PEG–lipid micelles as drug carriers: physiochemical attributes, formulation principles and biological implication

Enhanced cellular internalization of near-infrared fluorescent single-walled carbon nanotubes facilitated by a transfection reagent

Functionalized single-walled carbon nanotubes (SWCNTs) hold immense potential for diverse biomedical applications due to their biocompatibility and optical properties, including near-infrared fluorescence. Specifically, SWCNTs have been utilized to target cells as a vehicle for drug delivery and gene therapy, and as sensors for various intracellular biomarkers. While the main internalization route of SWCNTs into cells is endocytosis, methods for enhancing the cellular uptake of SWCNTs are of great importance. In this research, we demonstrate the use of a transfecting reagent for promoting cell internalization of functionalized SWCNTs. We explore different types of SWCNT functionalization, namely single-stranded DNA (ssDNA) or polyethylene glycol (PEG)-lipids, and two different cell types, embryonic kidney cells and adenocarcinoma cells. We show that internalizing PEGylated functionalized SWCNTs is enhanced in the presence of the transfecting reagent, where the effect is more pronounced for negatively charged PEG-lipid. However, ssDNA-SWCNTs tend to form aggregates in the presence of the transfecting reagent, rendering it unsuitable for promoting internalization. For all cases, cellular uptake is visualized by near-infrared fluorescence microscopy, showing that the SWCNTs are typically localized within the lysosome. Generally, cellular internalization was higher in the adenocarcinoma cells, thereby paving new avenues for drug delivery and sensing in malignant cells.

Strategies to address key challenges of metallacycle/metallacage-based supramolecular coordination complexes in biomedical applications

Owing to their capacity for dynamically linking two or more functional molecules, supramolecular coordination complexes (SCCs), exemplified by two-dimensional (2D) metallacycles and three-dimensional (3D) metallacages, have gained increasing significance in biomedical applications. However, their inherent hydrophobicity and self-assembly driven by heavy metal ions present common challenges in their applications. These challenges can be overcome by enhancing the aqueous solubility and in vivo circulation stability of SCCs, alongside minimizing their side effects during treatment. Addressing these challenges is crucial for advancing the fundamental research of SCCs and their subsequent clinical translation. In this review, drawing on extensive contemporary research, we offer a thorough and systematic analysis of the strategies employed by SCCs to surmount these prevalent yet pivotal obstacles. Additionally, we explore further potential challenges and prospects for the broader application of SCCs in the biomedical field.

Preparation, Characterization, and Anti-Lung Cancer Activity of Tetrandrine-Loaded Stealth Liposomes

Background

Tetrandrine (Tet), a bisbenzylisoquinoline alkaloid, is a potential candidate for cancer chemotherapy. However, Tet has poor aqueous solubility and a short half-life, which limits its bioavailability and efficacy. Liposomes have been widely utilized to enhance the bioavailability and efficacy of drugs.

Methods

In this study, Tet-loaded stealth liposomes (S-LPs@Tet) were prepared by ethanol injection method. Furthermore, physicochemical characterisation, biopharmaceutical behaviour, therapeutic efficacy, and biocompatibility of S-LPs@Tet were assessed.

Results

The prepared S-LPs@Tet had an average particle size of 65.57 ± 1.60 nm, a surface charge of -0.61 ± 0.10 mV, and an encapsulation efficiency of 87.20% ± 1.30%. The S-LPs@Tet released Tet in a sustained manner, and the results demonstrated that the formulation remained stable for one month. More importantly, S-LPs significantly enhanced the inhibitory ability of Tet on the proliferation and migration of lung cancer cells, and enabled Tet to escape phagocytosis by immune cells. Furthermore, in vivo studies confirmed the potential for long-circulation and potent tumor-suppressive effects of S-LPs@Tet. Moreover, ex vivo and in vivo safety experiments demonstrated that the carrier material S-LPs exhibited superior biocompatibility.

Conclusion

Our research suggested that S-LPs@Tet has potential applications in lung cancer treatment.

A Stable Micellar Formulation of RAD001 for Intracerebroventricular Delivery and the Treatment of Alzheimer's Disease and Other Neurological Disorders

A large body of evidence, replicated in many mouse models of Alzheimer's disease (AD), supports the therapeutic efficacy of the oral mammalian target of rapamycin inhibitors (mTOR-Is). Our preliminary data show that intracerebroventricular (ICV) administration of everolimus (RAD001) soon after clinical onset greatly diminished cognitive impairment and the intracellular beta amyloid and neurofibrillary tangle load. However, RAD001 shows >90% degradation after 7 days in solution at body temperature, thus hampering the development of proper therapeutic regimens for patients. To overcome such a drawback, we developed a stable, liquid formulation of mTOR-Is by loading RAD001 into distearoylphosphatidylethanolamine-polyethylene glycol 2000 (DSPE-PEG2000) micelles using the thin layer evaporation method. The formulation showed efficient encapsulation of RAD001 and a homogeneous colloidal size and stabilised RAD001, with over 95% of activity preserved after 14 days at 37 °C with a total decay only occurring after 98 days. RAD001-loaded DSPE-PEG2000 micelles were unchanged when stored at 4 and 25 °C over the time period investigated. The obtained formulation may represent a suitable platform for expedited clinical translation and effective therapeutic regimens in AD and other neurological diseases.

Norcantharidin-Encapsulated C60-Modified Nanomicelles: A Potential Approach to Mitigate Cytotoxicity in Renal Cells and Simultaneously Enhance Anti-Tumor Activity in Hepatocellular Carcinoma Cells

OBJECTIVE

The objective of this study was to examine the preparation process of DSPE-PEG-C60/NCTD micelles and assess the impact of fullerenol (C60)-modified micelles on the nephrotoxicity and antitumor activity of NCTD.

METHOD

The micelles containing NCTD were prepared using the ultrasonic method and subsequently optimized and characterized. The cytotoxicity of micelles loaded with NCTD was assessed using the CCK-8 method on human hepatoma cell lines HepG2 and BEL-7402, as well as normal cell lines HK-2 and L02. Acridine orange/ethidium bromide (AO/EB) double staining and flow cytometry were employed to assess the impact of NCTD-loaded micelles on the apoptosis of the HK-2 cells and the HepG2 cells. Additionally, JC-1 fluorescence was utilized to quantify the alterations in mitochondrial membrane potential. The generation of reactive oxygen species (ROS) following micelle treatment was determined through 2',7'-dichlorofluorescein diacetate (DCFDA) staining.

RESULTS

The particle size distribution of the DSPE-PEG-C60/NCTD micelles was determined to be 91.57 nm (PDI = 0.231). The zeta potential of the micelles was found to be -13.8 mV. The encapsulation efficiency was measured to be 91.9%. The in vitro release behavior of the micelles followed the Higuchi equation. Cellular experiments demonstrated a notable decrease in the toxicity of the C60-modified micelles against the HK-2 cells, accompanied by an augmented inhibitory effect on cancer cells. Compared to the free NCTD group, the DSPE-PEG-C60 micelles exhibited a decreased apoptosis rate (12%) for the HK-2 cell line, lower than the apoptosis rate observed in the NCTD group (36%) at an NCTD concentration of 75 μM. The rate of apoptosis in the HepG2 cells exhibited a significant increase (49%), surpassing the apoptosis rate observed in the NCTD group (24%) at a concentration of 150 μM NCTD. The HK-2 cells exhibited a reduction in intracellular ROS and an increase in mitochondrial membrane potential (ΔψM) upon exposure to C60-modified micelles compared to the NCTD group.

CONCLUSIONS

The DSPE-PEG-C60/NCTD micelles, as prepared in this study, demonstrated the ability to decrease cytotoxicity and ROS levels in normal renal cells (HK-2) in vitro. Additionally, these micelles showed an enhanced antitumor activity against human hepatocellular carcinoma cells (HepG2, BEL-7402).

Immunogenicity of lipid nanoparticles and its impact on the efficacy of mRNA vaccines and therapeutics

Several studies have utilized a lipid nanoparticle delivery system to enhance the effectiveness of mRNA therapeutics and vaccines. However, these nanoparticles are recognized as foreign materials by the body and stimulate innate immunity, which in turn impacts adaptive immunity. Therefore, it is crucial to understand the specific type of innate immune response triggered by lipid nanoparticles. This article provides an overview of the immunological response in the body, explores how lipid nanoparticles activate the innate immune system, and examines the adverse effects and immunogenicity-related development pathways associated with these nanoparticles. Finally, we highlight and explore strategies for regulating the immunogenicity of lipid nanoparticles.

