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A contrast agent (CA) in magnetic resonance imaging (MRI) is now an essential add-on to obtain high-quality contrast-enhanced anatomical images for disease diagnosis and monitoring the treatment response. However, the rapid elimination of CAs by the immune system and excretion by the renal route has limited its application. As a result, the CA dose for effective contrast is ever-increasing, resulting in toxic side effects such as gadolinium (Gd) related nephrogenic systemic fibrosis (NSF) toxicity. Considering the widespread application of Gd-based CAs, it is now very important to revisit their formulation in order to improve their local concentration and minimize their dose while achieving clinical goals. Therefore, we have adapted a unique strategy to maximize Gd delivery to the target site using macrophage cell-derived extracellular vesicles (EVs) reconstructed with a Gd-conjugated liposomal system herein called gadolinium infused hybrid EVs (Gd-HEVs). We hypothesize that Gd-HEVs, owing to the presence of immune cell-derived EV protein cargo, can effectively disguise themselves as a biological entity, prolong the retention time for contrast enhancement, and show tumor specificity. Incorporation of Gd into nanoformulations can enhance the longitudinal relaxivity r1 by reducing the tumbling rate of paramagnetic metal complexes. Here, Gd-HEVs showed a higher r1 relaxivity of 9.86 mM−1 s−1 compared to 3.98 mM−1 s−1 of Magnevist® at an equivalent Gd concentration, when measured by clinical 3T MRI. This will allow us to reduce the clinically used Gd concentration about three-fold while maintaining contrast in the clinical window thereby supporting our hypothesis. Furthermore, Gd-HEVs showed a preferential cellular interaction and accumulation towards cancer cells compared to non-cancer cells, both in vitro and in vivo. More importantly, Gd-HEVs showed excellent contrast enhancement in the blood vasculature with a higher retention time compared to its counterpart, Magnevist®. Our study successfully showed that the incorporation of Gd in the EV framework can help to enhance the contrast ability, and therefore it can be a platform technology for the development of safer MRI contrast agents.

Recent progress in bioimaging nanotechnology has a great impact on the diagnosis, treatment, and prevention of diseases by enabling early intervention. Among different types of bioimaging modalities, contrast-enhanced magnetic resonance imaging using paramagnetic gadolinium-based molecular contrast agents (GBCAs) are most commonly used in clinic. However, molecular GBCAs distribute rapidly between plasma and interstitial spaces with short half-lives limiting its clinical impacts. To improve the properties of GBCAs, herein an effort has been put forth by incorporating GBCA into nanoscale system mimicking the property of red blood cell (RBC) that could facilitate contrast enhancement and prolong intraluminal retention in the body. The proposed nanoconstruct is made up of polymeric-core labeled with lipid conjugated GBCA followed by the imprint of the RBC membrane concealment layer to enhance stability and biocompatibility. Meanwhile, the confinement strategy of GBCA was implemented to accelerate magnetic properties of nanoconstruct providing longitudinal-relaxivity (r1) to 12.78 ± 0.29 (mM s)-1. Such improvement in r1 was further confirmed by enhanced contrast in the vascular angiography of the murine model. Given higher colloidal stability and tunable magnetic properties, nanoconstruct proposed herein is a promising platform technology for the applications where enhanced plasma residence time and magnetic properties are necessary for diagnosis and therapy.

