSSP NPs could display destabilization within cancer cells. A library of DTSSP NPs was formed with varying copolymer to protein (C:P) and crosslinker to protein (X:P) mass ratios and characterized by size and encapsulation efficiency. DTSSP NPs with a 7:1 C:P ratio and 2:1 X:P ratio were further characterized by stability in the presence proteases and reducing agents. DTSSP NPs fully encapsulated the model protein and displayed 81% protein release when incubated with 5 mM dithiothreitol for 12 hr. This study contributes to understanding stimulus-responsive crosslinking of polymeric nanoparticles and could be foundational to clinical administration of therapeutic proteins.

Keywords: DTSSP crosslinking; nanoparticle drug delivery; redox-responsive; stimulus-responsive; therapeutic protein delivery.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cross-Linking Reagents / chemistry
  • Drug Carriers / chemistry*
  • Nanoparticles / chemistry*
  • Oxidation-Reduction
  • Polyethylene Glycols / chemistry*
  • Polylysine / chemistry*
  • Proteins / chemistry
  • Succinimides / chemistry*


  • Cross-Linking Reagents
  • Drug Carriers
  • Proteins
  • Succinimides
  • Polylysine
  • Polyethylene Glycols
  • 3,3'-dithiobis(sulfosuccinimidyl propionate)