RNA nanotechnology: A new chapter in targeted therapy

Nanoparticles have been widely studied in the fields of biotechnology, pharmacy, optics and medicine and have broad application prospects. Numerous studies have shown significant interest in utilizing nanoparticles for chemically coating or coupling drugs, aiming to address the challenges of drug delivery, including degradability and uncertainty. Furthermore, the utilization of lipid nanoparticles loaded with novel coronavirus antigen mRNA to control the COVID-19 pandemic has led to a notable surge in research on nanoparticle vaccines. Hence, nanoparticles have emerged as a crucial delivery system for disease prevention and treatment, bearing immense significance. Current research highlights that nanoparticles offer superior efficacy and potential compared to conventional drug treatment and prevention methods. Notably, for drug delivery applications, it is imperative to utilize biodegradable nanoparticles. This paper reviews the structures and characteristics of various biodegradable nanoparticles and their applications in biomedicine in order to inspire more researchers to further explore the functions of nanoparticles. RNA plays a pivotal role in regulating the occurrence and progression of diseases, but its inherent susceptibility to degradation poses a challenge. In light of this, we conducted a comprehensive review of the research advancements concerning RNA-containing biodegradable nanoparticles in the realm of disease prevention and treatment, focusing on cancer, inflammatory diseases, and viral infections.

Endotyping of IgE-Mediated Polyethylene Glycol and/or Polysorbate 80 Allergy

BACKGROUND

Polyethylene glycol (PEG) and polysorbate 80 (PS80) allergy preclude from SARS-CoV-2 vaccination. The mechanism(s) governing cross-reactivity and PEG molecular weight dependence remain unclear.

OBJECTIVES

To evaluate PEGylated lipid nanoparticle (LNP) vaccine (BNT162b2) tolerance and explore the mechanism of reactivity in PEG and/or PS80 allergic patients.

METHODS

PEG/PS80 dual- (n = 3), PEG mono- (n = 7), and PS80 mono-allergic patients (n = 2) were included. Tolerability of graded vaccine challenges was assessed. Basophil activation testing on whole blood (wb-BAT) or passively sensitized donor basophils (allo-BAT) was performed using PEG, PS80, BNT162b2, and PEGylated lipids (ALC-0159). Serum PEG-specific IgE was measured in patients (n = 10) and controls (n = 15).

RESULTS

Graded BNT162b2 challenge in dual- and PEG mono-allergic patients (n = 3/group) was well tolerated and induced anti-spike IgG seroconversion. PS80 mono-allergic patients (n = 2/2) tolerated single-dose BNT162b2 vaccination. Wb-BAT reactivity to PEG-containing antigens was observed in dual- (n = 3/3) and PEG mono- (n = 2/3), but absent in PS80 mono-allergic patients (n = 0/2). BNT162b2 elicited the highest in vitro reactivity. BNT162b2 reactivity was IgE mediated, complement independent, and inhibited in allo-BAT by preincubation with short PEG motifs, or detergent-induced LNP degradation. PEG-specific IgE was only detectable in dual-allergic (n = 3/3) and PEG mono-allergic (n = 1/6) serum.

CONCLUSION

PEG and PS80 cross-reactivity is determined by IgE recognizing short PEG motifs, whereas PS80 mono-allergy is PEG-independent. PS80 skin test positivity in PEG allergics was associated with a severe and persistent phenotype, higher serum PEG-specific IgE levels, and enhanced BAT reactivity. Spherical PEG exposure via LNP enhances BAT sensitivity through increased avidity. All PEG and/or PS80 excipient allergic patients can safely receive SARS-CoV-2 vaccines.

Tumor Microenvironment Responsive Nanomicelle with Folic Acid Modification Co-Delivery of Doxorubicin/Shikonin for Triple Negative Breast Cancer Treatment

Triple negative breast cancer (TNBC), which has poor prognosis, easily develops drug resistance and metastasizes. In general, those TNBC characteristics are related to a high activation of the epithelial-mesenchymal transition (EMT) pathway, which is inhibited by shikonin (SKN). Therefore, the synergistic therapy of SKN and doxorubicin (DOX) will increase anti-tumor efficacy and reduce metastasis. In this study, we prepared the folic acid-linked PEG nanomicelle (NM) grafted with the DOX (denoted as FPD) to load the SKN. We prepared the SKN@FPD NM according to the effective ratio of dual drugs, where the drug loadings of DOX and SKN were 8.86 ± 0.21% and 9.43 ± 0.13%, with 121.8 ± 1.1 nm of its hydrodynamic dimension and 6.33 ± 0.16 mV of zeta potential, respectively. The nanomaterials significantly slowed down the release of DOX and SKN over 48 h, leading to the release of pH-responsive drugs. Meanwhile, the prepared NM inhibited the activity of MBA-MD-231 cells in vitro. Further in vitro study revealed that the SKN@FPD NM increased the DOX uptake and significantly reduced the metastasis of MBA-MD-231 cells. Overall, these active-targeting NMs improved the tumor-targeting of small molecular drugs and effectively treated TNBC.

Strategies to improve the physicochemical properties of peptide-based drugs

Peptides are a rapid-growing class of therapeutics with unique and desirable physicochemical properties. Due to disadvantages such as low membrane permeability and susceptibility to proteolytic degradation, peptide-based drugs have limited bioavailability, a short half-life, and rapid in vivo elimination. Various strategies can be applied to improve the physicochemical properties of peptide-based drugs to overcome limitations such as limited tissue residence time, metabolic instability, and low permeability. Applied strategies including backbone modifications, side chain modifications, conjugation with polymers, modification of peptide termini, fusion to albumin, conjugation with the Fc portion of antibodies, cyclization, stapled peptides, pseudopeptides, cell-penetrating peptide conjugates, conjugation with lipids, and encapsulation in nanocarriers are discussed.

Polysarcosine-based lipid formulations for intracranial delivery of mRNA

Messenger RNA (mRNA) is revolutionizing the future of therapeutics in a variety of diseases, including neurological disorders. Lipid formulations have shown to be an effective platform technology for mRNA delivery and are the basis for the approved mRNA vaccines. In many of these lipid formulations, polyethylene glycol (PEG)-functionalized lipid provides steric stabilization and thus plays a key role in improving the stability both ex vivo and in vivo. However, immune responses towards PEGylated lipids may compromise the use of those lipids in some applications (e.g., induction of antigen specific tolerance), or within sensitive tissues (e.g., central nervous system (CNS)). With respect to this issue, polysarcosine (pSar)-based lipopolymers were investigated as an alternative to PEG-lipid in mRNA lipoplexes for controlled intracerebral protein expression in this study. Four polysarcosine-lipids with defined sarcosine average molecular weight (M_n = 2 k, 5 k) and anchor diacyl chain length (m = 14, 18) were synthesized, and incorporated into cationic liposomes. We found that the content, pSar chain length and carbon tail lengths of pSar-lipids govern the transfection efficiency and biodistribution. Increasing carbon diacyl chain length of pSar-lipid led up to 4- and 6-fold lower protein expression in vitro. When the length of either pSar chain or lipid carbon tail increased, the transfection efficiency decreased while the circulation time was prolonged. mRNA lipoplexes containing 2.5% C14-pSar2k resulted in the highest mRNA translation in the brain of zebrafish embryos through intraventricular injection, while C18-pSar2k-liposomes showed a comparable circulation with DSPE-PEG2k-liposomes after systemic administration. To conclude, pSar-lipid enable efficient mRNA delivery, and can substitute PEG-lipids in lipid formulations for controlled protein expression within the CNS.

Image-guided drug delivery in nanosystem-based cancer therapies

The past decades have shown significant advancements in the development of solid tumor treatment. For instance, implementation of nanosystems for drug delivery has led to a reduction in side effects and improved delivery to the tumor region. However, clinical translation has faced challenges, as tumor drug levels are still considered to be inadequate. Interdisciplinary research has resulted in the development of more advanced drug delivery systems. These are coined "smart" due to the ability to be followed and actively manipulated in order to have better control over local drug release. Therefore, image-guided drug delivery can be a powerful strategy to improve drug activity at the target site. Being able to visualize the inflow of the administered smart nanosystem within the tumor gives the potential to determine the right moment to apply the facilitator to initiate drug release. Here we provide an overview of available nanosystems, imaging moieties, and imaging techniques. We discuss preclinical application of these smart drug delivery systems, the strength of image-guided drug delivery, and the future of personalized treatment.

