Bio-Templating in Asteroid Ryugu Material: Structural Evidence for Fossilized Wood-Like Nanofibrils

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Abstract

High-resolution transmission electron microscopy (TEM) of particle C0068 from asteroid Ryugu reveals regularly spaced nano-lamellae with lattice fringes measuring approximately 0.7 nm and 1.1 nm. While the original interpretation identifies these as saponite–serpentine intergrowths, we propose an alternative explanation: the observed nanostructures more accurately resemble biogenic wood fibrils templated by preexisting cellular architecture. Comparative morphology with Earthly wood tissues shows alignment, periodicity, and strand formation consistent with secondary cell wall structure, particularly that of the S2 layer. This article presents structural, mineralogical, and morphological evidence supporting the hypothesis that the observed Ryugu nanofibrils may be fossilized wood-like elements formed through bio-templating.

Introduction

Samples retrieved from asteroid Ryugu by JAXA’s Hayabusa2 mission offer a unique window into prebiotic and potentially biogenic materials in the early solar system. Particle C0068, a thin-sectioned sample analyzed with TEM and energy-dispersive spectroscopy (EDS), exhibits ultrastructural features that raise compelling questions about its origin. Among these is Figure 1c from Nature Astronomy (DOI: 10.1038/s41550-022-01745-5), which reveals lattice-scale banding of alternating 0.7 nm and 1.1 nm fringes. The current mineralogical interpretation assigns these to intergrown saponite and serpentine. However, this article evaluates whether these features better match the architecture of fossilized wood-like fibrils.

Results

1. Nano-lamellar Features

In Figure 1c (reproduced in this article), numerous red arrows and rectangles mark vertical, longitudinally aligned fibrils that measure between 0.7 nm and 1.1 nm in periodicity. The fibrils are connected end-to-end and side-by-side, forming linear bundles that resemble the elementary fibrils in the S2 wall layer of Earthly tracheids.

2. Evidence of Spatial Continuity and Reduced Complexity

One green rectangle in the lower center of Figure 1c highlights an area where the fibrils are less densely organized, suggesting either degradation or early-stage formation. A blue rectangle and blue arrow mark spatial continuity between individual fibrils. These visual patterns support the idea of templating, where mineral phases replicate the form of an original organic matrix.

Comparative Analysis

Figure 2 presents a multiscale schematic of terrestrial wood cell wall architecture. It illustrates the arrangement of tracheids, layered secondary walls (S1, S2, S3), and nanoscale components such as lignin, xylan, and glucomannan. The elementary fibrils in the S2 layer exhibit nanostructures with spacing and organization comparable to those seen in Figure 1c.

Feature	Ryugu C0068 (Fig. 1c)	Earth Wood S2 Layer (Fig. 2)
Lattice fringe spacing	0.7 nm / 1.1 nm	0.7–1.2 nm
Orientation	Vertical, aligned strands	Longitudinal fibril bundles
Connection pattern	Side-to-side and end-to-end	Endwise-connected vessels
Structural complexity	Moderate to reduced	Complex but patterned

Discussion

While saponite and serpentine are common in carbonaceous chondrites, there is no known abiotic process that yields rhythmically alternating lamellae of both minerals at nanometer precision in the form observed in Ryugu sample C0068. The rhythmicity, vertical alignment, and template-consistent structure of the fibrils are all characteristic of biologically derived material. These features, especially their strand-like continuity and regular inter-fibril spacing, mirror the ultrastructure of terrestrial xylem.

Biological templating, or bio-templating, is a process by which biological material serves as a framework for mineralization. The evidence in C0068 suggests such a mechanism may have preserved wood-like nano-architecture through mineral infiltration and replacement.

Conclusion

The Ryugu particle C0068 contains nanoscale fibrils that are structurally, dimensionally, and morphologically consistent with fossilized wood cells. Rather than simple mineral intergrowth, these features may reflect the templated preservation of biological cell wall structures, possibly derived from a parent body such as Mars. This bio-templating interpretation opens avenues for re-examining other asteroidal and meteoritic materials for signs of fossilized life.

References

1. Nakamura, T. et al. (2022). Formation and alteration history of the C-type asteroid Ryugu: Direct evidence from returned samples. Nature Astronomy. https://doi.org/10.1038/s41550-022-01745-5

2. Donaldson, L. (2007). Cell wall structure of tracheids in Pinus radiata. IAWA Journal, 28(2), 173–184.

3. Singh, A. P. et al. (2002). Structure and function of lignin in plants. Annals of Botany, 90(3), 301–311.

4. Lin, L. (2025). Evidence of Fossilized Wood-Like Ultrastructure in Asteroid Ryugu Material. ResearchGate. https://www.researchgate.net/publication/393976978

5. Lin, L. (2025). Bio-templating from Asteroid Ryugu. Wretch Fossil. https://wretchfossil.blogspot.com/2025/07/bio-templating-from-asteroid-ryugu.html

  

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Source: https://wretchfossil.blogspot.com/2025/07/bio-templating-in-asteroid-ryugu.html