When Albumin Meets Liposomes: A Feasible Drug Carrier for Biomedical Applications

Impact of Lipid Composition on Vesicle Protein Adsorption: A BSA Case Study

Investigating the interaction between liposomes and proteins is of paramount importance in the development of liposomal formulations with real potential for bench-to-bedside transfer. Upon entering the body, proteins are immediately adsorbed on the liposomal surface, changing the nanovehicles' biological identity, which has a significant impact on their biodistribution and pharmacokinetics and ultimately on their therapeutic effect. Albumin is the most abundant plasma protein and thus usually adsorbs immediately on the liposomal surface. We herein report a comprehensive investigation on the adsorption of model protein bovine serum albumin (BSA) onto liposomal vesicles containing the zwitterionic lipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), in combination with either cholesterol (CHOL) or the cationic lipid 1,2-dioleoyl-3-trimethylammoniumpropane (DOTAP). While many studies regarding protein adsorption on the surface of liposomes with different compositions have been performed, to the best of our knowledge, the differential responses of CHOL and DOTAP upon albumin adsorption on vesicles have not yet been investigated. UV-vis spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed a strong influence of the phospholipid membrane composition on protein adsorption. Hence, it was found that DOTAP-containing vesicles adsorb proteins more robustly but also aggregate in the presence of BSA, as confirmed by DLS and TEM. Separation of liposome-protein complexes from unadsorbed proteins performed by means of centrifugation and size exclusion chromatography (SEC) was also investigated. Our results show that neither method can be regarded as a golden experimental setup to study the protein corona of liposomes. Yet, SEC proved to be more successful in the separation of unbound proteins, although the amount of lipid loss upon liposome elution was higher than expected. In addition, coarse-grained molecular dynamics simulations were employed to ascertain key membrane parameters, such as the membrane thickness and area per lipid. Overall, this study highlights the importance of surface charge and membrane fluidity in influencing the extent of protein adsorption. We hope that our investigation will be a valuable contribution to better understanding protein-vesicle interactions for improved nanocarrier design.

Targeting triple negative breast cancer stem cells using nanocarriers

Breast cancer is a complex and heterogeneous disease, encompassing various subtypes characterized by distinct molecular features, clinical behaviors, and treatment responses. Categorization of subtypes is based on the presence or absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), leading to subtypes such as luminal A, luminal B, HER2-positive, and triple-negative breast cancer (TNBC). TNBC, comprising around 20% of all breast cancers, lacks expression of ER, PR, and HER2 receptors, rendering it unresponsive to targeted therapies and presenting significant challenges in treatment. TNBC is associated with aggressive behavior, high rates of recurrence, and resistance to chemotherapy. Tumor initiation, progression, and treatment resistance in TNBC are attributed to breast cancer stem cells (BCSCs), which possess self-renewal, differentiation, and tumorigenic potential. Surface markers, self-renewal pathways (Notch, Wnt, Hedgehog signaling), apoptotic protein (Bcl-2), angiogenesis inhibition (VEGF inhibitors), and immune modulation (cytokines, immune checkpoint inhibitors) are among the key targets discussed in this review. However, targeting the BCSC subpopulation in TNBC presents challenges, including off-target effects, low solubility, and bioavailability of anti-BCSC agents. Nanoparticle-based therapies offer a promising approach to target various molecular pathways and cellular processes implicated in survival of BSCS in TNBC. In this review, we explore various nanocarrier-based approaches for targeting BCSCs in TNBC, aiming to overcome these challenges and improve treatment outcomes for TNBC patients. These nanoparticle-based therapeutic strategies hold promise for addressing the therapeutic gap in TNBC treatment by delivering targeted therapies to BCSCs while minimizing systemic toxicity and enhancing treatment efficacy.

