Recent Progress in Stimuli-Responsive Antimicrobial Electrospun Nanofibers.

Electrospun nanofibrous membranes have garnered significant attention in antimicrobial applications, owing to their intricate three-dimensional network that confers an interconnected porous structure, high specific surface area, and tunable physicochemical properties, as well as their notable capacity for loading and sustained release of antimicrobial agents. Tailoring polymer or hybrid-based nanofibrous membranes with stimuli-responsive characteristics further enhances their versatility, enabling them to exhibit broad-spectrum or specific activity against diverse microorganisms. In this review, we elucidate the pivotal advancements achieved in the realm of stimuli-responsive antimicrobial electrospun nanofibers operating by light, temperature, pH, humidity, and electric field, among others. We provide a concise introduction to the strategies employed to design smart electrospun nanofibers with antimicrobial properties. The core section of our review spotlights recent progress in electrospun nanofiber-based systems triggered by single- and multi-stimuli. Within each stimulus category, we explore recent examples of nanofibers based on different polymers and antimicrobial agents. Finally, we delve into the constraints and future directions of stimuli-responsive nanofibrous materials, paving the way for their wider application spectrum and catalyzing progress toward industrial utilization.

Polycaprolactone nanofiber mats decorated with photoresponsive nanogels and silver nanoparticles: Slow release for antibacterial control.

Smart nanomaterials activated by light is one of the most exciting strategies to control the release of substances in varied environments. Here we developed a smart nanomaterial composed by a photoresponsive nanogel containing silver nanoparticles (AgNps) immobilized on the surface of biodegradable and biocompatible polycaprolactone (PCL) nanofibers mats produced by electrospinning. The AgNps are released from the nanogel and dispersed inside the nanofiber mats when this system is irradiated by light at 405 nm. This light excites the plasmonic band of the AgNps, which breaks the nanogel and, as a consequence, releases the AgNps on the nanofibers. Consequently, this AgNps release mechanism controls the propagation of silver ions by the application of light. Different configurations of antibacterial nanofibers mats, including neat PCL nanofibers and PCL nanofibers modified with AgNps-Nanogels and AgNps, excited by laser light at 405 nm, were investigated regarding antibacterial properties. The best result was achieved using PCL nanofiber mats functionalized with AgNps and AgNps-Nanogels after light exposure, which generated inhibition diameters of 2.6 ±â€¯0.3 mm and 1.8 ±â€¯0.5 mm for S. aureus and E. coli, respectively. The smart nanomaterial developed here is a promising material for clinical application as wound dressing activated by light.

Controlled Release of Silver Nanoparticles Contained in Photoresponsive Nanogels.

Smart nanomaterials can selectively respond to a stimulus and consequently be activated in specific conditions, as a result of their interaction with electromagnetic radiation, biomolecules, or pH change. These nanomaterials are produced through distinct routes and can be used in artificial skin, drug delivery, and other biomedical applications. Here, we report on the fabrication of an antibacterial nanogel formed by aniline- and chitosan-containing silver nanoparticles (AgNp's), with an average size of 78 ± 19 nm. The AgNp nanogel release was triggered by light at 405 nm. Specifically, the electronic energy vibration resulting from the interaction of the irradiation with the AgNp surface plasmon breaks the hydrogen bonds of the nanogels and releases AgNp's. To understand the perturbation of AgNp-nanogels against bacteria, membrane model studies were performed using the main components of the cell membrane of Escherichia coli (E. coli), 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG) and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE). DPPG has more influence on the incorporation of the nanoparticles on the cell membrane due to the electrostatic interaction between the nanoparticle surface and lipid charged groups. The results indicate new possibilities for designing smart antibacterial photoresponsive nanogels with enhanced optical and antibacterial properties to increase E. coli death.