Erythrocytes as Carriers: From Drug Delivery to Biosensors

Sonosensitizers for Sonodynamic Therapy: Current Progress and Future Perspectives

Sonodynamic therapy (SDT) is a novel non-invasive treatment method that combines low-intensity ultrasound and sonosensitizers. Compared with photodynamic therapy, SDT has the advantages of deeper tissue penetration, higher accuracy and fewer adverse reactions. Sonosensitizers are essential for the efficacy of SDT. Sonosensitizers have the advantages of clear structure, easy monitoring, evaluation of drug metabolism and clinical transformation, etc. Notably, biochemical techniques can be used in the field of sonosensitizers and SDT to overcome inherent barriers and achieve sustainable innovation. This article first summarizes the molecular mechanism of SDT, focusing on organic sonosensitizers, inorganic nano-sonosensitizers and multi-functional drug delivery systems with targeting, penetration and imaging functions after a series of modifications. This review provides ideas and references for the design of sonosensitizers and SDT and promotes their future transformation into clinical applications.

RBCs as a Bioinspired Drug Delivery System for Co-delivery of Irinotecan and Nanoalumina Enhances Colorectal Cancer Therapy

Colorectal cancer (CRC) is a malignant epithelial tumor with high morbidity and mortality. In CRC treatment, irinotecan (CPT-11) as a chemotherapeutic drug is widely applied. However, its half-life is short, leading to large dosages and severe side effects. Red blood cells (RBCs) are biocompatible drug carriers with high capacity, avoiding premature drug degradation and achieving slow drug release. Nanoalumina (AN) is an emerging immune adjuvant that can enhance the immune response. Here, we used RBCs as carriers and absorbed AN to construct AN-CPT-11-RBCs. CPT-11 would induce tumor cell death, releasing much tumor antigen, while AN would activate immune cells to recognize newly released antigens and induce lymphocyte proliferation, enhancing the antitumor effect simultaneously. With loading amounts of 4 mg of CPT-11 and 3 mg of AN per 109 RBCs, AN-CPT-11-RBCs had similar properties to natural RBCs. In vivo, AN-CPT-11-RBCs could circulate for 9 days and stimulate the proliferation of lymphocytes in the spleen and tumor tissue, having a higher tumor growth inhibition rate of 74.01% and a lower frequency of administration. In conclusion, AN-CPT-11-RBCs attain the co-delivery of CPT-11 and AN for the synergistic treatment of CRC.

Metallofullerenol Gd@C82(OH)22 preserves human erythrocyte plasma membrane integrity from AAPH-induced oxidative stress: Molecular mechanisms and antioxidant activity

Metallofullerenols and fullerenols have attracted attention due to their remarkable ability to interact with various biologically relevant molecules, paving the way for biomedical applications, ranging from medical imaging techniques to drug carriers, acting with increased efficiency and reduced side effects. In this work, we investigated the effects of two fullerene derivatives, Gd@C82(OH)22 and C70(OH)12, on erythrocyte membrane components under oxidative stress conditions induced by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) as a source of peroxyl radicals. The results demonstrated that gadolinium encapsulation within the fullerene cage enhanced the electron affinity of Gd@C82(OH)22, resulting in stronger antioxidant activity. Gd@C82(OH)22 formed a protective hydrophilic layer at the lipid-water interface, effectively preventing lipid peroxidation, oxidative protein damage, and potassium leakage, outperforming C70(OH)12. Both compounds improved membrane fluidity, but Gd@C82(OH)22 exhibited superior preservation of the erythrocyte lipid bilayer and protein function. Additionally, Gd@C82(OH)22 maintained the anion exchange function of band 3 protein, which is critical for ionic homeostasis, by preventing oxidation-induced aggregation and preserving thiol groups. Despite its limited membrane penetration, Gd@C82(OH)22 stabilized membrane components through hydrogen bonding, which indirectly enhanced membrane stiffness and fluidity under oxidative stress. This external protection of membrane integrity reduced the risk of lipid peroxidation and oxidative damage to erythrocyte proteins. In contrast, C70(OH)12, while effective in protecting membrane lipids, was less effective in preserving protein structure. These findings highlight the unique protective properties of Gd@C82(OH)22, attributed to polarization effects induced by the encapsulated Gd atom. This study indicates that metallofullerenols, such as Gd@C82(OH)22, may have therapeutic potential in mitigating oxidative damage.

Biomechanical and Functional Features of the Carrier Erythrocytes Prolonging Circulation Time of Biotherapeutic Targeted to Glycophorin A

Red blood cells (RBCs) serve as natural transporters and can be modified to enhance the pharmacokinetics and pharmacodynamics of a protein cargo. Affinity targeting of Factor IX (FIX) to the RBC membrane is a promising approach to improve the (pro)enzyme's pharmacokinetics. For RBC targeting, purified human FIX was conjugated to the anti-mouse glycophorin A monoclonal antibody Ter119. The goal of this study was to characterize the activity of the FIX-Ter119 conjugate and efficacy of its loading on RBCs, as well as to investigate the biodistribution, pharmacokinetics, and various biological properties of the loaded RBCs. Mouse RBCs were incubated with the Ter119-FIX conjugate, where adding 10,000 molecules per RBC resulted in 37% binding (4K/RBC), and 50,000 molecules per RBC resulted in 34% binding (17K/RBC). The pharmacokinetics (PK) profile showed that more than 90% of the Ter119-FIX conjugate was associated with RBCs and circulated stably bound to the RBCs for 24 h, increasing the area under the PK curve 7.6 times vs free FIX. Ter119-FIX loaded RBCs have specific procoagulant FIXa activity, including promotion of thrombin generation and acceleration of clotting in FIX-deficient plasma. Morphological characterization shows that Ter119-FIX-loaded RBCs undergo a shape change, with an increased fraction of echinocytes and spheroidal RBCs. Ektacytometry and electron microscopy assessment of RBC compressibility reveal a dose-dependent reduction in the deformability of RBCs loaded with Ter119-FIX. In conclusion, RBCs loaded with Ter119-FIX have the potential to serve as prohemostatic agents, but their reduced deformability warrants further engineering of Ter119-FIX to improve the safety profile.

Biohybrid nano-platforms manifesting effective cancer therapy: Fabrication, characterization, challenges and clinical perspective

Nanotechnology-based delivery systems have brought a paradigm shift in the management of cancer. However, the main obstacles to nanocarrier-based delivery are their limited circulation duration, excessive immune clearance, inefficiency in interacting effectively in a biological context and overcoming biological barriers. This demands effective engineering of nanocarriers to achieve maximum efficacy. Nanocarriers can be maneuvered with biological components to acquire biological identity for further regulating their biodistribution and cell-to-cell cross-talk. Thus, the integration of synthetic and biological components to deliver therapeutic cargo is called a biohybrid delivery system. These delivery systems possess the advantage of synthetic nanocarriers, such as high drug loading, engineerable surface, reproducibility, adequate communication and immune evasion ability of biological constituents. The biohybrid delivery vectors offer an excellent opportunity to harness the synergistic properties of the best entities of the two worlds for improved therapeutic outputs. The major spotlights of this review are different biological components, synthetic counterparts of biohybrid nanocarriers, recent advances in hybridization techniques, and the design of biohybrid delivery systems for cancer therapy. Moreover, this review provides an overview of biohybrid systems with therapeutic and diagnostic applications. In a nutshell, this article summarizes the advantages and limitations of various biohybrid nano-platforms, their clinical potential and future directions for successful translation in cancer management.

