RESUMEN
Dual responsive polymer nanoscaffolds for administering anticancer drugs both at the tumor site and intracellular compartments are made for improving treatment in cancers. The present work reports the design and development of new thermo- and enzyme-responsive amphiphilic copolymer core-shell nanoparticles for doxorubicin delivery at extracellular and intracellular compartments, respectively. A hydrophobic acrylate monomer was tailor-made from 3-pentadecylphenol (PDP, a natural resource) and copolymerized with oligoethylene glycol acrylate (as a hydrophilic monomer) to make new classes of thermo and enzyme dual responsive polymeric amphiphiles. Both radical and reversible addition-fragmentation chain transfer (RAFT) methodologies were adapted for making the amphiphilic copolymers. These amphiphilic copolymers were self-assembled to produce spherical core-shell nanoparticles in water. Upon heating, the core-shell nanoparticles underwent segregation to produce larger sized aggregates above the lower critical solution temperature (LCST). The dual responsive polymer scaffold was found to be capable of loading water insoluble drug, such as doxorubicin (DOX), and fluorescent probe-like Nile Red. The drug release kinetics revealed that DOX was preserved in the core-shell assemblies at normal body temperature (below LCST, ≤ 37 °C). At closer to cancer tissue temperature (above LCST, â¼43 °C), the polymeric scaffold underwent burst release to deliver 90% of loaded drugs within 2 h. At the intracellular environment (pH 7.4, 37 °C) in the presence of esterase enzyme, the amphiphilic copolymer ruptured in a slow and controlled manner to release >95% of the drugs in 12 h. Thus, both burst release of cargo at the tumor microenvironment and control delivery at intracellular compartments were accomplished in a single polymer scaffold. Cytotoxicity assays of the nascent and DOX-loaded polymer were carried out in breast cancer (MCF-7) and cervical cancer (HeLa) cells. Among the two cell lines, the DOX-loaded polymers showed enhanced killing in breast cancer cells. Furthermore, the cellular uptake of the DOX was studied by confocal and fluorescence microscopes. The present investigation opens a new enzyme and thermal-responsive polymer scaffold approach for DOX delivery in cancer cells.
Asunto(s)
Antibióticos Antineoplásicos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Doxorrubicina/farmacología , Portadores de Fármacos/síntesis química , Nanopartículas/química , Neoplasias del Cuello Uterino/tratamiento farmacológico , Antibióticos Antineoplásicos/administración & dosificación , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/administración & dosificación , Portadores de Fármacos/administración & dosificación , Portadores de Fármacos/farmacología , Liberación de Fármacos , Glicol de Etileno/química , Femenino , Células HeLa , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Líquido Intracelular , Células MCF-7 , Fenoles/química , Polimerizacion , Polímeros/química , Tensoactivos/química , Temperatura , Microambiente Tumoral/efectos de los fármacosRESUMEN
The present investigation reports the development of a super LCST thermo-responsive amphiphilic nanoparticle assembly for the detection of adenosine triphosphate (ATP) through the Hofmeister effect. For this purpose, a new diblock molecule was designed based on hydrophilic polyethylene glycol and the renewable resource 3-pendadecylphenol as the hydrophobic unit. The amphiphile self-assembled as a 150 nm micellar nanoparticle and showed a super lower critical solution temperature (LCST) above 90 °C. The amphiphile followed the Hofmeister effect for the anion series and exhibited high selectivity for the recognition of ATP over its adenosine precursors such as ADP, AMP and inorganic phosphate (Pi). The preferential binding for ATP is attributed to the encapsulation in the hydrophobic pocket and modification of the hydration shell at the periphery of the amphiphilic nanoparticles. Electron and atomic force microscopes and dynamic light scattering techniques confirmed the size and shape of the amphiphilic assembly and its ATP complexes. Isothermal calorimetric experiments were carried out to determine the binding constants for the amphiphilic nanoparticle binding to ATP. The binding of the amphiphilic nanoparticle to ATP was found to be an endothermic process with a binding constant three times higher compared to its precursor Pi. This investigation provides the first insight into the development of a thermo-responsive scaffold for recognition of ATP.
RESUMEN
Shape transformable carriers are an important class of biomaterials for selective drug delivery in a cancer tissue physiological environment. Here, we report the first example of an in situ shape transformable thermo-responsive amphiphilic scaffold for loading and delivering anticancer drugs at the cancer tissue temperature. New amphiphiles having a hydrogen bonded amide linkage that connects hydrophilic oligoethylene glycol with the hydrophobic renewable resource 3-pendadecylphenol were tailor made through multi-step organic synthesis. These amphiphiles underwent reversible self-assembly from three dimensional core-shell to rod-like structures in water (or PBS at pH = 7.4). The temperature-induced shape transformation was attributed to the lower critical solution temperature (LCST) and the process was confirmed by light scattering studies, electron microscopy, atomic force microscopy, variable temperature NMR and single crystal structure study. Anticancer drugs such as doxorubicin (DOX) and camptothecin (CPT) were successfully loaded in the core-shell structure without altering the shape transformation ability of the scaffold. In vitro drug release studies revealed that the DOX loaded scaffolds showed a selective release of more than 90% of the drug at the cancer tissue temperature (40-43 °C) compared to normal body temperature (37 °C, <10%). The drug kinetics study revealed that the release of DOX at the cancer tissue temperature followed a non-Fickian diffusion process. Thus, the present investigation provides the first insight into the development of in situ shape transforming thermo-responsive scaffolds and also establishes the proof-of-concept of their loading and delivering capabilities at the cancer tissue temperature.
RESUMEN
Synthetic macromolecular diblocks sorting into mutivesicular bodies (MVBs) and their fluorophore encapsulation pathways were reported. Renewable resource based diblocks having hydrophobic units and flexible hydrophilic polyethylene glycols (PEG) were custom designed for the above purpose. Single crystal structure was resolved to prove the existence of the strong intermolecular interactions and the formation of unilamellar layer-like self-assemblies. These amphiphilic AB diblocks underwent selective vesicular fission either by outward budding or inward invagination to produce small unilamellar vesicles (SUVs) or MVBs, respectively. Self-organization parameters such as relative volume (ν(e)) and reduced area difference (Δa(0)) were determined on the basis of theoretical models, and very good correlation with the experimental results was established for the synthetic-MVBs. Pyrene was encapsulated to study the mechanistic aspects of the MVB formations. An unusual nonlinear trend was observed in the pyrene dynamic excimer formation with respect to the sorting of diblock membrane into MVBs. Strong intermolecular interaction was found to be a critical deciding factor in synthetic diblock membranes to facilitate MVBs. The approach demonstrated here opens up new design strategies for biomimicking of MVBs in synthetic macromolecules which are potential vectors for drug delivery.