There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

The desired mechanical and biological performances of collagen that have led to its broad application as a building block in the biomedical field attributed to its intrinsic hierarchical structure from the nanoscale to macroscale, are discussed herein. Modulating the self-assembly process using regulatory factors can lead to obtaining collagenous materials with tuneable functional performance, which can then determine distinctive cellular responses. Herein, we present an overview of the corresponding characterization techniques used to detect the changes in light transmittance, architecture and mechanics during collagen fibrillogenesis. By combining regulatory parameters with characterization methods, researchers can selectively fabricate collagenous biomaterials with various functional responses.

Self-assembly of collagen-based biomaterials: preparation, characterizations and biomedical applications

A UV-cured nanofibrous membrane of vinylbenzylated gelatin-poly(ɛ-caprolactone) dimethacrylate co-network by scalable free surface electrospinning.

Supramolecular-based nanofibers.

Antimicrobial biomaterials are critical to aid in the regeneration of oral soft tissue and prevent or treat localised bacterial infections. With the rising trend in antibiotic resistance, there is a pressing clinical need for new antimicrobial chemistries and biomaterial design approaches enabling on-demand activation of antibiotic-free antimicrobial functionality following an infection that are environment-friendly, flexible and commercially-viable. This study explores the feasibility of integrating a bioresorbable electrospun polymer scaffold with localised antimicrobial photodynamic therapy (aPDT) capability. To enable aPDT, we encapsulated a photosensitiser (PS) in polyester fibres in the PS inert state, so that the antibacterial function would be activated on-demand via a visible light source. Fibrous scaffolds were successfully electrospun from FDA-approved polyesters, either poly(epsilon-caprolactone (PCL) or poly[(rac-lactide)-co-glycolide] (PLGA) with encapsulated PS (either methylene blue (MB) or erythrosin B (ER)). The electrospun fibres achieved an ~100 wt.% loading efficiency of PS, which significantly increased their tensile modulus and reduced their average fibre diameter and pore size with respect to PS-free controls. In vitro, PS release varied between a burst release profile to limited release within 100 hours depending on the selected scaffold formulation. Exposure of PS-encapsulated PCL fibres to visible light successfully led to at least a 1 log reduction in E. coli viability after 60 minutes of light exposure whereas PS-free electrospun controls did not inactive microbes. This study successfully demonstrates the significant potential of PS-encapsulated electrospun fibres as photodynamically active biomaterial for antibiotic-free infection control.

/pdf/photodynamically-active-electrospun-fibres-for-antibiotic-4irqt13inh.pdf

Photodynamically Active Electrospun Fibres for Antibiotic-Free Infection Control.

Self-assembling peptides (SAPs) have been shown to offer great promise in therapeutics and have the ability to undergo self-assembly and form ordered nanostructures. However SAP gels are often associated with inherent weak and transient mechanical properties and incorporation of them into polymeric matrices is a route to enhance their mechanical stability. The aim of this work was to incorporate P11-8 peptide (CH3COQQRFOWOFEQQNH2) within poly(e-caprolactone) (PCL) fibrous webs via one-step electrospinning, aiming to establish the underlying relationships between spinning process, molecular peptide conformation, and material internal architecture. Electrospinning of PCL solutions (6% w/w) in hexafluoro-2-propanol (HFIP) containing up to 40 mg mL−1 P11-8 resulted in the formation of fibres in both nano- (10–100 nm) and submicron range (100–700 nm), in contrast to PCL only webs, which displayed a predominantly submicron fibre distribution. FTIR and CD spectroscopy on both PCL/peptide solutions and resulting electrospun webs revealed monomeric and β-sheet secondary conformation, respectively, suggesting the occurrence of peptide self-assembly during electrospinning due to solvent evaporation. The peptide concentration (0 → 40 mg mL−1) was found to primarily affect the internal structure of the fabric at the nano-scale, whilst water as well as cell culture medium contact angles were dramatically decreased. Nearly no cytotoxic response (>90% cell viability) was observed when L929 mouse fibroblasts were cultured in contact with electrospun peptide loaded samples. This novel nanofibrous architecture may be the basis for an interesting material platform for e.g. hard tissue repair, in light of the presence of the self-assembled P11-8 in the PCL fibrous structure.

/pdf/a-structurally-self-assembled-peptide-nano-architecture-by-3awjz9ynoy.pdf

A structurally self-assembled peptide nano-architecture by one-step electrospinning

Self-assembling peptides (SAPs) have shown to offer great promise in therapeutics and have the ability to undergo self-assembly and form ordered nanostructures. However SAP gels are often associated with inherent weak and transient mechanical properties and incorporation of them into polymeric matrices is a route to enhance their mechanical stability. The aim of this work was to incorporate P11-8 peptide (CH3COQQRFOWOFEQQNH2) within poly(epsilon-caprolactone) (PCL) fibrous webs via one-step electrospinning, aiming to establish the underlying relationships between spinning process, molecular peptide conformation, and material internal architecture. Electrospinning of PCL solutions (6% w/w) in hexafluoro-2-propanol (HFIP) containing up to 40 mg/ml P11-8 resulted in the formation of fibres in both nano- (10-100 nm) and submicron range (100-700 nm), in contrast to PCL only webs, which displayed a predominantly submicron fibre distribution. FTIR and CD spectroscopy on both PCL/peptide solutions and resulting electrospun webs revealed monomeric and beta-sheet secondary conformation, respectively, suggesting the occurrence of peptide self-assembly during electrospinning due to solvent evaporation. The peptide concentration (0 -> 40 mg/ml) was found to primarily affect the internal structure of the fabric at the nano-scale, whilst water as well as cell culture medium contact angles were dramatically decreased. Nearly no cytotoxic response (> 90% cell viability) was observed when L929 mouse fibroblasts were cultured in contact with electrospun peptide loaded samples. This novel nanofibrous architecture may be the basis for an interesting material platform for e.g. hard tissue repair, in light of the presence of the self assembled P11-8 in the PCL fibrous structure.

/pdf/a-structurally-self-assembled-peptide-nano-architecture-by-4gspv3eln1.pdf

Reem Alazragi

Papers

A structurally self-assembled peptide nano-architecture by one-step electrospinning

A Structurally Self-Assembled Peptide Nano-Architecture by One-Step Electrospinning