EDC-NHS coupling method is ideal for conjugating short peptides or amino acids to nanoparticles with -COOH or -NH2 groups due to its high efficiency, specificity, and mild reaction conditions. EDC activates -COOH groups, forming a reactive intermediate that NHS stabilizes into an ester, which selectively reacts with -NH2 groups. This method provides high conjugation yield, preserves biomolecule integrity, works with various nanoparticles, and minimizes side reactions, making it versatile and reliable for bioconjugation.

https://blog.papyrusbio.com/edc-bioconjugation/

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@shiwachaubey But my doubt is that doesn't this activated COOH can attack the NH2 groups in the peptides itself, there by reducing yield of the desired product.

To prevent peptide-peptide crosslinking during EDC-NHS coupling, temporarily protect the -NH₂ groups in peptides using Fmoc or Boc, which can be removed later. Pre-activate the nanoparticle’s -COOH groups with EDC and NHS, then add peptides to avoid free activated -COOH in solution. Use an excess of nanoparticle functional groups to ensure selective reactions with peptides. Conduct the reaction at low peptide concentrations and maintain the pH between 6 and 7.5 to reduce self-reactions. Introducing a linker like PEG between the nanoparticle and peptide can also help. If possible, alternative chemistries like maleimide-thiol or click reactions can provide higher specificity. Finally, purify the product using techniques like chromatography or dialysis to remove crosslinked byproducts and improve yield

@shiwachaubey thank you so much.