Embedded Bioprinting of Breast Tumor Cells and Organoids Using Low-Concentration Collagen-Based Bioinks

Multi-Nozzles 3D Bioprinting Collagen/Thermoplastic Elasto-Mer Scaffold with Interconnect Pores

Scaffolds play a crucial role in tissue engineering as regenerative templates. Fabricating scaffolds with good biocompatibility and appropriate mechanical properties remains a major challenge in this field. This study proposes a method for preparing multi-material scaffolds, enabling the 3D printing of collagen and thermoplastic elastomers at room temperature. Addressing the previous challenges such as the poor printability of pure collagen and the difficulty of maintaining structural integrity during multilayer printing, this research improved the printability of collagen by optimizing its concentration and pH value and completed the large-span printing of thermoplastic elastomer using a precise temperature-control system. The developed hybrid scaffold has an interconnected porous structure, which can support the adhesion and proliferation of fibroblasts. The scaffolds were further treated with different post-treatment methods, and it was proven that the neutralized and cross-linked collagen scaffold, which has both nano-fibers and a certain rigidity, can better support the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The research results show that the collagen thermoplastic elastomer hybrid scaffold has significant clinical application potential in soft tissue and hard tissue regeneration, providing a versatile solution to meet the diverse needs of tissue engineering.

Vascularised organoids: Recent advances and applications in cancer research

Organoids are three-dimensional (3D) cellular models designed to replicate human tissues and organs while preserving their physiological complexity and functionality. Among these, vascularised organoids represent a groundbreaking advancement in 3D tissue engineering, incorporating vascular networks into engineered tissues to more accurately mimic the in vivo tumour microenvironment. These models offer significantly improved physiological relevance compared to conventional two-dimensional cultures or animal models, positioning them as invaluable tools in cancer research. Despite their potential, the rapid proliferation of techniques and materials for developing vascularised organoids presents challenges for researchers navigating this dynamic field. This systematic review provides a comprehensive examination of methodologies for fabricating vascularised organoids, with a focus on strategies that enhance vascularisation and support organoid growth. It critically evaluates the materials used, emphasising those that effectively mimic the extracellular matrix and facilitate vascular network formation. Key advancements in engineered organoids models are highlighted, emphasising their potential for studying interactions between vasculature and cancer cells, conducting drug screening, and understanding cytokine regulation. In summary, this review provides an in-depth overview of the current landscape of vascularised organoid fabrication and functionality, addressing challenges and opportunities within the field. A detailed understanding of the scope and future trajectories is essential for advancing organoid development and expanding their applications in both basic cancer research and clinical practice. KEY POINTS: Comparative analysis: Evaluation of organoids, animal models, and 2D models, highlighting their respective strengths and limitations in replicating physiological conditions and studying disease processes. Vascularisation techniques: Comparative evaluation of vascularised organoid fabrication methods, emphasising their efficiency, scalability and ability to replicate physiological vascular networks. Material selection: Thorough evaluation of materials for vascularised organoid culture system, focusing on those that effectively mimic the extracellular matrix and support vascular network formation. Applications: Overview of organoid applications in basic cancer research and clinical settings, with an emphasis on their potential in drug discovery, disease modelling and exploring complex biological processes.

Personalized Vascularized Tumor Organoid-on-a-Chip for Tumor Metastasis and Therapeutic Targeting Assessment

While tumor organoids have revolutionized cancer research by recapitulating the cellular architecture and behaviors of real tumors in vitro, their lack of functional vasculature hinders their attainment of full physiological capabilities. Current efforts to vascularize organoids are struggling to achieve well-defined vascular networks, mimicking the intricate hierarchy observed in vivo, which restricts the physiological relevance particularly for studying tumor progression and response to therapies targeting the tumor vasculature. An innovative vascularized patient-derived tumor organoids (PDTOs)-on-a-chip with hierarchical, tumor-specific microvasculature is presented, providing a versatile platform to explore tumor-vascular dynamics and antivascular drug efficacy. It is found that highly metastatic tumor cells induced vessel angiogenesis and simultaneously migrated toward blood vessels via the Notch pathway. The evident association between the angiogenic and migratory capacities of PDTOs and their clinical metastatic outcomes underscores the potential of the innovative platform for evaluating tumor metastasis, thus offering valuable insights for clinical decision-making. Ultimately, the system represents a promising avenue for advancing the understanding of tumor metastasis and developing personalized treatment strategies based on patient-specific tumor characteristics.

