New erythrocyte-related delivery systems for biomedical applications

Glutaraldehyde modified red blood cells delivering artesunate to the liver as a dual therapeutic and prophylactic antimalaria strategy

Malaria can spread quickly in the population and develop rapidly. Patients with malaria usually die due to lack of timely and effective treatment. Artesunate (AS) is a highly effective and low-toxicity antimalarial drug, but its short half-life in the blood makes it difficult to control the malaria infection completely. Red blood cells (RBCs) have great biodegradability and can be employed to encapsulate various drugs. In this work, we employed RBCs as carriers to encapsulate AS and modified them with glutaraldehyde to construct an intelligent response drug delivery system (G-AS-RBCs) targeting the liver for antimalaria therapeutic and prophylactic activity. The G-AS-RBCs had a drug loading amount of 6.56 ± 0.14 mg 10-8 cells, suggesting excellent biocompatibility. G-AS-RBCs exhibited strong liver targeting efforts and can be maintained in the mice for at least 9 days, showing the potential for malaria prevention. The enrichment of AS in the liver was enhanced because of the natural liver targeting of erythrocytes and the enhancement of liver targeting by glutaraldehyde treatment. Furthermore, AS entrapped into RBCs also showed improved slow-release characteristics and achieved a better effect of inhibiting or killing the malaria parasite than free drugs. Therefore, this RBC-based strategy is expected to realize the prevention and treatment of malaria and has good application prospects.

Living Leukocyte-Based Drug Delivery Systems

Leukocytes play a vital role in immune responses, including defending against invasive pathogens, reconstructing impaired tissue, and maintaining immune homeostasis. When the immune system is activated in vivo, leukocytes accomplish a series of orderly and complex regulatory processes. While cancer and inflammation-related diseases like sepsis are critical medical difficulties plaguing humankind around the world, leukocytes have been shown to largely gather at the focal site, and significantly contribute to inflammation and cancer progression. Therefore, the living leukocyte-based drug delivery systems have attracted considerable attention in recent years due to the innate and specific targeting effect, low immunogenicity, improved therapeutic efficacy, and low reverse effect. In this review, the recent advances in the development of living leukocyte-based drug delivery systems including macrophages, neutrophils, and lymphocytes as promising treatment strategies for cancer and inflammation-related diseases are introduced. The advantages, current challenges, and limitations of these delivery systems are also discussed, as well as perspectives on the future development of precision and targeted therapy in the clinics are provided. Collectively, it is expected that such kind of living cell-based drug delivery system is promising to improve or even revolutionize the treatments of cancers and inflammation-related diseases in the clinics.

Erythrocyte-Inspired Functional Materials for Biomedical Applications

Erythrocytes are the most abundant cells in the blood. As the results of long-term natural selection, their specific biconcave discoid morphology and cellular composition are responsible for gaining excellent biological performance. Inspired by the intrinsic features of erythrocytes, various artificial biomaterials emerge and find broad prospects in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering. Here, a comprehensive review from the fabrication to the applications of erythrocyte-inspired functional materials is given. After summarizing the biomaterials mimicking the biological functions of erythrocytes, the synthesis strategies of particles with erythrocyte-inspired morphologies are presented. The emphasis is on practical biomedical applications of these bioinspired functional materials. The perspectives for the future possibilities of the advanced erythrocyte-inspired biomaterials are also discussed. It is hoped that the summary of existing studies can inspire researchers to develop novel biomaterials; thus, accelerating the progress of these biomaterials toward clinical biomedical applications.

Erythrocytes and Nanoparticles: New Therapeutic Systems

Nano-delivery systems represent one of the most studied fields, thanks to the associated improvement in the treatment of human diseases. The functionality of nanostructures is a crucial point, which the effectiveness of nanodrugs depends on. A hybrid approach strategy using synthetic nanoparticles (NPs) and erythrocytes offers an optimal blend of natural and synthetic materials. This, in turn, allows medical practitioners to exploit the combined advantages of erythrocytes and NPs. Erythrocyte-based drug delivery systems have been investigated for their biocompatibility, as well as the long circulation time allowed by specific surface receptors that inhibit immune clearance. In this review, we will discuss several methods—whole erythrocytes as drug carriers, red blood cell membrane-camouflaged nanoparticles and nano-erythrosomes (NERs)—while paying attention to their application and specific preparation methods. The ability to target cells makes erythrocytes excellent drug delivery systems. They can carry a wide range of therapeutic molecules while also acting as bioreactors; thus, they have many applications in therapy and in the diagnosis of many diseases.

Recent advances in functionalized nanomaterials for the diagnosis and treatment of bacterial infections

The growing problem of resistant infections due to antibiotic misuse is a worldwide concern that poses a grave threat to healthcare systems. Thus, it is necessary to discover new strategies to combat infectious diseases. In this review, we provide a selective overview of recent advances in the use of nanocomposites as alternatives to antibiotics in antimicrobial treatments. Metals and metal oxide nanoparticles (NPs) have been associated with inorganic and organic supports to improve their antibacterial activity and stability as well as other properties. For successful antibiotic treatment, it is critical to achieve a high drug concentration at the infection site. In recent years, the development of stimuli-responsive systems has allowed the vectorization of antibiotics to the site of infection. These nanomaterials can be triggered by various mechanisms (such as changes in pH, light, magnetic fields, and the presence of bacterial enzymes); additionally, they can improve antibacterial efficacy and reduce side effects and microbial resistance. To this end, various types of modified polymers, lipids, and inorganic components (such as metals, silica, and graphene) have been developed. Applications of these nanocomposites in diverse fields ranging from food packaging, environment, and biomedical antimicrobial treatments to diagnosis and theranosis are discussed.

