Preparation of mixed micelles carrying folates and stable radicals through PLA stereocomplexation for drug delivery

Synthesis approaches of amphiphilic copolymers for spherical micelle preparation: application in drug delivery

The formation of polymeric micelles in aqueous environments through the self-assembly of amphiphilic polymers can provide a versatile platform to increase the solubility and permeability of hydrophobic drugs and pave the way for their administration. In comparison to various self-assembly-based vehicles, polymeric micelles commonly have a smaller size, spherical morphology, and simpler scale up process. The use of polymer-based micelles for the encapsulation and carrying of therapeutics to the site of action triggered a line of research on the synthesis of various amphiphilic polymers in the past few decades. The extended knowledge on polymers includes biocompatible smart amphiphilic copolymers for the formation of micelles, therapeutics loading and response to external stimuli, micelles with a tunable drug release pattern, etc. Different strategies such as ring-opening polymerization, atom transfer radical polymerization, reversible addition-fragmentation chain-transfer, nitroxide mediated polymerization, and a combination of these methods were employed to synthesize copolymers with diverse compositions and topologies with the proficiency of self-assembly into well-defined micellar structures. The current review provides a summary of the important polymerization techniques and recent achievements in the field of drug delivery using micellar systems. This review proposes new visions for the design and synthesis of innovative potent amphiphilic polymers in order to benefit from their application in drug delivery fields.

Hypoxia-Responsive Stereocomplex Polymeric Micelles with Improved Drug Loading Inhibit Breast Cancer Metastasis in an Orthotopic Murine Model

Tumor metastasis is a leading cause of breast cancer-related death. Taxane-loaded polymeric formulations, such as Genexol PM and Nanoxel M using poly(ethylene glycol)-poly(d,l-lactide) (PEG-PLA) micelles as drug carriers, have been approved for the treatment of metastatic breast cancer. Unfortunately, the physical instability of PEG-PLA micelles, leading to poor drug loading, premature drug leakage, and consequently limited drug delivery to tumors, largely hinders their therapeutic outcome. Inspired by the enantiomeric nature of PLA, this work developed stereocomplex PEG-PLA micelles through stereoselective interactions of enantiomeric PLA, which are further incorporated with a hypoxia-responsive moiety used as a hypoxia-cleavable linker of PEG and PLA, to maximize therapeutic outcomes. The results showed that the obtained micelles had high structural stability, showing improved drug loading for effective drug delivery to tumors as well as other tissues. Especially, they were capable of sensitively responding to the hypoxic tumor environment for drug release, reversing hypoxia-induced drug resistance and hypoxia-promoted cell migration for enhanced bioavailability under hypoxia. In vivo results further showed that the micelles, especially at a high dose, inhibited the growth of the primary tumor and improved tumor pathological conditions, consequently remarkably inhibiting its metastasis to the lungs and liver, while not causing any systemic toxicity. Hypoxia-responsive stereocomplex micelles thus emerge as a reliable drug delivery system to treat breast cancer metastasis.

Machine Learning-Driven Biomaterials Evolution

Biomaterials is an exciting and dynamic field, which uses a collection of diverse materials to achieve desired biological responses. While there is constant evolution and innovation in materials with time, biomaterials research has been hampered by the relatively long development period required. In recent years, driven by the need to accelerate materials development, the applications of machine learning in materials science has progressed in leaps and bounds. The combination of machine learning with high-throughput theoretical predictions and high-throughput experiments (HTE) has shifted the traditional Edisonian (trial and error) paradigm to a data-driven paradigm. In this review, each type of biomaterial and their key properties and use cases are systematically discussed, followed by how machine learning can be applied in the development and design process. The discussions are classified according to various types of materials used including polymers, metals, ceramics, and nanomaterials, and implants using additive manufacturing. Last, the current gaps and potential of machine learning to further aid biomaterials discovery and application are also discussed.

