Assessment of a Silicon-Photomultiplier-Based Platform for the Measurement of Intracellular Calcium Dynamics with Targeted Aequorin

Abstract

Ca 2+ is among the most important intracellular second messengers participating in a plethora of biological processes, and the measurement of Ca 2+ fluctuations is significant in the phenomenology of the underlying processes. Aequorin-based Ca 2+ probes represent an invaluable tool for reliable measurement of Ca 2+ concentrations and dynamics in different subcellular compartments. However, their use is limited due to the lack on the market of ready-to-use, cost-effective, and portable devices for the detection and readout of the low-intensity bioluminescence signal produced by these probes. Silicon photomultipliers (SiPMs) are rapidly evolving solid-state sensors for low light detection, with single photon sensitivity and photon number resolving capability, featuring low cost, low voltage, and compact format. Thus, they may represent the sensors of choice for the development of such devices and, more in general, of a new generation of multipurpose bioluminescence detectors suitable for cell biology studies. Ideally, a detector customized for these purposes must combine high dynamic range with high fidelity in reconstructing the light intensity signal temporal profile. In this article, the ability to perform aequorin-based intracellular Ca 2+ measurements using a multipurpose, low-cost setup exploiting SiPMs as the sensors is demonstrated. SiPMs turn out to assure performances comparable to those exhibited by a custom-designed photomultiplier tube-based aequorinometer. Moreover, the flexibility of SiPM-based devices might pave the way toward routinely and wide scale application of innovative biophysical protocols.

Ultrasensitive On-Field Luminescence Detection Using a Low-Cost Silicon Photomultiplier Device

“…Silicon photomultipliers (SiPMs) have also been proposed as sensitive light detectors for BL. , SiPMs are arrays of avalanche photodetectors working in Geiger mode (GM-APDs), each one having integrated passive-quenching resistor and connected in parallel . Due to their high quantum efficiency, low energy and bias voltage requirements, and rapid fast response time (in nanosecond time scale), SiPMs have attracted significant interest for various applications, providing in some cases better performance than smartphones. − Despite jeopardized efforts, there is no clear evidence about the selection of the most suitable light detector for implementation into portable devices and scaled-up deployments. This choice in fact should consider not only the sensitivity but also the cost, ruggedness, and ease of integration.…”

Signaling Pathway Governed by Lipid Derived Molecules as Secondary Messenger

“…al., 2020). Information is encoded in the amplitude, spike length, and frequency of repetitive oscillating Ca 2+ spikes (Ruffinatti et. al., 2020).…”

Portable light detectors for bioluminescence biosensing applications: A comprehensive review from the analytical chemist's perspective

“…Very recently these solid-state sensors were also exploited in a low-cost customized set up for performing aequorin-based intracellular Ca 2+ measurements [64]. This system showed performance When applied to spiked food samples, i.e.…”