Recent advances in steroidal supramolecular gels

During the last decade or two the interest towards small molecules capable of self-assembly leading to gelation has increased intensively. The investigation of these supramolecular gels aims not only at understanding the fundamental processes underlying gel formation but also at development of new materials with a myriad of applications. Steroids are widely-spread natural products with a large and rigid steroidal nucleus combined with derivatizable functional groups leading to an adjustable polarity profile, which makes them attractive building blocks when designing novel low molecular weight gelators. Due to their unique properties, steroid-based supramolecular gels may find use in applications ranging from materials science and nanoelectronics to their application as reaction media or as sensing and responsive materials. Moreover, biomaterials based on steroidal gels may find use in biomedicine, drug delivery, regenerative medicine, and tissue engineering. This article summarizes the most recent advances in the field of steroidal supramolecular gels in terms of steroid-derived hydro- and organogels, metallogels, two-component gels, and stimuli-responsive gels. Furthermore, the potential applications of the systems are discussed.