Trimethylene Carbonate Research Articles

Determination of the Individual Block Lengths of the Block Copolymers of Poly(trimethylene carbonate) by Liquid Chromatography at Critical Conditions

Determination of the Individual Block Lengths of the Block Copolymers of Poly(trimethylene carbonate) by Liquid Chromatography at Critical Conditions

Biomimicking Covalent Organic Frameworks Nanocomposite Coating for Integrated Enhanced Anticorrosion and Antifouling Properties of a Biodegradable Magnesium Stent

The utilization of biodegradable magnesium (Mg) alloys in the fabrication of temporary non-vascular stents is an innovative trend in biomedical engineering. However, the heterogeneous degradation profiles of these biomaterials, together with potential bacterial colonization that could precipitate infectious or stenotic complications, are critical obstacles precluding their widespread clinical application. In pursuit of overcoming these limitations, this study applies the principles of biomimicry, particularly the hydrophobic and anti-fouling characteristics of lotus leaves, to pioneer the creation of nanocomposite coatings. These coatings integrate poly-trimethylene carbonate (PTMC) with covalent organic frameworks (COFs), constituting a multiscale crosslinked network that modifies the stent's surface microstructure. The strategic design of the coating's topography, porosity, and self-polishing capabilities collectively aims to decelerate degradation processes and minimize biological adhesion. The protective qualities of the coatings were substantiated through rigorous testing in both in vitro dynamic bile tests and in vivo New Zealand rabbit choledochal models. Empirical findings from these trials confirmed that the implementation of COF-based nanocomposite coatings robustly fortifies Mg implantations, conferring heightened resistance to both biocorrosion and biofouling as well as improved biocompatibility within bodily environments. The outcomes of this research elucidate a comprehensive framework for the multifaceted strategies against stent corrosion and fouling, thereby charting a visionary pathway toward the systematic conception of a new class of reliable COF-derived surface modifications poised to amplify the efficacy of Mg-based stents. Statement of SignificanceBiodegradable magnesium (Mg) alloys are widely utilized in temporary stents, though their rapid degradation and susceptibility to bacterial infection pose significant challenges. Our research has developed a nanocomposite coating inspired by the lotus, integrating poly-trimethylene carbonate with covalent organic frameworks (COF). The coating achieved self-polishing property and optimal surface energy on the Mg substrate, which decelerates stent degradation and reduces biofilm formation. Comprehensive evaluations utilizing dynamic bile simulations and implantation in New Zealand rabbit choledochal models reveal that the coating improves the durability and longevity of the stent. The implications of these findings suggest the potential COF-based Mg alloy stent surface treatments and a leap forward in advancing stent performance and endurance in clinical applications.

Use of Biomaterials in 3D Printing as a Solution to Microbial Infections in Arthroplasty and Osseous Reconstruction.

The incidence of microbial infections in orthopedic prosthetic surgeries is a perennial problem that increases morbidity and mortality, representing one of the major complications of such medical interventions. The emergence of novel technologies, especially 3D printing, represents a promising avenue of development for reducing the risk of such eventualities. There are already a host of biomaterials, suitable for 3D printing, that are being tested for antimicrobial properties when they are coated with bioactive compounds, such as antibiotics, or combined with hydrogels with antimicrobial and antioxidant properties, such as chitosan and metal nanoparticles, among others. The materials discussed in the context of this paper comprise beta-tricalcium phosphate (β-TCP), biphasic calcium phosphate (BCP), hydroxyapatite, lithium disilicate glass, polyetheretherketone (PEEK), poly(propylene fumarate) (PPF), poly(trimethylene carbonate) (PTMC), and zirconia. While the recent research results are promising, further development is required to address the increasing antibiotic resistance exhibited by several common pathogens, the potential for fungal infections, and the potential toxicity of some metal nanoparticles. Other solutions, like the incorporation of phytochemicals, should also be explored. Incorporating artificial intelligence (AI) in the development of certain orthopedic implants and the potential use of AI against bacterial infections might represent viable solutions to these problems. Finally, there are some legal considerations associated with the use of biomaterials and the widespread use of 3D printing, which must be taken into account.

