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Shape-memory surfaces for cell mechanobiology

View Article: PubMed Central - PubMed

ABSTRACT

Shape-memory polymers (SMPs) are a new class of smart materials, which have the capability to change from a temporary shape ‘A’ to a memorized permanent shape ‘B’ upon application of an external stimulus. In recent years, SMPs have attracted much attention from basic and fundamental research to industrial and practical applications due to the cheap and efficient alternative to well-known metallic shape-memory alloys. Since the shape-memory effect in SMPs is not related to a specific material property of single polymers, the control of nanoarchitecture of polymer networks is particularly important for the smart functions of SMPs. Such nanoarchitectonic approaches have enabled us to further create shape-memory surfaces (SMSs) with tunable surface topography at nano scale. The present review aims to bring together the exciting design of SMSs and the ever-expanding range of their uses as tools to control cell functions. The goal for these endeavors is to mimic the surrounding mechanical cues of extracellular environments which have been considered as critical parameters in cell fate determination. The untapped potential of SMSs makes them one of the most exciting interfaces of materials science and cell mechanobiology.

No MeSH data available.


Schematic illustration of near-infrared-irradiation-induced remote activation of surface shape-memory to direct cell orientations. Cells were seeded on the temporal patterned surface and cultured at 37 °C for 3 h. The NIR light (0.8 W cm−1) was then irradiated until the surface transition was completed. Histograms show the cell orientation angle against pattern direction in non-illuminated (right) and photo-illuminated regions (left). Modified from figure 7 in [89].
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Figure 9: Schematic illustration of near-infrared-irradiation-induced remote activation of surface shape-memory to direct cell orientations. Cells were seeded on the temporal patterned surface and cultured at 37 °C for 3 h. The NIR light (0.8 W cm−1) was then irradiated until the surface transition was completed. Histograms show the cell orientation angle against pattern direction in non-illuminated (right) and photo-illuminated regions (left). Modified from figure 7 in [89].

Mentions: Although a thermally induced shape-memory effect can be achieved by an increase in temperature, shape-memory activation by remote light irradiation could lead to a variety of potential biomedical or other applications. From this regard, we have recently demonstrated the light-induced shape-memory transitions of nanopatterns using gold nanorods (AuNR)-embedded PCL films [84]. AuNRs have been widely employed in numerous biomedical applications, including hyperthermia therapy and biological sensing, due to their photothermal effects [85, 86]. One of the advantages is that the surface plasmon resonance extinction of AuNRs in the near-IR (NIR) region (650–900 nm) provides opportunities for NIR photoabsorption and scattering, in which region there is very limited absorption for most biological tissues, including hemoglobin and water. There have been several reports on remote-controllable SMPs using AuNRs [87, 88]. We have extended this photothermal effect of AuNRs to the local and remote activation of nanopatterns by spatially limiting the NIR-illuminated region. First, the NIR-induced shape-memory nanopatterns are prepared by chemically crosslinking PCL in the presence of AuNRs. Exposure to NIR light can successfully induce the photothermal heating of embedded AuNRs and consequently, the shape-switching transition to permanent patterns over the melting temperature of PCL. The shape-memory transition is spatially limited to the photo-illuminated region, depending on the concentration of embedded AuNRs, the intensity of the NIR light, or the irradiation time. Cell alignment in the NIR-irradiated region was lost and random cell migration was ensured because it caused the surface transition to a flat surface, while cells on the non-illuminated region were still aligned along the direction of the temporal pattern (figure 9) [89]. This finding is novel in that it is the first study that controls the cell orientation locally and remotely on the SMSs by NIR irradiation. The NIR-responsive shape-memory system offers significant promise for the creation of topographically tunable substrates because of their remote-capability to undergo large elastic deformations and to rapidly return to their initial undeformed state.


Shape-memory surfaces for cell mechanobiology
Schematic illustration of near-infrared-irradiation-induced remote activation of surface shape-memory to direct cell orientations. Cells were seeded on the temporal patterned surface and cultured at 37 °C for 3 h. The NIR light (0.8 W cm−1) was then irradiated until the surface transition was completed. Histograms show the cell orientation angle against pattern direction in non-illuminated (right) and photo-illuminated regions (left). Modified from figure 7 in [89].
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036502&req=5

Figure 9: Schematic illustration of near-infrared-irradiation-induced remote activation of surface shape-memory to direct cell orientations. Cells were seeded on the temporal patterned surface and cultured at 37 °C for 3 h. The NIR light (0.8 W cm−1) was then irradiated until the surface transition was completed. Histograms show the cell orientation angle against pattern direction in non-illuminated (right) and photo-illuminated regions (left). Modified from figure 7 in [89].
Mentions: Although a thermally induced shape-memory effect can be achieved by an increase in temperature, shape-memory activation by remote light irradiation could lead to a variety of potential biomedical or other applications. From this regard, we have recently demonstrated the light-induced shape-memory transitions of nanopatterns using gold nanorods (AuNR)-embedded PCL films [84]. AuNRs have been widely employed in numerous biomedical applications, including hyperthermia therapy and biological sensing, due to their photothermal effects [85, 86]. One of the advantages is that the surface plasmon resonance extinction of AuNRs in the near-IR (NIR) region (650–900 nm) provides opportunities for NIR photoabsorption and scattering, in which region there is very limited absorption for most biological tissues, including hemoglobin and water. There have been several reports on remote-controllable SMPs using AuNRs [87, 88]. We have extended this photothermal effect of AuNRs to the local and remote activation of nanopatterns by spatially limiting the NIR-illuminated region. First, the NIR-induced shape-memory nanopatterns are prepared by chemically crosslinking PCL in the presence of AuNRs. Exposure to NIR light can successfully induce the photothermal heating of embedded AuNRs and consequently, the shape-switching transition to permanent patterns over the melting temperature of PCL. The shape-memory transition is spatially limited to the photo-illuminated region, depending on the concentration of embedded AuNRs, the intensity of the NIR light, or the irradiation time. Cell alignment in the NIR-irradiated region was lost and random cell migration was ensured because it caused the surface transition to a flat surface, while cells on the non-illuminated region were still aligned along the direction of the temporal pattern (figure 9) [89]. This finding is novel in that it is the first study that controls the cell orientation locally and remotely on the SMSs by NIR irradiation. The NIR-responsive shape-memory system offers significant promise for the creation of topographically tunable substrates because of their remote-capability to undergo large elastic deformations and to rapidly return to their initial undeformed state.

View Article: PubMed Central - PubMed

ABSTRACT

Shape-memory polymers (SMPs) are a new class of smart materials, which have the capability to change from a temporary shape ‘A’ to a memorized permanent shape ‘B’ upon application of an external stimulus. In recent years, SMPs have attracted much attention from basic and fundamental research to industrial and practical applications due to the cheap and efficient alternative to well-known metallic shape-memory alloys. Since the shape-memory effect in SMPs is not related to a specific material property of single polymers, the control of nanoarchitecture of polymer networks is particularly important for the smart functions of SMPs. Such nanoarchitectonic approaches have enabled us to further create shape-memory surfaces (SMSs) with tunable surface topography at nano scale. The present review aims to bring together the exciting design of SMSs and the ever-expanding range of their uses as tools to control cell functions. The goal for these endeavors is to mimic the surrounding mechanical cues of extracellular environments which have been considered as critical parameters in cell fate determination. The untapped potential of SMSs makes them one of the most exciting interfaces of materials science and cell mechanobiology.

No MeSH data available.