Bioinspired Shear-Flow-Driven Layer-by-Layer in Situ Self-Assembly

Abstract

Layer-by-layer (LbL) assembly is widely applied as a coating technique for the nanoscale control of architecture and related properties. However, its translational applications are limited by the time-consuming and laborious nature of the process. Inspired by the blood-clotting process, herein, we develop a shear-flow-driven LbL (SF-LbL) self-assembly approach that accelerates the adsorption rate of macromolecules by mechanically configuring the polymer chain via a coil–stretch transition, which effectively simplifies and speeds the diffusion-controlled assembly process. The structural characteristics and surface homogeneity of the SF-LbL films are improved, and diverse three-dimensional structures can be achieved. Functional SF-LbL-assembled surfaces for corneal modification are successfully fabricated, and the surface of wounded rat corneas and skin can be directly decorated in situ with SF-LbL nanofilms due to the advantages of this approach. Furthermore, in situ SF-LbL self-assembly has promise as a simple approach for the wound dressing for interventional therapeutics in the clinic, as illustrated by the successful in situ fabrication of drug-free layers consisting of chitosan and heparin on the dorsal skin of diabetic mice to rescue defective wound healing. This bioinspired self-assembly approach is expected to provide a robust and versatile platform with which to explore the surface engineering of nanofilms in science, engineering, and medicine.

Bioinspired Flexible Hydrogelation with Programmable Properties for Tactile Sensing

“…In order to clarify the mechanism underlying architectural untwisting‐induced enhancement of the mechanical properties, numerical models of nanofibers and nanoribbons were created and hydrodynamic simulations were performed by mesoscopic dissipative particle dynamics methods (Figure 2b). [ 45 ] The simulation results demonstrated that when applied oscillatory shear, the nanoribbons‐based hydrogel showed a larger real‐part of the complex response function compared to the nanofibers‐based counterpart (Figure 2c), corresponding to a higher G′ as revealed in experiments. Similar results were also observed in the strain–stress curves (Lissajous curves) of the two systems (Figure 2d), where the nanoribbons‐based hydrogel presented more phase difference compared with the nanofibrillar one.…”

Bioinspired Flexible Hydrogelation with Programmable Properties for Tactile Sensing

“…In order to clarify the mechanism underlying architectural untwisting‐induced enhancement of the mechanical properties, numerical models of nanofibers and nanoribbons were created and hydrodynamic simulations were performed by mesoscopic dissipative particle dynamics methods (Figure 2b). [ 45 ] The simulation results demonstrated that when applied oscillatory shear, the nanoribbons‐based hydrogel showed a larger real‐part of the complex response function compared to the nanofibers‐based counterpart (Figure 2c), corresponding to a higher G′ as revealed in experiments. Similar results were also observed in the strain–stress curves (Lissajous curves) of the two systems (Figure 2d), where the nanoribbons‐based hydrogel presented more phase difference compared with the nanofibrillar one.…”

Hydrodynamic-derived centrifugal blood pump design for stable-low-flow-rate rate performance: from surface to structure

“…Under high flow rates and prolonged shear forces, these coatings are unstable. Fluid-driven conditions, however, fully stretch molecular chains, exposing more active sites and enhancing coating adhesion [ [16] , [17] , [18] , [19] , [20] , [21] ].

Fig.

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“…Therefore, designing coatings with enhanced binding strength to the substrate is critical. The manipulation of molecular architecture and related properties under fluid shear forces represents a novel technique [ 29 ]. The shear-flow-driven layer-by-layer self-assembly approach accelerates the adsorption rate of macromolecules by mechanically configuring the polymer chain through a coil-stretch transition, which effectively simplifies and hastens the diffusion-controlled assembly process [ 29 ].…”

Bioinspired Hierarchical Liquid‐Metacrystal Fibers for Chiral Optics and Advanced Textiles

“…As the CNC suspensions exit the nozzle, traction forces exerted by the Ca 2+ ions drive the Na‐Alg motion outward and then form a solid‐like hydrogel layer at the liquid–liquid interfaces, during which Na‐Alg shear‐flow induces the transition of CNC arrangements from an aligned order into a cholesteric order. [ 18 ] As a result, the LMC fibers possess hierarchical core–sheath architectures, in which a Ca‐Alg hydrogel sheath encloses a colloidal cholesteric core with circularly symmetrical structures. The thickness of the hydrogel sheath relative to the diameter of the LMC fibers is a constant value (Figure S2, Supporting Information).…”

Bioinspired Flexible Hydrogelation with Programmable Properties for Tactile Sensing