An Overview of Advances in Rare Cancer Diagnosis and Treatment

Cancer stands as the leading global cause of mortality, with rare cancer comprising 230 distinct subtypes characterized by infrequent incidence. Despite the inherent challenges in addressing the diagnosis and treatment of rare cancers due to their low occurrence rates, several biomedical breakthroughs have led to significant advancement in both areas. This review provides a comprehensive overview of state-of-the-art diagnostic techniques that encompass new-generation sequencing and multi-omics, coupled with the integration of artificial intelligence and machine learning, that have revolutionized rare cancer diagnosis. In addition, this review highlights the latest innovations in rare cancer therapeutic options, comprising immunotherapy, targeted therapy, transplantation, and drug combination therapy, that have undergone clinical trials and significantly contribute to the tumor remission and overall survival of rare cancer patients. In this review, we summarize recent breakthroughs and insights in the understanding of rare cancer pathophysiology, diagnosis, and therapeutic modalities, as well as the challenges faced in the development of rare cancer diagnosis data interpretation and drug development.

Polymer Conjugate as the New Promising Drug Delivery System for Combination Therapy against Cancer

This review highlights the advantages of combination therapy using polymer conjugates as drug delivery systems for cancer treatment. In this review, the specific structures and materials of polymer conjugates, as well as the different types of combination chemotherapy strategies, are discussed. Specific targeting strategies, such as monoclonal antibody therapy and small molecule ligands, are also explored. Additionally, self-assembled polymer micelles and overcoming multidrug resistance are described as potential strategies for combination therapy. The assessment of combinational therapeutic efficacy and the challenges associated with polymer conjugates are also addressed. The future outlook aims to overcome these challenges and improve the effectiveness of drug delivery systems for combination therapy. The conclusion emphasizes the potential of polymer conjugates in combination therapy while acknowledging the need for further research and development in this field.

Applications of human and bovine serum albumins in biomedical engineering: A review

Serum albumin, commonly recognized as a predominant major plasma protein, is ubiquitously distributed among vertebrates, demonstrating versatility and widespread accessibility. Numerous studies have discussed the composition and attributes of human and bovine serum albumin; nonetheless, few systematic and comprehensive summaries on human and bovine serum albumin exist. This paper reviews the applications of human and bovine serum albumin in biomedical engineering. First, we introduce the differences in the structure of human and bovine serum albumin. Next, we describe the extraction methods for human and bovine serum albumin (fractionation process separation, magnetic adsorption, reverse micellar (RM) extraction, and genetic engineering) and the advantages and disadvantages of recently developed extraction methods. The characteristics of different processing forms of human and bovine serum albumin are also discussed, concomitantly elucidating their intrinsic properties, functions, and applications in biomedicine. Notably, their pivotal functions as carriers for drugs and tissue-engineered scaffolds, as well as their contributions to cell reproduction and bioimaging, are critically examined. Finally, to provide guidance for researchers in their future work, this review summarizes the current state of human and bovine serum albumin research and outlines potential future research topics.

Organic and Biogenic Nanocarriers as Bio-Friendly Systems for Bioactive Compounds' Delivery: State-of-the Art and Challenges

"Green" strategies to build up novel organic nanocarriers with bioperformance are modern trends in nanotechnology. In this way, the valorization of bio-wastes and the use of living systems to develop multifunctional organic and biogenic nanocarriers (OBNs) have revolutionized the nanotechnological and biomedical fields. This paper is a comprehensive review related to OBNs for bioactives' delivery, providing an overview of the reports on the past two decades. In the first part, several classes of bioactive compounds and their therapeutic role are briefly presented. A broad section is dedicated to the main categories of organic and biogenic nanocarriers. The major challenges regarding the eco-design and the fate of OBNs are suggested to overcome some toxicity-related drawbacks. Future directions and opportunities, and finding "green" solutions for solving the problems related to nanocarriers, are outlined in the final of this paper. We believe that through this review, we will capture the attention of the readers and will open new perspectives for new solutions/ideas for the discovery of more efficient and "green" ways in developing novel bioperformant nanocarriers for transporting bioactive agents.

