3D-printed Platform Research Articles

Miniaturized 3D-printed ratiometric electrochemical immunosensing platform for ultrasensitive detection of depression biomarker Apo-A4

Miniaturized 3D-printed ratiometric electrochemical immunosensing platform for ultrasensitive detection of depression biomarker Apo-A4

Novel bioassays based on 3D-printed device for sensing of hypoxia and p53 pathway in 3D cell models.

Cell-based assays are widely exploited for drug screening and biosensing, providing useful information about bioactivity of target analytes and complex biological samples. It is well recognized that 3D cell models are required to achieve highly valuable information, also from the perspective of replacing animal models. However, bioassays relying on 3D cell models are generally highly demanding in terms of facilities, equipment, and skilled personnel requirements. To reduce cost, increase sustainability, and provide a flexible 3D cell-based platform for bioassays, we here report a novel approach based on a 3D-printed microtissue device. To assess the suitability of this strategy for reporter gene technology, we selected to monitor two molecular pathways which were of interest in several applications, hypoxia signaling and the p53 pathway. The investigation of such pathways is highly relevant in fields spanning from drug screening to bioactivity monitoring for industrial by-product valorization. Microtissues of human hepatocarcinoma (HepG2) and human embryonic kidney (Hek293T) cell lines were obtained with a low-cost and sustainable chip platform and bioassays were developed to monitor the hypoxia-inducible factors (HIFs) and the p53 tumor suppressor pathway. HepG2 and Hek293T 3D cell models were genetically engineered to express the Luc2P from Photinus pyralis firefly either under the regulation of p53 or HIF response elements. The bioassays allowed quantitative assessment of hypoxia and tumoral activity with 1,10-phenanthroline for HIF and with doxorubicin for p53 pathway activation, respectively, showing good potential for applications of this sustainable and low-cost 3D-printed microfluidic platform for bioactivity analyses, drug screening, and precision medicine.

3D-printed modular platform for path-customizable liquids transport

Spontaneous liquid transport is increasingly being applied in various fields such as microfluidics, fuel cells, phase change heat transfer, water harvesting, etc. However, long-distance spontaneous liquid transport with path-customizable motion trajectories is still challenging. Drawing multi-inspirations from the wedge-shaped structures of iris petals, the continuous structures of bamboo joints, and the microgroove structures of Nepenthes mouth edge, we fabricate a modular, pump-free biomimetic liquid transport platform by 3D printing and surface modification. The platform is composed of sequential wedge notches, and a crescent-shaped groove is designed at the joint of every two connected wedge structures. The platform is characterized by path-customizable liquid transport trajectories and can be used to achieve long-distance liquid transport without the need of external energy fields, and the multi-level nested structures along the depth significantly facilitates the liquid transport. Experimental study and theoretical force analysis show that the crescent-shaped grooves enable the liquid to overcome joint barriers by converting potential energy accumulated at joints into kinetic energy, achieving a maximum velocity of 18 mm/s. Taking advantage of the flexibility of 3D printing and long-distance transport capability, the modular structure of the platform enables customization of the transport distance and trajectory. By assembling 14 bamboo-like wedge-shaped units in series, we realized a transport distance up to 350 mm, which could be further increased by connecting more units. Furthermore, we develop various modular and multifunctional liquid transport platforms for anti-gravity transport, liquid diversion, and customized transport trajectories, which demonstrate that our design strategy could be an available solution for path-customizable liquids transport in fields like bio-sensing, fuel cells, etc.

