Single-step design of hydrogel-based microfluidic assays for rapid diagnostics (original) (raw)
Related papers
Biomedicines
Microfluidics is emerging as a promising tool to control physicochemical properties of nanoparticles and to accelerate clinical translation. Indeed, microfluidic-based techniques offer more advantages in nanomedicine over batch processes, allowing fine-tuning of process parameters. In particular, the use of microfluidics to produce nanoparticles has paved the way for the development of nano-scaled structures for improved detection and treatment of several diseases. Here, ionotropic gelation is implemented in a custom-designed microfluidic chip to produce different nanoarchitectures based on chitosan-hyaluronic acid polymers. The selected biomaterials provide biocompatibility, biodegradability and non-toxic properties to the formulation, making it promising for nanomedicine applications. Furthermore, results show that morphological structures can be tuned through microfluidics by controlling the flow rates. Aside from the nanostructures, the ability to encapsulate gadolinium contrast...
Capturing Complex Protein Gradients on Biomimetic Hydrogels for Cell-Based Assays
Advanced Functional Materials, 2009
ABSTRACT A versatile strategy to rapidly immobilize complex gradients of virtually any desired protein on soft poly(ethylene glycol) (PEG) hydrogel surfaces that are reminiscent of natural extracellular matrices (ECM) is reported. A microfluidic chip is used to generate steady-state gradients of biotinylated or Fc-tagged fusion proteins that are captured and bound to the surface in less than 5 min by NeutrAvidin or ProteinA, displayed on the surface. The selectivity and orthogonality of the binding schemes enables the formation of parallel and orthogonal overlapping gradients of multiple proteins, which is not possible on conventional cell culture substrates. After patterning, the hydrogels are released from the microfluidic chip and used for cell culture. This novel platform is validated by conducting single-cell migration experiments using time-lapse microscopy. The orientation of cell migration, as well as the migration rate of primary human fibroblasts, depends on the concentration of an immobilized fibronectin fragment. This technique can be readily applied to other proteins to address a wealth of biological questions with different cell types.
HYDROGEL DISCS ON DIGITAL MICROFLUIDIC DEVICES FOR PROTEOMIC APPLICATIONS
ABSTRACT We introduce the use of immobilized enzymes in hydrogels for proteomic sample processing in digital microfluidic systems. In this technique, pre-formed cylindrical agarose discs bearing immobilized enzymes were integrated into digital microfluidic devices bearing arrays of electrodes.
Microfluidics and hydrogel: A powerful combination
Reactive and Functional Polymers, 2019
Microfluidics is a very useful and promising technology that allowed engineering a huge variety of developments in several fields, such as biology, biomedical engineering, biotechnology, biochemistry, medicine and tissue engineering, among others. Moreover, when microfluidic is combined with hydrogel, the possibilities seem to be limitless. However, it is not found in the bibliography any report that shows the wide range of developments and application fields of this combination. In this review, the bibliography is explored by looking for these new systems that, combining microfluidics and hydrogels, substantially contribute to the state of the art. Seven large application fields are identified-from 649 papers reviewed: 1) cell culture (out of the scope of this review), 2) biosensors, 3) gradient generator microdevices (GGMD), 4) active elements of hydrogel embedded into microfluidic devices, 5) separation devices, 6) models and 7) other uses. Most of these fields are presented and discussed in detail, the great benefits of the combination are highlighted and perspectives on future directions are exposed.
Polymeric microparticles represent a robustly platform for the detection of clinically relevant analytes in biological samples; they can be functionalized encapsulating a multiple types of biologics entities, enhancing their applications as a new class of colloid materials. Microfluidic offers a versatile platform for the synthesis of monodisperse and engineered microparticles. In this work, we report microfluidic synthesis of novel polymeric microparticles endowed with specific peptide due to its superior specificity for target binding in complex media. A peptide sequence was efficiently encapsulated into the polymeric network and protein binding occurred with high affinity (K D 0.1–0.4 M). Fluidic dynamics simulation was performed to optimize the production conditions for monodisperse and stable functionalized micro-gels. The results demonstrate the easy and fast realization, in a single step, of functionalized monodisperse microgels using droplet-microfluidic technique, and how the inclusion of the peptide within polymeric network improve both the affinity and the specificity of protein capture.
