Organoids hold great promise for modeling development, disease, and patient-specific therapy, but their translation is limited by poor vascularization, lack of immune and neural components, low reproducibility, and difficulties in scale-up. 3D bioprinting can address these bottlenecks by enabling digitally guided, spatially precise deposition of bioinks to construct multiscale architectures and perfusable channel networks, yet matching printing principles with material systems remains a central challenge. Unlike existing reviews that focus on isolated technologies or materials, this review introduces a cohesive paradigm that systematically links assembly mechanisms, material properties, and organoid functions along a mechanism–material–function axis. Its core breakthrough shifts the field from empirical guesswork to on-demand engineered design. We analyzed physicochemical mechanisms, such as ionic crosslinking, hydrophobic interactions, dynamic covalent bonding, and photoinitiated polymerization, and mapped them to tunable metrics, including modulus, degradation kinetics, mass-transport capacity, and bioactive delivery. Based on this mapping, we developed a full-chain decision framework for technology selection, material design, and process-parameter optimization, and proposed a predictive, reproducible formulation strategy. By transforming organoid fabrication from an empirical practice into an engineering discipline, this framework enables predictable and scalable organoid fabrication for regenerative medicine, drug discovery, and disease modeling applications through standardized process-parameter optimization and material recipe design.

The development of flexible and 3D‐printable surface-enhanced Raman scattering (SERS) substrates requires hydrogel architectures that support uniform nanoparticle distribution, structural robustness, and controlled filament formation. In this study, cellulose nanofibers (CNFs) and cellulose microfibers (CMFs) were incorporated into a poly(vinyl alcohol)/sodium alginate (PVA/SA) hydrogel crosslinked through borax to elucidate how fiber geometry, interfacial chemistry, and flow behavior collectively govern printability and plasmonic performance. CNFs form an interconnected and dynamically recoverable network that enhances viscosity, elastic recovery, and structural cohesion, enabling stable extrusion during 3D printing. The shear field within the printing nozzle further induces partial alignment of CNFs, generating more continuous microdomains that influence subsequent distribution of in situ grown gold nanoparticles (AuNPs). Spectroscopic and rheological analyses show that AuNP incorporation modulates local hydrogen bonding while preserving the dynamic borate crosslinking essential for filament fidelity. The 3D-printed CNF hydrogels exhibit clear and distinguishable SERS responses, with detectable rhodamine 6G (R6G) signals down to 10−6 M. This work provides a mechanistic understanding of how fiber morphology, flow-induced alignment, and nanoparticle-matrix interactions jointly define SERS behavior in printable hydrogels, offering a scalable design framework for next‐generation soft-material sensing platforms.

Bone and cartilage defects resulting from trauma, degenerative diseases, or congenital malformations remain a significant clinical challenge due to the limited intrinsic healing capacity of these tissues, often leading to unsatisfactory outcomes. Piezoelectric biomaterials, which are capable of generating localized electrical signals under mechanical stimulation, have attracted considerable attention as they could mimic the electromechanical microenvironment of native tissues and modulate key cellular processes. However, conventional fabrication strategies have usually failed to meet the personalized requirements of bone and cartilage regeneration. Three-dimensional (3D) printing offers powerful tools for producing patient-specific scaffolds with complex architectures and controlled functionality. In this review, we firstly introduce the piezoelectric properties of the natural bone and cartilage tissue, and then discuss the characteristics of piezoelectric materials in regenerative medicine, with particular emphasis on the advantages and limitations of using 3D printing techniques in the fabrication of the piezoelectric biomaterials. Finally, we summarize the recent advances in 3D-printed piezoelectric scaffolds for bone and cartilage regeneration. Consequently, this review highlights the significant potential and practical value of 3D-printed piezoelectric scaffolds as the next generation of osteochondral implants.  

