INTRODUCTION

Cell replacement therapy has seen unprecedented progress in the past few years, including the ability to achieve insulin independence in humans through islet transplantation (Atkinson et al.,Lancet2014, 383, 69-82; Orlando et al.,Diabetes2014, 63, 1433-1444; Hatziavramidis et al.,Ann. Biomed. Eng.2013, 41, 469-476). Advancements in stem cell technology hold potential to overcome donor shortages for many patients, who can benefit from islet replacement therapy. In particular, stem-cell-derived beta cells offer a promising new cell source for achieving insulin independence. Unfortunately, life-long systemic immunosuppression is required to protect transplanted cells from being rejected putting patients at risk of organ damage, infection and malignancies (Ludwig et al.,Proc. Natl. Acad. Sci. U.S.A2013, 110, 19054-19058; Shapiro et al.,N. Engl. J. Med.2000, 343, 230-238). Cell encapsulation provides an alternative approach to protect transplanted cells without the complications associated with immunosuppression. While a number of strategies are being investigated (Huang et al.,PLoS One2013, 8; Shah,Biomatter2013, 3, 1-7; Song et al.,Mater. Sci. Eng. C. Mater. Biol. Appl.2014, 40, 197-203; De Faveri et al.,Neuroeng.2014, 7, 7; Robles et al.,Cell Transplant.2013; Tomei et al.,Proc. Natl. Acad. Sci. U.S.A2014, 111, 10514-10519), there are several challenges associated with these approaches: retrievability, control over pore dimensions, biocompatibility, scalability, and reproducible fabrication methods.

The key function of an encapsulation device is to create an environment that allows for normal insulin secretion in response to fluctuating blood glucose, while maintaining cell viability through sequestration from the immune system and effective nutrient and waste exchange. With the goal of creating immune-protected beta cells, a variety of micro- and macro-encapsulating approaches have been developed over the past several decades (Scharp et al.,Adv. Drug Deliv. Rev.2014, 67-68, 35-73; Weir,Diabetologia2013, 56, 1458-1461; Buder et al.,Immune Netw.2013, 13, 235-239, Julien et al.,Fontiers Biosci. (Landmark Ed.) 2014, 19, 49-76). The fundamental distinction between micro- and macro-devices is a matter of scale: micro-encapsulation approaches encapsulate a single cell or islet, which maximizes surface area to volume ratios and promotes improved nutrient exchange (Cala et al., Clinical Application of Microencapsulated Islets: Actual Prospectives on Progress and Challenges. 2014, 68, 84-92; Cornolti et al.,Cell2009, 18, 195-201). However, there is limited control of membrane thickness and pore size with micro-encapsulation.

Additionally, since islets are individually encapsulated, thousands of microdevices are required for each transplant, and capsule size makes live imaging and tracking a significant challenge. Conversely, macro-encapsulation devices house many cells or islets (Lathuilière et al.,Biomaterials2014, 35, 779-791). These larger devices allow for greater control over membrane parameters, such as pore size and porosity, but are plagued by limited nutrient diffusion and cell response due to the device thickness and large device reservoir. In addition to these challenges, the sharp rigid structures typically associated with macro-encapsulation devices can lead to a foreign body response and subsequent device failure from fibrotic encapsulation (Ward,J. Diabetes Sci. Technol.2008, 2, 768-777; Ward et al.,Biomaterials2002, 23, 4185-4192).

The present disclosure address these as well as other needs in the field of delivery of biological material to a subject in need thereof.

SUMMARY

Thin film devices that encapsulate cells for transplantation of the cells into a subject are provided. Also provided are methods of preparing the subject devices and methods for using the subject devices. The thin film devices include a first layer, a population of cells and a second layer, where the first layer and the second layer are in contact with one another around the periphery of the cells disposed between the first layer and the second layer. The thin film medical devices are used in methods for providing encapsulated transplanted cells in a subject. The method includes transplanting the thin film device into a subject; promoting vascularization of the device and/or; inhibiting foreign body response and/or; limiting ingress of cytokines, immunoglobulins and cells into the device; and releasing molecules secreted by the encapsulated cells.

