Fabrication of micro-nano patterned materials mimicking the topological structure of extracellular matrix for biomedical applications

With the advent of tissue engineering and biomedicine,the creation of extracellular matrix(ECM)biomaterials for in vitro applications has become a prominent and promising strategy.These ECM materials provide physical,biochemical,and mechanical properties that guide cellular behaviors,such as proliferation,differentiation,migration,and apoptosis.Because micro-and nano-patterned materials have a unique surface topology and low energy replication process that directly affect cellular biological behaviors at the interface,the fabrication of micro-nano pattern biomaterials and the regulation of surface physical and chemical properties are of great significance in the fields of cell regulation,tissue engineering,and regenerative medicine.Herein,we provide a comprehensive review of the progress in the fabrication and application of patterned materials based on the coupling of mechanical action at the micro-and nano-meter scale,including photolithography,micro-contact printing,electron beam lithography,electrospinning,and 3D printing technology.Furthermore,a summary of the fabrication process,underlying principles,as well as the advantages and disadvantages of various technologies are reviewed.We also discuss the influence of material properties on the fabrication of micro-and nano-patterns.

Advanced unconventional techniques for sub-100 nm nanopatterning

Patterned nanostructures with ultrasmall features endow functional devices with unique nanoconfinement and performance enhancements.The increasing demand for miniaturization has stimulated the development of sub-100 nm nanopatterning techniques.Beyond conventional lithography—which is limited by unavoidable factors—advanced patterning techniques have been reported to produce nanoscale features down to molecular or even atomic scale.In this review,unconventional techniques for sub-100 nm nanopatterning are discussed,in particular the principles by which to achieve the desired patterns(among other important issues).Such techniques can be classified into three categories:template-replica,template-induced,and template-free techniques.Moreover,multi-dimensional nanostructures consist of various building materials,the unique properties of which are summarized.Finally,the remaining challenges and opportunities for large-scale patterning,the improvement of device perfor-mance,the multi-dimensional nanostructures of biocompatible materials,molecular-scale patterning,and the carbon footprint requirements for future nanofabrication processes are discussed.