Bioprinting Research Articles

Advancing Cartilage Tissue Engineering: A Review of 3D Bioprinting Approaches and Bioink Properties.

Articular cartilage is crucial in human physiology, and its degeneration poses a significant public health challenge. While recent advancements in 3D bioprinting and tissue engineering show promise for cartilage regeneration, there remains a gap between research findings and clinical application. This review critically examines the mechanical and biological properties of hyaline cartilage, along with current 3D manufacturing methods and analysis techniques. Moreover, we provide a quantitative synthesis of bioink properties used in cartilage tissue engineering. After screening 181 initial works, 33 studies using extrusion bioprinting were analyzed and synthesized, presenting results that indicate the main materials, cells, and methods utilized for mechanical and biological evaluation. Altogether, this review motivates the standardization of mechanical analyses and biomaterial assessments of 3D bioprinted constructs to clarify their chondrogenic potential.

MAGIC matrices: freeform bioprinting materials to support complex and reproducible organoid morphogenesis.

Organoids are powerful models of tissue physiology, yet their applications remain limited due to their relatively simple morphology and high organoid-to-organoid structural variability. To address these limitations we developed a soft, composite yield-stress extracellular matrix that supports optimal organoid morphogenesis following freeform 3D bioprinting of cell slurries at tissue-like densities. The material is designed with two temperature regimes: at 4 °C it exhibits reversible yield-stress behavior to support long printing times without compromising cell viability. When transferred to cell culture at 37 °C, the material cross-links and exhibits similar viscoelasticity and plasticity to basement membrane extracts such as Matrigel. We first characterize the rheological properties of MAGIC matrices that optimize organoid morphogenesis, including low stiffness and high stress relaxation. Next, we combine this material with a custom piezoelectric printhead that allows more reproducible and robust self-organization from uniform and spatially organized tissue "seeds." We apply MAGIC matrix bioprinting for high-throughput generation of intestinal, mammary, vascular, salivary gland, and brain organoid arrays that are structurally similar to those grown in pure Matrigel, but exhibit dramatically improved homogeneity in organoid size, shape, maturation time, and efficiency of morphogenesis. The flexibility of this method and material enabled fabrication of fully 3D microphysiological systems, including perfusable organoid tubes that experience cyclic 3D strain in response to pressurization. Furthermore, the reproducibility of organoid structure increased the statistical power of a drug response assay by up to 8 orders-of-magnitude for a given number of comparisons. Combined, these advances lay the foundation for the efficient fabrication of complex tissue morphologies by canalizing their self-organization in both space and time.

3D bioprinting of fish skin-based gelatin methacryloyl (GelMA) bio-ink for use as a potential skin substitute.

Gelatin methacryloyl (GelMA), typically derived from mammalian sources, has recently emerged as an ideal bio-ink for three-dimensional (3D) bioprinting. Herein, we developed a fish skin-based GelMA bio-ink for the fabrication of a 3D GelMA skin substitute with a 3D bioprinter. Several concentrations of methacrylic acid anhydride were used to fabricate GelMA, in which their physical-mechanical properties were assessed. This fish skin-based GelMA bio-ink was loaded with human adipose tissue-derived mesenchymal stromal cells (ASCs) and human platelet lysate (HPL) and then printed to obtain 3D ASCs + HPL-loaded GelMA scaffolds. Cell viability test and a preliminary investigation of its effectiveness in promoting wound closure were evaluated in a critical-sized full thickness skin defect in a rat model. The cell viability results showed that the number of ASCs increased significantly within the 3D GelMA hydrogel scaffold, indicating its biocompatibility property. In vivo results demonstrated that ASCs + HPL-loaded GelMA scaffolds could delay wound contraction, markedly enhanced collagen deposition, and promoted the formation of new blood vessels, especially at the wound edge, compared to the untreated group. Therefore, this newly fish skin-based GelMA bio-ink developed in this study has the potential to be utilized for the printing of 3D GelMA skin substitutes.

