Photo-responsive polymer micelles from o-nitrobenzyl ester-based amphiphilic block copolymers synthesized by mechanochemical solid-state copolymerization

Dextran-based nanoparticles with 5-FU-conjugated polymethacrylate segments for drug delivery: Synthesis of amphiphilic graft copolymers by mechanochemical solid-state polymerization and characterization

Dextran (Dx) is a biodegradable and biocompatible polysaccharide, thus promising as a drug delivery carrier for tumor therapy. Herein, we applied mechanical energy to a high molecular weight Dx to control its molecular weight and simultaneously generate mechanoradicals. The solid-state polymerization of methacrylate- or methacrylamide derivatives initiated with Dx mechanoradicals showed polymer conversion of >95%, yielding Dx-based graft copolymers with molecular weights of approximately 30,000 g mol-1. The Dx-based graft copolymers with hydrophobic segments formed nanoparticles with a particle size of 25-35 nm in an aqueous solution. The anti-pancreatic tumor drug 5-fluorouracil (5-FU) was covalently conjugated onto the hydrophobic segments of the amphiphilic Dx, and the nanoparticles were also prepared. The drug release profile from 5-FU-conjugated nanoparticles corresponded well to the Korsmeyer-Peppas model applied to drug release from matrix substrates, and was also immensely predicted by the Logistic and Gompertz curves. The 5-FU-conjugated nanoparticles showed cytotoxicity against the pancreatic adenocarcinoma cell lines (BxPC-3) that were not significantly inferior to the 5-FU positive group. Furthermore, the fluorescein-labeled nanoparticles internalized into BxPC-3 within 6 h and actively migrated into the cytosol. These results suggest that Dx-based graft copolymers with hydrophobic segments might be used to enhance therapeutic activity.

Supramolecular nanoarchitectonics of propionylated polyrotaxanes with bulky nitrobenzyl stoppers for light-triggered drug release

Cyclodextrin (CD)-based polyrotaxanes (PRXs) are supramolecular polymers comprising multiple CDs mechanically interlocked onto a linear polymer chain by capping the polymer ends with bulky stoppers. Among various PRX derivatives, propionylated PRXs (Pr-PRXs) composed of propionylated α-CD and high molecular-weight poly(ethylene glycol) (PEG) form self-assembled nanoparticles in aqueous solution through hydrophobic interactions. Although Pr-PRX nanoparticles can encapsulate hydrophobic drugs in their hydrophobic domains, their release rate is limited. To improve the efficiency of drug release from Pr-PRX nanoparticles, ultraviolet (UV) light-dissociable Pr-PRXs were designed using 4,5-dimethoxy 2-nitrobenzyl groups as UV-cleavable bulky stopper molecules to facilitate UV-induced drug release. Photodegradable Pr-PRX (Pr-PD-PRX) was synthesized, and its UV-induced dissociation was examined. Pr-PD-PRX was completely dissociated via UV irradiation (365 nm) for 30 min. Additionally, Pr-PD-PRX nanoparticles encapsulating hydrophobic drugs collapsed upon UV irradiation, which promoted the release of the encapsulated drugs compared to non-degradable Pr-PRX nanoparticles. UV irradiation of drug-loaded Pr-PD-PRX nanoparticles resulted in higher cytotoxicity than non-irradiated Pr-PD-PRX and non-degradable Pr-PRX. Consequently, designing photodegradable PRX-based nanoparticles provides new insights into developing photoresponsive drug carriers and smart biomedical materials.

Smart Polymeric Micelles for Anticancer Hydrophobic Drugs

Cancer has become one of the deadliest diseases in our society. Surgery accompanied by subsequent chemotherapy is the treatment most used to prolong or save the patient's life. Still, it carries secondary risks such as infections and thrombosis and causes cytotoxic effects in healthy tissues. Using nanocarriers such as smart polymer micelles is a promising alternative to avoid or minimize these problems. These nanostructured systems will be able to encapsulate hydrophilic and hydrophobic drugs through modified copolymers with various functional groups such as carboxyls, amines, hydroxyls, etc. The release of the drug occurs due to the structural degradation of these copolymers when they are subjected to endogenous (pH, redox reactions, and enzymatic activity) and exogenous (temperature, ultrasound, light, magnetic and electric field) stimuli. We did a systematic review of the efficacy of smart polymeric micelles as nanocarriers for anticancer drugs (doxorubicin, paclitaxel, docetaxel, lapatinib, cisplatin, adriamycin, and curcumin). For this reason, we evaluate the influence of the synthesis methods and the physicochemical properties of these systems that subsequently allow an effective encapsulation and release of the drug. On the other hand, we demonstrate how computational chemistry will enable us to guide and optimize the design of these micelles to carry out better experimental work.

