Cell-based therapies, where naturally or artificially engineered cells secreting therapeutic proteins are grafted onto the body to act as biological drug factories, are an attractive approach for long-term treatment of chronic diseases such as hemophilia, diabetes and liver disorders. However, ‘off the shelf’ therapeutic cells are immunogenic to the host and must be protected from the host immune system. Cell-encapsulation has emerged as an attractive strategy to transplant these cells without chronic immunosuppression. Here, cells are placed in an immune-isolating device which physically separates the cells from the components of the immune system while providing access to oxygen and nutrients. Retrievable macroscale cell- encapsulation devices (macrodevice), are attractive in this context as they provide a safer path to clinical translation. Unfortunately, a standalone macrodevice that remains functional in humans over long-periods (>6 months) is yet to be realized due to two core challenges: 1) a foreign-body reaction to the implanted device causing inflammation and fibrosis, and 2) inadequate supply of oxygen and nutrients to the encapsulated cells. Here, we propose to build on several promising recent advances in biomaterials design, microfabrication, bioelectronics and cell engineering from our team to develop an advanced “smart” macrodevice platform with integrated electronic components which overcomes the major limitations of current device designs. First, we will develop an engineered cell line which is amenable to long term encapsulation and suitable for clinical translation. Landing pads within these cells will ensure stable transgene expression, allowing for broad control of therapeutic protein secretion (Aim 1). Separately, we will develop a bioelectronic macrodevice as a platform for long- term transplant of these cells in vivo. Our device will incorporate novel membranes with uniform/controlled pore-sizes and enhanced oxygen transport properties. In parallel, we will develop new surface coating techniques to minimize fibrosis and ensure long- term graft survival. We will integrate proton exchange membranes and optoelectronic components to allow a) in-situ oxygen generation, and b) optical gene activation to allow for triggerable control of protein production by the encapsulated cells (Aim 2). Finally, we will test the device in B6 mice using a model protein (SEAP) to test for long term survival of cells and external control of protein delivery. We will develop the device as a platform to delivery of Factor VIII for the treatment of Hemophilia A (Aim 3) as a model disease. If successful, the platform will represent a qualitative technological advancement in the field of cell therapy.

Implanted, encapsulated cell therapies represent a promising approach to continuous, long-term treatment of chronic conditions, but are frustrated by several key challenges that include the foreign body response of the host, local hypoxia in the cell microenvironment and lack of continuous control over cell function. Here we will develop biocompatible cell-encapsulating implants with engineered cell lines and advanced bioelectronics to support and modulate cell function in vivo as a long-term therapy for hemophilia. If successful, the resulting technologies will offer qualitative improvements into the standard of care for chronic diseases.