Selective Cell-Cell Adhesion Regulation via Cyclic Mechanical Deformation Induced by Ultrafast Nanovibrations.

The adoption of dynamic mechanomodulation to regulate cellular behavior is an alternative to the use of chemical drugs, allowing spatiotemporal control. However, cell-selective targeting of mechanical stimuli is challenging due to the lack of strategies with which to convert macroscopic mechanical movements to different cellular responses. Here, we designed a nanoscale vibrating surface that controls cell behavior via selective repetitive cell deformation based on a poroelastic cell model.

Preparation of Stretchable Nanofibrous Sheets with Sacrificial Coaxial Electrospinning for Treatment of Traumatic Muscle Injury.

Traumatic muscle injury with massive loss of muscle volume requires intramuscular implantation of proper scaffolds for fast and successful recovery. Although many artificial scaffolds effectively accelerate formation and maturation of myotubes, limited studies are showing the therapeutic effect of artificial scaffolds in animal models with massive muscle injury. In this study, improved myotube differentiation is approved on stepwise stretched gelatin nanofibers and applied to damaged muscle recovery in an animal model.

Gold nanospheres and nanorods for anti-cancer therapy: comparative studies of fabrication, surface-decoration, and anti-cancer treatments.

Various gold nanoparticles have been explored as cancer therapeutics because they can be widely engineered for use as efficient drug carriers and diagnostic agents, and in photo-irradiation therapy. In the current review, we focused on shape-dependent biomedical applications of gold nanoparticles including gold nanospheres and nanorods. Fabrication and functionalization strategies of two different gold nanoparticles for anti-cancer therapy are introduced and the distinguishing performance depending on the shape is discussed to suggest the best carrier shape for specific applications.

Biomaterials and controlled release strategy for epithelial wound healing.

The skin and cornea are tissues that provide protective functions. Trauma and other environmental threats often cause injuries, infections and damage to these tissues, where the degree of injury is directly correlated to the recovery time. For example, a superficial skin or corneal wound may recover within days; however, more severe injuries can last up to several months and may leave scarring.

Electrospining of Nanofibrous Meshes Composed of Hypromellose and Poly(vinyl alcohol) for One-Day Release of Cationic Peptide.

Various biocompatible polymers have been developed using electrospun nanofibers for local drug delivery matrices, but many of them are non-FDA-approved polymers or chemicals. Material safety should be considered in biomedical devices, but the effectiveness of electrospun nanofibers is limited with only the approved chemicals. Therefore, we considered the material in FDA-approved polymers and solvents and developed nanofibers using the general additives in the pharmaceutical industry, such as hypromellose, poly(vinyl alcohol) (PVA), and Gellan.

Coaxial Hydro-Nanofibrils for Self-Assembly of Cell Sheets Producing Skin Bilayers.

Bilayered cell sheets were fabricated with coaxial hydro-nanofibrils for three-dimensional (3D) cultivation in a biomimetic environment. Polycaprolactone (PCL) was electrospun and hydrolyzed to release fragmented nanofibrils (NF) in an alkaline condition. Methacrylated gelatin (GelMA) was adsorbed and phototethered on the surface of the fibrils to prepare coaxial NF composed of hydrophilic shells and hydrophobic cores.

Atom Transfer Radical Polymerization of Multishelled Cationic Corona for the Systemic Delivery of siRNA.

We propose an effective siRNA delivery system by preparing poly(DAMA-HEMA)-multilayered gold nanoparticles using multiple surface-initiated atom transfer radical polymerization processes. The polymeric multilayer structure is characterized by transmission electron microscopy, matrix-associated laser desorption/ionization time-of-flight mass spectrometry, UV-vis spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, and ζ-potential. The amount of siRNA electrostatically incorporated into the nanoparticle can be tuned by the number of polymeric shells, which in turn influences the cellular uptake and gene silencing effect.

Doxorubicin encapsulated clicked gold nanoparticle clusters exhibiting tumor-specific disassembly for enhanced tumor localization and computerized tomographic imaging.

Gold nanoparticles (AuNPs) and matrix metalloproteinase (MMP)-2 cleavable peptides are clicked into gold nanoparticle clusters (AuNCs) for enhanced drug localization and micro computerized tomography (μCT) theranostic of tumors. AuNPs are co-functionalized with doxorubicin (DOX) and an azide-terminated polymer (DOX/N3@AuNPs), and the DOX/N3@AuNPs are associated into DOX@AuNCs in the presence of an alkyne-terminated MMP-2 cleavable peptide (alkyne-peptide-alkyne; APA) by click chemistry. MMP-2-dependent dissociation shows that DOX@AuNCs are highly sensitive to the MMP-2 and are almost completed digested into single nanoparticles.

Clustering siRNA conjugates for MMP-responsive therapeutics in chronic wounds of diabetic animals.

The MMP-responsive breakdown of siRNA clusters was translated to site-specific gene transfection and enhanced wound healing in diabetic ulcers. MMP-2 siRNA was chemically tethered to the end of multi-armed PEG via MMP-cleavable linkers (4PEG-siRNA) and subsequently clustered into submicron particles complexed with LPEI. 4PEG-siRNA was more tightly complexed with LPEI and the associated cluster showed higher resistance against RNase attack, in comparison to naked siRNA.