Smart Polymeric Micelles for Anticancer Hydrophobic Drugs

Cancer has become one of the deadliest diseases in our society. Surgery accompanied by subsequent chemotherapy is the treatment most used to prolong or save the patient's life. Still, it carries secondary risks such as infections and thrombosis and causes cytotoxic effects in healthy tissues. Using nanocarriers such as smart polymer micelles is a promising alternative to avoid or minimize these problems. These nanostructured systems will be able to encapsulate hydrophilic and hydrophobic drugs through modified copolymers with various functional groups such as carboxyls, amines, hydroxyls, etc. The release of the drug occurs due to the structural degradation of these copolymers when they are subjected to endogenous (pH, redox reactions, and enzymatic activity) and exogenous (temperature, ultrasound, light, magnetic and electric field) stimuli. We did a systematic review of the efficacy of smart polymeric micelles as nanocarriers for anticancer drugs (doxorubicin, paclitaxel, docetaxel, lapatinib, cisplatin, adriamycin, and curcumin). For this reason, we evaluate the influence of the synthesis methods and the physicochemical properties of these systems that subsequently allow an effective encapsulation and release of the drug. On the other hand, we demonstrate how computational chemistry will enable us to guide and optimize the design of these micelles to carry out better experimental work.

Discrete Libraries of Amphiphilic Poly(ethylene glycol) Graft Copolymers: Synthesis, Assembly, and Bioactivity

Poly(ethylene glycol) (PEG) is an important and widely used polymer in biological and pharmaceutical applications for minimizing nonspecific binding while improving blood circulation for therapeutic/imaging agents. However, commercial PEG samples are polydisperse, which hampers detailed studies on chain length-dependent properties and potentially increases antibody responses in pharmaceutical applications. Here, we report a practical and scalable method to prepare libraries of discrete PEG analogues with a branched, nonlinear structure. These lipid-PEG derivatives have a monodisperse backbone with side chains containing a discrete number of ethylene glycol units (3 or 4) and unique functionalizable chain ends. Significantly, the branched, nonlinear structure is shown to allow for efficient nanoparticle assembly while reducing anti-PEG antibody recognition when compared to commercial polydisperse linear systems, such as DMG-PEG2000. By enabling the scalable synthesis of a broad library of graft copolymers, fundamental self-assembly properties can be understood and shown to directly correlate with the total number of PEG units, nature of the chain ends, and overall backbone length. These results illustrate the advantages of discrete macromolecules when compared to traditional disperse materials.

Co-immunomodulation of tumor and tumor-draining lymph node during in situ vaccination promotes antitumor immunity

In situ vaccination has demonstrated the feasibility of priming local immunity for systemic antitumor responses. Although direct intratumoral delivery of adjuvant is the mainstay, tumor-draining lymph nodes (TDLNs) also play essential roles in antitumor immunity. We report that directing an adjuvant to both tumors and TDLNs during in situ vaccination can induce robust antitumor responses. Conventional intratumoral dosing leads to tumor-limited delivery of agents; however, delivery to both tumors and TDLNs can be ensured through a micellar formation. The peritumoral delivery of micellar MEDI9197 (mcMEDI), a toll-like receptor 7/8 agonist, induced significantly stronger innate and adaptive immune responses than those on conventional dosing. Optimal dosing was crucial because excessive or insufficient accumulation of the adjuvant in the TDLNs compromised therapeutic efficacy. The combination of local mcMEDI therapy significantly improved the efficacy of systemic anti-programmed death receptor-1 therapy. These data suggest that rerouting adjuvants to tumors and TDLNs can augment the therapeutic efficacy of in situ vaccination.

One-Pot, One-Step Synthesis of Drug-Loaded Magnetic Multimicelle Aggregates

Lipid-based formulations provide a nanotechnology platform that is widely used in a variety of biomedical applications because it has several advantageous properties including biocompatibility, reduced toxicity, relative ease of surface modifications, and the possibility for efficient loading of drugs, biologics, and nanoparticles. A combination of lipid-based formulations with magnetic nanoparticles such as iron oxide was shown to be highly advantageous in a growing number of applications including magnet-mediated drug delivery and image-guided therapy. Currently, lipid-based formulations are prepared by multistep protocols. Simplification of the current multistep procedures can lead to a number of important technological advantages including significantly decreased processing time, higher reaction yield, better product reproducibility, and improved quality. Here, we introduce a one-pot, single-step synthesis of drug-loaded magnetic multimicelle aggregates (MaMAs), which is based on controlled flow infusion of an iron oxide nanoparticle/lipid mixture into an aqueous drug solution under ultrasonication. Furthermore, we prepared molecular-targeted MaMAs by directional antibody conjugation through an Fc moiety using Cu-free click chemistry. Fluorescence imaging and quantification confirmed that antibody-conjugated MaMAs showed high cell-specific targeting that was enhanced by magnetic delivery.

Predictive high-throughput screening of PEGylated lipids in oligonucleotide-loaded lipid nanoparticles for neuronal gene silencing

Lipid nanoparticles (LNPs) are gaining traction in the field of nucleic acid delivery following the success of two mRNA vaccines against COVID-19. As one of the constituent lipids on LNP surfaces, PEGylated lipids (PEG-lipids) play an important role in defining LNP physicochemical properties and biological interactions. Previous studies indicate that LNP performance is modulated by tuning PEG-lipid parameters including PEG size and architecture, carbon tail type and length, as well as the PEG-lipid molar ratio in LNPs. Owing to these numerous degrees of freedom, a high-throughput approach is necessary to fully understand LNP behavioral trends over a broad range of PEG-lipid variables. To this end, we report a low-volume, automated, high-throughput screening (HTS) workflow for the preparation, characterization, and in vitro assessment of LNPs loaded with a therapeutic antisense oligonucleotide (ASO). A library of 54 ASO-LNP formulations with distinct PEG-lipid compositions was prepared using a liquid handling robot and assessed for their physiochemical properties as well as gene silencing efficacy in murine cortical neurons. Our results show that the molar ratio of anionic PEG-lipid in LNPs regulates particle size and PEG-lipid carbon tail length controls ASO-LNP gene silencing activity. ASO-LNPs formulated using PEG-lipids with optimal carbon tail lengths achieved up to 5-fold lower mRNA expression in neurons as compared to naked ASO. Representative ASO-LNP formulations were further characterized using dose-response curves and small-angle X-ray scattering to understand structure-activity relationships. Identified hits were also tested for efficacy in primary murine microglia and were scaled-up using a microfluidic formulation technique, demonstrating a smooth translation of ASO-LNP properties and in vitro efficacy. The reported HTS workflow can be used to screen additional multivariate parameters of LNPs with significant time and material savings, therefore guiding the selection and scale-up of optimal formulations for nucleic acid delivery to a variety of cellular targets.

Wirelessly Activated Nanotherapeutics for In Vivo Programmable Photodynamic-Chemotherapy of Orthotopic Bladder Cancer

Photochemical internalization (PCI) is a promising intervention using photodynamic therapy (PDT) to enhance the activity of chemotherapeutic drugs. However, current bladder cancer treatments involve high-dose chemotherapy and high-irradiance PDT which cause debilitating side effects. Moreover, low penetration of light and drugs in target tissues and cumbersome light delivery procedures hinder the clinical utility of PDT and chemotherapy combination for PCI. To circumvent these challenges, a photodynamic-chemotherapy approach is developed comprising tumor-targeting glycosylated nanocarriers, coloaded with chlorin e6 (Ce6) and gemcitabine elaidate (GemE), and a miniaturized implantable wirelessly powered light-emitting diode (LED) as a light source. The device successfully delivers four weekly light doses to the bladder while the nanocarrier promoted the specific accumulation of drugs in tumors. This approach facilitates the combination of low-irradiance PDT (1 mW cm-2 ) and low-dose chemotherapy (≈1500× lower than clinical dose) which significantly cures and controls orthotopic disease burden (90% treated vs control, 35%) in mice, demonstrating a potential new bladder cancer treatment option.

Nanoparticle-Induced m6A RNA Modification: Detection Methods, Mechanisms and Applications

With the increasing application of nanoparticles (NPs) in medical and consumer applications, it is necessary to ensure their safety. As m⁶A (N⁶-methyladenosine) RNA modification is one of the most prevalent RNA modifications involved in many diseases and essential biological processes, the relationship between nanoparticles and m⁶A RNA modification for the modulation of these events has attracted substantial research interest. However, there is limited knowledge regarding the relationship between nanoparticles and m⁶A RNA modification, but evidence is beginning to emerge. Therefore, a summary of these aspects from current research on nanoparticle-induced m⁶A RNA modification is timely and significant. In this review, we highlight the roles of m⁶A RNA modification in the bioimpacts of nanoparticles and thus elaborate on the mechanisms of nanoparticle-induced m⁶A RNA modification. We also summarize the dynamic regulation and biofunctions of m⁶A RNA modification. Moreover, we emphasize recent advances in the application perspective of nanoparticle-induced m⁶A RNA modification in medication and toxicity of nanoparticles to provide a potential method to facilitate the design of nanoparticles by deliberately tuning m⁶A RNA modification.