Head and neck squamous cell carcinomas (HNSCCs) are aggressive malignancies with poor prognosis and limited therapeutic options. Electrochemotherapy (ECT), combining short electric pulses with chemotherapeutic agents to enhance intracellular drug uptake, has shown clinical potential but still requires physiologically relevant in vitro models for protocol optimization and mechanistic studies. Here, we introduce a three-dimensional 3D bioprinted in vitro HNSCC model specifically designed for the assessment of electroporation. Structures were fabricated using a composite hydrogel composed of 8% sodium alginate and 4% gelatin (w/w), crosslinked with calcium chloride at concentrations of 0.5%, 1%, and 2%. Uniaxial compression testing confirmed elastic moduli spanning the physiological tumor stiffness range, with the 1% calcium chloride formulation providing optimal mechanical and handling characteristics (42.96 ± 19.89 kPa). Hypopharyngeal carcinoma FaDu cells (5×106/mL) embedded in three-layer structures (thickness: 1.05 mm) maintained 75–80% viability for up to 21 days and formed tumor-like spheroids (mean diameter: 303 ± 113 μm), reflecting native tumor architecture. Electroporation with eight pulses at 200 V for 100 μs efficiently permeabilized the cell membrane, as evidenced by the internalization of propidium iodide, while maintaining high cell viability as confirmed by live/dead analysis. Programmed death-ligand 1 expression was preserved and upregulated in 3D spheroids compared to two-dimensional (2D) controls, supporting the platform’s relevance for immuno-oncology studies. Compared to other 3D HNSCC models, our system integrates mechanical tuning, electroporation compatibility, and immune-related biomarker expression, enabling functional validation of electric field-mediated intracellular delivery. This proof-of-concept platform demonstrates structural fidelity, long-term cell viability, and high reproducibility, offering a scalable, human-relevant tool for preclinical optimization of ECT and other electrically based therapies, bridging the gap between conventional 2D cultures and complex in vivo models.

Extrusion-based three-dimensional bioprinting remains limited by the absence of standardized methods to define the pressure conditions required for stable hydrogel flow. As a result, most workflows still rely on empirical tuning, which compromises reproducibility, structural fidelity, and interlaboratory comparability. Addressing this gap requires quantitative tools capable of identifying the minimum pressure for extrusion and the pressure range in which continuous, defect-free flow is maintained. This work presents a modular characterization platform integrating real-time pressure sensing, together with nozzle temperature regulation and environmental monitoring (temperature, humidity, and carbon dioxide) to ensure controlled and reproducible extrusion conditions. Using 10% gelatin methacryloyl, force–displacement curves revealed a stabilization pressure of 165 kPa, associated with continuous extrusion and minimal geometric deviation, and bounded by experimentally validated under-extrusion (155 kPa) and over-extrusion (185 kPa) conditions. Bioprinting tests confirmed that operating within this stabilization zone improves filament uniformity, print fidelity, and dimensional accuracy compared with under- and over-extrusion regimes. Quantitative metrics, including deflection analysis, printability parameter, void–area similarity, and structural similarity index, demonstrated superior reproducibility at the stabilization pressure. Biological validation using MCF-7 cells showed that 165 kPa preserved high viability (97.9%), whereas extrusion at 185 kPa reduced survival to 88.6%, confirming the sensitivity of cell integrity to excess shear stress. Together, these findings establish a sensor-driven calibration strategy that replaces trial-and-error parameter selection with quantitative and reproducible pre-print optimization. The device is compatible with commercial bioprinters and provides a practical framework for improving process standardization, structural fidelity, and biological safety in extrusion-based bioprinting. The platform is conceived as an independent, modular device for experimental calibration of extrusion parameters prior to bioprinting.

Tissue engineering (TE) holds significant potential for repairing osteochondral (OC) defects caused by trauma and degenerative diseases. However, the structural and functional heterogeneity between cartilage and bone imposes distinct requirements for regenerative outcomes, while stable integration of the OC interface remains a critical clinical hurdle. Three-dimensional (3D) printing technology, leveraging the advantages of personalized manufacturing and precise structural control, systematically optimizes the synergistic application of core TE elements (cells, growth factors, and scaffolds) during fabrication, offering advanced solutions for OC TE. By mimicking the biomechanics and the physiological regulatory mechanisms of native joints, 3D printing facilitates appropriate microenvironments across material, structural, and mechanical levels. Endowed with outstanding reasoning and predictive advantages, artificial intelligence (AI) has greatly advanced the development of 3D printing. In OC TE, AI exhibits promising applications throughout the 3D printing workflow, including printing process parameter regulation, ink evaluation, and scaffold design optimization. This paper systematically reviews OC TE’s general and region-specific requirements, followed by 3D printing’s innovative solutions and AI-assisted breakthroughs. Finally, we discuss the limitations and prospects of this interdisciplinary integration of 3D printing and AI in OC TE.

Three-dimensional (3D) bioprinting enables the fabrication of engineered tissues, but cell damage during printing and limitations in long-term preservation hinder practical applications. Traditional cryoprotectants, such as dimethyl sulfoxide (DMSO), introduce cytotoxicity and require complex removal, restricting immediate tissue usability. Here, we present an integrated extrusion-based bioprinting and DMSO-free antifreeze hydrogel strategy to produce cell-laden constructs with high post-thaw viability and proliferative capacity. Systematic optimization of bioink composition (6% L-proline with varying gelatin methacryloyl concentrations), extrusion parameters, and crosslinking conditions enabled high-fidelity scaffold fabrication while preserving cell viability and proliferation. Numerical simulations guided the maximum printable heights for fibers of different diameters, supporting construct scalability. Storing cell-laden 3D-printed scaffolds in cryovials at −80 °C effectively maintained high cell viability compared with alternative cooling protocols. Cells in 3D scaffolds exhibited superior post-thaw proliferation compared with two-dimensional culture, and the platform was validated using C2C12 myoblasts, achieving high survival and robust recovery of proliferative capacity. This study establishes a practical and versatile framework for integrating bioprinting and cryopreservation to support the generation of cell-laden constructs with preserved viability and structural integrity for regenerative medicine applications.