Combination of micelles and liposomes as a promising drug delivery system: a review

Among various nanocarriers, liposomes, and micelles are relatively mature drug delivery systems with the advantages of prolonging drug half-life, reducing toxicity, and improving efficacy. However, both have problems, such as poor stability and insufficient targeting. To further exploit the excellent properties of micelles and liposomes and avoid their shortcomings, researchers have developed new drug delivery systems by combining the two and making use of their respective advantages to achieve the goals of increasing the drug loading capacity, multiple targeting, and multiple drug delivery. The results have demonstrated that this new combination approach is a very promising delivery platform. In this paper, we review the combination strategies, preparation methods, and applications of micelles and liposomes to introduce the research progress, advantages, and challenges of composite carriers.

Mesenchymal stem cell secretome and extracellular vesicles for neurodegenerative diseases: Risk-benefit profile and next steps for the market access

Neurodegenerative diseases represent a growing burden on healthcare systems worldwide. Mesenchymal stem cells (MSCs) have shown promise as a potential therapy due to their neuroregenerative, neuroprotective, and immunomodulatory properties, which are, however, linked to the bioactive substances they release, collectively known as secretome. This paper provides an overview of the most recent research on the safety and efficacy of MSC-derived secretome and extracellular vesicles (EVs) in clinical (if available) and preclinical models of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, Huntington's disease, acute ischemic stroke, and spinal cord injury. The article explores the biologically active substances within MSC-secretome/EVs, the mechanisms responsible for the observed therapeutic effects, and the strategies that may be used to optimize MSC-secretome/EVs production based on specific therapeutic needs. The review concludes with a critical discussion of current clinical trials and a perspective on potential future directions in translating MSC-secretome and EVs into the clinic, specifically regarding how to address the challenges associated with their pharmaceutical manufacturing, including scalability, batch-to-batch consistency, adherence to Good Manufacturing Practices (GMP) guidelines, formulation, and storage, along with quality controls, access to the market and relative costs, value for money and impact on total expenditure.

In Vitro and In Vivo Synergistic Antitumor Activity of Albumin-Coated Oleic Acid-Loaded Liposomes toward Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal and prevalent cancers, closely associated with cirrhosis and fibrosis. This study aimed to assess the antitumor activity of oleic acid-liposomes (uncoated liposomes) upon coating with albumin against HCC. The in vitro studies revealed the high safety of the prepared uncoated and albumin-coated liposomes to normal HFB-4 cells (EC100 of 35.57 ± 0.17 and 79.133 ± 2.92 µM, respectively) with significant anticancer activity against HepG-2 cells with IC50 of 56.29 ± 0.91 and 26.74 ± 0.64 µM, respectively. The albumin-coated liposomes revealed superior apoptosis induction potential (80.7%) with significant upregulation of p53 gene expression (> 7.0-fold), compared to OA. The in vivo study revealed that the administration of uncoated or albumin-coated liposomes (100 mg/kg) for six weeks markedly retarded the DENA-induced HCC in Wistar albino rates through regulating the liver enzymes, total bilirubin level, pro-inflammatory cytokines, and oxidative stress. Accordingly, the current study supports the in vitro and in vivo chemo-preventive feature of albumin-coated liposomes against HCC through modulation of apoptosis, improvement of the immune response, reduction of inflammation, and restoration of impaired oxidative stress, which is the first reported to the best of our knowledge.

Protein Corona Attenuates the Targeting of Antitumor Sialyl Lewis X-Decorated Liposomes to Vascular Endothelial Cells under Flow Conditions

Previously, we showed in the human umbilical vein endothelial cells (HUVECs) model that a liposome formulation of melphalan lipophilic prodrug (MlphDG) decorated with selectin ligand tetrasaccharide Sialyl Lewis X (SiaLe^X) undergoes specific uptake by activated cells and in an in vivo tumor model causes a severe antivascular effect. Here, we cultured HUVECs in a microfluidic chip and then applied the liposome formulations to study their interactions with the cells in situ under hydrodynamic conditions close to capillary blood flow using confocal fluorescent microscopy. The incorporation of 5 to 10% SiaLe^X conjugate in the bilayer of MlphDG liposomes increased their consumption exclusively by activated endotheliocytes. The increase of serum concentration from 20 to 100% in the flow resulted in lower liposome uptake by the cells. To elucidate the possible roles of plasma proteins in the liposome-cell interactions, liposome protein coronas were isolated and analyzed by shotgun proteomics and immunoblotting of selected proteins. Proteomic analysis showed that a gradual increase in SiaLe^X content correlated with the overall enrichment of the liposome-associated proteins with several apolipoproteins, including the most positively charged one, ApoC1, and serum amyloid A4, associated with inflammation, on the one hand, and a decrease in the content of bound immunoglobulins, on the other. The article discusses the potential interference of the proteins in the binding of liposomes to selectins of endothelial cells.