Flexible polymeric nanosized micelles for ophthalmic drug delivery: research progress in the last three years

The eye is a complex structure with a variety of anatomical barriers and clearance mechanisms, so the provision of safe and effective ophthalmic drug delivery technology is a major challenge. In the past few decades, a number of reports have shown that nano-delivery platforms based on polymeric micelles are of great interest, because of their hydrophobic core that encapsulates lipid-soluble drugs and small size with high penetration, allowing long-term drug retention and posterior penetration in the eye. Furthermore, as an ocular delivery platform, polymeric micelles not only cover the single micellar drug delivery system formed by poloxamer, chitosan or other polymers, but also include composite drug delivery systems like micelle-encapsulated hydrogels and micelle-embedded contact lenses. In this review, a number of ophthalmic micelles that have emerged in the last three years will be systematically reviewed, with a summary of and discussion on their unique advantages or unique drug delivery performance. Last but not least, the current challenges of polymeric micelle formulations in potential clinical ophthalmic therapeutic applications will also be proposed, which might be helpful for future design of ocular drug delivery formulations.

Effect of poly (lactic acid) porous membrane prepared via phase inversion induced by water droplets on 3T3 cell behavior

Phase inversion induced by water droplets has garnered attention in the field of polymer science as a novel method for preparing porous membranes. This study investigates the effect of the porous structure of poly (lactic acid) (PLA) membranes prepared through phase inversion induced by water droplets at four different temperatures (25, 50, 75, and 100 °C) on the morphology and proliferation of 3T3 cells. The surface properties of the PLA porous membrane, including pore size, pore size distribution, surface roughness, surface hydrophilicity, and cytocompatibility with 3T3 cells, were evaluated. The results indicated that the synthesized PLA membrane had two surfaces with different structures. The upper surface in contact with the water droplets during preparation contained uniformly distributed micropores, whereas the bottom surface was smooth and composed of small particles in contacted with the mold. The upper surface showed high cytocompatibility with 3T3 cells, and the 3T3 cells migrated and grew within the pores at 25 °C. In contrast, the bottom surface exhibited low biocompatibility with the 3T3 cells. Our study has wide-ranging implications and will improve the fabrication and implementation of 3D cultured scaffolds with excellent cytocompatibility.

AuNPs Decorated PLA Stereocomplex Micelles for Synergetic Photothermal and Chemotherapy

A unique platform for combined photothermal and chemotherapy using PLA stereocomplex (PLA SC) micelles-induced hybrid gold nanocarriers is designed. The PLA SC micelles, made from the self-assembly of poly(ethylene glycol)-block-poly(l-lactide) (PEG-PLLA) and poly(2-(dimethylamino) ethyl methacrylate)-block-poly(d-lactide) (PDMAEMA-PDLA), for the first time are used as a template to fabricate the hybrid PLA SC@Au core-shell nanocarriers, in which the anticancer drugs are encapsulated within the core, while the Au nanoparticles are tethered in the shell via the in situ reduction of AuCl₄ ^- by PDMAEMA. The obtained PLA SC@Au hybrid nanocarriers exhibit low toxicity and remarkable photothermal effect. Upon near-infrared laser irradiation, the on-site photothermal therapy can further induce an accelerated drug release from the hybrid nanocarrier reservoir via hyperthermia heating of the nanocarriers, thus leading to a synergistic photothermal and chemotherapy toward a significantly improved efficacy in tumor shrinkage. The as-designed PLA SC@Au hybrid nanocarriers, with their biocompatible compositions, dual-drug delivery characteristics, and combined photothermal/chemotherapy, show high potential as a novel platform for cancer treatment.

Self-assembled phospholipid-based mixed micelles for improving the solubility, bioavailability and anticancer activity of lenvatinib