Novel Fast and Reliable Method for Nano-Erythrosome Production Using Shear Force

Purpose

The production of nano-erythrosomes (NEs) by extrusion, which is considered the “gold standard”, has several disadvantages such as difficult equipment assembly, long procedure time, variable pressure, and problems with sterility. An alternative approach, using ultrasound probe, has been shown to overheat the sample and have suboptimal results compared to the extrusion method. In our study, we propose, develop, and test a new method for the fabrication of NEs based on shear force and then compare it to the “gold standard” extrusion approach.

Methods

The new method consists of mechanical shear force disruption of the hemoglobin-depleted erythrocyte ghost membranes, with the aid of a rotor stator based tissue homogenizer. Using the same batches of erythrocyte ghost membranes, we compared NEs produced by shear force to NEs produced by the well-established extrusion approach. NEs were characterized for yield, size, encapsulation efficiency, morphology, and stability by flow cytometry (FC), transmission electron microscopy (TEM), and zeta potential analysis.

Results

The shear force based process was easier to set up, significantly faster, had better sterility control, and decreased variability between batches. The shear force method generated NEs with the desired size distribution (particles diameter ~125 nm), which were morphologically and functionally equivalent to the NEs produced by extrusion. NEs produced by shear force were stable in terms of counts, size, and fluorescence intensity for 3 weeks at +4°C. Moreover, they showed colloidal stability and minimal influence to centrifugal stress, turbulence shock, and hemolytic potential.

Conclusion

The newly proposed shear force method allows faster, easier, and highly reproducible NEs production when compared to the conventional extrusion approach. The new setup allows simultaneous production of sterile batches of NEs, which have homogenous size distribution, good stability, and improved shelf life storage. The ability of the shear force method to process also high concentration samples indicates a future potential development of large-scale NEs production and industrial application, which has been a challenge for the extrusion method.

Surface-modified nanoerythrosomes for potential optical imaging diagnostics

Nanoerythrosomes (NERs), vesicle-like nanoparticles derived from red blood cells, represent a new and interesting vector for therapeutic molecules and imaging probes, mainly thanks to their high stability and excellent biocompatibility. Aiming to present a proof-of-concept of the use of NERs as diagnostic tools for in vitro/in vivo imaging purposes, we report here several functionalization routes to decorate the surfaces of NERs derived from bovine blood with two different fluorophores: 7-amino-4-methylcumarin and dibenzocyclooctinecyanine5.5. Notably, the fluorophores were cross-linked to the NERs surface with glutaraldehyde and, in the case of dibenzocyclooctinecyanine5.5, also using a click-chemistry route, termed strain-promoted azide-alkyne cycloaddition. The physicochemical characterization highlighted the high stability of the NERs derivatives in physiological conditions. Furthermore, the loading efficiency of the fluorophores on the NERs surface was evaluated using both UV-Vis spectroscopy and fluorescence microscopy.

Preparation and evaluation of long circulating erythrocyte membrane-cloaked anti-cancer drug delivery system

Recently, biomimetic hybrid drug delivery systems, especially erythrocyte membrane-based drug delivery systems, have been utilized to achieve high bioavailability, and biocompatibility, in the meantime, to reduce immunogenicity and effectively evade phagocytosis of the host immune system. Here, we developed a novel drug delivery system of red blood cell membrane-derived vesicles (RDVs) cloaked poly (acrylic acid)-cystamine hydrochloride-D-α-tocopherol succinate (PAAssVES) nanoparticles. The PAAssVES nanoparticles were prepared via emulsification and solvent volatilization method, followed by loading of the model anti-cancer drug, sorafenib (SFN). Then RDVs and SFN-PAAssVES nanoparticles were uniformly mixed and co-extruded through polycarbonate membrane. The prepared RDV-coated nanoparticles (RDV-NPs) had good stability, with a zeta potential of - 10.7 mV and particle size of 113.5 nm. MTT assay was used to analyze the effects of RDV-NPs on cell viability in two kinds of gastric cancer cell lines BGC-823 and MKN-45. The results showed that RDV-NPs significantly decreased cell viability. In vitro drug release investigation showed that RDV-NPs had good sustained release properties and the cumulative release was 71.5% in 72 h. In pharmacokinetic studies, SD male rats' intravenous injection with RDV-NP solution showed a more smooth plasma concentration-time profile. Compared with free SFN treatment and SFN-PAAssVES group, RDV-NPs enhanced the AUC by about 4.1-fold and 2.0-fold. The MRT and t_1/2 of RDV-NPs were increased to 23.670 ± 2.347 h and 24.450 ± 2.652 h. Our study demonstrated the promise of using RDV-NPs as a long circulating anti-cancer drug delivery system. Graphical abstract.