Air-through-precursor suction-augmented replica molding for fabrication of anisotropic microparticles in gas-impermeable molds.

Replica molding (REM) is a powerful technique for fabricating anisotropic microparticles. Current REM methods rely on the use of gas-permeable molds for defect-free castings and facile particle recovery. However, they often encounter limitations on either technical accessibility or producible particle diversity.

Multiplex genotyping of SNPs in genomic DNA via hydrogel-based assay mediated with MutS and polyethylene glycol.

The simultaneous genotyping of multiple single nucleotide polymorphisms (SNPs) in genomic DNA derived from organisms holds significant potential for applications such as precision medicine and food product authentication. However, conventional assay technologies including qPCR-based techniques, microarrays, and hydrogel-based assays face limitations in efficient multiplexing of SNPs, particularly for large-size DNA beyond kilobase scales, due to constraints in multiplex capability, specificity, or sensitivity. In this study, a hydrogel-based multiplex SNP genotyping platform specifically designed for genomic DNA is presented.

Multiplex Assay for Rapid Detection and Analysis of Nucleic Acid Using Barcode Receptor Encoded Particle (BREP).

Several multiplex nucleic acid assay platforms have been developed in response to the increasing importance of nucleic acid analysis, but these assays should be optimized as per the requirements of point-of-care for clinical diagnosis. To achieve rapid and accurate detection, involving a simple procedure, we propose a new concept in the field of nucleic acid multiplex assay platforms using hydrogel microparticles, called barcode receptor-encoded particles (BREPs). The BREP assay detects multiple targets in a single reaction with a single fluorophore by analyzing graphically encoded hydrogel particles.

High-Resolution Surface Replication of Living Organisms using Air-Through-Precursor Suction-Augmented Replica Molding.

Replica molding is widely used to reproduce the surface microstructures that provide living organisms with distinct and useful functions. However, the existing methods are limited by the low resolution resulting from the air trapped in the structures during precursor solution loading. This study investigated replica molding with an air-through-precursor suction (APS) process, which used a degassed polydimethylsiloxane substrate to remove the trapped air through the precursor solution.

Encoded hydrogel microparticles with universal mismatch-incorporated DNA probes for highly specific multiplex detection of SNPs.

Hydrogel microparticle-based nucleic acid assays are an attractive detection platform based on their multiplexing capabilities with high sensitivity and specificity. A particular area of interest is single-nucleotide polymorphism (SNP) sensing, where multiple SNPs should be identified in a highly reliable yet economical manner. However, hydrogel microparticles leveraging probe-target hybridization as a key mechanism are hampered by small duplex stability differences arising from single base-pair mismatch.

Hydrogel-based hybridization chain reaction (HCR) for detection of urinary exosomal miRNAs as a diagnostic tool of prostate cancer.

Although urinary exosomal microRNAs (miRNAs) have recently emerged as potential biomarkers, clinical applications are still limited due to their low concentration in small volumes of clinical samples. Therefore, the development of a non-invasive, specific diagnostic tool, along with profiling exosomal miRNA markers from urine, remains a significant challenge. Here, we present hydrogel-based hybridization chain reaction (HCR) for multiplex signal amplification to detect urinary exosomal miRNAs from human clinical samples.

Discontinuous Dewetting in a Degassed Mold for Fabrication of Homogeneous Polymeric Microparticles.

Discontinuous dewetting (DD) is an attractive technique that enables the production of large liquid arrays in microwells and is applicable to the synthesis of anisotropic microparticles with complex morphologies. However, such loading of liquids into microwells presents a significant challenge, as the liquids used in this technique should exhibit low mold surface wettability. This study introduces DD in a degassed mold (DM), a simple yet powerful technique that achieves uniform loading of microparticle precursors into large microwell arrays within 1 min.

Photopolymerization-Based Synthesis of Uniform Magnetic Hydrogels and Colorimetric Glucose Detection.

Magnetic hydrogels have been commonly used in biomedical applications. As magnetite nanoparticles (MNPs) exhibit peroxidase enzyme-like activity, magnetic hydrogels have been actively used as signal transducers for biomedical assays. Droplet microfluidics, which uses photoinitiated polymerization, is a preferred method for the synthesis of magnetic hydrogels.

Precipitation-based colorimetric multiplex immunoassay in hydrogel particles.

Despite a growing demand for more accessible diagnostic technologies, current methods struggle to simultaneously detect multiple analytes with acceptable sensitivity and portability. Colorimetric assays have been widely used due to their simplicity of signal readout, but the lack of multiplexibility has been a perpetual constraint. Meanwhile, particle-based assays offer multiplex detection by assigning an identity code to each analyte, but they often require lab-based equipment unsuitable for portable diagnostics.

