Metal-organic framework templated electrodeposition of functional gold nanostructures

Utilizing a pair of quick, scalable electrochemical processes, the permanently porous MOF HKUST-1 was electrochemically grown on a copper electrode and this HKUST-1-coated electrode was used to template electrodeposition of a gold nanostructure within the pore network of the MOF. Transmission electron microscopy demonstrates that a proportion of the gold nanostructures exhibit structural features replicating the pore space of this ∼1.4 nm maximum pore diameter MOF, as well as regions that are larger in size. Scanning electron microscopy shows that the electrodeposited gold nanostructure, produced under certain conditions of synthesis and template removal, is sufficiently inter-grown and mechanically robust to retain the octahedral morphology of the HKUST-1 template crystals. The functionality of the gold nanostructure within the crystalline HKUST-1 was demonstrated through the surface enhanced Raman spectroscopic (SERS) detection of 4-fluorothiophenol at concentrations as low as 1 μM. The reported process is confirmed as a viable electrodeposition method for obtaining functional, accessible metal nanostructures encapsulated within MOF crystals

Laser microstructuration of three-dimensional enzyme reactors in microfluidic channels

International audienceIn this paper, we report on the fabrication of three-dimensional (3D) enzymatic microreactors within polydimethylsiloxane microfluidic channels through a photocrosslinking mechanism mediated by the two-photon absorption process at the focal point of pulse lasers, i.e., a sub-nanosecond Nd:YAG microlaser or a femtosecond Ti:Sapphire laser. This approach allows the building of localized 3D trypsin structures with submicron resolution. The fabrication of two different trypsin structures was successfully demonstrated using Eosin Y and Flavin Adenine Dinucleotide as biological photosensitizers: (i) arrays of 3D cylindrical rows and (ii) 3D woodpile structure. The enzymatic activity of the fabricated structures was evaluated by fluorescence spectroscopy using BODIPY FL casein as fluorogenic substrate. The real time investigation of the peptide cleavage into the microfluidic channel demonstrated that the fabricated trypsin microstructures maintain their catalytic activity. This approach opens up the way to complex multistep enzymatic reactions in well-localized regions of microfluidic devices, with great importance in health screening and biomedical diagnostics

Microstructuration of protein matrices by laser-induced photochemistry

International audienceWe report on the laser fabrication of BSA and type I collagen microstructures using Eosin Y or Rose Bengal photo sensitizers. Similar cross-linking results have been obtained by one-photon absorption or two-photon absorption using a green Q-switched microlaser or a near-infrared mode-locked Ti:sapphire laser, respectively. The microstructure resolution depends on the laser power, but is typically limited by the size of the laser beam within the sample. The cross-linking of type I collagen with Rose Bengal is obtained in acidic conditions with a large photosensitizer concentration in the millimole range. The biocompatibility of microstructures was demonstrated by observing the specific adhesion of cells on collagen lines

"Advances in Two-Photon Microstructuration of Polymers, Proteins and Metallic Materials with Q-switched Microlasers"

International audienc

"Advances in Two-Photon Microstructuration of Polymers, Proteins and Metallic Materials with Q-switched Microlasers"

International audienc