Fluorescent Liquid Metal As a Transformable Biomimetic Chameleon

Liquid metal (LM) is of core interest for a wide variety of newly emerging areas. However, the functional materials thus made so far by LM only could display a single silver-white appearance. In this study, colorful LM marbles working like a transformable biomimetic robot were proposed for the first time and fabricated from LM droplets through encasing them with fluorescent nanoparticles. We demonstrated that this unique LM marble can be manipulated into various stable magnificent appearances as one desires and then split and merge among different colors. Such multifunctional LM is capable of responding to the outside electric stimulus and realizing shape transformation and discoloration behaviors as well. Furthermore, the electric stimuli has been successfully introduced to trigger the release of nano/microparticles from the LM, and the mechanism lying behind was clarified. The present fluorescent LM was expected to offer important opportunities for diverse applications, especially in a wide range of functional smart material areas

Fluorescent Liquid Metal As a Transformable Biomimetic Chameleon

Liquid metal (LM) is of core interest for a wide variety of newly emerging areas. However, the functional materials thus made so far by LM only could display a single silver-white appearance. In this study, colorful LM marbles working like a transformable biomimetic robot were proposed for the first time and fabricated from LM droplets through encasing them with fluorescent nanoparticles. We demonstrated that this unique LM marble can be manipulated into various stable magnificent appearances as one desires and then split and merge among different colors. Such multifunctional LM is capable of responding to the outside electric stimulus and realizing shape transformation and discoloration behaviors as well. Furthermore, the electric stimuli has been successfully introduced to trigger the release of nano/microparticles from the LM, and the mechanism lying behind was clarified. The present fluorescent LM was expected to offer important opportunities for diverse applications, especially in a wide range of functional smart material areas

Using Dicationic Ion-Pairing Compounds To Enhance the Single Cell Mass Spectrometry Analysis Using the Single-Probe: A Microscale Sampling and Ionization Device

A unique mass spectrometry (MS) method has been developed to determine the negatively charged species in live single cells using the positive ionization mode. The method utilizes dicationic ion-pairing compounds through the miniaturized multifunctional device, the single-probe, for reactive MS analysis of live single cells under ambient conditions. In this study, two dicationic reagents, 1,5-pentanediyl-bis­(1-butylpyrrolidinium) difluoride (C₅(bpyr)₂F₂) and 1,3-propanediyl-bis­(tripropylphosphonium) difluoride (C₃(triprp)₂F₂), were added in the solvent and introduced into single cells to extract cellular contents for real-time MS analysis. The negatively charged (1– charged) cell metabolites, which form stable ion-pairs (1+ charged) with dicationic compounds (2+ charged), were detected in positive ionization mode with a greatly improved sensitivity. We have tentatively assigned 192 and 70 negatively charged common metabolites as adducts with (C₅(bpyr)₂F₂) and (C₃(triprp)₂F₂), respectively, in three separate SCMS experiments in the positive ion mode. The total number of tentatively assigned metabolites is 285 for C₅(bpyr)₂F₂ and 143 for C₃(triprp)₂F₂. In addition, the selectivity of dicationic compounds in the complex formation allows for the discrimination of overlapped ion peaks with low abundances. Tandem (MS/MS) analyses at the single cell level were conducted for selected adduct ions for molecular identification. The utilization of the dicationic compounds in the single-probe MS technique provides an effective approach to the detection of a broad range of metabolites at the single cell level

The Single-Probe: A Miniaturized Multifunctional Device for Single Cell Mass Spectrometry Analysis

We have developed a new mass spectrometry (MS) technology, the Single-probe MS, capable of real-time, in situ metabolomic analysis of individual living cells. The Single-probe is a miniaturized multifunctional sampling and ionization device that is directly coupled to the mass spectrometer. With a sampling tip smaller than individual eukaryotic cells (<10 μm), the Single-probe can be inserted into single cells to sample the intracellular compounds for real-time MS analysis. We have used the Single-probe to detect several cellular metabolites and the anticancer small molecules paclitaxel, doxorubicin, and OSW-1 in individual cervical cancer cells (HeLa). Single cell mass spectrometry (SCMS) is an emerging scientific technology that could reshape the analytical science of many research disciplines, and the Single-probe MS technology is a novel method for SCMS that, through its accessible fabrication protocols, can be broadly applied to different research areas

Nanoparticle-Mediated Intracellular Delivery Enables Cryopreservation of Human Adipose-Derived Stem Cells Using Trehalose as the Sole Cryoprotectant

