Successful strategies for the attachment of oligopeptides to mesoporous silica with pores large enough to load biomolecules should utilize the high surface area of pores to provide an accessible, protective environment. A two-step oligopeptide functionalization strategy is examined here using diazirine-based heterobifunctional linkers. Mesoporous silica nanoparticles (MSNPs) with average pore diameter of ~8 nm and surface area of ~730 m2/g were synthesized and amine-functionalized. Tetrapeptides Gly-Gly-Gly-Gly (GGGG) and Arg-Ser-Ser-Val (RSSV), and a peptide comprised of four copies of RSSV (4RSSV), were covalently attached via their N-terminus to the amine groups on the particle surface by a heterobifunctional linker, sulfo-succinimidyl 6-(4,4′-azipentanamido)hexanoate (sulfo-NHS-LC-diazirine, or SNLD). SNLD consists of an amine-reactive NHS ester group and UV-activable diazirine group, providing precise control over the sequence of attachment steps. Attachment efficiency of RSSV was measured using fluorescein isothiocyanate (FITC)-tagged RSSV (RSSV-FITC). TGA analysis shows similar efficiency (0.29, 0.31 and 0.26 mol peptide/mol amine, respectively) for 4G, RSSV and 4RSSV, suggesting a generalizable method of peptide conjugation. The technique developed here for the conjugation of peptides to MSNPs provides for their attachment in pores and can be translated to selective peptide-based separation and concentration of therapeutics from aqueous process and waste streams.
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This research was funded by the United States National Institutes of Health (NIH), grant numbers R41AT008312 and 2R44AT008312-02; and Kentucky Science and Engineering Foundation, grant number KSEF-2929-RDE-016. This work was performed in part at the University of Kentucky Electron Microscopy Center, a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (NNCI-2025075).
The data presented in this study are available on request from the corresponding authors.
The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/nano12040608/s1
Khan, Md Arif; Ghanim, Ramy W.; Kiser, Maelyn R.; Moradipour, Mahsa; Rogers, Dennis T.; Littleton, John M.; Bradley, Luke H.; Lynn, Bert C.; Rankin, Stephen E.; and Knutson, Barbara L., "Strategy for Conjugating Oligopeptides to Mesoporous Silica Nanoparticles Using Diazirine-Based Heterobifunctional Linkers" (2022). Chemical and Materials Engineering Faculty Publications. 84.