Effects of copolymer component on the properties of phosphorylcholine micelles

Mucin-mediated mucosal retention via end-terminal modified Pluronic F127-based hydrogel to increase drug accumulation in the lungs

Noninvasive lung drug delivery is critical for treating respiratory diseases. Pluronic-based copolymers have been used as multifunctional materials for medical and biological applications. However, the Pluronic F127-based hydrogel is rapidly degraded, adversely affecting the mechanical stability for prolonged drug release. Therefore, this study designed two thermosensitive copolymers by modifying the Pluronic F127 terminal groups with carboxyl (ADF127) or amine groups (EDF127) to improve the viscosity and storage modulus of drug formulations. β-alanine and ethylenediamine were conjugated at the terminal of Pluronic F127 using a two-step acetylation process, and the final copolymers were characterized using 1H nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectra. According to the 1H NMR spectra, Pluronic F127 was functionalized to form ADF127 and EDF127 with 85 % and 71 % functionalization degrees, respectively. Rheological studies revealed that the ADF127 (15 wt%) and EDF127 (15 wt%) viscosities increased from 1480 Pa.s (Pluronic F127) to 1700 Pa.s and 1800 Pa.s, respectively. Furthermore, the elastic modulus of ADF127 and EDF127 increased, compared with that of native Pluronic F127 with the addition of 5 % mucin, particularly for ADF127, thereby signifying the stronger adhesive nature of ADF127 and EDF127 with mucin. Additionally, ADF127 and EDF127 exhibited a decreased gelation temperature, decreasing from 33 °C (Pluronic F127 at 15 wt%) to 24 °C. Notably, the in vitro ADF127 and EDF127 drug release was prolonged (95 %; 48 h) by the hydrogel encapsulation of the liposome-Bdph combined with mucin, and the intermolecular hydrogen bonding between the mucin and the hydrogel increased the retention time and stiffness of the hydrogels. Furthermore, ADF127 and EDF127 incubated with NIH-3T3 cells exhibited biocompatibility within 2 mg/mL, compared with Pluronic F127. The nasal administration method was used to examine the biodistribution of the modified hydrogel carrying liposomes or exosomes with fluorescence using the IVIS system. Drug accumulation in the lungs decreased in the following order: ADF127 > EDF127 > liposomes or exosomes alone. These results indicated that the carboxyl group-modified Pluronic F127 enabled well-distributed drug accumulation in the lungs, which is beneficial for intranasal administration routes in treating diseases such as lung fibrosis.

In Situ GISAXS Observation and Large Area Homogeneity Study of Slot-Die Printed PS-b-P4VP and PS-b-P4VP/FeCl3 Thin Films

Mesoporous hematite (α-Fe₂O₃) thin films with high surface-to-volume ratios show great potential as photoelectrodes or electrochemical electrodes in energy conversion and storage. In the present work, with the assistance of an up-scalable slot-die coating technique, locally highly ordered α-Fe₂O₃ thin films are successfully printed based on the amphiphilic diblock copolymer poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) as a structure-directing agent. Pure PS-b-P4VP films are printed under the same conditions for comparison. The micellization of the diblock copolymer in solution, the film formation process of the printed thin films, the homogeneity of the dry films in the lateral and vertical direction as well as the morphological and compositional information on the calcined hybrid PS-b-P4VP/FeCl₃ thin film are investigated. Because of convection during the solvent evaporation process, a similar dimple-type structure of vertically aligned cylindrical PS domains in a P4VP matrix developed for both printed PS-b-P4VP and hybrid PS-b-P4VP/FeCl₃ thin films. The coordination effect between the Fe³⁺ ions and the vinylpyridine groups significantly affects the attachment ability of the P4VP chains to the silicon substrate. Accordingly, distinct feature sizes and homogeneity in the lateral direction, as well as the thicknesses in the perpendicular direction, are demonstrated in the two printed films. By removing the polymer template from the hybrid PS-b-P4VP/FeCl₃ film at high temperature, a locally highly ordered mesoporous α-Fe₂O₃ film is obtained. Thus, a facile and up-scalable printing technique is presented for producing homogeneous mesoporous α-Fe₂O₃ thin films.