In this study, pH responsive genipin-cross-linked Pluronic F127-chitosan nanoparticles (GNPs) was synthesized to encapsulate trehalose for intracellular delivery to cryopreserve primary human adipose-derived stem cells (hADSCs). Trehalose is a disaccharide of glucose used by lower organisms to survive extreme cold in nature and has been used to cryopreserve various biomacromolecules. However, it does not enter mammalian cells because of its highly hydrophilic nature, and has only been used in combination with other cell-penetrating cryoprotectants (such as dimethyl sulfoxide, DMSO) to cryopreserve mammalian cells. Our data show that trehalose can be efficiently encapsulated in our GNPs for intracellular delivery, which enables cryopreservation of primary hADSCs using the nontoxic sugar as the sole cryoprotectant. This capability is important because the conventional approach of cryopreserving mammalian cells using highly toxic (at body temperature) cell-penetrating cryoprotectants requires multistep washing of the cryopreserved cells to remove the toxic cryoprotectant for further use, which is time-consuming and associated with significant cell loss (∼10% during each washing step). By contrast, the trehalose-cryopreserved cells can be used without washing, which should greatly facilitate the wide application of the burgeoning cell-based medicine

OVA66, a Tumor Associated Protein, Induces Oncogenic Transformation of NIH3T3 Cells

<div><p>The tumor associated antigen OVA66 has been demonstrated to be highly expressed in malignant tumors and implicated in various cellular processes. To further elucidate its oncogenic character, we established an OVA66 stably overexpressed NIH3T3 cell line and a vector transfected control, named NIH3T3-flagOVA66 and NIH3T3-mock, respectively. NIH3T3-flagOVA66 cells showed faster cell cycling, proliferation, cell migration and more resistance to 5-fluorouracil-induced apoptosis. When NIH3T3-flagOVA66 and NIH3T3-mock cells were injected into nude mice for xenograft tumorigenicity assays, the NIH3T3-flagOVA66 cells formed tumors whereas no tumors were observed in mice inoculated with NIH3T3-mock cells. Analysis of PI3K/AKT and ERK1/2 MAPK signaling pathways by serum stimulation indicated hyperactivation of AKT and ERK1/2 in NIH3T3-flagOVA66 cells compared with NIH3T3-mock cells, while a decreased level of p-AKT and p-ERK1/2 were observed in OVA66 knocked down HeLa cells. To further validate if the p-AKT or p-ERK1/2 is essential for OVA66 induced oncogenic transformation, we treated the cells with the PI3K/AKT specific inhibitor LY294002 and the ERK1/2 MAPK specific inhibitor PD98059 and found either inhibitor can attenuate the cell colony forming ability in soft agar and the cell viability of NIH3T3-flagOVA66 cells, suggesting aberrantly activated AKT and ERK1/2 signaling be indispensible of the tumorigenic role of OVA66. Our results indicate that OVA66 is important in oncogenic transformation, promoting proliferation, cell migration and reducing apoptosis via hyperactivating PI3K/AKT and ERK1/2 MAPK signaling pathway. Thus, OVA66 might be a novel target for early detection, prevention and treatment of tumors in the future.</p></div

NIH3T3-flagOVA66 cells showed a stably expression of OVA66 mRNA and protein.

<p>A. OVA66 mRNA level was examined by RT-PCR. Lane 1 and 2, OVA66 of NIH3T3-flagOVA66 and NIH3T3-mock; Lane 3 and 4, GAPDH of NIH3T3-flagOVA66 and NIH3T3-mock cells. B. Western blot analysis of flagOVA66 protein level in NIH3T3-flagOVA66 cells. C. Quantization of OVA66 protein by FACS analysis using intracellular staining. The thick blue line indicated the expression of OVA66 in NIH3T3-flagOVA66 cells.</p

AKT and ERK1/2 phosphorylation.

<p>A. Analysis of serum-stimulated phosphorylation of AKT and ERK1/2 as well as total AKT and ERK1/2 protein levels in NIH3T3-flagOVA66 and NIH3T3-mock cells pretreated with control vehicle DMSO, 10 μM LY294002 and 10 μM PD98059 were analyzed by western blotting using actin as a loading control. B. Detection of colony formation in soft agar seeded with NIH3T3-mock and NIH3T3-flagOVA66 cells treated with DMSO, 10 μM LY294002 and 10 μM PD98059. Magnification: 100×, the histogram shows quantification of cell colonies in soft agar. The data are represented as mean ± SEM (n = 3), *<i>P</i>≤0.05, **<i>P</i>≤0.01. C. 400 cells per well were seeded in a 6-well plate for 24 h, followed by treatment with DMSO, 10 μM LY294002 or 10 μM PD98059 for 10 days. Cells were then stained with crystal violet for imaging cell clones in plates. D. Representative wound healing assay images at 0 and 24 hours and the quantification of the relative scratch width after 24 h. Magnification: 100×. Data are mean ± SEM. **P≤0.01, ***P≤0.001. E. Cells of each group of the wound healing assay after 24 h were lysed and the total proteins were analyzed by western blotting.</p

Apoptosis assay.

<p>A. FACS analysis of apoptosis using Annexin-V/PI stains detected by BD Accuri C6 flow cytometer. B. Apoptotic cells at 24 h and 48 h after treatment with different concentrations of 5-FU were quantified. The data are represented as mean ± SEM (n = 3), *<i>P</i>≤0.05, **<i>P</i>≤0.01, ***<i>P</i>≤0.001.</p