Coating Materials to Increase the Stability of Liposomes

Liposomes carry various compounds with applications in pharmaceutical, food, and cosmetic fields, and the administration route is especially parenteral, oral, or transdermal. Liposomes are used to preserve and release the internal components, thus maintaining the properties of the compounds, the stability and shelf life of the encapsulated products, and their functional benefits. The main problem in obtaining liposomes at the industrial level is their low stability due to fragile phospholipid membranes. To increase the stability of liposomes, phospholipid bilayers have been modified or different coating materials have been developed and studied, both for liposomes with applications in the pharmaceutical field and liposomes in the food field. In the cosmetic field, liposomes need no additional coating because the liposomal formulation is intended to have a fast penetration into the skin. The aim of this review is to provide current knowledge regarding physical and chemical factors that influence stability, coating materials for liposomes with applications in the pharmaceutical and food fields to increase the stability of liposomes containing various sensitive compounds, and absorption of the liposomes and commercial liposomal products obtained through various technologies available on the market.

Laser Ablated Albumin Functionalized Spherical Gold Nanoparticles Indicated for Stem Cell Tracking

Cell tracking in cell-based therapy applications helps distinguish cell participation among paracrine effect, neovascularization, and matrix deposition. This preliminary study examined the cellular uptake of gold nanoparticles (AuNPs), observing cytotoxicity and uptake of different sizes and AuNPs concentrations in Adipose-derived stromal cells (ASCs). ASCs were incubated for 24 h with Laser ablated Albumin functionalized spherical AuNPs (LA-AuNPs), with average sizes of 2 nm and 53 nm in diameter, in four concentrations, 127 µM, 84 µM, 42 µM, and 23 µM. Cytotoxicity was examined by Live/Dead assay, and erythrocyte hemolysis, and the effect on the cytoskeleton was investigated by immunocytochemistry for β-actin. The LA-AuNPs were internalized by the ASCs in a size and concentration-dependent manner. Clusters were observed as dispersed small ones in the cytosol, and as a sizeable perinuclear cluster, without significant harmful effects on the cells for up to 2 weeks. The Live/Dead and hemolysis percentage results complemented the observations that the larger 53 nm LA-AuNPs in the highest concentrated solution significantly lowered cell viability. The demonstrated safety, cellular uptake, and labelling persistency with LA-AuNPs, synthesized without the combination of chemical solutions, support their use for cell tracking in tissue engineering applications.

Towards understanding the binding affinity of lipid drug carriers to serum albumin

In the past several years there has been a rapid rise in the use of lipid-based drug formulations. In the case of intravenous drug administration the interaction of lipid carrier with serum albumin is crucial for the distribution of the bioactive molecules in the bloodstream and reaching the target tissue. In this work, we have explored the interaction of serum albumin with three-component lipid monolayer build of palmitoyloleoylphosphatidylcholine (POPC), sphingomyelin (SM), and cholesterol (Chol). Using wide range of lipid compositions and various concentrations of serum albumin we identified the factors governing the lipid-protein binding. Our study revealed that albumin can penetrate selectively the monolayers of POPC/SM/Chol depending on the lipid composition in the mixture. Moreover, the interaction of albumin with monolayer can be controlled by the molecular density of the film and the concentration of protein. The adsorbed albumin exists in the film on the top of lipid monolayer. This behavior may lead to the increase of the size and charge of the lipid carrier and affect the drug transport throughout the bloodstream. The results of this work provide essential physicochemical data that can be used for predicting the pharmacokinetic profile of lipid-based formulations.

