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Featured Application: A synthetic gene that codes for a protein comprised of a streptavidin domain for binding biotin-labeled cargo, a urokinase cleavage domain for release by urokinase plasminogen activator, and a PLAP domain for cell-surface expression enables effective cell-based delivery of small molecules and nanostructures to tumors. Many cytotherapy applications focus on delivering a therapeutic molecule or nanoparticle to a disease site. One challenging step in this delivery is releasing the therapeutic molecule from the delivery cell upon arrival at the delivery sight. Here a protein is designed and expressed that can bind a biotin-labeled cargo and release that cargo in response to the presence of urokinase plasminogen activator. A gene was designed that coded for a protein that contained a streptavidin domain for binding biotin-labeled cargo, a urokinase cleavage domain for release by urokinase plasminogen activator, and a PLAP domain for cell-surface expression. The utility of the resultant protein was tested with biotin (5-fluorescein) and a biotinylated PLGA nanoparticle to test the performance of the delivery systems with models for small molecule drugs and nanoformulations. When expressed in neural progenitor cells (C17.2), the designed protein was able to bind both the biotin (5-fluorescein) and the biotinylated PLGA nanoparticles and was able to release the biotin (5-fluorescein) in response to urokinase plasminogen activator. This designed, multi-domain protein may prove useful as a method for specifically releasing a cargo from delivery cells at a target site. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) are phospholipid and protein constructs which are continuously secreted by cells in the form of smaller (30–200 nm) and larger (micron size) particles. While all of these vesicles are called as EVs, the smaller size are normally called as exosomes. Small EVs (sEVs) have now been explored as a potential candidate in therapeutics delivery owing to their endogenous functionality, intrinsic targeting property, and ability to cooperate with a host defense mechanism. Considering these potentials, we hypothesize that immune cell-derived sEVs can mimic immune cell to target cancer. However, different sEVs isolation technique reported poor yield and loss of functional properties. To solve this problem, herein we hybridized sEVs with synthetic liposome to engineer vesicles with size less than 200 nm to mimic the size of exosome and named as hybrid exosome (HE). To achieve this goal, sEVs from mouse macrophage was hybridized with synthetic liposome to engineer HE. The fluorescence-based experiment confirmed the successful hybridization process yielding HE with the size of 177 ± 21 nm. Major protein analysis from Blot techniques reveal the presence of EV marker proteins CD81, CD63, and CD9. Differential cellular interaction of HE was observed when treated with normal and cancerous cells thereby supporting our hypothesis. Moreover, a water-soluble doxorubicin was loaded in HE. Drug-loaded HE showed enhanced toxicity against cancer cells and pH-sensitive drug release in acidic condition, benefiting drug delivery to acidic cancer environment. These results suggest that the engineered HE would be an exciting platform for tumor-targeted drug delivery. Extracellular vesicles (EVs) are phospholipid and protein constructs which are continuously secreted by cells in the human body. These vesicles can efficiently deliver their parental biomolecules to the recipient cells and assist in intracellular communication without a direct cell-to-cell contact. Moreover, they have the ability to perform some of the molecular task similar to that of its parent cells. For example, exosome derived from immune cells can seek for diseased and/or inflammatory cells by reading the cell surface proteins. However, different EVs isolation techniques reported poor yield and loss of functional properties. Therefore, to overcome this limitation, we herein propose to re-engineer immuno-exosome with a synthetic liposome as a refined biomimetic nanostructure for the delivery of doxorubicin (clinical drug) for breast cancer treatment. [ABSTRACT FROM AUTHOR]

Therapeutic efficacy of a systemic drug delivery largely depends on the targeting design of the delivery system, which tackles with circulatory traffic and prevents the nonspecific distribution of the drug in the wide range of vital organs. A drawing attention has been given to a biomimetic cloaking of the synthetic drug delivery nanoparticle using mammalian cell-ghosts, which has shown the installment of the biological complexity of the original cells thereby acting as naïve cells, to precisely delivery drug to the intended target. Align towards this direction; we developed a membrane camouflage fusogenic liposomal delivery system “NKsome” for targeted tumor therapy using Natural Killer (NK) cell-ghost, which naturally undergoes immunosurveillance of diseased/stress cells. The engineered NKsome shows successful retention of NK cell membrane-associated targeting protein on its surface. With its excellent biocompatibility, NKsome shows a higher affinity towards cancer than normal cells as demonstrated by in vitro flow-passage assay, and exhibits enhanced tumor homing efficiency in-vivo with an extended plasma residence time of 18 h. Moreover, the therapeutic potential of doxorubicin-loaded NKsome shows promising antitumor activity in vivo against MCF-7 induced tumor model. Overall results illustrate the therapeutic advantages of NK cell biomimicry capable of communicating like immune cells for cooperative drug delivery. [ABSTRACT FROM AUTHOR]

In the present study, a biomimetic nanoconstruct (BNc) with a multimodal imaging system is engineered using tumor homing natural killer cell membrane (NKM), near‐infrared (NIR) fluorescent dye, and gadolinium (Gd) conjugate‐based magnetic resonance imaging contrast agent onto the surface of a polymeric nanoparticle. The engineered BNc is 110 ± 20 nm in size and showed successful retention of NKM proteins. The magnetic properties of the BNc are found to be tunable from 2.1 ± 0.17 to 5.3 ± 0.5 mm−1 s−1 under 14.1 T, by adjusting the concentration of Gd‐lipid conjugate onto the surface of the BNc. Confocal imaging and cell sorting analysis reveal a distinguishable cellular interaction of the BNc with MCF‐7 cells in comparison to that of bare polymeric nanoparticles suggesting the tumor homing properties of NKM camouflage system. The in vitro cellular interaction results are further confirmed by in vivo NIR fluorescent tumor imaging and ex vivo MR imaging, respectively. Pharmacokinetics and biodistribution analysis of the BNc show longer circulation half‐life (≈9.5 h) and higher tumor accumulation (10% of injected dose) in MCF‐7 induced tumor‐bearing immunodeficient NU/NU nude mice. Owing to the proven immunosurveillance potential of NK‐cell in the field of immunotherapy, the BNc engineered herein would hold promises in the design consideration of nanomedicine engineering. A biomimetic nanoconstruct with a multimodal imaging system is engineered using tumor homing natural killer cell membrane, near‐infrared fluorescent dye, and a gadolinium conjugate‐based magnetic resonance imaging contrast agent onto the surface of a polymeric nanoparticle. The engineered nanoconstruct shows an extended plasma half‐life and a differential targeting specificity toward cancer. [ABSTRACT FROM AUTHOR]