Effect of trimethylene carbonate segments on the structure and properties of poly(L‐lactide‐glycolide‐trimethylene carbonate) terpolymers for biodegradable vascular stents

AbstractThe total biodegradable vascular stent made of poly(L‐lactide‐glycolide‐trimethylene carbonate) terpolymers with excellent performances has the potential to be used in a new generation of medical implant devices. In this work, the properties and structure of terpolymers were investigated, which were found to be controlled by the composition of the copolymer chain. The amorphous trimethylene carbonate segments not only disturbed the sequence regularity of the L‐lactide segment, but also reduced the crystallization ability of the material. Furthermore, it is the flexible segments in the terpolymer chains that improve the plastic flow capacity, increase the flexibility of chains as well as reduce the apparent activation energy of thermal degradation of materials. Such a chain structured terpolymer exhibited good extrudability and buildability in 3D printing and formed a vascular stent with a cohesion entanglement characteristic microstructure during the process. The crush resistance with radially applied load and crush resistance with parallel plates of stent were 2561.4 mm Hg and 0.24 N/mm, respectively.

Opposite Mechanical Preference of Bone/Nerve Regeneration in 3D-Printed Bioelastomeric Scaffolds/Conduits Consistently Correlated with YAP-Mediated Stem Cell Osteo/Neuro-Genesis.

To systematically unveil how substrate stiffness, a critical factor in directing cell fate through mechanotransduction, correlates with tissue regeneration, novel biodegradable and photo-curable poly(trimethylene carbonate) fumarates (PTMCFs) for fabricating elastomeric 2D substrates and 3D bone scaffolds/nerve conduits, are presented. These substrates and structures with adjustable stiffness serve as a unique platform to evaluate how this mechanical cue affects the fate of human umbilical cord mesenchymal stem cells (hMSCs) and hard/soft tissue regeneration in rat femur bone defect and sciatic nerve transection models; whilst, decoupling from topographical and chemical cues. In addition to a positive relationship between substrate stiffness (tensile modulus: 90-990kPa) and hMSC adhesion, spreading, and proliferation mediated through Yes-associated protein (YAP), opposite mechanical preference is revealed in the osteogenesis and neurogenesis of hMSCs as they are significantly enhanced on the stiff and compliant substrates, respectively. In vivo tissue regeneration demonstrates the same trend: bone regeneration prefers the stiffer scaffolds; while, nerve regeneration prefers the more compliant conduits. Whole-transcriptome analysis further shows that upregulation of Rho GTPase activity and the downstream genes in the compliant group promote nerve repair, providing critical insight into the design strategies of biomaterials for stem cell regulation and hard/soft tissue regeneration through mechanotransduction.

Hydrolyzable and biocompatible aliphatic polycarbonates with ether-functionalized side chains attached via amide linkers

Investigating polymer degradation mechanisms enables the establishment of controlled degradation techniques for the development of sustainable and recyclable materials. Hydration can play a crucial role in controlling the hydrolysis of polymers. Here, ether-functionalized aliphatic polycarbonates (APCs) susceptible to nonenzymatic hydrolysis were developed for application as biocompatible biomaterials. Among these polymers, those grafted with 2-methoxyethyl and 3-methoxypropyl side chains via an amide group were highly wettable, strongly interacted with water, and experienced almost complete hydrolysis in phosphate-buffered saline over 30 days, which was attributed to the hydrogen bonding between water and the amide/methoxy groups. In an alkaline medium, all amide-linked APCs were completely hydrolyzed within 30 days, regardless of the side-chain structure. In contrast, the nonamide-linked APCs and a representative aliphatic polycarbonate, poly(trimethylene carbonate), were minimally degraded in the buffer and experienced <31% degradation under alkaline conditions. The APC with the 3-methoxypropyl side chain exhibited platelet adhesion properties comparable to those of ether-functionalized APCs previously reported as blood-compatible polymers. Thus, our results demonstrate the effects of an amide linker on the hydration and hydrolytic properties of APCs and can help establish new design concepts for degradable polymers.

Strength of small-bites abdominal wall closure using different suturing methods and materials in an experimental animal model.