Highly fluorescent nitrogen doped carbon dots as analytical probe for sensitive detection of curcumin through smartphone integrated 3D-printed platform: A new horizon in food safety

COVID-19 pandemic has significantly influenced the dietary habits of humans, emphasizing the incorporation of natural ingredients to enhance immunity towards viral and bacterial infections. Curcumin (Cur), a widely used traditional medicine in various Asian countries and a natural coloring agent, has gained popularity, leading to surge in its usage specially in post COVID-19 era. This surge has led to increased scrutiny of the potential side effects of excessive Cur use, with recent reports suggesting it may result in inactivation of DNA and reduce adenosine triphosphate levels, leading to health risks. In this work, we synthesized highly fluorescent nitrogen-doped carbon dots with a photoluminescence quantum yield of 72.9 % for the sensitive and selective detection of Cur. The developed fluorescent probe exhibits excellent sensory response towards Cur within a concentration range of 0.081–51.45 µM, achieving an ultra-low detection limit of 15.91 nM. The sensor was successfully tested on real food samples like ginger powder, turmeric powder, and curry powder, demonstrating good recovery rates. To assess the practicality of the sensor system, we developed a 3D-printed smartphone-integrated device platform for curcumin detection through fluorescence image analysis. This developed platform exhibited promising results, achieving a limit of detection (LoD) of 132.28 nM across a curcumin concentration range of 0.13–54.00 µM. This device platform holds significant potential for the development of efficient sensors for real-time detection of Cur in food samples.

Quantification of elastic modulus variations during zebrafish embryo development using a 3D-printed microfluidic platform

Reliable indicators to assess embryo quality are critical for the in vitro fertilization. Increasing evidence suggests that elasticity is emerging as a potential marker to evaluate the early development of embryos. This paper introduces a 3D-printed microfluidic device to measure the elastic modulus of zebrafish embryos deformed in a circular constriction channel. Firstly, numerical simulation was performed to analyze the impact of inlet pressure, embryo size and constriction channel diameter on the maximum protrusion length of the embryo. Subsequently, the zebrafish embryos were deformed using the device to record the protrusion length which was automatically measured using U-net, before the power-law rheological model was employed to calculate the elastic modulus. Experiments showed the power-law exponent and embryo elasticity were stable as the inlet pressure was not less than 250 mbar. Embryo culturing after squeezes revealed that embryos could maintain normal development even after multiple squeezes at 150 mbar while higher pressure may be fatal. Afterward, the deformation of the yolk was found to increase elasticity by 60.4% compared to cases where only the chorion envelope was deformed. Finally, the elasticity variation of zebrafish embryos was measured for 17hours. It revealed that the elasticity initially increased from hour 1 to hour 7-10 and then returned to approximately the original value during culture from the cleavage to the segmentation stages. The system with the ability of precise and long-term assessment of embryo elasticity may find valuable application potentials in the mechanical evaluation and sorting of embryos.

Single-molecule detection and super-resolution imaging with a portable and adaptable 3D-printed microscopy platform (Brick-MIC).

Over the past decades, single-molecule and super-resolution microscopy have advanced and represent essential tools for life science research. There is, however, a growing gap between the state of the art and what is accessible to biologists, biochemists, medical researchers, or labs with financial constraints. To bridge this gap, we introduce Brick-MIC, a versatile and affordable open-source 3D-printed microspectroscopy and imaging platform. Brick-MIC enables the integration of various fluorescence imaging techniques with single-molecule resolution within a single platform and exchange between different modalities within minutes. We here present variants of Brick-MIC that facilitate single-molecule fluorescence detection, fluorescence correlation spectroscopy, time-correlated single-photon counting and super-resolution imaging (STORM and PAINT). Detailed descriptions of the hardware and software components, as well as data analysis routines, are provided, to allow non-optics specialists to operate their own Brick-MIC with minimal effort and investments. We foresee that our affordable, flexible, and open-source Brick-MIC platform will be a valuable tool for many laboratories worldwide.

A 3D Printing Platform for Design and Manufacturing of Multi-Functional Cementitious Construction Components and Its Validation for a Post-Tensioned Beam.

