Membrane Fusion-Mediated Gold Nanoplating of Red Blood Cell: A Bioengineered CT-Contrast Agent

Aptamer-conjugated gold nanoparticles and their diagnostic and therapeutic roles in cancer

The burden of incidence rate and mortality of cancer is increasing rapidly, and the development of precise intervention measures for cancer detection and treatment will help reduce the burden and pain of cancer. At present, the sensitivity and specificity of tumor markers such as CEA and CA-125 used clinically are low, while PET, SPECT, and other imaging diagnoses with high sensitivity possess shortcomings, including long durations to obtain formal reports and the inability to identify the molecular pathological type of cancer. Cancer surgery is limited by stage and easy to recur. Radiotherapy and chemotherapy often cause damage to normal tissues, leading to evident side effects. Aptamers can selectively and exclusively bind to biomarkers and have, therefore, gained attention as ligands to be targeted for cancer detection and treatment. Gold nanoparticles (AuNPs) are considered as promising nano carriers for cancer diagnosis and treatment due to their strong light scattering characteristics, effective biocompatibility, and easy surface modification with targeted agents. The aptamer-gold nanoparticles targeting delivery system developed herein can combine the advantages of aptamers and gold nanoparticles, and shows excellent targeting, high specificity, low immunogenicity, minor side effects, etc., which builds a bridge for cancer markers to be used in early and efficient diagnosis and precise treatment. In this review, we summarize the latest progress in the application of aptamer-modified gold nanoparticles in cancer targeted diagnosis and delivery of therapeutic agents to cancer cells and emphasize the prospects and challenges of transforming these studies into clinical applications.

Surface Modification of Erythrocytes with Lipid Anchors: Structure-Activity Relationship for Optimal Membrane Incorporation, in vivo Retention, and Immunocompatibility

Red blood cells (RBCs) are natural carriers for sustained drug delivery, imaging, and in vivo sensing. One of the popular approaches to functionalize RBCs is through lipophilic anchors, but the structural requirements for anchor stability and in vivo longevity remain to be investigated. Using fluorescent lipids with the same cyanine 3 (Cy3) headgroup but different lipid chain and linker, the labeling efficiency of RBCs and in vivo stability are investigated. Short-chain derivatives exhibited better insertion efficiency, and mouse RBCs are better labeled than human RBCs. Short-chain derivatives demonstrate low retention in vivo. Derivatives with ester bonds are especially unstable, due to removal and degradation. On the other hand, long-chain, covalently linked derivatives show remarkably long retention and stability (over 80 days half life in the membrane). The clearance organs are liver and spleen with evidence of lipid transfer to the liver sinusoidal endothelium. Notably, RBCs modified with PEGylated lipid show decreased macrophage uptake. Some of the derivatives promote binding of antibodies in human plasma and mouse sera and modest increase in complement deposition and hemolysis, but these do not correlate with in vivo stability of RBCs. Ultra-stable anchors can enable functionalization of RBCs for drug delivery, imaging, and sensing.

Red Blood Cell Inspired Strategies for Drug Delivery: Emerging Concepts and New Advances

In the past five decades, red blood cells (RBCs) have been extensively explored as drug delivery systems due to their distinguishing potential in modulating the pharmacokinetic, pharmacodynamics, and biological activity of carried payloads. The extensive interests in RBC-mediated drug delivery technologies are in part derived from RBCs' unique biological features such as long circulation time, wide access to many tissues in the body, and low immunogenicity. Owing to these outstanding properties, a large body of efforts have led to the development of various RBC-inspired strategies to enable precise drug delivery with enhanced therapeutic efficacy and reduced off-target toxicity. In this review, we discuss emerging concepts and new advances in such RBC-inspired strategies, including native RBCs, ghost RBCs, RBC-mimetic nanoparticles, and RBC-derived extracellular vesicles, for drug delivery.

