3D Cell Printed Tissue Analogues: A New Platform for Theranostics

Stem cell theranostics has received much attention for noninvasively monitoring and tracing transplanted therapeutic stem cells through imaging agents and imaging modalities. Despite the excellent regenerative capability of stem cells, their efficacy has been limited due to low cellular retention, low survival rate, and low engraftment after implantation. Three-dimensional (3D) cell printing provides stem cells with the similar architecture and microenvironment of the native tissue and facilitates the generation of a 3D tissue-like construct that exhibits remarkable regenerative capacity and functionality as well as enhanced cell viability. Thus, 3D cell printing can overcome the current concerns of stem cell therapy by delivering the 3D construct to the damaged site. Despite the advantages of 3D cell printing, the in vivo and in vitro tracking and monitoring of the performance of 3D cell printed tissue in a noninvasive and real-time manner have not been thoroughly studied. In this review, we explore the recent progress in 3D cell technology and its applications. Finally, we investigate their potential limitations and suggest future perspectives on 3D cell printing and stem cell theranostics.116Nsciescopu

The involvement of AMPK/GSK3-beta signals in the control of metastasis and proliferation in hepato-carcinoma cells treated with anthocyanins extracted from Korea wild berry Meoru

BACKGROUND: Activation of the Wnt pathway is known to promote tumorigenesis and tumor metastasis, and targeting Wnt pathway inhibition has emerged as an attractive approach for controlling tumor invasion and metastasis. The major pathway for inhibiting Wnt is through the degradation of β-catenin by the GSK3-beta/CK1/Axin/APC complex. It was found that Hep3B hepato-carcinoma cells respond to anthocyanins through GSK3-beta-induced suppression of beta-catenin; however, they cannot dephosphorylate GSK3-beta without AMPK activation. METHODS: We tested the effects of anthocyanins on proliferation and apoptosis by MTT and Annexin V-PI staining in vitro. Mouse xenograft models of hepato-carcinomas were established by inoculation with Hep3B cells, and mice were injected with 50 mg/kg/ml of anthocyanins. In addition, protein levels of p-GSK3-beta, beta-catenin, p-AMPK, MMP-9, VEGF, and Ang-1 were also analyzed using western blot. RESULTS: Anthocyanins decrease phospho-GSK3-beta and beta-catenin expression in an in vivo tumor xenograft model, increase AMPK activity in this model, and inhibit cell migration and invasion, possibly by inhibiting MMP-2 (in vitro) and the panendothelial marker, CD31 (in vivo). To elucidate the role of the GSK3-beta/beta-catenin pathway in cancer control, we conditionally inactivated this pathway, using activated AMPK for inhibition. Further, we showed that AMPK siRNA treatment abrogated the ability of anthocyanins to control cell proliferation and metastatic potential, and Compound C, an AMPK inhibitor, could not restore GSK3-beta regulation, as exhibited by anthocyanins in Hep3B cells. CONCLUSION: These observations imply that the AMPK-mediated GSK3-beta/beta-catenin circuit plays crucial roles in inhibiting cancer cell proliferation and metastasis in anthocyanin-treated hepato-carcinoma cells of Meoru origin

ZnO Nanorod Biosensor for Highly Sensitive Detection of Specific Protein Binding

We report on the fabrication of electrical biosensors based on functionalized ZnO nanorod surfaces with biotin for highly sensitive detection of biological molecules. Due to the clean interface and easy surface modification, the ZnO nanorod sensors can easily detect streptavidin binding down to a concentration of 25 nM, which is more sensitive than previously reported one-dimensional (1D) nanostructure electrical biosensors. In addition, the unique device structure with a micrometer-scale hole at the center of the ZnO nanorod's conducting channel reduces the leakage current from the aqueous solution, hence enhancing device sensitivity. Moreover, ZnO nanorod field-effect-transistor (FET) sensors may open up opportunities to create many other oxide nanorod electrical sensors for highly sensitive and selective real-time detection of a wide variety of biomolecules.The authors thank Prof. Hee Cheul Choi at POSTECH for helpful discussion. This work was supported by the Korea Research Foundation Grant (KRF-2003-041-C00132)

Duplex-specific nuclease efficiently removes rRNA for prokaryotic RNA-seq

Next-generation sequencing has great potential for application in bacterial transcriptomics. However, unlike eukaryotes, bacteria have no clear mechanism to select mRNAs over rRNAs; therefore, rRNA removal is a critical step in sequencing-based transcriptomics. Duplex-specific nuclease (DSN) is an enzyme that, at high temperatures, degrades duplex DNA in preference to single-stranded DNA. DSN treatment has been successfully used to normalize the relative transcript abundance in mRNA-enriched cDNA libraries from eukaryotic organisms. In this study, we demonstrate the utility of this method to remove rRNA from prokaryotic total RNA. We evaluated the efficacy of DSN to remove rRNA by comparing it with the conventional subtractive hybridization (Hyb) method. Illumina deep sequencing was performed to obtain transcriptomes from Escherichia coli grown under four growth conditions. The results clearly showed that our DSN treatment was more efficient at removing rRNA than the Hyb method was, while preserving the original relative abundance of mRNA species in bacterial cells. Therefore, we propose that, for bacterial mRNA-seq experiments, DSN treatment should be preferred to Hyb-based methods.

Heteroepitaxal fabrication and structural characterization of ultrafine GaN/ZnO coaxial nanorod heterostructures

We report on heteroepitaxial fabrication and structural characterizations of ultrafine GaN/ZnO coaxial nanorod heterostructures. The coaxial nanorod heterostructures were fabricated by epitaxial growth of a GaN layer on ultrafine ZnO nanorods. Epitaxial growth and precise control of GaN overlayer thickness were obtained by low pressure metalorganic vapor-phase epitaxy. ZnO nanorods grown on Si and sapphire substrates using catalyst-free metalorganic chemical vapor deposition exhibited diameters as small as 7 nm. Furthermore, structural properties of the coaxial nanorod heterostructures were investigated using both synchrotron-radiation x-ray diffraction and high resolution transmission electron microscopy. (C) 2004 American Institute of Physics

Electroreflectance Study of Zn0.8Mg0.2O/ZnO Nanorod Heterostructures

ZnO, due to its large exciton binding energy which enables excitonic recombination at room temperature, is attracting much attention as a material for room-temperature UV devices. In particular, ZnO nanorod has attracted a great deal of attention because of the commercial interest in short-wavelength semiconductor laser diodes and nanometer-scale electronic devices. Zn0.8Mg0.2O/ZnO nanorod heterostructures were grown by metal-organic vapor-phase epitaxy on catalyst-free ZnO nanorods. Electro reflectance measurements were carried out at temperatures between 90 K and 295 K and compared with photoluminescence data. Quantum confinement effects in Zn0.8Mg0.2O/ZnO nanorod heterostructures were observed.This work was supported by KOSEF through the Quantum Photonic Science Research Center at Hanyang University and by MOST through the National R&D Project for Nano Science