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The adhesion and formation of microbial biofilm on material surfaces is a relevant problem in many areas including in medicine and biomaterials engineering. Biofilms are the primary cause of persistent infections associated with biomedical devices and clinical settings due to their tolerance and resistance to antimicrobial treatment. Reducing initial bacterial attachment to surfaces could decrease the formation of biofilms and, consequently, the posterior dispersion stage in which bacteria present within biofilms expand to other regions, spreading the infection. In this context, the use of surface topography to minimize microbial infections and biofilm formation represents an emerging area of research as it tackles this problem without the need to use antibiotics or other chemical agents. Herein, we review recent progress in surface topography-based antimicrobial approaches and provide an overview of the influence of micro- and nano-topography on bacterial surface attachment. We focus primarily on structured polymeric surfaces. The versatility and properties of polymer materials, along with their propensity to standardization at different length scales, make them an excellent option for fabrication of numerous medical devices. This work also provides a brief overview of recent advances in patterning polymers using lithography, direct-write patterning techniques, and instability-induced patterning. The impact of micro-, nano- and hierarchical surface structuration on the antimicrobial response of polymeric surfaces is addressed to offer new insights for the preparation of antimicrobial materials., (Copyright © 2020 Elsevier Inc. All rights reserved.)

• The influence and interactions of ILs in LC-HPC solutions were studied. • HRMAS unveiled non-polar IL domain and more hydrophobic HPC surface interactions. • Both hydrophilic and hydrophobic interactions take place between HPC and ILs. • Longer side-chain ILs produce swelling on LC-HPC solutions. The demand for better cellulose solvents has driven the search for new and improved materials to enable the processing of this polysaccharide. Ionic liquids have been debated for a long time as interesting alternatives, but the molecular details on the solubilization mechanism have been a matter of controversy. Herein, for the first time, the structure and dynamics of hydroxypropylcellulose (HPC) liquid crystal solutions were probed in the presence of imidazolium ionic liquids (ILs), conjugating rheological measurements with magnetic resonance spectroscopy. This study provides a characterization of the solutions macroscopic behaviour, where the liquid crystalline (LC) properties were maintained. Using ILs with different side chain lengths, the influence of the hydrophobic IL domain in the solvation abilities of ILs towards a cellulose derived polymer was accessed, providing experimental evidence on these interactions. [ABSTRACT FROM AUTHOR]

The incorporation of magnetic nanoparticles into poly(N-isopropylacrylamide) (PNIPAAm) and chitosan microgels gives rise to hybrid systems that combine the microgels swelling capacity with the interesting features presented in magnetic nanoparticles. The presence of chitosan that act as surfactant for magnetic nanoparticles provides a simplistic approach which allows the encapsulation of magnetic nanoparticles without any previous surface modification. Spherical and highly monodisperse microgels with diameters in the range of 200 to 500 nm were obtained. The encapsulation of magnetic nanoparticles in the polymer matrix was confirmed by high resolution Scanning Electron Microscopy in transmission mode. Volume phase transition of the microgels was accessed by Dynamic Light Scattering measurements. It was observed that the thermosensitivity of the PNIPAM microgels still persists in the hybrid microgels; however, the swelling ability is compromised in the microgels with highest chitosan content. The heating performance of the hybrid magnetic microgels, when submitted to an alternating magnetic field, was also evaluated demonstrating the potential of these systems for hyperthermia treatments. [ABSTRACT FROM AUTHOR]