Fluidic devices with bead well geometries with spatially separated bead retention and signal detection segments and related methods

An analysis system comprising:

• a controller;
• an image processor;
• a detector in communication with the image processor;
• a microfluidic device comprising a plurality of reaction wells, each comprising a single bead retention segment and at least one signal detection segment in fluid communication with and spatially separated from the single bead retention segment,
• (i) wherein the at least one signal detection segment comprises an elongate channel that extends along a length direction and has a width that extends in a direction perpendicular to the length direction, wherein the width is less than a width of an adjacent single bead retention segment and less than a diameter of a single bead,
• (ii) wherein centerlines of single bead retention segments of neighboring reaction wells are spaced apart a distance of between 1 μm and 1 mm,
• (iii) wherein at least one of the at least one signal detection segment has an end portion that resides a distance of between 0.3× to 200× of a diameter of a single bead, from one or more of the single bead retention segments,
• (iv) wherein the width of the elongate channel is 25%-75% less than the width of the adjacent single bead retention segment,
• (v) wherein the reaction wells are provided in a density in a range of about 6,000 wells/cm2 to about 2,000,000 wells/cm2,
• (vi) wherein each of the plurality of reaction wells has a volumetric capacity in a range of 1 aL to 1 μL, and
• (vii) wherein the microfluidic device comprises a sealing agent that seals the reaction wells from each other such that the plurality of reaction wells are in fluid isolation from each other;
• and
• a plurality of single beads, wherein the single beads are magnetic beads,
• wherein the image processor is configured to identify parallel and spaced apart optical signals corresponding to different respective signal detection segments of the plurality of reaction wells of the microfluidic device while the single beads are held in the corresponding single bead retention segments;
• and
• wherein the optical signals are optically distinguishable from background signals of the single beads held in the corresponding single bead retention segments.