Biocompatible polymeric and lipid nanoparticles are under extensive investigation as anticancer nanomedicines due to the ease of chemical modification in both polymer and lipid in order to target the respective disease environment. However, microenvironment and molecular heterogeneity in tumors pose a great challenge to delivering anticancer drugs or imaging agents precisely to the target, further limiting their applications. As a result, existing nanomedicine formulations rely on a passive-drug targeting mechanism taking advantage of leaky tumor vasculature. However, one strategy is not fit for all due to the molecular dissimilarities between cancers. Therefore, more research on tumor-specific receptors is needed to maximize drug delivery, while minimizing drug-related adverse effects. In addition, a high degree of the immunocompatibility and aqueous stability of the delivery device is essential to maximize delivery efficiency. Herein, we are addressing the aforementioned requirements in cancer management by engineering a receptor-specific anticancer nanomedicine as a composite of polymer and lipids. We are presenting a tumor seeking cyclic LyP-1 peptide integrated core–shell polymer–lipid composite nanoparticle (NP) that targets the overexpressed p32 receptor in cancer cells. The designed nanoconstruct is composed of poly(lactide-co-glycolic acid) as a skeleton and a cargo reservoir, a phospholipid with polyethylene glycol as a stabilizer, and LyP-1 as a targeting motif. We studied cellular interaction and targeting ability by accessing the full spectrum of biodistribution using NPs labeled with near-infrared dye as an imaging tracer in vivo. The NPs are spherical and monodispersed with an average size of 68 ± 6 nm and negative zeta potential. These particles are highly stable in physiological conditions over the period with a lower polydispersity index (PDI = 0.15). Furthermore, the nanoparticles showed excellent biocompatibility in vitro, with significantly higher uptake by mouse osteosarcoma compared to non-cancerous fibroblasts. Likewise, LyP-1 NP showed nearly three-fold enhancement in tumor accumulation in vivo compared to its non-targeted counterparts in the K7M2 tumor. Considering the overexpression of p32 in many cancers, the proposed nanoconstruct could hold promises in the therapeutic planning of a wide range of tumors.

Red blood cells (RBCs) are the natural resident of the vascular lumen, therefore delivery of any agents within the vascular lumen could benefit by unique natural transporting features of RBCs. RBCs continuously circulate for ∼100 days before being sequestered in the spleen, they only extravasate at sites of vascular hemorrhage. Taking advantages of these features, we engineered RBC as a carrier in order to design a unique delivery system capable of delivering X-ray computed tomography (CT) contrast agents, gold nanoparticles (AuNPs), thereby acting as CT-contrast agent. A strategic membrane fusion technique was used to engineer the surface of RBC with gold nanoparticles in this in vitro study without altering its shape, size, and surface properties.

Superparamagnetic iron oxide nanoparticles (SPIONs) are highly biocompatible and have a versatile synthetic technique based on coprecipitation, reduction-precipitation, and hydrothermal methods, where Fe3+ and Fe2+ react in aqueous solutions; both these ions are present in our body and have clear metabolic pathways; therefore, they have attracted extensive research interest and development in the field of diagnostic imaging and therapy. However, most SPION-based clinical diagnostic contrast agents are discontinued due to severe pain, low transverse magnetic relaxivity range of 80–180 mM−1 s−1, shorter circulation half-life, and lack of disease specificity. Therefore, in this study, we engineered a bone cancer-targeted hybrid nanoconstruct (HNC) with a high transverse magnetic relaxivity of 625 mM−1 s−1, which was significantly higher than that of clinical contrast agents. The engineered HNC is peripherally decorated with a bone-seeking agent, alendronic acid-conjugated phospholipid, exhibiting a hydrodynamic size of 80 nm with a negative surface potential, −35 mV. The interior skeleton of the HNC is composed of biodegradable and biocompatible poly(L-lactic-co-glycolic acid) (PLGA), in which 5 nm SPIONs are confined. We have successfully tuned the distance between the confined SPIONs from 0.5 to 4 nm, as revealed by transmission electron microscopy (TEM) images and magnetic resonance image (MRI) phantoms. This cluster confinement dramatically enhances magnetic relaxivity possibly due to the increase in net local magnetization due to proximal field inhomogeneity. In an in vitro examination, 80% of HNC is found to bind with hydroxyapatite (HAp), which when characterized by TEM shows a painting of SPIONs over a HAp crystal. HNC is found to accumulate in mouse osteosarcoma tumor (K7M2 tumor model); both MRI and histological examination of the tumor show the potential of HNC as targeting agents for diagnosis of tumor in the bone.

