Artificial ciliary bundles with nano fiber tip links

TL;DR

This paper presents the design and fabrication of ultrasensitive MEMS flow sensors inspired by fish ciliary bundles, incorporating nano-fiber tip links and a hydrogel cupula to mimic biological sensing mechanisms.

Contribution

It introduces a novel artificial ciliary bundle with nano-fiber tip links and a hydrogel cupula, achieving biological-level sensitivity in flow detection.

Findings

Threshold detection limits match biological examples

Nano-fiber tip links generate measurable charges under fluid flow

Artificial ciliary bundle demonstrates high sensitivity to fluid drag forces

Abstract

Mechanosensory ciliary bundles in fishes are the inspiration for carefully engineered artificial flow sensors. We report the development of a new class of ultrasensitive MEMS flow sensors that mimic the intricate morphology of the ciliary bundles, including the stereocilia, tip links, and the cupula, and thereby achieve threshold detection limits that match the biological example. An artificial ciliary bundle is achieved by fabricating closely-spaced arrays of polymer micro-pillars with gradiating heights. Tip links that form the fundamental sensing elements are realized through electrospinning aligned PVDF piezoelectric nano-fibers that link the distal tips of the polymer cilia. An optimized synthesis of hyaluronic acid-methacrylic anhydride hydrogel that results in properties close to the biological cupula, together with drop-casting method are used to form the artificial cupula that encapsulates the ciliary bundle. In testing, fluid drag force causes the ciliary bundle to slide, stretching the flexible nanofibers, thus eliciting charges.