Differentiating erythroblasts adapt to mechanical stimulation by upregulation of cholesterol biosynthesis via S1P/SREBP-induced HMGCR expression

Understanding how mechanical stress affects erythropoiesis is crucial to produce transfusable erythrocytes in fluid-turbulent bioreactors. We investigated the effects of shear-stress on differentiating CD49d+CD235a+ primary human erythroblasts (EBL) at molecular, cellular, and functional level. Shear-stress, at differentiation onset, enhanced EBL maturation and induced upregulation of genes regulating cholesterol/lipids biosynthesis, causing changes in cell lipid composition. Of note, the osmotic resistance, and the expression of 3-Hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the rate-limiting enzyme of the cholesterol biosynthesis pathway, were higher in dynamic cultures. Inhibition of the S1P-induced proteolytic cleavage, activating SREBPs, led to abrogation of HMCGR expression, and loss of EBL in dynamic cultures, similar to lovastatin administration. This data reveals a role for the S1P-SREBP-HMGCR-axis in the regulation of shear-stress induced adaptation during erythropoiesis, shedding light into mechanisms that will assist the upscaling of erythroid differentiation into bioreactors. Moreover, as shear-stress on hematopoietic cells occurs within the bone-marrow, these results introduce a novel signalling axis in the transduction pathways controlling erythropoiesis.

Tumor cell membrane-based vaccines: A potential boost for cancer immunotherapy

Because therapeutic cancer vaccines can, in theory, eliminate tumor cells specifically with relatively low toxicity, they have long been considered for application in repressing cancer progression. Traditional cancer vaccines containing a single or a few discrete tumor epitopes have failed in the clinic, possibly due to challenges in epitope selection, target downregulation, cancer cell heterogeneity, tumor microenvironment immunosuppression, or a lack of vaccine immunogenicity. Whole cancer cell or cancer membrane vaccines, which provide a rich source of antigens, are emerging as viable alternatives. Autologous and allogenic cellular cancer vaccines have been evaluated as clinical treatments. Tumor cell membranes (TCMs) are an intriguing antigen source, as they provide membrane-accessible targets and, at the same time, serve as integrated carriers of vaccine adjuvants and other therapeutic agents. This review provides a summary of the properties and technologies for TCM cancer vaccines. Characteristics, categories, mechanisms, and preparation methods are discussed, as are the demonstrable additional benefits derived from combining TCM vaccines with chemotherapy, sonodynamic therapy, phototherapy, and oncolytic viruses. Further research in chemistry, biomedicine, cancer immunology, and bioinformatics to address current drawbacks could facilitate the clinical adoption of TCM vaccines.

Recent advances with erythrocytes as therapeutics carriers

Erythrocytes have gained popularity as a natural option for in vivo drug delivery due to their advantages, which include lengthy circulation times, biocompatibility, and biodegradability. Consequently, the drug's pharmacokinetics and pharmacodynamics in red blood cells can be considerably up the dosage. Here, we provide an overview of the erythrocyte membrane's structure and discuss the characteristics of erythrocytes that influence their suitability as carrier systems. We also cover current developments in the erythrocyte-based nanocarrier, which could be used for both active and passive targeting of disease tissues, particularly those of the reticuloendothelial system (RES) and cancer tissues. We also go over the most recent discoveries about the in vivo and in vitro uses of erythrocytes for medicinal and diagnostic purposes. Moreover, the clinical relevance of erythrocytes is discussed in order to improve comprehension and enable the potential use of erythrocyte carriers in the management of various disorders.

Platelet-cloaked alginate-poly (β-amino ester) a novel platform bioinspired polyelectrolyte nanoparticle for targeted delivery of carboplatin in breast cancer: An in vitro/in vivo study

Triple-negative breast cancer (TNBC) has poor prognosis. Carboplatin (Crb) is a widely used chemotherapeutic agent, in TNBC but with serious systemic toxicity and poor tumor targeting. Bioinspired drug-loaded platelets (Plt) and Plt-coated nanocarriers evade macrophage phagocytosis by membrane proteins like CD47. The goal of this study was preparation of a novel alginate-poly (β-amino ester) (PβAE) nanoparticles (NPs) for targeted delivery of Crb to TNBC cells by developing and comparison of two bioinspired carriers of Plt membrane (PltM) coated Crb-loaded alginate-poly (β-amino ester) nanoparticles (PltM@Crb-PβAE-ALG NPs) and Plt loaded Crb (Plt@Crb). The NPs were prepared by ionic gelation and subsequently were coated by platelet membrane using ultra-sonication method. The loading efficiency, release profile, and in vitro cytotoxicity of both formulations were evaluated on HUVEC and 4 T1 cells. Additionally, the in vivo tumor targeting, therapeutic efficacy, and organ toxicity of the two formulations were assessed in a murine tumor model. Results showed both Plt@Crb and (PltM@Crb-PβAE-ALG NPs) exhibited high drug loading efficiency, sustained release, enhanced cytotoxicity against 4 T1 cells, and decreased cytotoxicity in normal cells (HUVEC) in vitro. In vivo studies revealed that although both formulations considerably improved tumor inhibition compared to free Crb, but the PltM@Crb-PβAE-ALG NPs demonstrated superior cytotoxicity and therapeutic efficacy, thanks to improved Crb's internalization efficiency, enhanced stability, and controlled release properties.

Pharmacokinetics and fate of free and encapsulated IRD800CW-labelled human BChE intravenously administered in mice

Human butyrylcholinesterase (BChE) is an efficient bioscavenger of toxicants. Highly purified BChE was labelled with the near infrared fluorescent IRDye800CW. The goal was to determine the pharmacokinetics and fate of enzyme in mice. BChE-IRDye800CW was encapsulated in polyethylene glycol-polypropylene sulfide-based spherical polymersome nanoreactors with the following characteristics: 140 nm diameter, ξ = -6 mV, PDI ≤ 0.2, 1 year stability. Encapsulation did not alter the functional properties of BChE. Free and encapsulated enzyme were injected intravenously to CD-1 mice (single dose of enzyme 1.5 mg/kg and PEG-PPS polymersomes 25 mg/kg) and were analyzed for 8 days using an in vivo imaging system. Results showed that the pharmacokinetic distribution α-phase of encapsulated BChE (t1/2 = 17.6 h) was longer than for free enzyme (t1/2 = 6.6 h). The mean half-time for elimination β-phase was 2-time longer for encapsulated enzyme than for free enzyme (150 vs 72 h). Transient changes in infrared fluorescence in organs showed that BChE is eliminated from liver. However, free and encapsulated enzymes were cleared via different pathways. This first study of pharmacokinetics and fate of BChE encapsulated in polymersomes initiates research of new formulations of bioscavengers aimed at increasing the residence time of enzymes in the blood stream.