Three-dimensional printing of cementitious materials for construction has been extensively investigated in recent years, with several demonstration projects successfully carried out. These efforts aim to leverage the printing process to achieve more efficient production of components compared to conventional concrete technologies. This includes both the process itself (eliminating the formwork stage) and the flexibility in producing complexly shaped elements. To maximize the potential of 3D printing in the construction industry, additional steps must be taken, grounded in a holistic view of the entire process. This involves integration of the production chain, including design, materials, and manufacturing of components, to create elements with optimal performance, encompassing structural, environmental, and architectural aspects. Such multi-functionality requires the viewing of 3D printing not just as a production technology but as a platform enabling the integration of all these components. To advance this approach, quantitative tools are developed to optimize the following three key components: material composition; manufacturing parameters to ensure buildability; and design tools to optimize multiple performance criteria, particularly structural and architectural shape. A demonstration component, namely a post-tensioned beam, featuring two multi-functional characteristics-structural and architectural-is designed, produced, and evaluated. The scientific concepts and research tools used to develop these quantitative design tools are multidisciplinary, including rheological characterization, control of the internal structure and composition of granular materials, simulation of the mechanical behavior of green material during printing, and the hardened properties of the components, all utilizing structural optimization to enhance performance.

Portable cell imprinted polymer-based microfluidic sensor for bacteria detection in real water

Cell-imprinted polymer (CIP) based optical biosensors have transformed point-of-care detection. However, challenges remain in their portability and detection sensitivity, time, and cost. Herein, we present an imprinted polymer-based low-cost microfluidic device integrated into a portable enclosure that enables rapid and sensitive bacteria detection in real water. A portable 3D-printed platform was custom-designed, housing all essential detection components, i.e., pumping and fluorescent imaging units and the microfluidic sensor. CIP coated magnetic microparticles (MPs) with affinity to bacteria were manipulated inside the magnetophoretic microfluidic device at an optimized flow rate of 0.01 mL/min for bacteria capturing. Fluorescent imaging pre- and post-bacteria capture facilitated quantification of fluorescence intensity changes as bacteria were trapped by the CIP-MPs. The sensor’s dose–response curve established limits of detection (LOD) and quantification (LOQ) at 8 × 103 and 6 × 105 CFU/mL, respectively, within a dynamic range of 103 to 109 CFU/mL. It specifically detected E. coli, distinguishing it from non-specific bacteria like Salmonella and Sarcina. In real pond water tests, our sensor detected 2 × 10⁶ CFU/mL, matching a central lab’s result of 2.33 × 10⁶ CFU/mL, demonstrating its effectiveness for real-water monitoring. While further enhancements are needed for improving the specificity in complex environmental matrices and broader bacterial strain detection, the sensor’s simplicity and portability highlight its potential for practical potential.

Sustained dual delivery of metronidazole and viable Lactobacillus crispatus from 3D-printed silicone shells

Bacterial vaginosis (BV) is an imbalance of the vaginal microbiome in which there are limited lactobacilli and an overgrowth of anaerobic and fastidious bacteria such as Gardnerella. The propensity for BV recurrence is high, and therapies involving multiple treatment modalities are emerging to meet this need. However, current treatments requiring frequent therapeutic administration are challenging for patients and impact user compliance. Three-dimensional (3D)-printing offers a novel alternative to customize platforms to facilitate sustained therapeutic delivery to the vaginal tract. This study designed a novel vehicle intended for dual sustained delivery of both antibiotic and probiotic. 3D-printed compartmental scaffolds consisting of an antibiotic-containing silicone shell and a core containing probiotic Lactobacillus were developed with multiple formulations including biomaterials sodium alginate (SA), polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyethylene oxide (PEO), and kappa-carrageenan (KC). The vehicles were loaded with 50 μg of metronidazole/mg polymer and 5 × 107 CFU of L. crispatus/mg scaffold. Metronidazole-containing shells exhibited cumulative drug release of 324.2 ± 31.2 μg/mL after 14 days. Multiple polymeric formulations for the probiotic core demonstrated cumulative L. crispatus recovery of >5 × 107 CFU/mg scaffold during this timeframe. L. crispatus-loaded polymeric formulations exhibited ≥2 log CFU/mL reduction in free Gardnerella in the presence of VK2/E6E7 vaginal epithelial cells. As a first step towards the goal of facilitating patient compliance, this study demonstrates in vitro effect of a novel 3D-printed dual antibiotic and probiotic delivery platform to target BV.