Using small instead of large bites for laparotomy closure results in lower incidence of incisional hernia, but no consensus exists on which suture material to use. This study aimed to compare five different closure strategies in a standardized experimental setting. Fifty porcine abdominal walls were arranged into 5 groups: (A) running 2/0 polydioxanone; (B) interlocking 2/0 polydioxanone; (C) running size 0 barbed polydioxanone; (D) running size 0 barbed glycolic acid and trimethylene carbonate; (E) running size 0 suturable polypropylene mesh. The small-bites technique was used for linea alba closure in all. The abdominal walls were divided into a supra- and infra-umbilical half, resulting in 20 specimens per group that were pulled apart in a tensile testing machine. Maximum tensile force and types of suture failure were registered. The highest tensile force was measured when using barbed polydioxanone (334.8N ± 157.0), but differencesdid not reach statisticalsignificance. Infra-umbilical abdominal walls endured a significantly higher maximum tensile force compared to supra-umbilical (397N vs 271N, p < 0.001). Barbed glycolic acid and trimethylene carbonate failed significantly more often (25% vs 0%, p = 0.008). Based on tensile force, both interlocking and running suture techniques using polydioxanone, and running sutures using barbed polydioxanone or suturable mesh, seem to be suitable for abdominal wall closure. Tensile strength was significantly higher in infra-umbilical abdominal walls compared to supra-umbilical. Barbed glycolic acid and trimethylene carbonate should probably be discouraged for fascial closure, because of increased risk of suture failure.

In situ forming, mechanically resilient hydrogels prepared from 4a-[PEG-b-PTMC-Ac] and thiolated chondroitin sulfate for nucleus pulposus cell delivery.

Intervertebral disk degeneration (IVDD) is a common condition that causes severe back pain and affects patients' mobility and life quality considerably. IVDD originates within the central region of the disk called the nucleus pulposus (NP). Removing the damaged tissue and replacing it with NP cells (NPCs) delivered within an in situ forming hydrogel is a promising treatment approach. Herein we describe a hydrogel formulation based on 4-arm [poly(ethylene glycol)-b-poly(trimethylene carbonate)-acrylate] (4a[PEG-b-PTMC-Ac]) crosslinked with thiolated chondroitin sulfate via Michael-type reaction for this purpose. A library of hydrogels based on 15 kDa 4a-[PEG] with PTMC blocks of varying molecular weight were prepared and characterized. The instantaneous moduli of the hydrogels were adjustable from 24 to 150 kPa depending on the length of the PTMC block and the polymer volume fraction. The influence of each of these parameters was effectively explained using both scaling or mean field theories of polyelectrolyte hydrogels. The hydrogels were resistant to cyclic compressive loading and degraded gradually over 70 days in vitro. A hydrogel formulation with an instantaneous modulus at the high end of the range of values reported for human NP tissue was chosen to assess the ability of these hydrogels for delivering NPCs. The prepolymer solution was injectable and formed a hydrogel within 30 minutes at 37 °C. Bovine NPCs were encapsulated within this hydrogel with high viability and proliferated throughout a 28 day, hypoxic culture period. The encapsulated NPCs formed clusters and deposited collagen type II but no collagen type I within the hydrogels. Despite an initial gradual decrease, a steady-state modulus was reached at the end of the 28 day culture period that was within the range reported for healthy human NP tissue. This in situ forming hydrogel formulation is a promising approach and with further development could be a viable clinical treatment for IVDD.

Enhancing the corrosion resistance of magnesium alloys with biodegradable poly(trimethylene carbonate) chemical modification coating

Magnesium (Mg) alloys have great potential as biodegradable materials for medical device. However, their susceptibility to corrosion poses a significant challenge for practical applications. In this study, the poly(trimethylene carbonate)-dimethacrylate (PTMC-dMA) was employed as a coating material for ZE21B magnesium alloys. Upon UV irradiation, the PTMC-dMA macromer undergoes cross-linking to form a uniform PTMC coating with a thickness of approximately 5 μm, effectively protecting the magnesium alloy. The corrosion resistance in simulated body fluid (SBF) was evaluated through immersion testing, which showed minimal hydrogen generation (0.16 mL/cm2) during the initial 24-h period and slight corrosion observed on the PTMC-coated magnesium alloy surface after continuous immersion for 21 days. The silane coupling agent significantly enhanced the adhesive performance between the polymer and alloy. Micro-scratch tests revealed adhesion forces of 3.79 N and 5.75 N for coatings without and with the silane agent, respectively. Electrochemical tests also demonstrated the efficacy of silane treatment, showing corrosion currents of 2.100 × 108 A/cm2 for silane-treated samples compared 6.263 × 107 A/cm2 for untreated ones. Given its exceptional tensile and protective properties, this coated material is ideal for intricate bioresorbable applications, like endovascular bioresorbable stents.