Research Progress of Cell Membrane Biomimetic Nanoparticles for Tumor Therapy

Nanoparticles have unique properties and high design flexibility, which are thought to be safe, site-specific, and efficient drug delivery systems. However, nanoparticles as exogenous materials can provide recognition and be eliminated by the body's immune system, which considerably restricts their applications. To overcome these drawbacks, natural cell membrane coating method has attracted great attention in the field of drug delivery systems, which can prolong nanoparticles blood circulation time and avoiding the capture as well as elimination by the body immune system. Biomimetic nanoparticles via a top-down approach can avoid the laborious group modified engineering and keep the integrity of cell membrane structure and membrane antigens, which can be endowed with unique properties, such as immune escape, longer blood circulation time, targeting delivery and controlling drugs sustain-release. At the present research, erythrocyte membrane, cancer cell membrane, platelet membrane, lymphocyte membrane and hybrid membrane have been successfully coated into the surface of nanoparticles to achieve biological camouflage. Thus, integrating various kinds of cell membranes and nanoparticles into one system, the biomimetic nanoparticles can inherit unique biofunction and drug delivery properties to exhibit tumor targeting-delivery and antitumor outcomes. In this article, we will discuss the prospects and challenges of some basic cell membrane cloaking nanoparticles as a drug delivery system for cancer therapy.

Membrane Cholesterol Enrichment of Red Blood Cell-Derived Microparticles Results in Prolonged Circulation

Particles fabricated from red blood cells (RBCs) can serve as vehicles for delivery of various biomedical cargos. Flipping of phosphatidylserine (PS) from the inner to the outer membrane leaflet normally occurs during the fabrication of such particles. PS externalization is a signal for phagocytic removal of the particles from circulation. Herein, we demonstrate that membrane cholesterol enrichment can mitigate the outward display of PS on microparticles engineered from RBCs. Our in-vitro results show that the phagocytic uptake of cholesterol-enriched particles by murine macrophages takes place at a lowered rate, resulting in reduced uptake as compared to RBC-derived particles without cholesterol enrichment. When administered via tail-vein injection into healthy mice, the percent of injected dose (ID) per gram of extracted blood for cholesterol-enriched particles was ∼1.5 and 1.8 times higher than the particles without cholesterol enrichment at 4 and 24 h, respectively. At 24 h, ∼43% ID/g of the particles without cholesterol enrichment was eliminated or metabolized while ∼94% ID/g of the cholesterol-enriched particles were still retained in the body. These results indicate that membrane cholesterol enrichment is an effective method to reduce PS externalization on the surface of RBC-derived particles and increase their longevity in circulation.

Recent progress in the applications of gold-based nanoparticles towards tumor-targeted imaging and therapy

Cancer death rate remains high all over the world, scientists are paying increasing attention to meet the requirements for precise diagnosis and therapy. Therefore, early diagnosis and active treatment can effectively improve the five-year survival rate of patients. In recent years, gold-based nanomaterials have received increasing attention in medical fields due to their excellent biocompatibility, low toxicity and unique properties. In addition, because of the inherent nature of gold nanomaterials including for computed tomography (CT), fluorescence/optical imaging (FI/OI), surface enhanced Raman spectroscopy imaging (SERS), photoacoustic imaging (PAI) and photothermal therapy (PTT), various gold nanomaterials were developed as theranostic nanoplatforms. In this review, we summarized the latest developments of nanomaterials in imaging and combined therapy, and the prospects for the future application of gold-based theranostic nanoplatforms were also proposed.

We summarize the latest developments of gold nanomaterials in imaging and combined therapy as well as prospects for the future application of gold-based theranostic nanoplatforms.

Re-engineered imaging agent using biomimetic approaches

Recent progress in biomedical technology, the clinical bioimaging, has a greater impact on the diagnosis, treatment, and prevention of disease, especially by early intervention and precise therapy. Varieties of organic and inorganic materials either in the form of small molecules or nano-sized materials have been engineered as a contrast agent (CA) to enhance image resolution among different tissues for the detection of abnormalities such as cancer and vascular occlusion. Among different innovative imaging agents, contrast agents coupled with biologically derived endogenous platform shows the promising application in the biomedical field, including drug delivery and bioimaging. Strategy using biocomponents such as cells or products of cells as a delivery system predominantly reduces the toxic behavior of its cargo, as these systems reduce non-specific distribution by navigating its cargo toward the targeted location. The hypothesis is that depending on the original biological role of the naïve cell, the contrast agents carried by such a system can provide corresponding natural designated behavior. Therefore, by combining properties of conventional synthetic molecules and nanomaterials with endogenous cell body, new solutions in the field of bioimaging to overcome biological barriers have been offered as innovative bioengineering. In this review, we will discuss the engineering of cell and cell-derived components as a delivery system for various contrast agents to achieve clinically relevant contrast for diagnosis and study underlining mechanism of disease progression. This article is categorized under: Nanotechnology Approaches to Biology > Cells at the Nanoscale Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Recent advances in cell membrane camouflage-based biosensing application

