Liposomes Modified with Superhydrophilic Polymer Linked to a Nonphospholipid Anchor Exhibit Reduced Complement Activation and Enhanced Circulation

Ferritin versus Liposomes: A Comparative Analysis of Protein- and Lipid-Based Drug Delivery Systems

Drug delivery systems (DDSs) are crucial for the controlled release and targeted delivery of therapeutic agents, enhancing the stability and specificity of small molecules, nucleic acids, or peptides and addressing challenges such as drug instability and poor tissue targeting, particularly in oncology. Over the past few decades, liposomes have become one of the most widely used DDSs due to their unique physicochemical properties and biocompatibility. In the 1990s, liposomes were approved by the FDA as the first nanomedicine for disease treatment. Ferritin, a natural protein with a hollow nanocage structure, shares many similarities in architecture and functionality with liposomes. As an innovative DDS, ferritin offers distinct advantages including inherent tumor-targeting capabilities and exceptional biocompatibility. Liposomes and ferritin represent, respectively, established and emerging approaches in drug delivery, both excelling in key features like encapsulation efficiency and biocompatibility, which align with the standards for pharmaceutical carriers. While liposomal formulations have been clinically used, challenges such as precision targeting remain unresolved. In contrast, although ferritins hold considerable promise for drug delivery, they have not yet been implemented in clinical practice. In this review, we provide a comprehensive analysis of ferritins and liposomes as drug delivery vehicles, evaluating their drug-loading capacities, tumor-targeting capabilities, biocompatibility, and therapeutic potential. On the basis of a comparison of their intended applications and inherent limitations in the context of current treatment strategies, ferritin is expected to be an ideal delivery vehicle for tumor-targeted therapy and a strong candidate for clinical translation in the near future.

Artemisinin emulgel ameliorates cartilage degradation in knee osteoarthritis: in vitro and in vivo studies

Aim: Laboratory scale-up of artemisinin-loaded emulgel (ART-emulgel) was carried out and characterized for therapeutic performance in osteoarthritis (OA).Materials & methods: The solubility of ART in various oils, surfactants and co-surfactants were screened for construction of pseudo ternary phase diagram (TPD), followed by scale-up of artemisinin loaded nanoemulsion (ART-NE). ART-NE was amalgamated with Carbopol Ultrez 10-NF to prepare ART-emulgel that was later characterized in vitro and in vivo to analyze therapeutic efficacy in monosodium-iodoacetate (MIA) induced knee OA.Results: The droplet diameter of ART-NE was estimated to be 104.3 ± 2.593 nm with a polydispersity index of 0.245 ± 0.019 in addition to ζ-potential of 0.434 ± 0.028 mV. Steady-state flux and permeability coefficient for ART-emulgel were estimated to be 0.651 ± 0.031 µg.cm2/h and 0.245 ± 0.011 cm/h, respectively. ART-emulgel demonstrated 43.18% reduction in COX-2 level; 52.28% drop in IL-1β, and 88.78% alleviation of Tumor Necrosis Factor-α (TNF-α) level when compared with monosodium-iodoacetate induced OA rats. ART-emulgel and injectable ART (intra-articular; I.A) portrayed minor synovial erosion compared with blank and diclofenac emulgel. Histopathological evidences indicated restoration of cartilage integrity followed by reduction of OARSI scores in ART-emulgel when compared with disease control animals.Conclusion: ART-emulgel is a potential dosage form for translating into a clinically viable product for the management of OA.

Long circulating liposomal platform utilizing hydrophilic polymer-based surface modification: preparation, characterisation, and biological evaluation

Liposomes are one of the most important drug delivery vectors, nowadays used in clinics. In general, polyethylene glycol (PEG) is used to ensure the stealth properties of the liposomes. Here, we have employed hydrophilic, biocompatible and highly non-fouling N-(2-hydroxypropyl) methacrylamide (HPMA)-based copolymers containing hydrophobic cholesterol anchors for the surface modification of liposomes, which were prepared by the method of lipid film hydration and extrusion through 100 nm polycarbonate filters. Efficient surface modification of liposomes was confirmed by transmission electron microscopy, atomic force microscopy, and gradient ultracentrifugation. The ability of long-term circulation in the vascular bed was demonstrated in rabbits after i.v. application of fluorescently labelled liposomes. Compared to PEGylated liposomes, HPMA-based copolymer-modified liposomes did not induce specific antibody formation and did not activate murine and human complement. Compared with PEGylated liposomes, HPMA-based copolymer-modified liposomes showed a better long-circulating effect after repeated administration. HPMA-based copolymer-modified liposomes thus represent suitable new candidates for a generation of safer and improved liposomal drug delivery platforms.