Phosphorylcholine-based encoded hydrogel microparticles with enhanced fouling resistance for multiplex immunoassays.

Due to the growing interest in multiplex protein detection, encoded hydrogel microparticles have received attention as a possible path to high performance multiplex immunoassays through a combination of high multiplexing capability and enhanced binding kinetics. However, their practical operation in real complex samples is still limited because polyethylene glycol, which is the main component of hydrogel particles, suffers from oxidative damage and relatively high fouling properties in biochemical solutions. Here, we introduce poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC)-based encoded hydrogel microparticles to perform fouling-resistant multiplex immunoassays, where the anti-fouling characteristics are attributed to the zwitterionic PMPC.

Direct Conjugation of Streptavidin to Encoded Hydrogel Microparticles for Multiplex Biomolecule Detection with Rapid Probe-Set Modification.

Encoded hydrogel microparticles synthesized via flow lithography have drawn attention for multiplex biomarker detection due to their high multiplex capability and solution-like hybridization kinetics. However, the current methods for preparing particles cannot achieve a flexible, rapid probe-set modification, which is necessary for the production of various combinations of target panels in clinical diagnosis. In order to accomplish the unmet needs, streptavidin was incorporated into the encoded hydrogel microparticles to take advantage of the rapid streptavidin-biotin interactions that can be used in probe-set modification.

Elimination of Unreacted Acrylate Double Bonds in the Polymer Networks of Microparticles Synthesized via Flow Lithography.

Flow lithography (FL), a versatile technique used to synthesize anisotropic multifunctional microparticles, has attracted substantial interest, given that the resulting particles with complex geometries and multilayered biochemical functionalities can be used in a wide variety of applications. However, after this process, there are double bonds remaining from the cross-linkable groups of monomers. The unreacted cross-linkable groups can affect the particles' biochemical properties.

Affinity-Enhanced CTC-Capturing Hydrogel Microparticles Fabricated by Degassed Mold Lithography.

Technologies for the detection and isolation of circulating tumor cells (CTCs) are essential in liquid biopsy, a minimally invasive technique for early diagnosis and medical intervention in cancer patients. A promising method for CTC capture, using an affinity-based approach, is the use of functionalized hydrogel microparticles (MP), which have the advantages of water-like reactivity, biologically compatible materials, and synergy with various analysis platforms. In this paper, we demonstrate the feasibility of CTC capture by hydrogel particles synthesized using a novel method called degassed mold lithography (DML).

Post-synthesis functionalized hydrogel microparticles for high performance microRNA detection.

Encoded hydrogel microparticles, synthesized by Stop Flow Lithography (SFL), have shown great potential for microRNA assays for their capability to provide high multiplexing capacity and solution-like hybridization kinetics. However, due to the low conversion of copolymerization during particle synthesis, current hydrogel microparticles can only utilize ∼10% of the input probes that functionalize the particles for miRNA assay. Here, we present a novel method of functionalizing hydrogel microparticles after particle synthesis by utilizing unconverted double bonds remaining inside the hydrogel particles to maximize functional probe incorporation and increase the performance of miRNA assay.

Multiplexed immunoassay using post-synthesis functionalized hydrogel microparticles.

In response to a growing demand for simultaneous detection of multiple proteins in a single sample, multiplex immunoassay platforms have emerged at the forefront of proteomic analysis. In particular, detections using graphically encoded hydrogel microparticles synthesized via flow lithography have received attention for integrating a hydrogel, a substrate that can provide enhanced kinetics and high loading capacity, into the bead-based multiplex platform. Currently, the method of microparticle functionalization involves copolymerization of antibodies with the gel during particle synthesis.

Implantable Photothermal Agents based on Gold Nanorods-Encapsulated Microcube.

Gold nanorods (GNRs) are of great interest in cancer therapy given their ability to ablate tumor cells using deep tissue-penetrating near-infrared light. GNRs coated with tumor-specific moieties have the potential to target tumor tissue to minimize damage to normal tissue. However, perfect targeting is difficult to achieve given that nanoparticles could be broadly dispersed inside the body.

Microfluidic fabrication of biocompatible poly(N-vinylcaprolactam)-based microcarriers for modulated thermo-responsive drug release.

Various thermo-responsive polymers have been developed for controlled drug delivery upon the local application of external heat. The development of thermo-responsive polymers with high biocompatibility and tunable thermo-sensitivity is crucial for safe and efficient therapeutic application. In this study, thermo-responsive drug carriers featuring tunable thermo-sensitivities were synthesized using biocompatible poly(N-vinyl caprolactam) (PVCL) and stop-flow lithography.