Lipid Nanoparticles─From Liposomes to mRNA Vaccine Delivery, a Landscape of Research Diversity and Advancement

Lipid nanoparticles (LNPs) have emerged across the pharmaceutical industry as promising vehicles to deliver a variety of therapeutics. Currently in the spotlight as vital components of the COVID-19 mRNA vaccines, LNPs play a key role in effectively protecting and transporting mRNA to cells. Liposomes, an early version of LNPs, are a versatile nanomedicine delivery platform. A number of liposomal drugs have been approved and applied to medical practice. Subsequent generations of lipid nanocarriers, such as solid lipid nanoparticles, nanostructured lipid carriers, and cationic lipid-nucleic acid complexes, exhibit more complex architectures and enhanced physical stabilities. With their ability to encapsulate and deliver therapeutics to specific locations within the body and to release their contents at a desired time, LNPs provide a valuable platform for treatment of a variety of diseases. Here, we present a landscape of LNP-related scientific publications, including patents and journal articles, based on analysis of the CAS Content Collection, the largest human-curated collection of published scientific knowledge. Rising trends are identified, such as nanostructured lipid carriers and solid lipid nanoparticles becoming the preferred platforms for numerous formulations. Recent advancements in LNP formulations as drug delivery platforms, such as antitumor and nucleic acid therapeutics and vaccine delivery systems, are discussed. Challenges and growth opportunities are also evaluated in other areas, such as medical imaging, cosmetics, nutrition, and agrochemicals. This report is intended to serve as a useful resource for those interested in LNP nanotechnologies, their applications, and the global research effort for their development.

Novel Core-Shell Polyamine Phosphate Nanoparticles Self-Assembled from PEGylated Poly(allylamine hydrochloride) with Low Toxicity and Increased In Vivo Circulation Time

An approach for reducing toxicity and enhancing therapeutic potential of supramolecular polyamine phosphate nanoparticles (PANs) through PEGylation of polyamines before their assembly into nanoparticles is presented here. It is shown that the number of polyethylene glycol (PEG) chains for polyamine largely influence physico-chemical properties of PANs and their biological endpoints. Poly(allylamine hydrochloride) (PAH) are functionalized through carbodiimide chemistry with three ratios of PEG molecules per PAH chain: 0.1, 1, and 10. PEGylated PAH is then assembled into PANs by exposing the polymer to phosphate buffer solution. PANs decrease size and surface charge with increasing PEG ratios as evidenced by dynamic light scattering and zeta potential measurements, with the ten PEG/PAH ratio PANs having practically zero charge. Small angle X-ray scattering (SAXS) proves that PEG chains form a shell around a polyamine core, which is responsible for the screening of positive charges. MTT experiments show that the screening of amine groups decreases nanoparticle toxicity, with the lowest toxicity for the 10 PEG/PAH ratio. Fluorescence correlation spectroscopy (FCS) proves less interaction with proteins for PEGylated PANs. Positron emission tomography (PET) imaging of ¹⁸ F labelled PANs shows longer circulation time in healthy mice for PEGylated PANs than non-PEGylated ones.

PEG-modified gadolinium nanoparticles as contrast agents for in vivo micro-CT

Vascular research is largely performed in rodents with the goal of developing treatments for human disease. Micro-computed tomography (micro-CT) provides non-destructive three-dimensional imaging that can be used to study the vasculature of rodents. However, to distinguish vasculature from other soft tissues, long-circulating contrast agents are required. In this study, we demonstrated that poly(ethylene glycol) (PEG)-coated gadolinium nanoparticles can be used as a vascular contrast agent in micro-CT. The coated particles could be lyophilized and then redispersed in an aqueous solution to achieve 100 mg/mL of gadolinium. After an intravenous injection of the contrast agent into mice, micro-CT scans showed blood pool contrast enhancements of at least 200 HU for 30 min. Imaging and quantitative analysis of gadolinium in tissues showed the presence of contrast agent in clearance organs including the liver and spleen and very low amounts in other organs. In vitro cell culture experiments, subcutaneous injections, and analysis of mouse body weight suggested that the agents exhibited low toxicity. Histological analysis of tissues 5 days after injection of the contrast agent showed cytotoxicity in the spleen, but no abnormalities were observed in the liver, lungs, kidneys, and bladder.

Preparation and Characterization of Palladium Derivate-Loaded Micelle Formulation in Vitro as an Innovative Therapy Option against Non-Small Cell Lung Cancer Cells

Nanoparticles have been used in cancer treatments to target tumor and reduce side effects. In this study, we aimed to increase the effectiveness of palladium(II) complex [PdCl(terpy)](sac) ⋅ 2H₂ O, which previously showed anticancer potential, by preparing the nanoparticle formulation. An inhalable micellar dispersion containing a palladium(II) complex (PdNP) was prepared and its physicochemical characteristics were evaluated using in vitro tests. Morphology, size and surface charges of particle and loading/encapsulation efficiency of PdNP were analyzed by scanning electron microscopy, zeta sizer and inductively coupled plasma mass spectrometry while aerosol properties of PdNP were measured by the next generation impactor. A549 and H1299 non-small lung cancer cell types were used for cytotoxicity using SRB and ATP assays. Fluorescent staining and M30 antigen assay were carried out for cell death evaluation. Apoptosis was confirmed by flow cytometry analyses. SEM, particle size, and zeta potential results showed the particles have inhalable properties. The amount of the palladium(II) complex loaded into the particles was quantified which indicated high encapsulation efficiencies (97 %). The micellar dispersion expected to reach the alveolar region and the brachial region was determined 35 % and 47 %, respectively. PdNP showed an anti-growth effect by increasing reactive oxygen species that is followed by the induction of mitochondria-dependent apoptosis that is evidenced by pyknotic nuclei and M30 antigen level increments and disruption of polarization of membrane in mitochondria (Δψm). The results show that PdNP might be a promising inhalable novel complex to be used in non-small cell lung cancer, which warrants animal studies in further.

Extracellular vesicles for the treatment of central nervous system diseases

The interest in extracellular vesicles (EVs) increased during the last decade. It is now established that these vesicles play a role in the pathogenesis of central nervous system diseases (CNS), which explains why they are studied as biomarkers in these pathologies. On the other hand, EVs can also present therapeutic properties, often similar to their parent cells, as observed with mesenchymal stem cell-derived EVs. They can then be used as therapeutics, alone or combined with a bioactive molecule, for the treatment of CNS diseases, as they can cross the blood-brain barrier more easily than synthetic nanomedicines and are less immunogenic. A few clinical trials are currently on-going but there are still challenges to overcome for further clinical translation such as the scale-up of the production, the lack of standardization for isolation and characterization methods and the low encapsulation efficiency.

Cationic lipid nanoparticle production by microfluidization for siRNA delivery

Microfluidization has been investigated as a new, scalable, and basic component saving method to produce cationic lipid nanoparticles, in particular for the delivery of short interfering RNAs (siRNAs). The design of experiment (DoE) allowed to reach optimized characteristics in terms of nanocarrier size reduction and low polydispersity. The structure of cationic liposomes and siRNA-lipoplexes was characterized. The optimized preparation parameters were identified as three microfluidization passages at a pressure of 10,000 psi, with a thin film hydration volume of 4 ml. Microfluidized liposomes mean size was 160 nm, with a polydispersity index of 0.2-0.3 and a zeta potential of +40 mV to +60 mV. Positive versus negative charge ratio between the charges of the cationic lipid and the phosphate charges of the siRNAs is a key factor determining the structure and silencing efficacy of siRNA lipoplexes. At a (+/-) charge ratio of 8, a proportion of 88% of the siRNA was associated to microfluidized lipoplexes, which remained stable for one month. These lipoplexes exhibited moderate cytotoxicity and gene silencing efficacy, which should be further optimized.

