Microfluidic device for multimodal characterization of pancreatic islets

Abstract

A microfluidic device to perfuse pancreatic islets while simultaneously characterizing their functionality through fluorescence imaging of the mitochondrial membrane potential and intracellular calcium ([Ca2+]i) in addition to enzyme linked immunosorbent assay (ELISA) quantification of secreted insulin was developed and characterized. This multimodal characterization of islet function will facilitate rapid assessment of tissue quality immediately following isolation from donor pancreas and allow more informed transplantation decisions to be made which may improve transplantation outcomes. The microfluidic perfusion chamber allows flow rates of up to 1 mL/min, without any noticeable perturbation or shear of islets. This multimodal quantification was done on both mouse and human islets. The ability of this simple microfluidic device to detect subtle variations in islet responses in different functional assays performed in short time-periods demonstrates that the microfluidic perfusion chamber device can be used as a new gold standard to perform comprehensive islet analysis and obtain a more meaningful predictive value for islet functionality prior to transplantation into recipients, which is currently difficult to predict using a single functional assay.

Functional MRI characterization of isolated human islet activation

“…Their significance still needs to be related to in vivo performance, and they can only provide an average assessment of islet preparation. Recently, a very interesting microfluidic device has been described which allows for the integration of different biochemical assays and optical imaging of the isolated islets (21). Although this is an exciting device, it is limited to in vitro applications.…”

Microfluidic platform for assessing pancreatic islet functionality through dielectric spectroscopy

“…In addition, microfluidic platforms can allow realtime measurements of islet secretion through continuous sampling of the islet effluent. 9 In terms of quantitative measurement, enzyme-linked immunosorbent assay (ELISA) and western blots are common standard techniques for quantification of insulin secretion, providing preliminary assessments of functionality. Although mature and specific, these techniques lack dynamic assessment, are costly and time-consuming, and they involve multistep protocols that often result in error.…”

“…16 The method of islet immobilization on different microfluidic platforms varies, including use of mechanical actuators 15 and well arrays. 9,17 Using actuators requires complicated islet loading procedures, prevents good perifusion around the islets, and subjects islets to mechanical stress. Well-type arrays enable immobilization of a small but sufficient quantity of islets for batch analysis of islet preparations.…”

Sensing and Sensibility: Single‐Islet‐based Quality Control Assay of Cryopreserved Pancreatic Islets with Functionalized Hydrogel Microcapsules

“…[ 8 ] Ability to reverse diabetes mellitus after islet infusion to diabetic nude mice has been used as the in vivo model to evaluate the islet potency, but the investigation can last for up to 45 d, which signifi cantly hinders the wide application of this method. [ 9 ] Thus far, assessing the mitochondrial functions, particularly measuring the oxygen consumption rate (OCR) of islets, appears to be the most promising assay, which correlates well with the transplant outcomes in the nude mice bioassay. [ 7 ] OCR provides an important readout to probe the islet viability and functionality because it refl ects multiple functional processes in pancreatic islets, which are associated with the insulin secretion, oxidative stress, and the viability of islets.…”