DNA origami vaccines could be the next leap beyond mRNA

The global scientific and public health communities are witnessing a potential paradigm shift in vaccine technology with the emergence of DoriVac, a novel DNA origami nanotechnology platform. Developed by a multidisciplinary team from the Wyss Institute at Harvard University, Dana-Farber Cancer Institute (DFCI), and partner institutions, DoriVac represents a significant leap forward, offering a versatile and robust alternative to existing vaccine strategies, particularly in overcoming the critical limitations exposed by the widespread deployment of messenger RNA (mRNA) vaccines during the COVID-19 pandemic. While mRNA vaccines undeniably played a pivotal role in mitigating the pandemic’s devastation, their inherent challenges in terms of stability, manufacturing complexity, and cold-chain requirements have underscored the urgent need for more resilient and globally accessible solutions.

The mRNA Revolution and Its Unforeseen Challenges

The COVID-19 pandemic thrust mRNA vaccines into the global spotlight with unprecedented speed and impact. Following rigorous clinical trials, the first COVID-19 mRNA vaccine was administered on December 8, 2020, marking a historic moment in medical science. Researchers, leveraging sophisticated modeling techniques, have since estimated that these innovative vaccines prevented at least 14.4 million deaths worldwide during their initial year of deployment. This remarkable success ignited a flurry of research and development, with scientists now actively exploring mRNA vaccine candidates for a broad spectrum of other infectious diseases, including influenza virus, Respiratory Syncytial Virus (RSV), HIV, Zika, Epstein-Barr virus, and tuberculosis bacteria. The promise of rapid development and high efficacy has positioned mRNA technology as a cornerstone of modern vaccinology.

However, the rapid global rollout and continuous monitoring of COVID-19 mRNA vaccines also brought to light several important limitations that necessitate new strategic approaches. One primary concern is the variability in immune protection generated by these vaccines, which can differ widely from person to person. Furthermore, the protection conferred is not indefinite, necessitating booster shots and raising questions about long-term immunity. This challenge is compounded by the relentless evolution of SARS-CoV-2, the virus responsible for COVID-19. New variants frequently emerge, exhibiting mutations that allow them to partially escape existing immune defenses, thereby reducing vaccine effectiveness and often requiring updated vaccine formulations to maintain protection. This constant arms race between virus and vaccine places significant pressure on public health systems and vaccine manufacturers alike.

Beyond immunological considerations, practical hurdles associated with mRNA vaccine production and distribution are substantial. Manufacturing mRNA vaccines is a complex and expensive process, demanding specialized facilities and expertise. A key technical challenge lies in precisely controlling the packaging of mRNA molecules into lipid nanoparticles (LNPs), which are essential for delivering the genetic material into human cells. Perhaps the most significant logistical barrier, particularly for global distribution and equitable access, is the stringent cold-chain requirement. mRNA vaccines, especially earlier formulations, often demand ultra-cold storage at temperatures as low as -70°C, posing immense challenges for transportation and storage in regions with limited infrastructure, unreliable power supplies, or extreme climates. Additionally, there have been observations of potential unintended off-target effects, though these are generally rare and mild. Overcoming these multifaceted limitations is paramount for enhancing global preparedness and response capabilities for future infectious disease threats.

Introducing DoriVac: A Nanotechnology Platform for Precision Immunology

In response to these pressing issues, a pioneering multidisciplinary team comprising experts from the Wyss Institute at Harvard University, Dana-Farber Cancer Institute (DFCI), and other partner institutions embarked on an innovative quest for an alternative solution. Their exploration led to the development of DoriVac, a groundbreaking DNA origami nanotechnology platform designed to function synergistically as both a vaccine and an adjuvant. This dual functionality is a crucial differentiator, as adjuvants are substances that enhance the immune response to a vaccine, often a critical component for achieving robust and lasting protection. The precision offered by nanotechnology allows for an unprecedented level of control over vaccine design and presentation.

The foundational concept behind DoriVac stems from the sophisticated field of DNA origami, where DNA molecules are precisely folded and self-assembled into predefined 2D or 3D nanostructures. This allows researchers to engineer nanoscale platforms with exquisite control over their physical properties and the spatial arrangement of molecular components. In the case of DoriVac, these tiny, self-assembling square DNA nanostructures are meticulously crafted. One side of these nanostructures is engineered to display immune-stimulating adjuvant molecules, strategically arranged at carefully controlled nanometer distances. This precise spatial arrangement is hypothesized to optimize their interaction with immune cells, thereby maximizing the adjuvant effect. The opposite side of the nanostructure is then configured to present selected antigens—specific peptides or proteins derived from pathogens or even tumors. This modular design offers remarkable flexibility, allowing for the rapid interchange of antigens to target different diseases or viral variants.