Proteolysis Assays With Conserved or Aminofluorescein-Labeled Red Blood Cells

Backgrounds: Various physiological functions and reaction cascades, as well as disease progression in the living systems, are controlled by the activity of specific proteolytic enzymes. We conducted the study to evaluate protease activity by assessing peptide fragments from either conserved or labeled red blood cells (RBCs) with aminofluorescein (AF) in the reaction media. Methods: RBCs were incubated in media containing trypsin. Subsequently, the concentration of peptide fragments in the reaction media, resulted by the digestion with trypsin from conserved cells, was estimated by 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA) as an amine-reactive fluorogenic reagent. In a second approach, we conjugated AF to the conserved RBCs and then exposed AF-labeled RBCs to trypsin. This was followed by directly measuring the fluorescence intensity (FI) in the reaction media to estimate the concentration of AF-labeled peptide fragments resulting from the enzyme's activity. Results: Show a concentration- and time-dependent increase in FIs, reflecting the activity of trypsin as a proteolytic enzyme. The FIs increased significantly by 4 to 5 folds in samples treated with different enzyme concentrations, and by over 11 folds after 2 h incubation in media containing a 50 μL trypsin, as evidenced by CBQCA assays. Conclusion: These fast and affordable approaches could be applied with high reliability for the general estimation of protease activity in samples and customized for diagnostic purposes and prognostic evaluation in various diseases.

RBC-hitchhiking PLGA nanoparticles loading β-glucan as a delivery system to enhance in vitro and in vivo immune responses in mice

Red blood cells (RBCs) naturally trap some bacterial pathogens in the circulation and kill them by oxidative stress. Following neutralization, the bacteria are presented to antigen-presenting cells in the spleen by the RBCs. This ability of RBCs has been harnessed to develop a system where they play a crucial role in enhancing the immune response, offering a novel approach to enhance the body's immunity. In this work, a conjugate, G-OVA, was formed by connecting β-glucan and OVA through a disulfide bond. Poly (lactic-co-glycolic acid) (PLGA) was then employed to encapsulate G-OVA, yielding G-OVA-PLGA. Finally, the nanoparticles were adsorbed onto RBCs to develop G-OVA-PLGA@RBC. The results demonstrated that the delivery of nanoparticles by RBCs enhanced the antibody response to antigens both in vitro and in vivo. The objective of this study was to investigate the increased immune activity of G-OVA-PLGA nanoparticles facilitated by RBCs transportation and to elucidate some of its underlying mechanisms. These findings are anticipated to contribute valuable insights for the development of efficient and safe immune enhancers.

Exploring Therapeutic Potential of Catalase: Strategies in Disease Prevention and Management

The antioxidant defense mechanisms play a critical role in mitigating the deleterious effects of reactive oxygen species (ROS). Catalase stands out as a paramount enzymatic antioxidant. It efficiently catalyzes the decomposition of hydrogen peroxide (H2O2) into water and oxygen, a potentially harmful byproduct of cellular metabolism. This reaction detoxifies H2O2 and prevents oxidative damage. Catalase has been extensively studied as a therapeutic antioxidant. Its applications range from direct supplementation in conditions characterized by oxidative stress to gene therapy approaches to enhance endogenous catalase activity. The enzyme's stability, bioavailability, and the specificity of its delivery to target tissues are significant hurdles. Furthermore, studies employing conventional catalase formulations often face issues related to enzyme purity, activity, and longevity in the biological milieu. Addressing these challenges necessitates rigorous scientific inquiry and well-designed clinical trials. Such trials must be underpinned by sound experimental designs, incorporating advanced catalase formulations or novel delivery systems that can overcome existing limitations. Enhancing catalase's stability, specificity, and longevity in vivo could unlock its full therapeutic potential. It is necessary to understand the role of catalase in disease-specific contexts, paving the way for precision antioxidant therapy that could significantly impact the treatment of diseases associated with oxidative stress.

Exogenous polyserine fibrils change membrane properties of phosphatidylcholine-liposome and red blood cells

The causative genes for neurodegenerative polyglutamine (polyQ) diseases produce homopolymeric polyglutamine (polyQ), polyserine (polyS), polyalanine (polyA), polycysteine (polyC), and polyleucine (polyL) sequences by repeat-associated non-AUG (RAN) translation. The cytotoxicity of the intracellular polyQ and RAN products has been extensively investigated. However, little is known about the toxicity of the extracellular polyQ and RAN products on the membranes of viable cells. Because polyQ aggregates induce a deflated morphology of a model membrane, we hypothesized that extracellular polyQ and RAN products might affect the membrane properties of viable cells. In this study, we demonstrated that exogenous polyS fibrils but not polyS or polyQ non-fibril aggregates altered the thermal phase transition behavior of a model membrane composed of a phosphatidylcholine bilayer using differential scanning calorimetry. PolyS fibrils induced morphological changes in viable red blood cells (RBCs). However, both polyS and polyQ non-fibril aggregates had no effects on RBCs. These results highlight the possibility that extracellular fibrils generated from RAN products may alter the properties of neuronal cell membranes, which may contribute to changes in the brain pathology.

The future of blood services amid a tight balance between the supply and demand of blood products: Perspectives from the ISBT Young Professional Council

BACKGROUND AND OBJECTIVES

Blood services manage the increasingly tight balance between the supply and demand of blood products, and their role in health research is expanding. This review explores the themes that may define the future of blood banking.

MATERIALS AND METHODS

We reviewed the PubMed database for articles on emerging/new blood-derived products and the utilization of blood donors in health research.

RESULTS

In high-income countries (HICs), blood services may consider offering these products: whole blood, cold-stored platelets, synthetic blood components, convalescent plasma, lyophilized plasma and cryopreserved/lyophilized platelets. Many low- and middle-income countries (LMICs) aim to establish a pool of volunteer, non-remunerated blood donors and wean themselves off family replacement donors; and many HICs are relaxing the deferral criteria targeting racial and sexual minorities. Blood services in HICs could achieve plasma self-sufficiency by building plasma-dedicated centres, in collaboration with the private sector. Lastly, blood services should expand their involvement in health research by establishing donor cohorts, conducting serosurveys, studying non-infectious diseases and participating in clinical trials.

CONCLUSION

This article provides a vision of the future for blood services. The introduction of some of these changes will be slower in LMICs, where addressing key operational challenges will likely be prioritized.

Binding mechanism of pentamidine derivatives with human serum acute phase protein α1-acid glycoprotein

Drug binding and interactions with plasma proteins play a crucial role in determining the efficacy of drug delivery, thus significantly impacting the overall pharmacological effect. AGP, the second most abundant plasma protein in blood circulation, has the unique capability to bind drugs and transport various compounds. In our present study, for the first time, we investigated whether AGP, a major component of the acute phase lipocalin in human plasma, can bind with pentamidine derivatives known for their high activity against the fungal pathogen Pneumocystis carinii. This investigation was conducted using integrated spectroscopic techniques and computer-based approaches. According to the results, it was concluded that compounds having heteroatoms (-NCH3) in the aliphatic linker and the addition of a Br atom and a methoxy substituent at the C-2 and C-6 positions on the benzene ring, exhibit strong interactions with the AGP binding site. These compounds are identified as potential candidates for recognition by this protein. MD studies indicated that the tested analogues complexed with AGPs reach an equilibrium state after 60 ns, suggesting the stability of the complexes. This observation was further corroborated by experimental results. Therefore, exploring the interaction mechanism of pentamidine derivatives with plasma proteins holds promise for the development of bis-benzamidine-designed pharmaceutically important drugs.

