Trends and developments in liposome drug delivery systems

Overcoming resistance: Chitosan-modified liposomes as targeted drug carriers in the fight against multidrug resistant bacteria-a review

Antimicrobial resistance (AMR) poses a significant global health threat, rendering standard antibiotics ineffective against multi-drug resistant bacteria. To tackle this urgent issue, innovative approaches are essential. Liposomes, small spherical vesicles made of a phospholipid bilayer, present a promising solution. These vesicles can encapsulate various medicines and are both biocompatible and biodegradable. Their ability to be modified for targeted tissue or cell uptake makes them an ideal drug delivery system. By delivering antibiotics directly to infection sites, liposomes minimize side effects and reduce the development of resistance. However, challenges such as poor stability and rapid drug leakage limit their biological application. Chitosan, a biocompatible polymer, enhances liposome interaction with specific tissues or cells, enabling selective drug release at infection sites. Incorporating chitosan into liposome formulations alters and diversifies their surface characteristics through electrostatic interactions, resulting in improved stability and pH-sensitive drug release. These interactions are crucial for enhancing drug retention and targeted delivery, especially in varying pH environments like tumor sites or infection areas, thereby improving therapeutic outcomes and reducing systemic side effects. This review discusses recent advancements, challenges, and the need for further research to optimize liposome formulations and enhance targeted drug delivery for effective AMR treatment. Chitosan-modified liposomes offer a promising strategy to overcome AMR and improve antimicrobial therapies.

Lipid-Based Catalysis Demonstrated by Bilayer-Enabled Ester Hydrolysis

Lipids have not traditionally been considered likely candidates for catalyzing reactions in biological systems. However, there is significant evidence that aggregates of amphiphilic compounds are capable of catalyzing reactions in synthetic organic chemistry. Here, we demonstrate the potential for the hydrophobic region of a lipid bilayer to provide an environment suitable for catalysis by means of a lipid aggregate capable of speeding up a chemical reaction. By bringing organic molecules into the nonpolar or hydrophobic region of a lipid bilayer, reactions can be catalyzed by individual or collections of small, nonpolar, or amphiphilic molecules. We demonstrate this concept by the ester hydrolysis of calcein-AM to produce a fluorescent product, which is a widely used assay for esterase activity in cells. The reaction was first carried out in a two-phase octanol-water system, with the organic phase containing the cationic amphiphiles cetyltrimethylammonium bromide (CTAB) or octadecylamine. The octanol phase was then replaced with phospholipid vesicles in water, where the reaction was also found to be carried out. The reaction was monitored using quantitative fluorescence, which revealed catalytic turnover numbers on a scale of 10-7 to 10-8 s-1 for each system, which is much slower than enzymatic catalysis. The reaction product was characterized by 1H-NMR measurements, which were consistent with ester hydrolysis. The implications of thinking about lipids and lipid aggregates as catalytic entities are discussed in the context of biochemistry, pharmacology, and synthetic biology.

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.

Novel Drug Delivery Systems: An Important Direction for Drug Innovation Research and Development

The escalating demand for enhanced therapeutic efficacy and reduced adverse effects in the pharmaceutical domain has catalyzed a new frontier of innovation and research in the field of pharmacy: novel drug delivery systems. These systems are designed to address the limitations of conventional drug administration, such as abbreviated half-life, inadequate targeting, low solubility, and bioavailability. As the disciplines of pharmacy, materials science, and biomedicine continue to advance and converge, the development of efficient and safe drug delivery systems, including biopharmaceutical formulations, has garnered significant attention both domestically and internationally. This article presents an overview of the latest advancements in drug delivery systems, categorized into four primary areas: carrier-based and coupling-based targeted drug delivery systems, intelligent drug delivery systems, and drug delivery devices, based on their main objectives and methodologies. Additionally, it critically analyzes the technological bottlenecks, current research challenges, and future trends in the application of novel drug delivery systems.

