Ionophore-Based Potassium Selective Fluorescent Organosilica Nano-Optodes Containing Covalently Attached Solvatochromic Dyes

Fluorescent nanoprobes containing ionophores and solvatochromic dyes (SDs) were previously reported as an alternative to chromoionophore-based nano-optodes. However, the small-molecular SDs are prone to leakage and sequestration in complex samples. Here, we chemically attached the SDs to the surface of organosilica nanospheres through copper-catalyzed Click chemistry to prevent dye leakage. The nano-optodes remained well responsive to K+ even after exposure to a large amount of cation-exchange resin, which acted as a sink of the SDs. The potassium nanoprobes exhibited a dynamic range between 1 μM to 10 mM and a good selectivity thanks to valinomycin. Preliminary sensing device based on a nylon filter paper and agarose hydrogel was demonstrated. The results indicate that the covalent anchoring of SDs on nanospheres is promising for developing ionophore-based nanoprobes.

Effectiveness of Cultured Chondrocytes in the Restoration of Bone and Cartilage Defects of the Knee Joint (Experimental Study)

Summary. The aim of our study was to determine the effectiveness of cultured articular chondrocytes in agarose hydrogel (early follow-up, 3 months) in the restoration of simulated cartilaginous defects of the knee of critical size in large animals. Materials and Methods. The experimental series consisted of 4 dogs (right hind limb) with created defects of articular cartilage deeper than the subchondral bone in the area of the intercondylar notch of the femur with a diameter of 3 mm and 5 mm deep. At the second stage of the experiment, agarose hydrogel with cultured allogeneic chondrocytes was implanted (sealed) into the injured joint intraarticularly. The control series consisted of 4 animals (left hind limb) without agarose hydrogel with cultured allogeneic chondrocytes implantation to the intercondylar notch of the femur. Agarose hydrogel with cultured allogeneic chondrocytes was implanted by application into the defects of the articular surfaces after curettage of the bottom and walls of bone and cartilage defects of the articular surfaces. Cell preparations and cultures were microscopically magnified at 40, 100, 200, and 320 times. Histological sections 10-15 μm thick, made using a cryotome, were stained with hematoxylin-eosin and hematoxylin-picrofuxin according to van Gizon. Results. The technique of enzymatic isolation of chondrocytes articular cartilage of a dog was optimized. The satisfactory efficacy of cultured allogeneic articular chondrocytes in agarose hydrogel (early observation) in the treatment of simulated bone and cartilage defects of critical size in large animals within the planned observation period is shown. Conclusions. The experimental study explored the effectiveness of the use of cultured allogenic articular chondrocytes embedded in agarose hydrogel (early follow-up period) in the restoration of modeled knee cartilage defects of critical size in dogs within the planned follow-up period. For the selected follow-up period (3 months), the signs of regenerate formation, which was characterized by its immaturity and the presence of a mixture of fibrous connective tissue and fibrous cartilage with the chondroid structure inclusions, were revealed in experimental group.