Branched Amphipathic Peptide Capsules: Different Ratios of the Two Constituent Peptides Direct Distinct Bilayer Structures, Sizes, and DNA Transfection Efficiency

Abstract

Branched amphipathic peptide capsules (BAPCs) are biologically derived, bilayer delimited, nanovesicles capable of being coated by or encapsulating a wide variety of solutes. The vesicles and their cargos are readily taken up by cells and become localized in the perinuclear region of cells. When BAPCs are mixed with DNA, the BAPCs act as cationic nucleation centers around which DNA winds. The BAPCs-DNA nanoparticles are capable of delivering plasmid DNA in vivo and in vitro yielding high transfection rates and minimal cytotoxicity. BAPCs share several biophysical properties with lipid vesicles. They are however considerably more stable-resisting disruption in the presence of chaotropes such as urea and guanidinium chloride, anionic detergents, proteases, and elevated temperature (∼95 °C). To date, all of our published results have utilized BAPCs that are composed of equimolar concentrations of the two branched sequences (Ac-FLIVI)-K-K-CO-NH and (Ac-FLIVIGSII)-K-K-CO-NH. The mixture of sizes was utilized to relieve potential curvature strain in the spherical capsule. In this article, different molar ratios of the two peptides were studied to test whether alternate ratios produced BAPCs with different biological and biophysical properties. Additionally, preparation (annealing) temperature was included as a second variable.

Delivery of lethal dsRNAs in insect diets by branched amphiphilic peptide capsules

“…For instance, they are water soluble, stable in blood and made entirely of natural amino acids 3 . They display sizes (depending on annealing conditions), ranging from 10-50 nm and are resistant to detergents, proteases and chaotropes 4,5,6 . The BAPCs used in this study are composed of an equimolar mixture of two branched peptides: bis(Ac-FLIVIGSII)-K-K 4 -CO-NH 2 and bis(Ac-FLIVI)-K-K 4 -CO-NH 2 and originate from the one of the pore-forming segments of human heart L-type dihydropyridine sensitive calcium channel 1 .…”

Insight Into Cellular Uptake and Transcytosis of Peptide Nanoparticles in a Generalist Caterpillar.

“…Biophysical Characterization of BAPC-dsRNA complexes BAPCs are formed by mixing the two peptides (Ac-FLIVI) 2 -K-K 4 -CO-NH 2 and (Ac-FLIVIGSII) 2 -K-K4-CO-NH2 at equimolar concentrations in water, which then co-assemble into 20-100 nm nanoparticles that are resistant to detergents, proteases, and chaotropes. 6,16 BAPCs have unusual but highly desirable properties for oral delivery of dsRNA in insects, such as side chains with pKa values between 9 to 13. 4 Nanoparticles with these functional groups are more stable in neutral and alkaline midgut environments of some species such as Spodoptera exigua, which is characterized for being recalcitrant to dsRNA effects 3 .…”

Potential Application of Silver Nanoparticles Encapsulated in Branched Amphiphilic Peptide Capsules to Circumvent Antibiotic Resistance in Methicillin-Resistant Staphylococcus Aureus: A Research Protocol

“…AgNP encapsulation is planned to occur during natural BAPC self-assembly. Bis(FLIVI)-K-KKKK and bis(FLIVIGSII)-K-KKKK represent the two branched polymers which form the capsule, and will be dissolved in neat 2,2,2-Trifluoroethanol to achieve a fixed final calculation of 0.1 mM [25]. In this solvent, the polymers are helical and facilitate BAPC formation.…”