Progress 07/01/21 to 01/31/23

Outputs
Target Audience: Textile producers and finishers that use DEET and permethrin in their manufacturing procedures and formulations; Companies interested in new biobased insect repellent coatings for prolonged-release on textile substrates; Companies that produce sportwear, outdoor wear, and outdoor recreation structures (e.g., tents); US Department of Defense, military personnel; Bedding/mattress industry Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Our team was able to participate in the Larta Institute's Commercialization Assistance Program for SBIR Phase I Grant Awardees. During this program, we met on numerous occasions with a business development consultant with experience in our field of development to discuss our research, the potential applications of the insect-repellent technology that InsectaPel is developing, and the different potential customer markets and customer segments that we believe our technology would serve. We discussed process to develop a business model and commercialization plan to help us take our technology towards a marketable product. We have discussed potential product revenue models, collaboration partners, barriers to entry, and future capital financing requirements in an attempt to understand the path towards commercialization and to prepare for a potential Phase II application. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Impact Statement: The aim of this project was to develop effective biobased insect repelling latex coating systems for textile applications without the use of synthetic, and potentially harmful, insect repellents. Recent studies by USDA-ARS stated that plant oil-based fatty acids (CFAs) are natural alternatives to the commonly used synthetic insect repellents permethrin and DEET. This project is focused on a new approach to implement different CFA's onto textiles to convey effective and durable insect repellency. The technical goals were aimed to explore effective methods for stabilizing CFAs in polymeric latexes and further coatings on to textile fabrics to repel insects. We investigated and tested different combinations of CFAs, surfactants, and polymer matrices to determine which indicates the most stabilized emulsions while can be effectively applied onto textiles at sufficient levels. We further evaluated insect repellent properties of coated textiles over time. Several identified candidates with excellent insect repellent properties were identified, demonstrating that insect repellent properties of coated textiles were maintained for three weeks. Our biobased insect repellent coatings may open a new insightto producing safer, cost effective, easier to apply, and compliant with EPA insect repellent products in comparison with permethrin and DEET. Objective 1-Entrap repellents in formulae produced for textile coatings: The aim of this task was to explore emulsion polymerization as a feasible process to produce polymeric latexes containing CFAs macro-molecules. Our experiments on the emulsion polymerization of polymer lattices revealed that addition of CFAs in the reaction systems containing nonionic and anionic surfactants inhibited the polymerization. It was due to the fact that CFA's caused acidification and consequently destabilization of the emulsion and phase separation. To prevent the acidifying effects of CFAs, we evaluated the potential use of their amine salts on the emulsion polymerization. Two batches containing the amine salts showed stable formulae and were further considered for the next steps. Objective 2 - Find the maximum achievable load of repellents and tailor the coating formulae to meet requirements for the application: The goal of this task was to develop other batches to stabilize CFAs in polymeric latex systems that could be applied on textile fabrics to provide safe insect repellency without the use of harmful synthetic repellents. Producing fatty acid incorporated stable emulsions was one of the primary challenges in our preliminary studies for textile coating applications. To overcome this hurdle, we initially examined emulsification of CFAs in water solutions in conjunction with several cationic surfactants analyzing 27 batches. A cationic surfactant exhibited the highest emulsion stability among others due to electrostatic. Through this testing, multiple stable formulae for coating applications were identified for further testing. Objective 3 - Use the formulae, with entrapped repellents, for textile coatings: We applied coating batches with maximum amount loadingof active ingredient CFAs onto treated textiles. Ripstop nylon/cottonfabric was used as a substrate for coating purposes and further determination. Conducted tests on different formulations which used CFAs, surfactants and a biomacromolecule as a coating matrix.To apply the coating formulae, textile samples were dipped/bathed in different emulsification bath formulations, then passed through laboratory-based padding and squeezing machine, then dried and cured in laboratory oven at fixed temperature. This application methodology was similarly employed to apply on textiles with different CFA coating formulations. We also prepared a reference sample containing permethrin as an active synthetic insect repellent ingredient to compare with samples embedded with CFAs. Objective 4 - Determine the escapability of repellents from within the coated/treated fabric: We conducted Attenuated total reflection (ATR) spectroscopy to evaluate the chemical properties of textiles after coating. Results from samples showed that CFAs were successfully loaded on fabric samples. In addition, we assessed samples with thermal gravimetric analysis (TGA) after treatment with colloidal solutions containing CFAs, surfactants and coating matrix. Three thermal degradation regions of initial, main, and char decomposition were observed. In the first stage, the weight loss of fabrics was from moisture release, while the main thermal degradation occurred in the second region, where the weight loss was significant. Releasing CFAs from fabric samples was observed in this region resulting in more weight loss of fabrics. We also observed more char content for the fabric containing CFAs. The increased rate of textile weight loss containing CFAs correlated to thermal degradation of CFAs from the coating. We concluded from TGA results that we successfully loaded fatty acids on the fabric samples. Objective 5 - Determine the efficacy of the fabrics infused with biobased repellents in field-testing on insects at the USDA's Agricultural Research Service (ARS): Insect repellent properties of four fatty acid treated fabric samples produced in this study in comparison with Catnip oil (biobased insect repellent) and permethrin (synthetic insect repellent) treated fabrics were assessed. Repellency is determined by percentage of adult stable flies that were observed to have fed on blood through treated fabrics versus fed through controls. Stable flies used for repellency tests were from colonies maintained at ARS's Agroecosystem Management Research Unit. The flies were maintained under standard conditions for testing and fed with citrated bovine blood by soaking feminine napkin in blood and placing atop the cage. Adult flies were fed with blood once, then starved, with water provided for 24-48 hours before repellency test began. Repellent assays were conducted daily at room temperature for at least 2 hours. Flies in the repellent bioassay were exposed to randomized treatments (different repellents and ages), and repeated until at least 15-20 replicated flies were completed. Aging studies/longevity tests of treated fabrics were conducted by removing them from the vacuum sealed bags and hanging on a metal frame for exposure from day-0 (freshly removed the same day as testing day), day-1, day-2, .... up to 3 weeks under laboratory conditions as described above for the bioassay. All those aged fabrics were tested the same as described above. Results: 3 of the CFA-treated samples demonstrated 100% insect repellency, similar to Catnip oil and permethrin treated fabrics. In addition, one sample showed excellent insect repellency. We also exposed these four samples to an open room and ambient temperature environment to evaluate the effect of aging on insect repellent properties. Results demonstrate aging from 1 to 21 days with no negative effects on the insect repellent properties of these CFA-loaded samples. Developed coating formulation could maintain the CFAs as volatile insect repellents even after exposure to the environment without any reduction in the insect repellency. Accordingly, 100% insect repellency was observed on these samples after exposure to an open room environment for 21 days.