Evaluation of the antifungal properties of nanoliposomes containing rhinacanthin-C isolated from the leaves of Rhinacanthus nasutus

Fungal infections represent a challenging threat to the human health. Microsporum gypseum and Trichophyton rubrum are pathogenic fungi causing various topical mycoses in humans. The globally emerging issue of resistance to fungi demands the development of novel therapeutic strategies. In this context, the application of nanoliposomes as vehicles for carrying active therapeutic agents can be a suitable alternative. In this study, rhinacanthin-C was isolated from Rhinacanthus naustus and encapsulated in nano-liposomal formulations, which were prepared by the modified ethanol injection method. The two best formulations composed of soybean phosphatidylcholine (SPC), cholesterol (CHL), and tween 80 (T80) in a molar ratio of 1:1:0 (F1) and 1:1:0.5 (F2) were proceeded for experimentation. The physical characteristics and antifungal activities were performed and compared with solutions of rhinacanthin-C. The rhinacanthin-C encapsulating efficiencies in F1 and F2 were 94.69 ± 1.20% and 84.94 ± 1.32%, respectively. The particle sizes were found to be about 221.4 ± 13.76 nm (F1) and 115.8 ± 23.33 nm (F2), and zeta potential values of -38.16 mV (F1) and -40.98 mV (F2). Similarly, the stability studies of rhinacanthin-C in liposomes demonstrated that rhinacanthin-C in both formulations was more stable in mediums with pH of 4.0 and 6.6 than pure rhinacanthin-C when stored at the same conditions. Rhinacanthin-C in F1 was slightly more stable than F2 when stored in mediums with a pH of 10.0 after three months of storage. However, rhinacanthin-C in both formulations was less stable than pure rhinacanthin-C in a basic medium of pH 10.0. The antifungal potential was evaluated against M. gypsum and T. rubrum. The findings revealed a comparatively higher zone of inhibition for F1. In the MIC study, SPC: CHL: T80 showed higher inhibition against M. gypseum and a slightly higher inhibition against T. rubrum compared to free rhinacanthin-C solution. Moreover, rhinacanthin-C showed significant interaction against 14α-demethylase in in silico study. Overall, this study demonstrates that nanoliposomes containing rhinacanthin-C can improve the stability and antifungal potential of rhinacanthin-C with sustained and prolonged duration of action and could be a promising vehicle for delivery of active ingredients for targeting various fungal infections.

Ultrasound robotics for precision therapy

In recent years, the application of microrobots in precision therapy has gained significant attention. The small size and maneuverability of these micromachines enable them to potentially access regions that are difficult to reach using traditional methods; thus, reducing off-target toxicities and maximizing treatment effectiveness. Specifically, acoustic actuation has emerged as a promising method to exert control. By harnessing the power of acoustic energy, these small machines potentially navigate the body, assemble at the desired sites, and deliver therapies with enhanced precision and effectiveness. Amidst the enthusiasm surrounding these miniature agents, their translation to clinical environments has proven difficult. The primary objectives of this review are threefold: firstly, to offer an overview of the fundamental acoustic principles employed in the field of microrobots; secondly, to assess their current applications in medical therapies, encompassing tissue targeting, drug delivery or even cell infiltration; and lastly, to delve into the continuous efforts aimed at integrating acoustic microrobots into in vivo applications.

Ultrasound assisted extraction and liposome encapsulation of olive leaves and orange peels: How to transform biomass waste into valuable resources with antimicrobial activity

Every year million tons of by-products and waste from olive and orange processing are produced by agri-food industries, thus triggering environmental and economic problems worldwide. From the perspective of a circular economy model, olive leaves and orange peels can be valorized in valuable products due to the presence of bioactive compounds such as polyphenols exhibiting beneficial effects on human health. The aqueous extracts of olive leaves and orange peels rich in phenolic compounds were prepared by ultrasound-assisted extraction. Both extracts were characterized in terms of yield of extraction, total phenolic content and antioxidant capacity; the polyphenolic profiles were deeper investigated by HPLC-MS analysis. Each extract was included in liposomes composed by a natural phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine,and cholesterol prepared according to the thin-layer evaporation method coupled with a sonication process. The antimicrobial activity of the extracts, free and loaded in liposomes, was investigated according to the broth macrodilution method against different strains of potential bacterial pathogenic species: Staphylococcus aureus (NCIMB 9518), Bacillus subtilis (ATCC 6051) and Enterococcus faecalis (NCIMB 775) as Gram-positive, while Escherichia coli (NCIMB 13302), Pseudomonas aeruginosa (NCIMB 9904) and Klebsiella oxytoca (NCIMB 12259) as Gram-negative. The encapsulation of olive leaves extract in liposomes enhanced its antibacterial activity against S. aureus by an order of magnitude.

