Mechanochemical Lithography

Abstract

Surfaces with patterned biomolecules have wide applications in biochips and biomedical diagnostics. However, most patterning methods are inapplicable to physiological conditions and incapable of creating complex structures. Here, we develop a mechanochemical lithography (MCL) method based on compressive force-triggered reactions. In this method, biomolecules containing a bioaffinity ligand and a mechanoactive group are used as mechanochemical inks (MCIs). The bioaffinity ligand facilitates concentrating MCIs from surrounding solutions to a molded surface, enabling direct and continuous printing in an aqueous environment. The mechanoactive group facilitates covalent immobilization of MCIs through force-triggered reactions, thus avoiding the broadening of printed features due to the diffusion of inks. We discovered that the ubiquitously presented amino groups in biomolecules can react with maleimide through a forcetriggered Michael addition. The resulting covalent linkage is mechanically and chemically stable. As a proof-of-concept, we fabricate patterned surfaces of biotin and His-tagged proteins at nanoscale spatial resolution by MCL and verify the resulting patterns by fluorescence imaging. We further demonstrated the creation of multiplex protein patterns using this technique.

Polymer mechanochemistry: from single molecule to bulk material

“…Recently, Prof. Cao and co-workers also developed a mechanochemical lithography (MCL) method based on compressive force-triggered reactions to prepare a special surface with patterned biomolecules. 50 In their systems, the mechanochemical inks (MCIs) consist of biomolecules containing both a bio-affinity ligand and a mechanoactive group. The presence of the mechanoactive group facilitates covalent immobilization of MCIs through compressive force-triggered reactions in an aqueous solution mixture, allowing for direct and continuous printing.…”

Mechanically Gated Formation of Donor–Acceptor Stenhouse Adducts Enabling Mechanochemical Multicolor Soft Lithography

“…6 Finally, we contrast the STAMMP process with a recent report by Mei et al that leverages force-accelerated amine conjugation to functionalize silicon surfaces following the more conventional lithographic approach. 36…”

Coumarin Dimer Is an Effective Photomechanochemical AND Gate for Small-Molecule Release

“…This has to be balanced against the reduced stability of PPGs activatable with wavelengths >500 nm under ambient light or the technical complexity of two-photon activation. Finally, photomechanochemical gating allows actions that are currently either impossible, such as temporospatial control over initiating cross-linking within specific subvolumes of a polymeric material experiencing load above a predefined threshold, or that are impractically complex, such as mechanochemical soft lithography. , …”

“…Finally, photomechanochemical gating allows actions that are currently either impossible, such as temporospatial control over initiating cross-linking within specific subvolumes of a polymeric material experiencing load above a predefined threshold, 23 or that are impractically complex, such as mechanochemical soft lithography. 24,25 Longer-term exploitation of the potential of photomechanochemical reaction gating requires the design and characterization of photochemically inert moieties whose reactions are accelerated by a stretching force and yield a chromophore capable of initiating further thermally activated reactions upon light irradiation (Figure 1c). The contemporary interest in both optically and mechanically controlled delivery of smallmolecule payloads makes the design and characterization of organic mechanochromic reactions that yield PPGs a particularly advantageous starting point.…”