Bioprinting has emerged as a transformative technology in biofabrication, enabling the precise spatial arrangement of biomaterials, living cells, and bioactive factors to generate functional three-dimensional biological constructs. Recent advances are redefining the scope and impact of this field through innovations in both materials and methodologies. Multi-material and multiscale printing strategies are enhancing the ability to replicate the hierarchical architecture and functional gradients of native tissues, while the valorization of waste-derived biomaterials for bioink formulation is introducing sustainable solutions without compromising performance. The integration of bioprinting with organ-on-a-chip systems is providing highly sophisticated in vitro models for disease research and drug discovery, and in situ bioprinting techniques are opening new possibilities for direct, patient-specific tissue repair. Parallel to these developments, four-dimensional bioprinting introduces the dimension of time, allowing printed constructs to change shape, properties, or function in response to environmental stimuli. The application of artificial intelligence in process monitoring and quality control is improving reproducibility, predictive accuracy, and manufacturing efficiency, thus paving the way for standardized production. Looking ahead, the emerging concept of five-dimensional bioprinting— integrating spatial, temporal, and functional control—suggests a paradigm shift in the design and manufacturing of living systems. Collectively, these advances are broadening the technological capabilities of biofabrication and accelerating the translation of bioprinting from experimental settings toward transformative clinical and industrial applications. This review synthesizes current progress while outlining the opportunities and challenges that will shape the next generation of bioprinting technologies.

Glioblastoma (GBM) is an aggressive, World Health Organization grade 4 brain tumor with a poor prognosis, largely due to its complex, treatment-resistant microenvironment. To better model this environment for preclinical testing, we developed a three-dimensional (3D) biomimetic bioprinting platform using patient-derived GBM cells. Two hydrogels, alginate/gelatin (AlgGel; 1.5%/7.5%) and gelatin methacryloyl (10%), were evaluated for biocompatibility. GBM cells (GBM06, GBM14, and GBM15), transduced with iRFP-680 for viability tracking, were embedded in the hydrogels and printed. Tumor growth and viability were monitored for 28 days using fluorescence microscopy, complemented by electron microscopy (EM) for structural analysis. Drug response testing included temozolomide (TMZ; 10 μM) and the cyclin-dependent kinases 4/6 inhibitor abemaciclib (1 μM). Cell viability and extracellular vesicle (EV) release were quantified. Efficacy was further assessed in a co-culture with astrocytes. The AlgGel hydrogel supported superior long-term viability and growth. EM analysis of AlgGel scaffolds revealed preserved cellular architecture and adherence to the bioprinted extracellular matrix. Drug response assays confirmed findings previously observed in 2D and 3D cultures. Two cycles of abemaciclib reduced GBM cell viability in AlgGel scaffolds, accompanied by a significant decrease in EV secretion. TMZ, in contrast, did not significantly affect cell viability. The reduction in viability remained pronounced in co-culture with astrocytes, without compromising astrocyte viability. In this study, we present a  3D biomimetic bioprinting model that successfully mimics key aspects of the GBM microenvironment. This model demonstrates strong potential as a preclinical drug screening tool, enabling improved mechanistic insight into cell–matrix interactions that govern nutrient/metabolite diffusion and therapeutic responses.

The development of advanced hydrogel systems capable of precise three dimensional (3D) printing and controlled therapeutic delivery is critical for next generation biofabrication strategies. In this study, we present a laponite-reinforced gelatin methacryloyl (GelMA)/ionic liquid hydrogel engineered to simultaneously improve printability and sustained release of bioactive molecules. The incorporation of laponite nanoparticles markedly enhances rheological characteristics, including viscosity, shear-thinning behavior, and structural fidelity, facilitating high-resolution extrusion-based 3D printing. Specifically, the laponite concentration was limited to 1% w/v to preserve the soft mechanical environment (<3 kPa) essential for neural tissue while sufficiently improving rheological properties for processing. Beyond its mechanical and processing advantages, the hydrogel enables the prolonged release of retinoic acid and glial cell line-derived neurotrophic factor, promoting the proliferation and neuronal differentiation of N2A cells. This dual-functional platform demonstrates significant potential for the fabrication of complex, cell-instructive scaffolds, offering a versatile approach for applications where structural precision and localized drug delivery are essential.

