Nanomedicine Researchers Use Invisible Materials to 'Cloak' Implants

Nanomedicine researchers from UCLA and Northwestern University have teamed up to develop nanoscale polymer thin films that provide efficient localized drug delivery to ‘cloak’ implants, rendering them invisible to the body’s immune system. More specifi cally, these nano-cloaking materials provide potent protection for the implants against the body’s innate defense mechanisms, which can induce implant failure, leading to repetitive surgeries and potential medical complications. By demonstrating their results in vivo through translation of the effi cacy of the novel technology into a mouse model, this study shows the enormous potential and clinical signifi cance of emerging applications in nanomaterials and nanomedicine.

This technology is poised to signifi cantly impact a spectrum of implant-driven medical treatments, as it can be rapidly applied to a broad range of surfaces and can be functionalized with virtually any therapeutic (eg, chemotherapy, anti-infl ammatory, antibiotic) due to the inherent hydrophilic and/or hydrophobic properties that are characteristic of a block copolymer, as well as the drugs with which they are integrated. With implant technologies already serving as a cornerstone of cardiovascular medicine—including stents, pacemakers, and pacing leads—advances in the fi eld have catalyzed the emergence of neural implants to treat Parkinson’s disease, glucose monitors for patients with diabetes, and other applications. Th e cloaking properties of the nanofi lms are expected to facilitate a healthy implanttissue interface, which would ultimately mean a better quality of life for millions of patients worldwide.

In this particular study, the researchers integrated dexamethasone, a clinically relevant anti-infl ammatory, with the block copolymer nanofi lms. The researchers compared tissue collected from animals that did not contain an implant, animal tissue that contained an uncoated implant, and animal tissue that contained a nanocloaked implant. The uncoated implants generated an infl ammatory response in the surrounding tissue that was confi rmed by the study to be mediated by macrophages, which serve as the body’s switch to facilitate the subsequent rejection of the implant and imminent breakdown in its functionality. Tissue from non-implanted mice and nano-cloaked implants looked virtually identical, demonstrating that implant discs coated with the therapeutic nanocloaking hybrid materials were effectively shielded completely from the body’s defenses, signifying the translational signifi cance of the drug-eluting nanofilms.

In addition, the ability to tailor the drug release and potency characteristics of the hybrid nanofi lms was further demonstrated when researchers employed a rapid layer-by-layer fabrication approach known as Langmuir-Blodgett deposition to control the amount of therapeutic that was added to the implant surface. Using this method, the strength of the suppression of infl ammation could be easily controlled, and the researchers opened up an opportunity to develop multi-layered systems with multiple drugs to enable combinatorial drug delivery and control over the sequence of drug delivery, both of which could generate treatment with increased effi ciency. Furthermore, comprehensive genetic testing revealed the innate biocompatibility of the cloaking nanofi lm materials, providing vital confi rmation of their translational potential. The researchers are now pursuing the development of a nanofi lm-based patch device that will provide localized chemotherapy to eliminate system side eff ects associated with conventional systemic delivery methods.

Dr. Ho is an Assistant Professor in the Departments of Biomedical and Mechanical Engineering, a member of the Robert H. Lurie Comprehensive Cancer Center, and the director of the Nanoscale Biotic-Abiotic Systems Engineering Laboratory at Northwestern University.