The DoriVac platform was initially conceived and developed for oncology applications, with preliminary studies in tumor-bearing mice demonstrating that these DNA origami-based vaccines produced stronger immune responses compared to versions lacking the DNA origami structure. This early success underscored the potential of the nanotechnology chassis to enhance immune stimulation. Dr. Yang (Claire) Zeng, M.D., Ph.D., who led the initial development effort and is now cofounder and CEO/CTO of DoriNano, recalls the pivotal moment: "While we were developing the platform for cancer applications, the COVID-19 pandemic was still moving with full force. So, the question quickly arose whether DoriVac’s superior adjuvant activity could also be leveraged in infectious disease settings." This critical insight redirected a portion of the research focus towards addressing the global health crisis.

Rigorous Preclinical Validation: From Conserved Targets to Human Models

To explore DoriVac’s potential in combating infectious diseases, Dr. Zeng and co-first author Dr. Olivia Young, a former graduate student in Dr. Shih’s group, initiated a collaborative effort with Dr. Donald Ingber’s team at the Wyss Institute. Ingber’s group is renowned for its innovative work in antiviral innovation, employing AI-driven and multiomics approaches alongside sophisticated microfluidic human Organ Chip systems. Together with co-first author Dr. Longlong Si, a former postdoctoral researcher in Ingber’s lab, the researchers meticulously developed DoriVac vaccines specifically targeting SARS-CoV-2, HIV, and Ebola. A key strategic decision in their design was to focus on presenting HR2 peptides. These peptides represent highly conserved regions within the viral spike proteins of these pathogens, meaning they are less likely to mutate and thus could potentially elicit broader and more durable protection against a wider range of viral strains or variants.

The initial validation phase involved extensive studies in mouse models. The findings were highly encouraging. The SARS-CoV-2 HR2 DoriVac vaccine successfully triggered robust immune responses, encompassing both antibody-driven (humoral) and T cell-driven (cellular) activity. Dr. Zeng elaborated on these observations: "Our analysis of the immune responses provoked by these first DoriVac vaccines in mice led to several encouraging observations, including significantly greater and broader activation of humoral and cellular immunity across a range of relevant immune cell types than what the origami-free antigens and adjuvants could produce." Specifically, the team observed increases in critical immune cell populations: antibody-producing B cells, activated antigen-presenting dendritic cells (DCs), and antigen-specific memory and cytotoxic T cell types—all vital components for long-term protection against pathogens. This enhanced activation was particularly pronounced in the case of the SARS-CoV-2 HR2 vaccine, suggesting its potent immunogenic potential.

A persistent challenge in vaccine development has been the translational gap between preclinical animal studies and human outcomes. Immune responses in mice, while informative, often do not fully predict how a vaccine will perform in humans, leading to numerous promising candidates failing in later-stage clinical trials. To mitigate this risk and gain a more accurate foresight into human efficacy, the team ingeniously leveraged the Wyss Institute’s microfluidic human Organ Chip technology. Specifically, they utilized a human lymph node-on-a-chip (human LN Chip), an advanced in vitro system that meticulously mimics key aspects of the human immune system’s response within a controlled microenvironment.

This cutting-edge system, further advanced by co-first author Min Wen Ku and co-corresponding author Dr. Girija Goyal, Director of Bioinspired Therapeutics at the Wyss Institute, provided invaluable insights. In the human LN Chip, the SARS-CoV-2-HR2 DoriVac vaccine demonstrated its ability to effectively activate human dendritic cells and significantly boost their production of inflammatory cytokines, crucial signaling molecules that orchestrate immune responses. This activation was markedly superior when compared to origami-free vaccine components, highlighting the unique advantages of the DNA origami platform. Furthermore, the DoriVac vaccine led to an increased proliferation of CD4+ and CD8+ T cells, both of which possess multiple protective functions essential for combating viral infections. These compelling results in a human-relevant model provide strong preclinical support for the platform’s potential for human therapeutic use. Dr. Ingber underscored the significance of this approach, stating, "The predictive capabilities of human LN Chips gave us an ideal testing ground for DoriVac vaccines and the induced, antigen-specific immune cell profiles and activities very likely reflect those that would occur in human recipients of the vaccines. This convergence of technologies enabled us to dramatically raise the chances of success for a new class of vaccines and create a new testbed for future vaccine developments."

DoriVac Versus mRNA: A Head-to-Head Comparison Revealing Key Advantages

To comprehensively evaluate DoriVac’s competitive edge, the researchers conducted a direct head-to-head comparison against established mRNA vaccines. Led by Dr. Zeng and co-author Qiancheng Xiong, the team designed a DoriVac vaccine presenting the full SARS-CoV-2 spike protein and compared its immunogenicity to that of commercially available Moderna and Pfizer/BioNTech mRNA lipid nanoparticle (LNP) vaccines, which encode the identical spike protein. Utilizing a standard booster approach in mouse models, both vaccine types elicited remarkably similar antiviral T cell and antibody-producing B cell responses. This finding is profoundly significant, as it demonstrates that DoriVac can achieve an equivalent level of immune activation to the highly effective mRNA vaccines, but potentially without some of their inherent drawbacks.

