Active targeting of nanoscale drug service providers can improve tumor-specific delivery;

Active targeting of nanoscale drug service providers can improve tumor-specific delivery; BGJ398 however cellular heterogeneity both within and among Felypressin Acetate tumor sites is definitely a fundamental barrier to their success. cells. Hypoxic pH-induced structural reorganization of hyaluronan-LbL nanoparticles was a direct result of the nature of the LbL electrostatic complex and led to targeted cellular delivery and stability of restorative RNA for efficacious synergistic siRNA/drug combination therapy 26 28 or incorporate nanoparticle cores comprising diagnostic imaging providers23 and cytotoxic chemotherapeutics.26 27 Here we engineer a novel LbL nanoparticle architecture that actively focuses on stable tumors through two indie mechanisms: selective binding to cell-surface CD44 receptor and acid-induced cellular delivery at hypoxic tumor pH. BGJ398 This approach allows for the creation of nanoparticles that respond to the tumor microenvironment in two unique ways thus greatly enhancing focusing on and uptake. Rather than employing nondegradable neutral polymers such as poly(ethylene glycol) synthetic ligand attachment or complex linker chemistry we accomplish an intrinsic responsive behavior through the simple use of biologically derived weak polyelectrolytes inside a self-assembled thin film. 2 LbL films assembled from partially ionized or “fragile” polyelectrolytes are well-known to exhibit dynamic structure and stability with respect to pH compared with their strong polyelectrolyte counterparts.34?36 For example dramatic shifts in BGJ398 adsorbed BGJ398 coating thickness surface morphology and effective ionic cross-link denseness have been observed due to thermodynamic trade-offs and weak Coulombic relationships between nearest-neighbor proton binding sites.36 The hypoxic microenvironment of stable tumors also show a narrow gradient in pH; poor blood perfusion and quick metabolic usage of oxygen results in a drop in pH from 7.4 (normoxic) to <6.6 in distances as short as 150 μm from your vessel wall 37 providing an environment that can select for and sponsor aggressive and metastatic cell phenotypes.38 One of the challenges in nanoparticle design for cancer treatment is their infiltration and penetration through the stroma and into tumor tissues and selective uptake of nanoparticles within the tumor tissue. We hypothesized that LbL nanoparticle architectures incorporating practical biopolymers that themselves are fragile polyelectrolytes may accomplish both receptor-targeting pH-triggered engagement of and delivery to solid tumors without the need for ligand coupling chemistries active proteins or stealth layers that can expose potential issues with compatibility immune response or blood half-life. To this end we selected a fragile polyamine poly(l-lysine) which is a synthetic polypeptide from a natural amino acid and a complementary fragile polyacid hyaluronan (HA) which is a native extracellular matrix polysaccharide to serve as practical components of this dual-targeting LbL drug carrier. While both polyelectrolytes are biocompatible pharmaceutical excipients (sequential adsorption and centrifugation from solutions of aqueous hyaluronan and poly(l-lysine) as explained previously.20Figure ?Number22a b illustrates the progressive increase in hydrodynamic size and related shift in surface charge of the nanoparticles during the LbL assembly process yielding particles 135 ± 4 nm in hydrodynamic diameter and ?33 ± 1 mV in zeta potential. Transmission electron micrographs (Number ?Number22c) and cross-sectional 3D renderings of energy-filtered transmission electron microscopy (TEM) images (EFTEM Figure ?Number22d) confirmed structural partitioning between the carbon-rich polystyrene nanoparticle core and the oxygen-rich LbL multilayered shell. Notably thickness increases from your terminal HA coating (20 ± 2 nm) appeared larger than typically observed from other fragile and strong polyelectrolytes (4-5 nm).23 In solution HA’s conformation is composed of a combination of random coil and helical structures the latter of which can self-associate and entangle through relationships between outer hydrophobic pocket regions of the helices.47 In LbL films Burke find that HA undergoes an significant increase in secondary conformational ordering and intermolecular H bonding.48 We hypothesize that surface-induced helical ordering of HA on LbL nanoparticles results in increased self-association between surface-bound HA chains that leads to non-surface-limited coverages observed here. HA-LbL nanoparticles were well-dispersed (PDI 0.11 ± 0.01) and exhibited few (<1.2%) dimers and no (0%) higher order aggregates. The solid coating of HA on the exterior surface provides an.