Fig. 7

Bottom-up fabrication technologies (3D printing, self-assembly, soft lithography including Dip-Pen nanolithography (DPN)). a Schematic of how polymer pen lithography works. Reproduced with permission from [126], copyright AAAS, 2008. b Schematic of working principle of DPN. Reproduced with permission from [127], copyright AAAS, 1999. c Schematic of specific setup of two-photon polymerization (2PP) fabrication during experimental. Reproduced with permission from [128], copyright John Wiley and Sons, 2019. d Schematic illustration of the micro structure print by two-photon polymerization. Reproduced with permission from [129], copyright MDPI, 2021