Harvard Scientists Unveil DNA Origami Vaccine Platform Offering Stable, Scalable Alternative to mRNA Technology

The COVID-19 pandemic undeniably propelled messenger RNA (mRNA) vaccines into the global consciousness, showcasing their unprecedented speed of development and life-saving potential. Following an expedited yet rigorous clinical trial process, the world witnessed the administration of the first COVID-19 mRNA vaccine on December 8, 2020. The impact was profound; researchers later employed sophisticated modeling techniques to estimate that these innovative vaccines averted at least 14.4 million deaths worldwide within their inaugural year of deployment. This remarkable achievement sparked a global scientific race, with researchers swiftly pivoting to adapt mRNA technology for a broad spectrum of other infectious diseases. Clinical trials are currently underway, targeting pervasive threats such as the influenza virus, Respiratory Syncytial Virus (RSV), HIV, Zika, Epstein-Barr virus, and even the resilient tuberculosis bacteria, underscoring the technology’s perceived versatility.

However, the rapid deployment and extensive real-world application of COVID-19 mRNA vaccines have also illuminated critical limitations, pointing to an urgent need for diversified and more robust vaccine strategies. While groundbreaking, these challenges, spanning efficacy, durability, and logistical hurdles, have spurred a new wave of innovation in vaccinology.

The Dual Edge of mRNA Vaccines: Triumphs and Tribulations

The success of mRNA vaccines during the pandemic was a scientific marvel, demonstrating the capacity to rapidly design and deploy vaccines against emerging pathogens. This speed was largely attributed to the platform’s ability to utilize a genetic blueprint (mRNA) to instruct human cells to produce viral proteins, thereby triggering an immune response without introducing live virus. The underlying technology, often encapsulated within lipid nanoparticles (LNPs), allowed for a modular approach, where changing the antigen merely required updating the mRNA sequence. This flexibility was crucial in responding to a fast-evolving virus like SARS-CoV-2.

Despite these triumphs, significant performance and production challenges have become apparent. One primary concern is the variability in immune protection generated by COVID-19 mRNA vaccines, which can differ widely from person to person. This individual-level variance can be influenced by factors such as age, underlying health conditions, and genetic predispositions. Furthermore, the protection conferred by these vaccines does not last indefinitely, necessitating booster shots. This issue is compounded by the relentless evolution of SARS-CoV-2, which continuously produces new variants capable of partially evading existing immune defenses—a phenomenon known as "immune escape." Consequently, vaccines often require frequent updates to maintain effectiveness against circulating strains, leading to a constant arms race between vaccine developers and the virus.

Beyond immunological aspects, the practical challenges associated with mRNA vaccine technology are substantial. Manufacturing mRNA vaccines is a complex and capital-intensive process, demanding specialized facilities and expertise. Controlling the precise packaging of mRNA molecules into lipid nanoparticles remains a formidable technical hurdle, impacting consistency and yield. Perhaps one of the most significant logistical impediments is the requirement for stringent cold-chain storage. Early mRNA vaccines notably required ultra-cold temperatures (as low as -70°C for some formulations), posing immense distribution challenges, particularly in low-resource settings or remote areas lacking sophisticated refrigeration infrastructure. This "cold chain" requirement has exacerbated vaccine inequity globally. Moreover, concerns about potential unintended off-target effects, though generally rare and mild, continue to be subjects of ongoing research and monitoring. Overcoming these multifaceted limitations is paramount for improving global preparedness and response to future infectious disease threats, fostering a more equitable and resilient public health landscape.

A Novel Horizon: The DNA Origami Vaccine Platform (DoriVac)

In response to these pressing challenges, a pioneering multidisciplinary team, uniting expertise from the Wyss Institute at Harvard University, Dana-Farber Cancer Institute (DFCI), and partner institutions, has embarked on an entirely novel approach. Their innovation centers on a DNA origami nanotechnology platform dubbed DoriVac, which ingeniously functions as both a vaccine antigen delivery system and an immune-stimulating adjuvant. This dual functionality represents a significant leap forward, aiming to circumvent many of the inherent difficulties associated with current vaccine technologies.

The DoriVac platform leverages the principles of DNA origami, a groundbreaking field within nanotechnology where DNA molecules are precisely folded into intricate, predetermined 2D and 3D nanostructures. This technique allows for exquisite control over the spatial arrangement of molecules at the nanoscale, enabling the creation of highly ordered and programmable vaccine constructs. The researchers meticulously designed DoriVac vaccines to target a specific peptide region (HR2) found in the spike proteins of several formidable viruses, including SARS-CoV-2, HIV, and Ebola. The selection of HR2 is strategic; it represents a relatively conserved region across different viral strains, offering the potential for broad-spectrum protection against evolving pathogens, unlike highly variable regions targeted by some conventional vaccines.

Initial preclinical studies conducted in mice yielded highly encouraging results. The SARS-CoV-2 HR2 DoriVac vaccine successfully triggered robust and comprehensive immune responses, encompassing both antibody-driven (humoral) activity and T cell-driven (cellular) immunity. The simultaneous activation of both arms of the adaptive immune system is crucial for durable and effective protection against viral infections, as antibodies primarily block infection, while T cells eliminate infected cells.