Dr. William Shih, Ph.D., a co-corresponding author and Wyss Institute Core Faculty member whose group pioneered the new vaccine concept, emphasized the broader implications: "This underscored DoriVac’s potential as a DNA nanotechnology-enabled, self-adjuvanted vaccine platform. But DoriVac vaccines have a number of other advantages: they don’t have the same cold-chain requirements as mRNA-LNP vaccines do and thus could be distributed much more effectively, especially in under-resourced regions; and they could overcome some of the enormous manufacturing complexities of LNP-formulated vaccines, to name two major ones." The ability to eliminate or significantly reduce cold-chain reliance is a game-changer for global vaccine distribution. While mRNA vaccines often require ultra-cold storage, DoriVac’s inherent stability could allow for storage at standard refrigeration temperatures or even room temperature, drastically simplifying logistics and reducing costs, particularly in low-income countries where cold-chain infrastructure is often lacking or unreliable. Furthermore, the self-assembling nature of DNA origami structures could streamline manufacturing processes, potentially leading to more scalable and cost-effective production compared to the intricate LNP formulation required for mRNA vaccines. Recent studies conducted at DoriNano have also provided promising data regarding DoriVac’s safety profile, further bolstering its appeal.

Broader Impact and Implications: A New Era of Pandemic Preparedness

The development of the DoriVac platform holds profound implications for global health and future pandemic preparedness. By directly addressing the critical limitations of mRNA vaccines—namely, their variable efficacy, non-indefinite protection, susceptibility to viral evolution, manufacturing complexity, high cost, and stringent cold-chain requirements—DoriVac offers a compelling alternative that could significantly improve the world’s ability to respond to emerging infectious disease threats. The platform’s inherent stability, ease of storage, and potentially simpler manufacturing process make it an ideal candidate for equitable global distribution, particularly to under-resourced regions that have historically faced significant barriers to accessing life-saving vaccines.

The versatility of the DoriVac platform, demonstrated by its ability to effectively target conserved regions of multiple viruses like SARS-CoV-2, HIV, and Ebola, positions it as a robust "plug-and-play" system. This adaptability means that researchers could rapidly integrate new antigens from emerging pathogens into the DoriVac framework, accelerating vaccine development timelines during future outbreaks. The precise control over vaccine composition and the ability to program immune recognition at a molecular level, as highlighted by Dr. Shih, suggest a future where vaccines are tailored with unprecedented accuracy to elicit optimal immune responses against specific threats.

Moreover, the successful integration of human Organ Chip technology into the preclinical validation process represents a significant methodological advancement. By providing a more human-relevant testing ground, this approach can reduce reliance on animal models, accelerate discovery, and increase the likelihood of success in human clinical trials, thereby shortening the overall vaccine development pipeline. This convergence of advanced nanotechnology and sophisticated human-on-chip systems creates a powerful new testbed for future vaccine innovations.

The initial work on DoriVac for cancer applications also points to its broad therapeutic potential beyond infectious diseases. If successful, this platform could usher in a new era of precision medicine, offering highly effective and customizable vaccine strategies for both prophylactic (preventative) and therapeutic applications. As DoriNano, the company co-founded by Dr. Zeng, takes the lead in translating this technology into clinical applications, the next critical step will be to move DoriVac into human clinical trials to confirm its safety and efficacy in people. The successful navigation of these trials could cement DoriVac’s position as a cornerstone technology in the global fight against infectious diseases and other significant health challenges.

This groundbreaking research was supported by a diverse array of funding bodies, underscoring the collaborative and globally recognized importance of this work. Contributions came from the Director’s Fund and Validation Project program of the Wyss Institute; the Claudia Adams Barr Program at DFCI; the National Institutes of Health (U54 grant CA244726-01); the US-Japan CRDF global fund (grant R-202105-67765); the National Research Foundation of Korea (grants MSIT, RS-2024-00463774, RS-2023-00275456); the Intramural Research Program of the Korea Institute of Science and Technology (KIST); and the Bill and Melinda Gates Foundation (INV-002274). The extensive list of contributing authors, including Sylvie Bernier, Hawa Dembele, Giorgia Isinelli, Tal Gilboa, Zoe Swank, Su Hyun Seok, Anjali Rajwar, Amanda Jiang, Yunhao Zhai, LaTonya Williams, Caleb Hellman, Chris Wintersinger, Amanda Graveline, Andyna Vernet, Melinda Sanchez, Sarai Bardales, Georgia Tomaras, Ju Hee Ryu, and Ick Chan Kwon, highlights the vast collaborative effort required to bring such a complex and promising innovation to fruition. The findings, published in the esteemed journal Nature Biomedical Engineering, signal a new chapter in vaccine science, one where precision nanotechnology promises to overcome existing hurdles and forge a path towards a more resilient and equitable global health future.