Design of 11-residue peptides with unusual biophysical properties: induced secondary structure in the absence of water

Use of Dynamic Shear Rheology to Understand Soy Protein Dispersion Properties

Soy flour dispersions are used as adhesives for bonding interior wood laminates, but the high viscosity of these dispersions requires low solids in the adhesive formulations; the greater water content causes excessive steam pressure during hot press manufacturing. This limits the utility of soy adhesives in replacing urea-formaldehyde adhesives; thus, understanding the cause of high soy viscosities is important. Lack of literature on aqueous soy flour dispersion rheology led to our dynamic rheology studies of these dispersions to understand high viscosity and the effect of various additives. Even at low soy solids, the elastic nature outweighs the viscous properties at low shear, although increasing the shear results in shear-thinning behavior after the yield point. At even higher shear, beyond the flow point where the storage and loss moduli cross, some of the dispersions show an additional shear thinning transition. The comparison of the rheological properties of aqueous dispersions of the soy flour and protein isolate, and another natural protein, ovalbumin from egg whites, led to a better understanding of different types of rheological behaviors. The experimental observations of two observed shear thinning events for soy are consistent with the model of dispersed particles, forming clusters that then form large scale flocculants.

Self-assembling peptide-based building blocks in medical applications

Peptides and peptide-conjugates, comprising natural and synthetic building blocks, are an increasingly popular class of biomaterials. Self-assembled nanostructures based on peptides and peptide-conjugates offer advantages such as precise selectivity and multifunctionality that can address challenges and limitations in the clinic. In this review article, we discuss recent developments in the design and self-assembly of various nanomaterials based on peptides and peptide-conjugates for medical applications, and categorize them into two themes based on the driving forces of molecular self-assembly. First, we present the self-assembled nanostructures driven by the supramolecular interactions between the peptides, with or without the presence of conjugates. The studies where nanoassembly is driven by the interactions between the conjugates of peptide-conjugates are then presented. Particular emphasis is given to in vivo studies focusing on therapeutics, diagnostics, immune modulation and regenerative medicine. Finally, challenges and future perspectives are presented.

A review of solute encapsulating nanoparticles used as delivery systems with emphasis on branched amphipathic peptide capsules

Various strategies are being developed to improve delivery and increase the biological half-lives of pharmacological agents. To address these issues, drug delivery technologies rely on different nano-sized molecules including: lipid vesicles, viral capsids and nano-particles. Peptides are a constituent of many of these nanomaterials and overcome some limitations associated with lipid-based or viral delivery systems, such as tune-ability, stability, specificity, inflammation, and antigenicity. This review focuses on the evolution of bio-based drug delivery nanomaterials that self-assemble forming vesicles/capsules. While lipid vesicles are preeminent among the structures; peptide-based constructs are emerging, in particular peptide bilayer delimited capsules. The novel biomaterial-Branched Amphiphilic Peptide Capsules (BAPCs) display many desirable properties. These nano-spheres are comprised of two branched peptides-bis(FLIVI)-K-KKKK and bis(FLIVIGSII)-K-KKKK, designed to mimic diacyl-phosphoglycerides in molecular architecture. They undergo supramolecular self-assembly and form solvent-filled, bilayer delineated capsules with sizes ranging from 20 nm to 2 μm depending on annealing temperatures and time. They are able to encapsulate different fluorescent dyes, therapeutic drugs, radionuclides and even small proteins. While sharing many properties with lipid vesicles, the BAPCs are much more robust. They have been analyzed for stability, size, cellular uptake and localization, intra-cellular retention and, bio-distribution both in culture and in vivo.

Peptide nanovesicles formed by the self-assembly of branched amphiphilic peptides

Peptide-based packaging systems show great potential as safer drug delivery systems. They overcome problems associated with lipid-based or viral delivery systems, vis-a-vis stability, specificity, inflammation, antigenicity, and tune-ability. Here, we describe a set of 15 & 23-residue branched, amphiphilic peptides that mimic phosphoglycerides in molecular architecture. These peptides undergo supramolecular self-assembly and form solvent-filled, bilayer delimited spheres with 50–200 nm diameters as confirmed by TEM, STEM and DLS. Whereas weak hydrophobic forces drive and sustain lipid bilayer assemblies, these all-peptide structures are stabilized potentially by both hydrophobic interactions and hydrogen bonds and remain intact at low micromolar concentrations and higher temperatures. A linear peptide lacking the branch point showed no self-assembly properties. We have observed that these peptide vesicles can trap fluorescent dye molecules within their interior and are taken up by N/N 1003A rabbit lens epithelial cells grown in culture. These assemblies are thus potential drug delivery systems that can overcome some of the key limitations of the current packaging systems.