Making a Case: Nanofabrication Techniques in Encapsulated Cell Therapy for People with Diabetes

Abstract

A nanoporous immunoisolative case/capsule that encases/encapsulates insulin-secreting cells vastly expands the source of therapeutic cells available for grafting in people with diabetes, including cells from animal sources, stem cells, and genetically engineered cells. These encapsulated cellular grafts potentially provide an endogenous, renewable, and long-term source of insulin without the need for pharmacological immunosuppression.Micro-and nanofabrication techniques used principally in the semiconductor industry can play a positive role in encapsulated cell therapy. Many of these techniques do not have direct applicability in cell encapsulation, but can be leveraged to develop processes suitable for this application. This commentary highlights the salient features of an effective cell encapsulation system, enumerates limitations of existing encapsulation schemes, and touches upon progress in key areas of encapsulation technology; one example of how micro-and nanofabrication technology may be used to develop a more effective platform for cell encapsulation is presented. This commentary urges further exploration and expansion of techniques used traditionally in electronics and optics for cell-based therapy in people with diabetes.

Membranes to achieve immunoprotection of transplanted islets

“…With the development of nanofabrication technologies such as electron-beam lithography and nanoimprinting, nanoporous membranes have been fabricated in the commonly used photosensitive polymer SU-8 (epoxy-based) by Gimi et al (181-184). Biocompatibility of SU-8 has already been studied and found satisfactory(185).…”

“…The fabrication of nanoporous SU-8 membranes occurs in two steps. A silicon (Si) mold is first created by conventional electron beam lithography(183, 184). In order to reduce the dimensions of the mold features down to the final target of a 20 nm wide grating and 200 nm pitch, controlled and cyclic oxidation and etching steps are applied.…”