ABSTRACT
Endogenous bioelectric signaling and the extracellular matrix (ECM) are factors that have a great effect on the performance of cellular functions. Presenting an experimental platform to confirm the synergy effects of an electrical stimulation, which simulates endogenous bioelectricity, and nanopatterns that can be precisely fabricated in various patterns sizes makes it possible to consider those factors effectively. Herein, we have performed a comparison of cellular response to each of general electrical stimulation and biomimetic electrical stimulation (BES) and demonstrated the synergy effects of electrical stimulation and ECM-mimetic nanopatterns. BES has provided the most remarkable proliferation among different types of electrical stimulation and upregulated the behavior of cells through synergy effects with ECM-mimetic nanopatterns. Thus, it is believed that using the synergy effects of BES and ECM-like nanopatterns has broad applications in the biomedical field, such as cell culture with electrical stimulation, induction of cell growth, tissue repair, etc.
Subject(s)
Biomimetics , Biosensing Techniques , Electric Stimulation , Extracellular Matrix , Wound HealingABSTRACT
Whispering gallery modes (WGMs) around the liquid crystal droplets are sensitive to the director orientation at the interface. An electric field was applied for changing the director orientation of a nematic liquid crystal droplet surrounded by polydimethylsiloxane (PDMS), which induced vertical director orientation at the interface. WGMs were shifted by varying the electric field intensity, and WGM shift-dependent director response was calculated. From this calculation we obtained the extrapolation length of 0.35 ± 0.02 µm. These results indicate that WGM sensitivity can be used for obtaining the surface properties of liquid crystals.
ABSTRACT
A compartmentalized multidomain alignment state of a layer of liquid crystal display is achieved using an ultrathin, highly transparent, and ultrafast-responsive alignment layer fabricated by a simple method. The ultrathin alignment layer consists of a self-assembled oligomer layer of poly(dimethylsiloxane) (PDMS) formed by utilizing the oligomers that diffuse out from a PDMS elastomer stamp during a contact printing process.
ABSTRACT
Cis-trans photoconversion behaviors of 4-dimethylaminoazobenzenecarboxylate (4DAzC) on gold nanoparticle surfaces have been investigated by means of Raman spectroscopy. The vibrational features indicated that both the cis- and trans-conformation should coexist after the adsorption on gold nanoparticle surfaces. After the irradiation of the blue light, the intensities of the cis-form peaks were found to decrease on gold. Our work can demonstrate that Raman spectroscopy can be utilized in studying the photoconversion of azobenzene-containing self-assembled monolayers fabricated on metal surfaces.
ABSTRACT
On cooling through the isotropic-to-nematic phase transition in a cell whose substrates induce a large pretilt angle theta0 from the vertical direction, but with no preferential azimuthal orientation, tilt domains appear. The boundary walls between reverse tilt domains are found to be bendlike and twistlike when theta0(T=TNI) is sufficiently large just below the isotropic-nematic phase transition temperature TNI--i.e., for a nearly planar orientation. Here the director becomes planar approximately midway through the wall, and we refer to this type of wall as "polar horizontal," which is topologically stable. However, if theta0(T=TNI) is sufficiently small just below TNI--i.e., closer to vertical orientation--a splay like and twistlike domain wall obtains, where the director is vertically oriented approximately midway through the wall; we refer to this type of wall as "polar vertical," whose stability depends on the anchoring. On cooling through the nematic phase, the pretilt angle theta0 decreases, with the director aligning closer to the vertical orientation. Nevertheless, the structures of both types of domain walls remain unchanged on variation of theta0 with temperature owing to topological constraints and also are unchanged after the application and removal of a large electric field. We examine the structure of domain walls for the liquid crystal ZLI-4330 (Merck) as a function of pretilt angle theta0(T=TNI) and calculate a critical value theta0c(T=TNI) of the pretilt angle just below TNI for which the predominance of domain walls crosses over from polar horizontal to polar vertical.
