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La basicidad de aminas (pKb) controla la energía de unión del analito en las matrices de sensores electrónicos de
Chang Young Lee1, Michael S Strano
1Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Journal of the American Chemical Society
|January 15, 2008
Resumen
Los investigadores crearon sitios de adsorción reversibles en matrices de sensores de nanotubos de carbono de pared única (SWNT) utilizando la funcionalización de aminas. Este avance permite una detección altamente sensible y reversible de analitos a nivel de partes por billón sin regeneración.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Nanotecnología La nanotecnología es la nanotecnología.
- Sensores químicos de detección de sustancias químicas.
Sus antecedentes:
- Las redes de nanotubos de carbono de pared única (SWNT) son ampliamente utilizadas en sensores y transistores electrónicos.
- La adsorción irreversible del analito en las superficies SWNT limita sus aplicaciones de detección.
- El mecanismo subyacente de esta adsorción irreversible sigue siendo poco conocido.
Objetivo del estudio:
- Comprender y controlar los mecanismos de adsorción de analito en SWNTs.
- Para diseñar superficies SWNT para la unión reversible del analito.
- Desarrollar sensores altamente sensibles y reutilizables basados en SWNT.
Principales métodos:
- Funcionalización no covalente de matrices SWNT con moléculas terminadas en aminas.
- Utilizando el cloruro de tionilo como adsorbado modelo para estudiar la adsorción.
- Caracterización mediante espectroscopia de fotoelectrones de rayos X (XPS) y cálculos del potencial molecular.
- Probar varias moléculas que contienen aminas y aminas poliméricas como la polietilenoimina (PEI).
Principales resultados:
- Se crearon con éxito sitios de adsorción reversibles en matrices SWNT a través de la funcionalización de aminas (pKa < 8.8).
- La adsorción del analito está significativamente influenciada por la basicidad (pKb) de los grupos de aminas superficiales.
- Se identificó un mecanismo de adsorción mediada, que reduce la energía de unión, y fue apoyado por XPS y cálculos.
- Se logró la detección reversible a nivel de partes por billón utilizando la funcionalización de polietilenoimine (PEI) sin regeneración activa.
Conclusiones:
- La funcionalización de la superficie con moléculas de aminas específicas permite la adsorción reversible del analito en SWNTs.
- Este mecanismo de adsorción mediada es un fenómeno general aplicable a varios diseños de sensores basados en SWNT.
- El método desarrollado mejora significativamente la reutilización y la sensibilidad de los sensores SWNT para la detección de trazas de analito.
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