Multifunctional lipid-based nanoparticles for wound healing and antibacterial applications: A review

Wound healing primarily involves preventing severe infections, accelerating healing, and reducing pain and scarring. Therefore, the multifunctional application of lipid-based nanoparticles (LBNs) has received considerable attention in drug discovery due to their solid or liquid lipid core, which increases their ability to provide prolonged drug release, reduce treatment costs, and improve patient compliance. LBNs have also been used in medical and cosmetic practices and formulated for various products based on skin type, disease conditions, administration product costs, efficiency, stability, and toxicity; therefore, understanding their interaction with biological systems is very important. Therefore, it is necessary to perform an in-depth analysis of the results from a comprehensive characterization process to produce lipid-based drug delivery systems with desired properties. This review will provide detailed information on the different types of LBNs, their formulation methods, characterisation, antimicrobial activity, and application in various wound models (both in vitro and in vivo studies). Also, the clinical and commercial applications of LBNs are summarized.

Nature vs. Manmade: Comparing Exosomes and Liposomes for Traumatic Brain Injury

Traumatic brain injury (TBI) of all severities is a significant public health burden, causing a range of effects that can lead to death or a diminished quality of life. Liposomes and mesenchymal stem cell-derived exosomes are two drug delivery agents with potential to be leveraged in the treatment of TBI by increasing the efficacy of drug therapies as well as having additional therapeutic effects. They exhibit several physical similarities, but key differences affect their performances as nanocarriers. Liposomes can be produced commercially at scale, and liposomes achieve higher encapsulation efficiency. Meanwhile, the intrinsic cargo and targeting moieties of exosomes, which liposomes lack, give exosomes a greater ability to facilitate neural regeneration, and exosomes do not trigger the infusion reactions that liposomes can. However, there are concerns about both exosomes and liposomes regarding interactions with tumors. The same routes of administration can be used for both exosomes and liposomes, resulting in somewhat different distribution throughout the body. While the effect of the nanocarrier type on accumulation in the brain is not concrete, targeting leads to increased accumulation of both exosomes and liposomes in the brain, upon which on-demand release can be used for both drug deliverers. Although neither have been applied to TBI in humans, preclinical trials have shown their immense potential, as have clinical trials pertaining to other brain injuries and conditions. While questions remain, research thus far shows that the various differences make exosomes a better choice of nanocarrier for TBI.

Reduction of neutrophil extracellular traps accelerates inflammatory resolution and increases bone formation on titanium implants

Neutrophils are the most abundant immune cells in the blood and the first cells to be recruited to the biomaterial implantation site. Neutrophils are fundamental in recruiting mononuclear leukocytes to mount an immune response at the injury site. Neutrophils exert significant pro-inflammatory effects through the release of cytokines and chemokines, degranulation and release of myeloperoxidase (MPO) and neutrophil elastase (NE), and the production of large DNA-based networks called neutrophil extracellular traps (NETs). Neutrophils are initially recruited and activated by cytokines and pathogen- and damage-associated molecular patterns, but little is known about how the physicochemical composition of the biomaterial affects their activation. This study aimed to understand how ablating neutrophil mediators (MPO, NE, NETs) affected macrophage phenotype in vitro and osseointegration in vivo. We discovered that NET formation is a crucial mediator of pro-inflammatory macrophage activation, and inhibition of NET formation significantly suppresses macrophage pro-inflammatory phenotype. Furthermore, reducing NET formation accelerated the inflammatory phase of healing and produced greater bone formation around the implanted biomaterial, suggesting that NETs are essential regulators of biomaterial integration. Our findings emphasize the importance of the neutrophil response to implanted biomaterials and highlight innate immune cells' regulation and amplification signaling during the initiation and resolution of the inflammatory phase of biomaterial integration. STATEMENT OF SIGNIFICANCE: Neutrophils are the most abundant immune cells in blood and are the first to be recruited to the injury/implantation site where they exert significant pro-inflammatory effects. This study aimed to understand how ablating neutrophil mediators affected macrophage phenotype in vitro and bone apposition in vivo. We found that NET formation is a crucial mediator of pro-inflammatory macrophage activation. Reducing NET formation accelerated the inflammatory phase of healing and produced greater appositional bone formation around the implanted biomaterial, suggesting that NETs are essential regulators of biomaterial integration.

