Thermosensitive liposomes for localized delivery and triggered release of chemotherapy

Factors affecting response variables with emphasis on drug release and loading for optimization of liposomes

Drug delivery through Liposomes has shown tremendous potential in terms of the therapeutic application of nanoparticles. There are several drug-loaded liposomal formulations approved for clinical use that help mitigate harmful effects of life-threatening diseases. Developments in the field of liposomal formulations and drug delivery have made it possible for clinicians and researchers to find therapeutic solutions for complicated medical conditions. A key aspect in the development of drug-loaded liposomes is a careful review of optimization techniques to improve the overall formulation stability and efficacy. Optimization studies help in improving/modulating the various properties of drug-loaded liposomes and are vital for the development of this class of delivery systems. A comprehensive overview of the various process variables and factors involved in the optimization of drug-loaded liposomes is presented in this review. The influence of different independent variables on drug release and loading properties with the application of a statistical experimental design is also explained in this article.

Brain-Derived Neurotrophic Factor-Loaded Low-Temperature-Sensitive liposomes as a drug delivery system for repairing podocyte damage

Podocytes, cells of the glomerular filtration barrier, play a crucial role in kidney diseases and are gaining attention as potential targets for new therapies. Brain-Derived Neurotrophic Factor (BDNF) has shown promising results in repairing podocyte damage, but its efficacy via parenteral administration is limited by a short half-life. Low temperature sensitive liposomes (LTSL) are a promising tool for targeted BDNF delivery, preserving its activity after encapsulation. This study aimed to improve LTSL design for efficient BDNF encapsulation and targeted release to podocytes, while maintaining stability and biological activity, and exploiting the conjugation of targeting peptides. While cyclic RGD (cRGD) was used for targeting endothelial cells in vitro, a homing peptide (HITSLLS) was conjugated for more specific uptake by glomerular endothelial cells in vivo. BDNF-loaded LTSL successfully repaired cytoskeleton damage in podocytes and reduced albumin permeability in a glomerular co-culture model. cRGD conjugation enhanced endothelial cell targeting and uptake, highlighting an improved therapeutic effect when BDNF release was induced by thermoresponsive liposomal degradation. In vivo, targeted LTSL showed evidence of accumulation in the kidneys, and their BDNF delivery decreased proteinuria and ameliorated kidney histology. These findings highlight the potential of BDNF-LTSL formulations in restoring podocyte function and treating glomerular diseases.

Unravelling the in vivo dynamics of liposomes: Insights into biodistribution and cellular membrane interactions

Liposomes, as a colloidal drug delivery system dating back to the 1960s, remain a focal point of extensive research and stand as a highly efficient drug delivery method. The amalgamation of technological and biological advancements has propelled their evolution, elevating them to their current status. The key attributes of biodegradability and biocompatibility have been instrumental in driving substantial progress in liposome development. Demonstrating a remarkable ability to surmount barriers in drug absorption, enhance stability, and achieve targeted distribution within the body, liposomes have become pivotal in pharmaceutical research. In this comprehensive review, we delve into the intricate details of liposomal drug delivery systems, focusing specifically on their pharmacokinetics and cell membrane interactions via fusion, lipid exchange, endocytosis etc. Emphasizing the nuanced impact of various liposomal characteristics, we explore factors such as lipid composition, particle size, surface modifications, charge, dosage, and administration routes. By dissecting the multifaceted interactions between liposomes and biological barriers, including the reticuloendothelial system (RES), opsonization, enhanced permeability and retention (EPR) effect, ATP-binding cassette (ABC) phenomenon, and Complement Activation-Related Pseudoallergy (CARPA) effect, we provide a deeper understanding of liposomal behaviour in vivo. Furthermore, this review addresses the intricate challenges associated with translating liposomal technology into practical applications, offering insights into overcoming these hurdles. Additionally, we provide a comprehensive analysis of the clinical adoption and patent landscape of liposomes across diverse biomedical domains, shedding light on their potential implications for future research and therapeutic developments.

Magnetic Modulation of Biochemical Synthesis in Synthetic Cells

Synthetic cells can be constructed from diverse molecular components, without the design constraints associated with modifying 'living' biological systems. This can be exploited to generate cells with abiotic components, creating functionalities absent in biology. One example is magnetic responsiveness, the activation and modulation of encapsulated biochemical processes using a magnetic field, which is absent from existing synthetic cell designs. This is a critical oversight, as magnetic fields are uniquely bio-orthogonal, noninvasive, and highly penetrative. Here, we address this by producing artificial magneto-responsive organelles by coupling thermoresponsive membranes with hyperthermic Fe3O4 nanoparticles and embedding them in synthetic cells. Combining these systems enables synthetic cell microreactors to be built using a nested vesicle architecture, which can respond to alternating magnetic fields through in situ enzymatic catalysis. We also demonstrate the modulation of biochemical reactions by using different magnetic field strengths and the potential to tune the system using different lipid compositions. This platform could unlock a wide range of applications for synthetic cells as programmable micromachines in biomedicine and biotechnology.

Cellular Trojan Horse initiates bimetallic Fe-Cu MOF-mediated synergistic cuproptosis and ferroptosis against malignancies

Disruptions in metal balance can trigger a synergistic interplay of cuproptosis and ferroptosis, offering promising solutions to enduring challenges in oncology. Here, we have engineered a Cellular Trojan Horse, named MetaCell, which uses live neutrophils to stably internalize thermosensitive liposomal bimetallic Fe-Cu MOFs (Lip@Fe-Cu-MOFs). MetaCell can instigate cuproptosis and ferroptosis, thereby enhancing treatment efficacy. Mirroring the characteristics of neutrophils, MetaCell can evade the immune system and not only infiltrate tumors but also respond to inflammation by releasing therapeutic components, thereby surmounting traditional treatment barriers. Notably, Lip@Fe-Cu-MOFs demonstrate notable photothermal effects, inciting a targeted release of Fe-Cu-MOFs within cancer cells and amplifying the synergistic action of cuproptosis and ferroptosis. MetaCell has demonstrated promising treatment outcomes in tumor-bearing mice, effectively eliminating solid tumors and forestalling recurrence, leading to extended survival. This research provides great insights into the complex interplay between copper and iron homeostasis in malignancies, potentially paving the way for innovative approaches in cancer treatment.

Encapsulation and release of calcein from herceptin-conjugated eLiposomes

Achieving an optimal therapeutic level is crucial in effectively eradicating cancer cells during treatment. However, conventional chemotherapy-associated systemic administration of anticancer agents leads to many side effects. To achieve the desired control over the target site, active targeting of HER2-positive breast cancer cells can be achieved by conjugating liposomal vesicles with Human Epidermal growth factor Receptor 2 (HER2) and inducing release of the encapsulated drug using ultrasound. To further enhance the delivery efficiency, nanoemulsion droplets exhibiting responsiveness to low-frequency ultrasound are encapsulated within these lipid vesicles. In this study, we prepared four different liposomal formulations, namely pegylated liposomes, emulsion liposomes (eLiposomes), HER-conjugated liposomes, and HER-conjugated eLiposomes, each loaded with calcein and subjected to a thorough characterization process. Their sizes, phospholipid concentration, and amount of antibody conjugation were compared and analyzed. Cryogenic transmission electron microscopy was used to confirm the encapsulation of nanoemulsion droplets within the liposomes. The drug-releasing performance of Herceptin-conjugated eLiposomes was found to surpass that of other liposomal formulations with a notably higher calcein release and established it as a highly effective nanocarrier. The study showcases the efficacy of calcein-loaded and Herceptin-conjugated eLiposomes, which demonstrate rapid and efficient drug release among other liposomal formulations when subjected to ultrasound. This discovery paves the way for a more targeted, efficient, and humane approach to cancer therapy.

