Magnetic nanoparticle-conjugated polymeric micelles (MNP-PMs) consisting of poly(ethylene glycol)-poly(lactide) (PEG-PLA) and iron oxide nanoparticles were prepared and used as nanocarriers for combined hyperthermia and chemotherapy. Doxorubicin (DOX) was encapsulated in MNP-PMs, and an alternating magnetic field (AMF) resulted in an increase to temperature within a suitable range for inducing hyperthermia and a higher rate of drug release than observed without AMF. In vitro cytotoxicity and hyperthermia experiments were carried out using human lung adenocarcinoma A549 cells. When MNP-PMs encapsulated with an anticancer drug were used to treat A549 cells in combination with hyperthermia under AMF, 78% of the cells were killed by the double effects of heat and the drug, and the combination was more effective than either chemotherapy or hyperthermia treatment alone. Therefore, MNP-PMs encapsulated with an anticancer drug show potential for combined chemotherapy and hyperthermia.

Among the starting materials of thermoplastic polyurethanes (TPUs), it was confirmed that succinic acid-based polyester biopolyols having different molecular weights (M_n = 1000, 2000, and 4000) affect the physicochemical properties of the final polymer significantly. Bio-TPUs synthesized through a solvent-free one-shot polymerization process were synthesized with a polyester polyol, 1,4 butanediol (BDO), and 4,4′-methylene diphenyl diisocyanate (MDI) in a molar ratio of 1:1:2. As a control group, one typical petroleum-based TPU was synthesized and characterized along with other bio-based TPUs. Representative petroleum-based and bio-based TPUs synthesized were manufactured as monofilaments with a diameter of about 0.2 mm through an extrusion process with different draw ratios (4, 5, and 6 times). The molecular weight and structural properties of the TPUs were characterized by GPC and FT-IR analysis and thermal characterization by DSC and TGA analysis. Petroleum-based TPU and bio-based TPU having the same molecular weight soft segment (SS) tended to have similar molecular weight and hard segment (HS) content. TPUs with high HS content had excellent thermal stability, enabling stable extrusion of TPUs. In addition, it was confirmed that the bio-based TPU fibers produced in this way had a tensile strength corresponding to the physical properties of petroleum-based TPU fibers and an excellent elastic recovery rate of almost 100 %. These results indicate the application potential of bio-TPU.

In this study, side-by-side bicomponent fibers were prepared by melt spinning using bio-based thermoplastic polyurethane (TPU) and TPU/polylactic acid (PLA) blends. The morphology, thermal and mechanical properties of the fibers were investigated. To this end, the synthesis of TPU using biomass-based polyols and the preparation of TPU/PLA blends were preceded. Their morphological and structural characteristics were investigated. The synthesis of TPU was confirmed through Fourier transform infrared analysis, and as a result of gel permeation chromatograph analysis, a compound having a weight average molecular weight of 196,107 was synthesized. The TPU/PLA blends were blended in the ratio of 80/20, 60/40, 40/60, and 20/80 through a melt extruder. They formed a sea–island structure as a result of scanning electron microscope analysis, and an increase in the PLA content in the TPU matrix caused a decrease in the melt flow index. Finally, TPU/(TPU/PLA) side-by-side bicomponent fibers were prepared by utilizing the above two materials. These fibers exhibited tensile strengths of up to 3624 MPa, with improved biocarbon content of up to 71.5%. These results demonstrate the potential of TPU/(TPU/PLA) side-by-side bicomponent fibers for various applications.

Polymeric micelles as drug delivery vehicles are popular owing to several advantages. In this study, a gemini amphiphile (gemini mPEG-Cys-PMT) consisting of hydrophilic poly(ethylene glycol) and hydrophobic poly(methionine) with cystine disulfide spacer was synthesized and its micellar properties for thiol- or reactive oxygen species (ROS)-dependent intracellular drug delivery were described. The cleavage of cystine linkage in a redox environment or the oxidation of methionine units in a ROS environment caused the destabilization of micelles. Such redox- or ROS-triggered micellar destabilization led to enhanced release of encapsulated doxorubicin (DOX) to induce cytotoxicity against cancer cells. Further, the therapeutic effects of the DOX-loaded micelles were demonstrated using the KB cell line. This study shows that thiol and ROS dual-responsive gemini micelles are promising platforms for nano-drug delivery in various cancer therapies.