Synthesis of Short Peptides with Perfluoroalkyl Side Chains and Evaluation of Their Cellular Uptake Efficiency

Abstract

With an increasing demand for macromolecular biotherapeutics, the issue of their poor cell‐penetrating abilities requires viable and relevant solutions. Herein, we report tripeptides bearing an amino acid with a perfluoroalkyl (RF) group adjacent to the α‐carbon. RF‐containing tripeptides were synthesized and evaluated for their ability to transport a conjugated hydrophilic dye (Alexa Fluor 647) into the cells. RF‐containing tripeptides with the fluorophore showed high cellular uptake efficiency and none of them were cytotoxic. Interestingly, we demonstrated that the absolute configuration of perfluoroalkylated amino acids (RF‐AAs) affects not only nanoparticle formation but also the cell permeability of the tripeptides. These novel RF‐containing tripeptides are potentially useful as short and noncationic cell‐penetrating peptides (CPPs).

Asymmetric α-Fluoroalkyl-α-Amino Acids: Recent Advances in Their Synthesis and Applications

“…The coupling of β,β-difluoroalanine can be achieved at its N -terminal position using the EDC/oxyma activation [ 44 ]. Glycine with a perfluoroalkylated side chain was recently incorporated in a peptide chain using the COMU/Oxyma system [ 99 ]. However, the peptide coupling reactions at the N -terminal position of α-Tfm-amino acids, especially the hindered quaternarized ones, such as α-Tfm-alanine, required the activation of the amino acid as an acid halide or a mixed anhydride.…”

“…Very recently, the high ability of perfluoroalkylated chain-containing tripeptides to transport a hydrophilic dye (Alexa Fluor 647) into cells has been reported [ 99 ]. This could constitute an interesting strategy for the design of fluorinated drug delivery carriers.…”

“… Selected examples of N -terminal position peptide coupling reactions of α-Tfm-amino acids [ 44 , 98 , 99 , 100 , 101 ]. …”

“…In a similar manner, the PAMPA method has been recently used to demonstrate that a CH 3 to CF 3 substitution is a useful strategy for increasing the membrane permeability of di-and tri-peptides (Figure 8) [114]. Very recently, the high ability of perfluoroalkylated chain-containing tripeptides to transport a hydrophilic dye (Alexa Fluor 647) into cells has been reported [99]. This could constitute an interesting strategy for the design of fluorinated drug delivery carriers.…”