Integrating stimuli-responsive nanoplatforms into 3D-printed scaffolds offers a sophisticated approach to mimicking the complex microenvironment of bone healing while minimizing the side effects associated with high-dose growth factor therapy. This study reports the design of a mesoporous silica-based dual-drug delivery system co-loaded with dexamethasone (DEX) and bone morphogenetic protein-2 (BMP-2) to harness their synergistic osteogenic potential while minimizing BMP-2-associated side effects. Mesoporous silica nanoparticles (MSNs) were synthesized to encapsulate DEX, followed by a polydopamine (PDA) coating formed via self-polymerization under mild alkaline conditions. BMP-2 was subsequently immobilized on the PDA layer, yielding pH-responsive DEX@MSNs/PDA/BMP-2 nanoparticles. Characterization confirmed uniform morphology, efficient loading, and controlled release, with accelerated release under acidic conditions, mimicking bone-defect environments. In vitro, dual-drug nanoparticles promoted osteogenic differentiation of preosteoblasts in a concentration-dependent manner, as evidenced by increased alkaline phosphatase activity, enhanced calcium deposition, and upregulated osteogenic genes. The nanoparticles were incorporated into three-dimensionally (3D)-printed polylactic acid/nano-hydroxyapatite scaffolds via freeze-drying, yielding composites with favorable porosity, mechanical properties, hydrophilicity, and biodegradability. In a rat calvarial defect model, implantation of the composite scaffolds significantly improved bone regeneration and neovascularization relative to controls, as demonstrated by micro-computed tomography and histological analyses. The results demonstrate that PDA-coated MSNs co-delivering DEX and BMP-2, integrated into 3D-printed scaffolds, provide a biocompatible and effective platform for bone tissue engineering. This approach combines pH-responsive release, dual-drug synergy, and structural support, offering translational potential for mandibular defect repair.

Nitrogen-doped carbon dots (NCDs) show promising potential in photodynamic antitumor applications due to their appropriate band gap and photo-responsiveness. Nevertheless, their therapeutic efficacy is limited by both a low reactive oxygen species (ROS) quantum yield and their propensity for aggregation. Herein, NCDs were encapsulated within mesoporous silica nanoparticles (MSNs) to fabricate an effective photosensitizer (NCDs@MSN) via a one-pot hydrothermal method. The covalent Si–C bonds formed between NCDs and MSNs enhanced interfacial charge transfer, thereby substantially amplifying the generation of ROS under hypoxic conditions. Meanwhile, the mesoporous structure of MSNs prevented NCD aggregation and provided a larger accessible surface area with more exposed active sites. Electron spin resonance spectroscopy confirmed the light-triggered generation of ROS, validating its potent ROS generation capacity under hypoxia. Subsequently, NCDs@ MSN were incorporated into poly-L-lactic acid to fabricate a composite scaffold via selective laser sintering, which was designed for postoperative photodynamic management of tumorous bone defects. The resulting scaffold exhibited potent photodynamic cytotoxicity against tumor cells alongside excellent biocompatibility. This work presents a potential strategy for engineering intelligent implants to prevent postoperative tumor recurrence.

Biodegradable polymers are widely used in bone tissue engineering to repair bone defects by providing biocompatible scaffolds with good mechanical support. Among them, three-dimensional (3D)-printed polycaprolactone (PCL) is commonly used due to its biocompatibility and compressive stability. However, its hydrophobicity and lack of osteogenic cues limit cell attachment and osteogenic differentiation. To address these limitations, 3D-printed PCL scaffolds were coated with polydopamine (PDA) to increase hydrophilicity, and milk-derived exosomes (EXOs) were immobilized on the surface to promote cell proliferation and induce osteogenic differentiation, thereby producing PDA–EXO scaffolds. EXOs represent a cell-free alternative for delivering growth factors and microRNA cargo that provide osteogenic cues for bone regeneration. PDA–EXO scaffolds demonstrated greater cell viability and proliferation compared to PCL and PDA scaffolds due to the synergistic effects of the PDA coating and the EXOs. The PDA–EXO scaffolds also led to better osteogenic differentiation compared to the other scaffolds. Taken together, these findings indicate that PDA enhanced surface hydrophilicity and that milk derived EXOs provided osteo inductive signals, thereby synergistically increasing cell proliferation and osteogenic differentiation while maintaining the scaffold’s mechanical properties. PDA–EXO functionalization, therefore, represents a practical, cell-free strategy to enhance PCL scaffolds for bone tissue engineering.

