Molecules

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14 pages, 2595 KiB

Open AccessArticle

Thiol-ene Reaction: An Efficient Tool to Design Lipophilic Polyphosphoesters for Drug Delivery Systems

by Stéphanie Vanslambrouck, Raphaël Riva, Bernard Ucakar, Véronique Préat, Mick Gagliardi, Daniel G. M. Molin, Philippe Lecomte and Christine Jérôme

Molecules 2021, 26(6), 1750; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26061750 - 20 Mar 2021

Cited by 9 | Viewed by 2870

Abstract

Poly(ethylene glycol)-b-polyphosphoester (PEG-b-PPE) block copolymer nanoparticles are promising carriers for poorly water soluble drugs. To enhance the drug loading capacity and efficiency of such micelles, a strategy was investigated for increasing the lipophilicity of the PPE block of these [...] Read more.

Poly(ethylene glycol)-b-polyphosphoester (PEG-b-PPE) block copolymer nanoparticles are promising carriers for poorly water soluble drugs. To enhance the drug loading capacity and efficiency of such micelles, a strategy was investigated for increasing the lipophilicity of the PPE block of these PEG-b-PPE amphiphilic copolymers. A PEG-b-PPE copolymer bearing pendant vinyl groups along the PPE block was synthesized and then modified by thiol-ene click reaction with thiols bearing either a long linear alkyl chain (dodecyl) or a tocopherol moiety. Ketoconazole was used as model for hydrophobic drugs. Comparison of the drug loading with PEG-b-PPE bearing shorter pendant groups is reported evidencing the key role of the structure of the pendant group on the PPE backbone. Finally, a first evidence of the biocompatibility of these novel PEG-b-PPE copolymers was achieved by performing cytotoxicity tests. The PEG-b-PPE derived by tocopherol was evidenced as particularly promising as delivery system of poorly water-soluble drugs. Full article

(This article belongs to the Special Issue Phosphorus-Containing Materials and Polymers: How a Central Element of All Living Matter can be Used in the Synthetic World)

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13 pages, 4430 KiB

Open AccessArticle

Modulation of Macrophage Polarization by Phospholipids on the Surface of Titanium

by Hongxuan Quan, Yongjoon Kim, Lele Wu, Hee-Chul Park and Hyeong-Cheol Yang

Molecules 2020, 25(11), 2700; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25112700 - 10 Jun 2020

Cited by 9 | Viewed by 3316

Abstract

Macrophage polarization has become increasingly important for the improvement of the biocompatibility of biomaterials. In this study, we coated Ti discs with phospholipids (phosphatidylserine/phosphatidylcholine [4:1 mole/mole]) by evaporating the solvent under vacuum, and observed the polarization of RAW 264.7 cells cultured on the [...] Read more.

Macrophage polarization has become increasingly important for the improvement of the biocompatibility of biomaterials. In this study, we coated Ti discs with phospholipids (phosphatidylserine/phosphatidylcholine [4:1 mole/mole]) by evaporating the solvent under vacuum, and observed the polarization of RAW 264.7 cells cultured on the discs. The coated discs were hydrated before cell culture was added. The shape of the hydrated phospholipids varied with the concentration of loaded phospholipids: a perforated layer (0.1 mM), tubules and spheres (1 mM), and spheres (10 mM). RAW 264.7 cells exhibited different morphologies, depending on the concentration of phospholipids. On the coated discs, the gene expression and protein release of TGF-β1, VEGF, Arg-1, and TNF-α were downregulated, especially with 10 mM phospholipids. The stimulation of mRNA expression and the protein release of those genes by IL-4 and LPS were also disturbed on the phospholipid-coated discs. In conclusion, the polarization of RAW 264.7 cells was prevented by hydrated phospholipids on Ti discs. Full article

(This article belongs to the Special Issue Phosphorus-Containing Materials and Polymers: How a Central Element of All Living Matter can be Used in the Synthetic World)

