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The emergence of cell-based therapeutics, specifically the use of mesenchymal stromal/stem cells (MSCs), stands to significantly affect the future of targeted drug delivery technologies. MSCs represent a unique cell type, offering more than only regenerative potential but also site-specific inflammatory targeting and tissue infiltration. In this study, a versatile multicomponent delivery platform, combining MSC tropism with multistage nanovector (MSV)-mediated payload delivery, is debuted. It is demonstrated that the incorporation of drug-loaded MSVs bestows MSCs with the ability to transport anti-inflammatory payloads, achieving a fivefold increase in payload release without negatively impacting cellular functions, viability, extravasation, and inflammatory homing. When incorporated within MSCs, MSVs avoid rapid sequestration by filtering organs and conserve a 15-fold increase in local inflammatory targeting compared to healthy ears. Furthermore, this MSC-mediated MSV platform (M&Ms) rapidly triggers a 4.5-fold reduction of local inflammation compared to free drug and extends survival to 100% of treated mice in a lethal model of systemic inflammation.

The engineering of future generations of nanodelivery systems aims at the creation of multifunctional vectors endowed with improved circulation, enhanced targeting and responsiveness to the biological environment. Moving past purely bio-inert systems, researchers have begun to create nanoparticles capable of proactively interacting with the biology of the body. Nature offers a wide-range of sources of inspiration for the synthesis of more effective drug delivery platforms. Because the nano-bio-interface is the key driver of nanoparticle behavior and function, the modification of nanoparticles’ surfaces allows the transfer of biological properties to synthetic carriers by imparting them with a biological identity. Modulation of these surface characteristics governs nanoparticle interactions with the biological barriers they encounter. Building off these observations, we provide here an overview of virus- and cell-derived biomimetic delivery systems that combine the intrinsic hallmarks of biological membranes with the delivery capabilities of synthetic carriers. We describe the features and properties of biomimetic delivery systems, recapitulating the distinctive traits and functions of viruses, exosomes, platelets, red and white blood cells. By mimicking these biological entities, we will learn how to more efficiently interact with the human body and refine our ability to negotiate with the biological barriers that impair the therapeutic efficacy of nanoparticles.

Cancer treatment still represents a formidable challenge, despite substantial advancements in available therapies being made over the past decade. One major issue is poor therapeutic efficacy due to lack of specificity and low bioavailability. The progress of nanotechnology and the development of a variety of nanoplatforms have had a significant impact in improving the therapeutic outcome of chemotherapeutics. Nanoparticles can overcome various biological barriers and localize at tumor site, while simultaneously protecting a therapeutic cargo and increasing its circulation time. Despite this, due to their synthetic origin, nanoparticles are often detected by the immune system and preferentially sequestered by filtering organs. Exosomes have recently been investigated as suitable substitutes for the shortcomings of nanoparticles due to their biological compatibility and particularly small size (i.e., 30-150 nm). In addition, exosomes have been found to play important roles in cell communication, acting as natural carriers of biological cargoes throughout the body. This review aims to highlight the use of exosomes as drug delivery vehicles for cancer and showcases the various attempts used to exploit exosomes with a focus on the delivery of chemotherapeutics and nucleic acids.

Cancer treatment still remains a challenge due to the several limitations of currently used chemotherapeutics, such as their poor pharmacokinetics, unfavorable chemical properties, as well as inability to discriminate between healthy and diseased tissue. Nanotechnology offered potent tools to overcome these limitations. Drug encapsulation within a delivery system permitted i) to protect the payload from enzymatic degrada-tion/inactivation in the blood stream, ii) to improve the physicochemical properties of poorly water-soluble drugs, like paclitaxel, and iii) to selectively deliver chemotherapeutics to the cancer lesions, thus reducing the off-target toxicity, and promoting the intracellular internalization. To accomplish this purpose, several strategies have been developed, based on biological and physical changes happening locally and systemically as a consequence of tumorigenesis. Here, we will discuss the role of inflammation in the different steps of tumor development and the strategies based on the use of nanoparticles that exploit the inflammatory pathways in order to selectively target the tumor-associated microenvironment for therapeutic and diagnostic purposes