Molecules
Poly(ethylene glycol) diacrylate (PEGDA) microgels with tuneable size and porosity find applications as extracellular matrix mimics for tissue-engineering scaffolds, biosensors, and drug carriers. Monodispersed PEGDA microgels were produced by modular droplet microfluidics using the dispersed phase with 49–99 wt% PEGDA, 1 wt% Darocur 2959, and 0–50 wt% water, while the continuous phase was 3.5 wt% silicone-based surfactant dissolved in silicone oil. Pure PEGDA droplets were fully cured within 60 s at the UV light intensity of 75 mW/cm2. The droplets with higher water content required more time for curing. Due to oxygen inhibition, the polymerisation started in the droplet centre and advanced towards the edge, leading to a temporary solid core/liquid shell morphology, confirmed by tracking the Brownian motion of fluorescent latex nanoparticles within a droplet. A volumetric shrinkage during polymerisation was 1–4% for pure PEGDA droplets and 20–32% for the droplets containing 10–40 w...
Soft Matter, 2013
The design of hydrogel matrices for cell encapsulation and tissue regeneration has become increasingly complex. Oftentimes, researchers seek to recapitulate specific biophysical and biochemical cues critical for the resident cell population and an in depth understanding of changes in the local microstructure and rheological properties of the synthetic matrix during enzymatic degradation would be extremely beneficial. Multiple particle tracking microrheology (MPT) enables simultaneous characterization of rheological properties and visualization of the microstructure in an evolving hydrogel scaffold. MPT measures the Brownian motion of fluorescently labeled probe particles embedded in the material, which is directly related to rheological properties using the Generalized Stokes-Einstein Relation (GSER). Here, we study a hydrogel scaffold consisting of a four-arm poly(ethylene glycol) (PEG) end functionalized with norbornene that is cross-linked with both a nondegradable PEG-dithiol and a matrix metalloproteinase (MMP) degradable peptide sequence (KCGPQGYIWGQCK) using thiol-ene chemistry. The material degradation is measured as a function of time and extent of degradability, focusing on measuring the gel-sol transition. Using time-cure superposition, we determine the critical degradation time and critical extent of degradability for this specific gel formulation as t c ¼ 1.85 h and p c ¼ 0.589, respectively, and the critical relaxation exponent, n ¼ 0.16. Finally, spatial information gained by MPT measurements quantifies the heterogeneity within the scaffold showing that these hydrogels degrade homogeneously when collagenase is introduced in solution at a concentration of 0.1-0.3 mg mL À1. Understanding the microstructural and rheological properties of a material near the gel-sol transition enables researchers to improve their insight as to how cells remodel their microenvironment when encapsulated in gels, and more precisely design and manipulate this parameter to improve three-dimensional culture systems.
Digital microfluidic hydrogel microreactors for proteomics
2012
Proteolytic digestion is an essential step in proteomic sample processing. While this step has traditionally been implemented in homogeneous (solution) format, there is a growing trend to use heterogeneous systems in which the enzyme is immobilized on hydrogels or other solid supports. Here, we introduce the use of immobilized enzymes in hydrogels for proteomic sample processing in digital microfluidic (DMF) systems.
Constant-Volume Hydrogel Osmometer: A New Device Concept for Miniature Biosensors
Biomacromolecules, 2002
A new type of biosensor is proposed that combines the recognition properties of "intelligent" hydrogels with the sensitivity and reliability of microfabricated pressure transducers. In the proposed device, analyteinduced changes in the osmotic swelling pressure of an environmentally responsive hydrogel are measured by confining it within a small implantable enclosure between a rigid semipermeable membrane and the diaphragm of a miniature pressure transducer. Proof-of-principle tests of this device were performed in vitro using pH-sensitive hydrogels, with osmotic deswelling data for the same hydrogels used as a benchmark for comparison. The swelling pressure of the hydrogel was accurately determined from osmotic deswelling measurements against reservoirs of known osmotic stress. Values of swelling pressure vs salt concentration measured with a preliminary version of the sensor agree well with osmotic deswelling results. Through modification of the hydrogel with various enzymes or pendant binding moieties, the sensor has the potential to detect a wide range of biological analytes with good specificity.