Aging Mammalian Tissues In Vitro (R21 Clinical Trial Not Allowed) | RFA AG 26 014

Opportunity Information: Apply for RFA AG 26 014

The NIH funding opportunity titled "Aging Mammalian Tissues In Vitro (R21 Clinical Trial Not Allowed)" (RFA-AG-26-014) supports exploratory, early-stage research aimed at building and refining sophisticated 3D in vitro microphysiological systems (MPS) that can model mammalian aging. The central goal is to create lab-based tissue and organ models that do more than mimic basic biology; they should reproduce key aging processes and measurable aging-related phenotypes that are typically observed in living organisms. The program is designed to push the field toward more realistic, human-relevant aging models that can be used both to study aging mechanisms and to improve drug discovery by providing better preclinical testing platforms than traditional cell culture systems.

The NOFO is primarily focused on MPS made from human cells, including platforms such as tissue chips, organs-on-chips, and tissue organoids. That said, nonhuman mammalian cell-based systems are still acceptable in specific roles, such as benchmarking against human systems, validating that the platform behaves as intended, or in cases where the applicant can make a clear argument that the nonhuman model is directly informative for understanding human aging biology. In practical terms, the funding aims to accelerate the adoption of these systems by the broader aging research community, encouraging tools that are robust, reproducible, and biologically meaningful for aging research and translational applications.

This opportunity uses the NIH R21 mechanism, which is intended for high-risk, high-reward exploratory projects that are still at a conceptual or early developmental stage. A key implication is that preliminary data are not required, which lowers the barrier for teams proposing innovative approaches that have not yet been extensively validated. The work is not intended to be clinical research, and clinical trials are explicitly not allowed under this announcement.

A defining requirement for competitive applications is a genuinely multidisciplinary approach. The NOFO emphasizes that responsive projects should integrate expertise in aging biology along with capabilities from areas such as stem cell biology, tissue and organ physiology, microfluidics, bioengineering, computational biology, pharmacology, and biostatistics. This reflects the reality that modeling aging in vitro is not a single-discipline problem: it involves engineering stable long-term culture environments, recreating tissue-level structure and function, capturing age-associated cellular and molecular changes, and analyzing complex multi-parameter data in a way that supports credible claims about aging phenotypes and intervention effects.

Eligibility is broad across U.S.-based organizations and includes many government entities and academic and non-academic research performers. Eligible applicants include state, county, and city or township governments; special district governments; independent school districts; public and state-controlled institutions of higher education; private institutions of higher education; federally recognized Native American tribal governments; other Native American tribal organizations; public housing authorities/Indian housing authorities; nonprofits with or without 501(c)(3) status (excluding institutions of higher education when specified by category); for-profit organizations other than small businesses; and small businesses. The announcement also notes eligibility for certain additional categories such as eligible federal agencies, faith-based or community-based organizations, regional organizations, U.S. territories or possessions, and Indian/Native American tribal governments that are not federally recognized.

Foreign organizations are not eligible to apply, and non-domestic components of U.S. organizations are not eligible to apply as components. However, "foreign components" as defined by the NIH Grants Policy Statement are allowed, meaning a U.S. applicant may include certain types of foreign collaborations or activities when they meet NIH policy definitions and requirements. The funding instrument is a grant, and the activity category is health (CFDA 93.866). The original closing date listed is 2025-10-20, and the opportunity was created on 2025-08-26. The provided source text does not specify an award ceiling or the expected number of awards, indicating those details may be posted elsewhere in the full announcement or in NIH budget guidance for the R21 mechanism.

Overall, the program is best read as an NIH push to move aging research toward next-generation, human-relevant experimental systems that can reproduce meaningful aspects of aging in a controlled, engineered setting. Applicants are being invited to take early, creative steps toward platforms that make aging biology easier to measure, manipulate, and translate into therapeutic discovery, while building the interdisciplinary teams needed to make those platforms credible and usable by others.

• The National Institutes of Health in the health sector is offering a public funding opportunity titled "Aging Mammalian Tissues In Vitro (R21 Clinical Trial Not Allowed)" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 93.866.
• This funding opportunity was created on 2025-08-26.
• Applicants must submit their applications by 2025-10-20. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• Eligible applicants include: State governments, County governments, City or township governments, Special district governments, Independent school districts, Public and State controlled institutions of higher education, Native American tribal governments (Federally recognized), Public housing authorities/Indian housing authorities, Native American tribal organizations (other than Federally recognized tribal governments), Nonprofits having a 501 (c) (3) status with the IRS, other than institutions of higher education, Nonprofits that do not have a 501 (c) (3) status with the IRS, other than institutions of higher education, Private institutions of higher education, For-profit organizations other than small businesses, Small businesses, Others.

Apply for RFA AG 26 014

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