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17 pages, 7978 KiB

Open AccessArticle

Self-Healing Properties of Bioinspired Amorphous CaCO₃/Polyphosphate-Supplemented Cement

by Emad Tolba, Shunfeng Wang, Xiaohong Wang, Meik Neufurth, Maximilian Ackermann, Rafael Muñoz-Espí, Bothaina M. Abd El-Hady, Heinz C. Schröder and Werner E. G. Müller

Molecules 2020, 25(10), 2360; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25102360 - 19 May 2020

Cited by 8 | Viewed by 3541

Abstract

There is a strong interest in cement additives that are able to prevent or mitigate the adverse effects of cracks in concrete that cause corrosion of the reinforcement. Inorganic polyphosphate (polyP), a natural polymer that is synthesized by bacteria, even those on cement/concrete, [...] Read more.

There is a strong interest in cement additives that are able to prevent or mitigate the adverse effects of cracks in concrete that cause corrosion of the reinforcement. Inorganic polyphosphate (polyP), a natural polymer that is synthesized by bacteria, even those on cement/concrete, can increase the resistance of concrete to progressive damage from micro-cracking. Here we use a novel bioinspired strategy based on polyP-stabilized amorphous calcium carbonate (ACC) to give this material self-healing properties. Portland cement was supplemented with ACC nanoparticles which were stabilized with 10% (w/w) Na–polyP. Embedding these particles in the hydrated cement resulted in the formation of calcite crystals after a hardening time of 10 days, which were not seen in controls, indicating that the particles dissolve and then transform into calcite. While there was no significant repair in the controls without ACC, almost complete closure of the cracks was observed after a 10 days healing period in the ACC-supplemented samples. Nanoindentation measurements on the self-healed crack surfaces showed a similar or slightly higher elasticity at a lower hardness compared to non-cracked surfaces. Our results demonstrate that bioinspired approaches, like the use of polyP-stabilized ACC shown here, can significantly improve the repair capacity of Portland cement. Full article

(This article belongs to the Special Issue Phosphorus-Containing Materials and Polymers: How a Central Element of All Living Matter can be Used in the Synthetic World)

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16 pages, 1828 KiB

Open AccessArticle

Polydopamine-Lysophosphatidate-Functionalised Titanium: A Novel Hybrid Surface Finish for Bone Regenerative Applications

by Fiona Baldwin, Tim J. Craig, Anna I. Shiel, Timothy Cox, Kyueui Lee and Jason P. Mansell

Molecules 2020, 25(7), 1583; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25071583 - 30 Mar 2020

Cited by 7 | Viewed by 2496

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Phosphorus-Containing Materials and Polymers: How a Central Element of All Living Matter can be Used in the Synthetic World)

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15 pages, 2492 KiB

Open AccessArticle

Aromatic vs. Aliphatic Hyperbranched Polyphosphoesters as Flame Retardants in Epoxy Resins

by Jens C. Markwart, Alexander Battig, Maria M. Velencoso, Dennis Pollok, Bernhard Schartel and Frederik R. Wurm

Molecules 2019, 24(21), 3901; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules24213901 - 29 Oct 2019

Cited by 19 | Viewed by 5784

Abstract

The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, [...] Read more.

The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs. Full article

(This article belongs to the Special Issue Phosphorus-Containing Materials and Polymers: How a Central Element of All Living Matter can be Used in the Synthetic World)

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Review

Jump to: Research

37 pages, 9088 KiB

Open AccessReview

Opening up the Toolbox: Synthesis and Mechanisms of Phosphoramidates

by Emeka J. Itumoh, Shailja Data and Erin M. Leitao

Molecules 2020, 25(16), 3684; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25163684 - 13 Aug 2020

Cited by 16 | Viewed by 6318

Abstract

This review covers the main synthetic routes to and the corresponding mechanisms of phosphoramidate formation. The synthetic routes can be separated into six categories: salt elimination, oxidative cross-coupling, azide, reduction, hydrophosphinylation, and phosphoramidate-aldehyde-dienophile (PAD). Examples of some important compounds synthesized through these routes [...] Read more.

