For biological imaging using electron microscopy (EM), the use of room‐temperature ionic liquids (RTILs) has been proposed as an alternative to traditional lengthy preparation methods. With their low vapor pressures and conductivity, RTILs can be applied onto hard‐to‐image soft and/or wet samples without dehydration – allowing for a more representative, hydrated state of material and opening the possibility for visualization of in situ physiological processes using conventional EM systems. However, RTILs have yet to be utilized to their full potential by microscopists and microbiologists alike. To this end, this review aims to provide a comprehensive summary of biological applications of RTILs for EM to bridge the RTIL, in situ microscopy, and biological communities. We outline future research avenues for the use of RTILs for the EM observation of biological samples, notably i) RTIL selection and optimization, ii) applications for live cell processes and iii) electron beam and ionic liquid interaction studies.

Surface modifications can be applied to biomaterials to alter the various surface properties that influence protein‐material interactions and the cellular response. The plasma protein fetuin‐A has been found to adsorb to many biomaterials but details of its interactions with polydimethylsiloxane (PDMS) and roles in regulating the immune response are not clear. Here, PDMS modifications are achieved by altering the ratio of PDMS formulations to control elastic modulus, and by coating PDMS with polydopamine (PDA) to attach fetuin‐A. Surface characterization confirmed that altering the PDMS formulation changed the elastic modulus without affecting surface wetting properties. Surface roughness was measured using atomic force microscopy and surface chemistry was determined using X‐ray photoelectron spectroscopy, with only minor changes detected on the softest samples. PDA deposition on PDMS was confirmed and contact angle measurements demonstrated an increase in hydrophilicity. Fetuin‐A adsorption was influenced by the PDMS formulations, adsorption changed in a competitive plasma environment, and PDA was able to immobilize the greatest amount of fetuin‐A. The inflammatory effects of fetuin‐A were investigated, and data suggests that the elastic modulus influences cytokine secretion from macrophages at certain timepoints, a result likely due to varied protein amounts and orientations/conformations in response to material stiffness. The addition of a PDA layer demonstrated the potentially cytokine mitigating effect upon fetuin‐A immobilization when compared to unmodified PDMS samples. The results provide new insight into the interactions of fetuin‐A with PDMS and PDA, and the potential immune regulatory properties of fetuin‐A modified materials.