| 1. |
- Decrop, Deborah, et al.
(författare)
-
Single-step imprinting of femtoliter microwell arrays allows digital bioassays with attomolar limit of detection
- 2017
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 9:12, s. 10418-10426
-
Tidskriftsartikel (refereegranskat)abstract
- Bead-based microwell array technology is growing as an ultrasensitive target detection tool. However, dissemination of the technology and its commercial use are hampered by current fabrication methods for hydrophilic-in-hydrophobic microwell arrays, which are either expensive or labour-intensive to manufacture, or which results in low bead seeding efficiencies. In this paper, we present a novel single-step manufacturing method for imprinting cheap and disposable hydrophilic-in-hydrophobic microwell arrays suitable for single-molecule detection. Single-step imprinting of hydrophilic-in-hydrophobic microwell arrays is made possible using an innovative surface energy replication approach by means of a hydrophobic thiol-ene polymer formulation. In this polymer, hydrophobic-moiety-containing monomers self-assemble against the hydrophobic surface of the imprinting stamp, which results in a hydrophobic replica surface after polymerization. After removing the stamp, hydrophilic wells are obtained with the well bottoms consisting of glass substrate. We demonstrate that the hydrophilic-in-hydrophobic imprinted microwell arrays enable successful and efficient self-assembly of individual water droplets and seeding of magnetic beads with loading efficiencies up to 96%. We also demonstrate the suitability of the microwell arrays for the isolation and detection of single-molecules achieving a limit of detection of 17.4 aM when performing a streptavidin-biotin binding assay. The ease of manufacturing demonstrated here is expected to allow translation of digital microwell array technology towards diagnostic applications.
|
|
| 2. |
- Decrop, Deborah, et al.
(författare)
-
Single-step manufacturing of femtoliter microwell arrays in a novel surface energy mimicking polymer
- 2015
-
Ingår i: 18th International Conference on Solid-State Sensors, Actuators and Microsystems (IEEE TRANSDUCER 2015). - : IEEE.
-
Konferensbidrag (refereegranskat)abstract
- We report a novel polymer material formulation and stamp-molding technique that enable rapid single-step manufacturing of hydrophilic-in-hydrophobic microwell arrays. We developed a modified thiol-ene-epoxy polymer (mOSTE+) formulation that mimics the surface energy of its mold during polymerization. The polymer inherits the surface energy from the mold through molecular self-assembly, in which functional monomers self-assemble at the interface between the liquid prepolymer and the mold surface. Combining this novel mOSTE+ material with a stamp-molding process leads to simultaneous surface energy mimicking and micro-structuring. This method was used to manufacture microwells with hydrophilic bottom and hydrophobic sidewall, depressed in a surrounding hydrophobic surface. The microwell arrays were successfully tested for the self-assembly of 62’000 femtoliter-droplets. Such femtoliter droplet arrays are useful for, e.g., digital ELISA and single cell/molecule analysis applications.
|
|
| 3. |
- Errando-Herranz, Carlos, et al.
(författare)
-
Biocompatibility of OSTE polymers studied by cell growth experiments
- 2013
-
Ingår i: Proceedings of the 17th Int. Conf. on Miniaturized Systems for Chemistry and Life Sciences (microTAS). - Freiburg, Germany.
-
Konferensbidrag (refereegranskat)abstract
- The recently introduced OSTE polymer technology has shown very useful features for microfluidics for lab-on-a-chip applications. However, no data has yet been published on cell viability on OSTE. In this work, we study the biocompatibility of three OSTE formulations by cell growth experiments. Moreover, we investigate the effect of varying thiol excess on cell viability on OSTE surfaces. The results show poor cell viability on one OSTE formulation, and viability comparable with polystyrene on a second formulation with thiol excess below 60%. In the third formulation, we observe cell proliferation. These results are promising for cell-based assays in OSTE microfluidic devices.
|
|
| 4. |
|
|
| 5. |
- Karlsson, J. Mikael, et al.