Therapeutic approaches of cell therapy based on stem cells and terminally differentiated cells: Potential and effectiveness

Cell-based therapy, as a promising regenerative medicine approach, has been a promising and effective strategy to treat or even cure various kinds of diseases and conditions. Generally, two types of cells are used in cell therapy, the first is the stem cell, and the other is a fully differentiated cell. Initially, all cells in the body are derived from stem cells. Based on the capacity, potency and differentiation potential of stem cells, there are four types: totipotent (produces all somatic cells plus perinatal tissues), pluripotent (produces all somatic cells), multipotent (produces many types of cells), and unipotent (produces a particular type of cells). All non-totipotent stem cells can be used for cell therapy, depending on their potency and/or disease state/conditions. Adult fully differentiated cell is another cell type for cell therapy that is isolated from adult tissues or obtained following the differentiation of stem cells. The cells can then be transplanted back into the patient to replace damaged or malfunctioning cells, promote tissue repair, or enhance the targeted organ's overall function. With increasing science and knowledge in biology and medicine, different types of techniques have been developed to obtain efficient cells to use for therapeutic approaches. In this study, the potential and opportunity of use of all cell types, both stem cells and fully differentiated cells, are reviewed.

Berberine mediated fluorescent gold nanoclusters in biomimetic erythrocyte ghosts as a nanocarrier for enhanced photodynamic treatment

Photodynamic therapy (PDT) is a well-established cancer treatment method that employs light to generate reactive oxygen species (ROS) causing oxidative damage to cancer cells. Nevertheless, PDT encounters challenges due to its oxygen-dependent nature, which makes it less effective in hypoxic tumor environments. To address this issue, we have developed a novel nanocomposite known as AuNC@BBR@Ghost. This nanocomposite combines the advantageous features of erythrocyte ghost membranes, the photoresponsive properties of gold nanoclusters (AuNC) and the anticancer characteristics of Berberine (BBR) for cancer treatment. Our synthesized AuNC efficiently produce ROS, with a 25% increase in efficiency when exposed to near-infrared (NIR) irradiation. By harnessing the oxygen-carrying capacity of erythrocyte ghost cells, AuNC@BBR@Ghost demonstrates a significant improvement in ROS generation, achieving an 80% efficiency. Furthermore, the AuNC exhibit tunable emission wavelengths due to their excellent fluorescent properties. In normoxic conditions, treatment of A549 lung carcinoma cells with AuNC@BBR@Ghost followed by exposure to 808 nm NIR irradiation results in a notable increase in intracellular ROS levels, accelerating cell death. In hypoxic conditions, when A549 cells were treated with AuNC@BBR@Ghost, the erythrocyte ghost acted as an oxygen supplement due to the residual hemoglobin, alleviating hypoxia and enhancing the nanocomposite's sensitivity to PDT treatment. Thus, the AuNC@BBR@Ghost nanocomposite achieves an improved effect by combining the advantageous properties of its individual components, resulting in enhanced ROS generation and adaptability to hypoxic conditions. This innovative approach successfully overcomes PDT's limitations, making AuNC@BBR@Ghost a promising nanotheranostic agent with significant potential for advanced cancer therapy.

Drug-loaded erythrocytes: Modern approaches for advanced drug delivery for clinical use

Scientific organizations worldwide are striving to create drug delivery systems that provide a high local concentration of a drug in pathological tissue without side effects on healthy organs in the body. Important physiological properties of red blood cells (RBCs), such as frequent renewal ability, good oxygen carrying ability, unique shape and membrane flexibility, allow them to be used as natural carriers of drugs in the body. Erythrocyte carriers derived from autologous blood are even more promising drug delivery systems due to their immunogenic compatibility, safety, natural uniqueness, simple preparation, biodegradability and convenience of use in clinical practice. This review is focused on the achievements in the clinical application of targeted drug delivery systems based on osmotic methods of loading RBCs, with an emphasis on advancements in their industrial production. This article describes the basic methods used for encapsulating drugs into erythrocytes, key strategic approaches to the clinical use of drug-loaded erythrocytes obtained by hypotonic hemolysis. Moreover, clinical trials of erythrocyte carriers for the targeted delivery are discussed. This article explores the recent advancements and engineering approaches employed in the encapsulation of erythrocytes through hypotonic hemolysis methods, as well as the most promising inventions in this field. There is currently a shortage of reviews focused on the automation of drug loading into RBCs; therefore, our work fills this gap. Finally, further prospects for the development of engineering and technological solutions for the automatic production of drug-loaded RBCs were studied. Automated devices have the potential to provide the widespread production of RBC-encapsulated therapeutic drugs and optimize the process of targeted drug delivery in the body. Furthermore, they can expedite the widespread introduction of this innovative treatment method into clinical practice, thereby significantly expanding the effectiveness of treatment in both surgery and all areas of medicine.

In situ cellular hitchhiking of nanoparticles for drug delivery

Since the inception of the concept of "magic bullet", nanoparticles have evolved to be one of the most effective carriers in drug delivery. Nanoparticles improve the therapeutic efficacy of drugs offering benefits to treating various diseases. Unlike free drugs which freely diffuse and distribute through the body, nanoparticles protect the body from the drug by reducing non-specific interactions while also improving the drug's pharmacokinetics. Despite acquiring some FDA approvals, further clinical application of nanoparticles is majorly hindered by its limited ability to overcome biological barriers resulting in uncontrolled biodistribution and high clearance. The use of cell-inspired systems has emerged as a promising approach to overcome this challenge as cells are biocompatible and have improved access to tissues and organs. One of such is the hitchhiking of nanoparticles to circulating cells such that they are recognized as 'self' components evading clearance and resulting in site-specific drug delivery. In this review, we discuss the concept of nanoparticle cellular hitchhiking, highlighting its advantages, the principles governing the process and the challenges currently limiting its clinical translation. We also discuss in situ hitchhiking as a tool for overcoming these challenges and the considerations to be taken to guide research efforts in advancing this promising technology.

Cellular-Membrane-Derived Vesicles for Cancer Immunotherapy

The medical community is constantly searching for new and innovative ways to treat cancer, and cellular-membrane-derived artificial vesicles are emerging as a promising avenue for cancer immunotherapy. These vesicles, which are derived from mammal and bacteria cell membranes, offer a range of benefits, including compatibility with living organisms, minimal immune response, and prolonged circulation. By modifying their surface, manipulating their genes, combining them with other substances, stimulating them externally, and even enclosing drugs within them, cellular vesicles have the potential to be a powerful tool in fighting cancer. The ability to merge drugs with diverse compositions and functionalities in a localized area is particularly exciting, as it offers a way to combine different immunotherapy treatments for maximum impact. This review contains information on the various sources of these vesicles and discusses some recent developments in cancer immunotherapy using this promising technology. While there are still obstacles to overcome, the possibilities for cellular vesicles in cancer treatment are truly exciting.

