Understanding the intracellular distribution and tra_x001e_cking of nanoparticle drug carriers is necessary to elucidate their mechanisms of drug delivery and is helpful in the rational design of novel nanoparticle drug delivery systems. The traditional immuno uorescence method to study intracellular distribution of nanoparticles using organellespeci c antibodies is laborious and subject to artifacts. As an alternative, we developed a new method that exploits ratiometric uorescence imaging of a pH-sensitive Lysosensor dye to visualize and quantify the spatial distribution of nanoparticles in the endosomes and lysosomes of live cells. Using this method, we compared the endo-lysosomal distribution of cell penetr... More
Understanding the intracellular distribution and tra_x001e_cking of nanoparticle drug carriers is necessary to elucidate their mechanisms of drug delivery and is helpful in the rational design of novel nanoparticle drug delivery systems. The traditional immuno uorescence method to study intracellular distribution of nanoparticles using organellespeci c antibodies is laborious and subject to artifacts. As an alternative, we developed a new method that exploits ratiometric uorescence imaging of a pH-sensitive Lysosensor dye to visualize and quantify the spatial distribution of nanoparticles in the endosomes and lysosomes of live cells. Using this method, we compared the endo-lysosomal distribution of cell penetrating peptide (CPP)-functionalized micelles to unfunctionalized micelles, and found that CPP-functionalized micelles exhibited faster endosome-tolysosome tra cking than unfunctionalized micelles. Ratiometric uorescence imaging 1 Page 1 of 20 ACS Paragon Plus Environment Nano Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 of pH-sensitive Lysosensor dye allows rapid quantitative mapping of nanoparticle distribution in endo-lysosomes in live cells while minimizing artifacts caused by extensive sample manipulation typical of alternative approaches. This new method can thus serve as an alternative to traditional immuno uorescence approaches to study the intracellular distribution and tra cking of nanoparticles within endosomes and lysosomes.