Prophylactic and therapeutic cancer vaccine with continuous localized immunomodulation

Selective in vivo immune cell manipulation offers a promising strategy for cancer vaccines. In this context, spatiotemporal control over recruitment of specific cells, and their direct exposure to appropriate immunoadjuvants and antigens are key to effective cancer vaccines. We present an implantable 3D-printed cancer vaccine platform called the ‘NanoLymph’ that enables spatiotemporally-controlled recruitment and manipulation of immune cells in a subcutaneous site. Leveraging two reservoirs each for continuous immunoadjuvant release or antigen presentation, the NanoLymph attracts dendritic cells (DCs) on site and exposes them to tumor-associated antigens. Upon local antigen-specific activation, DCs are mobilized to initiate a systemic immune response. NanoLymph releasing granulocyte-macrophage colony-stimulating factor and CpG-oligodeoxynucleotides with irradiated whole cell tumor lysate inhibited tumor growth of B16F10 murine melanoma in a prophylactic and therapeutic vaccine setting. Overall, this study presents the NanoLymph as a versatile cancer vaccine development platform with replenishable and controlled local release of antigens and immunoadjuvants.

Development of a biocompatible 3D hydrogel scaffold using continuous liquid interface production for the delivery of cell therapies to treat recurrent glioblastoma.

Glioblastoma (GBM) is the most common primary malignant brain tumor diagnosed in adults, carrying with it an extremely poor prognosis and limited options for effective treatment. Various cell therapies have emerged as promising candidates for GBM treatment but fail in the clinic due to poor tumor trafficking, poor transplantation efficiency, and high systemic toxicity. In this study, we design, characterize, and test a 3D-printed cell delivery platform that can enhance the survival of therapeutic cells implanted in the GBM resection cavity. Using continuous liquid interface production (CLIP) to generate a biocompatible 3D hydrogel, we demonstrate that we can effectively seed neural stem cells (NSCs) onto the surface of the hydrogel, and that the cells can proliferate to high densities when cultured for 14 days in vitro. We show that NSCs seeded on CLIP scaffolds persist longer than freely injected cells in vivo, proliferating to 20% higher than their original density in 6 days after implantation. Finally, we demonstrate that therapeutic fibroblasts seeded on CLIP more effectively suppress tumor growth and extend survival in a mouse model of LN229 GBM resection compared to the scaffold or therapeutic cells alone. These promising results demonstrate the potential to leverage CLIP to design hydrogels with various features to control the delivery of different types of cell therapies. Future work will include a more thorough evaluation of the immunological response to the material and improvement of the printing resolution for biocompatible aqueous resins.

Modulable 3D-printed plantibody-laden platform enabling microscale affinity extraction and ratiometric front-face fluorescence detection of microcystin-LR in marine waters

A 3D-printed stereolithographic platform for selective biorecognition is designed to enable convective microscale affinity extraction of microcystin-LR (MC-LR) followed by direct solid-phase optosensing exploiting ratiometric front-face fluorescence spectroscopy. For this purpose, a recombinant monoclonal plantibody (recAb) is covalently attached to a 3D-printed structure for sorptive immunoextraction, whereupon the free and unbound primary amino moieties of the recAb are derivatized with a fluorescent probe. The fluorophore-recAb-MC-LR laden device is then accommodated in the cuvette holder of a conventional fluorometer without any instrumental modification for the recording of the solid-phase fluorescence emission. Using Rodbard’s four-parameter sigmoidal function, the 3D-printed bioselective platform features a limit of detection (LOD) of 28 ng L−1 using a sample volume of 500 mL, device-to-device reproducibility down to 12%, and relative recoveries ranging from 91 to 100% in marine waters. Printed prototypes are affordable, just 0.4 € per print and ≤ 10 € per device containing recAb. One of the main assets of the miniaturized immunoextraction device is that it performs comparably well in terms of analytical figures of merit with costly mass spectrometric-based analytical methodologies, such as HPLC–MS/MS. The device is readily applicable to high-matrix samples, such as seawater, as opposed to previous biosensing platforms, just applied to freshwater systems.Graphical abstract