Advances in Targeting Drug Biological Carriers for Enhancing Tumor Therapy Efficacy

Chemotherapy drugs continue to be the main component of oncology treatment research and have been proven to be the main treatment modality in tumor therapy. However, the poor delivery efficiency of cancer therapeutic drugs and their potential off-target toxicity significantly limit their effectiveness and extensive application. The recent integration of biological carriers and functional agents is expected to camouflage synthetic biomimetic nanoparticles for targeted delivery. The promising candidates, including but not limited to red blood cells and their membranes, platelets, tumor cell membrane, bacteria, immune cell membrane, and hybrid membrane are typical representatives of biological carriers because of their excellent biocompatibility and biodegradability. Biological carriers are widely used to deliver chemotherapy drugs to improve the effectiveness of drug delivery and therapeutic efficacy in vivo, and tremendous progress is made in this field. This review summarizes recent developments in biological vectors as targeted drug delivery systems based on microenvironmental stimuli-responsive release, thus highlighting the potential applications of target drug biological carriers. The review also discusses the possibility of clinical translation, as well as the exploitation trend of these target drug biological carriers.

Compatibility of Nucleobases Containing Pt(II) Complexes with Red Blood Cells for Possible Drug Delivery Applications

The therapeutic advantages of some platinum complexes as major anticancer chemotherapeutic agents and of nucleoside analogue-based compounds as essential antiviral/antitumor drugs are widely recognized. Red blood cells (RBCs) offer a potential new strategy for the targeted release of therapeutic agents due to their biocompatibility, which can protect loaded drugs from inactivation in the blood, thus improving biodistribution. In this study, we evaluated the feasibility of loading model nucleobase-containing Pt(II) complexes into human RBCs that were highly stabilized by four N-donors and susceptible to further modification for possible antitumor/antiviral applications. Specifically, platinum-based nucleoside derivatives [PtII(dien)(N7-Guo)]2+, [PtII(dien)(N7-dGuo)]2+, and [PtII(dien)(N7-dGTP)] (dien = diethylenetriamine; Guo = guanosine; dGuo = 2'-deoxy-guanosine; dGTP = 5'-(2'-deoxy)-guanosine-triphosphate) were investigated. These Pt(II) complexes were demonstrated to be stable species suitable for incorporation into RBCs. This result opens avenues for the possible incorporation of other metalated nucleobases analogues, with potential antitumor and/or antiviral activity, into RBCs.

Evaluation of Two Osmosis-Based Methods for the Preparation of Drug Delivery Systems Based on Red Blood Cells

Erythrocytes have been thoroughly investigated as drug delivery systems for a wide range of therapeutic molecules and using different kinds of loading methods, outstanding the osmosis-based methods as the most used ones. Most of them involve too much handling of blood components and the immediate obtention of fresh blood. Based on our group's considerable experience in dialysis-based carrier erythrocyte preparation, this study details a simple method based on hypotonic dilution and subsequent resealing that has been developed for stavudine using packed erythrocytes from a local blood bank. Properties of the obtained carrier erythrocytes were studied in comparison to those prepared by dialysis. Erythrocytes' morphology, osmotic fragility, hematological parameters, and in vitro release profiles were evaluated. Loaded erythrocytes obtained with the proposed method did not show impaired properties in comparison with those obtained with our reference method, provided that the buffer composition remained the same. In the present work, we have optimized a simplified method for erythrocytes' drug loading, which can use blood transfusion products and could be easily automatized and scalable.

Carbon Monoxide-Loaded Red Blood Cell Prevents the Onset of Cisplatin-Induced Acute Kidney Injury

Cisplatin-induced acute kidney injury (AKI) is an important factor that limits the clinical use of this drug for the treatment of malignancies. Oxidative stress and inflammation are considered to be the main causes of not only cisplatin-induced death of cancer cells but also cisplatin-induced AKI. Therefore, developing agents that exert antioxidant and anti-inflammatory effects without weakening the anti-tumor effects of cisplatin is highly desirable. Carbon monoxide (CO) has recently attracted interest due to its antioxidant, anti-inflammatory, and anti-tumor properties. Herein, we report that CO-loaded red blood cell (CO-RBC) exerts renoprotective effects on cisplatin-induced AKI. Cisplatin treatment was found to reduce cell viability in proximal tubular cells via oxidative stress and inflammation. Cisplatin-induced cytotoxicity, however, was suppressed by the CO-RBC treatment. The intraperitoneal administration of cisplatin caused an elevation in the blood urea nitrogen and serum creatinine levels. The administration of CO-RBC significantly suppressed these elevations. Furthermore, the administration of CO-RBC also reduced the deterioration of renal histology and tubular cell injury through its antioxidant and anti-inflammatory effects in cisplatin-induced AKI mice. Thus, our data suggest that CO-RBC has the potential to substantially prevent the onset of cisplatin-induced AKI, which, in turn, may improve the usefulness of cisplatin-based chemotherapy.

Maleimide as the PEG end-group promotes macrophage-targeted drug delivery of PEGylated nanoparticles in vivo by enhancing interaction with circulating erythrocytes

Radiotherapy (IR) is capable of enhancing antitumor immune responses. However, IR treatment also aggravates the infiltration of peripheral macrophages into the tumor, resulting in reversing the therapeutic effects of antitumor immunity. Thus, a strategy to effectively prevent tumor infiltration by macrophages may further improved the therapeutic efficacy of radiotherapy. Herein, we found that PEGylated solid lipid nanoparticles with maleimide as PEG end-group (SLN-PEG-Mal) show significantly enhanced adsorption onto RBCs through reacting with reactive sulfhydryl groups on RBCs' surface both in vitro and in vivo, and caused significant changes in the surface properties and morphology of RBCs. These RBCs adsorbed by SLN-PEG-Mal were rapidly removed from circulation due to efficient engulfment by reticuloendothelial macrophages, supporting the usefulness of SLN-PEG-Mal for macrophage-targeted drug delivery. While lacking the use of radioisotope tracing (considered the gold standard for PK/BD studies), our data align with the expected pathway of host defense activation through surface-loaded RBCs. Importantly, injection of paclitaxel-loaded SLN-PEG-Mal effectively inhibited the tumor-infiltration by macrophages, and significantly improved the antitumor immune responses in tumor-bearing mice treated with low-dose irradiation. This study provides insights into the effects of maleimide as PEG end-group on enhancing the interaction between PEGylated nanoparticles and RBCs and offers an effective strategy to inhibit tumor infiltration by circulating macrophages.

Preclinical and clinical developments in enzyme-loaded red blood cells: an update

INTRODUCTION

We have previously described the preclinical developments in enzyme-loaded red blood cells to be used in the treatment of several rare diseases, as well as in chronic conditions.

AREA COVERED

Since our previous publication we have seen further progress in the previously discussed approaches and, interestingly enough, in additional new studies that further strengthen the idea that red blood cell-based therapeutics may have unique advantages over conventional enzyme replacement therapies in terms of efficacy and safety. Here we highlight these investigations and compare, when possible, the reported results versus the current therapeutic approaches.

EXPERT OPINION

The continuous increase in the number of new potential applications and the progress from the encapsulation of a single enzyme to the engineering of an entire metabolic pathway open the field to unexpected developments and confirm the role of red blood cells as cellular bioreactors that can be conveniently manipulated to acquire useful therapeutic metabolic abilities. Positioning of these new approaches versus newly approved drugs is essential for the successful transition of this technology from the preclinical to the clinical stage and hopefully to final approval.