To further validate the platform’s potential in a context more predictive of human physiology, the team ingeniously tested the vaccine in a preclinical human model utilizing the Wyss Institute’s cutting-edge microfluidic human Organ Chip technology. Specifically, they employed a "human lymph node-on-a-chip" system, which precisely simulates the complex microenvironment and immune interactions of a human lymph node in vitro. Within this sophisticated system, the SARS-CoV-2 HR2 DoriVac vaccine also demonstrated its capacity to generate strong antigen-specific immune responses in human cells, providing a critical bridge between animal studies and future human clinical trials.

A pivotal comparative analysis further underscored DoriVac’s promise. When directly pitted against established SARS-CoV-2 mRNA vaccines delivered through lipid nanoparticles—specifically, a DoriVac vaccine carrying the identical spike protein variant—the DNA origami vaccine produced a similarly potent immune activation in human models. Crucially, however, the DoriVac platform exhibited distinct advantages in terms of stability, and was demonstrably easier to store and manufacture. These groundbreaking findings, which highlight DoriVac’s potential to address key limitations of mRNA vaccines, were recently detailed in the prestigious scientific journal Nature Biomedical Engineering.

Precision Engineering: How DNA Origami Vaccines Are Built

The conceptual foundation of DoriVac was laid in 2024, when William Shih, Ph.D., a Wyss Institute Core Faculty member and Professor at Harvard Medical School and DFCI, whose group pioneered the novel vaccine concept, and his team at the Wyss Institute and Dana-Farber initially introduced DoriVac as a DNA nanotechnology-based vaccine platform with broad potential applications, particularly in cancer immunotherapy. Yang (Claire) Zeng, M.D., Ph.D., who spearheaded the effort with collaborators, was instrumental in demonstrating DoriVac’s unique ability to precisely present immune-stimulating adjuvant molecules to cells at the nanoscale.

Earlier investigations into tumor-bearing mice had already revealed DoriVac’s superior performance in cancer applications, showing that these vaccines produced significantly stronger immune responses than versions lacking the precise DNA origami structure. This demonstrated the power of nanoscale organization in enhancing immunological signaling. DoriVac vaccines are meticulously constructed from minuscule, self-assembling square DNA nanostructures. One side of these precisely engineered structures is designed to display adjuvant molecules, which are critical components that enhance the immune response, arranged at carefully controlled nanometer distances. This precise spatial arrangement is believed to optimize their interaction with immune cells. The opposite side of the nanostructure is configured to present selected antigens, such as peptides or proteins derived from tumors or pathogens, effectively guiding the immune system to recognize and target specific threats.

"While we were developing the platform primarily for cancer applications, the COVID-19 pandemic was still moving with full force," recounted Zeng, who is a first and co-corresponding author on the new study and now the cofounder and CEO/CTO of DoriNano, a company actively translating this technology into clinical applications. "So, the question quickly arose whether DoriVac’s superior adjuvant activity, which we observed in cancer models, could also be leveraged effectively in infectious disease settings."

To rigorously explore this compelling hypothesis, Zeng, alongside co-first author Olivia Young, Ph.D., a former graduate student in Shih’s group, initiated a collaborative effort with Donald Ingber’s team at the Wyss Institute. Ingber’s group is renowned for its innovative work in antiviral strategies, employing cutting-edge AI-driven and multiomics approaches in conjunction with their advanced microfluidic human Organ Chip systems. Together with co-first author Longlong Si, Ph.D., a former postdoctoral researcher in Ingber’s lab, the researchers developed specific DoriVac vaccine formulations targeting SARS-CoV-2, HIV, and Ebola. These formulations were designed to present the HR2 peptides, strategically chosen for their role as conserved antigens within the respective viral spike proteins, offering a pathway to broader protection.

The comprehensive analysis of the immune responses provoked by these initial DoriVac vaccines in mice provided a wealth of encouraging observations. "We saw significantly greater and broader activation of both humoral and cellular immunity across a wide range of relevant immune cell types than what the origami-free antigens and adjuvants alone could produce," Zeng elaborated. This indicates that the DNA origami structure itself acts as an intrinsic immunomodulator, enhancing the vaccine’s potency. "Specifically, we found that the numbers of antibody-producing B cells, activated antigen-presenting dendritic cells (DCs)—which are crucial for initiating immune responses—and antigen-specific memory and cytotoxic T cell types, all vital for long-term protection against pathogens, were substantially increased, particularly in the case of the SARS-CoV-2 HR2 vaccine," Zeng further explained. These findings collectively paint a picture of a highly effective immune-stimulating platform.

From Preclinical Mouse Studies to Predictive Human Models

A persistent and often frustrating hurdle in vaccine development is the notorious discrepancy between immune responses observed in animal models, such as mice, and those that ultimately manifest in humans. This translational gap has historically caused numerous promising treatments and vaccine candidates to fail during costly and time-consuming human clinical trials, highlighting the urgent need for more predictive preclinical models.