Feasibility of continuous switching 3D printing on surimi

Continuous switching 3D printing that allows multiple materials printed in a single nozzle was introduced to verify its applicability to the food system, which aims to improve the switching ability and manufacturing precision of multi-material 3D printed food. By integrating a self-developed 3D printing platform with logical adjustments of extrusion pressure and 3D motion, the feasible continuous switching of surimi was achieved. Moreover, employing a dual-channel continuous switching extrusion nozzle, the study elucidated the influence of surimi rheological properties on the interface behavior between pastes during extrusion. Through the analysis of fluid dynamics behavior of channel flow and utilization of simulation technology, a channel extension solution was formulated. Extending the length of the non-extrusion channel to 15 mm effectively prevented intrusion over 4 mm at an extrusion speed of 40 mm/s. This study managed to repetitively switch between two kinds of surimi pastes within a 2 mm unit length. Meanwhile, three types of 3D printing modes were established based on the control of Gcode, and the corresponding model offset correction enabled precise deposition of 2 mm × 1 mm units. The research also succeeded in 3D printing complex structures, such as meat-fat structure of beef based on surimi.

Single-molecule detection and super-resolution imaging with a portable and adaptable 3D-printed microscopy platform (Brick-MIC).

Over the past decades, single-molecule and super-resolution microscopy have advanced and represent essential tools for life science research. There is,however, a growing gap between the state-of-the-art and what is accessible to biologists, biochemists, medical researchers or labs with financial constraints. To bridge this gap, we introduce Brick-MIC, a versatile and affordable open-source 3D-printed micro-spectroscopy and imaging platform. Brick-MIC enables the integration of various fluorescence imaging techniques with single-molecule resolution within a single platform and exchange between different modalities within minutes. We here present variants of Brick-MIC that facilitate single-molecule fluorescence detection, fluorescence correlation spectroscopy and super-resolution imaging (STORM and PAINT). Detailed descriptions of the hardware and software components, as well as data analysis routines are provided, to allow non-optics specialist to operate their own Brick-MIC with minimal effort and investments. We foresee that our affordable, flexible, and opensource Brick-MIC platform will be a valuable tool for many laboratories worldwide.

Enhancing the Concentration Capability of Nonsupported Electrically Driven Liquid-Phase Microextraction through Programmable Flow Using an All-In-One 3D-Printed Optosensor: A Proof of Concept.

A versatile millifluidic 3D-printed inverted Y-shaped unit (3D-YSU) was prototyped to ameliorate the concentration capability of nonsupported microelectromembrane extraction (μ-EME), exploiting optosensing detection for real-time monitoring of the enriched acceptor phase (AP). Continuous forward-flow and stop-and-go flow modes of the donor phase (DP) were implemented via an automatic programmable-flow system to disrupt the electrical double layer generated at the DP/organic phase (OP) interface while replenishing the potentially depleted layers of analyte in DP. To further improve the enrichment factor (EF), the organic holding section of the OP/AP channel was bifurcated to increase the interfacial contact area between the DP and the OP. Exploiting the synergistic assets of (i) the continuous forward-flow of DP (1050 μL), (ii) the unique 3D-printed cone-shaped pentagon cross-sectional geometry of the OP/AP channel, (iii) the bifurcation of the OP that creates an inverted Y-shape configuration, and (iv) the in situ optosensing of the AP, a ca. 24 EF was obtained for a 20 min extraction using methylene blue (MB) as a model analyte. The 3D-YSU was leveraged for the unsupervised μ-EME and the determination of MB in textile dye and urban wastewater samples, with relative recoveries ≥88%. This is the first work toward analyte preconcentration in μ-EME with in situ optosensing of the resulting extracts using 3D-printed millifluidic platforms.

