The present invention generally relates to particles, including nanocapsules or other nanoentities, comprising a polymer such as polysialic acid. The particles are able to access the interior of the cells, and/or to procure the intracellular release of the associated drugs. In 5 one aspect, the present invention is directed to nanocapsules or other entities having an exterior or surface comprising a polymer such as polysialic acid. In some cases, targeting moieties such as Lyp-1 or tLyp-1 peptide are bonded to the polymer, e.g., using aminoalkyl (C1-C4) succinimide or other linkers. These may be created, for example, by reacting a carboxylate moiety on a polymer with an aminoalkyl maleimide (C1-C4) or an aminoalkyl 10 (C1-C4) methacrylamide, and reacting the resulting aminoalkyl (C1-C4) maleimide or the aminoalkyl (C1-C4) methacyrlamide to a cysteine or other sulfur group. Targeting moieties are bonded to the polymer, for example, by reacting a carboxylate moiety on a polymer with a N-hydroxysuccinimide or a carbodiimide, and reacting the intermediate formed with a lysine or arginine group on a targeting peptide to produce polymer-amide-peptide. Other 15 aspects of the invention are generally directed to methods of making or using such compositions, kits including such compositions, or the like.La présente invention concerne de manière générale des particules, dont des nanocapsules ou d'autres nanoentités, comprenant un polymère tel que l'acide polysialique. Les particules sont capables d'accéder à l'intérieur des cellules et/ou d'assurer la libération intracellulaire des médicaments associés. Selon un aspect, la présente invention concerne des nanocapsules ou d'autres entités comportant une partie extérieure ou surface comprenant un polymère tel que l'acide polysialique. Dans certains cas, des fractions de ciblage telles que Lyp-1 ou tLyp-1 sont liées au polymère, par exemple à l'aide de succinimide aminoalkylé en C1-C4 ou d'autres séquences de liaison. Lesdites sé
