Thin Graphene Oxide Nanosheets Safe for Human Inhalation in First Controlled Clinical Trial

Thin Graphene Oxide Nanosheets Safe for Human Inhalation in First Controlled Clinical Trial

Graphene oxide has generated substantial interest globally with applications in electronics, energy, medicine, and more. However, uncertainties around the human health impacts of manufactured nanomaterials have raised safety concerns over widespread use.

Graphene oxide (GO) is a unique two-dimensional nanomaterial derived from graphene, the world’s thinnest and strongest known material. The University of Edinburgh has released a paper on the first controlled clinical trial examining the acute effects of inhaled thin graphene oxide sheets on respiratory and cardiovascular function measures in human volunteers, and the results are encouraging for the future of this ground-breaking material.

Are Graphene Oxide Nanosheets Safe For Humans?

The graphene oxide sheets used in this study were carefully synthesized to tight specifications at the nanoscale. Two sizes of sheets were tested: “small” GO sheets with a 370 nm mean lateral dimension and “ultrasmall” GO sheets with a 178 nm mean size. Otherwise, the materials had near-identical thickness, functional groups, and contaminant levels.

Graphene Oxide Nanosheets

In the randomized controlled trial, 14 healthy volunteers visited on 3 separate occasions to inhale either small GO, ultrasmall GO, or filtered air (control) for 2 hours under closely monitored conditions. Lung function, cardiovascular vital signs, blood cell counts, clotting factors, inflammatory markers, and other clinical measures were assessed at baseline and multiple times during exposure.

Acute GO exposure did not lead to self-reported symptoms or change lung function as measured by spirometry. Key indicators like blood pressure and heart rate showed no worrisome effects either. Further, no concerning inflammatory or white blood cell responses were found. GO exposure mildly impacted coagulation in the ex vivo thrombosis model. However, traditional clotting time tests were unchanged. Ultrasmall and small GO produced highly similar clinical results. The materials were effectively indistinguishable in terms of acute cardiorespiratory effects and tolerability. Across all tests, thin GO exposure elicited only minor biological responses compared to control.

This first-of-its-kind study demonstrates the safety of controlled acute exposure to highly pure, nanoscale thin GO sheets. The results should assuage concerns over adverse effects from unintended occupational-level inhalation. They also pave the way for intentionally administering GO via inhalation, whether for drug delivery or other nanomedicine applications.

While extended exposures may produce different outcomes, the current findings provide a baseline understanding of thin GO’s impact on human health. The study establishes the feasibility of tightly controlled GO inhalation trials, enabling future work to methodically assess different sheet sizes, purities, doses, and exposure durations. Such research will elucidate the properties and paradigms for the safe-by-design development of this versatile nanomaterial.

The study is vital because it shows that graphene oxide’s potential could be unlocked without risking human well-being.


  • The first controlled trial finds highly pure, nanoscale thin graphene oxide sheets safe for human inhalation
  • Two-hour exposures elicited no concerning effects on lung function, vital signs, or inflammatory markers
  • Results positive for occupational hazard assessment and biomedical applications via inhalation
  • Further studies are still needed on different graphene oxide materials and exposure conditions
  • Demonstrates feasibility of controlled graphene oxide inhalation trials in humans
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