Nose-to-brain drug delivery for the treatment of glioblastoma multiforme: nanotechnological interventions

Glioblastoma multiforme (GBM) is the most aggressive malignant brain tumor with a short survival rate. Extensive research is underway for the last two decades to find an effective treatment for GBM but the tortuous pathophysiology, development of chemoresistance, and presence of BBB are the major challenges, prompting scientists to look for alternative targets and delivery strategies. Therefore, the nose to brain delivery emerged as an unorthodox and non-invasive route, which delivers the drug directly to the brain via the olfactory and trigeminal pathways and also bypasses the BBB and hepatic metabolism of the drug. However, mucociliary clearance, low administration volume, and less permeability of nasal mucosa are the obstacles retrenching the brain drug concentration. Thus, nanocarrier delivery through this route may conquer these limitations because of their unique surface characteristics and smaller size. In this review, we have emphasized the advantages and limitations of nanocarrier technologies such as polymeric, lipidic, inorganic, and miscellaneous nanoparticles used for nose-to-brain drug delivery against GBM in the past 10 years. Furthermore, recent advances, patents, and clinical trials are highlighted. However, most of these studies are in the early stages, so translating their outcomes into a marketed formulation would be a milestone in the better progression and survival of glioma patients.

In vitro co-delivery of 5-fluorouracil and all-trans retinoic acid by PEGylated liposomes for colorectal cancer treatment

BACKGROUND

Single-target inhibitors have not been successful in cancer treatment due to the development of drug resistance. Nevertheless, therapeutic agents capable of simultaneously inhibiting multiple targets have revealed encouraging results in inducing apoptosis and overcoming drug resistance in cancerous cells. Here, we designed a composite liposomal nano-carrier co-loading 5-Fluorouracil (5-FU) with all-trans retinoic acid (ATRA) to assess anticancer efficacy of the combined drugs in colorectal cancer (CRC).

METHODS

A PEGylated liposomal nano-carrier with phospholipid/cholesterol/DSPE-PEG (2000) was synthesized by the thin film hydration technique for co-delivery of ATRA and 5-FU. After characterizing, the role of 5-FU and ATRA co-loaded liposomal nano-carrier in proliferation, epithelial-mesenchymal transition (EMT), apoptosis, and cancer stem cells (CSCs) were investigated by using colony forming and MTT assay, RT-qPCR and Annexin V/PI kit.

RESULTS

The average size of liposomes (LPs) was < 150 nm with uniform size distribution. Drug release analyses indicated that both ATRA and 5-FU could simultaneously release from LPs in a sustained release manner. The synergistic inhibitory effects of ATRA and 5-FU loaded in LPs were verified with a combination index of 0.43. Dual drug LPs showed the highest cytotoxicity, enhanced inhibition of cell proliferation, increased apoptotic potential, decreased CSCs, and attenuated EMT-associated biomarkers. Also, dual drug LPs decreased β-catenin gene expression more than other liposomal formulations.

CONCLUSION

These findings suggest that using LPs to achieve a synergistic effect of ATRA and 5-FU is an effectual approach to increase the therapeutic effect of 5-FU toward CRC cells.

Selected strategies to fight pathogenic bacteria

Natural products and analogues are a source of antibacterial drug discovery. Considering drug resistance levels emerging for antibiotics, identification of bacterial metalloenzymes and the synthesis of selective inhibitors are interesting for antibacterial agent development. Peptide nucleic acids are attractive antisense and antigene agents representing a novel strategy to target pathogens due to their unique mechanism of action. Antisense inhibition and development of antisense peptide nucleic acids is a new approach to antibacterial agents. Due to the increased resistance of biofilms to antibiotics, alternative therapeutic options are necessary. To develop antimicrobial strategies, optimised in vitro and in vivo models are needed. In vivo models to study biofilm-related respiratory infections, device-related infections: ventilator-associated pneumonia, tissue-related infections: chronic infection models based on alginate or agar beads, methods to battle biofilm-related infections are discussed. Drug delivery in case of antibacterials often is a serious issue therefore this review includes overview of drug delivery nanosystems.

