The development of advanced biomaterials for regenerative medicine and medical devices requires precise control over crosslinking mechanisms, printing resolution, and functional properties. In this study, we investigate photo-crosslinkable polyesters and gelatin networks, comparing chain-growth and step-growth crosslinking mechanisms and correlating these with photo-kinetics. By leveraging light-based 3D-printing techniques—including volumetric additive manufacturing (VAM), digital light projection (DLP), and two-photon polymerization (TPP)—we explore the relationship between polymer chemical design and printing resolution. Our findings demonstrate that step-growth thiol-ene polymerization enhances mechanical tunability and reduces brittleness compared to conventional acrylate-based chain-growth systems, while also enabling high-resolution fabrication.
Beyond static 3D structures, we extend our research into 4D-printing by exploiting shape memory properties of photo-crosslinkable polymers for minimally invasive tissue engineering. These materials can be programmed to undergo controlled shape transformations, broadening their applicability in medical devices such as stents. Additionally, we incorporate CT tracers into our polymer networks, enabling non-destructive in vivo monitoring of implants in line with the 3R principle.
Our research has direct implications for tissue engineering applications, including cornea regeneration, bone tissue engineering, and adipose tissue engineering. By combining tailored polymer networks with cutting-edge light-based fabrication strategies, we pave the way for next-generation biodegradable, patient-specific implants with controlled mechanical properties, high spatial resolution, and dynamic responsiveness. These findings contribute to the growing field of biofabrication, bridging fundamental polymer chemistry with translational biomedical applications.

Biobased and biodegradable poly-L-lactide (PLLA) stands out among piezoelectric polymers for its biocompatibility and environmental sustainability. Its piezoelectric response is closely related to crystallinity and polymer chain alignment, which is conventionally achieved by drawing techniques. The material technology implementation would strongly benefit from the demonstration of a single-step process capable of directly achieving a tailored piezoelectric morphology in PLLA from polymer melt. Fused deposition modelling (FDM) 3D printing can play this role, directly achieving tailored piezoelectric morphology in PLLA biopolymer by microscale control of molecular chain orientation through preparation parameters, such as 3D printing speed or bed temperature. The relationships of printing parameters-crystal phase content and texture-piezoelectric properties are comprehensively presented, and the key 3D printing parameters to obtain optimized piezoelectric chain morphologies are defined. Results reveal melt-based 3D printing to be a suitable technique for manufacturing biocompatible PLLA piezoelectric platforms that are also biodegradable. Commercial PLLA has been used, with which large shear piezoelectric coefficients d14 approaching 10 pC/N has been attained under optimized printing conditions. Additionally, the effects of molecular weight and printing pattern on the piezoelectric response are evaluated, offering insights into material performance enhancement.

Grants PID2023-152475OB-100, PID2021-122708OB-C33 and TED2021-130871B-C21, funded by MCIN/AEI/10.13039/501100011033, and by ERDF A way of making Europe by the “European Union” and the “European Union NextGeneration EU/PRTR”.

Additive manufacturing (AM) facilitates the creation of objects from digital designs, enabling sustainable prototyping that is rapid and cost-effective, especially for mass production. Approximately half of AM technology employ UV-curable resins, providing significantly advanced resolution compared to deposition-based procedures, making them appropriate for precision engineering. However, acrylate and methacrylate photochemistry, commonly used in these methods have significant toxicity concerns and lead to non-biodegradable carbon backbones. Herein we design and synthesize unique and novel photomonomers based on amino acid phosphoramides (APAs). The phosphoramide backbone endures hydrolysis under physiological conditions, releasing biocompatible byproducts such as phosphates and amino acids, mimicking natural tissue components ¹. The incorporation of phosphorus-nitrogen bonds facilitates controlled hydrolysis, while the selection of amino acid substituents allows for fine-tuning of degradation rates. Variable APA backbone functional groups allow diverse monomer synthesis with various hydrophilic and hydrophobic properties, resulting in diverse degradation profiles. For example, APA copolymerization with dithiols facilitates hydrogel fabrication via thiol-yne photopolymerization ². Alternatively, vinyl ester and carbonate groups enable single-component, free-thiol resins ³. These monomers can be combined with co-monomers to adjust viscosity for various 3D printing techniques, including inkjet, bioprinting, and digital light processing (DLP). This will enable us to provide biodegradable photochemical 3D printing resins and print precision materials for applications such as tissue engineering scaffolds and wound care. The authors gratefully acknowledge funding by the ACCURE project, supported by the European Regional Development Fund (ERDF) under Project ID ATCZ00083.