The advancement of nanotechnology toward more sophisticated bioinspired approaches has highlighted the gap between the advantages of biomimetic and biohybrid platforms and the availability of manufacturing processes to scale up their production. Though the advantages of transferring biological features from cells to synthetic nanoparticles for drug delivery purposes have recently been reported, a standardizable, batch-to-batch consistent, scalable, and high-throughput assembly method is required to further develop these platforms. Microfluidics has offered a robust tool for the controlled synthesis of nanoparticles in a versatile and reproducible approach. In this study, the incorporation of membrane proteins within the bilayer of biomimetic nanovesicles (leukosomes) using a microfluidic-based platform is demonstrated. The physical, pharmaceutical, and biological properties of microfluidic-formulated leukosomes (called NA-Leuko) are characterized. NA-Leuko show extended shelf life and retention of the biological functions of donor cells (i.e., macrophage avoidance and targeting of inflamed vasculature). The NA approach represents a universal, versatile, robust, and scalable tool, which is extensively used for the assembly of lipid nanoparticles and adapted here for the manufacturing of biomimetic nanovesicles.

A major challenge in regenerative medicine is to improve therapeutic cells’ delivery and targeting using an efficient and simple protocol. Mesenchymal stem cells (MSC) are currently employed for the treatment of inflammatory-based diseases, due to their powerful immunosoppressive potential. Here we report a simple and versatile method to transiently overexpress the hyaluronic acid (HA) receptor, CD44, on MSC membranes, to improve their homing potential towards an inflammatory site without affecting their behavior. The effect of HA-coatings on murine MSC was functionally determined both, in vitro and in vivo as a consequence of the transient CD44 overexpression induced by HA. Data obtained from the in vitro migration assay demonstrated a two-fold increase in the migratory potential of HA-treated MSC compared to untreated cells. In an LPS-induced inflamed ear murine model, HA-treated MSC demonstrated a significantly higher inflammatory targeting as observed at 72 hrs as compared to untreated cells. This increased accumulation for HA-treated MSC yielded a substantial reduction in inflammation as demonstrated by the decrease in the expression of pro-inflammatory markers and by the induction of a pro-regenerative environment.

The ability of nanoparticles to evade the immune system, cross biological barriers, and localize at the target tissue ultimately determines their therapeutic potential. Leukocytes naturally encompass all of these features and, therefore, provide great inspiration in biomimetic vectors. Herein, we present a hybrid drug delivery system, termed leukolike vectors, composed of a synthetic nanoporous silicon core cloaked with cellular membranes derived from circulating white blood cells. These particles possess the ability to avoid clearance by the mononuclear phagocyte system, interact with endothelial cells through receptor-ligand interaction, and effi ciently deliver a therapeutic payload to infl amed endothelia. Furthermore, in vivo studies revealed an ability to retain the leukocyte membrane's biological function following systemic administration, demonstrating prolonged circulation and improved tumor targeting abilities.

Recent advances in the field of nanomedicine have demonstrated that biomimicry can further improve targeting properties of current nanotechnologies while simultaneously enable carriers with a biological identity to better interact with the biological environment. Immune cells for example employ membrane proteins to target inflamed vasculature, locally increase vascular permeability, and extravasate across inflamed endothelium. Inspired by the physiology of immune cells, we recently developed a procedure to transfer leukocyte membranes onto nanoporous silicon particles (NPS), yielding Leukolike Vectors (LLV). LLV are composed of a surface coating containing multiple receptors that are critical in the cross-talk with the endothelium, mediating cellular accumulation in the tumor microenvironment while decreasing vascular barrier function. We previously demonstrated that lymphocyte function-associated antigen (LFA-1) transferred onto LLV was able to trigger the clustering of intercellular adhesion molecule 1 (ICAM-1) on endothelial cells. Herein, we provide a more comprehensive analysis of the working mechanism of LLV in vitro in activating this pathway and in vivo in enhancing vascular permeability. Our results suggest the biological activity of the leukocyte membrane can be retained upon transplant onto NPS and is critical in providing the particles with complex biological functions towards tumor vasculature.

A multitude of micro- and nanoparticles have been developed to improve the delivery of systemically administered pharmaceuticals, which are subject to a number of biological barriers that limit their optimal biodistribution. Bioinspired drug-delivery carriers formulated by bottom-up or top-down strategies have emerged as an alternative approach to evade the mononuclear phagocytic system and facilitate transport across the endothelial vessel wall. Here, we describe a method that leverages the advantages of bottom-up and top-down strategies to incorporate proteins derived from the leukocyte plasma membrane into lipid nanoparticles. The resulting proteolipid vesicles - which we refer to as leukosomes - retained the versatility and physicochemical properties typical of liposomal formulations, preferentially targeted inflamed vasculature, enabled the selective and effective delivery of dexamethasone to inflamed tissues, and reduced phlogosis in a localized model of inflammation.

