Porous photo-crosslinked hybrid networks based on poly(trimethylene carbonate-co-ε-caprolactone) and recombinant human-like collagen.

Hybrid hydrogel networks were prepared from recombinant human-like collagen (rh-collagen) and poly(trimethylene carbonate-co-ε-caprolactone) (P (TMC-co-ε-CL)) to overcome the mechanical and bioactivity limitations associated with the respective individual networks. Both polymers were functionalised with methacrylic anhydride to yield photo-crosslinkable materials. Porous hybrid networks of different compositions were prepared by photo-crosslinking frozen mixtures of solutions of the functionalized polymers in acidified DMSO.

Physicochemical Characterization and Immunomodulatory Activity of Polyelectrolyte Multilayer Coatings Incorporating an Exopolysaccharide from .

Immunoregulatory polysaccharides from probiotic bacteria have potential in biomedical engineering. Here, a negatively charged exopolysaccharide from with confirmed immunoregulatory activity (EPS624) was applied in multilayered polyelectrolyte coatings with positively charged chitosan. EPS624 and coatings (1, 5, and 10 layers and alginate-substituted) were characterized by the zeta potential, dynamic light scattering, size exclusion chromatography, scanning electron microscopy, and atomic force microscopy.

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 30 kg mol 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.

Enzymatic post-crosslinking of printed hydrogels of methacrylated gelatin and tyramine-conjugated 8-arm poly(ethylene glycol) to prepare interpenetrating 3D network structures.

Methacrylated gelatin (GelMA) has been intensively studied as a 3D printable scaffold material in tissue regeneration fields, which can be attributed to its well-known biological functions. However, the long-term stability of photo-crosslinked GelMA scaffolds is hampered by a combination of its fast degradation in the presence of collagenase and the loss of physical crosslinks at higher temperatures. To increase the longer-term shape stability of printed scaffolds, a mixture of GelMA and tyramine-conjugated 8-arm PEG (8PEGTA) was used to create filaments composed of an interpenetrating network (IPN).

Hybrid Networks of Hyaluronic Acid and Poly(trimethylene carbonate) for Tissue Regeneration.

To improve the mechanical performance of hyaluronic acid (HA)-based hydrogels, we prepared novel hybrid hydrogels consisting of hydrophilic HA and hydrophobic poly(trimethylene carbonate) (PTMC). Both polymers were functionalized with methacrylic anhydride, yielding HAMA and PTMC-tMA. Hybrid networks with different ratios of PTMC-tMA:HAMA were prepared by photo-cross-linking, using DMSO pH 2.

Biocompatibility and degradation comparisons of four biodegradable copolymeric osteosynthesis systems used in maxillofacial surgery: A goat model with four years follow-up.

Applying biodegradable osteosyntheses avoids the disadvantages of titanium osteosyntheses. However, foreign-body reactions remain a major concern and evidence of complete resorption is lacking. This study compared the physico-chemical properties, histological response and radiographs of four copolymeric biodegradable osteosynthesis systems in a goat model with 48-months follow-up.

Local Bacteriophage Delivery for Treatment and Prevention of Bacterial Infections.

As viruses with high specificity for their bacterial hosts, bacteriophages (phages) are an attractive means to eradicate bacteria, and their potential has been recognized by a broad range of industries. Against a background of increasing rates of antibiotic resistance in pathogenic bacteria, bacteriophages have received much attention as a possible "last-resort" strategy to treat infections. The use of bacteriophages in human patients is limited by their sensitivity to acidic pH, enzymatic attack and short serum half-life.

3D Printing of large-scale and highly porous biodegradable tissue engineering scaffolds from poly(trimethylene-carbonate) using two-photon-polymerization.

The introduction of two-photon polymerization (2PP) to the field of tissue engineering and regenerative medicine (TERM) has led to great expectations for the production of scaffolds with an unprecedented degree of complexity and tailorable architecture. Unfortunately, resolution and size are usually mutually exclusive when using 2PP, resulting in a lack of highly-detailed scaffolds with a relevant size for clinical application. Through the combination of using a highly reactive photopolymer and optimizing key printing parameters, we propose for the first time a biodegradable and biocompatible poly(trimethylene-carbonate) (PTMC)-based scaffold of large size (18 × 18 × 0.

