Self‐assembly of mechanoplasmonic bacterial cellulose–metal nanoparticle composites

Nanocomposites of metal nanoparticles (NPs) and bacterial nanocellulose (BC) enable fabrication of soft and biocompatible materials for optical, catalytic, electronic, and biomedical applications. Current BC–NP nanocomposites are typically prepared by in situ synthesis of the NPs or electrostatic adsorption of surface functionalized NPs, which limits possibilities to control and tune NP size, shape, concentration, and surface chemistry and influences the properties and performance of the materials. Here a self‐assembly strategy is described for fabrication of complex and well‐defined BC–NP composites using colloidal gold and silver NPs of different sizes, shapes, and concentrations. The self‐assembly process results in nanocomposites with distinct biophysical and optical properties. In addition to antibacterial materials and materials with excellent senor performance, materials with unique mechanoplasmonic properties are developed. The homogenous incorporation of plasmonic gold NPs in the BC enables extensive modulation of the optical properties by mechanical stimuli. Compression gives rise to near‐field coupling between adsorbed NPs, resulting in tunable spectral variations and enhanced broadband absorption that amplify both nonlinear optical and thermoplasmonic effects and enables novel biosensing strategies.This work was supported by the Swedish Foundation for Strategic Research (SFF) grant no. FFL15‐0026 and framework grant RMX18‐0039 (HEALiX), the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO‐Mat‐LiU no. 2009‐00971), the competence center FunMat‐II that is financially supported by Vinnova (grant no. 2016‐05156), and the Knut and Alice Wallenberg Foundation (grant no. KAW 2016.0231), the Swedish Research Council (grant Nos. 2017‐05178 and 2015‐05002) and the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN) through the MAT2016‐77391‐R. The ICN2 was supported by the Severo Ochoa Centres of Excellence programme, funded by the Spanish Research Agency (AEI, grant no. SEV‐2017‐0706).Peer reviewe