Nanoparticles as carriers of photosensitizers to improve photodynamic therapy in cancer

Photodynamic therapy (PDT) has emerged as a promising non invasive therapeutic approach for cancer treatment, offering unique advantages over conventional treatments. The combination of light activation and photosensitizing agents allows for targeted and localized destruction of cancer cells, reducing damage to surrounding healthy tissues. In recent years, the integration of nanoparticles with PDT has garnered significant attention due to their potential to enhance therapeutic outcomes. This review article aims to provide a comprehensive overview of the current state-of-the-art in utilizing nanoparticles for photodynamic therapy in cancer treatment. We summarized various nanoparticle-based approaches, their properties, and their implications in optimizing PDT efficacy, and discussed challenges and prospects in the field.

Metal-Phenolic Network with Pd Nanoparticle Nodes Synergizes Oxidase-Like and Photothermal Properties to Eradicate Oral Polymicrobial Biofilm-Associated Infections

Designing an effective treatment strategy to combat oral diseases caused by complex polymicrobial biofilms remains a great challenge. Herein, a series of metal-phenolic network with Pd nanoparticle nodes using polyphenols as stabilizers and reducing agents is constructed. Among them, sulfonated lignin-Pd (SLS-Pd) with ultrafine size palladium nanoparticles and broadband near infrared absorption exhibit excellent oxidase-like activity and stable photothermal effect. In vitro experiments demonstrate that the superoxide radical generated by SLS-Pd oxidase-like activity exhibits selective antibacterial effects, while its photothermal effect induced hyperthermia exhibits potent antifungal properties. This difference is further elucidated by RNA-sequencing analysis and all-atom simulation. Moreover, the SLS-Pd-mediated synergistic antimicrobial system exhibits remarkable efficacy in combating various biofilms and polymicrobial biofilms. By establishing a root canal model and an oropharyngeal candidiasis model, the feasibility of the synergistic antimicrobial system in treating oral biofilm-related infections is further validated. This system provides a promising therapeutic approach for polymicrobial biofilm-associated infections in the oral cavity.

The Impact of Nanomedicine on Soft Tissue Sarcoma Treated by Radiotherapy and/or Hyperthermia: A Review

This article presents a comprehensive review of nanoparticle-assisted treatment approaches for soft tissue sarcoma (STS). STS, a heterogeneous group of mesenchymal-origin tumors with aggressive behavior and low overall survival rates, necessitates the exploration of innovative therapeutic interventions. In contrast to conventional treatments like surgery, radiotherapy (RT), hyperthermia (HT), and chemotherapy, nanomedicine offers promising advancements in STS management. This review focuses on recent research in nanoparticle applications, including their role in enhancing RT and HT efficacy through improved drug delivery systems, novel radiosensitizers, and imaging agents. Reviewing the current state of nanoparticle-assisted therapies, this paper sheds light on their potential to revolutionize soft tissue sarcoma treatment and improve patient therapy outcomes.

Liposomes for drug delivery: review of vesicular composition, factors affecting drug release and drug loading in liposomes

Liposomes are considered among the most versatile and advanced nanoparticle delivery systems used to target drugs to specific cells and tissues. Structurally, liposomes are sphere-like vesicles of phospholipid molecules that are surrounded by equal number of aqueous compartments. The spherical shell encapsulates an aqueous interior which contains substances such as peptides and proteins, hormones, enzymes, antibiotics, antifungal and anticancer agents. This structural property of liposomes makes it an important nano-carrier for drug delivery. Extrusion is one of the most frequently used technique for preparing monodisperse uni-lamellar liposomes as the technique is used to control vesicle size. The process involves passage of lipid suspension through polycarbonate membrane with a fixed pore size to produce vesicles with a diameter near the pore size of the membrane used in preparing them. An advantage of this technique is that there is no need to remove the organic solvent or detergent from the final preparation. This review focuses on composition of liposome formulation with special emphasis on factors affecting drug release and drug-loading.

Thermoresponsive M1 macrophage-derived hybrid nanovesicles for improved in vivo tumor targeting

Despite the efforts and advances done in the last few decades, cancer still remains one of the main leading causes of death worldwide. Nanomedicine and in particular extracellular vesicles are one of the most potent tools to improve the effectiveness of anticancer therapies. In these attempts, the aim of this work is to realize a hybrid nanosystem through the fusion between the M1 macrophages-derived extracellular vesicles (EVs-M1) and thermoresponsive liposomes, in order to obtain a drug delivery system able to exploit the intrinsic tumor targeting capability of immune cells reflected on EVs and thermoresponsiveness of synthetic nanovesicles. The obtained nanocarrier has been physicochemically characterized, and the hybridization process has been validated by cytofluorimetric analysis, while the thermoresponsiveness was in vitro confirmed through the use of a fluorescent probe. Tumor targeting features of hybrid nanovesicles were in vivo investigated on melanoma-induced mice model monitoring the accumulation in tumor site through live imaging and confirmed by cytofluorimetric analysis, showing higher targeting properties of hybrid nanosystem compared to both liposomes and native EVs. These promising results confirmed the ability of this nanosystem to combine the advantages of both nanotechnologies, also highlighting their potential use as effective and safe personalized anticancer nanomedicine.

Targeted drug delivery systems for elemene in cancer therapy: The story thus far

Elemene (ELE) is a group of broad-spectrum anticancer active ingredients with low toxicity extracted from traditional Chinese medicines (TCMs), such as Curcumae Rhizoma and Curcuma Radix, which can exert antitumour activities by regulating various signal pathways and targets. However, the strong hydrophobicity, short half-life, low bioavailability and weak in vivo targeting ability of ELE restrict its use. Targeted drug delivery systems based on nanomaterials are among the most viable methods to overcome these shortcomings. In this review, we first summarize recent studies on the clinical uses of ELE as an adjunct antitumour drug. ELE-based combination strategies have great promise for enhancing efficacy, reducing adverse reactions, and improving patients' quality of life and immune function. Second, we summarize recent studies on the antitumour mechanisms of ELE and ELE-based combination strategies. The potential mechanisms include inducing pyroptosis and ferroptosis, promoting senescence, regulating METTL3-mediated m6A modification, suppressing the Warburg effect, and inducing apoptosis and cell cycle arrest. Most importantly, we comprehensively summarize studies on the combination of targeted drug delivery systems with ELE, including passively and actively targeted drug delivery systems, stimuli-responsive drug delivery systems, and codelivery systems for ELE combined with other therapies, which have great promise in improving drug bioavailability, increasing drug targeting ability, controlling drug release, enhancing drug efficacy, reducing drug adverse effects and reversing MDR. Our summary will provide a reference for the combination of TCMs such as ELE with advanced targeted drug delivery systems in the future.

Folate-Targeted Nanoliposomal Chemophototherapy

Light-responsive liposomes have been developed for the on-demand release of drugs. However, efficient delivery of chemotherapeutic drugs to tumor for cancer theranostics remains a challenge. Herein, folic acid (FA), an established ligand for targeted drug delivery, was used to decorate light-sensitive porphyrin-phospholipid (PoP) liposomes, which were assessed for FA-targeted chemophototherapy (CPT). PoP liposomes and FA-conjugated PoP liposomes were loaded with Doxorubicin (Dox), and physical properties were characterized. In vitro, FA-PoP liposomes that were incubated with FA receptor-overexpressing human KB cancer cells showed increased uptake compared to non-targeted PoP liposomes. Dox and PoP contributed towards chemophototherapy (CPT) in vitro, and PoP and FA-PoP liposomes induced cell killing. In vivo, mice bearing subcutaneous KB tumors treated with PoP or FA-PoP liposomes loaded with Dox, followed by 665 nm laser treatment, had delayed tumor growth and improved survival. Dox delivery to tumors increased following laser irradiation for both PoP and FA-PoP liposomes. Thus, while Dox-FA-PoP liposomes were effective following systemic administration and local light irradiation in this tumor model, the FA targeting moiety did not appear essential for anti-tumor responses.