Exploring the Efficiency of Lithium Stripping/Plating in Solid Polymer Anode-Free Lithium Cells

Traditional Li-ion batteries (LIBs) are widely used in various electronic devices due to their advantages in energy storage applications. However, finding ways to push the energy densities even higher would be highly desirable for the further rapid development of electric vehicles and electromobility. Li metal batteries and anode-free batteries (AFBs) – where the Li metal is plated in situ from Li+ ions taken from the cathode – have received extensive attention and research due to their very high specific capacity.[1] However, Li ions are unevenly deposited on the surface of anodes to form Li dendrite during the charging and discharging process, which severely deteriorates their electrochemical performance and battery safety.[2] To solve this problem, many researchers choose solid polymer electrolytes (SPEs) instead of liquid electrolytes in the batteries, because of the stability of SPEs towards Li metal.Long-term cycling of AFBs requires high-efficiency Li metal stripping and plating, which in a solid polymer cell is highly dependent on the polymer electrolyte system used, so finding appropriate host materials and salts to for the SPEs is very necessary. Poly(ethylene oxide) (PEO)-based SPEs are one of the most popular host materials for SPEs, due to their excellent chemical stability. Poly(ε-caprolactone) (PCL)-based SPEs have higher ionic conductivity and can be cycled at room temperature.[3] Poly(trimethylene carbonate) (PTMC)-based SPEs have high lithium transference number and better mechanical properties.[4] Lithium bis(trifluoromethanesulphonyl)imide (LiTFSI) is one of the most popular salts used for SPEs. Recently, lithium difluoro(oxalate)borate (LiDFOB) and lithium bis(oxalato)borate (LiBOB) have been considered a promising alternative as electrolyte because they can passivate electrode surfaces and protect electrode materials.[5] Combinations of these materials are all potentially relvant for application in AFBs.In this work, three different polymer host materials, PEO, PTMC, and PCL, were explored as polymer electrolytes together with LiTFSI salt for their performance in anode-less cell setups, testing the plating/striping coulombic efficiency (CE) in Cu || Li cells. The results reveal clear issues for the CE of cycling in the PEO:LiTFSI system, while low-concentration PTMC:LiTFSI instead shows much more promising results. Changing the LiTFSI salt for LiBOB or LiDFOB also improves the CE of the cells.[1] Beyene, T. T., Jote, B. A., Wondimkun, Z. T., Olbassa, B. W., Huang, C. J., Thirumalraj, B., Wang C. H., Su W. N., Dai H., Hwang B. J., Effects of concentrated salt and resting protocol on solid electrolyte interface formation for improved cycle stability of anode-free lithium metal batteries, ACS applied materials & interfaces, 2019, 11(35), 31962.[2] Huang W. Z., Zhao C. Z., Wu P., Yuan H., Feng W. E., Liu Z. Y., Lu Y., Sun S., Fu Z. H., Hu J. K., Yang S. J., Anode‐Free Solid‐State Lithium Batteries: A Review, Advanced Energy Materials, 2022, 12(26), 2201044.[3] Chiu, C. Y., Chen, H. W., Kuo, S. W., Huang, C. F., Chang, F. C., Investigating the effect of miscibility on the ionic conductivity of LiClO4/PEO/PCL ternary blends. Macromolecules, 2004, 37(22), 8424.[4] Li Z., Mogensen R., Mindemark J., Bowden T., Brandell D., Tominaga Y., Ion‐conductive and thermal properties of a synergistic poly (ethylene carbonate)/poly (trimethylene carbonate) blend electrolyte. Macromolecular rapid communications, 2018, 39(14):1800146.[5] Shkrob, I. A., Zhu, Y., Marin, T. W., Abraham, D. P., Mechanistic Insight into the Protective Action of Bis (oxalato) borate and Difluoro (oxalate) borate Anions in Li-Ion Batteries, The Journal of Physical Chemistry C, 2013, 117(45), 23750.

