Matrix metalloproteinase-triggered self-assembling peptides for biomedical applications.

MMP-13 Plays a Role in Keratinocyte Migration, Angiogenesis, and Contraction in Mouse Skin Wound Healing

Self-assembled peptide and protein nanostructures for anti-cancer therapy: Targeted delivery, stimuli-responsive devices and immunotherapy.

We report the molecular self-assembly of two amphiphilic peptides (A6K and V6K) and the application of their self-assemblies as organic templates to direct biosilica formation. Under ambient conditions, A6K self-assembled into nanotubes 2.7 nm tall and approximately 1 μm to 2 μm long. In contrast, V6K self-assembled into lamellar-stack nanostructures approximately 4 nm tall and under 100 nm long. The self-assembled peptide nanostructures were used as organic templates to direct biosilica formation. Comparing with the self-assembled structures formed by the peptide/anions system, novel silica morphologies can be obtained by changing the peptide composition, using different anions, and applying electrostatic/flow fields. We observed that the presence of anions is important but not enough to produce ordered silica structures with novel morphologies. This study provides further understanding of silica biomineralization tailored by assembled peptides, which offers a simple but efficient method to control the formation of inorganic material.

We developed novel activatable probe using self-assembled peptide nanowires with low affinity and toxicity to tumor cells in the absence of matrix metalloproteinase that showed activated high affinity and toxicity and provided a highly selective and efficient platform for targeted therapy and tumor imaging.

The advancement of diverse electrochemistry technologies depends on the development of novel proton conducting polymers. Inspired by the efficacy of proton transport through proteins, we show in this work that self-assembling peptide nanostructures may be a promising alternative for such organic proton conducting materials. We demonstrate that aromatic amino acids, which participate in charge transport in nature, unprecedentedly promote proton conduction under both high and low relative humidity conditions for d,l α-cyclic peptide nanotubes. For dehydrated networks long-range order of the assemblies, induced by the aromatic side chains, is shown to be a dominating factor for promoting conductivity. However, for hydrated networks this order of effect is less significant and conductivity can be improved by the introduction of proton donating carboxylic acid peptide side chains in addition to the aromatic side chains despite the lower order of the assemblies. Based on these observations, a novel cyclic peptide that incorporates non-natural naphthyl side chains was designed. Self-assembled nanotubes of this peptide show greatly improved dehydrated conductivity, while maintaining high conductivity under hydrated conditions. We envision that the demonstrated modularity and versatility of these bio inspired nanostructures will make them extremely attractive building blocks for the fabrication of devices for energy conversion and storage applications, as well as other applications that involve proton transport, whether dry or wet conductivity is desired.

In nature, biological nanomaterials are synthesized under ambient conditions in a natural microscopic-sized laboratory, such as a cell. Biological molecules, such as peptides and proteins, undergo self-assembly processes in vivo and in vitro, and these monomers are assembled into various nanometer-scale structures at room temperature and atmospheric pressure. The self-assembled peptide nanostructures can be further organized to form nanowires, nanotubes, and nanoparticles via their molecular-recognition functions. The application of molecular self-assemblies of synthetic peptides as nanometer-scale building blocks in devices is robust, practical, and affordable due to their advantages of reproducibility, large-scale production ability, monodispersity, and simpler experimental methods. It is also beneficial that smart functionalities can be added at desired positions in peptide nanotubes through well-established chemical and peptide syntheses. These features of peptide-based nanotubes are the driving force for investigating and developing peptide nanotube assemblies for biological and non-biological applications.

Protein nanowires exhibiting specific biological activities hold promise for interacting with living cells and controlling and predicting biological responses such as apoptosis, endocytosis, and cell adhesion. In this chapter, fabrication of various size-controlled protein nanowires by single-particle nanofabrication technique (SPNT) is reviewed. The human serum albumin (HSA) nanowires of various lengths can be fabricated, from HSA nanodots to HSA nanowires with extremely high aspect ratios of over 1000, by controlling the thickness of the film. The diameters of the protein nanowires are almost equal to the diameter of self-assembled protein and peptide nanostructures. Degradation of the HSA nanowires was examined using protease. The biotinylated human serum albumin nanowires can be transformed into nanowires exhibiting a biological function such as an enzyme through using avidin–biotin interaction. Interestingly, 2D Protein sheets and protein synthetic polymer nanowires can be fabricated by the application of SPNT. SPNT is a versatile platform for functionalizing the surface of any protein molecule with an extremely large surface area.

Nowadays, peptide based disease prevention is an important topic in biomedical science, which may radically change the traditional use of biomaterials and improve the life quality. Self-assembled nanostructured peptides have been receiving extreme attention in the drug delivery field due their high biocompatibility levels, better loading capacity, extended circulation and localization in required target site. This article focuses on the composition and synthesis of different forms of self-assembled peptide nanostructures as nanotubes, nanofibers, nanoparticles, nanotapes and nanogels. The most important properties for their self assembled mechanism and their biomedical applications are also discussed. Various potential applications of nanostructures peptide could be developed designed for therapeutic agent's delivery, biosensors, anticancerous and antimicrobial activities.

