With their seemingly limitless capacity for self-improvement, stem cells have a wide range of potential uses in the medical field. Stem-cell-secreted extracellular vesicles (EVs), as paracrine components of stem cells, are natural nanoscale particles that transport a variety of biological molecules and facilitate cell-to-cell communication which have been also widely used for targeted drug delivery. These nanocarriers exhibit inherent advantages, such as strong cell or tissue targeting and low immunogenicity, which synthetic nanocarriers lack. However, despite the tremendous therapeutic potential of stem cells and EVs, their further clinical application is still limited by low yield and a lack of standardized isolation and purification protocols. In recent years, inspired by the concept of biomimetics, a new approach to biomimetic nanocarriers for drug delivery has been developed through combining nanotechnology and bioengineering. This article reviews the application of biomimetic nanocarriers derived from stem cells and their EVs in targeted drug delivery and discusses their advantages and challenges in order to stimulate future research.

Three new polyoxypregnane glycosides, tenacigenosides F–H (1–3), were isolated from the stems of Marsdenia tenacissima. The structures of these new compounds were elucidated from 1D and 2D NMR spectra, as well as from HR-MS and acid hydrolysis.

Poly (vinyl alcohol)/β-cyclodextrin (PVA/CD) composite fibers are prepared by wet spinning followed by hot stretching. XRD results show that β-CDs are in an amorphous state in fiber, and β-CD can help maintain the fibrous crystal that exists in the composite fiber. The DSC results show that the total crystalline ratio of the composite fibers decreased with the increase of β-CD. The as-prepared composite fibers were further crosslinked with glutaraldehyde (GA) to improve their usability. The crosslinked structure, together with amorphous β-CD, contributes to the loading and sustained release of fragrance molecules that were studied. The fragrance retention ratio of PVA/CD/GA is 55.63% and 48.25% for cis-jasmone and citronella, even after 25 days. The inclusion complexes of β-CD and fragrance molecules are confirmed by 2D-FTIR, which is responsible for the sustained release of fragrance. This study may contribute to the mass production of wearable long-term scented fabrics.

Organic fluorides are widely used in pharmaceuticals, agrochemicals, material sciences, and other fields due to the special physical and chemical properties of fluorine atoms. The synthesis of alkyl fluorinated compounds bearing multiple contiguous stereogenic centers is the most challenging research area in synthetic chemistry and has received extensive attention from chemists. This review summarized the important research progress in the field over the past decade, including asymmetric electrophilic fluorination and the asymmetric elaboration of fluorinated substrates (such as allylic alkylation reactions, hydrofunctionalization reactions, Mannich addition reactions, Michael addition reactions, aldol addition reactions, and miscellaneous reactions), with an emphasis on synthetic methodologies, substrate scopes, and reaction mechanisms.