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1.
Biomed Microdevices ; 19(1): 5, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28074385

RESUMO

In this work, we report a simple fabrication method for microelectrodes on a polymethylmethacrylate substrate, using a low-cost laser platform based on a CD-DVD unit for direct rapid-prototyping. We used this laser microfabrication technique to etch any desired design on polymethylmethacrylate substrates to produce microchannels with controlled geometry, with a highly repeatable micron-scale resolution. Those shallow microchannels were then filled with a conductive paste of material of our choice that was converted into microelectrodes of desired shapes and geometries after drying. To validate our process, different geometries, sizes and materials were used as electrodes, and then tested for amperometry and impedance measurements. Development of these microelectrodes is motivated by their potential application in sensors and biosensors, such as glucose and cell counting, as demonstrated in this paper.


Assuntos
Técnicas Biossensoriais/instrumentação , Discos Compactos , Lasers , Microeletrodos , Polimetil Metacrilato/química , Técnicas Biossensoriais/economia , Contagem de Células , Linhagem Celular , Custos e Análise de Custo , Impedância Elétrica , Desenho de Equipamento , Glucose/análise , Microeletrodos/economia , Temperatura , Água
2.
Methods Mol Biol ; 2174: 277-297, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32813257

RESUMO

Stiffness control of cell culture platforms provides researchers in cell biology with the ability to study different experimental models in conditions of mimicking physiological or pathological microenvironments. Nevertheless, the signal transduction pathways and drug sensibility of cancer cells have been poorly characterized widely using biomimetic platforms because the limited experience of cancer cell biology groups about handling substrates with specific mechanical properties. The protein cross-linking and stiffening control are crucial checkpoints that could strongly affect cell adhesion and spreading, misrepresenting the data acquired, and also generating inaccurate cellular models. Here, we introduce a simple method to adhere to polyacrylamide (PAA) hydrogels on glass coverslips without any special treatment for mechanics studies in cancer cell biology. By using a commercial photosensitive glue, Loctite 3525, it is possible to polymerize PAA hydrogels directly on glass surfaces. Furthermore, we describe a cross-linking reaction method to attach proteins to PAA as an alternative method to Sulfo-SANPAH cross-linking, which is sometimes difficult to implement and reproduce. In this chapter, we describe a reliable procedure to fabricate ECM protein-cross-linked PAA hydrogels for mechanotransduction studies on cancer cells.


Assuntos
Resinas Acrílicas/química , Adesivos/química , Adesão Celular , Hidrogéis/química , Neoplasias/patologia , Reagentes de Ligações Cruzadas/química , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Proteínas da Matriz Extracelular/química , Imunofluorescência , Vidro , Células Hep G2 , Humanos , Mecanotransdução Celular , Metacrilatos/química , Neoplasias/química , Microambiente Tumoral
3.
Micromachines (Basel) ; 10(9)2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31480301

RESUMO

Microfluidics has become a very promising technology in recent years, due to its great potential to revolutionize life-science solutions. Generic microfabrication processes have been progressively made available to academic laboratories thanks to cost-effective soft-lithography techniques and enabled important progress in applications like lab-on-chip platforms using rapid- prototyping. However, micron-sized features are required in most designs, especially in biomimetic cell culture platforms, imposing elevated costs of production associated with lithography and limiting the use of such devices. In most cases, however, only a small portion of the structures require high-resolution and cost may be decreased. In this work, we present a replica-molding method separating the fabrication steps of low (macro) and high (micro) resolutions and then merging the two scales in a single chip. The method consists of fabricating the largest possible area in inexpensive macromolds using simple techniques such as plastics micromilling, laser microfabrication, or even by shrinking printed polystyrene sheets. The microfeatures were made on a separated mold or onto existing macromolds using photolithography or 2-photon lithography. By limiting the expensive area to the essential, the time and cost of fabrication can be reduced. Polydimethylsiloxane (PDMS) microfluidic chips were successfully fabricated from the constructed molds and tested to validate our micro-macro method.

4.
Lab Chip ; 19(20): 3512-3525, 2019 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-31544189

RESUMO

The study of mechanotransduction signals and cell response to mechanical properties requires designing culture substrates that possess some, or ideally all, of the following characteristics: (1) biological compatibility and adhesive properties, (2) stiffness control or tunability in a dynamic mode, (3) patternability on the microscale and (4) integrability in microfluidic chips. The most common materials used to address cell mechanotransduction are hydrogels, due to their softness. However, they may be impractical when complex scaffolds are sought and they lack viscous dissipative properties that are very important in mechanobiology. In this work, we show that an off-the-shelf, biocompatible photosensitive glue, Loctite 3525, may be used readily in mechanobiology assays without any special treatment prior to fabrication of cell culture platforms. Despite a high (MPa) stiffness easily tunable by UV exposure time at a fixed dose, 3T3 fibroblasts showed a response to the mechanics of the material similar to that obtained on much softer (kPa) hydrogels. Loctite's viscous dissipation properties indeed seemed to be responsible for such cell mechanical response, as suggested by recent works where more complex two-phase hydrogels were employed. More interestingly, it was possible to stiffen soft Loctite substrates by post-exposing them during cell culture, to observe changes in cell spreading caused by a dynamic stiffness modification. Thanks to Loctite 3525's patternability, micropillars were also fabricated to demonstrate the compatibility with traction force microscopy studies. Finally, the glue was used as an excellent adhesion layer for hydrogels on glass or PDMS, without the need for additional treatment, enabling the easy fabrication of microfluidic chips integrating hydrogels.


Assuntos
Técnicas de Cultura de Células/métodos , Metacrilatos/química , Microfluídica/instrumentação , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Técnicas de Cultura de Células/instrumentação , Linhagem Celular , Módulo de Elasticidade , Adesões Focais/efeitos dos fármacos , Humanos , Hidrogéis/química , Mecanotransdução Celular/fisiologia , Metacrilatos/farmacologia , Camundongos , Raios Ultravioleta
5.
Micromachines (Basel) ; 9(4)2018 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30424120

RESUMO

The development of organ-on-chip and biological scaffolds is currently requiring simpler methods for microstructure biocompatible materials in three dimensions, to fabricate structural and functional elements in biomaterials, or modify the physicochemical properties of desired substrates. Aiming at addressing this need, a low-power CD-DVD-Blu-ray laser pickup head was mounted on a programmable three-axis micro-displacement system in order to modify the surface of polymeric materials in a local fashion. Thanks to a specially-designed method using a strongly absorbing additive coating the materials of interest, it has been possible to establish and precisely control processes useful in microtechnology for biomedical applications. The system was upgraded with Blu-ray laser for additive manufacturing and ablation on a single platform. In this work, we present the application of these fabrication techniques to the development of biomimetic cellular culture platforms thanks to the simple integration of several features typically achieved with traditional, less cost-effective microtechnology methods in one step or through replica-molding. Our straightforward approach indeed enables great control of local laser microablation or polymerization for true on-demand biomimetic micropatterned designs in transparent polymers and hydrogels and is allowing integration of microfluidics, microelectronics, surface microstructuring, and transfer of superficial protein micropatterns on a variety of biocompatible materials.

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