In certain embodiments, a method for transplanting cells in a subject is disclosed. The method may include: (a) providing a thin film device comprising: (i) a first nanoporous or microporous polymer layer; (ii) a second nanoporous or microporous polymer layer, wherein the first and second layers define a lumen between the first and second layers; and (iii) a population of cells disposed in the lumen between the first and second layers, wherein first and second polymer layers are each less than 15 μm thick, and the device has a surface area of 1 cm2to 5 cm2, (b) transplanting the device into a subject, wherein one or more of: (i) vascularization into the lumen of the device via the pores in the first polymer layer and/or second polymer layer; (ii) a limited foreign body response to the device; (iii) a limited ingress of cells, immunoglobulins, and cytokines into the lumen via the first and the second polymer layers, is observed.

In certain embodiments, the method may further include releasing from the first polymer layer and/or the second polymer layer molecules secreted by the population of cells.

In certain embodiments, the population of cells may survive for at least one month after the transplanting.

In certain embodiments, the population of cells comprises pancreatic islet cells and wherein the pancreatic islet cells sealed inside the device respond to glucose level of the subject by secreting insulin. In certain embodiments, the subject has or is predisposed to developing diabetes.

In certain embodiments, the first and second polymer layers are nanoporous polymer layers and may each include a supporting layer, such as, a microporous backing layer adhered to a surface of the nanoporous polymer layer.

In certain embodiments, the first and second polymer layers are microporous polymer layers.

In certain embodiments, the first polymer layer is a nanoporous polymer layer and the second polymer layer is a microporous polymer layer.

In certain embodiments, the first and second polymer layers are fabricated using the polymer poly-caprolactone (PCL).

In certain embodiments, the first and second polymer layers are sealed along the entire periphery of the device thereby providing a closed lumen.

In certain embodiments, the lumen comprises an opening at which the first and second polymer layers are not sealed to each other.

In certain embodiments, the lumen comprises an opening at which the first and second layers are not in contact with each other, the device further comprising a tubing comprising a first end and a second end distal to the first end, wherein the first end of the tubing is positioned in the opening and the second end is configured to introduce the population of cells into the lumen.

In certain embodiments, the lumen comprises a first opening and a second opening at which the first and second layers are not in contact with each other, the device further comprising a first tubing and a second tubing, each of the first and second tubing comprising a first end and a second end distal to the first end, wherein the first end of the first tubing is positioned in the first opening and the first end of the second tubing is positioned in the second opening, and wherein the second end of each tubing is used for ingress or egress of fluids from the lumen.

In certain embodiments, the method comprises after the transplanting, attaching the second ends of the first and second tubing to a fill port. In certain embodiments, the fill port comprises a first chamber in fluid communication at the fill port with the second end of the first tubing; and a second chamber in fluid communication at the fill port with the second end of the second tubing.

In certain embodiments, a thin film device for transplanting cells in a subject is provided. The device includes a first nanoporous or microporous polymer layer; a second nanoporous or microporous polymer layer, wherein the first and second polymer layers define a lumen between the first and second polymer layers; and a population of cells disposed in the lumen between the first and second polymer layers, wherein first and second layers are less than 15 μm thick, and the device has a surface area of 1 cm2to 5 cm2, and wherein (a) the pores in the first and second polymer layers limit ingress of cells, immunoglobulins, and cytokines into the lumen via the first and the second layers, and/or (b) the pores are sized to promote vascularization into the lumen of the device, and/or (c) the device is configured to limit foreign body response to the transplanted device, and (d) the pores are sized to release molecules secreted by the population of cells. In certain embodiments, first and second polymer layers are nanoporous layers and may each include a supporting layer, such as, a microporous backing layer adhered to a surface of the nanoporous polymer layer.

In certain embodiments, a method for making a device disclosed herein is provided. The method may include placing a first nanoporous or microporous polymer layer over a second nanoporous or microporous polymer layer, wherein the first and second polymer layers are similarly dimensioned; sealing the first and the second polymer layers along the periphery of the polymer layers leaving an unsealed area at a location along the periphery to provide an opening for access to a lumen defined between the first and second layers and the periphery of the polymer layers at which the polymer layers are sealed together, placing a population of cells into the lumen through the opening; and sealing the opening. In certain embodiments, the first and second polymer layers are sealed together via application of heat. In certain embodiments, the first and second polymer layers are sealed together via application of an adhesive.

These and other objects, advantages, and features of the invention will become apparent to those persons skilled in the art upon reading the details of the devices and methods as more fully described below.