Box-Behnken design of thermo-responsive nano-liposomes loaded with a platinum(iv) anticancer complex: evaluation of cytotoxicity and apoptotic pathways in triple negative breast cancer cells

Herein, thermo-responsive liposomes (TLs) loaded with Asp (Asp/TLs) were produced by self-assembling DPPC, DSPE-PEG2000, and cholesterol. The preparation variables were optimized using the Box-Behnken design (BBD). The optimized Asp/TLs exhibited an average particle size of 114.05 ± 1.56 nm, PDI of 0.15 ± 0.015, zeta potential of -15.24 ± 0.65 mV, and entrapment efficiency (EE%) of 84.08 ± 2.75%. In addition, under physiological conditions, Asp/TLs showed spherical shape, outstanding stability and thermo-triggered the release of Asp at 38 °C, reaching the maximum Asp release at 40 °C. The MTT assay showed that the optimal Asp/TLs exhibited the highest cytotoxic activity upon exposure to mild hyperthermia (40 °C) against the invasive triple-negative breast cancer cell line (MDA-MB-231) when compared to other preparations. The IC50 of Asp/TLs (40 °C) was estimated at 0.9 μg mL-1, while that of free Asp (40 °C) was 3.83 μg mL-1. As such, the optimal Asp/TLs were shown to increase the cytotoxic activity of Asp by 4-fold upon exposure to mild hyperthermia. The IC50 values of Asp and Asp/TLs without exposure to 40 °C were 6.6 μg mL-1 and 186 μg mL-1, respectively. This indicated that Asp was released only when placed at 40 °C. The apoptosis assay revealed that Asp/TLs (40 °C) caused a remarkable increase in the percentage of cell population among both the late apoptosis and necrosis quartiles, as well as a significant decline in the viable cell quartile (P ≤ 0.001) when compared to Asp (40 °C). Asp/TLs (40 °C) and Asp (40 °C) could stimulate the intrinsic apoptosis pathway by upregulating the apoptotic genes Bak and Bax, while downregulating the anti-apoptotic genes, BCL-xL and BCL-2. The free Asp (40 °C) increased the gene expression of Bak and Bax by 4.4- and 5.2-folds, while reducing the expression of BCL-xL and BCL-2 by 50% and 73%, respectively. The optimal Asp TLs (40 °C) manifested more potent effects as demonstrated by the upregulation of Bak, Bax, and P53 by 5.6-, 7.2-, and 1.3-folds, as well as the downregulation of BCL-xL and BCL-2 by 70% and 85%, respectively. As such, the optimal Asp TLs (40 °C) treatment displayed the most potent cytotoxic profile and induced both apoptosis and necrosis in MDA-MB-231.

Mechanoresponsive Drug Delivery Systems for Vascular Diseases

Mechanoresponsive drug delivery systems (DDS) have emerged as promising candidates to improve the current effectiveness and lower the side effects typically associated with direct drug administration in the context of vascular diseases. Despite tremendous research efforts to date, designing drug delivery systems able to respond to mechanical stimuli to potentially treat these diseases is still in its infancy. By understanding relevant biological forces emerging in healthy and pathological vascular endothelium, it is believed that better-informed design strategies can be deduced for the fabrication of simple-to-complex macromolecular assemblies capable of sensing mechanical forces. These responsive systems are discussed through insights into essential parameter design (composition, size, shape, and aggregation state) , as well as their functionalization with (macro)molecules that are intrinsically mechanoresponsive (e.g., mechanosensitive ion channels and mechanophores). Mechanical forces, including the pathological shear stress and exogenous stimuli (e.g., ultrasound, magnetic fields), used for the activation of mechanoresponsive DDS are also introduced, followed by in vitro and in vivo experimental models used to investigate and validate such novel therapies. Overall, this review aims to propose a fresh perspective through identified challenges and proposed solutions that could be of benefit for the further development of this exciting field.

Innovative Delivery and Release Systems for Antioxidants and Other Active Substances in the Treatment of Cancer

Cancer is one of the major diseases leading to death worldwide, and the fight against the disease is still challenging. Cancer diseases are usually associated with increased oxidative stress and the accumulation of reactive oxygen and nitrogen species as a result of metabolic alterations or signaling aberrations. While numerous antioxidants exhibit potential therapeutic properties, their clinical efficiency against cancer is limited and even unproven. Conventional anticancer antioxidants and drugs have, among others, the great disadvantage of low bioavailability, poor targeting efficiency, and serious side effects, constraining their use in the fight against diseases. Here, we review the rationale for and recent advances in potential delivery systems that could eventually be employed in clinical research on antioxidant therapy in cancer. We also review some of the various strategies aimed at enhancing the solubility of poorly water-soluble active drugs, including engineered delivery systems such as lipid-based, polymeric, and inorganic formulations. The use of cyclodextrins, micro- and nanoemulsions, and thermosensitive smart liposomes as useful systems for the delivery and release of poorly aqueous-soluble drugs, improving their bioactivity and stability, is also addressed. We also provide some details on their formulation processes and their use in a variety of medical applications. Finally, we briefly cover a case study specifically focused on the use of delivery systems to minimize oral cancer and associated dental problems.

Microfluidic fabricated bisdemethoxycurcumin thermosensitive liposome with enhanced antitumor effect

Bisdemethoxycurcumin (BDMC) is the main active ingredient that is isolated from Zingiberaceae plants, wherein it has excellent anti-tumor effects. However, insolubility in water limits its clinical application. Herein, we reported a microfluidic chip device that can load BDMC into the lipid bilayer to form BDMC thermosensitive liposome (BDMC TSL). The natural active ingredient glycyrrhizin was selected as the surfactant to improve solubility of BDMC. Particles of BDMC TSL had small size, homogenous size distribution, and enhanced cultimulative release in vitro. The anti-tumor effect of BDMC TSL on human hepatocellular carcinomas was investigated via 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method, live/dead staining, and flowcytometry. These results showed that the formulated liposome had a strong cancer cell inhibitory, and presented a dose-dependent inhibitory effect on migration. Further mechanistic studies showed that BDMC TSL combined with mild local hyperthermia could significantly upregulate B cell lymphoma 2 associated X protein levels and decrease B cell lymphoma 2 protein levels, thereby inducing cell apoptosis. The BDMC TSL that was fabricated via microfluidic device were decomposed under mild local hyperthermia, which could beneficially enhance the anti-tumor effect of raw insoluble materials and promote translation of liposome.

Liposomes in Cancer Therapy: How Did We Start and Where Are We Now

Since their first discovery in the 1960s by Alec Bangham, liposomes have been shown to be effective drug delivery systems for treating various cancers. Several liposome-based formulations received approval by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA), with many others in clinical trials. Liposomes have several advantages, including improved pharmacokinetic properties of the encapsulated drug, reduced systemic toxicity, extended circulation time, and targeted disposition in tumor sites due to the enhanced permeability and retention (EPR) mechanism. However, it is worth noting that despite their efficacy in treating various cancers, liposomes still have some potential toxicity and lack specific targeting and disposition. This explains, in part, why their translation into the clinic has progressed only incrementally, which poses the need for more research to focus on addressing such translational limitations. This review summarizes the main properties of liposomes, their current status in cancer therapy, and their limitations and challenges to achieving maximal therapeutic efficacy.