Innovative microfluidic thread electroanalytical device with automated injector: A simple, green and upgraded analytical platform for the fast and sensitive analysis of ferrous ions

Cotton thread-based microfluidic devices are attractive for analytical procedures due to advantages that include affordable cost, low consumption of reagents and minimal production of waste. The coupling of cotton-based devices to electrochemical detection, known as microfluidic thread electroanalytical device (µTED), has demonstrated vast potential. However, some aspects in the µTED concept can still be improved, such as sample injection, which, until now, has been performed exclusively with manual micropipettes. This conventional injection has some deficiencies that include the variability in the aspiration/dispensing rates and inconstancy in the position of the pipette during injections, which can impair the measurements. Here we propose a new approach to improve the injection step in µTEDs by using electronic pipettes, which we named as automated injection. This novel injection mode overcomes the aforementioned disadvantages of manual injection. Electronic pipettes control aspiration and dispensing volumes/rates electronically and offer better ergonomics. We developed a new 3D-printed platform that allows to attach the electronic pipette to the µTED and always perform injections at a fixed position, increasing reproducibility of measurements. To demonstrate the practical applicability, this approach was first utilized for analysis of ferrous ion in pharmaceutical supplements and environmental samples. The method presented a wide linear range (0.7 to 200 μmolL–1), low limit of detection (0.21 μmolL–1), good accuracy (recoveries between 96 and 103 %) and excellent precision (relative standard deviation (RSD) ≤ 3.3 %). Thus, automated injection can be a great advance and change the state-of-the-art regarding µTEDs.

Developing an innovative 3D printing platform for production of personalised medicines in a hospital for the OPERA clinical trial

Breast cancer is the most frequently diagnosed cancer in women worldwide, and non-adherence to adjuvant hormonotherapy can negatively impact cancer recurrence and relapse. Non-adherence is associated with side effects of hormonotherapy. Pharmacological strategies to mitigate the side effects include coadministration of antidepressants, however patients remain non-adherent. The aim of this work was to develop medicines containing both hormonotherapy, tamoxifen (20 mg), along with anti-depressants, either venlafaxine (37.5 or 75 mg) or duloxetine (30 or 60 mg), to assess the acceptability and efficacy of this personalised approach for mitigating tamoxifen side effects in a clinical trial. A major criterion for the developed medicines was the production rate, specified at minimum 200 dosage units per hour to produce more than 40,000 units required for the clinical trial. A novel capsule filling approach enabled by the pharmaceutical 3D printer M3DIMAKER 2 was developed for this purpose. Firstly, semi-solid extrusion 3D printing enabled the filling of tamoxifen pharma-ink prepared according to French compounding regulation, followed by filling of commercial venlafaxine or duloxetine pellets enabled by the development of an innovative pellet dispensing printhead. The medicines were successfully developed and produced in the clinical pharmacy department of the cancer hospital Gustave Roussy, located in Paris, France. The developed medicines satisfied quality and production rate requirements and were stable for storage up to one year to cover the duration of the trial. This work demonstrates the feasibility of developing and producing combined tamoxifen medicines in a hospital setting through a pharmaceutical 3D printer to enable a clinical trial with a high medicines production rate requirement.

Engineered 3D-printed poly(vinyl alcohol) vascular grafts: Impact of thermal treatment and functionalization

