An alginate-based macroporous hydrogel matrix to trap cancer cells.

To overcome the radioresistance of glioblastoma (GBM) cells infiltrated in the brain, we propose to attract these cancer cells into a trap to which a lethal radiation dose can be delivered safely. Herein, we have prepared and characterized a sodium alginate-based macroporous hydrogel as a potential cancer cell trap. Microcomputed X-ray tomography shows that the hydrogel matrices comprise interconnected pores with an average diameter of 300 µm. The F98 GBM cells migrated in the pores and mainly accumulated in the center of the matrix. Depending on the number of cancer cells added, the grafting of RGD cell-adhesion peptides to the alginate resulted in a 4 to 10 times increase in the number of F98 cells (which overexpress the associated αvß3 and αvß5 binding integrins) retained in the matrix. Finally, a radiation dose of 25 Gy eliminated all F98 cells trapped in the matrix, without significantly altering the matrix mechanical properties.

Effect and localization of phenanthrene in maize roots.

Polycyclic aromatic hydrocarbons (PAHs) have a toxic effect on plants, which limits the efficiency of phytomanagement of contaminated soils. The mechanisms underlying their toxicity are not fully understood. A cultivation experiment was carried out with maize, used as model plant, exposed to sand spiked with phenanthrene (50 or 150 mg kg(-1) dw). Epi-fluorescence microscopic observation of root sections was used to assess suberization of exodermis and endodermis and phenanthrene localization along the primary root length. For 10 days of cultivation, exodermis and endodermis suberization of exposed maize was more extensive. However, after 20 days of exposure, exodermis and endodermis of non-exposed roots were totally suberized, whilst PHE-exposed roots where less suberized. Early extensive suberization may act as barrier against PHE penetration, however longer exposure inhibits root maturation. Phenanthrene patches were located only near suberized exodermis and endodermis, which may therefore act as retention zones, where the hydrophobic phenanthrene accumulates during its radial transport.

Morphological and physiological responses of maize (Zea mays) exposed to sand contaminated by phenanthrene.

Phytoremediation is promising, but depends on clearly understanding contaminants' impact on plant functioning. We therefore focused on the impact of polycyclic aromatic hydrocarbons (PAH) on cultivated plants and understanding the impact of phenanthrene (PHE) on maize functioning (Zea mays). Cultivation was conducted under controlled conditions on artificially contaminated sand with PHE levels increasing from 50 to 750 mg PHE kg(-1). After four weeks, plants exposed to levels above 50 mg PHE kg(-1) presented decreased biomasses and reduced photosynthetic activity. These modifications were associated with higher biomass allocations to roots and lower ones to stems. The leaf biomass proportion was similar, with thinner blades than controls. PHE-exposed plant showed modified root architecture, with fewer roots of 0.2 and 0.4 mm in diameter. Leaves were potassium-deplete, but calcium, phosphorus, magnesium and zinc-enriched. Their content in nitrogen, iron, sulfur and manganese was unaffected. These responses resembled those of water-stress, although water contents in plant organs were not affected by PHE and water supply was not limited. They also indicated a possible perturbation of both nutritional functioning and photosynthesis.