Recent Preclinical and Clinical Progress in Liposomal Doxorubicin

Doxorubicin (DOX) is a potent anti-cancer agent that has garnered great interest in research due to its high efficacy despite dose-limiting toxicities. Several strategies have been exploited to enhance the efficacy and safety profile of DOX. Liposomes are the most established approach. Despite the improvement in safety properties of liposomal encapsulated DOX (in Doxil and Myocet), the efficacy is not superior to conventional DOX. Functionalized (targeted) liposomes present a more effective system to deliver DOX to the tumor. Moreover, encapsulation of DOX in pH-sensitive liposomes (PSLs) or thermo-sensitive liposomes (TSLs) combined with local heating has improved DOX accumulation in the tumor. Lyso-thermosensitive liposomal DOX (LTLD), MM-302, and C225-immunoliposomal(IL)-DOX have reached clinical trials. Further functionalized PEGylated liposomal DOX (PLD), TSLs, and PSLs have been developed and evaluated in preclinical models. Most of these formulations improved the anti-tumor activity compared to the currently available liposomal DOX. However, the fast clearance, the optimization of ligand density, stability, and release rate need more investigations. Therefore, we reviewed the latest approaches applied to deliver DOX more efficiently to the tumor, preserving the benefits obtained from FDA-approved liposomes.

Acoustic-responsive carbon dioxide-loaded liposomes for efficient drug release

The role of liposomes as drug carriers has been investigated. Ultrasound-based drug release methods have been developed for on-demand drug delivery. However, the acoustic responses of current liposome carriers result in low drug release efficiency. In this study, CO₂-loaded liposomes were synthesized under high pressure from supercritical CO₂ and irradiated with ultrasound at 237 kHz to demonstrate their superior acoustic responsiveness. When liposomes containing fluorescent drug models were irradiated with ultrasound under acoustic pressure conditions that are safe for the human body, CO₂-loaded liposomes synthesized using supercritical CO₂ had 17.1 times higher release efficiency than liposomes synthesized using the conventional Bangham method. In particular, the release efficiency of CO₂-loaded liposomes synthesized using supercritical CO₂ and monoethanolamine was 19.8 times higher than liposomes synthesized using the conventional Bangham method. These findings on the release efficiency of acoustic-responsive liposomes suggest an alternative liposome synthesis strategy for on-demand release of drugs by ultrasound irradiation in future therapies.

Preparation and Evaluation of Thermosensitive Liposomes Encapsulating I-125-Labeled Doxorubicin Derivatives for Auger Electron Therapy

Auger electrons (AEs) are very low-energy electrons emitted by radionuclides such as I-125 (¹²⁵I). This energy is deposited across a small distance (<0.5 μm), resulting in high linear energy transfer that is potent for causing lethal damage to cancer cells. Thus, AE-emitting radiotherapeutic agents have great potential for cancer treatment. In this study, thermosensitive liposomes (TSLs) encapsulating ¹²⁵I-labeled doxorubicin (DOX) derivatives were developed for Auger electron therapy, targeting the DNA of cancer cells. A radioiodinated DOX derivative [¹²⁵I]5 highly accumulated in the nuclei of cancer cells and showed potent cytotoxicity against Colon 26 cancer cells by AEs. Subsequently, [¹²⁵I]5 was loaded into the TSLs with high encapsulation efficiency. Potent release of [¹²⁵I]5 from TSLs was achieved with heating, whereas a decreased release was observed without heating. Furthermore, TSLs encapsulating [¹²⁵I]5 showed a high uptake in the nuclei at 42 °C for 1 h. We supposed that [¹²⁵I]5 was released by heating at 42 °C and accumulated in the nuclei in the cells. These results suggest that the combination of TSLs encapsulating [¹²⁵I]5 and hyperthermia is an effective cancer therapy.

Recent Advances in Photoacoustic Agents for Theranostic Applications

Photoacoustic agents are widely used in various theranostic applications. By evaluating the biodistribution obtained from photoacoustic images, the effectiveness of theranostic agents in terms of their delivery efficiency and treatment responses can be analyzed. Through this study, we evaluate and summarize the recent advances in photoacoustic-guided phototherapy, particularly in photothermal and photodynamic therapy. This overview can guide the future directions for theranostic development. Because of the recent applications of photoacoustic imaging in clinical trials, theranostic agents with photoacoustic monitoring have the potential to be translated into the clinical world.

Liposomes for Tumor Targeted Therapy: A Review

Liposomes, the most widely studied nano-drug carriers in drug delivery, are sphere-shaped vesicles consisting of one or more phospholipid bilayers. Compared with traditional drug delivery systems, liposomes exhibit prominent properties that include targeted delivery, high biocompatibility, biodegradability, easy functionalization, low toxicity, improvements in the sustained release of the drug it carries and improved therapeutic indices. In the wake of the rapid development of nanotechnology, the studies of liposome composition have become increasingly extensive. The molecular diversity of liposome composition, which includes long-circulating PEGylated liposomes, ligand-functionalized liposomes, stimuli-responsive liposomes, and advanced cell membrane-coated biomimetic nanocarriers, endows their drug delivery with unique physiological functions. This review describes the composition, types and preparation methods of liposomes, and discusses their targeting strategies in cancer therapy.

Review of the Delivery Kinetics of Thermosensitive Liposomes

Thermosensitive liposomes (TSL) are triggered nanoparticles that release the encapsulated drug in response to hyperthermia. Combined with localized hyperthermia, TSL enabled loco-regional drug delivery to tumors with reduced systemic toxicities. More recent TSL formulations are based on intravascular triggered release, where drug release occurs within the microvasculature. Thus, this delivery strategy does not require enhanced permeability and retention (EPR). Compared to traditional nanoparticle drug delivery systems based on EPR with passive or active tumor targeting (typically <5%ID/g tumor), TSL can achieve superior tumor drug uptake (>10%ID/g tumor). Numerous TSL formulations have been combined with various drugs and hyperthermia devices in preclinical and clinical studies over the last four decades. Here, we review how the properties of TSL dictate delivery and discuss the advantages of rapid drug release from TSL. We show the benefits of selecting a drug with rapid extraction by tissue, and with quick cellular uptake. Furthermore, the optimal characteristics of hyperthermia devices are reviewed, and impact of tumor biology and cancer cell characteristics are discussed. Thus, this review provides guidelines on how to improve drug delivery with TSL by optimizing the combination of TSL, drug, and hyperthermia method. Many of the concepts discussed are applicable to a variety of other triggered drug delivery systems.

Photoresponsive polymeric microneedles: An innovative way to monitor and treat diseases

Microneedles (MN) technology is an emerging technology for the transdermal delivery of therapeutics. When combined with photoresponsive (PR) materials, MNs can deliver therapeutics precisely and effectively with enhanced efficacy or synergistic effects. This review systematically summarizes the therapeutic applications of PRMNs in cancer therapy, wound healing, diabetes treatment, and diagnostics. Different PR approaches to activate and control the release of therapeutic agents from MNs are also discussed. Overall, PRMNs are a powerful tool for stimuli-responsive controlled-release therapeutic delivery to treat various diseases.

