Central to this innovation is the use of a bioengineered hydrogel scaffold that envelops thin slices of lymph node tissue, preserving both its microarchitecture and cellular viability for up to a week. Traditionally, lymph node explants degrade rapidly in vitro, losing structural integrity and immunological function within one or two days, thereby limiting meaningful analyses. The hydrogel utilized in this approach is hyaluronan-based, biomimicking the native extracellular matrix to sustain the tissue’s three-dimensional environment, thus facilitating more physiologically relevant conditions for immune cell interactions.

Lymph nodes, shaped like small beans, are pivotal immune hubs where antigen presentation and lymphocyte activation occur. However, recapitulating this complexity outside a living organism has been a formidable challenge. Often, immunological research depends heavily on animal models or simplified two-dimensional cultures that fail to capture the true intricacies of human immune responses. This newly engineered system overcomes these obstacles by maintaining the native spatial arrangement and cellular diversity of human lymphoid tissue, allowing researchers to observe real-time immune dynamics with remarkable fidelity.

The team sourced non-involved lymph node tissues from head and neck cancer patients undergoing surgical resections, meticulously preparing thin slices to be embedded within the hydrogel matrix. This innovative embedding strategy creates a supportive microenvironment, preventing the rapid tissue breakdown typically observed in suspension cultures. Through this, the explants retained their size and histological features while sustaining cellular metabolism and signaling pathways critical for immune function over a significantly prolonged period.

Upon exposure to immunological stimuli—including autologous cancer cells and COVID-19 mRNA vaccines—the lymph node explants demonstrated robust immune responsiveness. The tissues secreted cytokines and chemokines indicative of immune activation, recruited and activated immune cell populations, and even synthesized antibodies. Remarkably, one sample displayed an active immune signature prior to vaccine administration, suggesting the system’s capability to reflect a patient’s unique immunological history, shaped by prior infections or immunizations.

Assistant Professor Eliza Fong, from NUS’s Department of Biomedical Engineering and co-leader of the study, emphasized the platform’s transformative potential. By faithfully replicating human immune tissue behavior ex vivo, it affords researchers a superior experimental model that captures interindividual variability in immune responses. This granularity is vital for advancing personalized medicine approaches, tailoring vaccines, and immunotherapies to suit individual patient profiles more accurately than preclinical models allow.

Furthermore, the research underscores the importance of preserving tissue architecture, as the spatial organization within lymph nodes orchestrates complex cell-cell communications essential for effective immunity. The hydrogel scaffold ensures that critical microenvironments—such as germinal centers where B cells mature—remain intact and operable. This preservation enables detailed mechanistic studies of adaptive immunity, including how immune cells migrate, proliferate, and interact in response to pathogens or tumor antigens.

While the current system sustains tissue viability and functionality for approximately one week, ongoing efforts aim to extend this longevity and replicate physiological parameters more comprehensively. Future refinements include integrating fluid dynamics to mimic lymph flow, which plays a crucial role in immune cell trafficking and antigen delivery. Such enhancements would create an even more faithful in vitro immune microenvironment, further bridging the gap between laboratory models and human biology.

The implications of this work extend to the preclinical evaluation of vaccines and immunotherapies. By providing a human-relevant testing platform that bypasses the limitations of animal models, it promises to accelerate the development pipeline for new treatments. Moreover, it could reduce reliance on animal experimentation, aligning with ethical imperatives and potentially increasing the predictive accuracy of immune-mediated therapeutic responses.

Professor N Gopalakrishna Iyer, a senior consultant at the National Cancer Centre Singapore and co-leader of this project, highlighted the model’s capacity to reveal the temporal evolution of immune responses. Tracking immune kinetics in real time within preserved human tissue opens the door to novel insights into disease mechanisms, vaccine efficacy, and immune escape phenomena in cancer and infectious diseases.

This pioneering research was detailed in the Cell Press journal Trends in Biotechnology on 29 August 2025, marking a significant milestone in immunological bioengineering. The collaborative efforts exemplify how interdisciplinary approaches—melding biomaterials science, tissue engineering, and clinical insights—can converge to address long-standing challenges in understanding human immunity.

Ultimately, the creation of extended human lymph node explants represents a powerful new tool that will reshape immunological research and therapeutic development. As the platform evolves, it holds promise for unraveling the complexities of human adaptive immunity with unparalleled precision, paving the way for more effective, tailored disease interventions in the near future.

Subject of Research: Cells

Article Title: Extended human lymph node explants for evaluation of adaptive immunity

News Publication Date: 29-Aug-2025

Web References: 10.1016/j.tibtech.2025.07.020

Image Credits: College of Design and Engineering at National University of Singapore

Ex vivo functional whole organ research involves the utilization of isolated organs that are perfused with blood or nutrient solutions to preserve their functionality outside of the body. This technique provides scientists with a dynamic platform for studying organ physiology and pathology under conditions that closely approximate in vivo environments. Importantly, these models allow for real-time observation of organ responses to various stimuli, including drug applications or pathological conditions. The implications of using such models for preclinical drug testing are immense, promising to reduce the reliance on animal models and potentially speeding up the drug discovery process.

