Characteristics of Cell-Penetrating Peptide/Nucleic Acid Nanoparticles

Abstract

Nucleic acids are highly promising candidates for the treatment of various genetic diseases. However, due to the large size and negative charge, nucleic acids are not efficiently taken up by cells, and thus, their clinical potential remains limited so far. Therefore, various delivery vehicles have been designed to assist the cellular uptake of nucleic acids. Among these, cell-penetrating peptides (CPPs) have gained increasing popularity as efficient and nontoxic delivery vectors. CPPs can be coupled to nucleic acids either by covalent or noncovalent association. Noncovalent coupling, which is based on the formation of nanoparticle-like nanocomplexes (NP), has received much attention in recent years, and the number of studies employing the strategy is explosively increasing due to the high therapeutic potential. However, the properties of CPP/nucleic acid NPs have not been characterized in sufficient detail yet. We performed a comprehensive analysis of the size and morphology of nucleic acid nanoparticles with novel transfection peptides, PepFects (PFs) and NickFects (NFs), using negative staining transmission electron microscopy (TEM). In addition, we examined whether the attachment of fluorescence or (nano)gold label to nucleic acid affects the nanocomplex formation or its morphology. We demonstrated that transportan-10-based new generation CPPs from PF and NF families condense nucleic acids to NPs of homogeneous size and shape. The size and shape of assembled nanoparticles depend on the type of the complexed nucleic acid and the sequence of the used peptide, whereas the label on the nucleic acid does not influence the gross characteristics of formed NPs.

Identification of a Short Cell-Penetrating Peptide from Bovine Lactoferricin for Intracellular Delivery of DNA in Human A549 Cells

“…Small polar molecules, such as ions, amino acids, and monosaccharides, are able to enter cells through specific carriers or channels in the plasma membrane. The intrinsic nature of cellular membranes precludes influx of macromolecules, such as DNAs, RNAs, and proteins [ 1 ]. Several strategies have been developed to deliver exogenous macromolecules across cellular membranes.…”

“…Cell-penetrating peptides (CPPs) that can deliver therapeutic and diagnostic molecules into cells in a nontoxic manner have recently received considerable attention as a promising nonviral tool for the delivery of drugs and diagnostic agents [ 1 , 2 ]. The first CPP discovered, transactivator of transcription (Tat)-protein transduction domain (PTD), consists of eleven amino acids (YGRKKRRQRRR) of the HIV-1 Tat.…”

The Formation of Nanoparticles between Small Interfering RNA and Amphipathic Cell-Penetrating Peptides

“…Furthermore, the difference in stability to degradation may be caused by the particle properties. Transmission electron microscopy analysis showed that PF6/siRNA particles were tightly packed and almost perfectly spherical as are particles with NFs, but PF14 formed oval shaped particles with a larger surface area exposed to enzymes 40 . The stability of PFs to heparin displacement and serum has been compared to CPPs R9 and Tat, 41 and the results indicated that an optimal stability to heparin displacement and a high stability to serum could be crucial for higher delivery efficiency.…”

Screening and characterization of a novel high‐efficiency tumor‐homing cell‐penetrating peptide from the buffalo cathelicidin family

“…Cell‐penetrating peptides (CPPs) are short peptides composed of fewer than 30 amino acids that transport a variety of different bioactive molecules including peptides, proteins, nanoparticles, DNA, small interfering RNA, liposomes, and small molecule therapeutics into living cells. Most CPP sequences contain basic amino acid residues that are positively charged in a physiological environment to allow them to adhere to negatively charged cell membranes, and the hydrophobic residues of these CPPs interact with the lipid bilayer of the cell membrane, resulting in the cargo molecules carried by the CPP being transported into the cell by endocytosis .…”