In vitro cell-nanoparticle (NP) studies involve exposure of NPs onto the monolayer cells growing at the bottom of a culture plate, and assumed that the NPs evenly distributed for a dose-responsive effect. However, only a few proportion of the administered dose reaches the cells depending on their size, shape, surface, and density. Often the amount incubated (administered dose) is misled as a responsive dose. Herein, we proposed a cell adhesion-migration (CAM) strategy, where cells incubated with the NP coated cell culture substrate to maximize the cell-NP interaction and investigated the physiological properties of the cells. In the present study, cell adhesion and migration pattern of human breast cancer cell (MCF-7) and mouse melanoma cell (B16-F10) on cell culture substrate decorated with toxic (cetyltrimethylammonium bromide, CTAB) and biocompatible (poly (sodium 4-styrenesulphonate), PSS) gold nanoparticles (AuNPs) of different sizes (5 and 40nm) were investigated and evaluated for cellular uptake efficiency, proliferation, and toxicity. Results showed enhanced cell adhesion, migration, and nanoparticle uptake only on biocompatible PSS coated AuNP, irrespective of its size. Whereas, cytotoxic NP shows retard proliferation with reduced cellular uptake efficiency. Considering the importance of cell adhesion and migration on cellular uptake and cytotoxicity assessment of nanoparticle, CAM strategy would hold great promises in cell-NP interaction studies.

Understanding the RNA nano–bio interface is critical to advance RNA based therapeutics. A relevant RNA polyinosinic:cytidilic acid (poly I:C) is perhaps the best studied in clinical trials and is now considered an antimetastatic RNA targeting agent. Also, zinc oxide nanoparticle (ZnO NP) has well-known anticancer activity. In this work, we explore the RNA nano–bio interface of poly I:C, its mononucleotides and homopolymers with ZnO NP by UV, fluorescence and fourier transform infrared (FTIR) spectroscopies. The loading method and ionic concentration (1.0 M Na+) were optimized for greater physical association of RNA with the NP, providing greater payload (150 μg/mg NP). The physical parameters of RNA nano–bio interaction, denoting the degree of association, were quantified by modified Stern–Volmer equations (Kb = 329.6 g–1 L). This interface was further studied by two-dimensional fluorescence difference spectroscopy (2D-FDS), where greater interaction was indicated by considerable quenching of the fluoresc...

Near infrared (NIR) mediated photothermal therapy and magnetic resonance imaging (MRI) are promising treatment and imaging modalities in the field of cancer theranostics. Gold nanorods are the first choice of materials for NIR-mediated photothermal therapy due to their strong localized surface plasmon resonance (LSPR) at NIR region. Similarly, gadolinium based MRI contrast agents have an ability to increase the ionic and molecular relaxivity, thereby enhancing the solvent proton relaxation rate resulting in contrast enhancement. Herein, the effort has been made to engineer a dual front theranostic agent with combined photothermal and magnetic resonance imaging capacity using gadolinium tethered gold nanorods (Gd3+-AuNR). NIR-responsive gold nanorods were surface fabricated by means of Au-thiol interaction using a thiolated macrocyclic chelator that chelates Gd3+ ions, and further stabilized by thiolated polyethylene glycol (PEG-SH). The magnetic properties of the Gd3+-AuNR displayed an enhanced r 1 relaxivity of 12.1 mM–1s–1, with higher biological stability, and contrast enhancement in both solution state and in cell pellets. In-vitro (cell-free) and ex-vivo (on pig skin) analysis of the Gd3+-AuNR shows enhanced photothermal properties as equivalent to that of the raw AuNR. Furthermore, Gd3+-AuNR showed competent cellular entry and intracellular distribution as revealed by hyperspectral microscopy. In addition, Gd3+-AuNR also exhibits significant thermal ablation of B16–F10 cells in the presence of NIR. Thus, Gd3+-AuNR features a significant theranostic potential with combined photothermal and imaging modality, suggesting a great potential in anticancer therapy.

Endosomal degradation of the nanoparticle is one of the major biological barriers associated with the drug delivery system. Nanoparticles are internalized in the cell via different endocytosis pathways, where they are first delivered to early endosomes which mature to the late endosome and to the lysosome. During this journey, NP encounters a harsh chemical environment resulting in the degradation of NP and its content. This process is collectively called as intracellular defenses against foreign materials. Therefore, to avoid this degradative fate, the endosomal escape technique has been explored following membrane fusion or membrane destabilization mechanisms. However, these methods are limited to the application due to non-specific membrane fusion. To overcome this limitation, we have designed pH-responsive liposome made up of 3s-[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol hydrochloride (DC-liposome) in which the cationic nitrogen of the ammonium moiety occupies only ∼2.5 % of the molecule. Such a small percentage of the cationic moiety is sufficient enough to exhibit pH-responsive properties while maintaining the biocompatibility of the DC-liposome. DC-liposome showed pH-dependent cationic properties due to the protonation of DC-moiety at acidic pH. The fluorescence-based experiment confirmed pH-dependent fusogenic properties of DC-liposome. Furthermore, the endosomal colocalization study revealed higher localization of DC-liposome in the early endosome compared to that of the late endosome, suggesting possible endosomal escape. Elevated cationic and fusogenic properties of DC-liposome at acidic pH can mediate membrane fusion with anionic endosomal membrane via electrostatic interaction, thereby causing endosomal escape. Moreover, doxorubicin-loaded DC-liposome showed higher cytotoxicity than that of free doxorubicin further supporting our clam of endosomal escape. These findings suggest the potential of DC-liposome to break the endosomal barriers to enhance the therapeutic efficacy thereby guiding us in design consideration in the field of stimuli-responsive delivery agents.