Nanotechnology-based antiviral therapeutics

The host immune system is highly compromised in case of viral infections and relapses are very common. The capacity of the virus to destroy the host cell by liberating its own DNA or RNA and replicating inside the host cell poses challenges in the development of antiviral therapeutics. In recent years, many new technologies have been explored for diagnosis, prevention, and treatment of viral infections. Nanotechnology has emerged as one of the most promising technologies on account of its ability to deal with viral diseases in an effective manner, addressing the limitations of traditional antiviral medicines. It has not only helped us to overcome problems related to solubility and toxicity of drugs, but also imparted unique properties to drugs, which in turn has increased their potency and selectivity toward viral cells against the host cells. The initial part of the paper focuses on some important proteins of influenza, Ebola, HIV, herpes, Zika, dengue, and corona virus and those of the host cells important for their entry and replication into the host cells. This is followed by different types of nanomaterials which have served as delivery vehicles for the antiviral drugs. It includes various lipid-based, polymer-based, lipid-polymer hybrid-based, carbon-based, inorganic metal-based, surface-modified, and stimuli-sensitive nanomaterials and their application in antiviral therapeutics. The authors also highlight newer promising treatment approaches like nanotraps, nanorobots, nanobubbles, nanofibers, nanodiamonds, nanovaccines, and mathematical modeling for the future. The paper has been updated with the recent developments in nanotechnology-based approaches in view of the ongoing pandemic of COVID-19.Graphical abstract.

Lipid nanoparticle formulation of niclosamide (nano NCM) effectively inhibits SARS-CoV-2 replication in vitro

As exemplified by the COVID-19 pandemic, highly infective respiratory viruses can spread rapidly in the population because of lack of effective approaches to control viral replication and spread. Niclosamide (NCM) is an old anthelminthic drug (World Health Organization essential medicine list) with pleiotropic pharmacological activities. Several recent publications demonstrated that NCM has broad antiviral activities and potently inhibits viral replication, including replication of SARS-CoV-2, SARS-CoV, and dengue viruses. Unfortunately, NCM is almost completely insoluble in water, which limits its clinical use. We developed a cost-effective lipid nanoparticle formulation of NCM (nano NCM) using only FDA-approved excipient and demonstrated potency against SARS-CoV-2 infection in cells (Vero E6 and ACE2-expressing lung epithelium cells).

Automated high-throughput preparation and characterization of oligonucleotide-loaded lipid nanoparticles

Lipid nanoparticles (LNPs) are increasingly employed to improve delivery efficiency and therapeutic efficacy of nucleic acids. Various formulation parameters can affect the quality attributes of these nanoparticle formulations, but currently there is a lack of systemic screening approaches to address this challenge. Here, we developed an automated high-throughput screening (HTS) workflow for streamline preparation and analytical characterization of LNPs loaded with antisense oligonucleotides (ASOs) in a full 96-well plate within 3 hrs. ASO-loaded LNPs were formulated by an automated solvent-injection method using a robotic liquid handler, and assessed for particle size distribution, encapsulation efficiency, and stability with different formulation compositions and ASO loadings. Results indicated that the PEGylated lipid content significantly affected the particle size distribution, while the ionizable lipid / ASO charge ratio impacted the encapsulation efficiency of ASOs. Furthermore, results from our HTS approach correlated with those from the state-of-the-art scale-up method using a microfluidic formulator, therefore opening up a new avenue for robust formulation development and design of experiment methods, while reducing material usage by 10 folds, improving analytical outputs and accumulation of information by 100 folds.

DSPE-PEG polymers for improving pulmonary absorption of poorly absorbed macromolecules in rats and relative mechanism

OBJECTIVE

This study aims to investigate the potential of DSPE-PEG polymers (DSPE-PEG-OH and DSPE-PEG-SH) on improving absorption of poorly absorbable macromolecules via intrapulmonary administration and underlying mechanism.

METHODS

In situ pulmonary absorption experiments were performed to investigate the absorption of model compounds after intrapulmonary administration to rats. The local membrane damage induced by these DSPE-PEG polymers were evaluated based on morphological observation of lung tissues and measurement of biological toxic markers in bronchoalveolar lavage fluid (BALF) postintrapulmonary delivery of DSPE-PEG polymers to rats. The underlying enhancement mechanism of these polymers was explored by investigating their effects on the pulmonary membrane fluidity and gene expression of tight junction associated proteins with fluorescence polarization and western blotting, respectively.

RESULTS

Intrapulmonary delivery of these DSPE-PEG polymers significantly enhanced absorptions of poorly absorbed model drugs and did not induce serious damage to the pulmonary membranes of rats. Mechanistic studies demonstrated unaffected pulmonary membrane fluidity and up-regulated expression levels of tight junction-associated proteins by DSPE-PEG polymers, thus indicating that paracellular pathways might be included in the underlying mechanisms by which DSPE-PEG polymers exerted their enhancing actions on drug absorption.

CONCLUSIONS

These findings suggested that these DSPE-PEG polymers are potential for promoting absorptions of poorly absorbable macromolecules with no evidence of damage to the local pulmonary membranes of rats.Novelty statementIn this study, DSPE-PEG-OH and DSPE-PEG-SH polymers, two DSPE-PEG2000 conjugates with different terminal groups demonstrated significant promoting effects on the absorption of poorly absorbed macromolecular drugs after intrapulmonary delivery to rats, and did not induce serious damage to the pulmonary membranes of rats. These DSPE-PEG polymers could statistically downregulate expression levels of tight junction-associated proteins (ZO-1 and occludin), indicating the underlying mechanism by which these polymers exerted their absorption enhancing actions through pulmonary epithelial paracellular pathways. Thus, this study exhibited prospective potential of these DSPE-PEG polymers in developing into dosage forms with the aim to improve the poor bioavailability of some poorly absorbed macromolecular drugs.

AZD9291 Resistance Reversal Activity of a pH-Sensitive Nanocarrier Dual-Loaded with Chloroquine and FGFR1 Inhibitor in NSCLC

AZD9291 can effectively prolong survival of non-small cell lung cancer (NSCLC) patients. Unfortunately, the mechanism of its acquired drug resistance is largely unknown. This study shows that autophagy and fibroblast growth factor receptor 1 signaling pathways are both activated in AZD9291 resistant NSCLC, and inhibition of them, respectively, by chloroquine (CQ) and PD173074 can synergistically reverse AZD9291 resistance. Herein, a coloaded CQ and PD173074 pH-sensitive shell-core nanoparticles CP@NP-cRGD is developed to reverse AZD9291 resistance in NSCLC. CP@NP-cRGD has a high encapsulation rate and stability, and can effectively prevent the degradation of drugs in circulation process. CP@NP-cRGD can target tumor cells by enhanced permeability and retention effect and the cRGD peptide. The pH-sensitive CaP shell can realize lysosome escape and then release drugs successively. The combination of CP@NP-cRGD and AZD9291 significantly induces a higher rate of apoptosis, more G0/G1 phase arrest, and reduces proliferation of resistant cell lines by downregulation of p-ERK1/2 in vitro. CQ in CP@NP-cRGD can block protective autophagy induced by both AZD9291 and PD173074. CP@NP-cRGD combined with AZD9291 shows adequate tumor enrichment, low toxicity, and excellent antitumor effect in nude mice. It provides a novel multifunctional nanoparticle to overcome AZD9291 resistance for potential clinical applications.

Assessing the pharmacokinetics and toxicology of polymeric micelle conjugated therapeutics

Introduction: Analogous to nanocarriers such as nanoparticles, liposomes, nano lipoidal carriers, niosomes, and ethosomes, polymeric micelles have gained significance in the field of drug delivery. They have attracted scientists worldwide by their nanometric size, wide range of polymers available for building block synthesis, stability and potential to enhance the targeting and safety of drugs. Incorporation of drugs within the interior of polymeric micelles alters the drug pharmacokinetics, which generally results in increased efficiency.Areas covered: This review deals with the pharmacokinetics of various anti-neoplastic drugs loaded into micelles. The structure of polymeric micelles, polymers employed in their development and techniques involved will be discussed. This is followed by discussion on the pharmacokinetics of anti-cancer drugs loaded into polymeric micelles and the toxicity concerns associated.Expert opinion: Polymeric micelles are nanometeric carriers, with higher stability, polymeric flexibility and higher drug loading of poorly water-soluble drugs. These nanosystems help in increasing the bioavailability of drugs by encapsulating them within the hydrophobic core. The proper selection and design of the amphiphilic polymer for micelles is a crucial step as it decides the toxicity and the biocompatibility.

