Design and Evaluation of Enzyme-Powered Nanobots for Crossing Biological Barriers and Treating Cancer

Meritxell Serra

Samuel Sánchez Ordóñez

Smart Nano-Bio-Device (IBEC)

Nanomedicine has attracted increasing clinical interest in recent decades, which has allowed the approval of numerous products, especially in oncology. This is due to its ability to encapsulate, protect and release drugs selectively, reducing the required doses and side effects. However, nanoparticle-based drug delivery systems have not significantly outperformed traditional treatments in terms of bioavailability. This inefficiency can be attributed to the various physical and biological barriers that nanoparticles must overcome, such as the extracellular matrix or the mucus barrier, which prevent drugs from reaching tumor cells. Therefore, the aim of this thesis is to develop enzymatic nanobots as transporters of therapeutic agents capable of overcoming these barriers in order to improve the efficacy of cancer treatments. In the first project, we established a murine model of bladder cancer and administered urea-propelled nanobots. These nanobots were able to penetrate the extracellular matrix and showed better tumor accumulation compared to passive conditions. Furthermore, treatment with a single administration of radioiodine-labeled nanobots resulted in a 90% reduction in tumor size. Mucus also represents an obstacle to efficient drug delivery. In the second project, we developed catalase nanobots capable of overcoming this barrier. These nanobots are propelled by H2O2, which serves not only as a fuel but also as a mucolytic agent. Using an in vitro model of mucous secretion, we demonstrated a 60% reduction in mucus integrity after treatment with H2O2-propelled nanobots. Similar results were observed in mouse colons ex vivo, where intestinal mucus content decreased by 65% ​​after treatment. By studying the ability to cross the mucus barrier, we demonstrated that nanobots can only overcome it when they combine their mucolytic and motor capabilities. Taking advantage of this knowledge, the third project focused on peritoneal pseudomyxoma, a mucinous carcinoma characterized by cancer cells growing surrounded by mucus. To improve the efficiency of the drug used in clinical practice, we loaded it into nanobots and used them as self-propelled drug delivery systems with mucolytic capabilities. We treated peritoneal pseudomyxoma tumors ex vivo and confirmed that the drug alone cannot cross the mucus and reach the cancer cells. However, the efficacy of the treatment was improved by using H2O2-propelled nanobots loaded with the drug, since the degradation of the mucus combined with the movement of the nanobots facilitates the delivery of the drug. Overall, this thesis highlights the potential of enzymatic nanobots as a versatile platform for cancer treatment. The advances presented here could lead to more effective therapeutic strategies, addressing significant barriers in current treatments and ultimately improving outcomes for oncology patients.

Nanobots Tx S.L. is also interested in incorporating Dr. Serra’s nanobot technology into its pipeline (as outlined in the attached support letter). Once licensed, the company plans to develop the technology through Phase I/II clinical trials. At that stage, opportunities for sublicensing or co-development with partners like Pierre Fabre could provide valuable collaboration or exit strategies.

Nanomedicine; Clinical Interest; Oncology; Drug Encapsulation; Drug Protection; Drug Release; Selective Drug Delivery; Reduced Doses; Side Effects; Bioavailability; Physical Barriers; Biological Barriers; Extracellular Matrix; Mucus Barrier; Tumor Cells; Enzymatic Nanobots; Therapeutic Agents; Cancer Treatment Efficacy; Murine Model; Bladder Cancer; Urea-Propelled Nanobots; Tumor Accumulation; Radioiodine-Labeled Nanobots; Tumor Size Reduction; Catalase Nanobots; Mucus Barrier Overcoming; H₂O₂ Propulsion; Mucolytic Agent; Mucus Integrity Reduction; Intestinal Mucus Content; Mucolytic Capabilities; Motor Capabilities; Peritoneal Pseudomyxoma; Mucinous Carcinoma; Drug Loading; Self-Propelled Drug Delivery Systems; Ex Vivo Tumors; Drug Delivery Improvement; Versatile Platform; Therapeutic Strategies; Oncology Patients.