From Biological Cilia to Artificial Flow Sensors: Biomimetic Soft Polymer Nanosensors with High Sensing Performance.
We report the development of a new class of miniature all-polymer flow sensors that closely mimic the intricate morphology of the mechanosensory ciliary bundles in biological hair cells. An artificial ciliary bundle is achieved by fabricating bundled polydimethylsiloxane (PDMS) micro-pillars with graded heights and electrospinning polyvinylidenefluoride (PVDF) piezoelectric nanofiber tip links. The piezoelectric nature of a single nanofiber tip link is confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Rheology and nanoindentation experiments are used to ensure that the viscous properties of the hyaluronic acid (HA)-based hydrogel are close to the biological cupula. A dome-shaped HA hydrogel cupula that encapsulates the artificial hair cell bundle is formed through precision drop-casting and swelling processes. Fluid drag force actuates the hydrogel cupula and deflects the micro-pillar bundle, stretching the nanofibers and generating electric charges. Functioning with principles analogous to the hair bundles, the sensors achieve a sensitivity and threshold detection limit of 300 mV/(m/s) and 8 μm/s, respectively. These self-powered, sensitive, flexible, biocompatibale and miniaturized sensors can find extensive applications in navigation and maneuvering of underwater robots, artificial hearing systems, biomedical and microfluidic devices.
School of Mechanical &Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.|Department of Engineering, Macquarie University, Sydney, New South Wales 2109, Australia.
Mohsen
M
Asadnia
Center for Environmental Sensing and Modeling (CENSAM) IRG Singapore-MIT Alliance for Research and Technology (SMART) Centre, 3 Science Drive 2, 117543 Singapore.
Ajay Giri Prakash
AG
Kottapalli
Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
K Domenica
KD
Karavitaki
School of Mechanical and Manufacturing Engineering, Australian Centre for NanoMedicine, University of New South Wales, Sydney, New South Wales 2052, Australia.
Majid Ebrahimi
ME
Warkiani
School of Mechanical &Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
Jianmin
J
Miao
Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
David P
DP
Corey
Center for Environmental Sensing and Modeling (CENSAM) IRG Singapore-MIT Alliance for Research and Technology (SMART) Centre, 3 Science Drive 2, 117543 Singapore.|Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Michael
M
Triantafyllou
D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D040761:Biomimetic Materials / Q000737:chemistry*; D015374:Biosensing Techniques; D002923:Cilia / Q000502:physiology; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004867:Equipment Design; D006198:Hair Cells, Auditory / Q000502:physiology; D020100:Hydrogels; D055595:Mechanical Phenomena; D040542:Mechanotransduction, Cellular / Q000502:physiology; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D057139:Nanofibers / Q000737:chemistry*; D036103:Nanotechnology; D011145:Polyvinyls / Q000737:chemistry; D012212:Rheology / Q000295:instrumentation; D005465:Fluorocarbon Polymers
D001672:Biocompatible Materials; D004129:Dimethylpolysiloxanes; D020100:Hydrogels; D011145:Polyvinyls; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers