Source: BAM
Surface functionalization via molecular design plays a central role in conferring new functionalities to materials. Polydopamine (PDA) holds great interest as a universal platform for surface modification delivering unique chemical and physical properties to nearly any material irrespective of its chemical composition. However, existing conventional methods of PDA deposition show significant limitations in the precision and control over the structure morphology, therefore, restraining advanced PDA applications. In this work, we offer a solution to this issue by presenting, for the first time, the deposition of fine 2D polydopamine microstructures applying the Multiphoton Lithography technique. We use an organic photoinitiator to promote PDA build-up under NIR fs-pulsed laser beam light. The deposition is feasible under different conditions such as alkaline, neutral, and slightly acidic pH of different buffers, as well as with DI water only. Moreover, the morphology and thickness of the PDA micropatterns can be well controlled by velocity and power of the laser beam, thus, revealing the possibility of creating structures with a topography gradient. Presented approach does not need any photomask or microstamp while offering high control over pattern design, as well as spatial and temporal deposition with resolution down to 0.8 µm. Fabricated PDA microstructures can be easily post-functionalized and applied as a primer for covalent immobilization of protein enzymes for further protein detection. The here presented route of PDA patterning may open up new fields of applications where extreme precision of PDA deposition and morphology control are required. Possible applications include multicomponent functional elements, microfluidics, or lab-on-a-chip systems.
High-Precision Micropatterning of Polydopamine by Multiphoton Lithography
Ievgeniia Topolniak, Anna Maria Elert, Xenia Knigge, Goksu Cinar Ciftci, Jörg Radnik, Heinz Sturm
published online in Advanced Materials, article no. 2109509
BAM division Surface Analysis and Interfacial Chemistry and division Physical and Chemical Analysis of Polymers