Cell membrane, a semi-permeable membrane composed of phospholipid bilayers, is a natural barrier to prevent extracellular substances from freely entering the cell. Cell membrane with selective permeability and fluidity ensures the relative stability of the intracellular environment and enables various biochemical reactions to smoothly operate in an orderly manner. Inspired by the natural composition and transport process, various cell membranes and synthetic bionic films as the mimics of cell membranes have emerged as appealing camouflage materials for biosensing applications. The membranes are devoted to surface modification and substance delivery, and realize the detection or in situ analysis of multiple biomarkers, such as glucose, nucleic acids, virus, and circulating tumor cells. In this review, we summarize the recent advances in cell membrane camouflage-based biosensing applications, mainly focusing on the use of the membranes extracted from natural cells (e.g., blood cells and cancer cells) as well as biomimetic membranes. Materials and surfaces camouflaged with cell membranes are shown to have superior stability and biocompatibility as well as intrinsic properties of original cells, which greatly facilitate their use in biosensing. In specific, camouflage with blood cell membranes bestows low immunogenicity and prolonged blood circulation time, camouflage with cancer cell membranes provides homologous targeting ability, and camouflage with biomimetic membranes endows considerable plasticity for functionalization. Further research is expected to focus on the deeper understanding of cell-specific properties of membranes and the exploration of hybrid membranes, which might provide new development opportunities for cell membrane camouflage-based biosensing application.

Re-engineering a Liposome with Membranes of Red Blood Cells for Drug Delivery and Diagnostic Applications

Red blood cells (RBCs) make up the overwhelming majority of cells in the vascular system, spending most of their lives wandering the vast network of vessels that permeate every tissue of our bodies. Therefore, the delivery of any class of therapeutic agent that must stay in the circulatory system may benefit from being carried by RBCs. Toward this direction, we have re-engineered a synthetic liposome with the membranes of RBCs and incorporated a magnetic resonance imaging (MRI) contrast agent gadolinium along with the chemotherapeutic drug doxorubicin (DOX) to form a biomimetic liposome (BML). The BMLs proposed herein consist of biocompatible/biodegradable synthetic phospholipids, which include 1,2-distearoyl-sn-glycero-3-phosphoglycerol, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine, and gadolinium-conjugated lipids. These synthetic phospholipids have been fused with a natural RBC membrane and are loaded with DOX using the extrusion technique. BMLs were characterized for their physicochemical properties, stability, fusogenic (between synthetic and natural lipid from RBC), magnetic, drug loading, biocompatibility, and cytotoxicity properties. BMLs had a hydrodynamic diameter of 180 ± 20 nm with a negative surface charge of 29 ± 2 mV. The longitudinal relaxivity (r₁) of BML is 3.71 mM^-1 s^-1, which is comparable to the r₁ of commercial contrast agent, Magnevist. In addition, DOX-loaded BML showed a cytotoxicity pattern similar to that of free DOX. These results showed the potential of using the proposed BML system for both MRI-based diagnostic applications and drug delivery platforms.

Cell primitive-based biomimetic functional materials for enhanced cancer therapy

Cell primitive-based functional materials that combine the advantages of natural substances and nanotechnology have emerged as attractive therapeutic agents for cancer therapy. Cell primitives are characterized by distinctive biological functions, such as long-term circulation, tumor specific targeting, immune modulation etc. Moreover, synthetic nanomaterials featuring unique physical/chemical properties have been widely used as effective drug delivery vehicles or anticancer agents to treat cancer. The combination of these two kinds of materials will catalyze the generation of innovative biomaterials with multiple functions, high biocompatibility and negligible immunogenicity for precise cancer therapy. In this review, we summarize the most recent advances in the development of cell primitive-based functional materials for cancer therapy. Different cell primitives, including bacteria, phages, cells, cell membranes, and other bioactive substances are introduced with their unique bioactive functions, and strategies in combining with synthetic materials, especially nanoparticulate systems, for the construction of function-enhanced biomaterials are also summarized. Furthermore, foreseeable challenges and future perspectives are also included for the future research direction in this field.

