18 research outputs found
Polydopamine-lysophosphatidate-functionalised titanium: A novel hybrid surface finish for bone regenerative applications
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Aseptic loosening of total joint replacements (TJRs) continues to be the main cause of implant failures. The socioeconomic impact of surgical revisions is hugely significant; in the United Kingdom alone, it is estimated that £135m is spent annually on revision arthroplasties. Enhancing the longevity of titanium implants will help reduce the incidence and overall cost of failed devices. In realising the development of a superior titanium (Ti) technology, we took inspiration from the growing interest in reactive polydopamine thin films for biomaterial surface functionalisations. Adopting a “one-pot” approach, we exposed medical-grade titanium to a mildly alkaline solution of dopamine hydrochloride (DHC) supplemented with (3S)1-fluoro-3-hydroxy-4-(oleoyloxy)butyl-1-phosphonate (FHBP), a phosphatase-resistant analogue of lysophosphatidic acid (LPA). Importantly, LPA and selected LPA analogues like FHBP synergistically cooperate with calcitriol to promote human osteoblast formation and maturation. Herein, we provide evidence that simply immersing Ti in aqueous solutions of DHC-FHBP afforded a surface that was superior to FHBP-Ti at enhancing osteoblast maturation. The facile step we have taken to modify Ti and the biological performance of the final surface finish are appealing properties that may attract the attention of implant manufacturers in the future
Surface design for immobilization of an antimicrobial peptide mimic for efficient anti‐biofouling
Microbial surface attachment negatively impacts a wide range of devices from water purification membranes to biomedical implants. Mimics of antimicrobial peptides (AMPs) constituted from poly(N‐substituted glycine) "peptoids" are of great interest as they resist proteolysis and can inhibit a wide spectrum of microbes. We investigate how terminal modification of a peptoid AMP‐mimic and its surface immobilization affect antimicrobial activity. We also demonstrate a convenient surface modification scheme for enabling alkyne‐azide "click" coupling on amino‐functionalized surfaces. Our results verified that the N‐ and C‐terminal peptoid structures are not required for antimicrobial activity. Moreover, our peptoid immobilization density and choice of PEG tether resulted in a "volumetric" spatial separation between AMPs that, compared to past studies, enabled the highest AMP surface activity relative to bacterial attachment. Our analysis suggests the importance of spatial flexibility for membrane activity and that AMP separation may be a controlling parameter for optimizing surface anti‐biofouling
Systematic Approach to Mimic Phenolic Natural Polymers for Biofabrication
In nature, phenolic biopolymers are utilized as functional tools and molecular crosslinkers to control the mechanical properties of biomaterials. Of particular interest are phenolic proteins/polysaccharides from living organisms, which are rich in catechol and/or gallol groups. Their strong underwater adhesion is attributed to the representative phenolic molecule, catechol, which stimulates intermolecular and intramolecular crosslinking induced by oxidative polymerization. Significant efforts have been made to understand the underlying chemistries, and researchers have developed functional biomaterials by mimicking the systems. Owing to their unique biocompatibility and ability to transform their mechanical properties, phenolic polymers have revolutionized biotechnologies. In this review, we highlight the bottom-up approaches for mimicking polyphenolic materials in nature and recent advances in related biomedical applications. We expect that this review will contribute to the rational design and synthesis of polyphenolic functional biomaterials and facilitate the production of related applications
Repetitive Bacterial Disinfection of Respirators by Polydopamine Coating
To solve the current and future mask shortage problems, developing methods of disinfecting respirators is essential, where none of the existing methods have been successfully utilized until recently. Herein, we introduce a novel method of conferring antibacterial activity to the main filtering material (i.e., polypropylene (PP)) of a respirator through sequential polydopamine (PDA) coatings. Two-step dip-coating in dopamine solution, which corresponds to one complete cycle, produces stable PDA films at the interface of the filtering material, which subsequently locally generates H2O2 that can be further transformed into hydroxyl radicals to inactivate pathogens. Specifically, the primary dip-coating creates a scaffold PDA film that acts as a mechanical support, and anchoring dopamine, which substantially produces H2O2, is immobilized to the scaffold PDA during the subsequent secondary dip-coating process. The antibacterial activity was confirmed by bacterial tests using Escherichia coli. In short, the number of colonies after incubation of the polypropylene filter with and without the PDA coating in the bacterial solution was compared. The number of bacteria in the PDA-coated sample (0.54 × 109 CFU/mL·cm2) was significantly reduced compared to that in the original PP sample (0.81 × 109 CFU/mL·cm2), demonstrating a positive relationship with the H2O2 production. Moreover, this antibacterial ability can be maintained by simply utilizing additional PDA coatings, suggesting that the respirators can be recycled. Finally, the in vitro cytotoxicity was confirmed by the CCK-8 assay, which demonstrated that the PDA-coated PP filter is biocompatible. We believe that the newly proposed method for disinfection of respirators may substitute conventional methods and can be used to alleviate the mask shortage problem
Crosslinking Mechanisms of Phenol, Catechol, and Gallol for Synthetic Polyphenols: A Comparative Review
Since the first introduction of a synthetic polyphenol called polydopamine, both it and its derivatives have received significant attention from material scientists owing to their unique functionality. In particular, synthetic polyphenols have been utilized as interfacial engineering tools; many important review papers have been published regarding this topic. However, despite those that have focused on the applicability of synthetic polyphenols, fundamental aspects of crosslinking mechanisms and resultant characteristics have still been overlooked in the community. This review covers the mechanisms for building synthetic polyphenols, which are dependent on the number of hydroxyl groups of each phenolic building block. The inherent physicochemical properties of the developed polyphenolic materials are discussed in depth herein. This review can provide guidelines for selecting appropriate phenolic building blocks when designing relevant polyphenolic biomaterials
Crosslinking Mechanisms of Phenol, Catechol, and Gallol for Synthetic Polyphenols: A Comparative Review
Since the first introduction of a synthetic polyphenol called polydopamine, both it and its derivatives have received significant attention from material scientists owing to their unique functionality. In particular, synthetic polyphenols have been utilized as interfacial engineering tools; many important review papers have been published regarding this topic. However, despite those that have focused on the applicability of synthetic polyphenols, fundamental aspects of crosslinking mechanisms and resultant characteristics have still been overlooked in the community. This review covers the mechanisms for building synthetic polyphenols, which are dependent on the number of hydroxyl groups of each phenolic building block. The inherent physicochemical properties of the developed polyphenolic materials are discussed in depth herein. This review can provide guidelines for selecting appropriate phenolic building blocks when designing relevant polyphenolic biomaterials
Supporting Information Reversible Tissue Sticker Inspired by Chemistry in Plant-Pathogen Relationship
11 pages. -- Materials and methods: 1.1 Molecular weight determined by gel permeation chromatography. -- 1.2 Film bursting tests by monitoring pressure given on the GMTA film. -- 1.3 An in vitro degradation profile of GMTA films in fetal bovine serum. -- 1.4 Cytotoxicity tests by agar diffusion methods. -- 1.5 Subcutaneous implantation and histology staining. -- Figures S1-S7. -- Movie S1. TA spray curing on an uncured GM film showing enhanced interfacial adhesion on a freshly prepared porcine heart.Peer reviewe