Prediction of Oscillations in Glycolysis in Ethanol-Consuming Erythrocyte-Bioreactors

A mathematical model of energy metabolism in erythrocyte-bioreactors loaded with alcohol dehydrogenase and acetaldehyde dehydrogenase was constructed and analyzed. Such erythrocytes can convert ethanol to acetate using intracellular NAD and can therefore be used to treat alcohol intoxication. Analysis of the model revealed that the rate of ethanol consumption by the erythrocyte-bioreactors increases proportionally to the activity of incorporated ethanol-consuming enzymes until their activity reaches a specific threshold level. When the ethanol-consuming enzyme activity exceeds this threshold, the steady state in the model becomes unstable and the model switches to an oscillation mode caused by the competition between glyceraldehyde phosphate dehydrogenase and ethanol-consuming enzymes for NAD. The amplitude and period of metabolite oscillations first increase with the increase in the activity of the encapsulated enzymes. A further increase in these activities leads to a loss of the glycolysis steady state, and a permanent accumulation of glycolytic intermediates. The oscillation mode and the loss of the steady state can lead to the osmotic destruction of erythrocyte-bioreactors due to an accumulation of intracellular metabolites. Our results demonstrate that the interaction of enzymes encapsulated in erythrocyte-bioreactors with erythrocyte metabolism should be taken into account in order to achieve the optimal efficacy of these bioreactors.

Acrylonitrile adducts: design, synthesis and biological evaluation as antimicrobial, haemolytic and thrombolytic agent

In this work, five acrylonitrile adducts were screened for antibacterial activity against Gram-positive Bacillus subtilis, Microbial Type Culture Collection and Gene Bank (MTCC 1305) and Gram-negative Escherichia coli (MTCC 443). Synthesis was followed by aza-Michael addition reaction, where the acrylonitrile accepts an electron pair from the respective amines and results in the formation of n-alkyliminobis-propionitrile and n-alkyliminopropionitrile under microwave irradiation. Characterization of the compounds were performed using Fourier Transform Infrared (FTIR), Proton Nuclear Magnetic Resonance (¹H NMR) and Electrospray Ionisation Mass Spectrometry (ESI-MS). The particle size characterization was done by Dynamic Light Scattering (DLS) technique. The antibacterial study showed higher inhibition rate for both Gram-positive and Gram-negative bacteria. The antibacterial ability was found to be dose dependent. The minimum inhibitory concentration against both bacteria were found to be 1, 3, 0.4, 1, 3 µl/ml for E. coli and 6, 6, 0.9, 0.5, 5 µl/ml for B. subtilis. Time-kill kinetics evaluation showed that the adducts possess bacteriostatic action. Further it was evaluated for high-throughput in vitro assays to determine the compatibility of the adducts for drug delivery. The haemolytic and thrombolytic activity was analysed against normal mouse erythrocytes. The haemolytic activity showed prominent results, and thereby projecting this acrylonitrile adducts as potent antimicrobial and haemolytic agent.

Dielectric investigation of irradiated RBCs and study the role of Moringa leaves extract against radiation damage

This research article introduces dielectric and thermodynamic state functions as physical markersdetecting both radiation effects and biological repairs to such damages. The red blood cells of rats were physically investigated in this work after whole body irradiation by 7 Gy of gamma rays and trying for reducing the damage effect of ionizing radiation by using the one of the best medicinal plants, Moringa leaves, which are rich with plentiful amounts of antioxidants and nutrients. The animals were divided into six groups; control, Moringa, irradiated, protected, treated, pro-treated. The physical parameters measured were impedance and DC conductivity then, relaxation time, activation energy and enthalpy change were calculated. Most of these parameters showed that the damage occurred in RBCs membrane due to ionizing radiation needs more than four weeks after irradiation to recover. As dipolar relaxation required much more time to occur and charge conduction were greatly reduced.

Possible mechanism of metabolic and drug resistance with L-asparaginase therapy in childhood leukaemia

L-asparaginase, which hydrolyzes asparagine into aspartic acid and ammonia, is frequently used to treat acute lymphoblastic leukaemia in children. When combined with other chemotherapy drugs, the event-free survival rate is 90%. Due to immunogenicity and drug resistance, however, not all patients benefit from it, restricting the use of L-asparaginase therapy in other haematological cancers. To solve the problem of immunogenicity, several L-ASNase variants have emerged, such as Erwinia-ASNase and PEG-ASNase. However, even when Erwinia-ASNase is used as a substitute for E. coli-ASNase or PEG-ASNase, allergic reactions occur in 3%-33% of patients. All of these factors contributed to the development of novel L-ASNases. Additionally, L-ASNase resistance mechanisms, such as the methylation status of ASNS promoters and activation of autophagy, have further emphasized the importance of personalized treatment for paediatric haematological neoplasms. In this review, we discussed the metabolic effects of L-ASNase, mechanisms of drug resistance, applications in non-ALL leukaemia, and the development of novel L-ASNase.

Cell-Based Drug Delivery Systems with Innate Homing Capability as a Novel Nanocarrier Platform

Nanoparticle-based drug delivery systems have been designed to treat various diseases. However, many problems remain, such as inadequate tumor targeting and poor therapeutic outcomes. To overcome these obstacles, cell-based drug delivery systems have been developed. Candidates for cell-mediated drug delivery include blood cells, immune cells, and stem cells with innate tumor tropism and low immunogenicity; they act as a disguise to deliver the therapeutic payload. In drug delivery systems, therapeutic agents are encapsulated intracellularly or attached to the surface of the plasma membrane and transported to the desired site. Here, we review the pros and cons of cell-based therapies and discuss their homing mechanisms in the tumor microenvironment. In addition, different strategies to load therapeutic agents inside or on the surface of circulating cells and the current applications for a wide range of disease treatments are summarized.

Recent Advances in Targeted Nanocarriers for the Management of Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a life-threatening form of breast cancer which has been found to account for 15% of all the subtypes of breast cancer. Currently available treatments are significantly less effective in TNBC management because of several factors such as poor bioavailability, low specificity, multidrug resistance, poor cellular uptake, and unwanted side effects being the major ones. As a rapidly growing field, nano-therapeutics offers promising alternatives for breast cancer treatment. This platform provides a suitable pathway for crossing biological barriers and allowing sustained systemic circulation time and an improved pharmacokinetic profile of the drug. Apart from this, it also provides an optimized target-specific drug delivery system and improves drug accumulation in tumor cells. This review provides insights into the molecular mechanisms associated with the pathogenesis of TNBC, along with summarizing the conventional therapy and recent advances of different nano-carriers for the management of TNBC.

Nanotechnology-based cell-mediated delivery systems for cancer therapy and diagnosis

The global prevalence of cancer is increasing, necessitating new additions to traditional treatments and diagnoses to address shortcomings such as ineffectiveness, complications, and high cost. In this context, nano and microparticulate carriers stand out due to their unique properties such as controlled release, higher bioavailability, and lower toxicity. Despite their popularity, they face several challenges including rapid liver uptake, low chemical stability in blood circulation, immunogenicity concerns, and acute adverse effects. Cell-mediated delivery systems are important topics to research because of their biocompatibility, biodegradability, prolonged delivery, high loading capacity, and targeted drug delivery capabilities. To date, a variety of cells including blood, immune, cancer, and stem cells, sperm, and bacteria have been combined with nanoparticles to develop efficient targeted cancer delivery or diagnosis systems. The review paper aimed to provide an overview of the potential applications of cell-based delivery systems in cancer therapy and diagnosis.

