Two-dimensional (2-D) surface layer (S-layer) protein lattices isolated from the gram-positive bacterium Deinococcus radiodurans and the acidothermophilic archaeon Sulfolobus acidocaldarius were investigated and compared for their ability to biotemplate the formation of self-assembled, ordered arrays of inorganic nanoparticles (NPs). The NPs employed for these studies included citrate-capped gold NPs and various species of CdSe/ZnS core/shell quantum dots (QDs). The QD nanocrystals were functionalized with different types of thiol ligands (negative- or positive-charged/short- or long-chain length) in order to render them hydrophilic and thus water-soluble. Transmission electron microscopy, Fourier transform analyses, and pair correlation function calculations revealed that ordered nanostructured arrays with a range of spacings (approximately 7-22 nm) and different geometrical arrangements could be fabricated through the use of the two types of S-layers. These results demonstrate that it is possible to exploit the physicochemical/structural diversity of prokaryotic S-layer scaffolds to vary the morphological patterning of nanoscale metallic and semiconductor NP arrays.

Genetically-modified T cells expressing chimeric antigen receptors (CAR) exert anti-tumor effect by identifying tumor-associated antigen (TAA), independent of major histocompatibility complex. For maximal efficacy and safety of adoptively transferred cells, imaging their biodistribution is critical. This will determine if cells home to the tumor and assist in moderating cell dose. Here, T cells are modified to express CAR. An efficient, non-toxic process with potential for cGMP compliance is developed for loading high cell number with multi-modal (PET-MRI) contrast agents (Super Paramagnetic Iron Oxide Nanoparticles – Copper-64; SPION-64Cu). This can now be potentially used for 64Cu-based whole-body PET to detect T cell accumulation region with high-sensitivity, followed by SPION-based MRI of these regions for high-resolution anatomically correlated images of T cells. CD19-specific-CAR+SPIONpos T cells effectively target in vitro CD19+ lymphoma.

Adoptive transfer of primary T cells genetically modified to have desired specificity can exert an anti-tumor response in some patients. To improve our understanding of their therapeutic potential we have developed a clinically-appealing approach to reveal their in vivo biodistribution using nanoparticles that serve as a radiotracer for imaging by positron emission tomography (PET). T cells electroporated with DNA plasmids from the Sleeping Beauty transposon/transposase system to co-express chimeric antigen receptor (CAR) specific for CD19 and Firefly luciferase (ffLuc) were propagated on CD19+ K562-derived artificial antigen presenting cells. The approach to generating our clinical-grade CAR+ T cells was adapted to electro-transfer of gold nanoparticles (GNP) functionalized with 64Cu2+ using the macrocyclic chelator (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, DOTA) and polyethyleneglycol (GNP-64Cu/PEG2000). MicroPET/CT was used to visualize CAR+EGFPffLucHyTK+GNP-64Cu/PEG2000+ T cells and correlated with bioluminescence imaging and assessment of radioactivity. These data demonstrate that GNPs conjugated with 64Cu2+ can be prepared as radiotracer for PET and used to image T cells using an approach that has translational implications.

An artificial cell-signaling pathway is developed that capitalizes on the T-cell’s innate extravasation ability and transforms it into a vector (T-cell Biofactory) for synthesizing calibrated amounts of engineered proteins in vivo. The modularity of this pathway enables reprogramming of the T-cell Biofactory to target biomarkers on different disease cells, e.g. cancer, viral infections, autoimmune disorders. It can be expected that the T-cell Biofactory leads to a “living drug” that extravasates to the disease sites, assesses the disease burden, synthesizes the calibrated amount of engineered therapeutic proteins upon stimulation by the diseased cells, and reduces targeting of normal cells.