Nanotechnology has gained significant penetration to different fields of medicine including drug delivery, disease interrogation, targeting and bio-imaging. In recent years, efforts have been put forth to assess the use of this technology in biodetoxification. In this review, we will discuss the current status of nanostructured biomaterials/nanoparticle (NP)-based technologies as a candidate biodetoxifying agent. Patient hospitalization due to illicit drug consumption, suicidal attempts and accidental toxin exposure are major challenges in the medical field. Overdoses of drugs/toxic chemicals or exposure to bacterial toxins or poisons are conventionally treated by voiding the stomach, administering activated charcoal or by using specific antidotes, if the toxin is known. Because of the limitations of these methods for safe and effective detoxification, advancements in nanotechnology may offer novel ways in intoxication support by using nanostructured biomaterials, such as liposomes, micellar nanocarriers, liquid crystalline nanoassemblies and ligand-based NPs.

Biodegradable Nanoparticles (NPs) are under intense investigation due to their potential application in targeted drug delivery. Upon their entry to the biological system, they encounter the immune system, which limits their availability at the intended site. Most importantly, the innate immune system is the one that acts as the first line of defense against foreign materials. It can be activated by collectin proteins which recognize the structural pattern of polysaccharide on the surface of microorganisms. NPs may interact with these proteins in a similar way, and the interaction may lead to beneficial outcomes in vaccine delivery. On the other hand, in targeted drug delivery, it is desirable for the NPs not to be recognized as foreign material as this may lead to their fast elimination from the system through mechanism such as opsonization. We investigated the interaction of PEGylated and un-PEGylated PLGA NPs with Recombinant Human Mannose-Binding Protein (HMBP) in an effort to understand the effect of surface modification on their binding to the protein. Results show that both PLGA-COOH and PLGA-PEG-NH2 bind to HMBP as studied using dynamic light scattering (DLS), fluoresce and UV-vis spectroscopy. However, their binding is shown to have different effect on the structure of the protein. Study done using fluorescence spectroscopy displayed a decrease in fluorescence emission of the protein upon binding to PLGA-COOH. On the other hand the fluorescence emission of the protein increased upon binding to the PLGA-PEG-NH2 indicating conformational changes in the protein structure.

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. Statement of Significance 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.

Gold nanorods (AuNRs) possess unique photothermal properties due to their strong plasmonic absorption in the near-infrared region of the electromagnetic spectrum. They have been explored widely as an alternative or a complement to chemotherapy in cancer treatment. However, the use of AuNRs as an injectable medicine is greatly hindered by their stability in biological media. Therefore, studies have been focused on improving the stability of AuNRs by introducing biocompatible surface functionalizations such as polyethylene glycol (PEG) coatings. However, these coatings can affect heat conduction and alter their photothermal behavior. Herein, we studied how functionalization of AuNRs with PEG chains of different molecular weights determined the temperature distribution of suspensions under near-infrared irradiation, cell uptake in vitro, and hyperthermia-induced cytotoxicity. Thermogravimetric analysis of the PEG-conjugated AuNRs exhibited slightly different PEG mass fractions of 12.0%, 12.7%, and 18.5% for PEG chains with molecular weights of 2, 5, and 10 kDa, respectively, implying distinct structures for PEG brushes. When exposed to near-infrared radiation, we found greater temperatures and temperature gradients for longer PEG chains, while rapid aggregation was observed in unmodified (raw) AuNRs. The effect of the PEG coating on heat transport was investigated using molecular dynamics simulations, which revealed the atomic scale structure of the PEG brushes and demonstrated lower thermal conductivity for PEG-coated AuNRs than for unmodified AuNRs. We also characterized the uptake of the AuNRs into mouse melanoma cells in vitro and determined their ability to kill these cells when subjected to near-infrared radiation. For all PEG-coated AuNRs, exposure to 10 s of near-infrared radiation significantly reduced cell viability relative to unirradiated controls, with this viability further decreasing with increasing AuNR doses, indicating potential phototherapeutic effects. The 5 kDa PEG coating appeared to yield the best performance, yielding significant phototoxicity at even the lowest dose considered (0.5 μg mL-1), while also exhibiting high colloidal stability, which could help in rational design consideration of AuNRs for NIR induced photothermal therapy.