Expansion and differentiation of ex vivo cultured erythroblasts in scalable stirred bioreactors

Transfusion of donor-derived red blood cells (RBCs) is the most common form of cell therapy. Production of transfusion-ready cultured RBCs (cRBCs) is a promising replacement for the current, fully donor-dependent therapy. A single transfusion unit, however, contains 2 × 10¹² RBC, which requires large scale production. Here, we report on the scale-up of cRBC production from static cultures of erythroblasts to 3 L stirred tank bioreactors, and identify the effect of operating conditions on the efficiency of the process. Oxygen requirement of proliferating erythroblasts (0.55-2.01 pg/cell/h) required sparging of air to maintain the dissolved oxygen concentration at the tested setpoint (2.88 mg O₂ /L). Erythroblasts could be cultured at dissolved oxygen concentrations as low as 0.7 O₂ mg/ml without negative impact on proliferation, viability or differentiation dynamics. Stirring speeds of up to 600 rpm supported erythroblast proliferation, while 1800 rpm led to a transient halt in growth and accelerated differentiation followed by a recovery after 5 days of culture. Erythroblasts differentiated in bioreactors, with final enucleation levels and hemoglobin content similar to parallel cultures under static conditions.

Strategies and progresses for enhancing targeted antibiotic delivery

Antibiotic resistance is a global health issue and a potential risk for society. Antibiotics administered through conventional formulations are devoid of targeting effect and often spread to various undesired body sites, leading to sub-lethal concentrations at the site of action and thus resulting in emergence of resistance, as well as side effects. Moreover, we have a very slim antibiotic pipeline. Drug-delivery systems have been designed to control the rate, time, and site of drug release, and innovative approaches for antibiotic delivery provide a glint of hope for addressing these issues. This review elaborates different delivery strategies and approaches employed to overcome the limitations of conventional antibiotic therapy. These include antibiotic conjugates, prodrugs, and nanocarriers for local and targeted antibiotic release. In addition, a wide range of stimuli-responsive nanocarriers and biological carriers for targeted antibiotic delivery are discussed. The potential advantages and limitations of targeted antibiotic delivery strategies are described along with possible solutions to avoid these limitations. A number of antibiotics successfully delivered through these approaches with attained outcomes and potentials are reviewed.

Role of Spectrin in Endocytosis

Cytoskeletal spectrin is found in (non)erythroid cells. Eukaryotic endocytosis takes place for internalizing cargos from extracellular milieu. The role of spectrin in endocytosis still remains poorly understood. Here, I summarize current knowledge of spectrin function, spectrin-based cytoskeleton and endocytosis of erythrocytes, and highlight how spectrin contributes to endocytosis and working models in different types of cells. From an evolutionary viewpoint, I discuss spectrin and endocytosis in a range of organisms, particularly in plants and yeast where spectrin is absent. Together, the role of spectrin in endocytosis is related to its post-translational modification, movement/rearrangement, elimination (by proteases) and meshwork fencing.

Blood cell-based drug delivery systems: a biomimetic platform for antibacterial therapy

With the rapid increase in multidrug-resistance against antibiotics, higher doses of antibiotics or more effective antibiotics are needed to treat diseases, which ultimately leads to a decrease in the body's immunity and seriously threatens human health worldwide. The efficiency of antibiotics has been a large challenge for years. To overcome this problem, many carriers are utilized for anti-bacteria, attempting to optimize the delivery of such drugs and transport them safely and directly to the site of disease. Blood cell-based drug delivery systems present several advantages as compared to polymeric delivery system. These blood cells including red blood cells (RBCs), leukocytes, platelets. The blood cells and their membranes can both be used as drug carriers to deliver antibacterial drugs. In addition, blood cells can overcome many physiological/pathological obstacles faced by nanoparticles in vivo and effectively deliver drugs to the site of the disease. In this paper, we review studies on blood cell-based delivery systems used in antibacterial therapy, and analyze different roles in antibacterial therapy, which provide basis for further study in this field.

Recent advances in overcoming barriers to cell-based delivery systems for cancer immunotherapy

Immunotherapy strategies that use cell-based delivery systems have sparked much interest in the treatment of malignancies, owing to their high biocompatibility, excellent tumor targeting capability, and unique biofunctionalities in the tumor growth process. A variety of design principles for cell-based immunotherapy, including cell surface decoration, cell membrane coating, cell encapsulation, genetically engineered cell, and cell-derived exosomes, give cancer immunotherapy great potential to improve therapeutic efficacy and reduce adverse effects. However, the treatment efficacy of cell-based delivery methods for immunotherapy is still limited, and practical uses are hampered due to complex physiological and immunological obstacles, such as physical barriers to immune infiltration, immunosuppressive tumor microenvironment, upregulation of immunosuppressive pathways, and metabolic restriction. In this review, we present an overview of the design principles of cell-based delivery systems in cancer immunotherapy to maximize the therapeutic impact, along with anatomical, metabolic, and immunological impediments in using cell-based immunotherapy to treat cancer. Following that, a summary of novel delivery strategies that have been created to overcome these obstacles to cell-based immunotherapeutic delivery systems is provided. Also, the obstacles and prospects of next-step development of cell-based delivery systems for cancer immunotherapy are concluded in the end.

Cell-derived membrane biomimetic nanocarriers for targeted therapy of pulmonary disease

Pulmonary diseases are currently one of the major threats of human health, especially considering the recent COVID-19 pandemic. However, the current treatments are facing the challenges like insufficient local drug concentrations, the fast lung clearance and risks to induce unexpected inflammation. Cell-derived membrane biomimetic nanocarriers are recently emerged delivery strategy, showing advantages of long circulation time, excellent biocompatibility and immune escape ability. In this review, applications of using cell-derived membrane biomimetic nanocarriers from diverse cell sources for the targeted therapy of pulmonary disease were summarized. In addition, improvements of the cell-derived membrane biomimetic nanocarriers for augmented therapeutic ability against different kinds of pulmonary diseases were introduced. This review is expected to provide a general guideline for the potential applications of cell-derived membrane biomimetic nanocarriers to treat pulmonary diseases.

Tumor-targeted nano-delivery system of therapeutic RNA

The birth of RNAi technology has pioneered actionability at the molecular level. Compared to DNA, RNA is less stable and therefore requires more demanding delivery vehicles. With their flexible size, shape, structure, and accessible surface modification, non-viral vectors show great promise for application in RNA delivery. Different non-viral vectors have different ways of binding to RNA. Low immunotoxicity gives RNA significant advantages in tumor treatment. However, the delivery of RNA still has many limitations in vivo. This manuscript summarizes the size-targeting dependence of different organs, followed by a summary of nanovesicles currently in or undergoing clinical trials. It also reviews all RNA delivery systems involved in the current study, including natural, bionic, organic, and inorganic systems. It summarizes the advantages and disadvantages of different delivery methods, which will be helpful for future RNA vehicle design. It is hoped that this will be helpful for gene therapy of clinical tumors.

