Solution-Cast High-Aspect-Ratio Polymer Structures from Direct-Write Templates

Rajput, Deepak; Costa, Lino; Lansford, Kathleen; Terekhov, Alexander; Hofmeister, William

doi:10.1021/am302009e

Cited by 28 publications

(22 citation statements)

References 23 publications

(36 reference statements)

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“…It offers freedom from expensive photomasks but requires increased patterning time and typically patterns with lower resolution. This technique has been used to successfully prepare molds for casting high‐aspect‐ratio polymeric structures . A variant is two‐photon patterning (sometimes referred to as direct‐write or multiphoton lithography), which irradiates the photoresist with a focused infrared laser .…”

Section: Fabrication Techniquesmentioning

confidence: 99%

“…This technique has been used to successfully prepare molds for casting high-aspectratio polymeric structures. [170] A variant is two-photon patterning (sometimes referred to as direct-write or multiphoton lithography), which irradiates the photoresist with a focused infrared laser. [177] The high photon density in the focal point results in upconverted photons with UV energies, resulting in a smaller patterning region and enhanced resolution.…”

Section: Photolithographymentioning

confidence: 99%

“…[132] Copyright 2019, Elsevier. Advantages Disadvantages Direct (write) laser lithography Nanoneedles [170] 1-50 [171] ≤100 [171] Flexible design (no fixed tooling required) Typically easier to pattern large areas (e.g., whole wafers) compared to multiphoton approaches Compromise on resolution due to larger laser beam spot size Requires relatively specialist equipment a)…”

Section: Nanosphere and Colloidal Lithographymentioning

confidence: 99%

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High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

et al. 2020

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Materials patterned with high‐aspect‐ratio nanostructures have features on similar length scales to cellular components. These surfaces are an extreme topography on the cellular level and have become useful tools for perturbing and sensing the cellular environment. Motivation comes from the ability of high‐aspect‐ratio nanostructures to deliver cargoes into cells and tissues, access the intracellular environment, and control cell behavior. These structures directly perturb cells' ability to sense and respond to external forces, influencing cell fate, and enabling new mechanistic studies. Through careful design of their nanoscale structure, these systems act as biological metamaterials, eliciting unusual biological responses. While predominantly used to interface eukaryotic cells, there is growing interest in nonanimal and prokaryotic cell interfacing. Both experimental and theoretical studies have attempted to develop a mechanistic understanding for the observed behaviors, predominantly focusing on the cell–nanostructure interface. This review considers how high‐aspect‐ratio nanostructured surfaces are used to both stimulate and sense biological systems.

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Section: Fabrication Techniquesmentioning

confidence: 99%

Section: Photolithographymentioning

confidence: 99%

Section: Nanosphere and Colloidal Lithographymentioning

confidence: 99%

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High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

et al. 2020

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“…In the present work, femtosecond laser machining was carried out using the system described by Rajput. 38 A dry microscope objective, namely a Nikon CF Plan Achromat 79173, was used to focus the femtosecond laser beam on the surface of the fused silica wafer. Energy per pulse of 3.2 μJ was used to open each pore.…”

Section: Methodsmentioning

confidence: 99%

Ultrathin Polymer Membranes with Patterned, Micrometric Pores for Organs-on-Chips

Costa

Terekhov

Gnecco³

et al. 2016

ACS Appl. Mater. Interfaces

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The basal lamina or basement membrane (BM) is a key physiological system that participates in physicochemical signaling between tissue types. Its formation and function are essential in tissue maintenance, growth, angiogenesis, disease progression, and immunology. In vitro models of the BM, e.g., Boyden and transwell chambers, are common in cell biology and lab-on-a-chip devices where cells require apical and basolateral polarization. Extravasation, intravasation, membrane transport of chemokines, cytokines, chemotaxis of cells, and other key functions are routinely studied in these models. The goal of the present study was to integrate a semipermeable ultrathin polymer membrane with precisely positioned pores of 2 μm diameter in a microfluidic device with apical and basolateral chambers. We selected poly (L-lactic acid) (PLLA), a transparent biocompatible polymer, to prepare the semipermeable ultrathin membranes. The pores were generated by pattern transfer using a three-step method coupling femtosecond laser machining, polymer replication, and spin coating. Each step of the fabrication process was characterized by scanning electron microscopy to investigate reliability of the process and fidelity of pattern transfer. In order to evaluate the compatibility of the fabrication method with organs-on-a-chip technology, porous PLLA membranes were embedded in polydimethylsiloxane (PDMS) microfluidic devices and used to grow human umbilical vein endothelial cells (HUVECS) on top of the membrane with perfusion through the basolateral chamber. Viability of cells, optical transparency of membranes and strong adhesion of PLLA to PDMS were observed, thus confirming the suitability of the prepared membranes for use in organs-on-a-chip devices.

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“…The use of laser equipment to cut and engrave materials is well established and used extensively throughout a wide range of industries. [4][5][6][7][8][9][10][11][12] The resolution of the resulting pattern is dependent on the quality of the laser engraver and is adjustable by following the parameters from the calibration. The particular "delicate" substrate used in the current manuscript is a porous breathable membrane based on polytetrafluoroethylene (PTFE) which was successfully used in previous studies to implement a three phase interface concept to breathe gases in as well as out of the electrochemical cells.…”

Section: Introductionmentioning

confidence: 99%

Patterning of conducting layers on breathable substrates using laser engraving for gas sensors

Kolodziejczyk

Winther‐Jensen

Pereira

et al. 2015

J of Applied Polymer Sci

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Most of the techniques used for micro and nano‐patterning currently are of high quality and reproducibility, but they require expensive equipment and involve many time‐consuming steps to achieve the desired results. We herein report a patterning method of conducting layers on breathable substrates using a fast, simple, and mask‐less laser engraving technique. A resolution in the range of 30 μm has been successfully achieved in this report. The method is fast and the pattern can be easily changed or redesigned within a few minutes. The patterning time for a 25 cm2 sample is approximately 3 minutes. In comparison, patterning a sample of the same size using photolithography requires up to 4 hours. In this manuscript, we describe the laser patterning process, how to improve the patterning resolution, the calibration steps involved as well as an application for organic electrochemical transistors as gas sensors for detecting oxygen or sulphur dioxide. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42359.

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Solution-Cast High-Aspect-Ratio Polymer Structures from Direct-Write Templates

Cited by 28 publications

References 23 publications

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

Ultrathin Polymer Membranes with Patterned, Micrometric Pores for Organs-on-Chips

Patterning of conducting layers on breathable substrates using laser engraving for gas sensors

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