Self-assembling Bioadhesive Inspired by the Fourth Repetitive Sequence of Balanus albicostatus Cement Protein 20 kDa (Balcp-20 k).

Barnacle cement proteins are multi-protein complexes composed of a series of functionally related synergistic proteins that enable barnacles to adhere strongly and consistently to various underwater substrates. There is no post-translational modification of barnacle cement proteins, which provides a possibility for the synthesis of similar adhesive materials. Balcp-20 k has four repetitive sequences with multiple conserved cysteine groups. Whether these repeats are separate functional units and the role of cysteine in adhesion is not clear. In order to investigate the adhesion properties of Balcp-20 k, we amplified and expressed R4 (DHLACNAKHPCWHKHCDCFC)4, which is a quadruple repeat of Balcp-20 k's fourth repetitive sequence, and S0R4 (DHLASNAKHPSWHKHSDSFS)4, all cysteine of R4 replaced by serine. Analysis showed that R4 had a similar structure to Balcp-20 k, and the amyloid fibrils structure formed by self-assembly of R4 played an important role in improving the adhesion strength. The absence of disulfide bonds in S0R4 prevents self-assembly, and the failure of self-assembly after the reduction of disulfide bonds of R4 by DTT indicates that disulfide bonds play an important role in self-assembly. With adhesion and coating analysis, it was found that R4 has good adhesion on different materials surfaces, which is better than Balcp-20 k, while S0R4 has weak adhesion, which is only better than BSA.

Synthesis of Surface-Enhanced Raman Scattering-Active Gold Nanoflowers by 5-Hydroxytryptophan in Acidic Solution.

We demonstrated a one-step synthesis of gold nanoflowers by 5-hydroxytryptophan (5-HTP) in acidic solutions at room temperature. The synthesized nanoflowers are 400 nm in dimension consisting of a solid core and many small petal-like nanoparticles (30-50 nm) in various directions. The shape, size and surface morphology of the gold nanostructure could be tuned by controlling the molar ratio of 5-HTP to HAuCl4 and HCl concentration. Examination of the nanoparticles at different reaction stages with transmission electron microscopy (TEM) reveals the shape evolutionary process of the nanoflowers to get a better understanding on their possible formation mechanism. Additionally, these gold nanoflowers exhibit a high SERS performance because of textured surface which is expected to provide many active sites.

Peptide derived from Pvfp-1 as bioadhesive on bio-inert surface.

Surface property is one important characteristic of materials, especially for ones that are bio-inert but designed for bio-medical application. In this study, we designed a series of peptides and compared their capacities as bioadhesive to improve the surface bioactivity of bio-inert material. The peptides were designed according to the sequence of Perna viridis foot protein 1 (Pvfp-1), one of the Mfp-1s (mussel foot protein 1) which play key roles in wet adhesion of mussel byssus. And the Teflon (PTFE) was chosen as a model of bio-inert material. With adsorption, adhesion and coating analysis, it was found that peptide C2 (M) (derived from the non-repeating region of Pvfp-1, contains modified DOPA) has superior coating and adhesion abilities especially on the bio-inert surface of PTFE. After coating with peptide C2 (M), the cell adhesion and spreading of osteoblast MC3T3-E1 cells on PTFE were significantly improved compared with those on non-coated surface, and the peptide-coating did not show any cell toxicity. Therefore, peptide C2 (M) is effective for improving the bioactivity of bio-inert PTFE, and could be potentially used as a bioadhesive on other bio-inert materials for biomedical application. Moreover, this study also provided new insights in designing other peptide-based bioadhesive materials.