3D organoid model technologies have led to the development of innovative tools for cancer precision medicine. Yet, the gold standard culture system (Matrigel^®) lacks the ability for extensive biophysical manipulation needed to model various cancer microenvironments and has inherent batch-to-batch variability. Tunable hydrogel matrices provide enhanced capability for drug testing in breast cancer (BCa), by better mimicking key physicochemical characteristics of this disease’s extracellular matrix. Here, we encapsulated patient-derived breast cancer cells in bioprinted polyethylene glycol-derived hydrogels (PEG), functionalized with adhesion peptides (RGD, GFOGER and DYIGSR) and gelatin-derived hydrogels (gelatin methacryloyl; GelMA and thiolated-gelatin crosslinked with PEG-4MAL; GelSH). Within ranges of BCa stiffnesses (1–6 kPa), GelMA, GelSH and PEG-based hydrogels successfully supported the growth and organoid formation of HR+,−/HER2+,− primary cancer cells for at least 2–3 weeks, with superior organoid formation within the GelSH biomaterial (up to 268% growth after 15 days). BCa organoids responded to doxorubicin, EP31670 and paclitaxel treatments with increased IC₅₀ concentrations on organoids compared to 2D cultures, and highest IC₅₀ for organoids in GelSH. Cell viability after doxorubicin treatment (1 µM) remained >2-fold higher in the 3D gels compared to 2D and doxorubicin/paclitaxel (both 5 µM) were ~2.75–3-fold less potent in GelSH compared to PEG hydrogels. The data demonstrate the potential of hydrogel matrices as easy-to-use and effective preclinical tools for therapy assessment in patient-derived breast cancer organoids.

Extrusion-based bioprinting has gained widespread popularity in biofabrication due to its ability to assemble cells and biomaterials in precise patterns and form tissue-like constructs. To achieve this, bioinks must have rheological properties suitable for printing while maintaining cytocompatibility. However, many commonly used biomaterials do not meet the rheological requirements and therefore require modification for bioprinting applications. This study demonstrates the incorporation of Laponite-RD (LPN) into gelatin methacryloyl (GelMA) to produce highly customizable bioinks with desired rheological and mechanical properties for extrusion-based bioprinting. Bioink formulations were based on GelMA (5%–15% w/v) and LPN (0%–4% w/v), and a comprehensive rheological design was applied to evaluate key rheological properties necessary for extrusion-based bioprinting. The results showed that GelMA bioinks with LPN (1%–4% w/v) exhibited pronounced shear thinning and viscoelastic behavior, as well as improved thermal stability. Furthermore, a concentration window of 1%–2% (w/v) LPN to 5%–15% GelMA demonstrated enhanced rheological properties and printability required for extrusion-based bioprinting. Construct mechanical properties were highly tunable by varying polymer concentration and photocrosslinking parameters, with Young's moduli ranging from ∼0.2 to 75 kPa. Interestingly, at higher Laponite concentrations, GelMA cross-linking was inhibited, resulting in softer hydrogels. High viability of MCF-7 breast cancer cells was maintained in both free-swelling droplets and printed hydrogels, and metabolically active spheroids formed over 7 days of culture in all conditions. In summary, the addition of 1%–2% (w/v) LPN to gelatin-based bioinks significantly enhanced rheological properties and retained cell viability and proliferation, suggesting its suitability for extrusion-based bioprinting.

Basement membrane extracts (BME) derived from Engelbreth–Holm–Swarm (EHS) mouse sarcomas such as Matrigel^® remain the gold standard extracellular matrix (ECM) for three-dimensional (3D) cell culture in cancer research. Yet, BMEs suffer from substantial batch-to-batch variation, ill-defined composition, and lack the ability for physichochemical manipulation. Here, we developed a novel 3D cell culture system based on thiolated gelatin (Gel-SH), an inexpensive and highly controlled raw material capable of forming hydrogels with a high level of biophysical control and cell-instructive bioactivity. We demonstrate the successful thiolation of gelatin raw materials to enable rapid covalent crosslinking upon mixing with a synthetic poly(ethylene glycol) (PEG)-based crosslinker. The mechanical properties of the resulting gelatin-based hydrogels were readily tuned by varying precursor material concentrations, with Young’s moduli ranging from ~2.5 to 5.8 kPa. All hydrogels of varying stiffnesses supported the viability and proliferation of MDA-MB-231 and MCF-7 breast cancer cell lines for 14 and 21 days of cell culture, respectively. Additionally, the gelatin-based hydrogels supported the growth, viability, and osteogenic differentiation of patient-derived preosteoblasts over 28 days of culture. Collectively, our data demonstrate that gelatin-based biomaterials provide an inexpensive and tunable 3D cell culture platform that may overcome the limitations of traditional BMEs.