Films, Gels and Electrospun Fibers from Serum Albumin Globular Protein for Medical Device Coating, Biomolecule Delivery and Regenerative Engineering

Albumin is a natural biomaterial that is abundantly available in blood and body fluids. It is clinically used as a plasma expander, thereby increasing the plasma thiol concentration due to its cysteine residues. Albumin is a regulator of intervascular oncotic pressure, serves as an anti-inflammatory modulator, and it has a buffering role due to its histidine imidazole residues. Because of its unique biological and physical properties, albumin has also emerged as a suitable biomaterial for coating implantable devices, for cell and drug delivery, and as a scaffold for tissue engineering and regenerative medicine. As a biomaterial, albumin can be used as surface-modifying film or processed either as cross-linked protein gels or as electrospun fibers. Herein we have discussed how albumin protein can be utilized in regenerative medicine as a hydrogel and as a fibrous mat for a diverse role in successfully delivering drugs, genes, and cells to targeted tissues and organs. The review of prior studies indicated that albumin is a tunable biomaterial from which different types of scaffolds with mechanical properties adjustable for various biomedical applications can be fabricated. Based on the progress made to date, we concluded that albumin-based device coatings, delivery of drugs, genes, and cells are promising strategies in regenerative and personalized medicine.

Spectroscopy Study of Albumin Interaction with Negatively Charged Liposome Membranes: Mutual Structural Effects of the Protein and the Bilayers

Liposomes as drug carriers are usually injected into the systemic circulation where they are instantly exposed to plasma proteins. Liposome-protein interactions can affect both the stability of liposomes and the conformation of the associated protein leading to the altered biodistribution of the carrier. In this work, mutual effects of albumin and liposomal membrane in the course of the protein's adsorption were examined in terms of quantity of bound protein, its structure, liposome membrane permeability, and changes in physicochemical characteristics of the liposomes. Fluorescence spectroscopy methods and Fourier transform infrared spectroscopy (ATR-FTIR), which provides information about specific groups in lipids involved in interaction with the protein, were used to monitor adsorption of albumin with liposomes based on egg phosphatidylcholine with various additives of negatively charged lipidic components, such as phosphatidylinositol, ganglioside GM₁, or the acidic lipopeptide. Less than a dozen of the protein molecules were tightly bound to a liposome independently of bilayer composition, yet they had a detectable impact on the bilayer. Albumin conformational changes during adsorption were partially related to bilayer microhydrophobicity. Ganglioside GM₁ showed preferable features for evading undesirable structural changes.

Enhancement of the Antifungal Activity of Chitinase by Palmitoylation and the Synergy of Palmitoylated Chitinase with Amphotericin B

Combinations of antifungal drugs can have synergistic antifungal activity, achieving high therapeutic efficacy while minimizing the side effects. Amphotericin B (AMB) has been used as a standard antifungal drug for fungal infections; however, because of its high toxicity, new strategies to minimize the required dose are desirable. Chitinases have recently received attention as alternative safe antifungal agents. Herein, we report the combination of palmitoylated chitinase domains with AMB to enhance the antifungal activity. The chitin-binding domain (LysM) from Pteris ryukyuensis chitinase was site-specifically palmitoylated by conjugation reaction catalyzed by microbial transglutaminase. The palmitoylated LysM (LysM-Pal) exhibited strong antifungal activity against Trichoderma viride, inhibiting the growth completely at a concentration of 2 μM. This antifungal effect of LysM-Pal was mainly due to the effect of anchoring of palmitic acid motif to the plasma membrane of fungi. A combination of AMB with LysM-Pal resulted in synergistic enhancement of the antifungal activity. Intriguingly, LysM-Pal exhibited higher level of antifungal activity enhancement than palmitoylated catalytic domain (CatD) and fusion of LysM and CatD. Addition of 0.5 μM LysM-Pal to AMB reduced the minimal inhibition concentration of AMB to 0.31 μM (2.5 μM without LysM-Pal). The possible mechanism of the synergistic effect of AMB and LysM-Pal is destabilization of the plasma membrane by anchoring of palmitic acid and ergosterol extraction by AMB and destabilization of the chitin layer by LysM binding. The combination of LysM-Pal with AMB can drastically reduce the dose of AMB and may be a useful strategy to treat fungal infections.

