ARAKNIPRINT: 3D Printing of Synthetic Spider Silk to Produce Biocompatible and Resorbable Biomaterials

At $3.07 billion in 2013, the 3D printing industry was projected to reach$12.8 billion in 2018 and exceed $21 billion by 2020 (Wohlers and Caffrey, 2013). A lucrative part of this expanding industry includes printing biocompatible medical implants, devices, and tissue scaffolds. A common problem encountered with traditional devices, implants, and tissue scaffolds is that they are not unique to the patient and lack the necessary strength and biocompatibility. To answer these demands, customizable devices are being produced from patient medical scans and CAD designs using 3D printers. These printers traditionally use thermoplastics because of the ease with which they are printed. These plastics are typically regarded as biocompatible but can degrade to less biocompatible forms in the body and leave the implant site, causing inflammatory and foreign body responses. Because of these problems, there has been a focus on developing new biomaterials for medical 3D printers. Spider silk is a natural protein polymer that is stronger than steel or Kevlar and more elastic than nylon. It has also been shown to be more biocompatible than many materials currently used in 3D printers. In previous animal studies, spider silk has proven to not cause an inflammatory response upon degradation which makes it a desired resorbable implant material (Lewis, 2006). A 3D printer system comprised of a synthetic spider silk resin and a modified 3D printer was developed. A fused filament 3D printer, purchased for under$600, was modified with a custom syringe pump design. This syringe pump allowed for the extrusion of spider silk proteins through a needle, producing defined structures. Cell studies were performed on these structures which showed favorable cell attachment and growth. Capable of entering various emerging industries, spider silk offers an alternative in 3D printed biomaterials

Silkworms with Spider Silklike Fibers Using Synthetic Silkworm Chow Containing Calcium Lignosulfonate, Carbon Nanotubes, and Graphene

Silkworm silk has become increasingly relevant for material applications. However, the industry as a whole is retracting because of problems with mass production. One of the key problems is the inconsistent properties of the silk. A means by which to improve the silk material properties is through enhanced sericulture techniques. One possible technique is altering the feed of the silkworms to include single-wall carbon nanotubes (SWNTs) or graphene (GR). Recently published results have demonstrated substantial improvement in fiber mechanical properties. However, the effect of the surfactant used to incorporate those materials into the feed on the fiber mechanical properties in comparison to normal silkworm silk has not been studied or reported. Thus, the total effect of feeding the SWNT and GR in the presence of surfactants on silkworms is not understood. Our study focuses on the surfactant [calcium lignosulfonate (LGS)] and demonstrates that it alone results in appreciable improvement of mechanical properties in comparison to nontreated silkworm silk. Furthermore, our study demonstrates that mixing the LGS, SWNT, and GR directly into the artificial diet of silkworms yields improved mechanical properties without decline below the control silk at high doses of SWNT or GR. Combined, we present evidence that mixing surfactants, in this case LGS, directly with the diet of silkworms creates a high-quality fiber product that can exceed 1 GPa in tensile strength. With the addition of nanocarbons, either SWNT or GR, the improvement is even greater and consistently surpasses control fibers. However, feeding LGS alone is a more economical and practical choice to consistently improve the mechanical properties of silkworm fiber

Producing Spider Silk Fibers

Millions of years of evolution have turned proteins into incredible biomaterials. Among protein superstars is dragline spider silk. Excreted by spiders as a lifeline, it is the strongest biomaterial known to man. Millions of years of evolution have also made spiders highly independent (in other words; territorial and cannibalistic), which poses major barriers to farming. Genetic engineering has provided an alternative to this problem via production of this protein in other organisms. The focus of this research is optimizing the mechanical spinning of proteins produced by transgenic goats. In order to bring the strength of synthetic fibers up to par with those produced by spiders, testing has been done with varying parameters for this spinning e.g. speed, stretch, temperature, additives, solvents, etc.. In addition to optimizing properties this research plans to design, build, and test spinning systems that integrate these treatments and maximize the speed of silk production for commercial use. The hope is to match the properties of native spider silk in tensile strength and elasticity. The results from previous experiments and plans for future experiments will be presented

Spider Goats: Maximizing Spider-Silk Protein Recovery per Volume of Milk Processed

