Electrospinning is well thought of as the most potent nanofiber producing technique, which is applicable in biomedical fields. The generation of electrospun nanofibers as drug carriers has widely been shown much interest over the past years. Electrospun nanofibers meet various advantages as drug delivery platforms including high surface area, acceptable mechanical properties based on the choice of the polymer, high processability, and the possibilities for surface modifications. Silk fibroin protein has gained a great attention as a drug delivery carrier due to ease of purification, sterilization, processability without using chemical crosslinkers, good biocompatibility, tailorable biodegradability, low immunogenicity, and high capacity to stabilize the loaded drugs. These characteristics along with advantageous benefits of electrospinning provide opportunities for producing suitable nanofibers based on silk fibroin for drug delivery purposes. It is also possible to incorporate various functional moieties to the electrospun silk fibroin nanofibers to enhance its biological activities. This review covers the progress in electrospinning of silk fibroin as a drug carrier in recent years.Copyright © 2020 Elsevier B.V. All rights reserved.

Targeted delivery of therapeutic agents to malignant tissues is crucial for enhancing clinical outcomes and reducing side effects. Magnetic nanorobots (MNRs) present a promising strategy for controlled delivery, leveraging external magnetic fields to achieve precise in vivo targeting. This work develops elongated MNRs comprising linearly arranged magnetic nanoparticles linked by metal-polyphenol complexes (MPCs) for magnetic-field-directed active tumor targeting and synergistic tumor therapy. The MNRs are created by assembling 30 nm FeO nanoparticles, tannic acid, and ferrous ions (Fe) under a uniform magnetic field, resulting in elongated chain-like structures fixed by MPCs, which also promotes peroxidase-like activity. These structures show a greater magnetic response than individual nanoparticles, offering flexibility in magnetic manipulation. The MPCs coating allows tailored surface modifications with glucose oxidase, copper ions (Cu), and human serum albumin (HSA), producing colloidally stable MNRs with a built-in multienzymatic cascade (MNRs@GOx/Cu/HSA) that consumes glucose, generates OH, and depletes the antioxidant glutathione (GSH). Collectively, surface-engineered multifunctional MNRs demonstrate improved in vivo tumor targeting driven by external magnetic fields, leading to efficient localized chemodynamic therapy. The tailored structural and functional properties of the developed MNRs render them suitable for targeted cargo delivery, minimally invasive surgery, and localized treatments in disease sites.

Excessive biofluid and infection around wounds hinder wound healing. However, conventionally antibacterial wound dressings cannot simultaneously achieve effective biofluid control and intelligent infection treatment, tending to overhydrate wounds and develop drug-resistant bacteria due to the limitations of antibacterial components and material structures. The design of a nanozyme composite cryogel with interconnected macroporous structures, excellent designability, and lower chance of drug-resistance is greatly needed. Herein, Fe-MIL-88NH nanozyme is grafted to glycidyl methacrylate functionalized dialdehyde chitosan Schiff base reaction, and acryloyl Pluronic 127 (PF127-DA) is used as a cross-linking agent to fabricate nanozyme composite cryogels (CSG-M) as a wound dressing to enhance antibacterial and biocompatible performance for biofluid management and wound infection therapy. CSG-M has great hydrophilicity, acid-enhanced positive charge, pH-responsive release, rebinding of nanozymes, and excellent peroxidase and oxidase mimicry activity (generation of OH and O radicals). Notably, due to the negative potential of bacteria, the impact of infection on pH value, and the enzyme-like activity as well as the reversible release of nanozymes influenced by pH, CSG-M can achieve intelligently adaptive trapping and killing of bacteria. CSG-M has enormous potential to be a next-generation wound dressing for biofluid management and bacterial infection treatment in the clinic.

Catheter-associated infections (CAIs) caused by bacterial colonization are significant problems in clinics. Thus, effective antibacterial coatings for biomedical catheters to prevent bacterial infections are urgently needed. Ideal coatings should include the advantage of potent antibacterial properties and being easily and economically modified on the catheter surface. Due to their advantages of adhesive capability on various substrates, an increasing number of coatings based on plant polyphenols have been developed. However, the hydrophilicity of plant polyphenols limits their utilization in coatings. Herein, hydrophobic tannic acid (TA) was synthesized via the one-step electrostatic assembly of TA and benzalkonium chloride (BAC) with the green solvent water as the medium. The as-prepared hydrophobic TA (TBA) facilely formed a stable and colorless coating on the luminal and outer surface of biomedical catheters with broad-spectrum antibacterial activity and biocompatiblity. It was demonstrated that the TBA-coated surfaces displayed excellent bactericidal activity toward Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli), and more than 99% of the above bacteria were killed by the TBA-coated films. The test of the coated catheters in vitro also showed the excellent antibacterial activity of both the outer and luminal surfaces of the catheter. Moreover, in an in vivo mouse model, the coated catheters relatively prevented bacterial colonization compared to the uncoated catheters. Meantime, no significant cytotoxicity and host response for Cell Counting Kit-8 (CCK-8) and tissue compatibility in vivo were observed, indicating the better biocompatibility of the TBA coating. This preparation method overcomes the limitation of the traditional hydrophilic tannic acid as a coating and provides a new method for preventing medical indwelling device-associated infections.

Poly(vinylidene fluoride), PVDF, as one of important polymeric materials with extensively scientific interests and technological applications, shows five crystalline polymorphs with α, β, γ, δ and ε phases obtained by different processing methods. Among them, β phase PVDF presents outstanding electrical characteristics including piezo-, pyro-and ferroelectric properties. These electroactive properties are increasingly important in applications such as energy storage, spin valve devices, biomedicine, sensors and smart scaffolds. This article discusses the basic knowledge and character methods for PVDF fabrication and provides an overview of recent advances on the phase modification and recent applications of the β phase PVDF are reported. This study may provide an insight for the development and utilization for β phase PVDF nanofilms in future electronics.