Doxorubicin-loaded pH-sensitive micelles: A promising alternative to enhance antitumor activity and reduce toxicity

Doxorubicin (DOX) is an anthracycline antibiotic widely used in the treatment of cancer, however, it is associated with the occurrence of adverse reactions that limits its clinical use. In this context, the encapsulation of DOX in micelles responsive to pH variations has shown to be a strategy for tumor delivery of the drug, with the potential to increase therapeutic efficacy and to reduce the toxic effects. In addition, radiolabeling nanoparticles with a radioactive isotope is of great use in preclinical studies, since it allows the in vivo monitoring of the nanostructure through the acquisition of quantitative images. Therefore, this study aimed to develop, characterize, and evaluate the antitumor activity of a pH-sensitive micelle composed of DSPE-PEG₂₀₀₀, oleic acid, and DOX. The micelles had a diameter of 13 nm, zeta potential near to neutrality, and high encapsulation percentage. The critical micellar concentration (CMC) was 1.4 × 10^-5 mol L^-1. The pH-sensitivity was confirmed in vitro through a drug release assay. Cytotoxicity studies confirmed that the encapsulation of DOX into the micelles did not impair the drug cytotoxic activity. Moreover, the incorporation of DSPE-PEG₂₀₀₀-DTPA into the micelles allowed it radiolabeling with the technetium-99 m in high yield and stability, permitting its use to monitor antitumor therapy. In this sense, the pH-sensitive micelles were able to inhibit tumor growth significantly when compared to non-pH-sensitive micelles and the free drug. in vivo toxicity evaluation in the zebrafish model revealed significantly lower toxicity of pH-sensitive micelles compared to the free drug. These results indicate that the developed formulation presents itself as a promising alternative to potentiate the treatment of tumors.

Nano drug delivery systems in upper gastrointestinal cancer therapy

Upper gastrointestinal (GI) carcinomas are characterized as one of the deadliest cancer types with the highest recurrence rates. Their treatment is challenging due to late diagnosis, early metastasis formation, resistance to systemic therapy and complicated surgeries performed in poorly accessible locations. Current cancer medication face deficiencies such as high toxicity and systemic side-effects due to the non-specific distribution of the drug agent. Nanomedicine has the potential to offer sophisticated therapeutic possibilities through adjusted delivery systems. This review aims to provide an overview of novel approaches and perspectives on nanoparticle (NP) drug delivery systems for gastrointestinal carcinomas. Present regimen for the treatment of upper GI carcinomas are described prior to detailing various NP drug delivery formulations and their current and potential role in GI cancer theranostics with a specific emphasis on targeted nanodelivery systems. To date, only a handful of NP systems have met the standard of care requirements for GI carcinoma patients. However, an increasing number of studies provide evidence supporting NP-based diagnostic and therapeutic tools. Future development and strategic use of NP-based drug formulations will be a hallmark in the treatment of various cancers. This article seeks to highlight the exciting potential of novel NPs for targeted cancer therapy in GI carcinomas and thus provide motivation for further research in this field.

Pharmacokinetic Research Progress of Anti-tumor Drugs Targeting for Pulmonary Administration

BACKGROUND

Cancer is a major problem that threatens human survival and has a high mortality rate. The traditional chemotherapy methods are mainly intravenous injection and oral administration, but have obvious toxic and side effects. Anti-tumor drugs for pulmonary administration can enhance drug targeting, increase local drug concentration, and reduce the damage to systemic organs, especially for the treatment of lung cancer.

METHODS

The articles on the pharmacokinetics of anti-tumor drugs targeting pulmonary administration were retrieved from the Pub Med database. This article mainly took lung cancer as an example and summarized the pharmacokinetic characteristics of anti-tumor drugs targeting for pulmonary administration contained in nanoparticles, dendrimers, liposomes and micelles.

RESULTS

The review shows that the pharmacokinetics process of pulmonary administration is associated with a drug carrier by increasing the deposition and release of drugs in the lung, and retarding the lung clearance rate. Among them, the surface of dendrimers could be readily modified, and polymer micelles have favorable loading efficiency. In the case of inhalation administration, liposomes exhibit more excellent lung retention properties compared to other non-lipid carriers. Therefore, the appropriate drug carrier is instrumental to increase the curative effect of anti-tumor drugs and reduce the toxic effect on surrounding healthy tissues or organs.

CONCLUSION

In the process of pulmonary administration, the carrier-embedded antitumor drugs have the characteristics of targeted and sustained release compared with non-packaging drugs, which provides a theoretical basis for the clinical rational formulation of chemotherapy regimens. However, there is currently a lack of comparative research between drug packaging materials, and more importantly, the development of safe and effective anti-tumor drugs targeting for pulmonary administration requires more data.

Antitumor Activity of a Novel Double-Targeted System for Folate Receptor-Mediated Delivery of Mitomycin C

In this study, we designed, formulated, and investigated the potential antitumor activity of a folate receptor (FR)-mediated double-targeted drug delivery system. The system comprised of the FR ligand folic acid (FA), glycine-phenylalanine-leucine-glycine (Gly-Phe-Leu-Gly, GFLG), which can be specifically cleaved by cathepsin B, and the anticancer drug mitomycin C (MMC). The antitumor effect of FA-GFLG-MMC was compared to that of MMC. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay revealed that FA-GFLG-MMC has a significantly higher inhibitory effect on HeLa, SiHa, and PC9 cells (high FR expression) than that on 16HBE and A549 cells (low FR expression). Furthermore, FA-GFLG-MMC inhibited cancer cell proliferation in a dose-dependent manner. Free MMC was toxic to both cancer and normal cells. Apoptosis of the HeLa, SiHa, and PC9 cells was higher than that of the A549 cells; however, the apoptotic effect on 16HBE cells was minimal. Proapoptotic protein bcl-2-associated X-protein (BAX) and antiapoptotic protein BCL-2 play critical roles in cellular defense and apoptotic signal transduction. BAX/BCL-2 ratio is used to determine the intensity of an apoptotic signal and assess whether a cell will survive or undergo apoptosis. BAX and BCL-2 expression in cells treated with 5 μM FA-GFLG-MMC was studied by Western blotting. FA-GFLG-MMC increased the BAX/BCL-2 ratio in HeLa, SiHa, and PC9 cells. The results show that FA-GFLG-MMC can effectively inhibit tumor cell proliferation by inducing apoptosis. Therefore, the system developed can enhance the delivery of anticancer drugs to cancer cells and thereby reduce their toxic effects on normal cells.

Bifunctional Therapeutic Application of Low-Frequency Ultrasound Associated with Zinc Phthalocyanine-Loaded Micelles

Purpose

Sonodynamic therapy (SDT) is a new therapeutic modality for the noninvasive cancer treatment based on the association of ultrasound and sonosensitizer drugs. Topical SDT requires the development of delivery systems to properly transport the sonosensitizer, such as zinc phthalocyanine (ZnPc), to the skin. In addition, the delivery system itself can participate in sonodynamic events and influence the therapeutic response. This study aimed to develop ZnPc-loaded micelle to evaluate its potential as a topical delivery system and as a cavitational agent for low-frequency ultrasound (LFU) application with the dual purpose of promoting ZnPc skin penetration and generating reactive oxygen species (ROS) for SDT.

Methods

ZnPc-loaded micelles were developed by the thin-film hydration method and optimized using the Quality by Design approach. Micelles’ influence on LFU-induced cavitation activity was measured by potassium iodide dosimeter and aluminum foil pits experiments. In vitro skin penetration of ZnPc was assessed after pretreatment of the skin with LFU and simultaneous LFU treatment using ZnPc-loaded micelles as coupling media followed by 6 h of passive permeation of ZnPc-loaded micelles. The singlet oxygen generation by LFU irradiation of the micelles was evaluated using two different hydrophilic probes. The lipid peroxidation of the skin was estimated using the malondialdehyde assay after skin treatment with simultaneous LFU using ZnPc-loaded micelles. The viability of the B16F10 melanoma cell line was evaluated using resazurin after treatment with different concentrations of ZnPc-loaded micelles irradiated or not with LFU.

Results

The micelles increased the solubility of ZnPc and augmented the LFU-induced cavitation activity in two times compared to water. After 6 h ZnPc-loaded micelles skin permeation, simultaneous LFU treatment increased the amount of ZnPc in the dermis by more than 40 times, when compared to non-LFU-mediated treatment, and by almost 5 times, when compared to LFU pretreatment protocol. The LFU irradiation of micelles induced the generation of singlet oxygen, and the lipoperoxidation of the skin treated with the simultaneous LFU was enhanced in three times in comparison to the non-LFU-treated skin. A significant reduction in cell viability following treatment with ZnPc-loaded micelles and LFU was observed compared to blank micelles and non-LFU-treated control groups.

Conclusion

LFU-irradiated mice can be a potential approach to skin cancer treatment by combining the functions of increasing drug penetration and ROS generation required for SDT.

