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A major obstacle in the development of highly sensitive electrochemical biosensors is the issue of electrode fouling due to non-specific adsorption of biomolecules on the electrode/sensor surface. The efficacy of such systems is also limited by the need for high densities of immobilized bioactive molecules on the sensor surface. Biomolecules have a natural tendency to randomly adsorb on solid surfaces, which greatly reduces the bioefficiency and biofunctionality of sensing devices. Polymer brushes have recently attracted considerable interest for generating molecularly defined surfaces for applications in nanotechnology, molecular biology, and biomedical sciences. Two main advantages of using polymer brush systems are the ability to mitigate non-specific adsorption and the creation of tailor-made surfaces to control the immobilization of bioanalytes through specific receptor recognition interactions. The use of polymer brushes allows the formation of uniform surfaces with controlled chemical architecture that exhibits good chemical and thermal stability. In this highlight, we use recent examples to demonstrate the role of polymer brushes in the development of sensitive electrochemical biosensors with low detection limits.

An environmentally friendly development process using supercritical carbon dioxide (scCO2) was applied to a novel molecular glass resist made from a molecular waterwheel (‘Noria’), and patterned by electron-beam (EB) lithography. The physical and lithographic properties of a Noria derivative, tert-butoxycarbonyl-protected Noria (‘Noria-BOC’), were examined to evaluate it as a next-generation resist in terms of its solubility, film-forming ability, thermal stability, photosensitivity, and patterning properties. FT-IR spectra and contrast curve studies revealed the good photo-induced deprotection reactivity of Noria-BOC and the excellent negative-tone characteristics of scCO2 development, respectively. The EB-patterning of Noria-BOC followed by development in scCO2 gave clear lithographic patterns with sub-100 nm resolution.