Efficient decoration of nanoparticles intended for intracellular drug targeting with targeting residues, As revealed by a new indirect analytical Approach

Veronika Kaplun, David Stepensky

Research output: Contribution to journalArticlepeer-review


In our previous studies, we developed a nanodrug delivery system (nano-DDS) based on poly(lactic-co-glycolic acid) PLGA nanoparticles encapsulating antigenic peptide and fluorescent marker and 3-stage approach for its decoration with peptide targeting residues. The objectives of this study were (a) to develop methods for quantitative analysis of efficiency of individual conjugation steps and (b) to determine, based on these methods, the efficiency of our 3-stage approach of nano-DDS decoration. We prepared antigenic peptide-loaded PLGA-based nano-DDSs and sequentially decorated them with specific residues using carbodiimide and Click (azide-alkyne Huisgen cycloaddition using copper(I) catalysis) reactions. The extent of cargo encapsulation and release kinetics were analyzed using HPLC-based and colorimetric analytical methods. The efficiency of residue conjugation to the nano-DDSs was analyzed using FTIR spectroscopy and by quantifying the unreacted residues in the reaction mixture (i.e., by indirect analysis of reaction efficiencies). We revealed that copper, the catalyst of the Click reactions, formed complexes with unreacted targeting residues and interfered with the analysis of their conjugation efficiency. We used penicillamine (a chelator) to disrupt these complexes, and to recover the unreacted residues. Quantitative analysis revealed that 28,800-34,000 targeting residues (corresponding to 11-13 nm2 surface area per residue) had been conjugated to a single nano-DDS using our 3-stage decoration approach, which is much higher than previously reported conjugation efficiencies. We conclude that the applied analytical tools allow quantitative analysis of nano-DDSs and the efficiency of their conjugation with targeting residues. The 3-stage decoration approach resulted in dense conjugation of nano-DDSs with targeting residues. The present decoration and analytical approaches can be effectively applied to other types of delivery systems and other targeting residues.

Original languageAmerican English
Pages (from-to)2906-2914
Number of pages9
JournalMolecular Pharmaceutics
Issue number8
StatePublished - 4 Aug 2014


  • Click chemistry
  • conjugation of targeting residues
  • intracellular targeting
  • nanoparticle formulations
  • targeted drug delivery

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery


Dive into the research topics of 'Efficient decoration of nanoparticles intended for intracellular drug targeting with targeting residues, As revealed by a new indirect analytical Approach'. Together they form a unique fingerprint.

Cite this