Upconversion Nanoparticles Intercalated in Large Polymer Micelles for Tumor Imaging and Chemo/Photothermal Therapy.

Frontiers in theranostics are driving the demand for multifunctional nanoagents. Upconversion nanoparticle (UCNP)-based systems activated by near-infrared (NIR) light deeply penetrating biotissue are a powerful tool for the simultaneous diagnosis and therapy of cancer. The intercalation into large polymer micelles of poly(maleic anhydride-alt-1-octadecene) provided the creation of biocompatible UCNPs. The intrinsic properties of UCNPs (core@shell structure NaYF4:Yb3+/Tm3+@NaYF4) embedded in micelles delivered NIR-to-NIR visualization, photothermal therapy, and high drug capacity. Further surface modification of micelles with a thermosensitive polymer (poly-N-vinylcaprolactam) exhibiting a conformation transition provided gradual drug (doxorubicin) release. In addition, the decoration of UCNP micelles with Ag nanoparticles (Ag NPs) synthesized in situ by silver ion reduction enhanced the cytotoxicity of micelles at cell growth temperature. Cell viability assessment on Sk-Br-3, MDA-MB-231, and WI-26 cell lines confirmed this effect. The efficiency of the prepared UCNP complex was evaluated in vivo by Sk-Br-3 xenograft regression in mice for 25 days after peritumoral injection and photoactivation of the lesions with NIR light. The designed polymer micelles hold promise as a photoactivated theranostic agent with quattro-functionalities (NIR absorption, photothermal effect, Ag NP cytotoxicity, and Dox loading) that provides imaging along with chemo- and photothermal therapy enhanced with Ag NPs.

Theoretical and Experimental Assay of Shock Experienced by Yeast Cells during Laser Bioprinting.

Laser-induced forward transfer (LIFT) is a useful technique for bioprinting using gel-embedded cells. However, little is known about the stresses experienced by cells during LIFT. This paper theoretically and experimentally explores the levels of laser pulse irradiation and pulsed heating experienced by yeast cells during LIFT. It has been found that only 5% of the cells in the gel layer adjacent to the absorbing Ti film should be significantly heated for fractions of microseconds, which was confirmed by the fact that a corresponding population of cells died during LIFT. This was accompanied by the near-complete dimming of intracellular green fluorescent protein, also observed in response to heat shock. It is shown that microorganisms in the gel layer experience laser irradiation with an energy density of ~0.1-6 J/cm2. This level of irradiation had no effect on yeast on its own. We conclude that in a wide range of laser fluences, bioprinting kills only a minority of the cell population. Importantly, we detected a previously unobserved change in membrane permeability in viable cells. Our data provide a wider perspective on the effects of LIFT-based bioprinting on living organisms and might provide new uses for the procedure based on its effects on cell permeability.

Tepidiforma bonchosmolovskayae gen. nov., sp. nov., a moderately thermophilic Chloroflexi bacterium from a Chukotka hot spring (Arctic, Russia), representing a novel class, Tepidiformia, which includes the previously uncultivated lineage OLB14.

A novel aerobic moderately thermophilic bacterium, strain 3753OT, was isolated from a Chukotka hot spring (Arctic, Russia) using the newly developed technology of laser engineering of microbial systems. Сells were regular short rods, 0.4×0.8-2.0 µm in size, with a monoderm-type envelope and a single flagellum. The temperature and pH ranges for growth were 42-60 °C and pH 6.5-8.5, the optima being 50-54 °C and pH 7.3. Strain 3753OT grew chemoorganoheterotrophically on a number of carbohydrates or peptidic substrates and volatile fatty acids, and chemolithoautotrophically with siderite (FeCO3) as the electron donor. The major cellular fatty acid was branched C19 : 0. Phosphatidylethanolamine, phosphatidylglycerol and two unidentified phospholipids as well as two yellow carotenoid-type pigments were detected in the polar lipid extract. Strain 3753OT was inhibited by chloramphenicol, polymyxin B, vancomycin, streptomycin, neomycin and kanamycin, but resistant to the action of novobiocin and ampicillin. The DNA G+C content was 69.9 mol%. The 16S rRNA gene as well as 51 conservative protein sequence-based phylogenetic analyses placed strain 3753OT within the previously uncultivated lineage OLB14 in the phylum Chloroflexi. Taking into account the phylogenetic position as well as phenotypic properties of the novel isolate, the novel genus and species Tepidiforma bonchosmolovskayae gen. nov., sp. nov., within the Tepidiformaceae fam. nov., the Tepidiformales ord. nov. and the Tepidiformia classis nov. are proposed. The type strain of Tepidiforma bonchosmolovskayae is 3753OT (=VKM B-3389T=KTCT 72284T).