One of the notable highlights from Chelladurai et al.’s review is the striking ability of ex vivo models to reconstruct complex organ systems. These models serve as an invaluable resource for understanding multi-organ interactions, reflecting the interconnectedness of bodily systems in ways that traditional in vitro models cannot achieve. For example, researchers can investigate the influence of liver metabolism on cardiac function or assess how renal clearance affects drug efficacy throughout the body. This comprehensive approach mirrors the realities of human physiology far more accurately than isolated cell studies.

The technology behind ex vivo organ studies has advanced significantly, utilizing sophisticated biosensors and imaging techniques to monitor organ health in real-time. With developments in microfluidics, researchers have been able to create closed-loop systems that closely mimic physiological conditions. This innovation is crucial; it permits sustained organ viability while exposing them to various experimental conditions. The potential for using these models to evaluate the toxicity of new compounds, biology of diseases, and efficacy of therapeutic strategies presents a promising frontier in medical research.

Despite the numerous advantages, the authors of the review articulate some challenges associated with ex vivo functional whole organ research. One significant hurdle is the preservation of organ viability over extended periods, which remains a focus of ongoing efforts in the field. Optimal perfusion techniques and solutions must be refined to enhance the longevity of organ functionality. As researchers continue to solve these challenges, the pathway for integrating ex vivo organ studies into standard biomedical practice becomes increasingly clear.

Furthermore, ethical considerations surrounding organ sourcing and usage remain pivotal. The use of organs from organ donors raises questions about the ethical implications of their employment in research. Chelladurai et al. suggest that developing robust guidelines and ethical frameworks surrounding these practices is essential. As such, stakeholder engagement—including the perspectives of donors, patients, and the public—should inform the development of policies that govern the use of ex vivo models.

A particularly exciting aspect of this research touches on personalized medicine, where ex vivo organ models could be tailored to an individual patient’s tissue. Such models could revolutionize the entire landscape of therapeutic approaches, allowing for drug testing to be conducted on personalized organ replicas developed from a patient’s own cells. This dovetails neatly with current trends towards precision medicine, which focus on individual treatment plans based on genetic, environmental, and lifestyle factors.

Moreover, the implications of ex vivo functional organ studies extend beyond drug testing, reaching into the realm of education and training. Medical students and professionals can benefit enormously from the ability to study these organ systems in a controlled environment, enhancing their understanding of physiological functions in a manner that traditional educational models simply cannot provide. This hands-on approach to learning fosters a deeper comprehension of complex biological processes, ensuring that future healthcare professionals are better prepared for clinical challenges.

Perhaps one of the most intriguing applications of functional whole organ research is its potential impact on regenerative medicine. Insights gained from ex vivo studies may accelerate the development of bioengineered organs and tissues. By understanding the principles that govern organ function in a controlled environment, researchers are better positioned to create artificial organs that can truly mimic their natural counterparts. This intersection of engineering and biology could lead to groundbreaking advances in transplantation and organ replacement therapies.

As the parallels between ex vivo organ studies and real-world clinical applications continue to unfold, it becomes evident that this research area is at the forefront of a biomedical revolution. The convergence of technology, ethical considerations, education, and personalized medicine represents an inflection point for the future of organ-based research and therapy. In a world where chronic diseases and organ failures are on the rise, the pursuit of innovative solutions through ex vivo models may very well offer hope to millions around the globe.

In conclusion, the meticulous exploration of functional whole organ models as highlighted in the review by Chelladurai et al. underscores a pivotal advancement in biomedical sciences. As we stand on the precipice of new horizons in medical research and treatment methodologies, the ongoing efforts to refine and implement these ex vivo organ systems will undoubtedly pave the way for significant breakthroughs in our understanding of human health and disease.

The pioneering work in ex vivo functional whole organ research heralds a new era in medicine that promises better therapeutic outcomes and enhanced understanding of complex diseases, ultimately providing a brighter future for patient care worldwide.

Subject of Research: Ex vivo functional whole organ in biomedical research

Article Title: Ex vivo functional whole organ in biomedical research: a review

Article References:

Subbiahanadar Chelladurai, K., Selvan Christyraj, J.D., Rajagopalan, K. et al. Ex vivo functional whole organ in biomedical research: a review.
J Artif Organs 28, 131–145 (2025). https://doi.org/10.1007/s10047-024-01478-4

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s10047-024-01478-4

Keywords: Ex vivo; functional whole organ; biomedical research; organ models; personalized medicine; drug testing; regenerative medicine.