The tumor microenvironment (TME) is a major driver of osteosarcoma progression, metastasis, and therapeutic resistance, yet conventional models fail to effectively recapitulate the multicellular interactions and biomechanical cues of the bone niche. In this study, we developed a vascularized 3D-bioprinted osteosarcoma model using a biomimetic hydrogel composed of decellularized extracellular matrix, chondroitin sulfate, and hydroxyapatite. U2OS osteosarcoma cells, human mesenchymal stem cells (HMSCs), and human umbilical vein endothelial cells were co-cultured within the printed constructs. Confocal imaging, RNA sequencing, xenograft validation, and integration with clinical single-cell RNA-sequencing data were used to define TME-driven changes in tumor behavior. The engineered TME induced a proliferation-to-invasion switch characterized by G0/G1 arrest, reduced proliferation activity, and enhanced invasiveness, angiogenic potential, and extracellular-matrix remodeling. Transcriptomic profiling showed downregulation of cell-cycle programs, including E2F and MYC targets, together with activation of TGF-β signaling, epithelial–mesenchymal transition (EMT), and hypoxia-related pathways. Mechanistically, HMSCs were identified as key regulatory cells that promoted migratory programs in tumor cells, partly through CXCL chemokine signaling engaging CXCR2. The TME-induced state also conferred robust chemoresistance to paclitaxel, associated with cell-cycle quiescence and pro-survival signaling, such as NF-κB activation. Critically, the transcriptional signature of these quiescent-invasive cells closely mirrored that of a clinically observed osteosarcoma subpopulation with low proliferation and high EMT activity. This high-fidelity vascularized 3D-bioprinted model recapitulates major TME-dependent features of osteosarcoma and provides a biologically relevant platform for studying tumor plasticity and evaluating therapies targeting microenvironment-driven treatment resistance.

Bone tissue engineering has evolved from the passive use of structural fillers to a sophisticated discipline that actively harnesses endogenous regenerative mechanisms. At the core of this paradigm shift lies the immune system, particularly macrophages, as dynamic regulators of repair. Rather than merely suppressing inflammation, contemporary biomaterials are designed to modulate its trajectory, orchestrating the timely transition from a pro-inflammatory (M1) phenotype toward a pro-resolutive (M2) state. This review synthesizes a decade of progress in macrophage-centered bioengineering, focusing on strategies validated in preclinical in vivo models to ensure biological relevance and translational potential. These approaches are categorized across three levels of increasing complexity: (i) tailored biomaterials, where intrinsic physical and chemical properties direct cell fate; (ii) hybrid scaffolds, integrating diverse material classes and advanced delivery systems; and (iii) 3D-printed bioactive constructs, combining structural precision with ions, drugs, or cellular components. Together, these strategies define the emerging field of osteoimmunomodulation, characterized by the design of immuno-instructive materials. By critically evaluating the evolution of these principles, including their translational barriers and potential pitfalls, this review provides key insights into the field’s progression, identifying effective strategies to guide the development of next-generation bone therapies.

The osteochondral interface—characterized by a steep gradient in both composition and mechanical properties—remains one of the most challenging anatomical sites to regenerate. Reconstructing this spatially complex heterogeneity continues to confound conventional osteochondral grafts. Although multilayer scaffolds are widely adopted, interfacial delamination frequently compromises repair outcomes. Here, we report a self-healing, physically crosslinked silk fibroin–based 3D-printing ink that incorporates gelatin and nano-hydroxyapatite for the fabrication of bilayer scaffolds with robust interfacial bonding. By tuning ultrasonication time of silk fibroin and gelatin content, the ink exhibits exceptional printability and cytocompatibility, enabling >90% post-printing cell viability. Leveraging a dual-nozzle alternating-print strategy, we generated bilayer constructs that display a stable interface and layerspecific mechanical heterogeneity. Both upper- and lower-layer inks possess good self-healing capacity, eliminating delamination and yielding a monolithic scaffold. Functional analyses revealed significant upregulation of the chondrogenic marker type II collagen in the upper layer and the osteogenic marker RUNX2 in the lower layer, achieving bidirectional lineage instruction required for osteochondral regeneration. This silk/gelatin-based, physically crosslinked, integrative bilayer scaffold offers a promising therapeutic platform for osteochondral defect repair.

