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1.
Front Plant Sci ; 9: 1069, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30105040

RESUMO

Climate warming poses considerable challenges for alpine plant species, especially for competitively inferior ones with resource-conservative adaptations to cold climates. The Himalayas are warming at rates considerably faster than the global average, so it is particularly important to assess how and through which mechanisms alpine plant species are affected there. We employed a demographic approach in a climate change experiment, where vegetation turfs were transplanted reciprocally between the central parts of the study species' (Viola biflora L. var. rockiana) range and the warmer range margin, with a temperature difference of ca. 1°C. In addition, turfs were also transplanted outside the range to warmer habitats, simulating two different scenarios of climate warming, +1 and +4°C. Transplanting to warmer sites negatively impacted population growth rates (λ), survival and clonality, but did not affect growth and fecundity, while the productivity of the plant community increased. The reciprocal transplants to the colder habitat showed the opposite effects, for both V. biflora and the plant community, indicating plastic responses of the study species, driven by changes in plant-plant competition. However, the leaf traits underlying the modeled population growth rates were origin-site specific and not affected by the climate-change treatments over the study period, suggesting local adaptation of growth form to competition in the warmer range margin, and to climate adversity in the colder range center. The transplants outside the present species' range showed consistently stronger reductions in population growth rate and survival, with mortality of 90-100% in the +4°C treatment. This illustrates that climatic changes beyond species' present climatic ranges pose a serious risk for range contraction and extinction for Himalayan alpine species in the near future. As V. biflora seems mostly limited by competition under warming, its persistence in a future climate may become increasingly dependent on keeping competitive effects from the surrounding community low, for instance by management interventions like grazing and mowing.

2.
ACS Appl Mater Interfaces ; 10(23): 19545-19553, 2018 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-29770688

RESUMO

Developing low-cost and highly efficient nanobiochips are important for liquid biopsies, real-time monitoring, and precision medicine. By in situ growth of silica nanowires on a commercial frosted slide, we develop a biochip for effective circulating tumor cells (CTCs) detection after modifying epithelial cell adhesion molecule antibody (anti-EpCAM). The biochip shows the specificity and high capture efficiency of 85.4 ± 8.3% for prostate cancer cell line (PC-3). The microsized frosted slides and silica nanowires allow enhanced efficiency in capture EpCAM positive cells by synergistic topographic interactions. And the capture efficiency of biochip increased with the increase of silica nanowires length on frosted slide. The biochip shows that micro/nanocomposite structures improve the capture efficiency of PC-3 more than 70% toward plain slide. Furthermore, the nanobiochip has been successfully applied to identify CTCs from whole blood specimens of prostate cancer patients. Thus, this frosted slide-based biochip may provide a cheap and effective way of clinical monitoring of CTCs.


Assuntos
Nanofios , Antígenos de Neoplasias , Moléculas de Adesão Celular , Linhagem Celular Tumoral , Molécula de Adesão da Célula Epitelial , Humanos , Masculino , Células Neoplásicas Circulantes , Neoplasias da Próstata , Dióxido de Silício
3.
Chemphyschem ; 19(16): 2046-2051, 2018 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-29573096

RESUMO

Highly efficient cell capture and release with low background are urgently required for early diagnosis of diseases such as cancer. Herein, we report an electrochemical responsive superhydrophilic surface exhibiting specific cell capture and release with high yields and extremely low nonspecific adhesion. Through electrochemical deposition, 3-substituted thiophene derivatives are deposited onto indium tin oxide (ITO) nanowire arrays with 4-n-nonylbenzeneboronic acid (BA) as dopant, fabricating the electrochemical responsive superhydrophilic surfaces. The molecular recognition between sialic acids over-expressed on the cell membrane and doped BAs endows the electrochemical responsive surfaces with the ability to capture and release targeted cancer cells. By adjusting the substituent group of thiophene derivatives, the surface wettability can be readily regulated and further utilized for reducing nonspecific cell adhesion. Significantly, the released cells still maintain a high proliferation ability, which indicates that the applied potential does not significantly harm the cells. Therefore, these results may provide a new strategy to achieve advanced functions of biomedical materials, such as low nonspecific adhesion.

4.
Chemphyschem ; 19(16): 2107-2112, 2018 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-29543403

RESUMO

To overcome the low efficiency of single-responsive smart surfaces, we have constructed a dual-responsive smart surface - poly(spiropyran-co-N-isopropylacrylamide) (poly(SP-co-NiPAAm))-grafted silicon nanowire arrays - by combining photo-responsive SP and thermo-responsive NiPAAm units for enhancing the efficiencies of cancer-cell capture and release. These enhanced efficiencies probably originate from the binary cooperative effect of two responsive building units: NiPAAm units can decrease the steric hindrance between SP units during the isomerization while SP units can facilitate phase transition of NiPAAm units. This study provides a new strategy for designing smart materials and surfaces with efficient responsiveness for biomedical applications.

