科学者たちは、ヤモリの接着の仕組みをすでに理解していた。今回、ヤモリにグリップ力を与えている分子構造について、より明確な知見を得ることができた。 Scientists already understood the mechanics of gecko adhesion. Now they have a clearer picture of the molecular structures that give the animal its grip.
2022-07-06 アメリカ国立標準技術研究所(NIST)
米国国立標準技術研究所(NIST)の研究者たちは、シンクロトロンと呼ばれる粒子加速器の一種が発する高エネルギーX線を用いて、歯根の表面を分析した。シンクロトロン顕微鏡で観察したところ、葉身の表面に脂質分子が規則正しく密集して並んでいることが確認された。
この研究成果は、国際研究チームによって『Biology Letters』誌に発表された。また、『Physical Chemistry Letters』誌に掲載された先行論文では、同じ手法で、鞭毛を構成する個々のタンパク質鎖がどのように配列しているかが示されている。
<関連情報>
- https://www.nist.gov/news-events/news/2022/07/gecko-feet-are-coated-ultra-thin-layer-lipids-help-them-stay-sticky
- https://royalsocietypublishing.org/doi/10.1098/rsbl.2022.0093
- https://pubs.acs.org/doi/full/10.1021/acs.jpclett.2c00004
ヤモリの顎足がナノメートルオーダーの薄い脂質膜で覆われていることの証拠 Evidence that gecko setae are coated with an ordered nanometre-thin lipid film
Mette H. Rasmussen,Katinka Rønnow Holler,Joe E. Baio,Cherno Jaye,Daniel A. Fischer,Stanislav N. Gorb and Tobias Weidner
Biology Letters Published:06 July 2022
DOI:https://doi.org/10.1098/rsbl.2022.0093
Abstract
The fascinating adhesion of gecko to virtually any material has been related to surface interactions of myriads of spatula at the tips of gecko feet. Surprisingly, the molecular details of the surface chemistry of gecko adhesion are still largely unknown. Lipids have been identified within gecko adhesive pads. However, the location of the lipids, the extent to which spatula are coated with lipids, and how the lipids are structured are still open questions. Lipids can modulate adhesion properties and surface hydrophobicity and may play an important role in adhesion. We have therefore studied the molecular structure of lipids at spatula surfaces using near-edge X-ray absorption fine structure imaging. We provide evidence that a nanometre-thin layer of lipids is present at the spatula surfaces of the tokay gecko (Gekko gecko) and that the lipids form ordered, densely packed layers. Such dense, thin lipid layers can effectively protect the spatula proteins from dehydration by forming a barrier against water evaporation. Lipids can also render surfaces hydrophobic and thereby support the gecko adhesive system by enhancement of hydrophobic–hydrophobic interactions with surfaces.
近接場X線吸収微細構造分光法によるヤモリの付着器中のケラチンの構造決定 Structure of Keratins in Adhesive Gecko Setae Determined by Near-Edge X-ray Absorption Fine Structure Spectromicroscopy
Katinka Rønnow Holler,Mette A. Rasmussen, Joe E. Baio, Cherno Jaye, Daniel A. Fischer, Stanislav N. Gorb, and Tobias Weidner*
Physical Chemistry Letters Published:March 1, 2022
DOI:https://doi.org/10.1021/acs.jpclett.2c00004
Abstract
Geckos have the astonishing ability to climb on vertical surfaces due to the adhesive properties of fibrous setae at the tips of their toe pads. While the adhesion mechanism principle, based on van der Waals interactions of myriads of spatula located at the outermost end of the setal arrays, has been studied extensively, there are still open questions about the chemistry of gecko setae. The gecko adhesive system is based on keratin fibrils assembled to support the entire setal structure. At the same time, the structure and alignment of keratin molecules within the ultrafine spatula tissue, which can support the enormous mechanical strain, still remain unknown. We have studied the molecular structure of gecko spatula using near-edge X-ray absorption fine structure (NEXAFS) imaging. We indeed found that the setae consist of a β-sheet structure aligned with the adhesion direction of the setae. Such alignment may provide mechanical stability to the setae and resistance to wear across different length scales.