Erythrocytes as Carriers: From Drug Delivery to Biosensors

Drug delivery using natural biological carriers, especially erythrocytes, is a rapidly developing field. Such erythrocytes can act as carriers that prolong the drug's action due to its gradual release from the carrier; as bioreactors with encapsulated enzymes performing the necessary reactions, while remaining inaccessible to the immune system and plasma proteases; or as a tool for targeted drug delivery to target organs, primarily to cells of the reticuloendothelial system, liver and spleen. To date, erythrocytes have been studied as carriers for a wide range of drugs, such as enzymes, antibiotics, anti-inflammatory, antiviral drugs, etc., and for diagnostic purposes (e.g. magnetic resonance imaging). The review focuses only on drugs loaded inside erythrocytes, defines the main lines of research for erythrocytes with bioactive substances, as well as the advantages and limitations of their application. Particular attention is paid to in vivo studies, opening-up the potential for the clinical use of drugs encapsulated into erythrocytes.

Erythrocyte membrane concealed paramagnetic polymeric nanoparticle for contrast-enhanced magnetic resonance imaging

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.

Strategic reconstruction of macrophage-derived extracellular vesicles as a magnetic resonance imaging contrast agent

Reconstruction of extracellular vesicles with imaging agents allows precise downstream analysis using clinical imaging modalities, for example, MRI. This will further improve the biocompatibility of agents thereby enhancing clinical investigations.

Integration of gadolinium in nanostructure for contrast enhanced-magnetic resonance imaging

Magnetic resonance imaging (MRI) is a routinely used imaging technique in medical diagnostics, which is further enhanced with the use of contrast agents (CAs). The most commonly used CAs are gadolinium-based contrast agents (GBCAs), in which gadolinium (Gd) is chelated with organic chelating agents (linear or cyclic). However, the use of GBCA is related to toxic side effect due to the release of free Gd³⁺ ions from the chelating agents. The repeated use of GBCAs has led to Gd deposition in various major organs including bone, brain, and kidneys. As a result, the use of GBCA has been linked to the development of nephrogenic systemic fibrosis (NSF). Due to the GBCA associated toxicities, some clinically approved GBCAs have been limited or revoked recently. Therefore, there is an urgent need for the development of new strategies to chelate and stabilize Gd³⁺ ions for contrast enhancement, safety profile, and selective imaging of a pathological site. Toward this endeavor, GBCAs have been engineered using different nanoparticulate systems to improve their stability, biocompatibility, and pharmacokinetics. Throughout this review, some of the important strategies for engineering small molecular Gd³⁺ chelates into a nanoconstruct is discussed. We focus on the development of GBCAs as liposomes, mesoporous silica nanoparticles (MSNs), polymeric nanocarriers, and plasmonic nanoparticles-based design strategies to improve safety and contrast enhancement for contrast enhanced-magnetic resonance imaging (Ce-MRI). We also discuss the in-vitro/in-vivo properties of strategically designed nanoscale MRI CAs, its potentials, and limitations. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Diagnostic Tools > Diagnostic Nanodevices Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials.

Macrophage-derived exosome-mimetic hybrid vesicles for tumor targeted drug delivery

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.

Regulating intracellular fate of siRNA by endoplasmic reticulum membrane-decorated hybrid nanoplexes

Most cationic vectors are difficult to avoid the fate of small interfering RNA (siRNA) degradation following the endosome-lysosome pathway during siRNA transfection. In this study, the endoplasmic reticulum (ER) membrane isolated from cancer cells was used to fabricate an integrative hybrid nanoplexes (EhCv/siRNA NPs) for improving siRNA transfection. Compared to the undecorated Cv/siEGFR NPs, the ER membrane-decorated EhCv/siRNA NPs exhibits a significantly higher gene silencing effect of siRNA in vitro and a better antitumor activity in nude mice bearing MCF-7 human breast tumor in vivo. Further mechanistic studies demonstrate that functional proteins on the ER membrane plays important roles on improving cellular uptake and altering intracellular trafficking pathway of siRNA. It is worth to believe that the ER membrane decoration on nanoplexes can effectively transport siRNA through the endosome-Golgi-ER pathway to evade lysosomal degradation and enhance the silencing effects of siRNA.

