High-resolution fabrication of nanopatterns by multistep iterative miniaturization of hot-embossed prestressed polymer films and constrained shrinking

Sayed, Shady; Selvaganapathy, P. Ravi

doi:10.1038/s41378-021-00338-y

Cited by 10 publications

(7 citation statements)

References 30 publications

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“…One limitation is that our topographical array shows a higher heterogeneity in terms of the roughness levels generated and is restricted to the microscale level due to the inherent capabilities of our methods. Thus, emerging methods such as thermal shrinking may produce more micro-scale reproducibility ( Sayed and Selvaganapathy, 2022 ).…”

Section: Discussionmentioning

confidence: 99%

Surface roughness modulates EGFR signaling and stemness of triple-negative breast cancer cells

Rosado-Galindo

Domenech²

2023

Front. Cell Dev. Biol.

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Introduction: Cancer stem cells (CSC), a major culprit of drug-resistant phenotypes and tumor relapse, represent less than 2 % of the bulk of TNBC cells, making them difficult to isolate, study, and thus, limiting our understanding of the pathogenesis of the disease. Current methods for CSC enrichment, such as 3D spheroid culture, genetic modification, and stem cell conditioning, are time consuming, expensive, and unsuitable for high-throughput assays. One way to address these limitations is to use topographical stimuli to enhance CSC populations in planar culture. Physical cues in the breast tumor microenvironment can influence cell behavior through changes in the mechanical properties of the extracellular matrix (ECM). In this study, we used topographical cues on polystyrene films to investigate their effect on the proteome and stemness of standard TNBC cell lines.Methods: The topographical polystyrene-based array was generated using razor printing and polishing methods. Proteome data were analyzed and enriched bioprocesses were identified using R software. Stemness was assessed measuring CD44, CD24 and ALDH markers using flow cytometry, immunofluorescence, detection assays, and further validated with mammosphere assay. EGF/EGFR expression and activity was evaluated using enzyme-linked immunosorbent assay (ELISA), immunofluorescence and antibody membrane array. A dose-response assay was performed to further investigate the effect of surface topography on the sensitivity of cells to the EGFR inhibitor.Results: Surface roughness enriched the CSC population and modulated epidermal growth factor receptor (EGFR) signaling activity in TNBC cells. Enhanced proliferation of MDA-MB-468 cells in roughness correlated with upregulation of the epidermal growth factor (EGF) ligand, which in turn corresponded with a 3-fold increase in the expression of EGFR and a 42% increase in its phosphorylation compared to standard smooth culture surfaces. The results also demonstrated that phenotypic changes associated with topographical (roughness) stimuli significantly decreased the drug sensitivity to the EGFR inhibitor gefitinib. In addition, the proportion of CD44+/CD24−/ALDH+ was enhanced on surface roughness in both MDA-MB-231 and MDA-MB-468 cell lines. We also demonstrated that YAP/TAZ activation decreased in a roughness-dependent manner, confirming the mechanosensing effect of the topographies on the oncogenic activity of the cells.Discussion: Overall, this study demonstrates the potential of surface roughness as a culture strategy to influence oncogenic activity in TNBC cells and enrich CSC populations in planar cultures. Such a culture strategy may benefit high-throughput screening studies seeking to identify compounds with broader tumor efficacy.

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Section: Discussionmentioning

confidence: 99%

Surface roughness modulates EGFR signaling and stemness of triple-negative breast cancer cells

Rosado-Galindo

Domenech²

2023

Front. Cell Dev. Biol.

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“…3. Various fabrication methods for PDMS have been reported in the last decade [33][34][35] , but few have realized patterning and release of suspended PDMS thin films. Considering the difficulty of simultaneous compatible fabrication of PDMS-suspended beams and silicon zigzag beams, the two subsystems patterning process is intentionally designed on the top and bottom sides, respectively.…”

Section: Fabricationmentioning

confidence: 99%

Multimodal MEMS vibration energy harvester with cascaded flexible and silicon beams for ultralow frequency response

Feng

et al. 2023

Microsyst Nanoeng

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Scavenged energy from ambient vibrations has become a promising energy supply for autonomous microsystems. However, restricted by device size, most MEMS vibration energy harvesters have much higher resonant frequencies than environmental vibrations, which reduces scavenged power and limits practical applicability. Herein, we propose a MEMS multimodal vibration energy harvester with specifically cascaded flexible PDMS and “zigzag” silicon beams to simultaneously lower the resonant frequency to the ultralow-frequency level and broaden the bandwidth. A two-stage architecture is designed, in which the primary subsystem consists of suspended PDMS beams characterized by a low Young’s modulus, and the secondary system consists of zigzag silicon beams. We also propose a PDMS lift-off process to fabricate the suspended flexible beams and the compatible microfabrication method shows high yield and good repeatability. The fabricated MEMS energy harvester can operate at ultralow resonant frequencies of 3 and 23 Hz, with an NPD index of 1.73 μW/cm3/g2 @ 3 Hz. The factors underlying output power degradation in the low-frequency range and potential enhancement strategies are discussed. This work offers new insights into achieving MEMS-scale energy harvesting with ultralow frequency response.

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“…3. There have been various fabrication methods of PDMS reported in the decade [33][34][35] , but few realized patterning and releasing suspended PDMS thin lms. Especially considering the di culty of simultaneous compatible fabrication of PDMS suspended beams and silicon zigzag beams, the patterning process of the two subsystems is designed intentionally on the top and bottom sides respectively.…”

Section: Fabricationmentioning

confidence: 99%

Multimodal MEMS vibration energy harvester with cascaded flexible and silicon beams for ultra-low frequency response

Wang

Feng

et al. 2022

Preprint

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Scavenging energy from ambient vibrations has become a promising energy supply for autonomous microsystems. However, restricted by device size, most MEMS vibration energy harvesters have much higher resonant frequencies than environmental vibrations, which reduces scavenged power and limits applicable scenarios. Herein, we propose a MEMS multimodal vibration energy harvester with specifically cascaded flexible PDMS and zigzag silicon beams to lower the resonant frequency to Hertz level and to broaden the bandwidth simultaneously. A two-stage architecture is designed, in which the primary subsystem consists of suspended PDMS beams characterized by low Young’s modulus, and the secondary system consists of zigzag silicon beams. We also propose the PDMS lift-off process to fabricate the suspended flexible beams, a compatible microfabrication method with high yield and good repeatability. The fabricated MEMS energy harvester can operate at ultra-low resonant frequencies of 3 Hz and 23 Hz, achieving maximum normalized voltage density of 200 V/cm3/g2 @ 3 Hz. The reasons for output power degradation in the low frequency range and the potential enhancement strategies are discussed. This work offers new insights for achieving MEMS scale energy harvesting with ultra-low frequency response.

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High-resolution fabrication of nanopatterns by multistep iterative miniaturization of hot-embossed prestressed polymer films and constrained shrinking

Cited by 10 publications

References 30 publications

Surface roughness modulates EGFR signaling and stemness of triple-negative breast cancer cells

Surface roughness modulates EGFR signaling and stemness of triple-negative breast cancer cells

Multimodal MEMS vibration energy harvester with cascaded flexible and silicon beams for ultralow frequency response

Multimodal MEMS vibration energy harvester with cascaded flexible and silicon beams for ultra-low frequency response

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