Priority research questions in microbiome-integrated urban design

Abstract

Urbanization is accelerating at an unprecedented pace, with 70% of the global population projected to live in cities by 2050. This shift presents significant challenges and opportunities for fostering sustainable urban ecosystems aligned with the United Nations Sustainable Development Goals. Microbiomes-the diverse communities of microorganisms that underpin ecosystem function-are increasingly recognized for their vital role in nutrient cycling, climate regulation, biodiversity support, and human well-being. However, their consideration and integration in urban design remain underexplored, often limited to disease mitigation. The emerging field of microbiome-integrated urban design seeks to leverage microbial activity to enhance urban health and resilience through a multispecies framework. To address critical gaps, the Probiotic Cities Working Group convened a global interdisciplinary workshop, engaging experts from ecology, architecture, urban planning, immunology, and social sciences. Using reverse brainstorming and thematic analysis, participants identified eight core themes and 40 priority research questions (via a modified Delphi technique). These themes span communication and policy, pollution prevention, interdisciplinary collaboration, experimental design, ethics, and public perception of microbiomes. A binomial concordance analysis revealed strong consensus on the top-ranked questions, which address urgent needs such as improving science communication, defining success metrics, and promoting evidence-based microbiome interventions. This paper discusses the top-ranked priority research questions and their broader implications for microbiome science, urban health, and sustainable development. By focusing on these priorities, researchers, policymakers, and practitioners can foster a transformative agenda to integrate microbiomes into urban design, advancing resilient and equitable cities for the future.

Keywords: bioaugmented design; biodesign; biointegrated design; microbiome; urban ecology.

Fig 1

Disciplines involved in the workshop and a workflow showing the process of generating the priority research questions.

Fig 2

Venn diagram showing the eight interconnected microbiome-integrated urban design research themes identified during the thematic analysis.

Fig 3

Examples of indoor bio-augmented materials that integrate living or microbial-compatible systems into design. Top left: bio-integrated wall system combining structural substrate with cascading vegetation to support plant-microbiome interactions indoors. Top right: 3D-printed modular structures inspired by natural forms (e.g., coral and fungi), designed as porous habitats that can host microbial and plant life. Bottom left: experimental wall cladding with patterned micro-reservoirs for moss and microbial colonization, enabling living green surfaces in controlled indoor environments. Bottom right: close-up of a bio-textile surface designed for tactile interaction, with inset scanning electron micrograph showing microbial colonization at the microscale (of the beneficial Bacillus subtilis).