Gene Expression, Bacteria Viability and Survivability Following Spray Drying of Mycobacterium smegmatis

We find that Mycobacterium smegmatis survives spray drying and retains cell viability in accelerated temperature stress (40 °C) conditions with a success rate that increases with increasing thermal, osmotic, and nutrient-restriction stresses applied to the mycobacterium prior to spray drying. M.smegmatis that are spray dried during log growth phase, where they suffer little or no nutrient-reduction stress, survive for less than 7 days in the dry powder state at accelerated temperature stress conditions, whereas M. smegmatis that are spray dried during stationary phase, where cells do suffer nutrient reduction, survive for up to 14 days. M. smegmatis that are spray dried from stationary phase, subjected to accelerated temperature stress conditions, regrown to stationary phase, spray dried again, and resubmitted to this same process four consecutive times, display, on the fourth spray drying iteration, an approximate ten-fold increase in stability during accelerated temperature stress testing, surviving up to 105 days. Microarray tests revealed significant differences in genetic expression of M. smegmatis between log phase and stationary phase conditions, between naïve (non spray-dried) and multiply cycled dried M. smegmatis (in log and stationary phase), and between M. smegmatis in the dry powder state following a single spray drying operation and after four consecutive spray drying operations. These differences, and other phenotypical differences, point to the carotenoid biosynthetic pathway as a probable pathway contributing to bacteria survival in the spray-dried state and suggests strategies for spray drying that may lead to significantly greater room-temperature stability of mycobacteria, including mycobacterium bovis bacille Calmette-Guerin (BCG), the current TB vaccine

Injectable cryogel-based whole-cell cancer vaccines

A biomaterial-based vaccination system that uses minimal extracorporeal manipulation could provide in situ enhancement of dendritic cell (DC) numbers, a physical space where DCs interface with transplanted tumour cells, and an immunogenic context. Here we encapsulate GM-CSF, serving as a DC enhancement factor, and CpG ODN, serving as a DC activating factor, into sponge-like macroporous cryogels. These cryogels are injected subcutaneously into mice to localize transplanted tumour cells and deliver immunomodulatory factors in a controlled spatio-temporal manner. These vaccines elicit local infiltrates composed of conventional and plasmacytoid DCs, with the subsequent induction of potent, durable and specific anti-tumour T-cell responses in a melanoma model. These cryogels can be delivered in a minimally invasive manner, bypass the need for genetic modification of transplanted cancer cells and provide sustained release of immunomodulators. Altogether, these findings indicate the potential for cryogels to serve as a platform for cancer cell vaccinations

Shear-activated nanotherapeutics for drug targeting to obstructed blood vessels

Bio-Inspired Drug Delivery Noting that platelets naturally migrate to narrowed blood vessels characterized by high fluid shear stress, Korin et al. (p. 738 , published online 5 July; see the Perspective by Lavik and Ustin ) developed a nanoparticle-based therapeutic that uses a similar targeting mechanism to deliver a drug to vessels obstructed by blood clots. Aggregates of nanoparticles coated with the clot-dissolving drug tPA (tissue plasminogen activator) were designed to fall apart and release the drug only when encountering high fluid shear stress. In preclinical models, the bio-inspired therapeutic dissolved clots and restored normal blood flow at lower doses than free tPA, suggesting that this localized delivery system may help reduce the risk of side effects such as excessive bleeding. </jats:p