Chondroitin sulfate microspheres anchored with drug-loaded liposomes play a dual antioxidant role in the treatment of osteoarthritis

Reactive oxygen species (ROS) play a critical role in the pathogenesis of osteoarthritis. The injection of a single antioxidant drug is characterized by low drug utilization and short residence time in the articular cavity, limiting the therapeutic effect of antioxidant drugs on osteoarthritis. Currently, the drug circulation half-life can be extended using delivery vehicles such as liposomes and microspheres, which are widely used to treat diseases. In addition, the composite carriers of liposomes and hydrogel microspheres can combine the advantages of different material forms and show stronger plasticity and flexibility than traditional single carriers, which are expected to become new local drug delivery systems. Chondroitin sulfate, a sulfated glycosaminoglycan commonly found in native cartilage, has good antioxidant properties and degradability and is used to develop an injectable chondroitin sulfate hydrogel by covalent modification with photo-cross-linkable methacryloyl groups (ChsMA). Herein, ChsMA microgels anchored with liquiritin (LQ)-loaded liposomes (ChsMA@Lipo) were developed to delay the progression of osteoarthritis by dual antioxidation. On the one hand, the antioxidant drug LQ wrapped in ChsMA@Lipo microgels exhibits significant sustained-release kinetics due to the double obstruction of the lipid membrane and the hydrogel matrix network. On the other hand, ChsMA can eliminate ROS through degradation into chondroitin sulfate monomers by enzymes in vivo. Therefore, ChsMA@Lipo, as a degradable and dual antioxidant drug delivery platform, is a promising option for osteoarthritis treatment. STATEMENT OF SIGNIFICANCE: Compared with the traditional single carrier, the composite carriers of hydrogel microspheres and liposome can complement the advantages of different materials, which shows stronger plasticity and flexibility, and is expected to become a new and efficient drug delivery system. ChsMA@Lipo not only attenuates IL-1β-induced ECM degradation in chondrocytes but also inhibits the M1 macrophages polarization and the inflammasome activation. The obtained ChsMA@Lipo alleviates the progression of osteoarthritis in vivo, which is promising for osteoarthritis treatment.

Polymer-Modified Liposomes for Drug Delivery: From Fundamentals to Applications

Liposomes are highly advantageous platforms for drug delivery. To improve the colloidal stability and avoid rapid uptake by the mononuclear phagocytic system of conventional liposomes while controlling the release of encapsulated agents, modification of liposomes with well-designed polymers to modulate the physiological, particularly the interfacial properties of the drug carriers, has been intensively investigated. Briefly, polymers are incorporated into liposomes mainly using “grafting” or “coating”, defined according to the configuration of polymers at the surface. Polymer-modified liposomes preserve the advantages of liposomes as drug-delivery carriers and possess specific functionality from the polymers, such as long circulation, precise targeting, and stimulus-responsiveness, thereby resulting in improved pharmacokinetics, biodistribution, toxicity, and therapeutic efficacy. In this review, we summarize the progress in polymer-modified liposomes for drug delivery, focusing on the change in physiological properties of liposomes and factors influencing the overall therapeutic efficacy.

Tailoring Materials with Specific Wettability in Biomedical Engineering

As a fundamental feature of solid surfaces, wettability is playing an increasingly important role in our daily life. Benefitting from the inspiration of biological paradigms and the development in manufacturing technology, numerous wettability materials with elaborately designed surface topology and chemical compositions have been fabricated. Based on these advances, wettability materials have found broad technological implications in various fields ranging from academy, industry, agriculture to biomedical engineering. Among them, the practical applications of wettability materials in biomedical-related fields are receiving remarkable researches during the past decades because of the increasing attention to healthcare. In this review, the research progress of materials with specific wettability is discussed. After briefly introducing the underlying mechanisms, the fabrication strategies of artificial materials with specific wettability are described. The emphasis is put on the application progress of wettability biomaterials in biomedical engineering. The prospects for the future trend of wettability materials are also presented.