The clinical efficacy of lenvatinib (LFT) is limited by its poor aqueous solubility and low bioavailability. In this work, LFT-loaded soy phospholipid and sodium glycocholate mixed micelles (LFT-MMs) were prepared through classical co-precipitation. And it was served as an oral administration to address these shortcomings. The preparation conditions were optimized by single-factor experiments. The mass ratio of PC, SGC and LFT, and the species of dispersing media were proved to be decisive factors in controlling the properties of LFT-MMs. The optimal LFT-MMs presented prominent enhancement (500-fold) in LFT solubility, high encapsulation efficiency (87.6 %) as well as suitable stability (>1 month at 4 °C). The biocompatibility of LFT-MMs was estimated by in vitro serum stability measurement and hemolysis test. It showed that serum proteins hardly adhered to the surface of LFT-MMs, and insignificant hemolytic rate (<0.5 %) was observed at the micelles concentration below 1 mg/mL. Cytotoxicity test (MTT assay) was carried out to judge the in vitro antitumor activity. LFT-MMs showed an enhanced inhibitory activity against two main kinds of differentiated thyroid cancer cells over LFT and LFT Mesylate. To estimate the in vivo oral bioavailability of LFT-MMs, SD rats were used as animal model. Notably, the relative bioavailability of LFT-MMs compared with the original form of LFT was 176.7 %. These superior characteristics indicated that the mixed micelles are promising water-soluble formulations suitable for LFT oral delivery.

Folic acid-appended galactoxyloglucan-capped iron oxide nanoparticles as a biocompatible nanotheranostic agent for tumor-targeted delivery of doxorubicin

Iron oxide nanoparticles (IONPs) are employed as MRI contrast agents and as effective drug delivery vehicles. However, the limited solubility and biodegradability of these nanoparticles need to be improved for safer biomedical applications. In an attempt to improve the bottlenecks associated with IONPs, the current study focuses on the synthesis of folic acid conjugated, galactoxyloglucan-iron oxide nanoparticles (FAPIONPs), for the loading and controlled release of the encapsulated chemotherapeutic agent doxorubicin (DOX). The as-designed DOX@FAPIONPs induced a dose-dependent increase in cytotoxicity in folate receptor-positive cells through a caspase-mediated programmed cell death pathway while bare DOX demonstrated a non-targeted toxicity profile. Using LC-MS/MS analysis, several major biological processes altered in treated cells, from which, cell cycle, cellular function and maintenance were the most affected. Detailed toxicity studies in healthy mice indicated the absence of any major side effects while bare drugs created substantial organ pathology. Gadolinium-based contrast agents have a risk of adverse effects, including nephrogenic systemic fibrosis overcome by the administration of DOX@FAPIONPs in xenograft mice model. Tumor-targeted biodistribution pattern with a favorable DOX pharmacokinetics will be the driving factor behind the appealing tumor reduction capacity and increased survival benefits demonstrated on solid tumor-bearing mice.

Design of naturally inspired jellyfish-shaped cyclopolylactides to manage osteosarcoma cancer stem cells fate

We report the synthesis, characterization and biological profile of new bis-triazoled cyclopolylactides (c-PLA, c-PLA-FA, c-PLA-Rhod) obtained by an optimized combination of ROP and click chemistry reactions. Cyclo-PLA having a number average molecular weight of 6000 g mol^-1 and a polydispersity index of 1.52 was synthetized by click ring-closure of well-defined α,ω-heterodifunctional linear precursors, followed by quaternarization of N₃-triazole nodes, and subsequent CuAAC with azido-folate and azido-rhodamine yielding jellyfish-shaped c-PLA-FA and c-PLA-Rhod. Salinomycin (Sal) was loaded into jellyfish-shaped c-PLA-FA and c-PLA-Rhod nanoparticles (NPs) by nanoprecipitation, with a good encapsulation efficiency (79% and 84%, respectively) and loading content (7.1% and 7.6%, respectively). The biological studies focused on their antiproliferative effects on osteosarcoma bulk MG63 and cancer stem cells (CSCs). The cycloPLA-based NPs, with a size ranging between 125 and 385 nm, killed CSCs and MG63, with a higher efficacy on CSCs; they (unloaded or Sal-loaded) evoked on CSCs a cellular response similar to the payload, with a higher effect than the free Sal. Internalization studies indicated a fast cellular uptake (within 2 h) and sarcospheres remained fluorescent till 72 h. To the best of our knowledge, this is the first study reporting anti-CSCs properties of cycloPLA with jellyfish architecture and we believe could contribute to the development of effective strategies for osteosarcoma targeting.