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Nanostructured Biomaterials for Load-Bearing Applications
Published in Ashwani Kumar, Mangey Ram, Yogesh Kumar Singla, Advanced Materials for Biomechanical Applications, 2022
Nanostructured HA has been used so widely compared to its microscale or amorphous forms. It facilitates the bone regeneration process by improving the bone regeneration method’s cell attachment, proliferation and differentiation phases. Another nanomaterial that has received quality attention for biomedical applications is protein-based peptide amphiphiles (Pas). PA nanomaterials are self-assembled and very promising nanomaterials for tissue engineering applications. Nanostructured scaffolds formed using PA nanofibers exhibit outstanding cell proliferation, cell adhesion and bone generation properties due to the high surface area-to-volume ratio. The nanostructured scaffolds mimic the architecture of human tissue at the nanoscale level. The high surface area-to-volume ratio of the nanofibers, along with their microporous structure, favors cell adhesion, proliferation, migration and differentiation, all of which are highly desired properties for tissue engineering applications. Due to the high surface energy, cell adhesion and protein adsorption are positively affected in nanostructured biomaterials. Further, this factor helps the nanostructured biomaterials increase wound healing while decreasing the inflammatory response compared to the conventional biomaterials.
Self-Assembling Peptide Amphiphiles as a Versatile Future Nanomedicine Platform
Published in Shaker A. Mousa, Raj Bawa, Gerald F. Audette, The Road from Nanomedicine to Precision Medicine, 2020
Peptide amphiphiles (PAs) are composed of a hydrophobic portion and a hydrophilic portion. The sequences and chemical structures of PAs can be rationally designed to mediate self-assembled supramolecular structures for a broad range of applications [5, 17, 21]. The Stupp laboratory has developed many types of PAs that self-assemble into cylindrical structures, and demonstrated that each molecule of the nanofiber-forming PA could contain (1) a hydrophobic fatty acid segment (generally contains alkyl tails with 10 to 22 carbons) conjugated onto the N-terminus of the peptide segment via an amide bond; (2) a peptide segment that has a strong tendency to form β-sheet secondary structures via intermolecular hydrogen bonds; (3) a charged peptide segment with a series of charged amino acids to ensure the solubility while providing adequate spacing for any following bioactive functional segments; and (4) a functional segment that displays the bioactive peptide epitopes on the surface of the overall nanotube structure (Fig. 6.1) [1, 4, 5, 18, 21]. In addition to this “molecular template” for the design of cylindrical self-assembling PAs, in terms of some amphiphilic peptides that contain no fatty acid tail group, consecutive β-sheet-forming hydrophobic amino acid residues [22], π−π interactions of peptide chains containing aromatic rings [23], or ionic interactions between self-complimentary peptides with alternate cationic or anionic amino acid residues [24], can also trigger peptide self-assembly and direct the self-assembled structures into cylindrical shapes.
Self-Assembling Peptide Amphiphiles as a Versatile Future Nanomedicine Platform
Published in Shaker A. Mousa, Raj Bawa, Gerald F. Audette, The Road from Nanomedicine to Precision Medicine, 2019
Peptide amphiphiles (PAs) are composed of a hydrophobic portion and a hydrophilic portion. The sequences and chemical structures of PAs can be rationally designed to mediate self-assembled supramolecular structures for a broad range of applications [5, 17, 21]. The Stupp laboratory has developed many types of PAs that self-assemble into cylindrical structures, and demonstrated that each molecule of the nanofiber-forming PA could contain (1) a hydrophobic fatty acid segment (generally contains alkyl tails with 10 to 22 carbons) conjugated onto the N-terminus of the peptide segment via an amide bond; (2) a peptide segment that has a strong tendency to form β-sheet secondary structures via intermolecular hydrogen bonds; (3) a charged peptide segment with a series of charged amino acids to ensure the solubility while providing adequate spacing for any following bioactive functional segments; and (4) a functional segment that displays the bioactive peptide epitopes on the surface of the overall nanotube structure (Fig. 6.1) [1, 4, 5, 18, 21]. In addition to this “molecular template” for the design of cylindrical self-assembling PAs, in terms of some amphiphilic peptides that contain no fatty acid tail group, consecutive β-sheet-forming hydrophobic amino acid residues [22], π−π interactions of peptide chains containing aromatic rings [23], or ionic interactions between self-complimentary peptides with alternate cationic or anionic amino acid residues [24], can also trigger peptide self-assembly and direct the self-assembled structures into cylindrical shapes.
Design of peptide-PEG-Thiazole bound polypyrrole supramolecular assemblies for enhanced neuronal cell interactions
Published in Soft Materials, 2021
Sarah M. Broas, Ipsita A. Banerjee
Tissue Engineering (TE) seeks to provide an alternative to conventional treatments by aiming to repair and regenerate damaged tissue by optimal combination of the patient’s own cells with an appropriate biomaterial.[9] Early work has shown that despite the limited regenerative capacity of neurons, when provided with an appropriate environment, neurons can in fact exhibit axonal elongation and form networks.[10] The challenge, therefore, becomes developing a highly functional and biocompatible material capable of supporting neuronal tissue regeneration, that can mimic the highly specific, three-dimensional (3D) extracellular matrix (ECM).[11,12] While current research has shown some success in the usage of natural and synthetic biomaterials as neural tissue scaffolds, there remains a need for development of new biomaterials that can further enhance bioactivity and stimulate neural tissue regeneration. Materials derived from natural sources, such as fibronectin, [13,14] collagen, [15,16] fibrin, [17] alginate, [18] and agarose[19] are advantageous in that they inherently promote biological recognition, support cell adhesion and function, and are more biocompatible. However, they often lack the mechanical strength, tunability, and consistency. While synthetic materials, including poly (L-lactic acid) (PLA),[20,21] poly(ɛ-caprolactone),[22,23] and poly(lactic-co-glycolic acid) (PLGA),[24,25] can be designed to mimic elements of ECM, typically these polymers lack vast biological cues. Therefore, current research focuses on the development of hybrid biomaterials that integrate synthetic and natural components, in the quest to achieve synergistic benefits. For example, poly(3-hydroxybutyrate) (PHB) and poly (3-hydroxy butyrate-co-3-hydroxyvalerate) (PHBV) nanofibers have been combined with type I collagen to achieve proliferation and bi/multipolar morphology in Schwann cells.[26] Electrospun polyvinyl alcohol (PVA)/chitosan nanofibrous scaffolds have been shown to enhance viability and proliferation of PC12 nerve cells.[27] In other work, it was shown that electrospun serum albumin scaffolds doped with hemin and functionalized with recombinant proteins and growth factors supported attachment and differentiation of human-induced pluripotent stem cells (hiPSCs) and upon electrical stimulation resulted in branched neurites.[28] Self-assembling peptides and peptide amphiphiles are also attractive for tissue engineering scaffolds because of low-cost of production, and high bioactivity.[29] For example, RADA16 and RADA16-c(RGDfK) self-assembled peptides have been investigated as neural tissue engineering scaffolds.[30]