Improvement of Mechanical Properties of 3D Bioprinted Structures through Cellular Overgrowth

The common use of hydrogel materials in 3D bioprinting techniques is dictated by the unique properties of hydrogel bioinks, among which some of the most important in terms of sustaining vital cell functions in vitro in 3D cultures are the ability to retain large amounts of liquid and the ability to modify rigidity and mechanical properties to reproduce the structure of the natural extracellular matrix. Due to their high biocompatibility, non-immunogenicity, and the possibility of optimizing rheological properties and bioactivity at the same time, one of the most commonly used hydrogel bioink compositions are polymer solutions based on sodium alginate and gelatin. In 3D bioprinting techniques, it is necessary for hydrogel printouts to feature an appropriate geometry to ensure proper metabolic activity of the cells contained inside the printouts. The desired solution is to obtain a thin-walled printout geometry, ensuring uniform nutrient availability and gas exchange during cultivation. Within this study’s framework, tubular bioprinted structures were developed based on sodium alginate and gelatin, containing cells of the immortalized fibroblast line NIH/3T3 in their structure. Directly after the 3D printing process, such structures are characterized by extremely low mechanical strength. The purpose of this study was to perform a comparative analysis of the viability and spreading ability of the biological material contained in the printouts during their incubation for a period of 8 weeks while monitoring the effect of cellular growth on changes in the mechanical properties of the tubular structures. The observations demonstrated that the cells contained in the 3D printouts reach the ability to grow and spread in the polymer matrix after 4 weeks of cultivation, leading to obtaining a homogeneous, interconnected cell network inside the hydrogel after 6 weeks of incubation. Analysis of the mechanical properties of the printouts indicates that with the increasing time of cultivation of the structures, the degree of their overgrowth by the biological material contained inside, and the progressive degradation of the polymer matrix process, the tensile strength of tubular 3D printouts varies.

Exploring the tunable micro-/macro-structure enabled by alginate-gelatin bioinks for tissue engineering

This study explores the development of optimized alginate-gelatin (AG) bioinks for advanced 3D bioprinting applications, particularly in tissue engineering. Central to our investigation is the establishment of a method for producing AG bioinks with highly tunable viscoelastic properties and the ability to create both macro- and micro-porous scaffolds through a liquid-liquid emulsion technique applied to chemically crosslinked hydrogels and shaped by microextrusion. Our methodology encompasses a comprehensive evaluation of homogenization, pasteurization techniques, and rheological assessments to optimize the mechanical properties of AG hydrogels, ensuring their suitability for bioprinting.The study demonstrates that dynamic homogenization and conventional pasteurization methods yield superior dissolution and sterility of the bioinks, crucial for maintaining optical quality and biological compatibility. Crosslinking optimization significantly enhanced the elasticity and reduced post-crosslinking shrinkage of the hydrogels, a key factor in achieving desired cell viability and function within the engineered tissues. The incorporation of porosity through a controlled liquid-liquid emulsion process was found to enhance cellular interactions and integration within the bioprinted constructs.Our findings confirm that the rheological properties of bioinks play a crucial role in determining bioprintability, with temperature modulation emerging as a key tool for tailoring these characteristics. The biocompatibility and functional performance of the AG hydrogels were validated through in vitro experiments, demonstrating promising cell viability and proliferation. This research lays the groundwork for the development of advanced bioinks capable of supporting complex tissue architectures in regenerative medicine and tissue engineering. By marrying the versatility of alginate and gelatin with innovative fabrication techniques, our study advances the frontier of 3D bioprinting, paving the way for the creation of biomimetic tissues with enhanced physiological relevance and therapeutic potential.

3D bioprinting of an intervertebral disc tissue analogue with a highly aligned annulus fibrosus via suspended layer additive manufacture.

Intervertebral disc (IVD) function is achieved through integration of its two component regions: the nucleus pulposus (NP) and the annulus fibrosus (AF). The NP is soft (0.3-5 kPa), gelatinous and populated by spherical NP cells in a polysaccharide-rich extracellular matrix (ECM). The AF is much stiffer (~100 kPa) and contains layers of elongated AF cells in an aligned, fibrous ECM. Degeneration of the disc is a common problem with age being a major risk factor. Progression of IVD degeneration leads to chronic pain and can result in permanent disability. The development of therapeutic solutions for IVD degeneration is impaired by a lack of in vitro models of the disc that are capable of replicating the fundamental structure and biology of the tissue. This study aims to investigate if a newly developed suspended hydrogel bioprinting system (termed SLAM) could be employed to fabricate IVD analogues with integrated structural and compositional features similar to native tissue. Bioprinted IVD analogues were fabricated to recapitulate structural, morphological and biological components present in the native tissue. The constructs replicated key structural components of native tissue with the presence of a central, polysaccharide-rich NP surrounded by organised, aligned collagen fibres in the AF. Cell tracking, actin and matrix staining demonstrated that embedded NP and AF cells exhibited morphologies and phenotypes analogous to what is observed in vivo with elongated, aligned AF cells and spherical NP cells that deposited HA into the surrounding environment. Critically, it was also observed that the NP and AF regions contained a defined cellular and material interface and segregated regions of the two cell types, thus mimicking the highly regulated structure of the IVD.