To overcome this critical limitation and enhance the predictive power of their research, the Wyss Institute team strategically employed the human lymph node-on-a-chip (human LN Chip) system to test the DoriVac vaccines. This advanced microfluidic system, significantly refined and advanced by co-first author Min Wen Ku and co-corresponding author Girija Goyal, Ph.D., Director of Bioinspired Therapeutics at the Wyss Institute, meticulously mimics key architectural and functional aspects of the human immune system’s command centers.

The human LN Chip studies provided compelling evidence for DoriVac’s potential in humans. The SARS-CoV-2-HR2 DoriVac vaccine robustly activated human dendritic cells (DCs) within the chip, leading to a significant increase in their production of inflammatory cytokines—signaling molecules essential for orchestrating a potent immune response—compared with the origami-free vaccine components. Furthermore, the system demonstrated an increase in the number of CD4+ and CD8+ T cells, which are critical T lymphocyte subsets known for their multiple protective functions, including directly killing infected cells (CD8+) and coordinating the overall immune response (CD4+). These results further reinforced the platform’s potential for safe and effective human use.

Donald Ingber, M.D., Ph.D., a co-corresponding author on the study and the Judah Folkman Professor of Vascular Biology at Harvard Medical School and Boston Children’s Hospital, as well as the Hansjörg Wyss Professor of Biologically Inspired Engineering at Harvard John A. Paulson School of Engineering and Applied Sciences, emphasized the transformative impact of this technology. "The predictive capabilities of human LN Chips gave us an ideal testing ground for DoriVac vaccines," he stated. "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 has enabled us to dramatically raise the chances of success for a new class of vaccines and simultaneously create a novel testbed for future vaccine developments, accelerating the pace of innovation."

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

The researchers also conducted a direct comparative study, evaluating a DoriVac vaccine designed to present the full SARS-CoV-2 spike protein. This crucial comparison, led by Zeng and co-author Qiancheng Xiong, pitted the DoriVac platform against commercially available mRNA lipid nanoparticle (LNP) vaccines from Moderna and Pfizer/BioNTech, which encode the identical spike protein sequence.

Utilizing a standard booster approach in mouse models, the results demonstrated a remarkable parity: both vaccine types produced similarly strong antiviral T cell and antibody-producing B cell responses. This finding is highly significant, as it suggests that DoriVac can achieve the same level of immunological potency as the gold-standard mRNA vaccines, but potentially with distinct practical advantages.

"This underscored DoriVac’s potential as a DNA nanotechnology-enabled, self-adjuvanted vaccine platform, matching the immune activation capabilities of established mRNA vaccines," commented William Shih. He further highlighted DoriVac’s numerous other benefits: "DoriVac vaccines do not have the same stringent cold-chain requirements as mRNA-LNP vaccines do, and thus could be distributed much more effectively, especially in under-resourced regions of the world where refrigeration is a major hurdle. Moreover, they could overcome some of the enormous manufacturing complexities of LNP-formulated vaccines, to name two major ones." The implications of ambient temperature stability and simplified production for global vaccine equity and pandemic preparedness are immense. Recent studies conducted at DoriNano have also provided promising data regarding DoriVac’s safety profile, further bolstering its potential for clinical translation.

Broader Implications and Future Outlook

The emergence of the DoriVac platform represents a significant step forward in the ongoing quest for more effective, accessible, and resilient vaccine technologies. Its ability to match the immune potency of mRNA vaccines while offering superior stability, simplified storage, and potentially easier manufacturing could revolutionize global health strategies. For low- and middle-income countries, the elimination of ultra-cold chain requirements alone could dramatically improve vaccine accessibility and uptake, fostering greater equity in public health outcomes worldwide.

The inherent versatility of the DNA origami chassis also positions DoriVac as a highly adaptable platform. Its modular design allows for rapid swapping of antigens, making it a promising candidate for swift responses to future pandemics and for developing vaccines against a wide array of existing infectious diseases, including those for which current vaccine options are limited or nonexistent. The initial success in targeting conserved regions like HR2 across multiple viruses (SARS-CoV-2, HIV, Ebola) hints at the possibility of developing pan-viral vaccines that offer broad protection against entire families of pathogens.

While these findings are currently in the preclinical stage, the robust data from both mouse models and human organ-on-a-chip systems provide a strong foundation for advancing DoriVac towards human clinical trials. The next critical steps will involve rigorous safety assessments and efficacy studies in human volunteers, which will ultimately determine its real-world impact. The multidisciplinary collaboration that brought DoriVac to fruition—drawing on nanotechnology, immunology, bioengineering, and virology—exemplifies the power of convergent science in addressing humanity’s most pressing health challenges. As the world continues to grapple with existing and emerging infectious threats, platforms like DoriVac offer a beacon of hope for a future where vaccines are not only highly effective but also universally accessible.

The study’s extensive author list includes 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. Funding for this pivotal research was generously provided by a consortium of institutions, including 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), underscoring the global importance and collaborative spirit behind this innovative vaccine technology.