Multifunctional theranostic gadolinium infused liposomes containing the chemotherapeutic drug, doxorubicin (DOX), in its core are designed as potential candidates for diagnosis and therapy of various cancers. In these theranostic liposomes, Gd3+ ions are chelated by the macrocyclic chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, which is covalently linked to the hydrophilic head moiety of the phospholipid. Therefore, the Gd3+ labels are an integral part of the lipid bilayer of liposomal construct. The physical properties of the Gd-infused liposomes were characterized including drug loading, drug release kinetics, cellular consequences, and T1 weighted magnetic properties. The theranostic liposomes exhibits uniform size distribution (hydrodynamic size of 150 ± 10 nm) and a high drug loading efficiency with sustained drug release characteristic. Due to stable Gd3+ in their lipid bilayers, the theranostic liposomes displayed an enhanced r1 relaxivity of 12.3 mM−1 s−1 at 14.1 T, which is three times higher than that of currently used Gd-based contrast agent (Magnivest®: 4.1 mM−1 s−1, 1.4 T). Moreover, cellular uptake studies revealed that these theranostic liposomes exhibit higher structural integrities inside B16-F10 melanoma cells. It shows uniform intracellular distribution throughout the cells. In vitro cytotoxicity revealed that Gd-infused liposomes have excellent biocompatibility without significant cytotoxicity, whereas they showed higher cellular toxicity when loaded with DOX against B16-F10. The observed toxicity was equivalent to the same concentration of free DOX. With regard to the ongoing development in theranostic water-dispersible nanoformulations, the current formulation where Gd3+ ions are encapsulated by a macrocyclic chelator and covalently tethered to the hydrophilic head moiety of a lipid, is rather promising and holds great promise.

An approach to reduce the nonspecific cytotoxicity of chemotherapeutics has been put-forth using a biomimetic nanoabsorbent (NAb) as a detoxifying agent. The engineered NAb possesses a tunable drug absorption ability depending on the charge of the absorbing molecule, in which the cooperative absorption ability of the core and shell significantly reduces the cellular toxicity.

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 naive 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.

We engineered nanomedicine with the stealth corona made up of densely packed bone seeking ligand, alendronic acid. In a typical nanoconstruct, alendronic acid is conjugated with hydrophilic head moiety of phospholipid that has an ability to self-assemble with hydrophobic polymeric core through its hydrophobic long carbon-chain. Proposed nanomedicine has three distinct compartments namely; poly(l-lactic-co-glycolic acid) polymeric core acting as a drug reservoir and skeleton of the nanoconstruct, phospholipid monolayer covers the core acting as a diffusion barrier, and a densely packed alendronic acid corona acting as a stabilizer and targeting moiety. Thus engineered nanomedicine attain spherical entity with ~90 ± 6 nm having negative zeta potential, −37.7 ± 2 mV, and has an ability to load 7 ± 0.3 wt% of doxorubicin. In-vitro bone targeting efficiency of nanomedicine was studied using hydroxyapatite crystals as a bone model, and found significant accumulation of nanoparticle in the crystals. Moreover, cellular internalization studies with mouse osteosarcoma confirm the selectivity of nanomedicine when compared to its internalization in non-targeted mouse melanoma. This nanomedicine shows prolong stability in serum and deliver the drug into the cell exhibiting an IC50 of 3.7 μM. Given the strong interacting property of alendronic acid with bone, the proposed nanomedicine hold promises in delivering drug to bone microenvironment.