Ki Wan Bong

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 fr

We present a method called "Lock Release Lithography (LRL)" that utilizes a combination of channel topography, mask design, and pressure-induced channel deformation to form and release particles in a cycled fashion. This technique provides a means for the high-throughput production of particles with complex 3D morphologies and composite particles with spatially configurable chemistries. In this work, we demonstrate a diverse set of functional particles including those displaying heterogeneous sw

Micro sandwiches: The new technique of hydrodynamic focusing lithography (HFL) utilizes stacked microfluidic flows for polymer microparticle synthesis. The method can improve the throughput of flow lithography for multifunctional particles and produce more complex chemically patterned particles (see examples).

Magnetic polymer particles have been used in a wide variety of applications ranging from targeting and separation to diagnostics and imaging. Current synthesis methods have limited these particles to spherical or deformations of spherical morphologies. In this paper, we report the use of stop flow lithography to produce magnetic hydrogel microparticles with a graphical code region, a probe region, and a magnetic tail region. These anisotropic multifunctional magnetic polymer particles are an enh

We present the construction and operation of a compressed-air driven flow system that can be used for a variety of microfluidic applications that require rapid dynamic response and precise control of multiple inlet streams. With the use of inexpensive and readily available parts, we describe how to assemble this versatile control system and further explore its utility in continuous- and pulsed-flow microfluidic procedures for the synthesis and analysis of 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 f

Abstract Piezocatalytic cancer therapy, in which piezoelectric nanomaterials generate reactive oxygen species (ROS) via piezocatalytic redox reactions under mechanical stress, has emerged as an effective strategy for cancer treatment. However, the inherent hypoxia in tumor microenvironments enormously restricts its efficacy. To address this issue, acid‐degradable Janus‐type multicompartmental carriers able to separately encapsulate piezocatalytic gold nanoparticle‐coated poly(ethylene glycol)‐mo

Stimuli-responsive carriers releasing multiple drugs have been researched for synergistic combinatorial cancer treatment with reduced side-effects. However, previously used drug carriers have limitations in encapsulating multiple drug components in a single carrier and releasing each drug independently. In this work, pH-sensitive, multimodulated, anisotropic drug carrier particles are synthesized using an acid-cleavable polymer and stop-flow lithography. The particles exhibit a faster drug relea

Cell-adhesive particles are of significant interest in biotechnology, the bioengineering of complex tissues, and biomedical research. Their applications range from platforms to increase the efficiency of anchorage-dependent cell culture to building blocks to loading cells in heterogeneous structures to clonal-population growth monitoring to cell sorting. Although useful, currently available cell-adhesive particles can accommodate only homogeneous cell culture. Here, we report the design of aniso

Encoded hydrogel particles have attracted attention in diagnostics as these particles can be used for high-performance multiplexed assays. Here, we present encoded tetragonal hydrogel microparticles for multiplexed detection of miRNAs that are strongly related to Alzheimer's disease (AD). The particles are comprised of vertically distinct code and probe regions, and incorporated with quantum dots (QDs) in the code regions. By virtue of the particle geometry, the particles can be synthesized at a

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 microp

Stop Flow Lithography (SFL) is a microfluidic-based particle synthesis method for creating anisotropic multifunctional particles with applications that range from MEMS to biomedical engineering. Polydimethylsiloxane (PDMS) has been typically used to construct SFL devices as the material enables rapid prototyping of channels with complex geometries, optical transparency, and oxygen permeability. However, PDMS is not compatible with most organic solvents which limit the current range of materials

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 po