Strategies to overcome the limitations of current organoid technology - engineered organoids

Organoids, as 3D in vitro models derived from stem cells, have unparalleled advantages over traditional cell and animal models for studying organogenesis, disease mechanisms, drug screening, and personalized diagnosis and treatment. Despite the tremendous progress made in organoid technology, the translational application of organoids still presents enormous challenges due to the complex structure and function of human organs. In this review, the limitations of the translational application of traditional organoid technologies are first described. Next, we explore ways to address many of the limitations of traditional organoid cultures by engineering various dimensions of organoid systems. Finally, we discuss future directions in the field, including potential roles in drug screening, simulated microphysiology system and personalized diagnosis and treatment. We hope that this review inspires future research into organoids and microphysiology system.

Integrating 3D Bioprinting and Organoids to Better Recapitulate the Complexity of Cellular Microenvironments for Tissue Engineering

Organoids, with their capacity to mimic the structures and functions of human organs, have gained significant attention for simulating human pathophysiology and have been extensively investigated in the recent past. Additionally, 3D bioprinting, as an emerging bio-additive manufacturing technology, offers the potential for constructing heterogeneous cellular microenvironments, thereby promoting advancements in organoid research. In this review, the latest developments in 3D bioprinting technologies aimed at enhancing organoid engineering are introduced. The commonly used bioprinting methods and materials for organoids, with a particular emphasis on the potential advantages of combining 3D bioprinting with organoids are summarized. These advantages include achieving high cell concentrations to form large cellular aggregates, precise deposition of building blocks to create organoids with complex structures and functions, and automation and high throughput to ensure reproducibility and standardization in organoid culture. Furthermore, this review provides an overview of relevant studies from recent years and discusses the current limitations and prospects for future development.

Embedded Bioprinting of Breast Cancer-Adipose Composite Tissue Model for Patient-Specific Paracrine Interaction Analysis

The interaction between breast cancer and stromal tissues varies significantly from patient to patient, greatly impacting cancer prognosis. However, conventional models struggle to accurately replicate these patient-specific interactions. Herein, a novel breast cancer-adipose composite tissue model capable of precisely adjusting the inter-tissue interaction is developed. The composite tissue model is produced through precise embedded bioprinting of breast-cancer spheroids and live-adipose-tissue ink. This model possessed not only precisely patterned cancer spheroids but also well-preserved intrinsic extracellular matrices (ECMs) and heterogeneous cell populations of adipose tissue (AT). Evaluation results successfully demonstrated that the bioprinted composite model can precisely regulate adipokine secretion, drug resistance, and cancer-cell invasion characteristics by adjusting the distance between the cancer spheroids and adipose tissue. The utility of the model is validated using adipokine-targeted therapies (C-compound/SC600125 (SC), AG 490 (AG), and Metformin (MET)). Interestingly, the inhibition of cancer cell proliferation and invasion by these adipokine-targeted drugs nearly doubled as the tissue distance decreased. This suggests that the efficacy of the drugs can be precisely evaluated using the new model. These findings underscore the potential of the developed composite model to replicate patient-specific crosstalk, thereby offering a promising platform for the sophisticated evaluation of various breast-cancer therapies.

Exploration of organoids in ovarian cancer: From basic research to clinical translation

Ovarian cancer is a highly heterogeneous tumor with a poor prognosis. The lack of reliable and efficient research models that can accurately mimic heterogeneity has impeded in-depth investigations and hindered the clinical translation of research findings in ovarian cancer. Organoid models have emerged as a promising in vitro approach, demonstrating remarkable fidelity to the histological, molecular, genomic, and transcriptomic features of their tissues of origin. In recent years, organoids have contributed to advancing our understanding of ovarian cancer initiation, metastasis, and drug resistance mechanisms, as well as facilitating clinical screening of effective therapeutic agents. The establishment of high-throughput organoid culture systems, coupled with cutting-edge technologies such as organ-on-a-chip, genetic engineering, and 3D printing, has tremendous potential for accelerating ovarian cancer research translation. In this review, we present a comprehensive overview of the latest exploration of organoids in basic ovarian cancer research and clinical translation. Furthermore, we discuss the prospects and challenges associated with the use of organoids and related novel technologies in the context of ovarian cancer. This review provides insights into the application of organoids in ovarian cancer.