Transdermal Delivery of Kidney-Targeting Nanoparticles Using Dissolvable Microneedles

INTRODUCTION

Chronic kidney disease (CKD) affects approximately 13% of the world's population and will lead to dialysis or kidney transplantation. Unfortunately, clinically available drugs for CKD show limited efficacy and toxic extrarenal side effects. Hence, there is a need to develop targeted delivery systems with enhanced kidney specificity that can also be combined with a patient-compliant administration route for such patients that need extended treatment. Towards this goal, kidney-targeted nanoparticles administered through transdermal microneedles (KNP/MN) is explored in this study.

METHODS

A KNP/MN patch was developed by incorporating folate-conjugated micelle nanoparticles into polyvinyl alcohol MN patches. Rhodamine B (RhB) was encapsulated into KNP as a model drug and evaluated for biocompatibility and binding with human renal epithelial cells. For MN, skin penetration efficiency was assessed using a Parafilm model, and penetration was imaged via scanning electron microscopy. In vivo, KNP/MN patches were applied on the backs of C57BL/6 wild type mice and biodistribution, organ morphology, and kidney function assessed.

RESULTS

KNP showed high biocompatibility and folate-dependent binding in vitro, validating KNP's targeting to folate receptors in vitro. Upon transdermal administration in vivo, KNP/MN patches dissolved within 30 min. At varying time points up to 48 h post-KNP/MN administration, higher accumulation of KNP was found in kidneys compared with MN that consisted of the non-targeting, control-NP. Histological evaluation demonstrated no signs of tissue damage, and kidney function markers, serum blood urea nitrogen and urine creatinine, were found to be within normal ranges, indicating preservation of kidney health.

CONCLUSIONS

Our studies show potential of KNP/MN patches as a non-invasive, self-administrable platform to direct therapies to the kidneys.

Cryogenically frozen PEGylated liposomes and micelles: Water penetration and polarity profiles

Poly(ethylene glycol) (PEG)-grafted lipid dispersions are widely investigated in fundamental and biotechnological research for their successful use in drug-delivery. Here, we consider mixtures of the bilayer-forming lipid dipalmitoylphosphatidylcholine (DPPC) with the micelle-forming lipid PEG:2000-phosphatidilethanolamine (PEG:2000-DPPE) fully hydrated in D₂O and measured at 77 K. Electron Spin Echo Envelope Modulation and continuous wave Electron Paramagnetic Resonance of chain-labelled lipids are employed to detect the extent of solvent permeation and the environmental polarity, respectively, across the hydrocarbon regions of the lipid assemblies. Sigmoidal water penetration and polarity profiles are described in sterically stabilized liposomes (SSL) formed at submicellar content of PEG:2000-DPPE incorporated in DPPC. Compared to DPPC bilayers, SSL show increased hydrophobicity at both the polar/apolar interface and the chain termini, and a broader transition that is shifted toward the interface. Solvent exposure and polarity decrease on going down the chain in PEG:2000-DPPE micelles. However, compared to SSL, polymer-lipid micelles show higher solvent permeation at any chain segment and the chain termini are accessible to water. In any sample, heterogeneity is found in H-bond formation between the spin-label nitroxide groups and the solvent molecules. The results at cryogenic temperature add new insights into the biophysico-chemical characterization of PEGylated lipid dispersions.

Surface Modification of Iron Oxide-Based Magnetic Nanoparticles for Cerebral Theranostics: Application and Prospection

Combining diagnosis with therapy, magnetic iron oxide nanoparticles (INOPs) act as an important vehicle for drug delivery. However, poor biocompatibility of INOPs limits their application. To improve the shortcomings, various surface modifications have been developed, including small molecules coatings, polymers coatings, lipid coatings and lipopolymer coatings. These surface modifications facilitate iron nanoparticles to cross the blood-brain-barrier, which is essential for diagnosis and treatments of brain diseases. Here we focus on the characteristics of different coated INOPs and their application in brain disease, particularly gliomas, Alzheimer's disease (AD) and Parkinson's disease (PD). Moreover, we summarize the current progress and expect to provide help for future researches.

Fenretinide-polyethylene glycol (PEG) conjugate with improved solubility enhanced cytotoxicity to cancer cell and potent in vivo efficacy

Fenretinide (4-HPR), a synthetic retinoid, has shown its antitumor activity in many tumor types with low cytotoxicity to normal cells and high clinical safety. However, the low water solubility limits its further biological applications. To increase solubility, 4-HPR was conjugated with methoxy polyethylene glycol carboxylic acid (mPEG_2K-COOH) by an ester linkage between the phenol hydroxyl of 4-HPR and the carboxyl of mPEG_2K-COOH. The 4-HPR-PEG_2K conjugate micelles had mean size of 76.70 ± 1.248 nm with a narrow distribution and a low critical micelle concentration. In vitro cytotoxicity studies showed the micelles have higher cytotoxicity to A2780s and MCF-7 cells. Its IC₅₀ was 4.7 and 4.1-fold lower than the free 4-HPR, respectively. Importantly, in vivo pharmacokinetic studies, the AUC of 4-HPR was found to be 2.3-fold higher in 4-HPR-PEG_2K micelles compared to free 4-HPR. And the 4-HPR-PEG_2K micelles had higher antitumor activity. Meanwhile, the histopathology analysis exhibited that the micellar treatment decreased the viability of A2780s cells and increased the level of induced apoptosis. Therefore, the enhanced activity of 4-HPR by the method of conjugation with mPEG_2K-COOH could hopefully provide new insights into the matter of ovarian cancer and breast cancer treatment.

Bioactivatable reactive oxygen species-sensitive nanoparticulate system for chemo-photodynamic therapy

Bioactivatable polymer nanoparticles (NPs) have attracted considerable attention as a prospective cancer therapy. Herein, we describe bioactivatable reactive oxygen species (ROS)-sensitive prodrug NPs designed to elicit spatiotemporally controlled, phototriggered chemo-photodynamic therapy. First, an effective anticancer agent, doxorubicin (DOX), was conjugated to poly(ethylene glycol) (PEG) via an ROS-responsive degradable thioketal (TK) linker. The resulting amphiphilic PEG-DOX conjugate (PEG-TK-DOX) self-assembled into a bioactivatable ROS-responsive NP system could efficiently encapsulate a hydrophobic photodynamic therapy (PDT) agent, pheophorbide A (PhA), with good colloidal stability and unimodal size distribution. Second, after the selective retention of NPs in the tumor, the site-specific release of DOX and PhA was spatiotemporally controlled, initially by endogenous ROS and subsequently by exogenous ROS produced during PDT. The locoregional treatment not only photoactivates PhA molecules to generate cytotoxic ROS but also triggers an ROS cascade, which accelerates the release of DOX and PhA via the ROS-mediated structural destruction of NPs, resulting in an enhanced anticancer therapeutic effect. This prodrug-NP system may function as an effective nanomedicine platform, working synergistically to maximize the efficacy of the combination of chemotherapy and photodynamic therapy with a remote-controlled release mechanism. STATEMENT OF SIGNIFICANCE: Photodynamic therapy (PDT) is a noninvasive therapy involving local ROS generation through the activation of photosensitizer (PS) molecules induced via external irradiation with near-infrared (NIR) light. Combinational therapies with PDT could synergistically enhance the therapeutic efficacy and overcome the limitations of monotherapy. In this study, we describe bioactivatable reactive oxygen species (ROS)-sensitive prodrug nanoparticles designed to elicit spatiotemporally controlled, photo triggered chemo-photodynamic therapy. Upon accumulation in tumor by enhanced permeation and retention (EPR) effect, the nanoparticles exhibited target-specific release of chemo-drug and photosensitizer in a spatiotemporally controlled cascade manner by endogenous ROS in the initial stage and the excessive production of exogenous ROS during PDT, leading to a further ROS cascade that accelerates the release of therapeutic cargo.

Micelles: Promising Ocular Drug Carriers for Anterior and Posterior Segment Diseases

Micelles have been studied in the targeting of drug substances to different tissues as a nano-sized delivery system for many years. Sustained drug release, ease of production, increased solubility, and bioavailability of drugs with low water solubility are the most important superiorites of micellar carriers. These advantages paved the way for the use of micelles as a drug delivery system in the ocular tissues. The unique anatomical structure of the eye as well as its natural barriers and physiology affect ocular bioavailability of the drugs negatively. Conventional dosage forms can only reach the anterior segment of the eye and are used for the treatment of diseases of this segment. In the treatment of posterior segment diseases, conventional dosage forms are administered sclerally, via an intravitreal injection, or systemically. However, ocular irritation, low patient compliance, and high side effects are also observed. Micellar ocular drug delivery systems have significant promise for the treatment of ocular diseases. The potential of micellar systems ocular drug delivery has been demonstrated by in vivo animal experiments and clinical studies, and they are continuing extensively. In this review, the recent research studies, in which the positive outcomes of micelles for ocular targeting of drugs for both anterior and posterior segment diseases as well as glaucoma has been demonstrated by in vitro, ex vivo, or in vivo studies, are highlighted.