Concomitant delivery of doxorubicin and cisplatin through liposome-based thermosensitive nanoparticles: perspective in the treatment of cancer in animal models

The temperature sensitive liposomal formulations are a promising tool to improve the therapeutic index of the drugs with minimal toxicity. The aim of this study was to investigate the potential of concomitant delivery of cisplatin (Cis) and doxorubicin (Dox) containing thermosensitive liposomes (TSLs) with mild hyperthermia against cancer in vitro and in vivo. The polyethylene glycol coated DPPC/DSPC, thermosensitive and DSPC, non-thermosensitive liposomes incorporating Cis and Dox were prepared and characterized. A conventional Differential Scanning Calorimetry (DSC) technique and Fourier Transform Infrared Spectroscopy (FT-IR) were applied to study drug-phospholipid interaction and compatibility. The chemotherapeutic efficacy of these formulations was evaluated in benzo[a]pyrene (BaP) induced fibrosarcoma under hyperthermic condition. The size diameter of prepared thermosensitive liposomes was measured to be 120 ± 10 nm. The DSC data exhibited the changes in the curves of DSPC + Dox and DSPC + Cis while comparing the pure DSPC and drugs. However, the FITR showed same spectrum of phospholipids and drugs individually and in the mixture as well. The data showed higher efficacy of Cis-Dox-TSL as 84% inhibition in tumor growth was recorded in this group of animals in hyperthermic condition. The Kaplan-Meir curve revealed, 100% and 80% survival of the animals in the groups treated with Cis-Dox-TSL under hyperthermia and Cis-Dox-NTSL without hyperthermia, respectively. However, Cis-TSL as well as Dox-TSL exhibited 50% survival, while only 20% survival was recorded in the groups of animals treated with Dox-NTSL and Cis-NTSL. The flow cytometry analysis revealed that Cis-Dox-NTSL augments the induction of apoptosis in the tumor cells which was recorded as 18%. As expected, Cis-Dox-TSL showed great potential as 39% of cells were measured as apoptotic cells, significantly very high in comparison to Cis-Dox-NTSL, Dox-TSL and Cis-TSL as well. The apoptotic analysis of the cells by flow cytometry clearly indicated the effect of hyperthermia during the treatment while Cis-Dox-TSL formulation was administered. Finally, the immunohistochemical analysis of the tumor tissues by confocal microscopy exhibited several fold increases in the expression of pAkt in the animals treated with vehicles in Sham-NTSL as well as Sham-TSL. However, Cis-Dox-TSL showed great reduction in the expression of Akt, as it declined by 11-fold. The results of the present study directed the role of concomitant delivery doxorubicin and cisplatin containing thermosensitive liposomes under hyperthermic conditions for the development of a novel therapeutic strategy for the treatment of cancer.

Smart Drug-Delivery System of Upconversion Nanoparticles Coated with Mesoporous Silica for Controlled Release

Drug-delivery vehicles have garnered immense interest in recent years due to unparalleled progress made in material science and nanomedicine. However, the development of stimuli-responsive devices with controllable drug-release systems (DRSs) is still in its nascent stage. In this paper, we designed a two-way controlled drug-release system that can be promoted and prolonged, using the external stimulation of near-infrared light (NIR) and protein coating. A hierarchical nanostructure was fabricated using upconversion nanoparticles (UCNPs)-mesoporous silica as the core-shell structure with protein lysozyme coating. The mesoporous silica shell provides abundant pores for the loading of drug molecules and a specific type of photosensitive molecules. The morphology and the physical properties of the nanostructures were thoroughly characterized. The results exhibited the uniform core-shell nanostructures of ~four UCNPs encapsulated in one mesoporous silica nanoparticle. The core-shell nanoparticles were in the spherical shape with an average size of 200 nm, average surface area of 446.54 m²/g, and pore size of 4.6 nm. Using doxorubicin (DOX), a chemotherapy agent as the drug model, we demonstrated that a novel DRS with capacity of smart modulation to promote or inhibit the drug release under NIR light and protein coating, respectively. Further, we demonstrated the therapeutic effect of the designed DRSs using breast cancer cells. The reported novel controlled DRS with dual functionality could have a promising potential for chemotherapy treatment of solid cancers.

Thermosensitive Liposomes Encapsulating Nedaplatin and Picoplatin Demonstrate Enhanced Cytotoxicity against Breast Cancer Cells

Thermosensitive liposomes (TSL) have been used for localized temperature-responsive release of chemotherapeutics into solid cancers, with a minimum of one invention currently in clinical trials (phase III). In this study, TSL was designed using a lipid blend comprising 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol, and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[maleimide(polyethylene glycol)-2000] (DSPE-PEG-2000) (molar ratio of 88:9:2.8:0.2). Either nedaplatin (ND) or p-sulfonatocalix[4]arene-nedaplatin was encapsulated in the aqueous inner layer of TSL to form (ND-TSL) or p-SC4-ND-TSL, respectively. The hydrophobic platinum-based drug picoplatin (P) was loaded into the external lipid bilayer of the TSL to develop P-TSL. The three nanosystems were studied in terms of size, PDI, surface charge, and on-shelf stability. Moreover, the entrapment efficiency (EE%) and release % at 37 and 40 °C were evaluated. In a 30 min in vitro release study, the maximum release of ND, p-SC4-ND, and picoplatin at 40 °C reached 74, 79, and 75%, respectively, compared to approximately 10% at 37 °C. This demonstrated temperature-triggered drug release from the TSL in all three developed systems. The designed TSL exhibited significant in vitro anticancer activity at 40 °C when tested on human mammary gland/breast adenocarcinoma cells (MDA-MB-231). The cytotoxicity of ND-TSL, p-SC4-ND-TSL, and P-TSL at 40 °C was approximately twice those observed at 37 °C. This study suggests that TSL is a promising nanoplatform for the temperature-triggered release of platinum-based drugs into cancer cells.

Doxorubicin Loaded Thermosensitive Magneto-Liposomes Obtained by a Gel Hydration Technique: Characterization and In Vitro Magneto-Chemotherapeutic Effect Assessment

The combination of magnetic hyperthermia with chemotherapy is considered a promising strategy in cancer therapy due to the synergy between the high temperatures and the chemotherapeutic effects, which can be further developed for targeted and remote-controlled drug release. In this paper we report a simple, rapid, and reproducible method for the preparation of thermosensitive magnetoliposomes (TsMLs) loaded with doxorubicin (DOX), consisting of a lipidic gel formation from a previously obtained water-in-oil microemulsion with fine aqueous droplets containing magnetic nanoparticles (MNPs) dispersed in an organic solution of thermosensitive lipids (transition temperature of ~43 °C), followed by the gel hydration with an aqueous solution of DOX. The obtained thermosensitive magnetoliposomes (TsMLs) were around 300 nm in diameter and exhibited 40% DOX incorporation efficiency. The most suitable MNPs to incorporate into the liposomal aqueous lumen were Zn ferrites, with a very low coercive field at 300 K (7 kA/m) close to the superparamagnetic regime, exhibiting a maximum absorption rate (SAR) of 1130 W/gFe when dispersed in water and 635 W/gFe when confined inside TsMLs. No toxicity of Zn ferrite MNPs or of TsMLs was noticed against the A459 cancer cell line after 48 h incubation over the tested concentration range. The passive release of DOX from the TsMLs after 48h incubation induced a toxicity starting with a dosage level of 62.5 ug/cm². Below this threshold, the subsequent exposure to an alternating magnetic field (20-30 kA/m, 355 kHz) for 30 min drastically reduced the viability of the A459 cells due to the release of incorporated DOX. Our results strongly suggest that TsMLs represent a viable strategy for anticancer therapies using the magnetic field-controlled release of DOX.

