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Control viscoelástico del orden espacio-temporal en la materia activa bacteriana
Song Liu1, Suraj Shankar2,3,4, M Cristina Marchetti5
1Department of Physics and Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, P. R. China.
Nature
|February 4, 2021
Resumen
Los investigadores controlaron la autoorganización de la materia activa bacteriana mediante la alteración de la viscoelasticidad del fluido. Esto creó un vórtice oscilante sintonizable, que ofrece nuevas formas de dirigir los flujos de materia activa y desarrollar aplicaciones robóticas blandas.
Área de la Ciencia:
- Física de la materia activa
- Robótica suave
- Microbiología
Sus antecedentes:
- Los sistemas de materia activa, incluidas las bacterias, exhiben una autoorganización compleja, que a menudo muestra orden espacial o sincronización temporal.
- Controlar simultáneamente la organización espacial y temporal en la materia activa generalmente requiere interacciones complejas o sistemas de ingeniería.
- Comprender y controlar la dinámica de la materia activa es crucial para aplicaciones que van desde sistemas biológicos hasta robótica suave.
Objetivo del estudio:
- Desarrollar una técnica sencilla para controlar simultáneamente la autoorganización espacial y temporal de la materia activa bacteriana.
- Investigar la influencia de la viscoelasticidad del fluido en el comportamiento colectivo de las suspensiones bacterianas.
- Demostrar un nuevo método para aprovechar las propiedades reológicas para dirigir los flujos de materia activa.
Principales métodos:
- Suspensiones densas confinadas de Escherichia coli (un tipo de bacteria).
- Manipuló la viscoelasticidad del fluido añadiendo ADN genómico purificado.
- Observaciones experimentales combinadas con un modelo de materia activa para analizar el comportamiento.
Principales resultados:
- Logró una autoorganización espacial y temporal simultánea, manifestándose como un vórtice giratorio a escala milimétrica.
- Oscilaciones periódicas observadas en la quiralidad global con frecuencia sintonizable, parecidas a un péndulo de torsión.
- Explicó la dinámica del vórtice a través de la interacción del forzamiento activo y la relajación de la tensión viscoelástica.
Conclusiones:
- Se ha demostrado que un solo parámetro macroscópico (viscoelasticidad del fluido) puede controlar la autoorganización de la materia activa compleja.
- Los hallazgos ofrecen información sobre el comportamiento bacteriano en fluidos complejos con potencial de salud y relevancia ecológica.
- El vórtice bacteriano sintonizable y autooscilante se puede imaginar como un "generador de reloj" para robots blandos y dispositivos microfluídicos.
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