Three-dimensional (3D) printing holds great promise for creating patient-specific rehabilitative devices. While previous studies have demonstrated that behavioral interventions can induce cortical reorganization in stroke, direct evidence that a device alone—specifically, a patient-specific 3D-printed orthotic—can modulate brain function remains lacking. This proof-of-concept case series bridges this gap by integrating a complete digital workflow—from upper limb 3D scanning to stereolithography (SLA) fabrication of a custom hand orthotic—with longitudinal multimodal functional magnetic resonance imaging (fMRI) to assess cortical reorganization in chronic stroke. Four patients participated, with two index cases wearing the 3D-printed orthosis daily for four months alongside conventional rehabilitation, while two reference patients underwent conventional therapy only. Pre- and post-intervention neuroimaging revealed consistent, orthosis-associated neural changes: enhanced activity in the primary somatosensory cortex and greater functional integration within sensorimotor networks. Structural adaptations in motor regions were also observed in both index cases. Quantitatively, the index cases exhibited functional changes in nine brain regions and structural changes in six regions, substantially exceeding the minimal changes observed in the reference cases. This work provides the first direct evidence that a 3D-printed, patient-specific orthotic can drive targeted neuroplasticity independent of intensive behavioral coaching, validating its role not merely as a passive assistive device but as an active neuromodulatory tool. It establishes a translational framework for using objective neuroimaging biomarkers to guide the development and personalization of 3D-printed interventions in neurorehabilitation.

Neurogenic bladder (NB) after spinal cord injury (SCI) remains a major clinical challenge. Three-dimensional (3D) bioprinting technology offers a systematic solution in this field. This review summarizes its multidimensional applications in post-SCI NB. In basic research, the technology can be used to construct in vitro biomimetic “nerve-bladder” models for mechanism elucidation and high-throughput drug screening. In therapeutic strategies, it enables the fabrication of bioactive scaffolds that guide nerve regeneration and structurally biomimetic bladder tissues, synchronously promoting neural repair and tissue reconstruction. In clinical translation, image-based personalized 3D-printed models have been utilized for surgical planning and simulation. The integration of artificial intelligence further advances personalized design, printing process optimization, and multimodal collaborative research paradigms. Although major challenges remain in mechanistic understanding, manufacturing workflows, ethics, and regulation, 3D bioprinting may help shift NB management from “symptom management” to “functional reconstruction,” presenting tremendous and optimistic possibilities for transferring to the clinical end.

Monitoring metabolic flux in 3D tissue models is essential for validating physiological maturity and maintaining homeostatic balance. However, conventional optical based analytical techniques often fail to capture dynamic and transient metabolic shifts due to phototoxicity, signal attenuation in thick 3D constructs, and the requirement for invasive labeling, all of which hinder long-term, continuous monitoring. Standard assays such as high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) are also inherently time consuming and labor-intensive. Although electrochemical sensors offer a promising alternative, their integration into microfluidic platforms is frequently constrained by limited mass transport and the poor scalability of traditional lithography-based fabrication methods. Herein, we report an integrated, roughness-engineered microfluidic platform that addresses these limitations by strategically exploiting the “stair-stepping” artifacts inherent to fused deposition modeling (FDM) 3D printing as functional passive micromixers. By repurposing these manufacturing defects into deterministic micro-topographies, the platform induces chaotic advection,disrupting the boundary layer and enhancing solute exchange at physiologically relevant low flow rates. Numerical simulations elucidate the correlation between surface roughness and fluidic vorticity, providing a robust framework for performance optimization. Experimental validation demonstrates superior sensitivity, with a glucose response of 6.983 nA/mM and a lactate response of 5.669 nA/mM. Finally, real-time monitoring of biomimetic hydrogel phantoms over 500 min underscores the platform’s potential as a scalable and cost-effective quality control tool for 3D in vitro tissue engineering and regenerative medicine.

Treating critical-sized bone defects is a significant clinical challenge. Three-dimensional (3D) printing combined with bone tissue engineering (BTE) has emerged as a promising strategy for bone regeneration; however, key limitations persist, including a mismatch between scaffold degradation and osteogenesis, as well as insufficient bioactivity. In this study, we aimed to fabricate a hollow spherical mineralized biphasic calcium phosphate scaffold by 3D printing (photopolymerization via digital light processing) and incorporated within its cavity a 3D delivery system composed of methacryloyl-modified gelatin hydrogel loaded with bone marrow mesenchymal stem cells (BMSCs). The composite scaffold was systematically evaluated using material characterization, in vitro cytocompatibility analysis, and in vivo rabbit bone defect models. Our findings demonstrated that the scaffold exhibited favorable mechanical properties, biocompatibility, and enhanced osteogenic differentiation, migration, and pro-osteogenic gene expression in BMSCs. Notably, the scaffold effectively repaired critical-sized bone defects in rabbit models within 12 weeks. This novel BTE composite scaffold provides a groundbreaking design philosophy and an innovative therapeutic strategy for complex bone defect repair.