Alleviating Neuroinflammation through Photothermal Conjugated Polymer Nanoparticles by Regulating Reactive Oxygen Species and Ca2+ Signaling

Neuroinflammation is one of the important manifestations of the amyloid β peptide (Aβ) protein-induced neurotoxic signaling pathway in which the aggregation of Aβ causes an increase in reactive oxygen species (ROS) and Ca²⁺ concentration. Here, near-infrared (NIR) photothermal-responsive conjugated polymer nanoparticles were designed to regulate ROS and Ca²⁺ signaling to alleviate neuroinflammation. Under 808 nm laser irradiation, the nanoparticles effectively penetrated the blood-brain barrier (BBB) and reduced the aggregation of Aβ and partially disaggregated the aggregates outside the cell, thereby reducing ROS content which downregulated the oxidative stress damage to cells. Meanwhile, the nanoparticles reduced the concentration of Ca²⁺ by inhibiting the transient receptor potential melastatin-related 2 (TRPM2) ion channel inside the cell. Ultimately, the concentration of inflammatory factor tumor necrosis factor-α was decreased. This study provides an effective strategy to reduce neuroinflammation by simultaneously regulating ROS and Ca²⁺ signaling.

Stimuli-responsive vesicles as distributed artificial organelles for bacterial activation

Intercellular communication is a hallmark of living systems. As such, engineering artificial cells that possess this behavior has been at the heart of activities in bottom-up synthetic biology. Communication between artificial and living cells has potential to confer novel capabilities to living organisms that could be exploited in biomedicine and biotechnology. However, most current approaches rely on the exchange of chemical signals that cannot be externally controlled. Here, we report two types of remote-controlled vesicle-based artificial organelles that translate physical inputs into chemical messages that lead to bacterial activation. Upon light or temperature stimulation, artificial cell membranes are activated, releasing signaling molecules that induce protein expression in Escherichia coli. This distributed approach differs from established methods for engineering stimuli-responsive bacteria. Here, artificial cells (as opposed to bacterial cells themselves) are the design unit. Having stimuli-responsive elements compartmentalized in artificial cells has potential applications in therapeutics, tissue engineering, and bioremediation. It will underpin the design of hybrid living/nonliving systems where temporal control over population interactions can be exerted.

Updates on Responsive Drug Delivery Based on Liposome Vehicles for Cancer Treatment

Liposomes are well-known nanoparticles with a non-toxic nature and the ability to incorporate both hydrophilic and hydrophobic drugs simultaneously. As modern drug delivery formulations are produced by emerging technologies, numerous advantages of liposomal drug delivery systems over conventional liposomes or free drug treatment of cancer have been reported. Recently, liposome nanocarriers have exhibited high drug loading capacity, drug protection, improved bioavailability, enhanced intercellular delivery, and better therapeutic effect because of resounding success in targeting delivery. The site targeting of smart responsive liposomes, achieved through changes in their physicochemical and morphological properties, allows for the controlled release of active compounds under certain endogenous or exogenous stimuli. In that way, the multifunctional and stimuli-responsive nanocarriers for the drug delivery of cancer therapeutics enhance the efficacy of treatment prevention and fighting over metastases, while limiting the systemic side effects on healthy tissues and organs. Since liposomes constitute promising nanocarriers for site-targeted and controlled anticancer drug release, this review focuses on the recent progress of smart liposome achievements for anticancer drug delivery applications.

Cardiolipin for Enhanced Cellular Uptake and Cytotoxicity of Thermosensitive Liposome-Encapsulated Daunorubicin toward Breast Cancer Cell Lines

Daunorubicin (DNR) and cardiolipin (CL) were co-delivered using thermosensitive liposomes (TSLs). 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1-myristoyl-2-stearoyl-sn-glycero-3-phosphocholine (MSPC), cholesterol, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] or DSPE-mPEG (2000) and CL were used in the formulation of liposomes at a molar ratio of 57:40:30:3:20, respectively. CL forms raft-like microdomains that may relocate and change lipid organization of the outer and inner mitochondrial membranes. Such transbilayer lipid movement eventually leads to membrane permeabilization. TSLs were prepared by thin-film hydration (drug:lipid ratio 1:5) where DNR was encapsulated within the aqueous core of the liposomes and CL acted as a component of the lipid bilayer. The liposomes exhibited high drug encapsulation efficiency (>90%), small size (~115 nm), narrow size distribution (polydispersity index ~0.12), and a rapid release profile under the influence of mild hyperthermia. The liposomes also exhibited ~4-fold higher cytotoxicity against MDA-MB-231 cells compared to DNR or liposomes similar to DaunoXome® (p < 0.001). This study provides a basis for developing a co-delivery system of DNR and CL encapsulated in liposomes for treatment of breast cancer.

Temperature-sensitive polymers to promote heat-triggered drug release from liposomes: Towards bypassing EPR

Heat-triggered drug release from temperature-sensitive nanocarriers upon the application of mild hyperthermia is a promising approach to achieve site-specific delivery of drugs. The combination of mild hyperthermia (41-42 °C) and temperature-sensitive liposomes (TSL) that undergo lipid phase-transition and drug release has been studied extensively and has shown promising therapeutic outcome in a variety of animal tumor models as well as initial indications of success in humans. Sensitization of liposomes to mild hyperthermia by means of exploiting the thermal behavior of temperature-sensitive polymers (TSP) provides novel opportunities. Recently, TSP-modified liposomes (TSPL) have shown potential for enhancing tumor-directed drug delivery, either by triggered drug release or by triggered cell interactions in response to heat. In this review, we describe different classes of TSPL, and analyze and discuss the mechanisms and kinetics of content release from TSPL in response to local heating. In addition, the impact of lipid composition, polymer and copolymer characteristics, serum components and PEGylation on the mechanism of content release and TSPL performance is addressed. This is done from the perspective of rationally designing TSPL, with the overall goal of conceiving efficient strategies to increase the efficacy of TSPL plus hyperthermia to improve the outcome of targeted anticancer therapy.

Synthetic Biology: Bottom-Up Assembly of Molecular Systems

The bottom-up assembly of biological and chemical components opens exciting opportunities to engineer artificial vesicular systems for applications with previously unmet requirements. The modular combination of scaffolds and functional building blocks enables the engineering of complex systems with biomimetic or new-to-nature functionalities. Inspired by the compartmentalized organization of cells and organelles, lipid or polymer vesicles are widely used as model membrane systems to investigate the translocation of solutes and the transduction of signals by membrane proteins. The bottom-up assembly and functionalization of such artificial compartments enables full control over their composition and can thus provide specifically optimized environments for synthetic biological processes. This review aims to inspire future endeavors by providing a diverse toolbox of molecular modules, engineering methodologies, and different approaches to assemble artificial vesicular systems. Important technical and practical aspects are addressed and selected applications are presented, highlighting particular achievements and limitations of the bottom-up approach. Complementing the cutting-edge technological achievements, fundamental aspects are also discussed to cater to the inherently diverse background of the target audience, which results from the interdisciplinary nature of synthetic biology. The engineering of proteins as functional modules and the use of lipids and block copolymers as scaffold modules for the assembly of functionalized vesicular systems are explored in detail. Particular emphasis is placed on ensuring the controlled assembly of these components into increasingly complex vesicular systems. Finally, all descriptions are presented in the greater context of engineering valuable synthetic biological systems for applications in biocatalysis, biosensing, bioremediation, or targeted drug delivery.