(författare)
-
Off-Stoichiometry Improves Photostructuring of Thiol-Enes Through Diffusion-Induced Monomer Depletion
- 2016
-
Ingår i: Microsystems and Nanoengineering. - : Nature Publishing Group. - 2055-7434. ; 2
-
Tidskriftsartikel (refereegranskat)abstract
- Thiol-enes are a group of alternating copolymers with highly ordered networks used in a wide range of applications. Here, “click” chemistry photostructuring in off-stoichiometric thiol-enes is shown to induce microscale polymeric compositional gradients due to species diffusion between non-illuminated and illuminated regions, creating two narrow zones with distinct composition on either side of the photomask feature boundary: a densely cross-linked zone in the illuminated region and a zone with an unpolymerized highly off-stoichiometric monomer composition in the non-illuminated region. By the use of confocal Raman microscopy, it is here explained how species diffusion causes such intricate compositional gradients in the polymer, and how off-stoichiometry results in improved image transfer accuracy in thiol-ene photostructuring. Furthermore, increasing the functional group off-stoichiometry and decreasing photomask feature size is shown to amplify the induced gradients, which potentially leads to a new methodology for microstructuring.
|
|
| 6. |
- Kim, Anna A, et al.
(författare)
-
Wafer-Scale Patterning of Protein Templates for Hydrogel Fabrication
- 2021
-
Ingår i: Micromachines. - : MDPI. - 2072-666X. ; 12:11, s. 1386-1386
-
Tidskriftsartikel (refereegranskat)abstract
- Human-induced pluripotent stem cell-derived cardiomyocytes are a potentially unlimited cell source and promising patient-specific in vitro model of cardiac diseases. Yet, these cells are limited by immaturity and population heterogeneity. Current in vitro studies aiming at better understanding of the mechanical and chemical cues in the microenvironment that drive cellular maturation involve deformable materials and precise manipulation of the microenvironment with, for example, micropatterns. Such microenvironment manipulation most often involves microfabrication protocols which are time-consuming, require cleanroom facilities and photolithography expertise. Here, we present a method to increase the scale of the fabrication pipeline, thereby enabling large-batch generation of shelf-stable microenvironment protein templates on glass chips. This decreases fabrication time and allows for more flexibility in the subsequent steps, for example, in tuning the material properties and the selection of extracellular matrix or cell proteins. Further, the fabrication of deformable hydrogels has been optimized for compatibility with these templates, in addition to the templates being able to be used to acquire protein patterns directly on the glass chips. With our approach, we have successfully controlled the shapes of cardiomyocytes seeded on Matrigel-patterned hydrogels.
|
|
| 7. |
- Ladhani, Laila, et al.
(författare)
-
A 3D microfluidic cage collector for airborne particles
- 2015
-
Ingår i: The 19th International Conference on Miniaturised Systems for Chemistry and Life Sciences, MicroTAS. - : Royal Society of Chemistry. - 9780979806483 ; , s. 79-81
-
Konferensbidrag (refereegranskat)abstract
- We designed, manufactured, and integrated the first 3D microfluidic collector for capturing airborne particles directly into liquid; using an integrated electrostatic precipitator (ESP) sampler, designed for breath diagnostic purposes. The novel collector increases the sampler’s air-to-liquid capture efficiency by 35 times, when compared with previous 2D collectors.
|
|
| 8. |
- Ladhani, Laila, et al.
(författare)
-
Sampling and detection of airborne influenza virus towards point-of-care applications
- 2017
-
Ingår i: PLOS ONE. - : Plos One. - 1932-6203.
-
Tidskriftsartikel (refereegranskat)abstract
- Airborne transmission of the influenza virus contributes significantly to the spread of this infectious pathogen, particularly over large distances when carried by aerosol droplets with long survival times. Efficient sampling of virus-loaded aerosol in combination with a low limit of detection of the collected virus could enable rapid and early detection of airborne influenza virus at the point-of-care setting. Here, we demonstrate a successful sampling and detection of airborne influenza virus using a system specifically developed for such applications. Our system consists of a custom-made electrostatic precipitation (ESP)-based bioaerosol sampler that is coupled with downstream quantitative polymerase chain reaction (qPCR) analysis. Aerosolized viruses are sampled directly into a miniaturized collector with liquid volume of 150 μL, which constitutes a simple and direct interface with subsequent biological assays. This approach reduces sample dilution by at least one order of magnitude when compared to other liquid-based aerosol bio-samplers. Performance of our ESP-based sampler was evaluated using influenza virus-loaded sub-micron aerosols generated from both cultured and clinical samples. Despite the miniaturized collection volume, we demonstrate a collection efficiency of at least 10% and sensitive detection of a minimum of 3721 RNA copies. Furthermore, we show that an improved extraction protocol can allow viral recovery of down to 303 RNA copies and a maximum sampler collection efficiency of 47%. A device with such a performance would reduce sampling times dramatically, from a few hours with current sampling methods down to a couple of minutes with our ESP-based bioaerosol sampler.
|
|
| 9. |
|
|
| 10. |
|
|
