Prolonging the duration of drug action and reducing toxicity play a vital role in wound administration as they reduce the chance of infection and decrease complications and cost. This study reports the natural antioxidant procyanidins extracted from sea buckthorn (SBT) and laboratory-manufactured Apocynum venetum cellulose nanofiber as core drugs. The sustained-release nanofiber membrane was prepared by electrospinning on polylactic acid/polyvinyl pyrrolidone nanofibers. High-performance liquid chromatography-mass spectrometry was used to identify the phenolic compounds in SBT extracts and confirmed the presence of procyanidins with a content of 0.0345 mg/g. The nanofiber membrane was characterized through transmission electron microscopy, encapsulation efficiency, in vitro drug-release study and antioxidant assay. The results indicated that the extracted procyanidins were successfully encapsulated in the core–sheath structure nanofibers, and the encapsulation efficiency of nanofiber membranes reached 83.84%. In vitro measurements of the delivery showed this core–sheath structure could significantly alleviate the drug burst release, which is followed by a linear and smooth release within 30 hours. Further tests showed that the removal efficiency of 2,2-diphenyl-1-picrylhydrazyl reached 88.62%, indicating that the membranes had high antioxidant activity. This work implies that the combination of Apocynum venetum nanocellulose and emulsion electrospun fibers has promising potential applications in tissue engineering or drug delivery.

As new bio-based sustainable materials, this paper made a comparative study on the phloem and straw of Apocynum venetum. The cellulose nanofibers (CNFs) of Apocynum venetum phloem and straw were prepared by the acid hydrolysis method, and then different parts and proportions of poly (lactic acid) (PLA)/CNF films were prepared via electrospinning, respectively. The results revealed the CNF with longer length and finer diameter network structure can be separated by straw, while the short nanostructure of the rod-like structure can be separated by phloem. It was also shown that the wettability and permeability of PLA improved significantly by adding these two kinds of CNFs, the water contact angle of PLA decreased from 130° to 101° and the permeability was up to 4658 g/(m2•d). As for antibacterial properties, the antibacterial rate of CNF from straw proved slightly better than that from phloem against E.coli, reaching more than 90%. It proved that the CNF from straw showed excellent performance as phloem, providing a novel material for the preparation of CNFs, which can be naturally antibacterial and environment-friendly. The obtained PLA/CNF films could be potentially applied in antibacterial medical dressings.

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