Poloxamer: A versatile tri-block copolymer for biomedical applications.

Poloxamers, also called Pluronic, belong to a unique class of synthetic tri-block copolymers containing central hydrophobic chains of poly(propylene oxide) sandwiched between two hydrophilic chains of poly(ethylene oxide). Some chemical characteristics of poloxamers such as temperature-dependent self-assembly and thermo-reversible behavior along with biocompatibility and physiochemical properties make poloxamer-based biomaterials promising candidates for biomedical application such as tissue engineering and drug delivery. The microstructure, bioactivity, and mechanical properties of poloxamers can be tailored to mimic the behavior of various types of tissues. Moreover, their amphiphilic nature and the potential to self-assemble into the micelles make them promising drug carriers with the ability to improve the drug availability to make cancer cells more vulnerable to drugs. Poloxamers are also used for the modification of hydrophobic tissue-engineered constructs. This article collects the recent advances in design and application of poloxamer-based biomaterials in tissue engineering, drug/gene delivery, theranostic devices, and bioinks for 3D printing. STATEMENT OF SIGNIFICANCE: Poloxamers, also called Pluronic, belong to a unique class of synthetic tri-block copolymers containing central hydrophobic chains of poly(propylene oxide) sandwiched between two hydrophilic chains of poly(ethylene oxide). The microstructure, bioactivity, and mechanical properties of poloxamers can be tailored to mimic the behavior of various types of tissues. Moreover, their amphiphilic nature and the potential to self-assemble into the micelles make them promising drug carriers with the ability to improve the drug availability to make cancer cells more vulnerable to drugs. However, no reports have systematically reviewed the critical role of poloxamer for biomedical applications. Research on poloxamers is growing today opening new scenarios that expand the potential of these biomaterials from "traditional" treatments to a new era of tissue engineering. To the best of our knowledge, this is the first review article in which such issue is systematically reviewed and critically discussed in the light of the existing literature.

Tissue engineering with electrospun electro-responsive chitosan-aniline oligomer/polyvinyl alcohol.

Mimicking the native tissue is an ultimate goal in tissue engineering. In this study, conductive chitosan was synthesized by coupling with aniline oligomers, and then conductive nanofibers were fabricated using electrospinning technique to mimic the tissue structure and properties. The conductivity of the resulting biomaterial was adjusted to ca. 10-5 S/cm, which can recapitulate electrical properties of the tissue. The structure of nanofiber was evaluated using scanning electron microscopy noticing that the aniline oligomer addition to the system decreased the diameter of the nanofiber because of its hydrophobic nature. Conductive nanofiber exhibited on-demand drug release feature of the conductive webs, signaled by 40% rise in the drug release at 40 min after electrical stimulation in comparison with non-stimulated webs, characteristic of a promising drug release platform. Moreover, biocompatibility evaluation using MTT assay revealed that the conductive substrate provides a higher cellular activity to the platform with respect to non-conductive substrates. Such platforms are the harbingers of the emerging new generation, which can revolutionize the tissue engineering satisfying an enhanced tissue regeneration.