Bioinspired oral delivery devices

The fate of the transferrin receptor during in vitro maturation of sheep reticulocytes has been followed using FITC- and 125I-labeled anti-transferrin-receptor antibodies. Vesicles containing peptides that comigrate with the transferrin receptor on polyacrylamide gels are released during incubation of sheep reticulocytes, tagged with anti-transferrin-receptor antibodies. Vesicle formation does not require the presence of the anti-transferrin-receptor antibodies. Using 125I-surface-labeled reticulocytes, it can be shown that the 125I-labeled material which is released is retained by an immunoaffinity column of the anti-transferrin-receptor antibody. Using reticulocytes tagged with 125I-labeled anti-transferrin-receptor antibodies to follow the formation of vesicles, it can be shown that at 0 degree C or in phosphate-buffered saline the rate of vesicle release is less than that at 37 degrees C in culture medium. There is selective externalization of the antibody-receptor complex since few other membrane proteins are found in the externalized vesicles. The anti-transferrin-receptor antibodies cause redistribution of the receptor into patches that do not appear to be required for vesicle formation. Show more

Genome editing, involving precise manipulation of cellular DNA sequences to alter cell fates and organism traits, offers the potential to both understand human genetics and cure genetic disease as never before. Scientific, technical and ethical aspects of employing CRISPR technology for therapeutic applications in humans are discussed, focusing on specific examples that highlight both opportunities and challenges. Genome editing is or will soon be in the clinic for several diseases, with more applications in the pipeline. The rapid pace of the field demands active efforts to ensure responsible use of this breakthrough technology to treat, cure and prevent genetic disease. Show more

The pervasive view of bacteria as strictly pathogenic has given way to an appreciation of the widespread prevalence of beneficial microbes within the human body 1–3 . Given this milieu, it is perhaps inevitable that some bacteria would evolve to preferentially grow in environments that harbor disease and thus provide a natural platform for the development of engineered therapies 4–6 . Such therapies could benefit from bacteria that are programmed to limit bacterial growth while continually producing and releasing cytotoxic agents in situ 7–10 . Here, we engineer a clinically relevant bacterium to lyse synchronously at a threshold population density and to release genetically encoded cargo. Following quorum lysis, a small number of surviving bacteria reseed the growing population, thus leading to pulsatile delivery cycles. We use microfluidic devices to characterize the engineered lysis strain and we demonstrate its potential as a drug delivery platform via co-culture with human cancer cells in vitro. As a proof of principle, we track the bacterial population dynamics in ectopic syngeneic colorectal tumors in mice. The lysis strain exhibits pulsatile population dynamics in vivo, with mean bacterial luminescence that remained two orders of magnitude lower than an unmodified strain. Finally, guided by previous findings that certain bacteria can enhance the efficacy of standard therapies 11 , we orally administer the lysis strain, alone or in combination with a clinical chemotherapeutic, to a syngeneic transplantation model of hepatic colorectal metastases. We find that the combination of both circuit-engineered bacteria and chemotherapy leads to a notable reduction of tumor activity along with a marked survival benefit over either therapy alone. Our approach establishes a methodology for leveraging the tools of synthetic biology to exploit the natural propensity for certain bacteria to colonize disease sites. Show more