Additive Summer School (Certificate Program) 2025

Abstract: Mg alloys are promising for clinical implementation of high-strength, biodegradable implants for e.g. bone fixation. This keynote will highlight recent progress in additive manufacturing of such alloys, including tailoring Mg alloy compositions and process parameters to enhance printability, mechanical integrity, and corrosion performance, while addressing challenges such as vaporization, defect formation, and phase instability. Emerging strategies for achieving predictable degradation, improved biocompatibility, and clinically relevant implant architectures will be discussed. Indeed, while additive manufacturing of Mg alloys through Powder Bed Fusion with Laser Beam (PBF‑LB) allows for high-resolution geometries and to some extent microstructural contral, the degradation behavior of printed parts still needs significant improvement.

Abstract: Microfluidic cavitation and jetting enable ultrafast, highly focused liquid microjets that can interact with soft matter at the mesoscale in ways unattainable with conventional tools. In this keynote, I will discuss how confined cavitation in microfluidic systems can be precisely tuned to control jet formation, dynamics, and penetration into soft substrates, including skin, thereby creating an inertial platform for minimally invasive bioengineering and medical applications. I will highlight how these phenomena bridge fundamental fluid dynamics with practical technologies for needle-free drug delivery and advanced mesoscale processing in medicine and biotechnology.

Abstract: As the field of minimally invasive surgery shifts toward the micro-scale, the gap between digital robotic design and clinical validation has become a primary bottleneck. Traditional benchtop testing often relies on simplified synthetic models or inconsistent porcine tissue, neither of which fully captures the nuanced haptic and structural complexities of human anatomy. This keynote explores the frontier of Bio-Digital Convergence, focusing on the development of high-fidelity, 3D-printed multi-material phantoms as a definitive validation platform for surgical micro-robotics.We present a collaborative framework for translating patient-specific imaging data into sophisticated physical models that mimic the heterogeneous mechanical properties of biological tissue. By utilizing advanced multi-material additive manufacturing, we have engineered phantoms that simulate varying physical properties—ranging from rigid bone structures to compliant vascular networks—within a single integrated print.

Key highlights of the presentation include:

• Development Methodology: A review of the end-to-end workflow, from MRI/CT segmentation to the selection of photopolymers that replicate tissue-specific viscoelasticity.
• Micro-Robotic Applicability: Data-driven results on how these phantoms enable the assessment of micro-robotic navigation, stability, and tool-tissue interaction across diverse surgical approaches.
• Validation & Outcomes: An analysis of surgical applicability achieved within 3D-printed environments, demonstrating the efficacy of these models in de-risking micro-robotic interventions before human trials.

By converging additive manufacturing with robotic engineering, we can create a "digital twin" of the surgical theater, providing a repeatable, ethical, and highly accurate environment for the next generation of precision medicine.

Abstract: 3D bioprinting offers a promising approach to fabricate customized scaffolds for tissue engineering and in vitro models [1]. One approach being investigated to improve bioinks for 3D bioprinting is the use of composite bioinks which incorporate ion releasing bioreactive (nano)particles. In this context, research at the FAU Institute of Biomaterials in Erlangen has focused on hydrogels based on alginate dialdehyde-gelatin (ADA-GEL) incorporating ion-releasing bioactive glass (BG) nanoparticles which can be designed to improve printability, mechanical properties, degradation behaviour and biological performance of the 3D bioprinted constructs. In this presentation we will describe the synthesis of ADA via oxidation of alginate [2], and the fabrication of mesoporous BG nanoparticles (MBGNs) via evaporation-induced self-assembly [3] and microemulsion-assisted [4] sol-gel methods. It will be shown that differences in particle size, surface area, and porosity of MBGNs influence the extent of ion release and the gelation of the inks. Different biologically active ions investigated are Cu, Zn, Mg, B, Li, and Ce. Ibn some cases, released ions acted as in situ crosslinking agents, leading to tunable gelation behavior and a defined processing window. With optimized printing parameters, the composite inks produced continuous filaments and three-dimensional structures with shape fidelity. Bioprinting studies were conducted using NIH/3T3 fibroblasts and C2C12 myoblasts [5] in order to establish the functionalities provided by the incorporated ion releasing MBGNs. Local ion release in the hydrogel can lead to significant effects on cellular response indicating potential advantages of utilizing biologically active ions as signaling agents instead of organic molecules or growth factors. For example, incorporating 0.1% w/v MBGNs in cell-laden constructs led to enhanced metabolic activity, highlighting the beneficial role of ion-releasing particles. This work demonstrated that ADA-GEL based composite hydrogels with ion-releasing particles provide reliable printability, tunable properties, and improved cellular responses, supporting their potential as an ionic medicine strategy for bioprinting applications. The work is funded by German Research Foundation, CRC/SFB225 B03.

[1] S. Heid, A.R. Boccaccini, Acta Biomater. 113 (2020) 1–22.
[2] B. Sarker et al., J. Mater. Chem. B 2 (2014) 1470–1482. 
[3] K. Zheng, et al., Journal of the American Ceramic Society 98 (2015) 30–38.
[4] K. Zheng, A.R. Boccaccini, Adv. Colloid Interface Sci. 249 (2017) 363–373.
[5] H. H. Lu, et al., Biomaterials Advances 172 (2025) 214233.