To facilitate deciphering the information content in the glycome, thin film-coated photoactivatable surfaces were applied for covalent immobilization of glycans, glycoconjugates, or lectins in microarray formats. Light-induced immobilization of a series of bacterial exopolysaccharides on photoactivatable dextran-coated analytical platforms allowed covalent binding of the exopolysaccharides. Their specific galactose decoration was detected with fluorescence-labeled lectins. Similarly, glycoconjugates were covalently immobilized and displayed glycans were profiled for fucose, sialic acid, galactose, and lactosamine epitopes. The applicability of such platforms for glycan profiling was further tested with extracts of Caco2 epithelial cells. Following spontaneous differentiation or on pretreatment with sialyllactose, Caco2 cells showed a reduction of specific glycan epitopes. The changed glycosylation phenotypes coincided with altered enteropathogenic E. coli adhesion to the cells. This microarray strategy was also suitable for the immobilization of lectins through biotin-neutravidin-biotin bridging on platforms functionalized with a biotin derivatized photoactivatable dextran. All immobilized glycans were specifically and differentially detected either on glycoconjugate or lectin arrays. The results demonstrate the feasibility and versatility of the novel platforms for glycan profiling.

Continuous health monitoring often requires hospitalization, which can become an expensive and inconvenient choice for the patient. In this perspective, wearable sensors that allow in situ biosensing constitute a very promising technology. This work aims to develop immunosensors for continuous monitoring of the wound healing process, based on pH changes, as well as on the concentrations of inflammatory proteins such as the C-reactive protein (CRP). Sensing principles include the use of responsive hydrogels that swell in response to changes in the surroundings, and the use of functional surfaces that specifically recognize the target protein. The detection principle is based on an optical signal, using the evanescent field of light propagating along a waveguide, probing refractive index changes. An optical sensing system that can be integrated in a wound dressing patch has been designed, including a white light source (LED), and a spectrometer for detection. The sensor was successfully tested in the laboratory with biological samples (blood serum), demonstrating reversible pH measurements between pH 6-8, and detection of changes in the concentration of CRP between 1 and 100 μg/ml. The sensor will later be integrated into wound dressings or bandages, forming a sensing patch that is connected via optical fibres and electrical wires to the detection system and power supply. This novel technology will be particularly valuable in applications such as the supervision of skin grafts and ulcer treatments.

ABSTRACT:The present report describes two series of new porphyrazine macrocycles derived from tetrakis(selenodiazole)porphyrazine, TSeDPzH 2 , having the formulae [TSeDPzM]obtained by reaction of the free ligand with the appropriate metal acetate in dimethyl (DMSO), and, respectively, pyridine. All the species isolated are stable-to-air substantially amorphous materials, almost completely insoluble in the usual organic solvents and N-donors (pyridine etc.), and only slightly soluble in CF 3 COOH or 96% H 2 SO 4 . The complexes have been investigated by IR, Raman, and UV-vis spectra, and magnetic susceptibility measurements. Their properties in terms of electronic structure and reactivity towards N-bases are discussed in comparison with their S-containing analogs and the class of the structurally similar metal phthalocyanines.

Nanoparticles (NPs) are being used or explored for the development of biomedical applications in diagnosis and therapy, including imaging and drug delivery. Therefore, reliable tools are needed to study the behavior of NPs in biological environment, in particular the transport of NPs across biological barriers, including the blood-brain tumor barrier (BBTB), a challenging question. Previous studies have addressed the translocation of NPs of various compositions across cell layers, mostly using only one type of cells. Using a coculture model of the human BBTB, consisting in human cerebral endothelial cells preloaded with ultrasmall superparamagnetic iron oxide nanoparticles (USPIO NPs) and unloaded human glioblastoma cells grown on each side of newly developed ultrathin permeable silicon nitride supports as a model of the human BBTB, we demonstrate for the first time the transfer of USPIO NPs from human brain-derived endothelial cells to glioblastoma cells. The reduced thickness of the permeable mechanical support compares better than commercially available polymeric supports to the thickness of the basement membrane of the cerebral vascular system. These results are the first report supporting the possibility that USPIO NPs could be directly transferred from endothelial cells to glioblastoma cells across a BBTB. Thus, the use of such ultrathin porous supports provides a new in vitro approach to study the delivery of nanotherapeutics to brain cancers. Our results also suggest a novel possibility for nanoparticles to deliver therapeutics to the brain using endothelial to neural cells transfer.

This article describes the morphological and chemical characterization of stimuli-responsive functionalized silicon surfaces provided in parallel by atomic force spectroscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) enhanced by the single-beam sample reference attenuated total reflection method (SBSR-ATR). The stimuli-responsive behavior of the surfaces was obtained by grafting-to in melt carboxyl-terminated poly-N-isopropylacryl amides (PNIPAAM) with different degree of polymerization (DP) on epoxide-functionalized silicon substrates. The unprecedented real time and in situ physicochemical insight into the temperature-triggered response of the densely packed superficial brushes allowed for the selection of a PNIPAAM with a specific DP as a suitable polymer for the fabrication of silicon membranes exhibiting switchable nanopores. The fabrication process combines the manufacture of nanoporous silicon surfaces and their subsequent chemical functionalization by the grafting-to in melt of the selected polymer. Then, relevant information was obtained in what concerns the chemical modifications behind the topographical changes that drive the functioning of PNIPAAM-based hybrid nanovalves as well as the timescale on which the opening and closing of the nanopores occur.