Recently, engineering the surface of nanotherapeutics with biologics to provide them with superior biocompatibility and targeting towards pathological tissues has gained significant popularity. Although the functionalization of drug delivery vectors with cellular materials has been shown to provide synthetic particles with unique biological properties, these approaches may have undesirable immunological repercussions upon systemic administration. Herein, we comparatively analyzed unmodified multistage nanovectors and particles functionalized with murine and human leukocyte cellular membrane, dubbed Leukolike Vectors (LLV), and the immunological effects that may arise in vitro and in vivo. Previously, LLV demonstrated an avoidance of opsonization and phagocytosis, in addition to superior targeting of inflammation and prolonged circulation. In this work, we performed a comprehensive evaluation of the importance of the source of cellular membrane in increasing their systemic tolerance and minimizing an inflammatory response. Time-lapse microscopy revealed LLV developed using a cellular coating derived from a murine (i.e., syngeneic) source resulted in an active avoidance of uptake by macrophage cells. Additionally, LLV composed of a murine membrane were found to have decreased uptake in the liver with no significant effect on hepatic function. As biomimicry continues to develop, this work demonstrates the necessity to consider the source of biological material in the development of future drug delivery carriers.

This report describes a novel, one-pot synthesis of hybrid nanoparticles formed by a nanostructured inorganic silica core and an organic pH-responsive hydrogel shell. This easy-to-perform, oil-in-water emulsion process synthesizes fluorescently-doped silica nanoparticles wrapped within a tunable coating of cationic poly(2-diethylaminoethyl methacrylate) hydrogel in one step. Transmission electron microscopy and dynamic light scattering analysis demonstrated that the hydrogel-coated nanoparticles are uniformly dispersed in the aqueous phase. The formation of covalent chemical bonds between the silica and the polymer increases the stability of the organic phase around the inorganic core as demonstrated by thermogravimetric analysis. The cationic nature of the hydrogel is responsible for the pH buffering properties of the nanostructured system and was evaluated by titration experiments. Zeta-potential analysis demonstrated that the charge of the system was reversed when transitioned from acidic to basic pH and vice versa. Consequently, small interfering RNA (siRNA) can be loaded and released in an acidic pH environment thereby enabling the hybrid particles and their payload to avoid endosomal sequestration and enzymatic degradation. These nanoparticles, loaded with specific siRNA molecules directed towards the transcript of the membrane receptor CXCR4, significantly decreased the expression of this protein in a human breast cancer cell line (i.e., MDA-MB-231). Moreover, intravenous administration of siRNA-loaded nanoparticles demonstrated a preferential accumulation at the tumor site that resulted in a reduction of CXCR4 expression.

Current delivery platforms are typically designed for prolonged circulation that favors superior accumulation of the payload in the targeted tissue. The design of efficient surface modifications determines both a longer circulation time and targeting abilities of particles. The optimization of synthesis protocols to efficiently combine targeting molecules and elements that allow for an increased circulation time can be challenging and almost impossible when several functional elements are needed. On the other side in the last decade, the development of bioinspired technologies was proposed as a new approach to increase particle safety, biocompatibility and targeting, while maintaining the synthesis protocols simple and reproducible. Recently we developed a new drug delivery system inspired by the biology of immune cells called Leukolike vector (LLV) and formed by a nanoporous silicon core and a shell derived from leucocyte cell membrane. The goal of this study is to investigate the protein content of the LLV, thus here we show the proteomic profiling of LLV demonstrating that our approach can be used to modify the surface of synthetic particle with more than 150 leukocyte membrane associated proteins that determine particle safety, circulation time and targeting abilities towards inflamed endothelium., Current delivery platforms are typically designed for prolonged circulation that favors superior accumulation of the payload in the targeted tissue. The design of efficient surface modifications determines both a longer circulation time and targeting abilities of particles. The optimization of synthesis protocols to efficiently combine targeting molecules and elements that allow for an increased circulation time can be challenging and almost impossible when several functional elements are needed. On the other hand, in the last decade, the development of bioinspired technologies was proposed as a new approach with which to increase particle safety, biocompatibility and targeting, while maintaining the synthesis protocols simple and reproducible. Recently, we developed a new drug delivery system inspired by the biology of immune cells called leukolike vector (LLV) and formed by a nanoporous silicon core and a shell derived from the leucocyte cell membrane. The goal of this study is to investigate the protein content of the LLV. Here we report the proteomic profiling of the LLV and demonstrate that our approach can be used to modify the surface of synthetic particles with more than 150 leukocyte membraneassociated proteins that determine particle safety, circulation time and targeting abilities towards inflamed endothelium.