Methods for delivering an analyte to transmembrane pores

A method for delivering an increased concentration of a polynucleotide analyte to a transmembrane pore in a membrane, comprising:

• (a) providing the polynucleotide analyte attached to a microparticle;
• (b) delivering the microparticle towards the membrane, thereby delivering the polynucleotide analyte to the transmembrane pore;
• (c) allowing the polynucleotide analyte to interact with the transmembrane pore under conditions in which a polynucleotide binding protein, bound to the polynucleotide analyte, controls movement of the polynucleotide analyte, wherein the polynucleotide analyte is eluted from the microparticle and moves with respect to the transmembrane pore, wherein the concentration of the polynucleotide analyte delivered to the transmembrane pore is increased by at least about 10-fold;
• and
• (d) taking measurements as the polynucleotide moves with respect to the pore, wherein the measurements are indicative of characteristics of the polynucleotide, and thereby characterising the polynucleotide.