Serine/glycine-free (−SG) diets are recognized for boosting tumor immunotherapy efficacy by remodeling the tumor microenvironment, yet their clinical translation is hindered by aspiration risks and poor patient compliance associated with traditional liquid formulations. To address these challenges, this study leveraged 3D printing to transform −SG nutritional powder into a clinically viable semi-solid formulation. A functional food ink was developed by stabilizing −SG powder in a hydrocolloid matrix formed via electrostatic complexation between cationic chitosan and anionic xanthan gum. Formulation was optimized using response surface design of experiment methodology to maximize printability, with metabolic efficacy and biological safety validated in BALB/c mice, and clinical usability assessed in 20 cancer patients via sensory and direct swallowing tests. Rheological characterization confirmed that the polyelectrolyte network endowed the ink with ideal pseudoplasticity and yield stress—critical for extrusion-based 3D printing. The optimized formulation (1.25% chitosan, 1.25‰ xanthan gum) exhibited exceptional shape fidelity. In vivo studies showed the 3D-printed food for special medical purposes maintained serum serine/glycine depletion without systemic toxicity, supported by stable mouse body weight and normal liver/kidney function. Clinically, the 3D-printed semi-solid formulation significantly enhanced patient compliance, elevating sensory acceptability scores from “like slightly” to “like very much” (32.0 vs. 27.6, p < 0.0001). This study presents a novel application of 3D printing to fabricate texture-modified food for special medical purposes, effectively mitigating aspiration risks associated with traditional liquid amino acid-restricted diets.

Excessive inflammation remains a significant impediment to the regeneration of critical-sized bone defects, where the local immune microenvironment plays a crucial role in osteogenesis. However, most bone scaffolds primarily emphasize mechanical support and osteoconductivity, while their immunomodulatory potential remains largely unexplored. In this study, we designed and fabricated three-dimensional–printed hydroxyapatite/β-tricalcium phosphate/polycaprolactone (HTP) composite scaffolds to regulate macrophage polarization and promote bone regeneration. The HTP scaffolds demonstrated exceptional structural integrity and mechanical strength, facilitating the adhesion, proliferation, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells. Notably, the HTP scaffolds effectively modulated the immune microenvironment by inhibiting the polarization of pro-inflammatory M1 macrophages and promoting their transition toward the regenerative M2 phenotype. This immunomodulatory effect further enhanced osteogenic factor secretion, establishing a correlation between immunoregulation and osteogenesis. In a rat calvarial defect model, the HTP scaffolds significantly increased M2 macrophage infiltration, promoted angiogenesis, and accelerated new bone formation compared to other groups. This study demonstrates that three-dimensional–printed HTP composite scaffolds promote bone regeneration and angiogenesis by establishing a regenerative immune microenvironment, highlighting their potential as an advanced immunomodulatory platform for bone tissue engineering.

Today, organ building blocks (OBBs) serve as important tools for in vitro tissue modeling, personalized medicine, and regenerative approaches. Despite substantial advances in dental reconstruction methods, tissues of the oral cavity remain challenging to regenerate due to their complex structure and microenvironment. However, effective regeneration of the periodontal complex, e.g., in diseases such as periodontitis, persists, as current methods do not achieve complete tissue restoration. Cells from the gingiva and dental pulp are accessible sources of mesenchymal stem cells with high regenerative potential, making them promising materials for creating OBBs. These cells can serve as fundamental units for restoring the periodontal complex using techniques such as 3D bioprinting. This study aims to characterize and compare OBBs derived from gingival cells, pulp cells, and their combinations by assessing key parameters, including morphology, extracellular matrix composition, biomechanical properties, histology, and metabolic activity. Combining the two cell types improved the structural, mechanical, and functional properties of OBBs, making them more suitable for bioprinting than those derived from a single cell type. Moreover, all types of OBBs from the two cell cultures may be suitable as components of bioinks, depending on the specific purposes. The results provide insights into the potential use of these cell sources for tissue engineering and the development of personalized periodontal bio-constructs that may significantly improve treatment approaches for oral diseases.

For patients with fibrous dysplasia and severe “shepherd’s crook” deformity, total hip arthroplasty presents substantial challenges because of complex anatomy, pathological bone changes, and prosthesis instability. This study reports an integrated clinical pathway encompassing digital virtual planning, three-dimensional (3D) printing customization, and biomechanical evaluation. Using the Mimics software, patient computed tomography data were reconstructed, and a biplanar oblique osteotomy below the greater trochanter was simulated to correct the deformity. An individualized cementless long-stem prosthesis was designed based on the corrected medullary canal, followed by topology optimization and construction of a 70% porosity biomimetic porous structure to induce bone ingrowth. Finite element analysis under 1,800 N axial load and ±10 N•m torque showed peak stresses of 183.7 MPa in the femoral stem and 316.92 MPa in locking screws, both below material yield limits. Interface micromotion ranged from 0.21 mm to 0.48 mm, within the 0.5 mm threshold for promoting bone ingrowth, confirming the superior stability of the 3D-printed customized porous tantalum prosthesis system. Clinical follow-up of two patients demonstrated improved Harris Hip Scores, with one case showing a stable prosthesis position without loosening or subsidence at five years postoperatively. These findings support the potential value of precisely tailored 3D-printed prostheses in managing complex femoral deformities and pathological bone defects.

