an integrated on-chip probe body having a distal tip end, a proximal end and a microfluidic channel extending between the distal tip end and the proximal end, wherein the microfluidic channel is embedded within a probe body cross-section configured for implantation into biological tissue with a cross-sectional area less than or equal to 10,000 μm²;

a microchannel opening at the distal tip end for providing the biological fluid or the analyte of the biological fluid to the microfluidic channel;

an immiscible fluid microchannel that fluidically connects with the microfluidic channel to form a microfluidic junction for segmenting the biological fluid or the analyte of the biological fluid into a train of a sample-containing fluid, wherein adjacent sample-containing fluid segments from the microchannel opening are separated by an immiscible fluid configured to be introduced by the immiscible fluid microchannel;

a fluid outlet positioned at the probe body proximal end and in fluidic contact with the microfluidic channel;

a flow controller fluidically connected to the microfluidic channel and the immiscible fluid microchannel to control flow of the sample-containing fluid segments separated by the immiscible fluid in the microfluidic channel and to collect the sample-containing fluid segments separated by the immiscible fluid in the microfluidic channel; and

a fluid storage system for temporary storage of a train of the sample-containing fluid segments separated by the immiscible fluid, wherein the temporary storage maintains temporal collection of the biological fluid or the analyte of the biological fluid collected into the microfluidic channel;

wherein the integrated on-chip probe is configured to provide sampling, storage and sample emission or detection for the analyte of the biological fluid in a unitary material that forms the probe body.