Facile Surface Functionalization with Glycosaminoglycans by Direct Coating with Mussel Adhesive Protein

Molecular docking study on europium nanoparticles and mussel adhesive protein for effective detection of latent fingerprints

Background: Reflecting on the difficulty of finding the evidence of latent fingerprints on wet and rough surfaces, scientists need to visualise those fingermarks without any background interference and stable adhesion of visualising material over the fingermark residues.Objective: To stabilize the interaction with the fingermarks, the synthesized nanoparticles were conjugated with a highly adhesive biopolymer, Mussel Adhesive Protein (MAP) which can effectively interact with fingerprint deposits.Material and Methods: Rare earth metal, europium oxide and nanoparticles were used as a visualisation material to get high contrast and reduced background interference-based fingerprints. To stabilise the interaction with the fingermarks, the synthesised nanoparticles were conjugated with highly adhesive biopolymer, Mussel Adhesive Protein (MAP) which can effectively interacts with fingerprint deposits. A molecular docking study was done using Auto-Dock to find the binding affinity between the metal nanoparticle and the protein. Further, the stability of the bioconjugated with fingerprint residues was analysed by protein-protein interaction study through patch dock and PDB Sum.Results: The docking analysis between europium and nanoparticles with MAP was found to be -8.77 kcal/mol and -47.49 kcal/mol respectively. Protein-protein interaction studies showed a highest affinity for dermcidin and keratin with a binding affinity of -16.76 kcal/mol and -24.76 kcal/mol respectively.Conclusions: The docking studies showed an efficient interaction between the synthesised molecules and the fingermark residues. Results of these interaction studies proved that this bio-conjugated complex can be explored for efficient visualisation of low intensified fingermarks.

Diatom-Inspired Silica Nanostructure Coatings with Controllable Microroughness Using an Engineered Mussel Protein Glue to Accelerate Bone Growth on Titanium-Based Implants

Silica nanoparticles (SiNPs) have been utilized to construct bioactive nanostructures comprising surface topographic features and bioactivity that enhances the activity of bone cells onto titanium-based implants. However, there have been no previous attempts to create microrough surfaces based on SiNP nanostructures even though microroughness is established as a characteristic that provides beneficial effects in improving the biomechanical interlocking of titanium implants. Herein, a protein-based SiNP coating is proposed as an osteopromotive surface functionalization approach to create microroughness on titanium implant surfaces. A bioengineered recombinant mussel adhesive protein fused with a silica-precipitating R5 peptide (R5-MAP) enables direct control of the microroughness of the surface through the multilayer assembly of SiNP nanostructures under mild conditions. The assembled SiNP nanostructure significantly enhances the in vitro osteogenic cellular behaviors of preosteoblasts in a roughness-dependent manner and promotes the in vivo bone tissue formation on a titanium implant within a calvarial defect site. Thus, the R5-MAP-based SiNP nanostructure assembly could be practically applied to accelerate bone-tissue growth to improve the stability and prolong the lifetime of medical implantable devices.

Natural healing-inspired collagen-targeting surgical protein glue for accelerated scarless skin regeneration

Skin scarring after deep dermal injuries is a major clinical problem due to the current therapies limited to established scars with poor understanding of healing mechanisms. From investigation of aberrations within the extracellular matrix involved in pathophysiologic scarring, it was revealed that one of the main factors responsible for impaired healing is abnormal collagen reorganization. Here, inspired by the fundamental roles of decorin, a collagen-targeting proteoglycan, in collagen remodeling, we created a scar-preventive collagen-targeting glue consisting of a newly designed collagen-binding mussel adhesive protein and a specific glycosaminoglycan. The collagen-targeting glue specifically bound to type I collagen in a dose-dependent manner and regulated the rate and the degree of fibrillogenesis. In a rat skin excisional model, the collagen-targeting glue successfully accelerated initial wound regeneration as defined by effective reepithelialization, neovascularization, and rapid collagen synthesis. Moreover, the improved dermal collagen architecture was demonstrated by uniform size of collagen fibrils, their regular packing, and a restoration of healthy tissue component. Collectively, our natural healing-inspired collagen-targeting glue may be a promising therapeutic option for improving the healing rate with high-quality and effective scar inhibition.

Adding Functions to Biomaterial Surfaces through Protein Incorporation

The concept of biomaterials has evolved from one of inert mechanical supports with a long-term, biologically inactive role in the body into complex matrices that exhibit selective cell binding, promote proliferation and matrix production, and may ultimately become replaced by newly generated tissues in vivo. Functionalization of material surfaces with biomolecules is critical to their ability to evade immunorecognition, interact productively with surrounding tissues and extracellular matrix, and avoid bacterial colonization. Antibody molecules and their derived fragments are commonly immobilized on materials to mediate coating with specific cell types in fields such as stent endothelialization and drug delivery. The incorporation of growth factors into biomaterials has found application in promoting and accelerating bone formation in osteogenerative and related applications. Peptides and extracellular matrix proteins can impart biomolecule- and cell-specificities to materials while antimicrobial peptides have found roles in preventing biofilm formation on devices and implants. In this progress report, we detail developments in the use of diverse proteins and peptides to modify the surfaces of hard biomaterials in vivo and in vitro. Chemical approaches to immobilizing active biomolecules are presented, as well as platform technologies for isolation or generation of natural or synthetic molecules suitable for biomaterial functionalization.

Surface modification of titanium with curcumin: a promising strategy to combat fibrous encapsulation

Fibrous encapsulation that prevents the direct contact between an implant and the bone can cause implant failure. However, prevention of fibrous encapsulation is difficult because of the lack of effective strategies which can selectively control the growth of fibroblasts and osteoblasts. Because curcumin, an extract from Curcuma longa, was recently found to reduce the formation of fibrous tissue, it is hypothesized that loading curcumin on implant surfaces would be efficacious in inhibiting fibrous encapsulation without adversely affecting the osteoblast functions. To prove this hypothesis, curcumin was loaded on to a titanium surface using poly(dopamine) as an anchor, and the behaviors of fibroblasts and osteoblasts on these curcumin-modified surfaces were investigated. Curcumin was successfully loaded on to titanium and showed a low release after incubation in phosphate-buffered saline for seven days. On the curcumin-modified surfaces, fibroblast proliferation was suppressed, and fibrous marker expressions as well as collagen synthesis were significantly reduced. These reductions were possibly because of the enhancement of fibroblast apoptosis induced by the surface curcumin. In contrast, no significant reduction in osteoblast functions was observed on the curcumin-modified substrates. These findings may provide a promising solution to reduce fibrous encapsulation, and thus may be highly beneficial for orthopaedic applications.