zn(ii)-phthalocyanine and benzeneboronic-acid

Herein, we report a ligand-reversible-shielding strategy based on the mutual shielding of dual ligands tethered to the surface of nanoparticles. To exemplify this concept, phenylboronic acid-functionalized poly(ethylene glycol)- b-poly(ε-caprolactone) (PBA-PEG-PCL) and galactose-functionalized diblock polymer (Gal-PEG-PCL) were mixed to form dual-ligand micelles (PBA/Gal). PBA and Gal residues could form a complex at pH 7.4 and mutually shield their targeting function. At pH 6.8, the binding affinity between PBA and Gal weakened, and PBA preferred to bind with the sialic acid residues on the tumor cell surface rather than to Gal on the micellar surface; furthermore, the unbound Gal recovered its targeting ability toward the asialoglycoprotein receptor. When the pH decreased from 7.4 to 6.8, enzyme-linked immunosorbent assays exhibited that the percentage of exposed Gal on the micellar surface increased 1.9-fold, and flow cytometry showed that HepG2 cellular uptake increased 4.3-fold. More importantly, this process was reversible, confirming the reversible shielding and deshielding of dual ligands. With the encapsulation of a photosensitizer, zinc phthalocyanine (ZnPc), the reversible-shielding micelles showed a 48% improvement in the half-life ( t

Topics: Boronic Acids; Drug Carriers; Ethylene Glycols; Hep G2 Cells; Humans; Hydrogen-Ion Concentration; Indoles; Isoindoles; Lactones; Ligands; Micelles; Nanoparticles; Neoplasms; Organometallic Compounds; Polyesters; Polyethylene Glycols; Polymers; Zinc Compounds