Publications

Progress 07/01/21 to 06/30/22

Outputs
Target Audience: Textile producers and finishers that work with DEET and permethrin-impregnated fabrics; Companies interested in new biobased alternatives for prolonged-release insect repellent coatings; Companies that produce sportswear, outdoor wear, and outdoor recreation structures (e.g., tents); US Department of Defense, military personnel; Bedding/mattress industry. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Our team was able to participate in the Larta Institute'sCommercialization Assistance Program for SBIR Phase I Grant Awardees. During this program, we met on numerous occasions with a business development consultant with experience in our field of development to discuss our research, the potential applications of the insect-repellent technology that InsectaPel is developing, and the different potential customer markets and customer segments that we believe our technology would serve. We discussed process to develop a business model and commercialization plan to help us take our technology towards a marketable product. We have discussed potential product revenue models, collaboration partners, barriers to entry, and future capital financing requirements in an attempt to understand the path towards commercialization and to prepare for a potential Phase II application. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We plan on utilizing gas chromatography-mass spectroscopy to analyze and identify the different active substances contained in the CFA coated textiles. For this purpose, we willextract CFAs and other catalyst and surfactant coating materials from subject textile samples using specific solvents. The extracted materials will be further quantified using known reference standards, with goal of further understanding relationship between the different chemical compounds and their potential impact on overall conveyed repellency. Will send additional CFA-impregnated fabric samples onto USDA ARS for additional insect repellency testing. Continue to evaluate and modify CFA application foramulas with goal of increasing durability and longevity of repellency effect.