5.
Adv Healthc Mater ; 6(15)2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28471542

RESUMO

The efficient recognition and isolation of rare cancer cells holds great promise for cancer diagnosis and prognosis. In nature, pollens exploit spiky structures to realize recognition and adhesion to stigma. Herein, a bioinspired pollen-like hierarchical surface is developed by replicating the assembly of pollen grains, and efficient and specific recognition to target cancer cells is achieved. The pollen-like surface is fabricated by combining filtering-assisted assembly and soft lithography-based replication of pollen grains of wild chrysanthemum. After modification with a capture agent specific to cancer cells, the pollen-like surface enables the capture of target cancer cells with high efficiency and specificity. In addition, the pollen-like surface not only assures high viability of captured cells but also performs well in cell mixture system and at low cell density. This study represents a good example of constructing cell recognition biointerfaces inspired by pollen-stigma adhesion.


Assuntos
Materiais Biomiméticos/química , Adesão Celular , Separação Celular/métodos , Neoplasias Experimentais/patologia , Neoplasias Experimentais/fisiopatologia , Pólen/química , Pólen/ultraestrutura , Linhagem Celular Tumoral , Humanos , Teste de Materiais , Propriedades de Superfície
6.
ACS Appl Mater Interfaces ; 9(12): 10537-10543, 2017 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-28262015

RESUMO

Cell-surface topographic interactions can direct the design of biointerfaces, which have been widely used in isolation of circulating tumor cells or fundamental cell biological research. By using three kinds of cancer cell-replicated surfaces with differentiated structures, we uncover that multiscale-cooperative topographic interactions (at both nanoscale and microscale) coupled with molecular recognition enable efficient and specific isolation of cancer cells. The cell replicas precisely inherit the structural features from the original cancer cells, providing not only preferable structures for matching with cancer cells but also a unique platform to interrogate whether certain cancer cells can optimally match with their own replicated surfaces. The results reveal that cancer cells do not show preferential recognitions to their respective replicas, while the capture agent-modified surfaces with hierarchical structures exhibit improved cancer cell capture efficiencies. Two levels of topographic interactions between cancer cells and cell replica surfaces exist. Nanoscale filopodia on cancer cells can topographically interact with different nanostructures on replica surfaces. In addition, microscale concave/convex on surfaces provide suitable sites for trapping cancer cells. This study may promote smart design of multiscale biofunctional materials that can specifically recognize cancer cells.


Assuntos
Neoplasias , Humanos , Nanoestruturas , Células Neoplásicas Circulantes , Propriedades de Superfície
7.
Chem Commun (Camb) ; 51(32): 6968-71, 2015 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-25797486

RESUMO

A new class of locked-flavylium fluorophores with tunable emission wavelengths based on intramolecular charge transfer were designed, synthesized, and evaluated. The optical studies indicate that sensor LF3 can display an intriguing character, fluorescence ratiometric response in three channels by tuning the ICT efficiencies.


Assuntos
Benzopiranos/química , Corantes Fluorescentes/química , Imagem Óptica/métodos , Cor , Transporte de Elétrons , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Espectrometria de Fluorescência
8.
Chemistry ; 21(2): 733-45, 2015 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-25388080

RESUMO

The development of near-infrared (NIR) functional fluorescent dyes has gained increasing attention over the last few decades. Herein, we describe the development of a unique type of xanthene-cyanine fused NIR fluorophores, XC dyes, formed by reacting chloro-substituted cyanine with resorcin or its analogues under anhydrous conditions. XC dyes are a hybrid of cyanine and xanthene. The preliminary mechanistic studies indicate that the formation of XC compounds likely includes a sequence of cyclization and oxidation. XC dyes have absorption and emission in the NIR region, and their fluorescence properties can be controlled by modifications of the key hydroxyl and amine groups. The novel XC NIR dyes are advantageous over previously developed merocyanine dyes NIR dyes in their chemical stability against strong nucleophiles. Quantum chemical calculations reveal that the distinct properties of XC and HD dyes can be attributed to their structural differences. By taking advantage of the superior properties of XC dyes, we have further constructed a new NIR fluorescent probe, XC-H2 S, which is capable of monitoring both the concentration- and time-dependent variations of H2 S in living animals, highlighting the value of XC NIR dyes. We expect that the unique XC NIR dyes developed herein will find broader applications than HD NIR dyes as fluorescent platforms for the development of a wide variety of NIR fluorescent probes, in particular, those suitable for targets of interest that have strong nucleophilic character.


Assuntos
Carbocianinas/química , Corantes Fluorescentes/química , Sulfeto de Hidrogênio/análise , Xantenos/química , Animais , Carbocianinas/síntese química , Corantes Fluorescentes/síntese química , Raios Infravermelhos , Camundongos , Modelos Moleculares , Imagem Óptica , Fotólise , Xantenos/síntese química
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