Organoid models of breast cancer in precision medicine and translational research

One of the most famous and heterogeneous cancers worldwide is breast cancer (BC). Owing to differences in the gene expression profiles and clinical features of distinct BC subtypes, different treatments are prescribed for patients. However, even with more thorough pathological evaluations of tumors than in the past, available treatments do not perform equally well for all individuals. Precision medicine is a new approach that considers the effects of patients' genes, lifestyle, and environment to choose the right treatment for an individual patient. As a powerful tool, the organoid culture system can maintain the morphological and genetic characteristics of patients' tumors. Evidence also shows that organoids have high predictive value for patient treatment. In this review, a variety of BC studies performed on organoid culture systems are evaluated. Additionally, the potential of using organoid models in BC translational research, especially in immunotherapy, drug screening, and precision medicine, has been reported.

Advancing cancer research through organoid technology

The complexity of tumors and the challenges associated with treatment often stem from the limitations of existing models in accurately replicating authentic tumors. Recently, organoid technology has emerged as an innovative platform for tumor research. This bioengineering approach enables researchers to simulate, in vitro, the interactions between tumors and their microenvironment, thereby enhancing the intricate interplay between tumor cells and their surroundings. Organoids also integrate multidimensional data, providing a novel paradigm for understanding tumor development and progression while facilitating precision therapy. Furthermore, advancements in imaging and genetic editing techniques have significantly augmented the potential of organoids in tumor research. This review explores the application of organoid technology for more precise tumor simulations and its specific contributions to cancer research advancements. Additionally, we discuss the challenges and evolving trends in developing comprehensive tumor models utilizing organoid technology.

Bioprinted, spatially defined breast tumor microenvironment models of intratumoral heterogeneity and drug resistance

Cellular, extracellular matrix (ECM), and spatial heterogeneity of tumor microenvironments (TMEs) regulate disease progression and treatment efficacy. Developing in vitro models that recapitulate the TME promises to accelerate studies of tumor biology and identify new targets for therapy. Here, we used extrusion-based, multi-nozzle 3D bioprinting to spatially pattern triple-negative MDA-MB-231 breast cancer cells, endothelial cells (ECs), and human mammary cancer-associated fibroblasts (HMCAFs) with biomimetic ECM inks. Bioprinted models captured key features of the spatial architecture of human breast tumors, including varying-sized dense regions of cancer cells and surrounding microvessel-rich stroma. Angiogenesis and ECM stiffening occurred in the stromal area but not the cancer cell-rich (CCR) regions, mimicking pathological changes in patient samples. Transcriptomic analyses revealed upregulation of angiogenesis-related and ECM remodeling-related signatures in the stroma region and identified potential ligand-receptor (LR) mediators of these processes. Breast cancer cells in distinct parts of the bioprinted TME showed differing sensitivities to chemotherapy, highlighting environmentally mediated drug resistance. In summary, our 3D-bioprinted tumor model will act as a platform to discover integrated functions of the TME in cancer biology and therapy.

The Use of Patient-Derived Organoids in the Study of Molecular Metabolic Adaptation in Breast Cancer

Around 13% of women will likely develop breast cancer during their lifetime. Advances in cancer metabolism research have identified a range of metabolic reprogramming events, such as altered glucose and amino acid uptake, increased reliance on glycolysis, and interactions with the tumor microenvironment (TME), all of which present new opportunities for targeted therapies. However, studying these metabolic networks is challenging in traditional 2D cell cultures, which often fail to replicate the three-dimensional architecture and dynamic interactions of real tumors. To address this, organoid models have emerged as powerful tools. Tumor organoids are 3D cultures, often derived from patient tissue, that more accurately mimic the structural and functional properties of actual tumor tissues in vivo, offering a more realistic model for investigating cancer metabolism. This review explores the unique metabolic adaptations of breast cancer and discusses how organoid models can provide deeper insights into these processes. We evaluate the most advanced tools for studying cancer metabolism in three-dimensional culture models, including optical metabolic imaging (OMI), matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), and recent advances in conventional techniques applied to 3D cultures. Finally, we explore the progress made in identifying and targeting potential therapeutic targets in breast cancer metabolism.