Since the approval of the first commercial tablet in 2015, additive manufacturing attracted much attention for designing complex personalized drug delivery systems.[1,2] 3D printing offers various benefits such as low cost flexible pharmaceutical dose design and optimization, reduced lead times, and decentralized production. Oral delivery of macromolecules such as therapeutic peptides or oligonucleotides is hindered by harsh gastrointestinal tract (GI) and defensive intestinal epithelial barriers. Despite different methods introduced to overcome these obstacles, the delivery of oral biotherapeutic formulations remains challenging with low bioavailability.[3]

In the current work, an extendable 3D printed drug delivery device based on degradable polymeric material is designed to enhance bioavailability through the absorption in the small intestine of a medium-molecular weight peptide. The delivery devices were synthesized using poly(β-amino ester) [PBAE] diacrylate photo-polymerizable inks. PBAEs have been synthesized via Michael addition by combining different amines and diacrylate molecules. The peptide was introduced in the 3D-printing formulations via intermolecular interactions. Precise tuning of PBAE composition led to hydrolytically or bioreducibly degradable systems loaded with a sufficient peptide dose. Moreover, release studies in different conditions mimicking the GI fluids showed a controlled release over a relevant period.

3D printing is an attractive technology in dentistry, as it enables a fast and cost-effective manufacturing of customized dental materials [1-2] Moreover, the possibility to print several objects at once represents a considerable advantage. DLP (digital light processing) and SLA (stereolithography) are the most commonly used 3D printing technologies in dentistry in order to produce with high precision various materials such as tooth models, orthodontic workpieces (e.g. splints), wax models for metal casting and press ceramics, denture bases and denture teeth. The development of 3D printing denture bases is particularly challenging as these materials must exhibit high mechanical properties (high flexural strength and modulus) as well as high fracture toughness. Due to the low reactivity and high volatility of MMA, conventional MMA-based denture bases are hardly suitable for 3D-printing. Therefore, 3D printing resins mainly contain dimethacrylates. Unfortunately, networks resulting from the curing of dimethacrylate mixtures are typically brittle and not adapted for the preparation of tough denture materials. There is therefore a need for efficient toughening technologies that would be compatible with the 3D printing process.
In this contribution, two main technologies based on the toughening of dimethacrylate networks using block copolymers (BCPs) will be presented. The first one consists in the preparation of low crosslink density networks containing BCPs [3-5], whereas the second one deals with the incorporation of such toughening agents to homogeneous networks which are prepared via photopolymerization of dimethacrylates in presence of a chain transfer agent.

Additive manufacturing processes are attracting increasing interest in dentistry as they enable the efficient production of patient-specific parts with high precision. Stereolithography (SLA) and digital light processing (DLP) are already well established for the production of a wide range of parts such as aligners, orthodontic splints, drilling templates and dental models [1,2]. There is also considerable interest in using 3D printing to replace conventional methods of manufacturing dentures, which have traditionally relied on injection moulding of thermally curable methyl(meth)acrylate (MMA) based materials. In addition to high flexural strength and modulus, dental prostheses must also exhibit high fracture toughness. The latter is a major challenge, as MMA-based materials are not suitable for 3D printing due to the low reactivity and volatility of MMA, and polymerization of the multifunctional (meth)acrylates used in their place leads to highly cross-linked and brittle parts. A potential solution to this challenge lies in the use of low crosslinking resin systems comprising a significant amount of highly reactive monofunctional (meth)acrylates and toughening agents.

Previously, we proposed the use of precisely designed block copolymers (BCPs) acting as toughening agents by self-assembly in low crosslink density urethane (meth)acrylate networks [3,4,5]. Until now, only the physical properties of bulk cured materials were investigated. The present contribution deals with DLP 3D printing of BCP containing (meth)acrylate formulations and focuses on the influence of different post-treatment parameters (irradiation intensity, irradiation time, temperature) on key properties (flexural strength/modulus, fracture toughness, double bond conversion, glass transition temperature and network density) of the cured materials.