Helical alignments within the heart’s musculature have been speculated to be important in achieving physiological pumping efficiencies. Testing this possibility is difficult, however, because it is challenging to reproduce the fine spatial features and complex structures of the heart’s musculature using current techniques. Here we report focused rotary jet spinning (FRJS), an additive manufacturing approach that enables rapid fabrication of micro/nanofiber scaffolds with programmable alignments in three-dimensional geometries. Seeding these scaffolds with cardiomyocytes enabled the biofabrication of tissue-engineered ventricles, with helically aligned models displaying more uniform deformations, greater apical shortening, and increased ejection fractions compared with circumferential alignments. The ability of FRJS to control fiber arrangements in three dimensions offers a streamlined approach to fabricating tissues and organs, with this work demonstrating how helical architectures contribute to cardiac performance.

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Historically, fibers are known to be relatively passive materials and are used primarily in textiles. Today, however, fibers with a range of functionalities such as electrical and thermal conductivity, superparamagnetic properties, temperature regulation, energy harvesting, and biomedical capability provide many possibilities. Most man-made fibers today are derived from petroleum, but there is increasing emphasis on making fibers biorenewable. Fibers are also the strongest structural materials available today. Different fiber fabrication technologies, available properties, and some near-term future prospects are discussed.

There is an urgent need to develop biodegradable and nontoxic materials from biopolymers and nature-derived antimicrobials to enhance food safety and quality. In this study, electrospinning was used as a one-step, scalable, green synthesis approach to engineer antimicrobial fibers from zein using nontoxic organic solvents and a cocktail of nature-derived antimicrobials which are all FDA-classified Generally Recognized as Safe (GRAS) for food use. Morphological and physicochemical properties of fibers, as well as the dissolution kinetics of antimicrobials were assessed along with their antimicrobial efficacy using state of the art analytical and microbiological methods. A cocktail of nature-derived antimicrobials was developed and included thyme oil, citric acid, and nisin. Its ability to inactivate a broad-spectrum of with food-related pathogens was demonstrated. Morphological characterization of the electrospun antimicrobial fibers revealed bead-free fibers with a small average diameter of 165 nm, whereas physicochemical characterization showed high surface area-to-volume ratio (specific surface area:21.91 m2/g) and presence of antimicrobial analytes in the fibers. The antimicrobials exhibited initial rapid release from the fibers in 2 h into various food simulants. Furthermore, the antimicrobial fibers effectively reduced E. coli and L. innocua populations by ∼5 logs for after 24 h and 1 h of exposure, respectively. More importantly, due to the small diameter and high surface area-to-volume ratio of the fibers, only miniscule quantities of fiber mass and antimicrobials per surface area (2.50 mg/cm2 of fibers) are needed for pathogen inactivation. The scalability of this fiber synthesis process was also demonstrated using a multineedle injector with production yield up to 1 g/h. This study shows the potential of using nature-derived biopolymers and antimicrobials to synthesize fibers for sustainable food packaging materials.

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