Zein-cyclodextrin complex used to prepare high internal phase pickering emulsions with various oil phases

Biobased solid particles for stabilizing high internal phase emulsions (HIPEs) are widely used in food and cosmetics industries. This study report a kind of zein-cyclodextrin complex particles which could HIPEs with various oil phases (log P values: 1.14–9.26), showcasing their wide applicability across different oil types. This versatility due to the slight differences (6–8°) in the three-phase contact angles for different oils. Furthermore, the complex particles showed a marked improvement in emulsification performance, as evidenced by their significantly higher diffusion rates (7–15 times faster) and reorientation speeds (2–5 times faster) at the oil-water interface. Moreover, the emulsions prepared were stable across a broad pH range (3–9), successfully addressing the common stability challenges associated with protein-based emulsifiers near their isoelectric points. Therefore, these complex particles have great potential in cosmetics, waste oil treatment and food field, such as multifunctional 3D bioprinting ink.

3D Bioprinting of Pig Macrophages and Human Cells Discovered the P2Y14 Receptor as a Mediator of Xenogenic Immune Responses

ABSTRACT Background The survival rate of pig lung xenotransplantation (PLXTx) recipients is severely limited by intense xenogenic immune responses, necessitating further insights into xenogeneic immunity and the development of models to study the PLXTx immune response. Methods We identified regulators of PLXTx immune response Using Gene ontology analysis. We assessed the metabolic changes and protein levels in 3D4/31 pig alveolar macrophages (PAMs) through flow cytometry and immunoblotting. To induce a xenogenic immune response, we co-cultured 3D4/31-PAMs with A549 human alveolar epithelial cells and evaluated cytokine expression using qRT-PCR. Results Gene ontology analysis identified STAT1 and alveolar macrophages as contributors to lung autoimmunity and transplant rejection. In 3D4/31-PAMs, phorbol myristate acetate-induced glycogen accumulation and cyclooxygenase-2 expression were inhibited by the P2Y14 inhibitor PPTN. Co-culturing 3D4/31-PAMs with A549 human alveolar epithelial cells via 3D bioprinting resulted in a more pronounced inflammatory response than 2D co-culture, with increased expression of genes related to the P2Y14 cascade and inflammation. This inflammatory gene expression was prevented by PPTN treatment. Conclusion Based on these results, we propose alginate bioprinting as an in vitro model for PLXTx and suggest that P2Y14 is a key regulator of xenogeneic immune responses in PAMs.

Emerging technologies in regenerative medicine: The future of wound care and therapy.

Wound healing, an intricate biological process, comprises orderly phases of simple biological processed including hemostasis, inflammation, angiogenesis, cell proliferation, and ECM remodeling. The regulation of the shift in these phases can be influenced by systemic or environmental conditions. Any untimely transitions between these phases can lead to chronic wounds and scarring, imposing a significant socio-economic burden on patients. Current treatment modalities are largely supportive in nature and primarily involve the prevention of infection and controlling inflammation. This often results in delayed healing and wound complications. Recent strides in regenerative medicine and tissue engineering offer innovative and patient-specific solutions. Mesenchymal stem cells (MSCs) and their secretome have gained specific prominence in this regard. Additionally, technologies like tissue nano-transfection enable in situ gene editing, a need-specific approach without the requirement of complex laboratory procedures. Innovating approaches like 3D bioprinting and ECM bioscaffolds also hold the potential to address wounds at the molecular and cellular levels. These regenerative approaches target common healing obstacles, such as hyper-inflammation thereby promoting self-recovery through crucial signaling pathway stimulation. The rationale of this review is to examine the benefits and limitations of both current and emerging technologies in wound care and to offer insights into potential advancements in the field. The shift towards such patient-centric therapies reflects a paradigmatic change in wound care strategies.