Digital light processing (DLP) is a widely adopted three-dimensional (3D) printing technology in dentistry that utilizes digital micromirror devices for photopolymerization. The quality of DLP-printed dental products depends on printing parameters. This review synthesizes how printing orientation, support design, layer thickness, exposure time, post-processing, and their interactions influence key quality attributes, including dimensional accuracy, mechanical properties, and efficiency, with the aim of proposing practice-oriented fabrication guidance for dental products. Among the evaluated parameters, printing orientation is particularly critical because its optimal selection depends on the geometry and clinical requirements of the specific clinical product. Printing orientation directly influences printing quality through critical surface orientation, model height, and interlayer cohesion area, and indirectly affects printing quality through other printing parameters. Current research is constrained by reliance on standard specimens and oversight of parameter interactions, necessitating the development of clinical scenario-specific printing workflows and material-oriented guidelines.

Bioprinting workflows often require repeated trial-and-error to achieve acceptable print quality, while relevant process knowledge and parameter ranges are dispersed across a rapidly growing literature. General-purpose language models can assist with scientific questions, but their output may be difficult to verify and can include unsupported claims. In this work, we present BioPrint-LKM, a bioprinting large knowledge model (LKM) implemented using a retrieval-augmented generation pipeline with citation grounding to provide traceable, evidence-based responses for bioprinting tasks. A curated knowledge base was constructed from 621 bioprinting papers, which were converted to text, segmented into passages, embedded into a vector index, and retrieved using exact nearest-neighbor similarity search. Retrieved passages were assembled into an augmented context and used to constrain generation under a domain prompt guideline that enforces source and page-level citation. The LKM was evaluated using 30 bioprinting-related questions and three large language model (LLM) backbones (GPT-4o, Claude-Sonnet-4.6, and Gemini-2.5-Flash). Across the tested 30-question benchmark, retrieval and citation grounding improved question-answer accuracy compared with LLM-only baselines by an average of 24.7%, particularly for queries requiring paper specific details such as component concentrations, mixing ratios, and instrument settings. A retrieval hyperparameter sweep further showed that top-k and passage length affect both evidence coverage and noise, with an intermediate passage length providing the best overall performance. Beyond knowledge retrieval, the LKM was applied to bioprinting process setup by generating initial parameter sets that were used to warm-start multi-objective Bayesian optimization toward target filament width and height. Compared with manual initialization, BioPrint-LKM-assisted initialization reduced the number of calibration trials by an average of 36.0% and supported downstream printing demonstrations, including conductive cell-laden hydrogel lines and an anatomical ear model. These results suggest that BioPrint-LKM, a citation grounded LKM, can serve as a practical lab-assistive tool to accelerate bioprinting setup and improve reproducibility.

Chronic diabetic wounds, characterized by persistent infection and impaired tissue regeneration, remain a formidable clinical challenge. In the present study, a 3D-bioprinted asymmetric bilayer scaffold was developed by integrating electrospinning and 3D bioprinting technologies to achieve anti-infective and pro-regenerative functions. The scaffold features a distinctive asymmetric architecture comprising a superficial layer (Layer S) and a basal layer (Layer B). Layer B, consisting of electrospun copper(I) oxide (Cu2O)–poly-ε-caprolactone nanofibers, serves as an effective antibacterial barrier specifically targeting methicillin-resistant Staphylococcus aureus (MRSA), while Layer S employs a 3D-bioprinted decellularized extracellular matrix hydrogel loaded with human bone marrow mesenchymal stem cell-derived extracellular vesicles (hBMSC-EVs) to facilitate tissue repair. Experimental results demonstrated that hBMSC-EVs significantly augmented fibroblast proliferation and migration, and the Cu2O-doped layer exhibited potent bactericidal activity against MRSA. In db/db diabetic mice, this asymmetric composite scaffold significantly accelerated wound closure compared to standalone treatments. Histological analysis further confirmed enhanced neovascularization and accelerated extracellular matrix reconstruction. Overall, this synergistic 3D-bioprinted bilayer system provides a high-performance strategy for the targeted management of MRSA-infected chronic diabetic wounds.