Poly(Aspartic Acid) Functionalized Poly(ϵ-Caprolactone) Microspheres with Enhanced Hydroxyapatite Affinity as Bone Targeting Antibiotic Carriers.

Bone infection is a feared complication for patients with surgically fixed bone fractures and local antibiotic delivery is important in prophylaxis and treatment of these infections. Recent studies indicated that can penetrate bone tissue through micron-sized canaliculi and evade systemic and currently available local antibiotic treatments. Targeting bacteria within the bone requires highly efficient delivery of antimicrobials to the infected bone tissue.

Triply Periodic Minimal Surfaces (TPMS) for the Generation of Porous Architectures Using Stereolithography.

A new generation of sophisticated tissue engineering scaffolds are developed using the periodicity of trigonometric equations to generate triply periodic minimal surfaces (TPMS). TPMS architectures display minimal surface energy that induce typical pore features and surface curvatures. Here we described a series of TPMS geometries and developed a procedure to build such scaffolds by stereolithography using biocompatible and biodegradable photosensitive resins.

Leachable Poly(Trimethylene Carbonate)/CaCO Composites for Additive Manufacturing of Microporous Vascular Structures.

The aim of this work was to fabricate microporous poly(trimethylene carbonate) (PTMC) vascular structures by stereolithography (SLA) for applications in tissue engineering and organ models. Leachable CaCO particles with an average size of 0.56 μm were used as porogens.

Development of bone seeker-functionalised microspheres as a targeted local antibiotic delivery system for bone infections.

Objective: Bone infections are challenging to treat because of limited capability of systemic antibiotics to accumulate at the bone site. To enhance therapeutic action, systemic treatments are commonly combined with local antibiotic-loaded materials. Nevertheless, available drug carriers have undesirable properties, including inappropriate antibiotic release profiles and nonbiodegradability.

Morphological and biomechanical effects of annulus fibrosus injury and repair in an ovine cervical model.

Tissue engineering repair of annulus fibrosus (AF) defects has the potential to prevent disability and pain from intervertebral disc (IVD) herniation and its progression to degeneration. Clinical translation of AF repair methods requires assessment in long-term large animal models. An ovine AF injury model was developed using cervical spinal levels and a biopsy-type AF defect to assess composite tissue engineering repair in 1-month and 12-month studies.

Orbital floor repair using patient specific osteoinductive implant made by stereolithography.

The orbital floor (OF) is an anatomical location in the craniomaxillofacial (CMF) region known to be highly variable in shape and size. When fractured, implants commonly consisting of titanium meshes are customized by plying and crude hand-shaping. Nevertheless, more precise customized synthetic grafts are needed to meticulously reconstruct the patients' OF anatomy with better fidelity.

Engineering 3D parallelized microfluidic droplet generators with equal flow profiles by computational fluid dynamics and stereolithographic printing.

Microfluidic droplet generators excel in generating monodisperse micrometer-sized droplets and particles. However, the low throughput of conventional droplet generators hinders their clinical and industrial translation. Current approaches to parallelize microdevices are challenged by the two-dimensional nature of the standard fabrication methods.

The Trimerization of Isocyanate-Functionalized Prepolymers: An Effective Method for Synthesizing Well-Defined Polymer Networks.

For the study of polymer networks, having access to polymer networks with a controlled and well-defined microscopic network structure is of great importance. However, typically, such networks are difficult to synthesize. In this work, a simple, effective, and widely applicable method is presented for synthesizing polymer networks with a well-defined network structure.

Synthesis and characterization of rGO-graft-poly(trimethylene carbonate) for nerve regeneration conduits.

Graphene-graft-polymer has been used to improve the compatibility between graphene and a polymer matrix, and to further enhance electrical, mechanical and biological properties of polymer/graphene composites. In this study, poly(trimethylene carbonate) (PTMC) was successfully grafted onto graphene surface via 'grafting from' method. Reduced graphene oxide (rGO) initiator was synthesized by azido ethanol reaction with graphene oxide (GO) at high temperature.

Fabrication of poly (trimethylene carbonate)/reduced graphene oxide-graft-poly (trimethylene carbonate) composite scaffolds for nerve regeneration.