Extracellular matrix regulation of cell spheroid invasion in a 3D bioprinted solid tumor-on-a-chip

Tumor organoids and tumors-on-chips can be built by placing patient-derived cells within an engineered extracellular matrix (ECM) for personalized medicine. The engineered ECM influences the tumor response, and understanding the ECM-tumor relationship accelerates translating tumors-on-chips into drug discovery and development. In this work, we tuned the physical and structural characteristics of ECM in a 3D bioprinted soft-tissue sarcoma microtissue. We formed cell spheroids at a controlled size and encapsulated them into our gelatin methacryloyl (GelMA)-based bioink to make perfusable hydrogel-based microfluidic chips. We then demonstrated the scalability and customization flexibility of our hydrogel-based chip via engineering tools. A multiscale physical and structural data analysis suggested a relationship between cell invasion response and bioink characteristics. Tumor cell invasive behavior and focal adhesion properties were observed in response to varying polymer network densities of the GelMA-based bioink. Immunostaining assays and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) helped assess the bioactivity of the microtissue and measure the cell invasion. The RT-qPCR data showed higher expressions of HIF-1α, CD44, and MMP2 genes in a lower polymer density, highlighting the correlation between bioink structural porosity, ECM stiffness, and tumor spheroid response. This work is the first step in modeling STS tumor invasiveness in hydrogel-based microfluidic chips. STATEMENT OF SIGNIFICANCE: We optimized an engineering protocol for making tumor spheroids at a controlled size, embedding spheroids into a gelatin-based matrix, and constructing a perfusable microfluidic device. A higher tumor invasion was observed in a low-stiffness matrix than a high-stiffness matrix. The physical characterizations revealed how the stiffness is controlled by the density of polymer chain networks and porosity. The biological assays revealed how the structural properties of the gelatin matrix and hypoxia in tumor progression impact cell invasion. This work can contribute to personalized medicine by making more effective, tailored cancer models.

Advanced Hydrogels in Breast Cancer Therapy

Breast cancer is the most common malignancy among women and is the second leading cause of cancer-related death for women. Depending on the tumor grade and stage, breast cancer is primarily treated with surgery and antineoplastic therapy. Direct or indirect side effects, emotional trauma, and unpredictable outcomes accompany these traditional therapies, calling for therapies that could improve the overall treatment and recovery experiences of patients. Hydrogels, biomimetic materials with 3D network structures, have shown great promise for augmenting breast cancer therapy. Hydrogel implants can be made with adipogenic and angiogenic properties for tissue integration. 3D organoids of malignant breast tumors grown in hydrogels retain the physical and genetic characteristics of the native tumors, allowing for post-surgery recapitulation of the diseased tissues for precision medicine assessment of the responsiveness of patient-specific cancers to antineoplastic treatment. Hydrogels can also be used as carrier matrices for delivering chemotherapeutics and immunotherapeutics or as post-surgery prosthetic scaffolds. The hydrogel delivery systems could achieve localized and controlled medication release targeting the tumor site, enhancing efficacy and minimizing the adverse effects of therapeutic agents delivered by traditional procedures. This review aims to summarize the most recent advancements in hydrogel utilization for breast cancer post-surgery tissue reconstruction, tumor modeling, and therapy and discuss their limitations in clinical translation.

Organoid bioinks: construction and application

Organoids have emerged as crucial platforms in tissue engineering and regenerative medicine but confront challenges in faithfully mimicking native tissue structures and functions. Bioprinting technologies offer a significant advancement, especially when combined with organoid bioinks-engineered formulations designed to encapsulate both the architectural and functional elements of specific tissues. This review provides a rigorous, focused examination of the evolution and impact of organoid bioprinting. It emphasizes the role of organoid bioinks that integrate key cellular components and microenvironmental cues to more accurately replicate native tissue complexity. Furthermore, this review anticipates a transformative landscape invigorated by the integration of artificial intelligence with bioprinting techniques. Such fusion promises to refine organoid bioink formulations and optimize bioprinting parameters, thus catalyzing unprecedented advancements in regenerative medicine. In summary, this review accentuates the pivotal role and transformative potential of organoid bioinks and bioprinting in advancing regenerative therapies, deepening our understanding of organ development, and clarifying disease mechanisms.