Ionic Transport in Solid Poly(trimethylene carbonate)-Li6.7Al0.3La3Zr2O12 Composite Electrolytes

Speeding up solid-state batteries commercialization requires deeper understanding of fundamentals behind the ionic transport mechanism in solid electrolytes. PEO has been widely investigated as a polymer host for both polymer and composite electrolytes. Nevertheless, there has been several confusions about its conduction mechanism being dependent on different factors. One crucial factor is the ceramic filler, garnet-type Li6.7Al0.3La3Zr2O12 "LLZO" has been considered as the most favorable ceramic material to be used for composite electrolytes thanks to its high ionic conductivity and electrochemical stability. For this work, a fully-amorphous polycarbonate-based poly(trimethylene carbonate) "PTMC" is chosen to investigate the ionic transport in a composite system composed of PTMC:LiTFSI as a polymer matrix with LLZO as an active ceramic filler according to both "ceramic-in-polymer" and "polymer-in-ceramic" approaches. The study focuses on understanding Li+-conduction depending on two properties: The ceramic particle loading and the LLZO surface chemistry. The study outputs suggest that there is an interplay between the surface chemistry and the particles loading controlling the Li-ion transport. Figure 1

Role of Copper as Current Collectors in the Reductive Reactivity of Polymers for Anode-Free Lithium Metal Batteries - Insights from DFT and AIMD Studies

Understanding the role of current collectors (CCs) in the reductive reactivity of polymers on Li metal and the resultant solid electrolyte interphase (SEI) formation is essential for improving the performance of anode-free lithium metal batteries (AFLMBs). In this study, we have examined the reactivity of three polymeric hosts: poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly(trimethylene carbonate) (PTMC) at Li metal supported on Cu surfaces (Li/Cu) using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. In particular, the effect of copper (Cu) CCs on polymer stability, electronic structure, and their reduction reactions is investigated and compared to that of pure Li (100) surface. Through time-dependent Bader charge transfer analysis, electron transfer is identified as the triggering factor for polymer reduction. Based on the simulations, we find that the Cu CCs have a significant influence on the charge distribution of the Li metals, which increases electron transfer to the polymers and thereby accelerates polymers reduction. This thereby leads to different reaction mechanisms as compared to on Li-metal. The findings suggest that utilization of Cu CCs avoid production of CO molecules and improves the quality of the formed SEI layer. Figure 1

A Step Towards the Impossible – the Combination of High Ionic Conductivity and Mechanical Stability in Highly Crystalline Solid Polyketone Electrolytes

Implementation of solid polymer electrolytes (SPEs) is believed to be one pathway forward in the development of lithium-metal batteries (LMBs) that are both safe and possesses high capacities. This combination is possible since the free-standing SPE maintains its mechanical integrity during electrochemical and thermal exposure while utilizing lithium metal as the negative electrode, thus accessing the extremely high theoretical capacity of lithium metal. The main drawback for SPEs are however the poor ionic conductivity compared to the liquid electrolytes used in lithium-ion batteries today.[1] The low ionic conductivity for SPEs stems from the conduction mechanism of the ions, which is a slower process in SPEs compared to in liquid electrolytes. In general, the conductivity in SPEs are confined to the amorphous regions, where segmental motion of the polymer chains facilitates the ion transport; while the crystalline regions restrict the movements of the polymer chains and impairs the ion transport.[2] The highly crystalline polyketone poly(1-oxoheptamethylene) (POHM) is a material that has shown interesting characteristics for implementation as a SPE in batteries. In earlier studies, the polyketone revealed an extensive improvement of the ionic conductivity upon increasing the salt concentration, although the crystallinity remained with a high melting point.[3] Herein this study, the effect of the crystallinity on the characteristics and the performance was investigated further. To understand its effect, a second less hydrogenated version of POHM was synthesized, POHM-75, which is fully amorphous at high salt concentrations. The characteristics of the polyketones were in addition also compared with the more well-studied SPEs, that is polyethylene oxide (PEO) and poly(trimethylene carbonate) (PTMC). Focus of the presentation is on the interplay between the ionic conductivity and mechanical stability for the polyketones, for which something different to the normally observed tradeoff between the two properties is observed. The electrochemical performance of the polyketones are furthermore evaluated when implemented as SPEs in LMBs at extreme temperature environments, a possible application area for mechanically stable SPEs.[1] D. Zhou, D. Shanmukaraj, A. Tkacheva, M. Armand, G. Wang, Chem 2019, 5, 2326-2352.[2] M. A. Ratner, P. Johansson, D. F. Shriver, MRS Bulletin 2011, 25, 31-37.[3] T. Eriksson, H. Gudla, Y. Manabe, T. Yoneda, D. Friesen, C. Zhang, Y. Inokuma, D. Brandell, J. Mindemark, Macromolecules 2022, 55, 10940-10949. Figure 1