Cardiovascular diseases, a leading cause of global mortality, are driving increased demand for artificial blood vessels for surgical repair. This study discloses the fabrication of three-dimensional (3D)-printed small blood vessels as tissue-engineered grafts. Large-diameter artery and vein grafts are readily available in the market, but small-diameter blood vessels face issues due to the lack of suitable materials. Lysine-biofunctionalized and unmodified poly(vinyl alcohol) grafts (PVA grafts) (2 mm inner diameter and 3 mm outer diameter) suitable for veins and venules were designed using Fusion 360 software, Autodesk Fusion. The PVA channels were fabricated from the 3D virtual model through fused deposition modeling using a PVA filament. These channels underwent thermal treatment to adjust their crystallinity, chemical crosslinking, and functionalization to optimize their mechanical properties and biocompatibility. Crosslinking and biofunctionalization were assessed using Fourier-transform infrared spectroscopy with attenuated total reflectance, while X-ray diffraction and differential scanning calorimetry were utilized for structural analysis. PVA grafts were biologically tested using three specific types of cell cultures: bEnd.3 brain endothelial cells, L929 fibroblast cells, and U937 monocyte-like cells. The hemocompatibility of the optimized vascular grafts was evaluated using horse blood, following the guidelines outlined in ASTM F756-13 Standard Practice for Assessment of Hemolytic Properties of Materials. The direct method for hemoglobin determination was specifically employed. Additionally, we developed an external polyethylene terephthalate glycol (PETG) 3D-printed platform to house the PVA grafts in parallel. The assembled platform (PETG and PVA graft) was connected to both an inlet and an outlet to facilitate the passage of an aqueous flow through the internal section of the PVA grafts during a flow test conducted under simulated body conditions (vacuum and blood pressure: 40 mbar). The flow was induced by a vacuum pump connected to the outlet of the platform, while the inlet was connected to a feeding glass. In summation, we have established a suitable protocol for producing small vascular grafts and demonstrated that the optimization process could significantly affect graft properties.

A 3D-printable gelatin/alginate/ε-poly-l-lysine hydrogel scaffold to enable porcine muscle stem cells expansion and differentiation for cultured meat development

The mass proliferation of seed cells and imitation of meat structures remain challenging for cell-cultured meat production. With excellent biocompatibility, high water content and porosity, hydrogels are frequently-studied materials for anchorage-dependent cell scaffolds in biotechnology applications. Herein, a scaffold based on gelatin/alginate/ε-Poly-l-lysine (GAL) hydrogel is developed for skeletal muscle cells, which has a great prospect in cell-cultured meat production. In this work, the hydrogel GAL-4:1, composed of gelatin (5 %, w/v), alginate (5 %, w/v) and ε-Poly-l-lysine (molar ratio vs. alginate: 4:1) is selected as cell scaffold based on Young's modulus of 11.29 ± 1.94 kPa, satisfactory shear-thinning property and suitable porous organized structure. The commercially available C2C12 mouse skeletal myoblasts and porcine muscle stem cells (PMuSCs), are cultured in the 3D-printed scaffold. The cells show strong ability of attachment, proliferation and differentiation after induction, showing high biocompatibility. Furthermore, the cellular bioprinting is performed with GAL-4:1 hydrogel and freshly extracted PMuSCs. The extracted PMuSCs exhibit high viability and display early myogenesis (desmin) on the 3D scaffold, suggesting the great potential of GAL hydrogel as 3D cellular constructs scaffolds. Overall, we develop a novel GAL hydrogel as a 3D-printed bioactive platform for cultured meat research.

Luminescent Supramolecular Metallogels: Drug Loading and Eu(III) as Structural Probe.

Supramolecular metallogels combine the rheological properties of gels with the color, magnetism, and other properties of metal ions. Lanthanide ions such as Eu(III) can be valuable components of metallogels due to their fascinating luminescence. In this work, we combine Eu(III) and iminodiacetic acid (IDA) into luminescent hydrogels. We investigate the tailoring of the rheological properties of these gels by changes in their metal:ligand ratio. Further, we use the highly sensitive Eu(III) luminescence to obtain information about the chemical structure of the materials. In special, we take advantage of computational calculations to employ an indirect method for structural elucidation, in which the simulated luminescent properties of candidate structures are matched to the experimental data. With this strategy, we can propose molecular structures for different EuIDA gels. We also explore the usage of these gels for the loading of bioactive molecules such as OXA, observing that its aldose reductase activity remains present in the gel. We envision that the findings from this work could inspire the development of luminescent hydrogels with tunable rheology for applications such as 3D printing and imaging-guided drug delivery platforms. Finally, Eu(III) emission-based structural elucidation could be a powerful tool in the characterization of advanced materials.