Effects of external force fields on peptide self-assembly and biomimetic silica synthesis

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that play important roles in physiological and pathological conditions. Both gelatinases (MMP-2 and -9) and membrane-type 1 MMP (MMP-14) are important targets for inhibition, since their roles in various diseases, including cancer, have been well established. We describe herein a set of mechanism-based inhibitors that show high selectivity to gelatinases and MMP-14 (inhibitor 3) and to only MMP-2 (inhibitors 5 and 7). These molecules bind to the active sites of these enzymes, initiating a slow binding profile for the onset of inhibition, which leads to covalent enzyme modification. The full kinetic analysis for the inhibitors is reported. These are nanomolar inhibitors (Ki) for the formation of the noncovalent enzyme-inhibitor complexes. The onset of slow binding inhibition is rapid (k(on) of 10(2) to 10(4) M(-1) s(-1) and the reversal of the process is slow (k(off) of 10(-3) to 10(-4) s(-1)). However, with the onset of covalent chemistry with the best of these inhibitors (e.g. inhibitor 3), very little recovery of activity (<10%) was seen over 48 h of dialysis. We previously reported that broad spectrum MMP inhibitors like GM6001 enhance MT1-MMP-dependent activation of pro-MMP-2 in the presence of tissue inhibitor of metalloproteinases-2. Herein, we show that inhibitor 3, in contrast to GM6001, had no effect on pro-MMP-2 activation by MT1-MMP. Furthermore, inhibitor 3 reduced tumor cell migration and invasion in vitro. These results show that these new inhibitors are promising candidates for selective inhibition of MMPs in animal models of relevant human diseases.

Inducible Nitric Oxide Synthase Deficiency Impairs Matrix Metalloproteinase-9 Activity and Disrupts Leukocyte Migration in Hepatic Ischemia/Reperfusion Injury

Essential amino acids in catalytic sites of native enzymes are important in nature inspired catalyst designs. Active sites of enzymes contain the coordinated assembly of multiple amino acids, and catalytic action is generated by the dynamic interactions among multiple residues. However, catalysis studies are limited by the complex and dynamic structure of the enzyme; and it is difficult to exclusively attribute a given function to a specific residue. Minimalistic approaches involving artificial catalytic sites are promising for the investigation of the enzyme function in the absence of non-essential protein components, and self-assembling peptide nanostructures are especially advantageous in this context. Here we demonstrate the design and characterization of an enzyme-mimetic catalytic nanosystem presenting essential residues (Ser, His, Asp). The function of each residue and its combinations on the nanostructures in hydrolysis reaction was studied. The catalytic self-assembled nanostructures were used for efficient ester hydrolysis such as a model substrate (pNPA) and a natural substrate (acetylcholine) highlighting the key role of self-assembly in catalytic domain formation to test the efficiency of the de novo designed catalyst as a catalytic triad model.

Over the past three decades, numerous studies have shown a strong connection between matrix metalloproteinase 9 (MMP-9) levels and myocardial infarction (MI) mortality and left ventricle remodeling and dysfunction. Despite this fact, clinical trials using MMP-9 inhibitors have been disappointing. This review focuses on the roles of MMP-9 in MI wound healing. Infiltrating leukocytes, cardiomyocytes, fibroblasts, and endothelial cells secrete MMP-9 during all phases of cardiac repair. MMP-9 both exacerbates the inflammatory response and aids in inflammation resolution by stimulating the pro-inflammatory to reparative cell transition. In addition, MMP-9 has a dual effect on neovascularization and prevents an overly stiff scar. Here, we review the complex role of MMP-9 in cardiac wound healing, and highlight the importance of targeting MMP-9 only for its detrimental actions. Therefore, delineating signaling pathways downstream of MMP-9 is critical.

Wearable sensors for real-time physiological monitoring based on self-assembled diphenylalanine peptide nanostructures

Self-assembled peptide nanostructures have been increasingly exploited as functional materials for applications in biomedicine and energy. The emergent properties of these nanomaterials determine the applications for which they can be exploited. It has recently been appreciated that nanomaterials composed of multicomponent coassembled peptides often display unique emergent properties that have the potential to dramatically expand the functional utility of peptide-based materials. This review presents recent efforts in the development of multicomponent peptide assemblies. The discussion includes multicomponent assemblies derived from short low molecular weight peptides, peptide amphiphiles, coiled coil peptides, collagen, and β-sheet peptides. The design, structure, emergent properties, and applications for these multicomponent assemblies are presented in order to illustrate the potential of these formulations as sophisticated next-generation bio-inspired materials.