Poly(L-co-D,L-lactic acid-co-trimethylene carbonate) for extrusion-based 3D printing: Comprehensive characterization and cytocompatibility assessment

Extrusion-based 3D printing is a well-established material processing technique that has shown promise in employing a variety of polymers. Poly(lactic acid) is the most studied and widely used raw material in 3D printing, which can be modified by copolymerization with trimethylene carbonate (TMC), for tissue engineering applications. In this study, the aim was to explore the characterization of Poly(L-co-D,L-lactic acid-co-trimethylene carbonate) (PLDLA-TMC) at different ratios (60/40, 70/30, 80/20, and 90/10), focusing on their physicochemical, thermal, and rheological characterization, as well as their cytocompatibility. The results demonstrated shear-thinning behavior and highlighted the influence of TMC content on viscoelastic properties. The printing speed of 4 mm s−1 allowed the obtaining of scaffolds with rectangular pores and controlling of extrusion temperature promoted the formation of uniform filaments with high print quality. Additionally, the cytocompatibility assessment of the scaffolds revealed the terpolymer's potential for tissue engineering across a wide range of applications.

Preparation, characterization, and in vitro/vivo evaluation of a multifunctional electrode coating for cochlear implants

Cochlear implantation (CI) is the primary intervention for patients with sensorineural hearing loss to restore their hearing. However, approximately 90 % of CI recipients experience unexpected fibrosis around the inserted electrode arrays due to acute and chronic inflammation. This fibrosis leads to progressive residual hearing loss. Addressing this complication is crucial for enhancing CI outcomes, yet an effective treatment has not yet been found. In this study, we developed a multifunctional dexamethasone (DXM)-loaded polytrimethylene carbonate (PTMC) electrode coating to mitigate inflammatory reactions and fibrosis after CI. This thin and flexible coating could preserve the mechanical performance of the electrode and reduce the implantation resistance for CI. The in vitro release studies demonstrated the DXM-PTMC coating's efficient drug loading and sustained release capability over 90 days. DXM-PTMC also showed long-term stability, high biocompatibility, and effective anti-inflammatory effects in vitro and in vivo. Compared with the uncoated group, DXM-PTMC coating significantly inhibited the expression of inflammatory factors, such as NO, TNF-α, IL-1β, and IL-6. DXM-PTMC coating suppressed fibrosis in rat implantation models for 3 weeks by reducing both acute and chronic inflammation. Our findings suggest that DXM-PTMC coating is a novel strategy to improve the outcomes of CI.

Investigation of the mechanical properties and degradation of ester-free poly(trimethylene carbonate) derivatives bearing various bulky aromatic groups

Investigation of the mechanical properties and degradation of ester-free poly(trimethylene carbonate) derivatives bearing various bulky aromatic groups

In Vitro and In Vivo Degradation of Photo-Crosslinked Poly(Trimethylene Carbonate-co-ε-Caprolactone) Networks.

Three-armed poly(trimethylene carbonate) (PTMC) and poly(trimethylene carbonate-co-Ɛ-caprolactone) (P(TMC-co-ε-CL)) macromers with molecular weights of approximately 30kgmol-1 are synthesized by ring-opening polymerization and subsequent functionalization with methacrylic anhydride. Networks are then prepared by photo-crosslinking. To investigate the in vitro and in vivo degradation properties of these photo-crosslinked networks and assess the effect of ε-caprolactone content on the degradation properties, PTMC networks, and copolymer networks with two different TMC:ε-CL ratios are prepared. PTMC networks degraded slowly, via an enzymatic surface erosion process, both in vitro and in vivo. Networks prepared from P(TMC-co-ε-CL) macromers with a 74:26 ratio are found to degrade slowly as well, via a surface erosion process, albeit at a higher rate compared to PTMC networks. Increasing the ε-CL content to a ratio of 52:48, resulted in a faster degradation. These networks lost their mechanical properties much sooner than the other networks. Thus, PTMC and P(TMC-co-ε-CL) networks are interesting networks for tissue engineering purposes and the exact degradation properties can be tuned by varying the TMC:ε-CL ratio, providing researchers with a tool to obtain copolymer networks with the desired degradation rate depending on the intended application.