Revolutionizing pancreatic islet organoid transplants: Improving engraftment and exploring future frontiers

Type-1 Diabetes Mellitus (T1DM) manifests due to pancreatic beta cell destruction, causing insulin deficiency and hyperglycaemia. Current therapies are inadequate for brittle diabetics, necessitating pancreatic islet transplants, which however, introduces its own set of challenges such as paucity of donors, rigorous immunosuppression and autoimmune rejection. Organoid technology represents a significant stride in the field of regenerative medicine and bypasses donor-based approaches. Hence this article focuses on strategies enhancing the in vivo engraftment of islet organoids (IOs), namely vascularization, encapsulation, immune evasion, alternative extra-hepatic transplant sites and 3D bioprinting. Hypoxia-induced necrosis and delayed revascularization attenuate organoid viability and functional capacity, alleviated by the integration of diverse cell types e.g., human amniotic epithelial cells (hAECs) and human umbilical vein endothelial cells (HUVECs) to boost vascularization. Encapsulation with biocompatible materials and genetic modifications counters immune damage, while extra-hepatic sites avoid surgical complications and immediate blood-mediated inflammatory reactions (IBMIR). Customizable 3D bioprinting may help augment the viability and functionality of IOs. While the clinical translation of IOs faces hurdles, preliminary results show promise. This article underscores the importance of addressing challenges in IO transplantation to advance their use in treating type 1 diabetes effectively.

Recent advances in 3D bioprinting for cancer research: From precision models to personalized therapies

Cancer remains one of the most devastating diseases, necessitating innovative and precise therapeutic solutions. The emergence of 3D bioprinting has revolutionized the platform of cancer therapy by offering bespoke solutions for drug screening, tumor modeling, and personalized medicine. The utilization of 3D bioprinting enables the fabrication of complex tumor models that closely mimic the in vivo microenvironment, facilitating more accurate drug testing and personalized treatment strategies. Moreover, 3D bioprinting also provides a platform for the development of implantable scaffolds as a therapeutic solution to cancer. In this review, we highlight the application of 3D bioprinting for cancer therapy along with current advancements in cancer 3D model development with recent case studies.

Embedded bioprinted multicellular spheroids modeling pancreatic cancer bioarchitecture towards advanced drug therapy

The desmoplastic bioarchitecture and microenvironment caused by fibroblasts have been confirmed to be closely related to the drug response behavior of pancreatic ductal adenocarcinoma (PDAC). Despite the extensive progress in developing PDAC models as in vitro drug screening platforms, developing efficient and controllable approaches for the construction of physiologically relevant models remains challenging. In the current study, multicellular spheroid models that emulate pancreatic cancer bioarchitecture and the desmoplastic microenvironment are bioengineered. An extrusion-based embedded dot bioprinting strategy was established to fabricate PDAC spheroids in a one-step process. Cell-laden hydrogel beads were directly deposited into a methacrylated gelatin (GelMA) suspension bath to generate spherical multicellular aggregates (SMAs), which further progressed into dense spheroids through in situ self assembly. By modulating the printing parameters, SMAs, even from multiple cell components, could be manipulated with tunable size and flexible location, achieving tunable spheroid patterns within the hydrogel bath with reproducible morphological features. To demonstrate the feasibility of this printing strategy, we fabricated desmoplastic PDAC spheroids by printing SMAs consisting of tumor cells and fibroblasts within the GelMA matrix bath. The produced hybrid spheroids were further exposed to different concentrations of the drug gemcitabine to verify their potential for use in cell therapy. Beyond providing a robust and facile bioprinting system that enables desmoplastic PDAC bioarchitecture bioengineering, this work introduces an approach for the scalable, flexible and rapid fabrication of cell spheroids or multi-cell-type spheroid patterns as platforms for advanced drug therapy or disease mechanism exploration.

Embedded 3D bioprinting - An emerging strategy to fabricate biomimetic & large vascularized tissue constructs

Three-dimensional bioprinting is an advanced tissue fabrication technique that allows printing complex structures with precise positioning of multiple cell types layer-by-layer. Compared to other bioprinting methods, extrusion bioprinting has several advantages to print large-sized tissue constructs and complex organ models due to large build volume. Extrusion bioprinting using sacrificial, support and embedded strategies have been successfully employed to facilitate printing of complex and hollow structures. Embedded bioprinting is a gel-in-gel approach developed to overcome the gravitational and overhanging limits of bioprinting to print large-sized constructs with a micron-scale resolution. In embedded bioprinting, deposition of bioinks into the microgel or granular support bath will be facilitated by the sol-gel transition of the support bath through needle movement inside the granular medium. This review outlines various embedded bioprinting strategies and the polymers used in the embedded systems with advantages, limitations, and efficacy in the fabrication of complex vascularized tissues or organ models with micron-scale resolution. Further, the essential requirements of support bath systems like viscoelasticity, stability, transparency and easy extraction to print human scale organs are discussed. Additionally, the organs or complex geometries like vascular constructs, heart, bone, octopus and jellyfish models printed using support bath assisted printing methods with their anatomical features are elaborated. Finally, the challenges in clinical translation and the future scope of these embedded bioprinting models to replace the native organs are envisaged.