Biomimetic surface modification of discoidal polymeric particles

The rationale for the design of drug delivery nanoparticles is traditionally based on co-solvent self-assembly following bottom-up approaches or in combination with top-down approaches leading to tailored physiochemical properties to regulate biological responses. However, the optimal design and control of material properties to achieve specific biological responses remain the central challenge in drug delivery research. Considering this goal, we herein designed discoidal polymeric particles (DPPs) whose surfaces are re-engineered with isolated red blood cell (RBC) membranes to tailor their pharmacokinetics. The RBC membrane-coated DPPs (RBC-DPPs) were found to be biocompatible in cell-based in vitro experiments and exhibited extended blood circulation half-life. They also demonstrated unique kinetics at later time points in a mouse model compared to that of bare DPPs. Our results suggested that the incorporation of biomimicry would enable the biomimetic particles to cooperate with systems in the body such as cells and biomolecules to achieve specific biomedical goals.

The influence of polyethylene glycol passivation on the surface plasmon resonance induced photothermal properties of gold nanorods

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.

Erythrocyte-Derived Optical Nanoprobes Doped with Indocyanine Green-Bound Albumin: Material Characteristics and Evaluation for Cancer Cell Imaging

Nanosize structures activated by near-infrared (NIR) photoexcitation can provide an optical platform for the image-guided removal of small tumor nodules. We have engineered nanoparticles derived from erythrocytes that can be doped with NIR fluorophore indocyanine green (ICG). We refer to these constructs as NIR erythrocyte-derived transducers (NETs). The objective of this study was to determine if ICG-bound albumin (IbA), as the doping material, could enhance the fluorescence emission of NETs, and evaluate the capability of these nanoprobes in imaging cancer cells. Erythrocytes were isolated from bovine whole blood and depleted of hemoglobin to form erythrocyte ghosts (EGs). EGs were then extruded through nanosize porous membranes in the presence of 10-100 μm ICG or Iba (1:1 molar ratio) to form ICG- or IbA-doped NETs. The resulting nanosize constructs were characterized for their diameters, zeta-potentials, absorption, and fluorescence emission spectra. We used fluorescence microscopic imaging to evaluate the capability of the constructs in imaging SKOV3 ovarian cancer cells. Based on dynamic light-scattering measurements, ICG- and IbA-doped NETs had similar diameter distributions (Z-average diameter of 236 and 238 nm, respectively) in phosphate-buffered saline supplemented with 10% fetal bovine serum, which remained nearly constant over the course of 2 h at 37 °C. Despite a much-lower loading efficiency of IbA (∼0.7-8%) as compared to ICG (10-45%), the integrated normalized fluorescence emission of IbA-NETs was 2- to 6-fold higher than ICG-doped NETs. IbA-NETs also demonstrated an enhanced capability in fluorescence imaging of SKOV3 ovarian cancer cells, and can serve as potentially effective nanoprobes for the fluorescence imaging of cancerous cells.

Natural killer cell membrane infused biomimetic liposomes for targeted tumor therapy

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.

Molecular and Biocompatibility Characterization of Red Blood Cell Membrane Targeted and Cell-Penetrating-Peptide-Modified Polymeric Nanoparticles

Red blood cells (RBCs) express a variety of immunomodulatory markers that enable the body to recognize them as self. We have shown that RBC membrane glycophorin A (GPA) receptor can mediate membrane attachment of protein therapeutics. A critical knowledge gap is whether attaching drug-encapsulated nanoparticles (NPs) to GPA and modification with cell-penetrating peptide (CPP) will impact binding, oxygenation, and the induction of cellular stress. The objective of this study was to formulate copolymer-based NPs containing model fluorescent-tagged bovine serum albumin (BSA) with GPA-specific targeting ligands such as ERY1 (ENPs), single-chain variable antibody (scFv TER-119, SNPs), and low-molecular-weight protamine-based CPP (LNPs) and to determine their biocompatibility using a variety of complementary high-throughput in vitro assays. Experiments were conducted by coincubating NPs with RBCs at body temperature, and biocompatibility was evaluated by Raman spectroscopy, hemolysis, complement lysis, and oxidative stress assays. Data suggested that LNPs effectively targeted RBCs, conferring 2-fold greater uptake in RBCs compared to ENPs and SNPs. Raman spectroscopy results indicated no adverse effect of NP attachment or internalization on the oxygenation status of RBCs. Cellular stress markers such as glutathione, malondialdehyde, and catalase were within normal limits, and complement-mediated lysis due to NPs was negligible in RBCs. Under the conditions tested, our data demonstrates that molecular targeting of the RBC membrane is a feasible translational strategy for improving drug pharmacokinetics and that the proposed high-throughput assays can prescreen diverse NPs for preclinical and clinical biocompatibility.