Effect of concentration and electrical charge of maltodextrin, and packing factor on electrospinning processing

The power law ηrel ∼ Ca of maltodextrins with higher entanglement concentrations (Ce) of dextrose equivalent (DE) 4, 10, and 18 exhibits an unusually high exponent a, ranging from 10.34 to 14.38 in congested solutions where particles occupy significant space. This contrasts with the dilute exponents (a ∼2) typically observed in polymer–solvent systems. To address this issue, several viscosity factors were evaluated using the Einstein–Roscoe and Mooney equations, which demonstrated viscosity dependence due to volume fraction (ϕ) > 0.35, shape, crowding factor (k) packing factor (1/k∼0.5) and centered cubic cell (CC), particularly for larger chain sizes (>20 glucoses) in DE-4. Chain electrical charges significantly stiffen the chain and increase its length beyond the theoretically predicted Kuhn persistent length (Lp), which seems to be responsible for the exponential increase in viscosity. Normalizing the viscosity/charge data revealed a log–log plot consistent with the exponent a of the general power law theory. In addition to concentration, electrospinning processing is influenced by strong particle–particle charge interactions, (ϕ), packing factor (1/k), CC, and chain sizes. The Maxwell model demonstrated poor interaction for DE-4 (modulus ∼286 Pa at maximum ϕ due to loose packing of CC, in contrast to DE-18, which exhibited a modulus of 994 Pa for a solution with maximum ϕ> 0.5 and a congested solution of 52% w/v, packing factor of 0.68, and high particle–particle interaction of the body-centered cubic (BCC) cell, favoring electrospun fiber formation. The packing factor, ϕ, and cell type, are highly sensitive and have potential applications in food systems, 3D bioprinting, among many other scientific domains.

Simultaneous processing of both handheld biomixing and biowriting of kombucha cultured pre-crosslinked nanocellulose bioink for regeneration of irregular and multi-layered tissue defects

The nanocellulosic pellicle derived from the symbiotic culture of bacteria and yeast (Kombucha SCOBY) is an important biomaterial for 3D bioprinting in tissue engineering. However, this nanocellulosic hydrogel has a highly entangled gel network. This needs to be partially modified to improve its processability and extrusion ability for its applications in the 3D bioprinting area. To control its mechanical and biological properties for direct 3D bioprinting applications, uniform reinforcement of nanocellulose-interacting polymers and nanoparticles in such a prefabricated gel network is essential. In this study, the hydrogel network is partially hydrolyzed with organic acid and subsequently transformed into a 3D bioprintable polyelectrolyte complex with chitosan and kaolin nanoparticles without any chemical crosslinker using a handheld 3D bioprinter. This handheld bioprinter ensures homogeneity in both biomixing and bioprinting of chitosan and kaolin within the modified nanocellulose network for multi-layered bioprinted scaffolds through an extensional shear mechanism. The biomixing simulation, mechanical (static, dynamic, and cyclic), 3D bioprinting, and cellular studies confirm the homogeneous biomixing of kaolin nanoparticles and live cells in this nanocellulose-chitosan polyelectrolyte hydrogel. The combination of SCOBY-derived nanocellulose-chitosan bioink with kaolin nanoparticles and a screw-driven handheld extrusion bioprinter demonstrates a promising platform for layer-by-layer regeneration of complex tissues with homogeneous cell/particle distribution with high cell viability.

Remote-Controlled Gene Delivery in Coaxial 3D-Bioprinted Constructs using Ultrasound-Responsive Bioinks

