No abstract

Nanoparticles (NPs) are referred to as tiny materials in size ranging from 1 to 100 nm. Unique characteristics of the NPs, including small sizes and high surface area, appropriate reactivity, proper stability, great strength, and many more, have resulted in their wide use in numerous fields. Among different techniques reported for synthesizing the nanoparticles, electro-hydrodynamic atomization or electrospray has been identified as a well-practiced and high efficient technique for the formation of fine and homogenous NPs from a liquid under the influence of electrical forces. This process allows feasible encapsulation of different drugs, vitamins, and proteins applicable in the targeted drug delivery systems. Since the release rate of the loaded pharmaceutical materials could be easily tuned via varying the properties of core and shell components. Herein, we summarized the importance of the electrospray technique for the production of drug-loaded nanoparticles applicable in controlled drug delivery systems.

Electrospraying (electrohydrodynamic spraying) is a method of liquid atomization by electrical forces. Spraying solutions or suspensions allow production of fine particles, down to nanometer size. These particles are interesting for a wide variety of applications, thanks to their unprecedented chemical and physical behaviour in comparison to their bulk form. Knowledge of the particle size in powders is important in many studies employing nanoparticles. In this paper, the effect of some process parameters on the size of electrosprayed polyacrylonitrile particles is presented in the form of response surface model. The model is achieved by employing a factorial design to evaluate the influence of parameters on the polyacrylonitrile nanoparticle size and response surface methodology. Four electrospraying parameters, namely, applied voltage, electrospraying solution concentration, flow rate, and syringe needle diameter were considered.

Appropriate mechanical properties in both longitudinal and circumferential directions are an important requirement for the scaffold aimed at tissue engineering of the human urinary bladder. In this research, three weft-knitted silk fibroin scaffolds with stitch densities of 138, 182, and 245 loops/cm 2 were fabricated and studied for potential use in bladder regeneration applications. It was shown that the porosity and surface porosity of the scaffolds increased as stitch density decreased. Moreover, increasing the stitch density assisted with decreasing the very big pore size of the weft-knitted scaffolds. The uniaxial mechanical properties of the degummed scaffolds (namely strength and loading-unloading behavior), as well as multiaxial mechanical properties (providing the clinically relevant assessment conditions), were studied. We further studied the effect of cell culturing on the uniaxial mechanical properties of the scaffolds. It was observed that the cell-cultured scaffold represented more strength and strain than the control scaffold after 6 weeks in culture. This study demonstrated that all three studied scaffolds demonstrate low stiffness (high compliance) along with high strength and high strains. Furthermore, comparing the uniaxial properties of weft-knitted scaffolds with those of porcine bladder confirms that all three types of silk fibroin weft-knitted scaffolds resemble bladder. However, the scaffold with a stitch density of 182 loops/cm 2 more closely simulated the porcine bladder, which is believed to be similar to the human bladder. Therefore, this scaffold can be a potential candidate for bladder tissue engineering studies.

Orthopedics has been identified as a major clinical medicine branch since the 18th century for musculoskeletal disease diagnosis and therapeutics. Along with technological progress, the surgical treatment of bone disorders became available in the 19th century, while its growth faced several obstacles due to a lack of proper biocompatible material and alternative structures. Therefore, tissue engineering has emerged as a key building block to overcome these challenges, providing the capability for bone growth, and fabricating scaffolds with enriched desirable cellular compatibility as well as mechanical properties. Among various structures, the electrospun layer has implied high porosity and fine pore sizes, and succeeded in cell growth and proliferation. Collagen nanofibers have represented a wide potential for mineralization, bone regeneration, and forming processes. Despite this, such scaffolds have accosted bone remodeling limitations due to inadequate osteoinductivity and mechanical strength. Hence, the tendency to fabricate efficient collagen-based nanofibrous layers enriched with organic and inorganic materials has been extensively declared. Embedding these materials leads to engineering a membrane with appropriate physical, degradability, and mechanical properties, as well as proper mineralization and biological activity required for better replicating the bone organ’s natural microenvironment. This paper highlighted a wide overview of the natural resources, electrospinning strategies, and collagen-based electrospun composites for bone regeneration. Accordingly, future prospects could be developed for generating novel 3D-scaffold formations, benefiting from organic and inorganic substances to boost the biological and mechanical properties, simultaneously.