Problem of Diminished cRGD Surface Activity and What Can Be Done about It

Michael C. Robitaille, Joseph A. Christodoulides, Jinny Liu, Wonmo Kang, Jeff M. Byers, Marc P. Raphael

Research output: Contribution to journalArticlepeer-review

Abstract

RGD peptides play a pivotal role in growing and diverse areas of biological research, ranging from in vitro experiments probing fundamental molecular mechanisms of cell adhesion to more applied in vivo strategies in medical imaging and cancer therapeutics. To better understand the outcomes of RGD-based approaches, we quantified the degree to which cyclic RGD (cRGD) activity is blocked by nonspecific binding of commonly used medium constituents. First, we show that recombinant αVβ3 integrins can be used as a highly sensitive cell-free sensor to quantitatively and reliably characterize the activity of cRGD-functionalized surfaces via surface plasmon resonance (SPR). Next, SPR experiments were utilized to measure the extent of blocking of cRGD-functionalized surfaces by the commonly used agents BSA, PLL-g-PEG, and fetal calf serum (FCS)-supplemented media, using recombinant αVβ3 integrin as a probe for cRGD binding activity in the presence of blocking agents. All three additives were highly efficient blockers of cRGD activity, as exemplified by cell culture media containing 1% FCS which reduced the cRGD activity by 33-fold. We then developed a strategy to combat these deleterious effects by employing the recombinant integrins as a protective cap. We show that the unblocked cRGD activity can be preserved in the presence of PLL-g-PEG by employing the αVβ3 integrin as a removable protective cap, both in cell-free and in vitro experiments. In vitro studies with MDA-MB-231 cells cultured atop cRGD-functionalized surfaces found that cell adhesion and migration prevented by PLL-g-PEG were restored when this protective cap approach was used.

Original languageEnglish (US)
Pages (from-to)19337-19344
Number of pages8
JournalACS Applied Materials and Interfaces
Volume12
Issue number17
DOIs
StatePublished - Apr 29 2020

Keywords

  • PEG
  • cRGD
  • cell adhesion
  • cell migration
  • integrins
  • serum
  • surface activity
  • surface plasmon resonance

ASJC Scopus subject areas

  • Materials Science(all)

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