Decellularized extracellular matrix (dECM)‐based biomaterials mimic native ECM and support 3D cell culture. A photocrosslinkable porcine bone‐derived dECM hydrogel (dECM‐MA) is developed with tunable mechanical properties for tissue‐specific in vitro models. Trabecular bone is demineralized with 10% EDTA and decellularized via osmotic shock using 3.4 m NaCl, reducing DNA content by 94% while preserving key ECM proteins. Proteomic analysis identifies 81 matrisome proteins, with 76 shared between native and decellularized tissue. The dECM is solubilized by pepsin digestion and functionalized with methacryloyl groups, achieving 87–98% functionalization. Photocrosslinked dECM‐MA hydrogels shows tunable Young's moduli (0.5–120 kPa) depending on polymer concentration (0.25–2% w/v) and crosslinking duration (8–120 s). Primary human osteoblasts (hOBs) encapsulated in dECM‐MA (5, 10, and 20 kPa) remains viable and exhibits osteogenic morphology. In 10 kPa hydrogels, hOBs shows increased metabolic activity, elevated alkaline phosphatase, and mineral deposition (µCT, Alizarin Red). Expression of DMP‐1 and osteocalcin indicates cell maturation and ECM remodeling. This study demonstrates the feasibility of creating tunable, bone‐specific dECM hydrogels for 3D culture. dECM‐MA provides a controllable matrix environment and represents a versatile platform for disease modeling and drug screening in tissue‐specific microenvironments.

Decellularized extracellular matrices (dECMs) are promising biomaterials for generating tissue-specific in vitro models due to their organotypic extracellular matrix (ECM) protein profiles compared to natural and synthetic alternatives. However, most dECM-based hydrogels rely on collagen fibrillogenesis, resulting in limited mechanical tuneability and cell instructivity. Here, we developed LungMA, a photocrosslinkable, methacrylated lung dECM hydrogel engineered for precise stiffness modulation and tissue-specific lung cancer modelling. The decellularization process removed >99 % of native DNA, ensuring minimal cellular remnants while preserving key ECM components including laminin-332, collagen VI, and heparan sulfate proteoglycan 2 (HSPG2). Methacrylation and photoinitiation enabled formation of stable LungMA hydrogels with tunable stiffnesses ranging from 1 kPa (healthy lung) to 4 kPa (fibrotic lung).

Osteogenesis (bone formation) and vascularization (blood vessel formation) are two central and interconnected physiological-relevant processes in bone formation. Prevascularization of humanized tissue-engineered bone constructs (hTEBCs) has been proposed to better mimic the human bone microenvironment by enhancing vascular integration and facilitating greater osteogenic capacity. Here, we investigated the effects of premineralization and prevascularization on bone and vasculature development in an ectopic hTEBC model using a scaffold-hydrogel composite approach. Human osteoblast cells (hOBs) were cultured under osteogenic conditions (OM), with or without a 3-day mineralization boost (OM+) period for 4 weeks prior to implantation in vivo in a supporting porous polycaprolactone (mPCL) scaffold. Separately, photocrosslinkable fish gelatin-derived hydrogels placed within supporting mPCL scaffolds showed formation of elongated vascular networks as early as day 3 with in vitro coculture of human umbilical vein endothelial cells (HUVECs) and human bone marrow mesenchymal stem/stromal cells (MSCs). The OM and OM+ cultured constructs were subcutaneously implanted into immunocompromised rats with and without the prevascular hydrogels, resulting in four subgroups: OM, OM+, OM/Vas, and OM+/Vas. Our results demonstrated that the OM+ group led to more rapid osteoinduction and enhanced osteogenic differentiation in vivo with woven bone structure and active remodeling. Conversely, prevascularization (OM/Vas, OM+/Vas groups) led to reduce in vivo bone volume and density but promoted the development of human endothelial networks and successful anastomosis with host vasculature. Our study highlights the distinct contributions of premineralization and prevascularization, where premineralization is critical for robust bone formation and prevascularization enhances vascular integration, providing important insights for advancing the physiological relevance of hTEBC models in animal hosts. STATEMENT OF SIGNIFICANCE: This study demonstrates the development of humanized tissue engineered bone constructs incorporating a vascular niche using a rat. By integrating innovative pre-mineralization and pre-vascularization techniques within scaffold-hydrogel composite, we show that premineralization accelerates bone formation, while prevascularization promotes endothelial network formation and integration with host vasculature. Photocrosslinkable, low-stiffness LunaGel™ hydrogels enhanced microcapillary-like structure formation and endothelial sprouting in in vitro co-culture. However, by combining osteogenic and vascular cues within a biodegradable composite, this work advances the bone tissue engineering field by creating a model that more accurately reflects the divergent and competing nature of vascularization and bone formation. This platform has broad applicability for studying bone-vascular interactions and may inform strategies to improve the design of biomaterials for regenerative therapies.