This review covers the main synthetic routes to and the corresponding mechanisms of phosphoramidate formation. The synthetic routes can be separated into six categories: salt elimination, oxidative cross-coupling, azide, reduction, hydrophosphinylation, and phosphoramidate-aldehyde-dienophile (PAD). Examples of some important compounds synthesized through these routes are provided. As an important class of organophosphorus compounds, the applications of phosphoramidate compounds, are also briefly introduced. Full article

(This article belongs to the Special Issue Phosphorus-Containing Materials and Polymers: How a Central Element of All Living Matter can be Used in the Synthetic World)

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45 pages, 18735 KiB

Open AccessReview

Main-Chain Phosphorus-Containing Polymers for Therapeutic Applications

by Paul Strasser and Ian Teasdale

Molecules 2020, 25(7), 1716; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25071716 - 08 Apr 2020

Cited by 36 | Viewed by 4956

Abstract

Polymers in which phosphorus is an integral part of the main chain, including polyphosphazenes and polyphosphoesters, have been widely investigated in recent years for their potential in a number of therapeutic applications. Phosphorus, as the central feature of these polymers, endears the chemical [...] Read more.

Polymers in which phosphorus is an integral part of the main chain, including polyphosphazenes and polyphosphoesters, have been widely investigated in recent years for their potential in a number of therapeutic applications. Phosphorus, as the central feature of these polymers, endears the chemical functionalization, and in some cases (bio)degradability, to facilitate their use in such therapeutic formulations. Recent advances in the synthetic polymer chemistry have allowed for controlled synthesis methods in order to prepare the complex macromolecular structures required, alongside the control and reproducibility desired for such medical applications. While the main polymer families described herein, polyphosphazenes and polyphosphoesters and their analogues, as well as phosphorus-based dendrimers, have hitherto predominantly been investigated in isolation from one another, this review aims to highlight and bring together some of this research. In doing so, the focus is placed on the essential, and often mutual, design features and structure–property relationships that allow the preparation of such functional materials. The first part of the review details the relevant features of phosphorus-containing polymers in respect to their use in therapeutic applications, while the second part highlights some recent and innovative applications, offering insights into the most state-of-the-art research on phosphorus-based polymers in a therapeutic context. Full article

(This article belongs to the Special Issue Phosphorus-Containing Materials and Polymers: How a Central Element of All Living Matter can be Used in the Synthetic World)

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10 pages, 2605 KiB

Open AccessReview

Bone Mineral Affinity of Polyphosphodiesters

by Yasuhiko Iwasaki

Molecules 2020, 25(3), 758; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25030758 - 10 Feb 2020

Cited by 15 | Viewed by 3769

Abstract

Biomimetic molecular design is a promising approach for generating functional biomaterials such as cell membrane mimetic blood-compatible surfaces, mussel-inspired bioadhesives, and calcium phosphate cements for bone regeneration. Polyphosphoesters (PPEs) are candidate biomimetic polymer biomaterials that are of interest due to their biocompatibility, biodegradability, [...] Read more.

Biomimetic molecular design is a promising approach for generating functional biomaterials such as cell membrane mimetic blood-compatible surfaces, mussel-inspired bioadhesives, and calcium phosphate cements for bone regeneration. Polyphosphoesters (PPEs) are candidate biomimetic polymer biomaterials that are of interest due to their biocompatibility, biodegradability, and structural similarity to nucleic acids. While studies on the synthesis of PPEs began in the 1970s, the scope of their use as biomaterials has increased in the last 20 years. One advantageous property of PPEs is their molecular diversity due to the presence of multivalent phosphorus in their backbones, which allows their physicochemical and biointerfacial properties to be easily controlled to produce the desired molecular platforms for functional biomaterials. Polyphosphodiesters (PPDEs) are analogs of PPEs that have recently attracted interest due to their strong affinity for biominerals. This review describes the fundamental properties of PPDEs and recent research in the field of macromolecular bone therapeutics. Full article

(This article belongs to the Special Issue Phosphorus-Containing Materials and Polymers: How a Central Element of All Living Matter can be Used in the Synthetic World)

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