Role of stealth lipids in nanomedicine-based drug carriers

The domain of nanomedicine owns a wide-ranging variety of lipid-based drug carriers, and novel nanostructured drug carriersthat are further added to this range every year. The primary goal behind the exploration of any new lipid-based nanoformulation is the improvement of the therapeutic index of the concerned drug molecule along with minimization in the associated side-effects. However, for maintaining a sustained delivery of these intravenously injected lipoidal nanomedicines to the targeted tissues and organ systems in the body, longer circulation in the bloodstream, as well as their stability, are important. After administration, upon recognition as foreign entities in the body, these systems are rapidly cleared by the cells associated with the mononuclear phagocyte system. In order to provide these lipid-based systems with long circulation characteristics, techniques such as coating of the lipoidal surface with an inert polymeric material like polyethylene glycol (PEG) assists in imparting 'stealth properties' to these nanoformulations for avoiding recognition by the macrophages of the immune system. In this review, detailed importance is given to the hydrophilic PEG polymer and the role played by PEG-linked lipid polymers in the field of nanomedicine-based drug carriers. The typical structure and classification of stealth lipids, clinical utility, assemblage techniques, physicochemical characterization, and factors governing the in-vivo performance of the PEG-linked lipids containing formulations will be discussed. Eventually, the novel concept of accelerated blood clearance (ABC) phenomenon associated with the use of PEGylated therapeutics will be deliberated.

Recent Progress in Bioconjugation Strategies for Liposome-Mediated Drug Delivery

In nanoparticle (NP)-mediated drug delivery, liposomes are the most widely used drug carrier, and the only NP system currently approved by the FDA for clinical use, owing to their advantageous physicochemical properties and excellent biocompatibility. Recent advances in liposome technology have been focused on bioconjugation strategies to improve drug loading, targeting, and overall efficacy. In this review, we highlight recent literature reports (covering the last five years) focused on bioconjugation strategies for the enhancement of liposome-mediated drug delivery. These advances encompass the improvement of drug loading/incorporation and the specific targeting of liposomes to the site of interest/drug action. We conclude with a section highlighting the role of bioconjugation strategies in liposome systems currently being evaluated for clinical use and a forward-looking discussion of the field of liposomal drug delivery.

Anchoring Property of a Novel Hydrophilic Lipopolymer, HDAS-SHP, Post-Inserted in Preformed Liposomes

Polyethylene glycol (PEG)-phospholipids in long-circulating liposomes cause non-specific immune reactions; mainly attributable to negatively-charged phosphoryl s at the interface of PEG and phospholipid. We investigated a novel lipopolymer, by which a superhydrophilic polymer (SHP) is conjugated to a non-phospholipid N¹-(2-aminoethyl)-N⁴-hexadecyl-2-tetradecylsuccinamide (HDAS). The modification of preformed liposomes HDAS-SHP, HDAS-PEG₂₀₀₀, and DSPE-PEG₂₀₀₀ were performed by post-insertion techniques. The efficiency of post-insertion and desorption rates, from the liposome surface, were determined. HDAS-SHP micelles showed highly positive zeta potential (+28.4 mV); zeta potentials of DSPE-PEG₂₀₀₀ and HDAS-PEG₂₀₀₀ micelles were −34.4 mV, and −3.7 mV, respectively. Critical micelle concentration predicted amphiphilicity of HDAS-SHP (CMC 2.58 µM) as close to that of DSPE-PEG₂₀₀₀ (CMC 2.44 µM). Both HDAS-SHP and HDAS-PEG₂₀₀₀ post-inserted with comparable efficiency (79%, and 73%, respectively), but noticeably lower than DSPE-PEG₂₀₀₀ (90%). The desorption rate of HDAS-SHP was close to that of DSPE-PEG₂₀₀₀ (0.53%/h, and 0.45%/h, respectively); the desorption rate for HDAS-PEG₂₀₀₀ was slightly more at 0.67%/h. Compared to plain liposomes, both HDAS-SHP- and DSPE-PEG₂₀₀₀-liposomes showed significant leakage of encapsulated Na-fluorescein isothiocyanate (FITC) upon incubation with serum. At the same time, both modified liposomes were found to suppress serum levels of the complement proteins, Bb and C4d. We infer that HDAS-SHP is a viable alternative to commonly-used PEG-phospholipid derivatives for stealth purposes.

