Biomedical subjects

Jinho Hyun

Publications and source records attributed to Jinho Hyun.

5 recordsLinked to original sources

PubMed2006

Micropatterning of cell-repellent polymer on a glass substrate for the highly resolved virus microarray.

The development of a simple and easily accessible method to control cellular behavior under a spatially controlled surface is critical for fundamental studies in biotechnology. We fabricated a microarray of Spodoptera frugiperda 9 (Sf9) cells on a glass surface by microcontact printing cell-repellent polymeric molecules of poly(ethylene glycol)-branched-poly(methyl methacrylate) as a template for cell micropatterning. The polymer micropatterns enabled the stable confinement of Sf9 cells on the surface, resulting in the formation of a cell microarray. Subsequently, the patterned Sf9 cells were infected with recombinant baculovirus modified with green fluorescent protein (GFP) to form a virus microarray, and GFP expression in the virus microarray was verified with confocal fluorescence microscopy.

Animals↗

PubMed2005

Patterning cells in highly deformable microstructures: effect of plastic deformation of substrate on cellular phenotype and gene expression.

We describe the fabrication of deformable microstructures by low-pressure-soft-microembossing (muSEmb) that provides in vitro experimental "test-beds" to investigate the interplay of mechanical and chemical stimuli on cell behavior in a highly controlled environment. Soft microembossing exploits the softness and plasticity of parafilm to fabricate microstructures by pressing a silicon master or an elastomeric poly(dimethylsiloxane) stamp into the parafilm. We demonstrate that a protein-resistant comb polymer can be printed into the raised features of the embossed microstructures, which imparts protein, and hence cell resistance to those regions of the microstructures. These two features of our fabrication methodology-microembossing followed by spatially selective transfer of a nonfouling polymer-forms the core of our strategy to pattern cells within the parafilm microstructures, such that the cells are confined within bottoms of the microstructures. Cell culture experiments demonstrated the preferential cell attachment of NIH 3T3 fibroblasts to the fibronectin (FN) micropatterns by immunofluorescence microscopy. The actin cytoskeleton realigned along the axis of applied mechanical stress, and stretched cells showed altered gene expression of cytoskeletal and matrix proteins in response to mechanical deformation. The use of parafilm as a substrate and muSEmb as a fabrication method provides a simple and widely accessible methodology to investigate cellular behavior under well-defined conditions of plastic deformation and surface ligand density.

Animals↗

PubMed2004

Capture and release of proteins on the nanoscale by stimuli-responsive elastin-like polypeptide "switches".

This article describes the fabrication and characterization of stimulus-responsive elastin-like polypeptide (ELP) nanostructures grafted onto omega-substituted thiolates that were patterned onto gold surfaces by dip-pen nanolithography (DPN). In response to external stimuli such as changes in temperature or ionic strength, ELPs undergo a switchable and reversible, hydrophilic-hydrophobic phase transition at a lower critical solution temperature (LCST). We exploited this phase transition behavior to reversibly immobilize a thioredoxin-ELP (Trx-ELP) fusion protein onto the ELP nanopattern above the LCST. Subsequent binding of an anti-thioredoxin monoclonal antibody (anti-Trx) to the surface-captured thioredoxin showed the presentation of the immobilized protein in a sterically accessible orientation in the nanoarray. We also showed that the resulting Trx-ELP/anti-Trx complex formed above the LCST could be reversibly dissociated below the LCST. These results demonstrate the intriguing potential of ELP nanostructures as generic, reversible, biomolecular switches for on-chip capture and release of a small number (order 100-200) of protein molecules in integrated, nanoscale bioanalytical devices. We also investigated the molecular mechanism underlying this switch by measuring the height changes that accompany the binding and desorption steps and by adhesion force spectroscopy using atomic force microscopy.

Elastin↗

PubMed2004

Enzymatic nanolithography of a self-assembled oligonucleotide monolayer on gold.

This paper describes a simple strategy to biochemically manipulate a surface at the nanoscale by enzyme dip-pen nanolithography using an endonuclease (DNase I) that is directly patterned on a self-assembled monolayer presenting a terminal oligonucleotide. Physisorbed nanopatterns of DNase I carried out nanoscale enzymology at the surface creating oligonucleotide patterns with the fidelity of the patterned enzyme because of the affinity of the enzyme for the immobilized, oligonucleotide substrate.

Deoxyribonuclease I↗

PubMedDate not supplied

Polymer-templated microarrays for highly reliable plaque purification.

To infect cells with a particular multiplicity of infection, it is essential to know the concentration of virus in the inoculum. Here we describe a highly reliable and controllable method for plaque purification using cell-repellent surfaces micropatterned on the substrate. Micropatterning of localized chemical or biochemical domains has the potential to become a powerful tool in controlling the seeding of cells. The cell array was reliably fabricated with micropatterned surfaces, and the number of cells in a pattern was easily controlled by the cell density in the media and micropattern size. The cell micropatterns were infected with baculoviruses to form an array of virus plaques. GFP-modified and wild-type baculoviruses were used to verify the feasibility of purifying a specific plaque. Using confocal microscopy, GFP-expressing plaques were readily selectable and removable.

Animals↗