IntroductionCoaxial 3D bioprinting has advanced the formation of tissue constructs that recapitulate key architectures and biophysical parameters for in-vitro disease modeling and tissue-engineered therapies. Controlling gene expression within these structures is critical for modulating cell signaling and probing cell behavior. However, current transfection strategies are limited in spatiotemporal control because dense 3D scaffolds hinder diffusion of traditional vectors. To address this, we developed a coaxial extrusion 3D bioprinting technique using ultrasound-responsive gene delivery bioinks. These bioink materials incorporate echogenic microbubble gene delivery particles that upon ultrasound exposure can sonoporate cells within the construct, facilitating controllable transfection.MethodsPhospholipid-coated gas-core microbubbles were electrostatically coupled to reporter transgene plasmid payloads and incorporated into cell-laden alginate bioinks at varying particle concentrations. These bioinks were loaded into the coaxial nozzle core for extrusion bioprinting with CaCl2 crosslinker in the outer sheath. Resulting bioprints were exposed to 2.25 MHz focused ultrasound and evaluated for microbubble activation and subsequent DNA delivery and transgene expression.ResultsCoaxial printing parameters were established that preserved the stability of ultrasound-responsive gene delivery particles for at least 48 h in bioprinted alginate filaments while maintaining high cell viability. Successful sonoporation of embedded cells resulted in DNA delivery and robust ultrasound-controlled transgene expression. The number of transfected cells was modulated by varying the number of focused ultrasound pulses applied. The size region over which DNA was delivered was modulated by varying the concentration of microbubbles in the printed filaments.ConclusionsOur results present a successful coaxial 3D bioprinting technique designed to facilitate ultrasound-controlled gene delivery. This platform enables remote, spatiotemporally-defined genetic manipulation in coaxially bioprinted tissue constructs with important applications for disease modeling and regenerative medicine.

Novel 3D bioprinting approach for spinal cord injury repair using neural stem cells and TGF-β1 monoclonal antibody

ObjectiveTo investigate the repair of spinal cord injury (SCI) in rats using 3D bioprinted decellularized extracellular matrix (dECM) hydrogel, neural stem cells (NSCs), and TGF-β1 monoclonal antibody. MethodsThe spinal cord-derived dECM hydrogel (SC-dECM-gel) was optimized for 3D printing. Rheological tests established a 3 ​% concentration as optimal. In vitro tests assessed the effects of TGF-β1 monoclonal antibody on NSC viability and differentiation. A rat SCI model was treated with the printed gel, and recovery was monitored using the Basso-Beattie-Bresnahan test and evoked potentials. ResultsThe 3 ​% SC-dECM-gel showed superior rheological properties. TGF-β1 monoclonal antibody enhanced NSC survival and differentiation in vitro. In vivo, the 3D bioprinted gel significantly improved motor function and promoted neuronal regeneration. Conclusion3D bioprinted SC-dECM-gel loaded with NSCs and TGF-β1 monoclonal antibody effectively restores motor function and promotes regeneration in SCI rats, offering a promising approach for SCI treatment.

3D bioprinting meniscus tissue onboard the International Space Station

We bioprinted meniscus tissue on the International Space Station (ISS) using the onboard BioFabrication Facility (BFF). The three dimensional (3D) printing bioink, cells, culture media and fixative were delivered to the ISS on NG-18 and SpX-27 vehicles and stored prior to the printing operation. The meniscus tissue was fabricated from ink composed of collagens type I and II, chondroitin sulfate and mesenchymal stem cells. Following printing, the meniscus tissue was cultured for 2 weeks in growth media, then stored at 4 °C and returned to earth for analysis. The print showed good overall shape fidelity, and dimensions were comparable to control meniscus tissue printed on Earth. Young's modulus of the ISS printed meniscus was approximately 4-fold lower than the control. Histologic evaluation showed good cell distribution within the print. Though logistical challenges were encountered during payload delivery to the ISS and operational challenges limited the cell culture portion of this study, this investigation demonstrated the feasibility for 3D printed musculoskeletal tissue in microgravity. The completed meniscus tissue print is the largest tissue engineered model 3D printed on the ISS to date, the first to be 3D bioprinted using an ink similar in composition to native tissue, and the first to be fabricated on the ISS in an anatomically relevant shape. These experiments help advance the field of tissue engineering in low or microgravity where 3D bioprinting may have a role in future long term space flight or extraterrestrial habitation.