One of the key challenges for neural tissue engineering is to exploit functional materials to guide and support nerve regeneration. Currently, reduced graphene oxide (rGO), which is well-known for its unique electrical and mechanical properties, has been incorporated into biocompatible polymers to manufacture functional scaffolds for nerve tissue engineering. However, rGO has poor dispersity in polymer matrix, which limits its further application.

A Zebrafish Embryo Model for In Vivo Visualization and Intravital Analysis of Biomaterial-associated Staphylococcus aureus Infection.

Biomaterial-associated infection (BAI) is a major cause of the failure of biomaterials/medical devices. Staphylococcus aureus is one of the major pathogens in BAI. Current experimental BAI mammalian animal models such as mouse models are costly and time-consuming, and therefore not suitable for high throughput analysis.

Osteogenic magnesium incorporated into PLGA/TCP porous scaffold by 3D printing for repairing challenging bone defect.

Bone defect repair is a challenging clinical problem in musculoskeletal system, especially in orthopaedic disorders such as steroid associated osteonecrosis (SAON). Magnesium (Mg) as a biodegradable metal with properly mechanical properties has been investigating for a long history. In this study, Mg powder, poly (lactide-co-glycolide) (PLGA), β-tricalcium phosphate (β-TCP) were the elements to formulate a novel porous PLGA/TCP/Mg (PTM) scaffolds using low temperature rapid prototyping (LT-RP) technology.

Zwitterionic Functionalizable Scaffolds with Gyroid Pore Architecture for Tissue Engineering.

Stereolithography-assisted fabrication of hydrogels of carboxybetaine methacrylamide (CBMAA) and a α,ω-methacrylate poly(d,l-lactide-block-ethylene glycol-block- d,l-lactide) (MA-PDLLA-PEG-PDLLA-MA) telechelic triblock macromer is presented. This technique allows printing complex structures with gyroid interconnected porosity possessing extremely high specific area. Hydrogels are characterized by infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and laser scanning confocal microscopy (LSCM).

Enhanced mechanical and cell adhesive properties of photo-crosslinked PEG hydrogels by incorporation of gelatin in the networks.

Although synthetic polymers may have suitable physicochemical properties for biomedical applications, biological properties are generally lacking. Poly(ethylene glycol) (PEG) is a frequently used polymer for the preparation of hydrogels. Due to its hydrophilic character, however, cellular interactions with PEG hydrogels are minimal or absent.

Photo-crosslinked synthetic biodegradable polymer networks for biomedical applications.

Photo-crosslinked synthetic biodegradable polymer networks are highly interesting materials for utilization in biomedical applications such as drug delivery, cell encapsulation and tissue engineering scaffolds. Varying the architecture, chemistry, degree of functionalization and molecular weight of the macromer precursor molecules results in networks with a wide range of physical- and mechanical properties, crosslinking densities, degradation characteristics and thus in potential applications. Photo-crosslinked networks can easily be prepared and have the possibility to entrap a wide range of (biologically active) substances and cells.

Thermoplastic PCL--PEG--PCL and HDI Polyurethanes for Extrusion-Based 3D-Printing of Tough Hydrogels.

Novel tough hydrogel materials are required for 3D-printing applications. Here, a series of thermoplastic polyurethanes (TPUs) based on poly(ɛ-caprolactone)--poly(ethylene glycol)--poly(ɛ-caprolactone) (PCL--PEG--PCL) triblock copolymers and hexamethylene diisocyanate (HDI) were developed with PEG contents varying between 30 and 70 mol%. These showed excellent mechanical properties not only when dry, but also when hydrated: TPUs prepared from PCL--PEG--PCL with PEG of Mn 6 kg/mol (PCL₇-PEG₆-PCL₇) took up 122 wt.

A drug eluting poly(trimethylene carbonate)/poly(lactic acid)-reinforced nanocomposite for the functional delivery of osteogenic molecules.

Background: Poly(trimethylene carbonate) (PTMC) has wide biomedical applications in the field of tissue engineering, due to its biocompatibility and biodegradability features. Its common manufacturing involves photofabrication, such as stereolithography (SLA), which allows the fabrication of complex and controlled structures. Despite the great potential of SLA-fabricated scaffolds, very few examples of PTMC-based drug delivery systems fabricated using photo-fabrication can be found ascribed to light-triggered therapeutics instability, degradation, side reaction, binding to the macromers, etc.