“…In order to clarify the mechanism underlying architectural untwisting‐induced enhancement of the mechanical properties, numerical models of nanofibers and nanoribbons were created and hydrodynamic simulations were performed by mesoscopic dissipative particle dynamics methods (Figure 2b). [ 45 ] The simulation results demonstrated that when applied oscillatory shear, the nanoribbons‐based hydrogel showed a larger real‐part of the complex response function compared to the nanofibers‐based counterpart (Figure 2c), corresponding to a higher G′ as revealed in experiments. Similar results were also observed in the strain–stress curves (Lissajous curves) of the two systems (Figure 2d), where the nanoribbons‐based hydrogel presented more phase difference compared with the nanofibrillar one.…”

Hydrodynamic-derived centrifugal blood pump design for stable-low-flow-rate rate performance: from surface to structure

“…Under high flow rates and prolonged shear forces, these coatings are unstable. Fluid-driven conditions, however, fully stretch molecular chains, exposing more active sites and enhancing coating adhesion [ [16] , [17] , [18] , [19] , [20] , [21] ].

Fig.

…”

“…Therefore, designing coatings with enhanced binding strength to the substrate is critical. The manipulation of molecular architecture and related properties under fluid shear forces represents a novel technique [ 29 ]. The shear-flow-driven layer-by-layer self-assembly approach accelerates the adsorption rate of macromolecules by mechanically configuring the polymer chain through a coil-stretch transition, which effectively simplifies and hastens the diffusion-controlled assembly process [ 29 ].…”

Bioinspired Hierarchical Liquid‐Metacrystal Fibers for Chiral Optics and Advanced Textiles

“…As the CNC suspensions exit the nozzle, traction forces exerted by the Ca 2+ ions drive the Na‐Alg motion outward and then form a solid‐like hydrogel layer at the liquid–liquid interfaces, during which Na‐Alg shear‐flow induces the transition of CNC arrangements from an aligned order into a cholesteric order. [ 18 ] As a result, the LMC fibers possess hierarchical core–sheath architectures, in which a Ca‐Alg hydrogel sheath encloses a colloidal cholesteric core with circularly symmetrical structures. The thickness of the hydrogel sheath relative to the diameter of the LMC fibers is a constant value (Figure S2, Supporting Information).…”

Bioinspired Flexible Hydrogelation with Programmable Properties for Tactile Sensing

“…In order to clarify the mechanism underlying architectural untwisting‐induced enhancement of the mechanical properties, numerical models of nanofibers and nanoribbons were created and hydrodynamic simulations were performed by mesoscopic dissipative particle dynamics methods (Figure 2b). [ 45 ] The simulation results demonstrated that when applied oscillatory shear, the nanoribbons‐based hydrogel showed a larger real‐part of the complex response function compared to the nanofibers‐based counterpart (Figure 2c), corresponding to a higher G′ as revealed in experiments. Similar results were also observed in the strain–stress curves (Lissajous curves) of the two systems (Figure 2d), where the nanoribbons‐based hydrogel presented more phase difference compared with the nanofibrillar one.…”

Hydrodynamic-derived centrifugal blood pump design for stable-low-flow-rate rate performance: from surface to structure

“…Under high flow rates and prolonged shear forces, these coatings are unstable. Fluid-driven conditions, however, fully stretch molecular chains, exposing more active sites and enhancing coating adhesion [ [16] , [17] , [18] , [19] , [20] , [21] ].

Fig.

…”

“…Therefore, designing coatings with enhanced binding strength to the substrate is critical. The manipulation of molecular architecture and related properties under fluid shear forces represents a novel technique [ 29 ]. The shear-flow-driven layer-by-layer self-assembly approach accelerates the adsorption rate of macromolecules by mechanically configuring the polymer chain through a coil-stretch transition, which effectively simplifies and hastens the diffusion-controlled assembly process [ 29 ].…”

Bioinspired Hierarchical Liquid‐Metacrystal Fibers for Chiral Optics and Advanced Textiles

“…As the CNC suspensions exit the nozzle, traction forces exerted by the Ca 2+ ions drive the Na‐Alg motion outward and then form a solid‐like hydrogel layer at the liquid–liquid interfaces, during which Na‐Alg shear‐flow induces the transition of CNC arrangements from an aligned order into a cholesteric order. [ 18 ] As a result, the LMC fibers possess hierarchical core–sheath architectures, in which a Ca‐Alg hydrogel sheath encloses a colloidal cholesteric core with circularly symmetrical structures. The thickness of the hydrogel sheath relative to the diameter of the LMC fibers is a constant value (Figure S2, Supporting Information).…”