Local detection of mechanically induced ATP release from bone cells with ATP microbiosensors

Pyrophosphate: a key inhibitor of mineralisation

“…connexin hemichannels, the P2X7 receptor) but the predominant mechanism appears to be vesicular exocytosis (see review [21]). The extent of cellular ATP release can also be influenced by external stimuli such as hypoxia [22,23], mechanical stress [24,25] and vitamin D [26]. Since ATP hydrolysis is a key source of extracellular pyrophosphate, factors which regulate ATP release may also indirectly affect pyrophosphate levels and thus the local rates of mineralisation.…”

The role of purinergic signalling in the musculoskeletal system

“…The amount of ATP released from osteoblasts depends on their differentiation state, with mature, bone-forming cells releasing up to seven-fold more than immature, proliferating cells (Orriss et al, 2009). Several studies have demonstrated enhanced ATP release in response to different external stimuli including hypoxia (Orriss et al, 2009), mechanical stress (Hecht et al, 2013), fluid flow (Genetos et al, 2005;Romanello et al, 2005), vitamin D (Biswas et al, 2009) and ultrasound (Alvarenga et al, 2010;Hayton et al, 2005). A recent investigation examined the effect of different forms of mechanical stimulation on ATP release from human osteoblast-like SaOS-2 cells, including turbulent fluid flow, laminar fluid flow, substrate strain and 3D compressive loading (Rumney et al, 2012).…”

Poly(benzoxazine) as an Immobilization Matrix for Miniaturized ATP and Glucose Biosensors

“…The calibration curves show two different slopes over the tested concentration range, which may be explained by the change of the immobilization matrix and hence, the diffusion behavior of the analytes due to a local pH change associated to the enzymatic catalyzed reactions. The obtained linear range of 4–14.8 mM for glucose and 0.3–8 μM for ATP (largest slope) is significantly reduced in comparison to microbiosensors using e. g. Canguard – an electrophoretic paint – as entrapment matrix, which resulted in a linear range up to 40 μM ATP but only with sensitivities of 1–5 pA/μM ATP . However, it has to be noted that besides the lower sensitivity such electrodeposition paints also yield high‐volume deposits with polymer heights up to several micrometers, exhibiting a significantly reduced mechanical stability.…”

“…This allowed in combination with scanning electrochemical microscopy (SECM) precise positioning of the biosensor for localized imaging of ATP diffusion through biomimetic pores . The same approach was applied in a stationary mode for recording the release of ATP induced by mechanical stimulation in close proximity to MC3T3‐E1 cells . A competitive assay was also shown using pyrroloquinoline quinone‐dependent glucose dehydrogenase instead of glucose oxidase with the advantage that only a potential of 100 mV vs. Ag/AgCl reference electrode was required, which limits the co‐oxidation of interfering compounds, however, requires the addition of a redox mediator .…”