The mechanochemical synthesis of polymers

Mechanochemistry - the utilization of mechanical forces to induce chemical reactions - is a rarely considered tool for polymer synthesis. It offers numerous advantages such as reduced solvent consumption, accessibility of novel structures, and the avoidance of problems posed by low monomer solubility and fast precipitation. Consequently, the development of new high-performance materials based on mechanochemically synthesised polymers has drawn much interest, particularly from the perspective of green chemistry. This review covers the constructive mechanochemical synthesis of polymers, starting from early examples and progressing to the current state of the art while emphasising linear and porous polymers as well as post-polymerisation modifications.

Mechanochemical Effect on Controlled Drug Release of Konjac Glucomannan Matrix Tablets during Dry Grinding

To design a controlled drug release preparation based on a safe natural material, a Konjac glucomannan (KGM) mixture containing 16.0 w/w% calcium hydroxide (Ca(OH)₂) was ground in a planetary ball mill for 0–120 min. The mechanochemical effect on the physicochemical properties of the KGM ground product was investigated by Fourier-transform infrared spectroscopy (FT-IR), powder X-ray spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and drug release testing. The FT-IR spectra of the ground KGM indicated that the deacetylation reaction of KGM was accelerated in the Ca(OH)₂-containing sols by mechanochemical energy, and the degree of deacetylation of KGM was dependent on the grinding time. The time required for tablet disintegration of the KGM matrix tablets containing theophylline increased as the grinding time increased; therefore, drug release was sustained. The Higuchi plots of the matrix tablets obtained from KGM ground for 60–120 min exhibited good linearity because they maintained their gel matrix tablet shape during the release test. However, KGM tablets ground for 0–30 min exhibited nonlinear curves, which were caused by tablet disintegration. This suggests that drug release from the KGM matrix tablet can be freely controlled by the degree of mechanochemical treatment.

Photo-controlled self-assembly behavior of novel amphiphilic polymers with a rosin-based azobenzene group

Novel ‘bola’ rosin-based photo-responsive amphiphilic polymers PMPn show an extremely high photoresponsive efficiency and various assembly morphological changes.

Highly photosensitive furan acrylate derivatives and their solid-state photopolymerization

Highly photosensitive multifunctional furan acrylate monomers synthesized from biomass furfural can be photopolymerized into polyesters without photoinitiators and solvents.

Polymeric Micro/Nanocarriers and Motors for Cargo Transport and Phototriggered Delivery

Smart polymer-based micro/nanoassemblies have emerged as a promising alternative for transporting and delivering a myriad of cargo. Cargo encapsulation into (or linked to) polymeric micro/nanocarrier (PC) strategies may help to conserve cargo activity and functionality when interacting with its surroundings in its journey to the target. PCs for cargo phototriggering allow for excellent spatiotemporal control via irradiation as an external stimulus, thus regulating the delivery kinetics of cargo and potentially increasing its therapeutic effect. Micromotors based on PCs offer an accelerated cargo-medium interaction for biomedical, environmental, and many other applications. This review collects the recent achievements in PC development based on nanomicelles, nanospheres, and nanopolymersomes, among others, with enhanced properties to increase cargo protection and cargo release efficiency triggered by ultraviolet (UV) and near-infrared (NIR) irradiation, including light-stimulated polymeric micromotors for propulsion, cargo transport, biosensing, and photo-thermal therapy. We emphasize the challenges of positioning PCs as drug delivery systems, as well as the outstanding opportunities of light-stimulated polymeric micromotors for practical applications.