Spider silk, which is composed of proteins, is the strongest naturally produced fiber known, which is why it is a promising material with many applications. However, spiders are territorial and cannibalistic, traits that make harvesting spider silk difficult. The spider-silk lab at Utah State University has developed methods for synthetically producing spider silk using the spider silk genes in various transgenic hosts. The spider silk genes have been spliced into silk worms, alfalfa, E. coli bacteria, and goats for production of the spider silk protein. The main focus of this research is the goats and their spider silk protein. The goats are specially designed to produce the protein only in their milk, which is then processed and purified for further research projects. The efficiency of the milk production, and therefore the production of the spider silk protein needed to be maximized. This is accomplished in two stages. The first stage is to determine which goats in the herd produce the most milk and the most protein as compared to other goats producing the same protein type. Production is then optimized by carrying the best milk and protein producers to the next generation with any added alterations made to sequences for better protein production. The second stage of maximization occurs in the laboratory and involves the determination of the optimal processing method and time to recover the most protein while allowing for the most milk to be processed. Future plans for further optimization include tagging the spider silk protein for easier recovery and developing different methods to purify the harvested protein. The optimized methods for recovery will then be scaled up to accommodate larger milk processing volumes to keep up with milk production and herd size

Development of a Process for the Spinning of Synthetic Spider Silk

Spider silks have unique mechanical properties but current efforts to duplicate those properties with recombinant proteins have been unsuccessful. This study was designed to develop a single process to spin fibers with excellent and consistent mechanical properties. As-spun fibers produced were brittle, but by stretching the fibers the mechanical properties were greatly improved. A water-dip or water-stretch further increased the strength and elongation of the synthetic spider silk fibers. Given the promising results of the water stretch, a mechanical double-stretch system was developed. Both a methanol/water mixture and an isopropanol/water mixture were independently used to stretch the fibers with this system. It was found that the methanol mixture produced fibers with high tensile strength while the isopropanol mixture produced fibers with high elongation

Importance of Heat and Pressure for Solubilization of Recombinant Spider Silk Proteins in Aqueous Solution

The production of recombinant spider silk proteins continues to be a key area of interest for a number of research groups. Several key obstacles exist in their production as well as in their formulation into useable products. The original reported method to solubilize recombinant spider silk proteins (rSSp) in an aqueous solution involved using microwaves to quickly generate heat and pressure inside of a sealed vial containing rSSp and water. Fibers produced from this system are remarkable in their mechanical ability and demonstrate the ability to be stretched and recover 100 times. The microwave method dissolves the rSSPs with dissolution time increasing with higher molecular weight constructs, increasing concentration of rSSPs, protein type, and salt concentration. It has proven successful in solvating a number of different rSSPs including native-like sequences (MaSp1, MaSp2, piriform, and aggregate) as well as chimeric sequences (FlAS) in varied concentrations that have been spun into fibers and formed into films, foams, sponges, gels, coatings, macro and micro spheres and adhesives. The system is effective but inherently unpredictable and difficult to control. Provided that the materials that can be generated from this method of dissolution are impressive, an alternative means of applying heat and pressure that is controllable and predictable has been developed. Results indicate that there are combinations of heat and pressure (135 °C and 140 psi) that result in maximal dissolution without degrading the recombinant MaSp2 protein tested, and that heat and pressure are the key elements to the method of dissolution

Comparing the Use of a Mobile App and a Web-Based Notification Platform for Surveillance of Adverse Events Following Influenza Immunization: Randomized Controlled Trial

BackgroundVaccine safety surveillance is a core component of vaccine pharmacovigilance. In Canada, active, participant-centered vaccine surveillance is available for influenza vaccines and has been used for COVID-19 vaccines. ObjectiveThe objective of this study is to evaluate the effectiveness and feasibility of using a mobile app for reporting participant-centered seasonal influenza adverse events following immunization (AEFIs) compared to a web-based notification system. MethodsParticipants were randomized to influenza vaccine safety reporting via a mobile app or a web-based notification platform. All participants were invited to complete a user experience survey. ResultsAmong the 2408 randomized participants, 1319 (54%) completed their safety survey 1 week after vaccination, with a higher completion rate among the web-based notification platform users (767/1196, 64%) than among mobile app users (552/1212, 45%; P<.001). Ease-of-use ratings were high for the web-based notification platform users (99% strongly agree or agree) and 88.8% of them strongly agreed or agreed that the system made reporting AEFIs easier. Web-based notification platform users supported the statement that a web-based notification-only approach would make it easier for public health professionals to detect vaccine safety signals (91.4%, agreed or strongly agreed). ConclusionsParticipants in this study were significantly more likely to respond to a web-based safety survey rather than within a mobile app. These results suggest that mobile apps present an additional barrier for use compared to the web-based notification–only approach. Trial RegistrationClinicalTrials.gov NCT05794113; https://clinicaltrials.gov/show/NCT0579411