Search

Multi-responsive nanomaterials based on the self-limited assembly of plasmonic nanoparticles are of great interest due to their widespread employment in sensing applications. We present a thorough investigation of a hybrid nanomaterial based on the protein-mediated aggregation of gold nanoparticles at varying protein concentration, pH and temperature. By combining Small Angle X-ray Scattering with extinction spectroscopy, we are able to frame the morphological features of the formed fractal aggregates in a theoretical model based on patchy interactions. Based on this, we established the main factors that determine the assembly process and their strong correlation with the optical properties of the assemblies. Moreover, the calibration curves that we obtained for each parameter investigated based on the extinction spectra point out to the notable flexibility of this nanomaterial, enabling the selection of different working ranges with high sensitivity. Our study opens for the rational tuning of the morphology and the optical properties of plasmonic assemblies to design colorimetric sensors with improved performances. [ABSTRACT FROM AUTHOR]

Coherent random lasers (RLs) originate from the resonant amplification of the light scattered by disordered media resulting in spiky emission spectra with well‐defined spectral signatures. Here coherent RL emission is proposed as a tool for identifying the spectral fingerprint of porous micro‐structured materials obtained by soft lithography techniques. The close control of the spatial patterns and structural characteristics of the scattering elements enable us to obtain stable and unique RL spectra distinctive of each lithographed device. The spectral emission has been thoroughly analyzed with respect to the morphology of the devices in terms of surface roughness and surface volume fraction, demonstrating that the packing of the scattering particles is the main factor in determining a RL emission characterized by multiple linewidths with a high level of coherence. The findings provide novel insights for the realization of miniaturized photonic devices with selectable optical features. [ABSTRACT FROM AUTHOR]

We realise an antibacterial nanomaterial based on the self-limited assembly of patchy plasmonic colloids, obtained by adsorption of lysozyme to gold nanoparticles. The possibility of selecting the size of the assemblies within several hundred nanometres allows for tuning their optical response in a wide range of frequencies from visible to near infrared. We also demonstrate an aggregation-dependent modulation of the catalytic activity, which results in an enhancement of the antibacterial performances for assemblies of the proper size. The gained overall control on structure, optical properties and biological activity of such nanomaterial paves the way for the development of novel antibacterial nanozymes with promising applications in treating multi drug resistant bacteria. [ABSTRACT FROM AUTHOR]