Construction of tumor organoids and their application to cancer research and therapy

Cancer remains a severe public health burden worldwide. One of the challenges hampering effective cancer therapy is that the existing cancer models hardly recapitulate the tumor microenvironment of human patients. Over the past decade, tumor organoids have emerged as an in vitro 3D tumor model to mimic the pathophysiological characteristics of parental tumors. Various techniques have been developed to construct tumor organoids, such as matrix-based methods, hanging drop, spinner or rotating flask, nonadhesive surface, organ-on-a-chip, 3D bioprinting, and genetic engineering. This review elaborated on cell components and fabrication methods for establishing tumor organoid models. Furthermore, we discussed the application of tumor organoids to cancer modeling, basic cancer research, and anticancer therapy. Finally, we discussed current limitations and future directions in employing tumor organoids for more extensive applications.

Current Biomedical Applications of 3D-Printed Hydrogels

Three-dimensional (3D) printing, also known as additive manufacturing, has revolutionized the production of physical 3D objects by transforming computer-aided design models into layered structures, eliminating the need for traditional molding or machining techniques. In recent years, hydrogels have emerged as an ideal 3D printing feedstock material for the fabrication of hydrated constructs that replicate the extracellular matrix found in endogenous tissues. Hydrogels have seen significant advancements since their first use as contact lenses in the biomedical field. These advancements have led to the development of complex 3D-printed structures that include a wide variety of organic and inorganic materials, cells, and bioactive substances. The most commonly used 3D printing techniques to fabricate hydrogel scaffolds are material extrusion, material jetting, and vat photopolymerization, but novel methods that can enhance the resolution and structural complexity of printed constructs have also emerged. The biomedical applications of hydrogels can be broadly classified into four categories-tissue engineering and regenerative medicine, 3D cell culture and disease modeling, drug screening and toxicity testing, and novel devices and drug delivery systems. Despite the recent advancements in their biomedical applications, a number of challenges still need to be addressed to maximize the use of hydrogels for 3D printing. These challenges include improving resolution and structural complexity, optimizing cell viability and function, improving cost efficiency and accessibility, and addressing ethical and regulatory concerns for clinical translation.

Exploring the interaction between extracellular matrix components in a 3D organoid disease model to replicate the pathophysiology of breast cancer

In vitro models are necessary to study the pathophysiology of the disease and the development of effective, tailored treatment methods owing to the complexity and heterogeneity of breast cancer and the large population affected by it. The cellular connections and tumor microenvironments observed in vivo are often not recapitulated in conventional two-dimensional (2D) cell cultures. Therefore, developing 3D in vitro models that mimic the complex architecture and physiological circumstances of breast tumors is crucial for advancing our understanding of the illness. A 3D scaffold-free in vitro disease model mimics breast cancer pathophysiology by allowing cells to self-assemble/pattern into 3D structures, in contrast with other 3D models that rely on artificial scaffolds. It is possible that this model, whether applied to breast tumors using patient-derived primary cells (fibroblasts, endothelial cells, and cancer cells), can accurately replicate the observed heterogeneity. The complicated interactions between different cell types are modelled by integrating critical components of the tumor microenvironment, such as the extracellular matrix, vascular endothelial cells, and tumor growth factors. Tissue interactions, immune cell infiltration, and the effects of the milieu on drug resistance can be studied using this scaffold-free 3D model. The scaffold-free 3D in vitro disease model for mimicking tumor pathophysiology in breast cancer is a useful tool for studying the molecular basis of the disease, identifying new therapeutic targets, and evaluating treatment modalities. It provides a more physiologically appropriate high-throughput platform for screening large compound library in a 96-384 well format. We critically discussed the rapid development of personalized treatment strategies and accelerated drug screening platforms to close the gap between traditional 2D cell culture and in vivo investigations.