Double-crosslinked dECM bioink to print a self-sustaining 3D multi-layered aortic-like construct

Cardiovascular disease is the leading cause of death worldwide, with related mortality increasing from 12.1 million to 18.6 million in the past 30 years.To address the supply limitation of autologous vascular grafts and overcome the limits of current treatment options, 3D bioprinting techniques have been investigated.This study aimed at introducing a self-supporting and multi-layered 3D bioprinted construct as a promising alternative for large-blood vessel replacement. To this end, we developed an alginate-gelatin bioink enriched with decellularized extracellular matrix (dECM) of porcine aorta combined with a two-step crosslinking process. We investigated the feasibility of achieving structural stability and shape fidelity of the bioprinted construct over time through rheological characterization, printability tests, and degradation tests.According to the results of rheology and printability tests, dECM-enriched bioink combined with the double-crosslinking process (internal and external crosslink) showed good printability and high shape fidelity, withstanding more than 35 layers without the need for support. Moreover, the bioprinted construct preserved its structural stability over time, retaining a wall thickness comparable to that of the native aorta. Finally, immortalized mouse fibroblasts embedded in the bioink were well adhered to the bioink and alive over time. The double-crosslinked bioink represents an impactful strategy to produce an alternative conduit with the native hierarchical structure of the large blood vessels.

Bioprinting of Cells, Organoids and Organs-on-a-Chip Together with Hydrogels Improves Structural and Mechanical Cues.

The 3D bioprinting technique has made enormous progress in tissue engineering, regenerative medicine and research into diseases such as cancer. Apart from individual cells, a collection of cells, such as organoids, can be printed in combination with various hydrogels. It can be hypothesized that 3D bioprinting will even become a promising tool for mechanobiological analyses of cells, organoids and their matrix environments in highly defined and precisely structured 3D environments, in which the mechanical properties of the cell environment can be individually adjusted. Mechanical obstacles or bead markers can be integrated into bioprinted samples to analyze mechanical deformations and forces within these bioprinted constructs, such as 3D organoids, and to perform biophysical analysis in complex 3D systems, which are still not standard techniques. The review highlights the advances of 3D and 4D printing technologies in integrating mechanobiological cues so that the next step will be a detailed analysis of key future biophysical research directions in organoid generation for the development of disease model systems, tissue regeneration and drug testing from a biophysical perspective. Finally, the review highlights the combination of bioprinted hydrogels, such as pure natural or synthetic hydrogels and mixtures, with organoids, organoid-cell co-cultures, organ-on-a-chip systems and organoid-organ-on-a chip combinations and introduces the use of assembloids to determine the mutual interactions of different cell types and cell-matrix interferences in specific biological and mechanical environments.

Regenerative Medicine Approaches for Skin Wound Healing: from Allografts to Engineered Skin Substitutes

Abstract Purpose of the Review Recent advancements in tissue engineering and regenerative medicine have paved the way for innovative solutions in skin regeneration, particularly for extensive burns and full-thickness wounds where traditional approaches are limited. The purpose of the review is to explore the integration of bioactive materials, stem cell therapies, and tissue-engineered skin substitutes and their role in revolutionizing wound healing and skin transplantation. Recent Findings Studies leveraging natural and synthetic biomaterials as scaffolds, alongside the regenerative capabilities of mesenchymal stem cells (MSCs) and other cellular therapies, underscore the potential to enhance tissue repair, minimize scarring, and improve overall clinical outcomes. The development of multifunctional biomaterials and the advent of cutting-edge techniques such as 3D bioprinting and nanomedicine further propel the field, offering personalized and effective solutions. As these technologies evolve, they hold promise for more efficient, patient-specific skin grafting, reducing the need for systemic immunosuppression and enhancing graft survival. Summary The critical advancements in biomaterials, stem cell therapies, and tissue engineering, outline a course toward more effective and personalized skin regeneration therapies.

Biobased hydrogel bioinks of pectin, nanocellulose and lysozyme nanofibrils for the bioprinting of A375 melanoma cell-laden 3D in vitro platforms