Physically stimulus-responsive nanoparticles for therapy and diagnosis

Nanoparticles offer numerous advantages in various fields of science, particularly in medicine. Over recent years, the use of nanoparticles in disease diagnosis and treatments has increased dramatically by the development of stimuli-responsive nano-systems, which can respond to internal or external stimuli. In the last 10 years, many preclinical studies were performed on physically triggered nano-systems to develop and optimize stable, precise, and selective therapeutic or diagnostic agents. In this regard, the systems must meet the requirements of efficacy, toxicity, pharmacokinetics, and safety before clinical investigation. Several undesired aspects need to be addressed to successfully translate these physical stimuli-responsive nano-systems, as biomaterials, into clinical practice. These have to be commonly taken into account when developing physically triggered systems; thus, also applicable for nano-systems based on nanomaterials. This review focuses on physically triggered nano-systems (PTNSs), with diagnostic or therapeutic and theranostic applications. Several types of physically triggered nano-systems based on polymeric micelles and hydrogels, mesoporous silica, and magnets are reviewed and discussed in various aspects.

Near-Infrared Light-Responsive Nanoinhibitors for Tumor Suppression through Targeting and Regulating Anion Channels

The gated state of anion channels is involved in the regulation of proliferation and migration of tumors. Specific regulators are urgently needed for efficacious cancer ablation. For this purpose, it is essential to understand the molecular mechanisms of interaction between the regulators and anion channels and apply this knowledge to regulate anion channels. Transmembrane 16A (TMEM16A) is the molecular basis of the calcium-activated chloride channels. It is an anion channel activated by Ca²⁺, and the inhibition of TMEM16A is associated with a decrease in tumorigenesis. Herein, we characterized a natural compound procyanidin (PC) as an efficacious and selective inhibitor of TMEM16A with an IC₅₀ of 10.6 ± 0.6 μM. Our research revealed the precise sites (D383, R535, and E624) of electrostatic interactions between PC and TMEM16A. Near-infrared (NIR)-light-responsive photothermal conjugated polymer nanoparticles encapsulating PC (CPNs-PC) were established to remotely target and regulate the TMEM16A anion channel. Upon NIR irradiation, CPNs-PC downregulated the signaling pathway downstream of TMEM16A and arrested the cell cycle progression of cancer cells and improved the bioavailability of PC. The tumor inhibition ratio of CPNs-PC was superior to PC by 13.4%. Our findings enabled the development of a strategy to accurately and remotely regulate anion channels to promote tumor regression using NIR-light-responsive conjugated polymer nanoparticles containing specific inhibitors of TMEM16A.

Lipid nano-vesicles for thyroid hormone encapsulation: A comparison between different fabrication technologies, drug loading, and an in vitro delivery to human tendon stem/progenitor cells in 2D and 3D culture

Phosphatidylcholine (PC) vesicles loaded with Triiodothyronine (T3) were fabricated using different manufacturing methods: thin layer hydration plus sonication (TF-UF), supercritical liposome formation (SC), and microfluidic technology (MF). Vesicles obtained by MF had the lowest mean diameter (88.61 ± 44.48 nm) with a Zeta Potential of -20.1 ± 5.90 mV and loading of 10 mg/g (encapsulation efficiency: 57%). In contrast, SC vesicles showed extremely low encapsulation efficiency (<10%) probably due to T3 solubility in ethanol/carbon dioxide mixture; despite TF-UF vesicles exhibiting good size (167.7 ± 90 nm; Zp -8.50 ± 0.60 mV) and loading (10 mg/g), poor mass recovery was obtained (50% loss). MF vesicles had low cytotoxicity, and they were well enough internalized by both HeLa and human tendon stem/progenitor cells (hTSPCs). Their biological activity was also monitored in both 2D and 3D cultures of hTSPCs supplemented with therapeutical concentrations of PC/T3 nano-liposomes. 2D culture showed almost similar constitutive gene expression compared to control culture supplemented with free-T3. On the contrary, when hTPSCs 3D culture was assembled, it showed a more evident homogeneous distribution of FITC labeled vesicles within the high-density structure and a significant upregulation of cell constitutive genes, such as type I Collagen (4.8-fold; p < 0.0001) at day 7, compared to the control, suggesting that T3/PC formulation has increased T3 cytosolic concentration, thus improving cells metabolic activity. The study supported MF technology for nano-carriers fabrication and opens perspectives on the activity of PC/T3 nano-vesicles as innovative formulations for TPSCs stimulation in ECM secretion.

Thermo-sensitive self-assembly of poly(ethylene imine)/(phenylthio) acetic acid ion pair in surfactant solutions

Poly(ethylene imine)/(phenylthio) acetic acid (PEI/PTA) ion pairs exhibited an upper critical solution temperature (UCST) behavior in an aqueous solution and the UCST was higher as the PTA content was more. The UCST of the ion pair decreased with increasing Brij S100 (BS 100, a nonionic surfactant) concentration but increased with increasing cetylpridinium chloride (CPC, a cationic surfactant) and sodium lauroylsarcosinate (SLS, an anionic surfactant) concentration. TEM microscopy demonstrated BS 100 markedly reduced the size of PEI/PTA ion pair self-assembly (IPSAM) whereas CPC and SLS had little effect on the size and the integrity of IPSAM. ¹H NMR spectroscopy showed the hydrophobic interaction among the phenyl groups of PEI/PTA ion pairs took place. It also demonstrated the hydrophobic interaction between BS 100 and PTA and the electrostatic interaction between CPC and PTA and between SLS and PEI occurred. X-ray photoelectron spectroscopy disclosed the PTA of PEI/PTA IPSAM could be readily oxidized by H₂O₂ even at a low concentration (e.g. 0.005%). IPSAM released its payload (i.e. nile red) in a temperature and oxidation-responsive manner. The surfactants (i.e. BS 100, CPC, and SLS) suppressed the thermally triggered release in a different way. The effectiveness of the surfactant to suppress the release was in the order of BS 100 > CPC > SLS. IPSAM released its content more extensively as H₂O₂ (an oxidizing agent) concentration was higher. The ionic surfactants (i.e. CPS and SLS) had little effect on the oxidation-induced release degree but the nonionic surfactant (BS 100) markedly suppressed the release degree.

Vesicular and Planar Membranes of Archaea Lipids: Unusual Physical Properties and Biomedical Applications

Liposomes and planar membranes made of archaea or archaea-like lipids exhibit many unusual physical properties compared to model membranes composed of conventional diester lipids. Here, we review several recent findings in this research area, which include (1) thermosensitive archaeosomes with the capability to drastically change the membrane surface charge, (2) MthK channel's capability to insert into tightly packed tetraether black lipid membranes and exhibit channel activity with surprisingly high calcium sensitivity, and (3) the intercalation of apolar squalane into the midplane space of diether bilayers to impede proton permeation. We also review the usage of tetraether archaeosomes as nanocarriers of therapeutics and vaccine adjuvants, as well as the biomedical applications of planar archaea lipid membranes. The discussion on archaeosomal therapeutics is focused on partially purified tetraether lipid fractions such as the polar lipid fraction E (PLFE) and glyceryl caldityl tetraether (GCTE), which are the main components of PLFE with the sugar and phosphate removed.

Materials and device design for advanced phototherapy systems

Phototherapy has recently emerged as a promising solution for cancer treatment due to its multifunctionality and minimal invasiveness. Notwithstanding the limited penetration depth of light through skin, the ability of photopharmaceutical device systems to deliver light to desired lesions is important. The device system deploys advanced biocompatible materials and fabrication technologies for electronics, and eventually enables more efficient phototherapy. In this review, we focus on diverse optical electronics to illuminate the lesion site with light. Then, moving on to the phototherapy, we highlight photo-thermal therapy with light absorbing materials, photo-activated chemotherapy with light sensitive materials, and photo-dynamic therapy using photosensitizers. Furthermore, we introduce a drug delivery system that can deliver these photopharmaceutical agents spatiotemporally to the tumor site. To this end, we provide a general overview of materials and devices for phototherapy and discuss critical issues and pending limitations of such phototherapy.