Surface Modification of Liposomes by a Lipopolymer Targeting Prostate Specific Membrane Antigen for Theranostic Delivery in Prostate Cancer

Prostate specific membrane antigen (PSMA) is a marker for diagnosis and targeted delivery of therapeutics to advanced/metastasized prostate cancer. We report a liposome-based system for theranostic delivery to PSMA-expressing (PSMA⁺) LNCaP cells. A lipopolymer (P³) comprising of PSMA ligand (PSMAL), polyethylene glycol (PEG₂₀₀₀), and palmitate was synthesized and post-inserted into the surface of preformed liposomes. These P³-liposomes were loaded with doxorubicin and radiolabeled with ^99mTc radionuclide to study their theranostic characteristics. Differential expression of PSMA on LNCaP and PC3 cells was confirmed by immunoblotting as well as by uptake of PSMAL labeled with ¹⁸F radionuclide. We found that the uptake of ^99mTc-labeled P³-liposomes by LNCaP cells was >3-fold higher than ^99mTc-labeled Plain-liposomes; the amount of doxorubicin delivered to LNCaP cells was also found to be >3-fold higher by P³-liposomes. Cell-based cytotoxicity assay results showed that doxorubicin-loaded P³-liposomes were significantly more toxic to LNCaP cells (p < 0.05), but not to PSMA-negative PC3 cells. Compared to doxorubicin-loaded Plain-liposomes, the IC₅₀ value of doxorubicin-loaded P³-liposomes was reduced by ~5-fold in LNCaP cells. Together, these results suggest that surface functionalization of liposomes with small PSMA-binding motifs, such as PSMAL, can provide a viable platform for specific delivery of theranostics to PSMA⁺ prostate cancer.

Short Peptide-Mediated Brain-Targeted Drug Delivery with Enhanced Immunocompatibility

Peptide ligands have been exploited as versatile tools to facilitate targeted delivery of nanocarriers. However, the effects of peptide ligands on immunocompatibility and therapeutic efficacy of liposomes remain intricate. Here, a short and stable brain targeted peptide ligand D8 was modified on the surface of doxorubicin-loaded liposomes (D8-sLip/DOX), demonstrating prolonged blood circulation and lower liver distribution in comparison to the long and stable D-peptide ligand ^DCDX-modified doxorubicin-loaded liposomes (^DCDX-sLip/DOX) by mitigating natural IgM absorption. Despite the improved pharmacokinetic profiles, D8-sLip/DOX exhibited comparable brain targeting capacity in ICR mice and antiglioblastoma efficacy to ^DCDX-sLip/DOX in nude mice bearing intracranial glioblastoma. However, dramatic accumulation of ^DCDX-sLip/DOX in liver (especially during the first 8 h after intravenous injection) resulted in pathological symptoms, including nuclei swelling, necrosis of liver cells, and inflammation. These results suggest that short peptide ligand-mediated brain-targeted drug delivery systems possessing enhanced immunocompatibility are promising to facilitate efficient brain transport with improved biosafety.

Enhanced immunocompatibility of ligand-targeted liposomes by attenuating natural IgM absorption

Targeting ligands are anticipated to facilitate the precise delivery of therapeutic agents to diseased tissues; however, they may also severely affect the interaction of nanocarriers with plasma proteins. Here, we study the immunocompatibility of brain-targeted liposomes, which inversely correlates with absorbed natural IgM. Modification of long, stable positively charged peptide ligands on liposomes is inclined to absorb natural IgM, leading to rapid clearance and enhanced immunogenicity. Small peptidomimetic D8 developed by computer-aided peptide design exhibits improved immunocompatibility by attenuating natural IgM absorption. The present study highlights the effects of peptide ligands on the formed protein corona and in vivo fate of liposomes. Stable positively charged peptide ligands play double-edged roles in targeted delivery, preserving in vivo bioactivities for binding receptors and long-term unfavorable interactions with the innate immune system. The development of D8 provides insights into how to rationally design immunocompatible drug delivery systems by modulating the protein corona composition.

