1.Titanium Surface Priming with Phase-Transited Lysozyme to Establish a Silver Nanoparticle-Loaded Chitosan/Hyaluronic Acid Antibacterial Multilayer via Layer-by-Layer Self-Assembly.
Zhong X1, Song Y1, Yang P2, Wang Y1, Jiang S1, Zhang X1, Li C1. PLoS One. 2016 Jan 19;11(1):e0146957. doi: 10.1371/journal.pone.0146957. eCollection 2016.
OBJECTIVES: The formation of biofilm around implants, which is induced by immediate bacterial colonization after installation, is the primary cause of post-operation infection. Initial surface modification is usually required to incorporate antibacterial agents on titanium (Ti) surfaces to inhibit biofilm formation. However, simple and effective priming methods are still lacking for the development of an initial functional layer as a base for subsequent coatings on titanium surfaces. The purpose of our work was to establish a novel initial layer on Ti surfaces using phase-transited lysozyme (PTL), on which multilayer coatings can incorporate silver nanoparticles (AgNP) using chitosan (CS) and hyaluronic acid (HA) via a layer-by-layer (LbL) self-assembly technique.
2.Phospha-Michael Addition as a New Click Reaction for Protein Functionalization.
Lee YJ1, Kurra Y1, Liu WR2. Chembiochem. 2016 Mar 15;17(6):456-61. doi: 10.1002/cbic.201500697. Epub 2016 Feb 16.
A new type of click reaction between an alkyl phosphine and acrylamide was developed and applied for site-specific protein labeling in vitro and in live cells. Acrylamide is a small electrophilic olefin that readily undergoes phospha-Michael addition with an alkyl phosphine. Our kinetic study indicated a second-order rate constant of 0.07 m(-1) s(-1) for the reaction between tris(2-carboxyethyl)phosphine and acrylamide at pH 7.4. To demonstrate its application in protein functionalization, we used a dansyl-phosphine conjugate to successfully label proteins that were site-specifically installed with N(ɛ) -acryloyl-l-lysine and employed a biotin-phosphine conjugate to selectively probe human proteins that were metabolically labeled with N-acryloyl-galactosamine.
3.Novel bioadhesive polymers as intra-articular agents: Chondroitin sulfate-cysteine conjugates.
Suchaoin W1, Bonengel S1, Grießinger JA1, Pereira de Sousa I1, Hussain S2, Huck CW2, Bernkop-Schnürch A3. Eur J Pharm Biopharm. 2016 Apr;101:25-32. doi: 10.1016/j.ejpb.2016.01.006. Epub 2016 Jan 22.
The aim of this study was to generate and characterize a chondroitin sulfate-cysteine conjugate (CS-cys) as a novel bioadhesive agent for intra-articular use. Mucoadhesive properties of synthesized CS-cys were investigated by rheological measurement of polymer-mucus mixture and rotating cylinder method, while bioadhesive features of CS-cys on porcine articular cartilage were evaluated via tensile studies. Thiolation was achieved by attachment of l-cysteine to CS via amide bond formation mediated by carbodiimide as a coupling reagent. The conjugate exhibited 421.17±35.14μmol free thiol groups per gram polymer. The reduced CS-cys displayed 675.09±39.67μmol free thiol groups per gram polymer after disulfide bonds reduction using tris(2-carboxyethyl)phosphine hydrochloride. The increase in dynamic viscosity of thiolated CS due to oxidative disulfide bond formation was demonstrated using capillary viscometer. The combination of CS-cys and mucus led to 4.
4.Isolation and Analysis of Keratins and Keratin-Associated Proteins from Hair and Wool.
Deb-Choudhury S1, Plowman JE2, Harland DP2. Methods Enzymol. 2016;568:279-301. doi: 10.1016/bs.mie.2015.07.018. Epub 2015 Oct 24.
The presence of highly cross-linked protein networks in hair and wool makes them very difficult substrates for protein extraction, a prerequisite for further protein analysis and characterization. It is therefore imperative that these cross-links formed by disulfide bridges are first disrupted for the efficient extraction of proteins. Chaotropes such as urea are commonly used as efficient extractants. However, a combination of urea and thiourea not only improves recovery of proteins but also results in improved resolution of the keratins in 2DE gels. Reductants also play an important role in protein dissolution. Dithiothreitol effectively removes keratinous material from the cortex, whereas phosphines, like Tris(2-carboxyethyl)phosphine, remove material from the exocuticle. The relative extractability of the keratins and keratin-associated proteins is also dependent on the concentration of chaotropes, reductants, and pH, thus providing a means to preferentially extract these proteins.
