ABSTRACT
Phytase is the commercial enzyme for bioconversion of phytate substrate to digestible phosphate ions. Recently silver nanoclusters (AgNCs) have received great attention as the optical transducer nanoparticles in biosensors structure. The novel detection platform was developed to detect the phytase enzyme activity and phosphate ions based on fluorescence quenching of AgNCs. The AgNCs were synthesized through gelatin supported reaction and characterized by TEM, FTIR and XRD analysis. The hydrolytic effect of phytase enzyme and subsequent phosphate release led to suppression of AgNCs fluorescence. The linear range was observed for enzyme in the range of 0.5-5 U/mL with the detection limit of 0.2 U/mL. Also, the same fluorescence quenching effect was observed in the presence of phosphate ion in the linear range of 1 to 16 µM with a detection limit of 0.5 µM. The proposed mechanism showed effectiveness of detection strategy for detection of phytase enzyme and phosphate ion.
Subject(s)
6-Phytase , Biosensing Techniques , Metal Nanoparticles , Gelatin , Ions , Limit of Detection , Metal Nanoparticles/chemistry , Phosphates , Silver/chemistry , Spectrometry, FluorescenceABSTRACT
Anisotropic, gecko-inspired, microstructured adhesives are one of the most promising solutions for many applications in robotics and biomedical applications that require controllable adhesives to grip flat surfaces. In such adhesives, normal adhesion is negligible when loaded solely in the normal direction, but becomes available when the adhesive is loaded in shear first. However, much remains to be learned regarding the friction and failure mechanisms of microstructures loaded in shear. In response, we analysed the load-displacement profiles of wedge-shaped microstructured adhesives comprised of nine different silicone elastomers and their mixtures loaded in shear. The results show that the friction profile depends on at least three factors related to material properties: interfacial adhesion strength in the normal direction (work of separation), elastic modulus and the sample's imperfections (e.g. contamination, misalignment and moulding errors). Moreover, the work of separation influences the maximum friction load such that for materials with the same elastic modulus, the strongest interfacial adhesion yields the lowest friction force. To explain this, we suggest that strongly adhering materials will lead to a macroscopic frictional sliding of the array rather than previously reported stick-slip behaviour.