Electrospun Nanofibrous Sheets for Selective Cell Capturing in Continuous Flow in Microchannels.

Electrospun nanofibrous meshes were surface-modified for selective capturing of specific cells from a continuous flow in PDMS microchannels. We electrospun nanofibrous mats composed of poly(ε-carprolactone) (PCL) and amine-functionalized block copolymers composed of PCL and poly(ethylenimine) (PEI). A mixture of biotinylated PEG and blunt PEG was chemically tethered to the nanofibrous mats via the surface-exposed amines on the mat.

Multilayered electrospun fibrous meshes for restenosis-suppressing metallic stents.

Nanofiber is a flexible and highly porous mesh that is advantageous for coating bare metal stent and local drug delivery. Herein, we developed drug-eluting stent coated with PCL/PU blending coaxial nanofiber for controlling drug release manner and suppressing in-stent restenosis, which is a representative side effect of stenting surgery. The shell of coaxial electrospun nanofibrous are composed of poly (ε-caprolactone) (PCL) and polyurethane (PU) for biodegradability and elasticity to the polymeric coating of stent.

High-yield clicking and dissociation of doxorubicin nanoclusters exhibiting differential cellular uptakes and imaging.

Gold nanoparticles (AuNPs) and quantum dots (Qdots) were clicked into doxorubicin nanoclusters that showed enzyme-dependent dissociation behaviors for differential cellular uptakes and imaging. The AuNPs were co-functionalized with doxorubicin (DOX) and azide-terminated polymer (DOX/azide@AuNP), while an enzyme-cleavable peptide and alkyne-terminated polymer were sequentially conjugated on Qdot surface (Alkyne-MMP@Qdot). Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and fluorescence imaging detected the azide and alkyne groups on DOX/azide@AuNP and Alkyne-MMP@Qdot, respectively, and the click-reactivity was also confirmed.

Antibacterial Nanofibrous Mats Composed of Eudragit for pH-Dependent Dissolution.

A pH-responsive nanofibrous mesh was prepared for the controlled release of antibiotics in response to pH changes. Eudragit EPO (EPO) and Eudragit L100 (L100) were injected through inner and outer needle and simultaneously electrospun through coaxial nozzles composed of inner and outer needles. Various amounts of EPO and L100 were coejected with tetracycline through the needle and simultaneously electrospun to the fibrous meshes.

Therapeutic applications of electrospun nanofibers for drug delivery systems.

Electrospun nanofiber drug delivery systems have been studied using various techniques. Herein, we describe the fabrication of a drug-incorporating nanofiber. Drugs, such as proteins, peptide, antibodies, and small molecule drugs, can be loaded within or on the surface of nanofibers according to their properties.

Multifunctional nanorods serving as nanobridges to modulate T cell-mediated immunity.

Electrodeposited nanorods serving as multivalent bridges were fabricated and surface-decorated with ligands for immune cells. Gold and nickel solutions were sequentially electrodeposited on nanoporous anodized disc templates and the template was dissolved to retrieve bisegmented nanorods with different lengths. Gold and nickel segmented nanorods were surface-immobilized with mannose and RGD peptides to prepare immune-cell recruiting nanorods.

Electrospun catechol-modified poly(ethyleneglycol) nanofibrous mesh for anti-fouling properties.

Electrospun nanofibrous mesh composed of catechol-conjugated 8-arm PEG (8cPEGa) and thiolated PLGA (PLGA-SH) was prepared with various blending ratios of PLGA-SH and 8cPEGa. Cross-linking between the two polymers via catechol-thiol reactions and catechol-catechol conjugation was performed by brief soaking with sodium periodate solution. The chemical conjugation of PLGA-SH and 8cPEGa in the nanofibrous mesh was confirmed by the spectral differences of the Raman spectra and changes in the thermal properties.

Dexamethasone-incorporated nanofibrous meshes for antiproliferation of smooth muscle cells: thermally induced drug-loading strategy.

Pluronic-immobilized nanofibrous meshes were tailored for thermally induced incorporation of dexamethasone. A diblock copolymer composed of poly(e-caprolactone)-poly (ethyleneglycol) (NH(2)) (PCL-PEG (NH(2))) was electrospun to a nanofibrous mesh, and Pluronic was subsequently surface-immobilized on the mesh in aqueous phase. Surface-wettability analysis and (1)H NMR spectroscopy confirmed surface-decoration of nanofibrous meshes with Pluronic moieties depending on the blend ratios of PCL-PEG(NH(2)).

[Effects of a problem-based learning program on health education for elders].

Purpose: The purposes of this study was to analyze the effects of a health education program using problem-based learning on health related knowledge, behavior, and quality of life in elderly people.

Methods: The participants included 44 elders, of whom 23 took the health education program and 21 did not. All participants were over 60 yr of age and were selected from residents of nursing homes or participants in activities of social welfare facilities in Jeju Province.