Targeting heme-oxidized soluble guanylate cyclase to promote osteoblast function

The enzyme soluble guanylate cyclase (sGC) plays an essential part in the nitric oxide (NO) signaling pathway by binding to the prosthetic heme group; thereby catalyzing the synthesis of cyclic guanosine monophosphate (cGMP)-dependent protein kinases. Impaired NO-sGC-cGMP signaling could lead to osteoblast apoptosis by mechanisms involving the oxidative-stress-induced shift of the redox state of the reduced heme to oxidized sGC, leading to diminished heme binding to the enzyme and rendering the sGC unresponsive to NO. Targeting oxidized sGC to enhance cGMP production could restore proliferation and differentiation of osteoblasts into osteocytes. Here, the potential role of sGC activators of an oxidized or heme-free sGC as a target for promoting osteoblast function is reviewed and strategies for delivering drugs to bone are identified.

pH-Sensitive Shell-Core Platform Block DNA Repair Pathway To Amplify Irreversible DNA Damage of Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) is insensitive to either chemotherapy or endocrine therapy because of the powerful DNA reparation and the negative expression of surface antigens, which urgently claims for an effective approach to improve the prognosis. Herein, DNA repair blocker BRCA1 small interfering RNA (siRNA) was introduced with cisplatin (Pt) into the elaborately designed pH-sensitive shell-core platform to enhance the chemotherapeutic treatment effect by silencing the DNA repair related gene. In this platform, BRCA1 siRNA and Pt prodrug (Pro-Pt) were separately encapsulated in the porous outer shell and hydrophobic inner core with extremely high encapsulation efficiency and stability effectively preventing them from degradation during circulation. Suitable size and urokinase plasminogen activator analogues (uPA) with high affinity for the uPA receptor (uPAR) realized an excellent dual passive and active tumor targeting ability. Moreover, the exposed PEG hydrophilic chain prevented the nanoparticles (NPs) from precipitating by serum protein or inactivating by nuclease in the blood cycle. Most importantly, the degradable CaP (calcium ions and phosphate ions) shell with smart pH sensitivity would dissipate from NPs in the lysosomes to burst the lysosome membranes so as to guarantee the lysosomal escape and the sequential release of the siRNA and Pro-Pt where the BRCA1 siRNA blocked the DNA repairing pathway followed by reducing Pro-Pt to Pt for irreversible DNA damage. Hence, the uPA-SP@CaP NPs provided a promising strategy for high-efficiency treatment of TNBC along with bringing new hope for more patients.

Linolenic acid-modified MPEG-PEI micelles for encapsulation of amphotericin B

Aim: To encapsulate amphotericin B (AmB) with reduced toxicity and comparable activity. Results & methodology: The α-linolenic acid (ALA)-modified monomethoxy polyethylene glycol-g-PEI-g-ALA conjugate was employed to prepare AmB-loaded micelles (AmB-M). In vitro activity and release behavior of AmB-M were investigated. AmB-M enhanced AmB's water-solubility to 1.2 mg/ml, showing good storage stability. AmB-M could achieve a sustained and slow release of AmB, low hemolysis activity and negligible kidney toxicity when compared with commercial AmB injection. Antifungal activity and biofilm inhibition experiments confirmed that the antifungal activity of AmB-M against Candida albicans was similar to that of AmB injection. Conclusion: Monomethoxy polyethylene glycol-g-PEI-g-ALA micelles could be a preferable choice to treat systemic fungal infections as an efficient drug delivery system.

Improving glioblastoma therapeutic outcomes via doxorubicin-loaded nanomicelles modified with borneol

Glioblastoma is a grade IV malignant glioma with high recurrence and metastasis and faces a therapeutic obstacle that the blood-brain barrier (BBB) severely hinders the brain entry and efficacy of therapeutic drugs. Previous studies suggest that borneol (BO) has been used to enhance interested drugs to penetrate the BBB. In this study, a borneol-modified nanomicelle delivery system was established to facilitate the brain entry of doxorubicin for glioblastoma therapy. Herein, we firstly conjugated borneol molecules with DSPE-PEG₂₀₀₀-COOH to synthesize a novel carrier DSPE-PEG₂₀₀₀-BO and also characterized its structure. Doxorubicin-loaded nanomicelles (DOX BO-PMs) were prepared using DSPE-PEG₂₀₀₀-BO via electrostatic interaction and the physicochemical properties were investigated. The average particle size and zeta potential of DOX BO-PMs were respectively (14.95 ± 0.17)nm and (-1.27 ± 0.06)mV, and the drug encapsulation efficiency and loading capacity in DOX BO-PMs were (95.69 ± 0.49)% and (14.62 ± 0.39)%, respectively. The drug release of the DOX BO-PMs exhibited a both time- and pH-dependent pattern. The results demonstrated that DOX BO-PMs significantly enhanced the transport efficiency of DOX across the BBB and also exhibited a quick accumulation in the brain tissues. The in vitro anti-proliferation assay results suggested that DOX BO-PMs exerted a strong inhibitory effect on proliferation of glioblastoma cells. Importantly, in vivo antitumor results demonstrated that DOX BO-PMs significantly inhibited the tumor growth and metastasis of glioblastoma. In conclusion, DOX BO-PMs can improve the glioblastoma therapeutic outcomes and become a promising nanodrug candidate for the application of doxorubicin in the field of glioblastoma therapy.

Long-Circulating Amphiphilic Doxorubicin for Tumor Mitochondria-Specific Targeting

The mitochondria have emerged as a novel target for cancer chemotherapy primarily due to their central roles in energy metabolism and apoptosis regulation. Here, we report a new molecular approach to achieve high levels of tumor- and mitochondria-selective deliveries of the anticancer drug doxorubicin. This is achieved by molecular engineering, which functionalizes doxorubicin with a hydrophobic lipid tail conjugated by a solubility-promoting poly(ethylene glycol) polymer (amphiphilic doxorubicin or amph-DOX). In vivo, the amphiphile conjugated to doxorubicin exhibits a dual function: (i) it binds avidly to serum albumin and hijacks albumin's circulating and transporting pathways, resulting in prolonged circulation in blood, increased accumulation in tumor, and reduced exposure to the heart; (ii) it also redirects doxorubicin to mitochondria by altering the drug molecule's intracellular sorting and transportation routes. Efficient mitochondrial targeting with amph-DOX causes a significant increase of reactive oxygen species levels in tumor cells, resulting in markedly improved antitumor efficacy than the unmodified doxorubicin. Amphiphilic modification provides a simple strategy to simultaneously increase the efficacy and safety of doxorubicin in cancer chemotherapy.

Effect of CCR2 inhibitor-loaded lipid micelles on inflammatory cell migration and cardiac function after myocardial infarction

Background

After myocardial infarction (MI), inflammatory cells infiltrate the infarcted heart in response to secreted stimuli. Monocytes are recruited to the infarct via CCR2 chemokine receptors along a CCL2 concentration gradient. While infiltration of injured tissue with monocytes is an important component of the reparatory response, excessive or prolonged inflammation can adversely affect left ventricular remodeling and worsen clinical outcomes.

Materials and methods

Here, we developed poly(ethylene glycol) (PEG)-distearoylphos-phatidylethanolamine (PEG-DSPE) micelles loaded with a small molecule CCR2 antagonist to inhibit monocyte recruitment to the infarcted myocardium. To specifically target CCR2-expressing cells, PEG-DSPE micelles were further surface decorated with an anti-CCR2 antibody.

Results

Targeted PEG-DSPE micelles showed eight-fold greater binding to CCR2-expressing RAW 264.7 monocytes than plain, non-targeted PEG-DSPE micelles. In a mouse model of MI, CCR2-targeting PEG-DSPE micelles loaded with a CCR2 small molecule antagonist significantly decreased the number of Ly6C^high inflammatory cells to 3% of total compared with PBS-treated controls. Furthermore, CCR2-targeting PEG-DSPE micelles significantly reduced the infarct size based on epicardial and endocardial infarct arc lengths.

Conclusion

Both non-targeted and CCR2-targeting PEG-DSPE micelles showed a trend toward improving cardiac function. As such, PEG-DSPE micelles represent a promising cardiac therapeutic platform.