Direct solid-phase peptide synthesis on chitosan microparticles for targeting tumor cells

Abstract

An EGFR-targeting peptide with Ala-Glu-Tyr-Leu-Arg sequence was assembled directly onto the surface of spray-dried chitosan microparticles using solid-phase peptide synthesis with Fmoc chemistry. Both targeted and scrambled peptides were cleaved from chitosan with enzymatic digestion, isolated using reversed-phase HPLC, then identified with LC/MS/MS and amino acid analysis. Particles with conjugated peptides and fluorescent-labeled were characterized for binding with A549 (cancer) and WI-26 VA4 (normal) lung cells using flow cytometry and confocal microscopy. The purity of peptide synthesis was in the range of 74–77%. The cell binding studies revealed that particles modified with the peptide bind to lung cancer cells 8.3 times higher than the normal lung cells. The binding potential of surface-modified targeted particles to the tumor cells was compared with scrambled and unmodified ones and was found to be significantly different. The binding was 7.3–7.5-fold higher than the scrambled and unmodified particles, respectively. Modification of chitosan particles with direct assembly of Ala-Glu-Tyr-Leu-Arg peptide on their surface enhanced their targeting potential to lung cancer cells and could be used as a potential carrier for delivery and therapy. This approach can further be utilized for assembly of other short peptide ligands on micro- or nanoparticulate systems for tumor targeting.