Synthesis and Evaluation of the Insulin-Albumin Conjugate with Prolonged Glycemic Control

Engineering therapeutic proteins to improve their half-life so as to sustain physiologically relevant extended activity is the need of the hour in biopharmaceutical research. In this study, insulin and bovine serum albumin (BSA) were independently functionalized rationally and were later conjugated to prolong the half-life of insulin. The thiol functionalization of BSA with 2-imminothiolane in the ratio 1:20 yielded an average of 6-8 thiols/BSA, which then reacted with maleimide-functionalized insulin to form an insulin-albumin conjugate. The bioconjugate was purified by size exclusion chromatography, and the increase in size was confirmed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis. Bioconjugation resulted in a multi-fold increase in the hydrodynamic volume of the insulin-albumin conjugate as measured in DLS when compared to BSA. The glucose uptake assay with 3LT3-L1 cell lines was performed, and the mean fluorescence intensity (MFI) of 16.16 observed for the insulin-albumin conjugate was comparable to insulin (19.42). The blood glucose reducing capacity of the insulin-albumin conjugate in streptozotocin induced diabetic male Wistar rats was well maintained up to 72 h when compared to native insulin. Further, a three-fold increase in plasma insulin concentration was observed in bioconjugate treated animals as against insulin treated animals after 24 h of treatment using ELISA. The histological analysis of different organs of the bioconjugate treated rats indicated that it was non-toxic. This study has paved a way for further detailed studies on similar bioconjugates to develop next-generation biotherapeutics for treating diabetes.

Easy preparation of a liposome-mediated protein delivery system by freeze-thawing a liposome–protein complex

Homeostasis can be achieved by adding a protein supplement; however, an appropriate vector is required to deliver the protein into the cell because of the low stability of proteins in...

Toxicology of Nanoparticles in Drug Delivery

Nanoparticles have revolutionized biomedicine especially in the field of drug delivery due to their intriguing properties such as systemic stability, level of solubility, and target site specificity. It can, however, be both beneficial and damaging depending on the properties in different environments, thus highlighting the importance of nanotoxicology studies before use in humans. Different types of nanoparticles have been used in drug delivery, and this review summarizes the recent toxicity studies of these nanoparticles. The toxicological evaluation of three widely used nanoparticles in drug delivery that are metal, lipid, and protein nanoparticles has been discussed in detail. Studies have recorded several toxic effects of various nanoparticles such as metal-based nanoparticles have been linked to increased oxidative stress and have the potential to infiltrate the cell nucleus and protein-based nanoparticles have been observed to have hepatotoxicity and nephrotoxicity as their adverse effects. Considering the increasing application of nanoparticles in drug delivery and the growing concerns of regulatory authorities regarding the toxicity of nanocarriers in living organisms, it requires urgent attention to identify the gap in toxicity studies. The review highlights the gap in toxicity studies and potential focus areas to overcome the existing challenges.

Systematic interaction of plasma albumin with the efficacy of chemotherapeutic drugs

Albumin, as the most abundant plasma protein, plays an integral role in the transport of a variety of exogenous and endogenous ligands in the bloodstream and extravascular spaces. For exogenous drugs, especially chemotherapeutic drugs, binding to and being delivered by albumin can significantly affect their efficacy. Meanwhile, albumin can also bind to many endogenous ligands, such as fatty acids, with important physiological significance that can affect tumor proliferation and metabolism. In this review, we summarize how albumin with unique properties affects chemotherapeutic drugs efficacy from the aspects of drug outcome in blood, toxicity, tumor accumulation and direct or indirect interactions with fatty acids, plus application of albumin-based carriers for anti-tumor drug delivery.