Using copper sulfide nanoparticles as cross-linkers of tumor microenvironment responsive polymer micelles for cancer synergistic photo-chemotherapy

Photo-chemotherapy presents promising therapeutic effects in cancer treatment. Photo-thermal and chemotherapeutic agents are generally delivered independently or jointly by drug carriers, such as polymer micelles. A polymer micelle is one type of widely researched drug carrier. However, there is a disassembly risk for polymer micelles under excessive dilution in blood circulation, leading to the premature release of payloads from the micelles and finally resulting in undesirable toxic side effects. Herein, amino-PEG decorated copper sulfide nanoparticles (CuS NPs) with photothermal effect were applied as a cross-linker to enhance polymeric micelles' stability and to provide photothermal therapy in the meanwhile. The micelles were prepared using a pH/reductive responsive polymer, poly(ε-caprolactone)-ss-poly(2-(diisopropylamino)ethyl methacrylate/glycidyl methacrylate/2-methylacrylloxyethyl phosphorylcholine (PCL-SS-P(DPA/GMA/MP)), abbreviated as DGM. Cross-linked micelles (DGM-CuS) exhibited high photothermal transformation efficiency and excellent stability against dilution, as well as pH and redox responsive drug release. Under near-infrared laser irradiation, the cell cytotoxicity of doxorubicin-loaded micelles DGM-CuS@DOX and DGM-CuS@DOX-P (DGM-CuS@DOX modified by peptides) increased by 17.1 times and 69.2 times correspondingly compared to that without laser irradiation. All of the solid 4T1 tumors disappeared, and tumor metastases were merely observed in the major organs of the tumor-bearing mice after administration of DGM-CuS@DOX and DGM-CuS@DOX-P with irradiation. In this synergistic therapy system, CuS NPs play double roles of a photothermal agent and a micelle cross-linker. The strategy of utilizing nanoparticles as cross-linkers is newly reported, which offers new insight for combination therapy.

Synergistic action of doxorubicin and 7-Ethyl-10-hydroxycamptothecin polyphosphorylcholine polymer prodrug

There are opportunities for improvements to the efficiency and toxicity of widely used cancer chemotherapy agents such as doxorubicin (DOX·HCl) and 7-Ethyl-10-hydroxycamptothecin (SN38). We developed a safe and effective combination therapy by encapsulating DOX into micelles of a zwitterionic polymer prodrug, SN38 conjugate of poly (α-azide caprolactone-co-caprolactone)-b-poly (2-methacryloyloxyethyl phosphorylcholine [P(CL/CL-g-SN38)-b-PMPC)] which was described in our previous work. The polymer prodrug micelles displayed a higher loading capacity of DOX due to the π-π stacking effect between DOX and SN38 in comparison with the micelles self-assembled by prodrug's precursor, poly(α-azide caprolactone-co-caprolactone)-b-poly(2-methacryloyloxyethyl phosphorylcholine (P(ACL/CL)-b-PMPC). The DOX loaded prodrug micelles decelerated the release of DOX, and also prolonged its circulation. The micelles showed favorable cellular internalization by 4T1 cells. DOX loaded SN38 prodrug micelles displayed good in vitro anticancer effects owing to the synergistic action of doxorubicin and SN38 and were as effective as DOX·HCl, but with lower toxicity than DOX·HCl. Given the synergetic effects of free drug and polymer prodrug, this nanomedicine may offer a safe and effective drug delivery methodology for conventional drug formations.

pH/redox dual-responsive amphiphilic zwitterionic polymers with a precisely controlled structure as anti-cancer drug carriers

