The world’s first microneedling drug delivery technique for plants

Researchers from the Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP) interdisciplinary research group of the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, and their collaborators from the Temasek Life Sciences Laboratory (TLL) and The Massachusetts Institute of Technology (MIT), developed the first microneedle drug delivery technique for plants.

The method can be used to precisely deliver controlled amounts of agrochemicals to specific plant tissues for research purposes. When applied in the field, it could be used in precision agriculture to improve crop quality and manage diseases.

Increasing environmental conditions caused by climate change, an ever-increasing human population, a lack of arable land and limited resources are pushing the agricultural industry to adopt more sustainable and precise practices that encourage more efficient use of resources (e.g. water, fertilizers and pesticides) and the mitigation of environmental impacts. Developing delivery systems that effectively deploy agrochemicals such as micronutrients, pesticides and antibiotics to crops will help ensure high productivity and high quality products, while minimizing resource wastage is crucial.

However, current and standard practices for agrochemical application to plants, such as foliar spraying, are ineffective due to off-target application, rapid runoff in rain, and rapid degradation of active substances. These practices also cause significant adverse environmental side effects such as water and soil contamination, loss of biodiversity and degraded ecosystems. and public health concerns such as respiratory problems, chemical exposure, and food contamination.

The new silk-based microneedles technique developed by SMART overcomes these limitations by deploying and targeting a known amount of payload directly into the deep tissues of a plant, which will lead to higher plant growth efficiency and aid in disease management. The technique is minimally invasive as it delivers the compound without causing long-term damage to plants and is environmentally sustainable. It minimizes the wastage of resources and mitigates the adverse side effects caused by agrochemical pollution of the environment. In addition, it will help promote precision agricultural practices and provide new tools for studying plants and designing crop traits, helping to ensure food security.

It is described in a paper titled “Plant Drug Delivery Using Silk Microneedles,” published in the January 2023 issue of Advanced Materials, the research studies the first polymeric microneedles used to deliver small compounds to a wide variety of plants and the plants’ response to biomaterial injection. Through gene expression analysis, researchers could closely examine responses to drug administration after microneedle injection. Minimal scarring and callus formation was observed, indicating minimal injury to the plant caused by the injection. The proof of concept provided in this study opens the door to the application of plant microneedles in plant biology and agriculture, enabling new means of modulating plant physiology and studying metabolism through effective and efficient delivery of payloads.

The study optimized the design of microneedles to target the systemic transport system in Arabidopsis (mouse-cress), the selected model plant. Gibberellic acid (GA3), a widely used plant growth regulator in agriculture, was selected for delivery. The researchers found that microneedling administration of GA3 was more effective in promoting growth than traditional methods (such as foliar spraying). They then confirmed the effectiveness using genetic methods and demonstrated that the technique is applicable to a variety of plant species, including vegetables, cereals, soybeans and rice.

Professor Benedetto Marelli, co-author of the paper, Principal Investigator at DiSTAP, and Associate Professor of Civil and Environmental Engineering at MIT, shared, “The technique saves resources compared to current agrochemical delivery methods, which suffer from waste. application, the microneedles penetrate tissue barriers and release compounds directly into the plants, avoiding agrochemical losses. The technique also allows precise control of the amounts of agrochemical used, ensuring high-tech precision agriculture and crop development to optimize yield.”

“The first-of-its-kind technique is revolutionary for the agriculture industry. It also minimizes resource waste and environmental pollution. In the future, with the ability to automatically apply microneedles, the technique can be used in outdoor and indoor high-tech farms for precise agrochemical delivery and disease management,” added Dr. Yunteng Cao, the paper’s first author and a Postdoctoral Fellow in Civil and Environmental Engineering at MIT.

“This work also highlights the importance of using genetic tools to study plant responses to biomaterials. Analyzing these responses at the genetic level offers a comprehensive understanding of these responses, thus serving as a guide for the development of future biomaterials that can be used in the AgriFood Industry,” said Sally Koh, the first author of this paper and a Ph.D. candidate from the National University of Singapore (NUS) and TLL.

The future looks promising as Professor Daisuke Urano, co-corresponding author of the paper, TLL Principal Investigator and NUS Adjunct Assistant Professor elaborated, “Our research has validated the use of silk-based microneedles for agrochemical application and we look forward to further development the microneedle technique and design into a scalable model for manufacturing and commercialization. At the same time, we are also actively researching potential applications that could have a significant impact on society.”