Melanoma is one of the most aggressive types of skin cancer, and the need for advanced platforms to study this disease and to develop new treatments is rising. 3D bioprinted tumor models are emerging as advanced tools to tackle these needs, with the design of adequate bioinks being a fundamental step to address this challenging process. Thus, this work explores the synergy between two biobased nanofibers, nanofibrillated cellulose (NFC) and lysozyme nanofibrils (LNFs), to create pectin nanocomposite hydrogel bioinks for the 3D bioprinting of A375 melanoma cell-laden living constructs. The incorporation of LNFs (5, 10 or 15 wt%) on a Pectin-NFC suspension originates inks with enhanced rheological properties (shear viscosity and yield point) and proper shear-thinning behavior. The crosslinked hydrogels mimic the stiffness of melanoma, being stable under physiological and cell-culture conditions, and non-cytotoxic towards A375 melanoma cells. P-NFC-LNFs (10 %) reveals good printability (Pr = 0.89) and printing accuracy (51 ± 2 %), and when loaded with A375 cells (3 × 106 cells mL−1) the bioink originates 3D-constructs with high cell viability (92 ± 1 %) after 14 days. The potential of the constructs as in vitro models is corroborated by a drug-screening test with doxorubicin, where cells within the model displayed high sensitivity to the drug.

Fabrication of GelMA - Agarose Based 3D Bioprinted Photocurable Hydrogel with In Vitro Cytocompatibility and Cells Mirroring Natural Keratocytes for Corneal Stromal Regeneration.

The complex anatomy of the cornea and the subsequent keratocyte-fibroblast transition have always made corneal stromal regeneration difficult. Recently, 3D printing has received considerable attentionin terms of fabrication of scaffoldswith precise dimension and pattern. In the current work, 3D printable polymer hydrogels made of GelMA/agarose are formulated and its rheological properties are evaluated. Despite the variation in agarose content, both the hydrogels exhibited G'>G'' modulus. A prototype for 3D stromal model is created using Solid Works software, mimicking the anatomy of an adult cornea. The fabrication of 3D-printed hydrogels is performed using pneumatic extrusion. The FTIR analysis speculated that the hydrogel is well crosslinked and established strong hydrogen bonding with each other, thus contributing to improved thermal and structural stability. The MTT analysis revealed a higher rate of cell proliferation on the hydrogels. The optical analysis carried out on the 14th day of incubation revealed that the hydrogels exhibit transparency matching with natural corneal stromal tissue. Specific protein marker expression confirmed the keratocyte phenotype and showed that the cells do not undergo terminal differentiation into stromal fibroblasts. The findings of this work point to the potential of GelMA/A hydrogels as a novel biomaterial for corneal stromal tissue engineering.

Three-dimensional bioprinted materials in alginate-hyaluronic acid complex based hydrogel based bio-ink as absorbents for heavy metal ions removal

Major environmental and health effects arise from the presence of heavy metals in water, including lead (Pb²⁺), mercury (Hg²⁺), chromium (Cr⁶⁺), cadmium (Cd²⁺), and arsenic (As³⁺), which contribute significantly to water pollution and pose severe risks to ecosystems and human health. This study demonstrates the fabrication of 3D printed self-regenerative functional living materials, a fungi, by using mixture of sodium alginate and hyaluronic acid hydrogel as absorbents to remove the heavy metals from the environment. Bioprinting has emerged as a transformative technology for fabricating complex biological constructs. The bioprinting experiments, conducted with optimized parameters, revealed the viscoelastic behavior of the hydrogel, suitable for 3D bioprinting applications. MicroCT analysis indicated that the hydrogel's porosity and structural properties support fungal growth in a controlled three-dimensional setting. Microscopic analyses, including phase contrast microscopy, FESEM, and HRTEM, provided insights into the cellular morphology of the bioprinted constructs. Cell viability was assessed using flow cytometry with FDA and PI staining, showing a significant population of live cells, affirming the biocompatibility of the hydrogel. Additionally, the study explored the hydrogel's potential for heavy metal removal from water samples. Multi-element standard solutions containing Copper(Cu²⁺), Cadmium(Cd²⁺), Nickel(Ni²⁺), Cobalt(Co²⁺), and Ferrous(Fe³⁺) ions at different concentrations were incubated with hydrogel patches embedded with Aspergillus flavus. Atomic absorption spectrophotometry analysis showed rapid initial removal rates of metal ions, with maximum removal efficiency achieved around the 12th hour. Comparisons with a control hydrogel without the fungal strain demonstrated significantly enhanced removal efficiency due to the presence of Aspergillus flavus. This study highlights the dual functionality of sodium alginate with hyaluronic acid -based hydrogels for bioprinting fungi and for environmental remediation of heavy metals, offering promising applications in environmental cleanup.