PDMS biochips with integrated waveguides

Azmayesh-Fard, Seyed M.; Flaim, Eric; McMullin, J.N.

doi:10.1088/0960-1317/20/8/087002

Cited by 20 publications

(15 citation statements)

References 22 publications

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“…Related studies have revealed that the femtosecond laser is a powerful 3D processing tool with the following advantages: high spatial resolution, high accuracy, and high compatibility with other processing techniques. After the pattern shape is determined on the substrate, glass and polydimethylsiloxane (PDMS) are widely used as the main material because they are transparent and have been widely applied in the biochip or microfluidic systems in recent years [ 8 ]. The advantages of glass-based and PDMS based chips are their high transparency, favorable biocompatibility, and chemical stability.…”

Section: Introductionmentioning

confidence: 99%

Surface Wettability and Electrical Resistance Analysis of Droplets on Indium-Tin-Oxide Glass Fabricated Using an Ultraviolet Laser System

Tsai

Hsu

et al. 2021

Micromachines

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Indium tin oxide (ITO) is widely used as a substrate for fabricating chips because of its optical transparency, favorable chemical stability, and high electrical conductivity. However, the wettability of ITO surface is neutral (the contact angle was approximately 90°) or hydrophilic. For reagent transporting and manipulation in biochip application, the surface wettability of ITO-based chips was modified to the hydrophobic or nearly hydrophobic surface to enable their use with droplets. Due to the above demand, this study used a 355-nm ultraviolet laser to fabricate a comb microstructure on ITO glass to modify the surface wettability characteristics. All of the fabrication patterns with various line width and pitch, depth, and surface roughness were employed. Subsequently, the contact angle (CA) of droplets on the ITO glass was analyzed to examine wettability and electrical performance by using the different voltages applied to the electrode. The proposed approach can succeed in the fabrication of a biochip with suitable comb-microstructure by using the optimal operating voltage and time functions for the catch droplets on ITO glass for precision medicine application. The experiment results indicated that the CA of droplets under a volume of 20 μL on flat ITO substrate was approximately 92° ± 2°; furthermore, due to its lowest surface roughness, the pattern line width and pitch of 110 μm exhibited a smaller CA variation and more favorable spherical droplet morphology, with a side and front view CA of 83° ± 1° and 78.5° ± 2.5°, respectively, while a laser scanning speed of 750 mm/s was employed. Other line width and pitch, as well as scanning speed parameters, increased the surface roughness and resulted in the surface becoming hydrophilic. In addition, to prevent droplet morphology collapse, the droplet’s electric operation voltage and driving time did not exceed 5 V and 20 s, respectively. With this method, the surface modification process can be employed to control the droplet’s CA by adjusting the line width and pitch and the laser scanning speed, especially in the neutral or nearly hydrophobic surface for droplet transporting. This enables the production of a microfluidic chip with a surface that is both light transmittance and has favorable electrical conductivity. In addition, the shape of the microfluidic chip can be directly designed and fabricated using a laser direct writing system on ITO glass, obviating the use of a mask and complicated production processes in biosensing and biomanipulation applications.

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Section: Introductionmentioning

confidence: 99%

Surface Wettability and Electrical Resistance Analysis of Droplets on Indium-Tin-Oxide Glass Fabricated Using an Ultraviolet Laser System

Tsai

Hsu

et al. 2021

Micromachines

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“…Development of simple and established fluorescence labeling techniques, along with microfluidic systems which enable delivery of extremely low volume samples, have made these sensors even more attractive 26 . Successful development of several silicon and PDMS based optical waveguides 27–30 with integrated microfluidic channels has led to the emergence of a new set of optofluidic sensor devices where femtoliter excitation volumes have brought the detection limits down to single nucleic acids 31 . However, these systems lack any sample preparation capabilities and require fully preprocessed samples for analysis.…”

Section: Introductionmentioning

confidence: 99%

Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection

et al. 2018

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Detection of molecular biomarkers with high specificity and sensitivity from biological samples requires both sophisticated sample preparation and subsequent analysis. These tasks are often carried out on separate platforms which increases required sample volumes and the risk of errors, sample loss, and contamination. Here, we present an optofluidic platform which combines an optical detection section with single nucleic acid strand sensitivity, and a sample processing unit capable of on-chip, specific extraction and labeling of nucleic acid and protein targets in complex biological matrices. First, on-chip labeling and detection of individual lambda DNA molecule down to concentrations of 8fM is demonstrated. Subsequently, we demonstrate the simultaneous capture, fluorescence tagging and detection of both Zika specific nucleic acid and NS-1 protein targets in both buffer and human serum. We show that the dual DNA and protein assay allows for successful differentiation and diagnosis of Zika against cross-reacting species like dengue.

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“…A mold is produced by soft lithography [ 12 , 13 ] or laser fabrication [ 14 – 16 ] in a photoresist layer (SU-8) or a metallic sheet. Hot embossing technique [ 14 , 16 , 17 ] or poured molding method [ 15 , 18 – 20 ] is used to duplicate the mold in a polymer sheet. The peeled polymer replica is sealed to a flat surface to enclose the channels.…”

Section: Techniques For Microfabrication Of Opto-microfluidic Sensorsmentioning

confidence: 99%

“…The peeled polymer replica is sealed to a flat surface to enclose the channels. Much complex structures in a microfluidic device can be developed by stacking multiple polymer layers (100 μm in thickness per layer), similar to a sandwich structure [ 18 , 21 ]. The time period is less than two days starting from design to the realization of a functional device.…”

Section: Techniques For Microfabrication Of Opto-microfluidic Sensorsmentioning

confidence: 99%

Microfabrication and Applications of Opto-Microfluidic Sensors

Zhang

Men

Chen

2011

Sensors

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A review of research activities on opto-microfluidic sensors carried out by the research groups in Canada is presented. After a brief introduction of this exciting research field, detailed discussion is focused on different techniques for the fabrication of opto-microfluidic sensors, and various applications of these devices for bioanalysis, chemical detection, and optical measurement. Our current research on femtosecond laser microfabrication of optofluidic devices is introduced and some experimental results are elaborated. The research on opto-microfluidics provides highly sensitive opto-microfluidic sensors for practical applications with significant advantages of portability, efficiency, sensitivity, versatility, and low cost.

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PDMS biochips with integrated waveguides

Cited by 20 publications

References 22 publications

Surface Wettability and Electrical Resistance Analysis of Droplets on Indium-Tin-Oxide Glass Fabricated Using an Ultraviolet Laser System

Surface Wettability and Electrical Resistance Analysis of Droplets on Indium-Tin-Oxide Glass Fabricated Using an Ultraviolet Laser System

Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection

Microfabrication and Applications of Opto-Microfluidic Sensors

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