Impacts
What was accomplished under these goals? Impact Statement:The goal of this project is to develop latex coating systems that enable the manufacture of effective insect repelling fabrics without the use of synthetic, and potentially harmful, insect repellents. USDA ARS has recently shown that plant oil-based fatty acids (CFAs) can be used as natural alternatives to the commonly used synthetic chemical repellents permethrin and DEET. This research is focused on ways to apply these CFA's to textiles to convey effective and durable insect repellency to the textiles.The technical goals are aimed at developing methods for embedding the subject CFAs into polymeric coatings which are suitable for applying to textile fabrics to repel insects. Our approach investigated and tested different combinations of CFAs, surfactants, and polymer matrixes to determine which are the most effective at coating textiles with insect repellent chemistries, with "effective" meaning the active CFA ingredients are carried on the fabric at sufficient levels to have effective repellency and are also durable over time.We have identified three excellent candidates for further study, with additional testing demonstrating insect repellency of textiles being maintained for three weeks after the coating process. Our biobased insect repellent may open a new pathway to producing a repellent that is safer, more cost-effective, easier to apply, and compliant with EPA and related standards in comparison with permethrin for textile coating applications. Objective 1-Entrap repellents in formulae produced for textile coatings:Conductedexperiments on the emulsification of target CFAs which revealed that nonionic and anionic surfactants are not able sufficiently emulsify and stabilize CFAs in the textile coating formulation.However, through additional test runs, were able to identify a cationic surfactant which could interact with, and encapsulate the CFAs resulting in stabilized textile coating formulation. This testing involved producing and analyzing twenty-seven (27) different combinations of CFA, catalyst, and surfactants inbiobased polymeric latexes to determine most stable emulsification of CFAs. Through this testing, multiple stable formulae for coating applications were identified for further testing. Objective 2 - Find the maximum achievable load of repellents and tailor the coating formulae to meet requirements for the application:Seeking to determine which formulations would lend themselves to loading maximum amount of active ingredient CFAs onto treated textiles.A beige Ripstop nylon/cotton (50/50) fabric was used as a substrate for coating applications and testing.Conducted tests on different formulations which used constant CFA and surfactant composition and ratios, butwith varying additive compositions in final biobased coating formulation. Each of these formulations would then be analyzed via thermal gravimetric analysis (TGA) of samples to measureapproximate loading of CFAs onto treated textiles.Testing ofdifferent sample formulations demonstrated the ability to load active ingredient CFAs onto textiles in 10%-15% range with stability. Objective 3 - Use the formulae, with entrapped repellents, for textile coatings:To apply the coating formulae to samples, textile samples weredipped/bathed in different emulsification bathformulations, then passedthrough laboratory-based padding and squeezing machine, then dried and cured in laboratory oven at fixed temperature. This application methodology was employed to apply different CFA textile coating formulationsto multiple textiles samples for testing.Also prepared a textile sample containing permethrin as an active synthetic insect repellent ingredient to compare with samples embedded with CFAs. Objective 4 - Determine the escapability of repellents from within the coated/treated fabric:Tested CFA-loaded textiles via TGA to analyze rate of CFA release. Analyzed textile sample that had been treated with only emulsification formula (surfactant and catalyst, but no CFA)and textile sample treated with same emulsification formula and CFA active ingredient.By comparing the differences in thermal degradation/weight loss of textile without CFA versus textile with CFA, were able to determine that CFA had beensuccessfully loaded onto the fabric, and subsequently released as textile sample was subject to increasing temperature over time. The increased rate of textile weight loss experienced with the CFA treated textile at a certain point during heating cycle, versus that of the non-CFA treated textile, correspondedto the range where fatty acids would be thermally degraded from the coating.We concluded from TGA results that we successfully loaded fatty acids on the fabric samples. Objective 5 - Determine the efficacy of the fabrics infused with biobased repellents in field-testing on insects at the USDA's Agricultural Research Service (ARS):Four (4) developed CFA-impregnated textile samples, one (1) catalyst-only treated textile sample, and one (1) permethrin-impregnated textile sample were sent to ARS for insect repellency testing. Repellency is determined by percentage of adult stable flies that were observed to have fed on blood through treated fabrics versus fed through controls. Stable flies used for repellency tests were from colonies maintained at ARS's Agroecosystem Management Research Unit. The flies were maintained under standard conditions for testing and fed with citrated bovine blood by soaking feminine napkin in blood and placing atop the cage. Adult flies were fed with blood once, then starved, with water provided for 24-48 hours before repellency test began. On day of test, swaths of developed repellent impregnated fabrics were cut to cover wells of testing module. When testing, pads were soaked with ~3.5 mL of citrated bovine blood. Blank fabric used as the control and catnip oil as a positive control as catnip oil reported as the strongest feeding deterrent against stable flies.Approximately 3-5 starved flies were collected from the fly cages and transferred into each testing cell. After 2 hours, tested stable flies were checked for feeding status by rupturing their abdomen to determine the presence of blood after the trials. Repellent assays were conducted daily at room temperature for at least 2 hours. Flies in the repellent bioassay were exposed to randomized treatments (different repellents and ages), and repeated until at least 15-20 replicated flies were completed. Replicate numbers were determined by the number of treatments tested per day, and controls were always run simultaneously. Aging studies/longevity tests of treated fabrics were conducted by removing them from the vacuumsealed bags and hanging on a metal frame for exposure from day-0 (freshly removed the same day as testing day), day-1, day-2, .... up to 3 weeks under laboratory conditions as described above for the bioassay. All those aged fabrics were tested the same as described above. Insect repellent properties of different fatty acid treated fabric samples produced in this study in comparison with Catnip oil (biobased insect repellent) and permethrin (synthetic insect repellent) treated fabrics were assessed. Results: 3 of the CFA-treated samples demonstrated 100% insect repellency, similar to Catnip oil and permethrin treated fabrics. We also exposed samples to an open room and ambient temperature environment to evaluate the effect of aging on insect repellent properties. Results demonstrate aging from 1 to 21 days with no negative effects on the insect repellent properties of these CFA-loaded samples. Developed coating formulation could maintain the CFAsas volatile fatty acids even after exposure to the environment without any reduction in the insect repellency. Accordingly, 100% insect repellency was observed on these samples after exposure to an open room environment for 21 days.

Publications