Doxorubicin-encapsulated thermosensitive liposome-functionalized photothermal composite scaffolds for synergistic photothermal therapy and chemotherapy

Synergistic therapy, especially the combination of photothermal therapy and chemotherapy, has been proposed as an effective therapeutic approach for breast cancer treatment. In this study, a smart platform for synergistic photothermal therapy and chemotherapy was developed by hybridizing doxorubicin-encapsulated thermosensitive liposomes and gold nanorods into porous scaffolds of gelatin and polyglutamic acid (Dox-lipo/AuNR/Gel/PGA). The Dox-lipo/AuNR/Gel/PGA composite scaffolds had good photothermal conversion and temperature-dependent doxorubicin release properties. Under near-infrared laser irradiation, the composite scaffolds increased the local temperature to not only kill the breast cancer cells in the scaffolds but also accelerate the release of doxorubicin to eliminate the breast cancer cells surrounding the scaffolds. In vitro cell culture and in vivo mouse experiments demonstrated that the synergistic effects of photothermal ablation combined with doxorubicin-induced inhibition of the breast cancer cells in and surrounding the composite scaffolds under near-infrared laser irradiation. Moreover, after drug release was complete, the composite scaffolds fostered human bone marrow-derived mesenchymal stem cell proliferation. These results suggested that the composite scaffolds provided synergistic photothermal therapy and chemotherapy for breast cancer cell elimination at the early stage and promoted stem cell activities at the late stage. Therefore, this composite scaffold holds great potential as a synergistic therapy platform for breast cancer treatment.

NIR-Mediated drug release and tumor theranostics using melanin-loaded liposomes

BACKGROUND

Heat generation in a drug delivery carrier by exposure to near-infrared (NIR) light with excellent tissue transmittance is an effective strategy for drug release and tumor therapy. Because liposomes have amphiphilic properties, they are useful as drug carriers. Liposomes are also very suitable for drug delivery strategies using heat generation by NIR laser because lipid bilayers are easily broken by heat. Thermally generated bubbles from liposomes not only induce drug release, but also enable ultrasound imaging.

METHODS

Melanin, perfluorohexane (PFH), and 5-fluorouracil (5-FU)-loaded liposomes (melanin@PFH@5-FU-liposomes) that can generate heat and bubble by NIR laser irradiation were prepared by a thin film method. Conversion of light to heat and bubble generation of melanin@PFH@5-FU-liposomes were evaluated using an infrared (IR) thermal imaging camera and an ultrasound imaging system both in vitro and in vivo. To investigate tumor therapeutic effect, NIR laser of 808 nm was used to irradiate tumor site for 10 min after injecting melanin@PFH@5-FU-liposome into tail veins of CT26-bearing mice.

RESULTS

Melanin@PFH@5-FU-liposomes showed a spherical shape with a size of 209.6 ± 4.3 nm. Upon NIR laser irradiation, melanin@PFH@5-FU-liposomes exhibited effective temperature increase both in vitro and in vivo. In this regard, temperature increase caused a phase transition of PFH to induce bubble generation dramatically, resulting in effective drug release behavior and ultrasound imaging. The temperature of the tumor site was increased to 52 t and contrast was greatly enhanced during ultrasound imaging due to the generation of bubble. More importantly, tumor growth was effectively inhibited by injection of melanin@PFH@5-FU-liposomes with laser irradiation.

CONCLUSIONS

Based on intrinsic photothermal properties of melanin and phase transition properties of PFH, melanin@PFH@5-FU-liposomes exhibited effective heat and bubble generation upon NIR laser irradiation. The elevated temperature induced bubble generation, resulting in contrast enhancement of ultrasound imaging. Melanin@PFH@5-FU-liposomes under NIR laser irradiation induced the death of cancer cells, thereby effectively inhibiting tumor growth. These results suggest that melanin@PFH@5-FU-liposomes can be utilized as a promising agent for photothermal tumor therapy and ultrasound imaging.

Sequential Dual Delivery System Based on siCOX-2-Loaded Gold Nanostar and Thermal-Sensitive Liposomes Overcome Hypoxia-Mediated Multidrug Resistance in Tumors

Reversing hypoxia-mediated multidrug resistance (MDR) presents a unique challenge in clinical chemotherapy. Here, a sequential dual delivery system composited with Cyclooxygenase-2 siRNA (siCOX-2) in poly-d-arginine (9R)/2-deoxyglucose (DG)-loaded gold nanostar (GNS) (siCOX-2@RDG) and paclitaxel (PTX)-loaded thermosensitive liposome (PTSL) was proposed to conquer the hypoxia-mediated MDR in tumors. As a result, the prepared siCOX-2@RDG exhibited a starlike morphology with a uniform particle size of 194.36 ± 1.44 nm and a ζ-potential of -11.83 ± 2.01 mV. In vitro, PTSL displayed expected thermal-responsive release properties. As expected, siCOX-2@RDG displayed exceptional DG-mediated hypoxia-targeting capability both in vitro and in vivo and downregulated the expression of COX-2 successfully. Meanwhile, GNS-triggered hyperthermia elevated the cellular uptake of PTSL in PTX-resistant HepG2(HepG2/PTX) cells in vitro and enhanced the permeability of tumor tissues, thus elevating the valid retention of PTX into solid tumors. Finally, we demonstrated that the sequential dual systems composed of siCOX-2@RDG and PTSL could reverse hypoxia-mediated MDR and exhibit excellent synergistic antitumor effects both in vitro and in vivo, prolonging the survival of tumor-bearing mice. The devised sequential dual systems, composed of two independent nanosystems, have a promising potential to overcome hypoxia-mediated MDR in clinical practice.

Iron oxide nanoflowers encapsulated in thermosensitive fluorescent liposomes for hyperthermia treatment of lung adenocarcinoma

Magnetic hyperthermia (MHT) is in the spotlight of nanomedical research for the treatment of cancer employing magnetic iron oxide nanoparticles and their intrinsic capability for heat dissipation under an alternating magnetic field (AMF). Herein we focus on the synthesis of iron oxide nanoflowers (Nfs) of different sizes (15 and 35 nm) and coatings (bare, citrate, and Rhodamine B) while comparing their physicochemical and magnetothermal properties. We encapsulated colloidally stable citrate coated Nfs, of both sizes, in thermosensitive liposomes via extrusion, and RhB was loaded in the lipid bilayer. All formulations proved hemocompatible and cytocompatible. We found that 35 nm Nfs, at lower concentrations than 15 nm Nfs, served better as nanoheaters for magnetic hyperthermia applications. In vitro, magnetic hyperthermia results showed promising therapeutic and imaging potential for RhB loaded magnetoliposomes containing 35 nm Nfs against LLC and CULA cell lines of lung adenocarcinoma.

Liposomes: structure, composition, types, and clinical applications

Liposomes are now considered the most commonly used nanocarriers for various potentially active hydrophobic and hydrophilic molecules due to their high biocompatibility, biodegradability, and low immunogenicity. Liposomes also proved to enhance drug solubility and controlled distribution, as well as their capacity for surface modifications for targeted, prolonged, and sustained release. Based on the composition, liposomes can be considered to have evolved from conventional, long-circulating, targeted, and immune-liposomes to stimuli-responsive and actively targeted liposomes. Many liposomal-based drug delivery systems are currently clinically approved to treat several diseases, such as cancer, fungal and viral infections; more liposomes have reached advanced phases in clinical trials. This review describes liposomes structure, composition, preparation methods, and clinical applications.