Targeting ligands on drug carriers can trigger immune responses. Here, the authors modify liposomes with a peptidomimetic that preserves bioactivity of the nanocarrier in blood circulation and attenuates IgM absorption, thereby improving the immunocompatibility of brain-targeted liposomes.

Heparosan-coated liposomes for drug delivery

Liposomal encapsulation is a useful drug delivery strategy for small molecules, especially chemotherapeutic agents such as doxorubicin. Doxil® is a doxorubicin-containing liposome ("dox-liposome") that passively targets drug to tumors while reducing side effects caused by free drug permeating and poisoning healthy tissues. Polyethylene glycol (PEG) is the hydrophilic coating of Doxil® that protects the formulation from triggering the mononuclear phagocyte system (MPS). Evading the MPS prolongs dox-liposome circulation time thus increasing drug deposition at the tumor site. However, multiple doses of Doxil® sometimes activate an anti-PEG immune response that enhances liposome clearance from circulation and causes hypersensitivity, further limiting its effectiveness against disease. These side effects constrain the utility of PEG-coated liposomes in certain populations, justifying the need for investigation into alternative coatings that could improve drug delivery for better patient quality of life and outcome. We hypothesized that heparosan (HEP; [-4-GlcA-β1-4-GlcNAc-α1-]n) may serve as a PEG alternative for coating liposomes. HEP is a natural precursor to heparin biosynthesis in mammals. Also, bacteria expressing an HEP extracellular capsule during infection escape detection and are recognized as "self," not a foreign threat. By analogy, coating drug-carrying liposomes with HEP should camouflage the delivery vehicle from the MPS, extending circulation time and potentially avoiding immune-mediated clearance. In this study, we characterize the postmodification insertion of HEP-lipids into liposomes by dynamic light scattering and coarse-grain computer modeling, test HEP-lipid immunogenicity in rats, and compare the efficacy of drug delivered by HEP-coated liposomes to PEG-coated liposomes in a human breast cancer xenograft mouse model.

Enhanced Oral Delivery of Protein Drugs Using Zwitterion-Functionalized Nanoparticles to Overcome both the Diffusion and Absorption Barriers

Oral delivery of protein drugs based on nanoparticulate delivery system requires permeation of the nanoparticles through the mucus layer and subsequent absorption via epithelial cells. However, overcoming these two barriers requires very different or even contradictory surface properties of the nanocarriers, which greatly limits the oral bioavailability of macromolecular drugs. Here we report a simple zwitterions-based nanoparticle (NP) delivery platform, which showed a great potency in simultaneously overcoming both the mucus and epithelium barriers. The dense and hydrophilic coating of zwitterions endows the NPs with excellent mucus penetrating ability. Moreover, the zwitterions-based NPs also possessed excellent affinity with epithelial cells, which significantly improved (4.5-fold) the cellular uptake of DLPC NPs, compared to PEGylated NPs. Our results also indicated that this affinity was due to the interaction between zwitterions and the cell surface transporter PEPT1. Moreover, the developed NPs loaded with insulin could induce a prominent hypoglycemic response in diabetic rats following oral administration. These results suggest that zwitterions-based NPs might provide a new perspective for oral delivery of protein therapeutics.

Enhancing the pharmacokinetic/pharmacodynamic properties of therapeutic nucleotides using lipid nanoparticle systems

Although activity has been reported in vivo, free nucleic acid-based drugs are rapidly degraded and cleared following systemic administration. To address these challenges and improve the potency and bioavailability of genetic drugs, significant efforts have been made to develop effective delivery systems of which lipid nanoparticles (LNP) represent the most advanced technology currently available. In this review, we will describe and discuss the improvements to the pharmacokinetic and pharmacodynamic properties of nucleic acid-based drugs mediated by LNP delivery. It is envisioned that the significant improvements in potency and safety, largely driven by the development of LNP encapsulated siRNA drugs, will be translatable to other types of genetic drugs and enable the rapid development of potent molecular tools and drugs.