Combining 2D organic and 1D inorganic nanoblocks to develop free-standing hybrid nanomembranes for conformable biosensors

Jose García-Torres,Carmen Lázaro,Dioulde Sylla,Sonia Lanzalaco,Maria-Pau Ginebra,Carlos Alemán

doi:10.1007/s40097-022-00482-5

Abstract

We report a simple approach to fabricate free-standing perforated 2D nanomembranes hosting well-ordered 1D metallic nanostructures to obtain hybrid materials with nanostructured surfaces for flexible electronics. Nanomembranes are formed by alternatively depositing perforated poly(lactic acid) (PLA) and poly(3,4-ethylenedioxythiophene) layers. Copper metallic nanowires (NWs) were incorporated into the nanoperforations of the top PLA layer by electrodeposition and further coated with silver via a transmetallation reaction. The combination of 2D polymeric nanomembranes and aligned 1D metallic NWs allows merging the flexibility and conformability of the ultrathin soft polymeric nanomembranes with the good electrical properties of metals for biointegrated electronic devices. Thus, we were able to tailor the nanomembrane surface chemistry as it was corroborated by SEM, EDX, XPS, CV, EIS and contact angle. The obtained hybrid nanomembranes were flexible and conformable showing sensing capacity towards H2O2 with good linear concentration range (0.35–10 mM), sensitivity (120 µA cm−2 mM−1) and limit of detection (7 μm). Moreover, the membranes showed good stability, reproducibility and selectivity towards H2O2.

Highlights

Flexible electronics have been extensively researched during the last decade over conventional rigid electronics due to their capacity to be integrated onto complex, curved or time dynamic surfaces like biological tissues and organs [1, 2]
While the poly(lactic acid) (PLA) layers conferred mechanical stability and contained the nanoperforations to host the nanostructures, PEDOT layers were used for their electrical properties
A nanoperforated PLA layer was obtained by spin coating using a PLA/poly(vinyl alcohol) (PVA) 90:10 v/v solution following the selective PVA etching in water creating the nanoperforations

Summary

Introduction

Flexible electronics have been extensively researched during the last decade over conventional rigid electronics due to their capacity to be integrated onto complex, curved or time dynamic surfaces like biological tissues and organs [1, 2]. The 2D nanomembranes show high macroscopic surface area and nanometric thickness (aspect ratio > 1 06) which enables their macroscopic use in a free-standing way as their mechanical integrity/robustness is retain These nanomembranes have high flexibility because, according to the Euler–Bernoulli beam theory, the rigidity of a material, that is the resistance to bending, is proportional to its thickness to the third power [13]. They theoretically demonstrated that the critical value for their elastomeric membranes was ⁓ 25 μm and they successfully experimentally proved that membranes thinner than this value perfectly conformed onto skin [14] Apart from those properties, nanomembranes have attracted great attention due to the possibility to tune their architecture from single layered to multilayered nanomembranes and with or without (nano)perforations. Such variability has allowed expanding their applicability range like the transport of metabolites through the nanomembranes, soft actuators, water remediation or biointerfaces as cell matrixes [15–18]

Methods

Results

Conclusion