Cyclic arginine-glycine-aspartic acid-modified red blood cells for drug delivery: Synthesis and in vitro evaluation

Red blood cells (RBCs) are an excellent choice for cell preparation research because of their biocompatibility, high drug loading, and long half-life. In this study, doxorubicin (DOX) was encapsulated with RBCs as the carrier. The biotin-avidin system binding principle was used to modify biotinylated cyclic arginine-glycine-aspartic acid (cRGD) onto RBC surfaces for accurate targeting, high drug loading, and sustained drug release. The RBC drug delivery system (DDS) was characterized, and the concentration of surface sulfur in the energy spectrum was 6.330%. The physical and chemical properties of RBC DDS were as follows: drug content, 0.857 mg/mL; particle size, 3339 nm; potential value, -12.5 mV; and cumulative release rate, 81.35%. There was no significant change in RBC morphology for up to seven days. The results of the targeting and cytotoxicity studies of RBC DDS showed that many RBCs covered the surfaces of U251 cells, and the fluorescence intensity was higher than that of MCF-7 cells. The IC50 value of unmodified drug-loaded RBCs was 2.5 times higher than that of targeted modified drug-loaded RBCs, indicating that the targeting of cancer cells produced satisfactory inhibition. This study confirms that the RBC DDS has the characteristics of accurate targeting, high drug loading, and slow drug release, which increases its likelihood of becoming a clinical cancer treatment in the future.

The discovery of berberine erythrocyte-hemoglobin self-assembly delivery system: a neglected carrier underlying its pharmacokinetics

Berberine (BBR) has extremely low concentration and high tissue distribution. However, current pharmacokinetic studies predominantly focus on its concentration in plasma, which could hardly make a comprehensive understanding of its pharmacokinetic process. This study made a pioneering endeavor to explore the erythrocyte-hemoglobin (Hb) self-assembly system of BBR by exploring the interaction of BBR with erythrocyte and the combination of BBR with Hb. Results showed that BBR had a low bioavailability (C₀ = 2.833 μg/mL via intravenous administration of 2.5 mg/kg BBR and C_max = 0.260 μg/mL via oral administration of 400 mg/kg BBR). Besides, BBR achieved higher concentrations in erythrocytes than plasma, and the erythrocytes count and Hb content were significantly decreased after intravenous administration. Hemolysis rate indicated the BBR-erythrocyte system (with 2% erythrocytes) was relatively stable without hemolysis at the concentration of 1.00 mg/mL. And the maximum percentage of drug loading was 100% when the BBR-erythrocyte concentration was 0.185 μg/mL. Furthermore, incubation of BBR and erythrocytes resulted in internalization of the erythrocyte membrane and the formation of intracellular vacuoles. The thermodynamic parameters indicated that the binding process of bovine hemoglobin (BHB) and BBR was spontaneous. UV-vis absorption spectra, synchronous fluorescence, circular dichroism and Raman spectra collectively indicated that BBR showed strong binding affinity toward BHB and affected the molecular environment of residues like tryptophan and tyrosine in BHB, resulting in the conformational changes of its secondary and tertiary structure. Molecular docking indicated BBR interacted with Arg-141 residue of BHB via hydrogen bond with the bond length of 2.55 Å. The ΔG value of the BHB-BBR system was −31.79 kJ/mol. Molecular dynamics simulation indicated the root mean square derivation of BBR-BHB was <0.025 nm, suggestive of stable conformation. Cumulatively, there was an erythrocyte-Hb self-assembled drug delivery system after oral or intravenous administration of BBR, which conceivably gained novel insight into the discrepancy between the extremely low plasma concentration and relatively high tissue concentration of BBR.

Liposomes as Tools to Improve Therapeutic Enzyme Performance

The drugs concept has changed during the last few decades, meaning the acceptance of not only low molecular weight entities but also macromolecules as bioagent constituents of pharmaceutics. This has opened a new era for a different class of molecules, namely proteins in general and enzymes in particular. The use of enzymes as therapeutics has posed new challenges in terms of delivery and the need for appropriate carrier systems. In this review, we will focus on enzymes with therapeutic properties and their applications, listing some that reached the pharmaceutical market. Problems associated with their clinical use and nanotechnological strategies to solve some of their drawbacks (i.e., immunogenic reactions and low circulation time) will be addressed. Drug delivery systems will be discussed, with special attention being paid to liposomes, the most well-studied and suitable nanosystem for enzyme delivery in vivo. Examples of liposomal enzymatic formulations under development will be described and successful pre-clinical results of two enzymes, L-Asparaginase and Superoxide dismutase, following their association with liposomes will be extensively discussed.

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.

Novel Insights on the Use of L-Asparaginase as an Efficient and Safe Anti-Cancer Therapy

Simple Summary

L-asparaginase (L-ASNase) therapy is key for achieving the very high cure rate of pediatric acute lymphoblastic leukemia (ALL), yet its use is mostly confined to this indication. One main reason preventing the expansion of today’s FDA-approved L-ASNases to solid cancers is their high toxicity and side effects, which become especially challenging in adult patients. The design of optimized L-ASNase molecules provides opportunities to overcome these unwanted toxicities. An additional challenge to broader application of L-ASNases is how cells can counter the pharmacological effect of this drug and the identification of L-ASNases resistance mechanisms. In this review, we discuss recent insights into L-ASNase adverse effects, resistance mechanisms, and how novel L-ASNase variants and drug combinations can expand its clinical applicability, with a focus on both hematological and solid tumors.

Abstract

L-Asparaginase (L-ASNase) is an enzyme that hydrolyses the amino acid asparagine into aspartic acid and ammonia. Systemic administration of bacterial L-ASNase is successfully used to lower the bioavailability of this non-essential amino acid and to eradicate rapidly proliferating cancer cells with a high demand for exogenous asparagine. Currently, it is a cornerstone drug in the treatment of the most common pediatric cancer, acute lymphoblastic leukemia (ALL). Since these lymphoblasts lack the expression of asparagine synthetase (ASNS), these cells depend on the uptake of extracellular asparagine for survival. Interestingly, recent reports have illustrated that L-ASNase may also have clinical potential for the treatment of other aggressive subtypes of hematological or solid cancers. However, immunogenic and other severe adverse side effects limit optimal clinical use and often lead to treatment discontinuation. The design of optimized and novel L-ASNase formulations provides opportunities to overcome these limitations. In addition, identification of multiple L-ASNase resistance mechanisms, including ASNS promoter reactivation and desensitization, has fueled research into promising novel drug combinations to overcome chemoresistance. In this review, we discuss recent insights into L-ASNase adverse effects, resistance both in hematological and solid tumors, and how novel L-ASNase variants and drug combinations can expand its clinical applicability.

Light-Triggered Drug Release from Red Blood Cells Suppresses Arthritic Inflammation

Arthritis is a leading cause of disability in adults, which can be intensely incapacitating. The location and intensity of the pain is both subjective and challenging to manage. Consequently, patient-directed delivery of anti-inflammatories is an essential component of future therapeutic strategies for the management of this disorder. We describe the design and application of a light responsive red blood cell (RBC) conveyed dexamethasone (Dex) construct that enables targeted drug delivery upon illumination of the inflamed site. The red wavelength (650 nm) responsive nature of the phototherapeutic was validated using tissue phantoms mimicking the light absorbing properties of various skin types. Furthermore, photoreleased Dex has the same impact on cellular responses as conventional Dex. Murine RBCs containing the photoactivatable therapeutic display comparable circulation properties as fluorescently labelled RBCs. In addition, a single dose of light-targeted Dex delivery is 5-fold more effective in suppressing inflammation than the parent drug, delivered serially over multiple days. These results are consistent with the notion that the circulatory system be used as an on-command drug depot, providing the means to therapeutically target diseased sites both efficiently and effectively.