Light-directed simultaneous synthesis of oligopeptides on microarray substrate using a photogenerated acid

Area of Science:

• Chemical Synthesis
• Biotechnology
• Materials Science

Background:

• Deprotection is a critical step in solid-phase peptide synthesis.
• Trifluoroacetic acid (TFA) is commonly used but can be harsh.
• Developing milder, site-specific deprotection methods is essential for complex peptide synthesis.

Purpose of the Study:

• To evaluate photogenerated acid (PGA) as a deprotection agent in oligopeptide synthesis.
• To compare PGA with traditional deprotection agents like TFA.
• To demonstrate the accuracy and efficiency of light-activated PGA synthesis on a microarray.

Main Methods:

• Comparative deprotection study using PGA, trisarylsulfonium antimonyhexafluoride (SSb), and TFA on glass slides.
• In situ generation of PGA via light activation of a precursor molecule on a microwell substrate.
• Mask-less laser light illumination for precursor activation.
• Validation using lead(II) ion-peptide biosensor and p53 peptide-antibody binding assays on an oligopeptide microarray.

Main Results:

• PGA demonstrated comparable efficiencies to TFA in the deprotection step.
• Light-activated PGA enabled accurate synthesis of specific amino acid sequences at defined locations.
• Oligopeptide microarray analysis confirmed specific binding and correct localization through fluorescence imaging.
• Stepwise synthesis efficiencies for pentapeptide synthesis ranged from 96-100% and remained consistent with increasing peptide chain length.

Conclusions:

• Photogenerated acid (PGA) is a viable and efficient alternative to TFA for oligopeptide synthesis.
• Light-activated in situ acid generation offers precise control over deprotection in microarray synthesis.
• This method enables accurate, high-efficiency synthesis of peptides with validated sequence and location.