Lewis-pair derived activated lactone initiator (ALI) complex for rapid, controlled, bench stable and selective ring-opening polymerization of (macro)lactones

Selective, active, stable, and general catalysts for the controlled ring-opening polymerization of (macro)lactones are central in our pursuit of a more benign material economy. Within, we explore the formation of an activated lactone initiator (ALI) based on ZnEt2-1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an air-stable and selective initiator/catalyst, yielding linear polymers with one ß-keto ester and one alcohol end-group. Ring-opening polymerization (ROP) with high activity and control was found for unsubstituted (macro)lactones (ω-pentadecalactone (PDL), hexadecanolide (HDL), δ-valerolactone (δVL), and ε-caprolactone (εCL)) and cyclic carbonate trimethylene carbonate (TMC). A particular focus was placed on studying the ALI for the polymerization of strainless PDL and strained εCL. In contrast, ALI-ROP could not polymerize lactones containing substituents on the terminal carbon, indicative of the coordination insertion features of the polymerization. This work explores selective catalysts with high control, fast kinetics, and superb air stability towards the next generation of greener materials.

A novel self-gripping long-term resorbable mesh providing temporary support for open primary ventral and incisional hernia

A novel synthetic fully long-term resorbable self-gripping mesh has been recently developed to reinforce soft tissue where weakness exists during ventral hernia repair open procedures. This resorbable mesh is a macroporous, knitted, poly-L-lactide, poly-trimethylene carbonate copolymer monofilament mesh with the ProGrip™ technology, providing grips on one side of the mesh. A new poly-L-lactide, poly-trimethylene copolymer was developed to provide the required features for mechanical support during at least 20 weeks covering the critical healing period, including resistance to fatigue under cyclic loading conditions, as it occurs in patients. The yarns and mesh initial physical and biomechanical properties were characterized. Then, the mesh mechanical strength was evaluated over time. The mechanical properties of the proposed mesh were found to be above the generally recognized threshold value to mechanically support the repair site of a hernia over a 20-week period during in-vitro cyclic loading test. The mesh performance was evaluated in vivo using a published preclinical porcine model of hernia repair at 4-, 12- and 20-weeks post implantation. The burst strength of the hernia repair sites reinforced with the new mesh were higher at 4 & 12 weeks and comparable at 20 weeks to the one of the native abdominal walls. At all time points, the mesh was well tolerated with moderate inflammation and was fast integrated in the abdominal wall at 4 weeks. Particularly, the grips were nicely engulfed in the newly formed connective tissue. They must facilitate the anchoring of the mesh by their extension from the mesh and their mushroom shape. The preclinical data of the self-gripping resorbable mesh suggests that it has all the favorable characteristics for future clinical use during ventral hernia repair open procedures.Graphical

Synthesis of amine-bridged bis(phenolate) rare-earth metal alkoxides and their catalytic performance for the polymerization of trimethylene carbonate and L‑lactide

A series of rare-earth metal complexes stabilized by amine-bridged bis(phenolate) ligand were synthesized and employed as initiators for the polymerization of trimethylene carbonate (TMC) and L‑lactide (L-LA). One-pot reaction of the amine-bridged bis(phenol) LH2 (L = (CH3)2NCH2CH2N[CH2-(2-OH-3-tBu-5-OMe-C6H2)]2) with (C5H5)3RE(THF) or Nd[N(SiMe3)2]3 in a 1:1 molar ratio, followed by the treatment of 1 equiv. of ROH (R = (CF3)2CH, CF3CH2) gave the amine bridged bis(phenolate) rare-earth metal alkoxides LRE(OCH(CF3)2)(THF)n (RE = La (1), n = 2; RE = Nd (2), Y (3), Yb (4), Lu (5), n = 1) and LNd(OCH2CF3)(THF)2 (6) in good isolated yields. These complexes were efficient initiators for the homopolymerization of both TMC and L-LA. Kinetics of the polymerization of TMC and L-LA initiated by complex 6 was investigated, and the results showed that the polymerizations of L-LA and TMC were first order for the initiator and monomer concentrations.