Responding to the tumor microenvironment, functional polymers can serve as preeminent drug carriers for targeted cancer therapy. Stimuli-responsive polymeric drug carriers are reported with diverse anti-tumor effects for various polymer structures. Thus, three pH/redox dual-responsive amphiphilic zwitterionic polymer 'isomers' with different locations of pH/redox responsive units were prepared to understand the relationship between polymer structure and anti-tumor effect. Containing poly(ε-caprolactone) (PCL), poly(N,N-diethylaminoethyl methacrylate) (PDEA) and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), polymers PCL-ss-P(DEA-r-MPC) (SDRM), PCL-ss-PDEA-b-PMPC (SDBM) and PCL-PDEA-ss-PMPC (DSM) with a precisely controlled structure were constructed and confirmed through NMR, FITR and EA. The formed micellar drug carriers were characterized by their morphology, loading capacity, acid/redox sensitivity, drug release, in vitro cytotoxicity and in vivo antitumor effects. Micelles with uniform spherical morphologies can effectively encapsulate anti-tumor drugs such as DOX. Among these micelles, DSM@DOX displays the most excellent drug encapsulation capacity (13.4%) with neutral surface charge (-1.02 mV) and good stability, and is different from SDRM@DOX with positive charge (+11.1 mV) and SDBM@DOX with poor stability. All micelles respond to acid and reducing environments and present fast drug release at mildly acidic pH and high concentrations of GSH, exhibiting low burst release under the physiological conditions of plasma. There is no significant difference between these micelles in tumor cell cytotoxicity against MCF-7 and 4T1 cells. Internalization of SDRM@DOX and DSM@DOX by the tumor cells is stronger than that of SDBM@DOX. Notably, DSM@DOX has longer blood circulation and more effective accumulation at the tumor site than the other two micelles. As a result, DSM@DOX shows enhanced antitumor efficacy in 4T1 tumor-bearing mice with reduced side toxicities. Overall, structures of the above polymers significantly influence the in vivo antitumor effects of the drug carriers through blood circulation and cellular uptake.

Synthesis of a SN38 prodrug grafted to amphiphilic phosphorylcholine polymers and their prodrug miceller properties

Polymer prodrug micelles, combining the advantages of prodrugs and polymer micelles, can greatly improve the solubility, permeability and stability of drugs.

Dual tumor-targeted poly(lactic-co-glycolic acid)-polyethylene glycol-folic acid nanoparticles: a novel biodegradable nanocarrier for secure and efficient antitumor drug delivery

Further specific target-ability development of biodegradable nanocarriers is extremely important to promote their security and efficiency in antitumor drug-delivery applications. In this study, a facilely prepared poly(lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-folic acid (FA) copolymer was able to self-assemble into nanoparticles with favorable hydrodynamic diameters of around 100 nm and negative surface charge in aqueous solution, which was expected to enhance intracellular antitumor drug delivery by advanced dual tumor-target effects, ie, enhanced permeability and retention induced the passive target, and FA mediated the positive target. Fluorescence-activated cell-sorting and confocal laser-scanning microscopy results confirmed that doxorubicin (model drug) loaded into PLGA-PEG-FA nanoparticles was able to be delivered efficiently into tumor cells and accumulated at nuclei. In addition, all hemolysis, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, and zebrafish-development experiments demonstrated that PLGA-PEG-FA nanoparticles were biocompatible and secure for biomedical applications, even at high polymer concentration (0.1 mg/mL), both in vitro and in vivo. Therefore, PLGA-PEG-FA nanoparticles provide a feasible controlled-release platform for secure and efficient antitumor drug delivery.

Phosphorylcholine micelles decorated by hyaluronic acid for enhancing antitumor efficiency

DOX-loaded PCL-PDEAMPC micelles coated with HA by electrostatic attraction for enhancing antitumor efficiency and prolonging blood circulation time.

Cellular uptake of pH/reduction responsive phosphorylcholine micelles

We study the relationship between the PDEA content and internalization/intracellular drug release of pH responsive phosphorylcholine micelles as drug carriers.