Poly(ε-caprolactone) (PCL) Hollow Nanoparticles with Surface Sealability and On-Demand Pore Generability for Easy Loading and NIR Light-Triggered Release of Drug

Localized Therapeutic Approaches Based on Micro/Nanofibers for Cancer Treatment

Cancer remains one of the most challenging health problems worldwide, and localized therapeutic approaches based on micro/nanofibers have shown potential for its treatment. Micro/nanofibers offer several advantages as a drug delivery system, such as high surface area, tunable pore size, and sustained release properties, which can improve drug efficacy and reduce side effects. In addition, functionalization of these fibers with nanoparticles can enhance their targeting and therapeutic capabilities. Localized delivery of drugs and/or other therapeutic agents via micro/nanofibers can also help to overcome the limitations of systemic administration, such as poor bioavailability and off-target effects. Several studies have shown promising results in preclinical models of cancer, including inhibition of tumor growth and improved survival rates. However, more research is needed to overcome technical and regulatory challenges to bring these approaches to clinical use. Localized therapeutic approaches based on micro/nanofibers hold great promise for the future of cancer treatment, providing a targeted, effective, and minimally invasive alternative to traditional treatments. The main focus of this review is to explore the current treatments utilizing micro/nanofibers, as well as localized drug delivery systems that rely on fibrous structures to deliver and release drugs for the treatment of cancer in a specific area.

Light-responsive polyurethanes: classification of light-responsive moieties, light-responsive reactions, and their applications

Stimuli responsiveness has been an attractive feature of smart material design, wherein the chemical and physical properties of the material can be varied in response to small environmental change. Polyurethane (PU), a widely used synthetic polymer can be upgraded into a light-responsive smart polymer by introducing a light-sensitive moiety into the polymer matrix. For instance, azobenzene, spiropyran, and coumarin result in reversible light-induced reactions, while o-nitrobenzyl can result in irreversible light-induced reactions. These variations of light-stimulus properties endow PU with wide ranges of physical, mechanical, and chemical changes upon exposure to different wavelengths of light. PU responsiveness has rarely been reviewed even though it is known to be one of the most versatile polymers with diverse ranges of applications in household, automotive, electronic, construction, medical, and biomedical industries. This review focuses on the classes of light-responsive moieties used in PU systems, their synthesis, and the response mechanism of light-responsive PU-based materials, which also include dual- or multi-responsive light-responsive PU systems. The advantages and limitations of light-responsive PU are reviewed and challenges in the development of light-responsive PU are discussed.

Biodegradable polycaprolactone (PCL) based polymer and composites

Polycaprolactone (PCL) is a biodegradable polyester that has advantages over other biopolymers, making it an extensively researched polymer. PCL is a hydrophobic, slow-degrading, synthetic polymer making it particularly interesting for the preparation of long-term implantable devices and a variety of drug delivery systems. Recently, PCL has been used for additional applications including food packaging and tissue engineering. In this chapter, the processing methods and characterization of PCL will be discussed. The chapter will summarize the synthesis of poly(α-hydroxy acid) and the ring-opening polymerization of PCL. Discussion on the biodegradability of PCL will be reviewed. The biomedical applications of PCL, such as, drug-delivery systems, medical devices, and tissue engineering will be also summarized. Finally, the chapter will conclude with a characterization section outlining recent studies focusing on PCL based composites and films.

Yolk-Shell Nanostructures: Syntheses and Applications for Lithium-Ion Battery Anodes

Yolk-shell nanostructures have attracted tremendous research interest due to their physicochemical properties and unique morphological features stemming from a movable core within a hollow shell. The structural potential for tuning inner space is the focal point of the yolk-shell nanostructures in a way that they can solve the long-lasted problem such as volume expansion and deterioration of lithium-ion battery electrodes. This review gives a comprehensive overview of the design, synthesis, and battery anode applications of yolk-shell nanostructures. The synthetic strategies for yolk-shell nanostructures consist of two categories: templating and self-templating methods. While the templating approach is straightforward in a way that the inner void is formed by removing the sacrificial layer, the self-templating methods cover various different strategies including galvanic replacement, Kirkendall effect, Ostwald ripening, partial removal of core, core injection, core contraction, and surface-protected etching. The battery anode applications of yolk-shell nanostructures are discussed by dividing into alloying and conversion types with details on the synthetic strategies. A successful design of yolk-shell nanostructures battery anodes achieved the improved reversible capacity compared to their bare morphologies (e.g., no capacity retention in 300 cycles for Si@C yolk-shell vs. capacity fading in 10 cycles for Si@C core-shell). This review ends with a summary and concluding remark yolk-shell nanostructures.