Advanced application of nanotechnology in active constituents of Traditional Chinese Medicines

Traditional Chinese Medicines (TCMs) have been used for centuries for the treatment and management of various diseases. However, their effective delivery to targeted sites may be a major challenge due to their poor water solubility, low bioavailability, and potential toxicity. Nanocarriers, such as liposomes, polymeric nanoparticles, inorganic nanoparticles and organic/inorganic nanohybrids based on active constituents from TCMs have been extensively studied as a promising strategy to improve the delivery of active constituents from TCMs to achieve a higher therapeutic effect with fewer side effects compared to conventional formulations. This review summarizes the recent advances in nanocarrier-based delivery systems for various types of active constituents of TCMs, including terpenoids, polyphenols, alkaloids, flavonoids, and quinones, from different natural sources. This review covers the design and preparation of nanocarriers, their characterization, and in vitro/vivo evaluations. Additionally, this review highlights the challenges and opportunities in the field and suggests future directions for research. Nanocarrier-based delivery systems have shown great potential in improving the therapeutic efficacy of TCMs, and this review may serve as a comprehensive resource to researchers in this field.

Nanoliposomal Coencapsulation of Dorema aucheri Extract and Curcumin; Enhanced Cytotoxicity, Apoptosis Induction, and Inhibition of EGFR Gene Expression in Oral Cancer Cells OCC-02

Curcumin is one of the natural anticancer drugs but its efficiency is limited by low stability, insufficient bioavailability, poor solubility, and poor permeability. Dorema aucheri (Bilhar) is a herb with precious pharmaceutical properties. This study aimed to develop a nanoliposome-based curcumin and Bilhar extract codelivery system. The nanocompounds were synthesized using the lipid thin-film hydration method and characterized by transmission electron microscopy, and dynamic light scattering techniques, and their cytotoxicity and apoptotic effect on the primary oral cancer cell line were evaluated via 2,5-diphenyl-2H-tetrazolium bromide assay and flow cytometry. Moreover, the expression of the epidermal growth factor receptor (EGFR) gene in the treated cells was assessed using the real-time polymerase chain reaction technique. Based on the results, nanoliposomes had a size of 91 ± 10 nm with a polydispersity index of 0.13. Free curcumin, the extract, and the curcumin-extract combination showed dose-dependent toxicity against cancer cells; yet, the extract (IC50: 86 µg/ml) and curcumin-extract (IC50: 65 µg/ml) activities were much more than curcumin (IC50: 121 µg/ml). Also, the curcumin and extract loaded on liposomes showed a dose and time-dependent cytotoxicity. After loading the curcumin-extract compound on nanoliposomes, their IC50 decreased from 180 µg/ml (within 24 hr) to 43 µg/ml (within 72 hr), indicating their sustainable release and activity. Likewise, this compound induced the highest apoptosis percentage (95%) in cancerous cells and inhibited the expression of the EGFR gene in the cells by 81% ± 3%. These findings demonstrated the effectiveness of the Bilhar extract against oral cancer cells. Also, in combination with curcumin, it showed an additive activity that considerably improved after loading on nanoliposomes.

Preparation of nano-sized multi-vesicular vesicles (MVVs) and its application in co-delivery of doxorubicin and curcumin

Multi-vesicular vesicles (MVVs) offer structural advantages in terms of drug encapsulation and physiological stability. In this study, we address the challenge of preparing small-sized MVVs for drug delivery. The nano-sized MVVs (∼120 nm) loaded with doxorubicin (DOX) and curcumin (CUR) (DOX/CUR@MVVs) were successfully prepared using a glass bead combined with a thin film dispersion method. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis confirmed the independent non-homocentric vesicle structures of DOX/CUR@MVVs with homogeneous particle sizes. The experimental results showed high encapsulation rates of DOX and CUR in DOX/CUR@MVVs, reaching 82.5 ± 0.75 % and 85.9 ± 0.69 %, respectively. Moreover, the MVVs exhibited good biosafety and sustained release properties. Notably, the bioavailability of DOX and CUR in DOX/CUR@MVVs was enhanced compared to free DOX and CUR, with increases of 4.2 and 2.1 times, respectively. And the half-life of DOX and CUR was extended by 10 times in DOX/CUR@MVVs. In vivo antitumor experiments demonstrated that nano-sized DOX/CUR@MVVs significantly improved the antitumor activity while reducing the toxic side effects of DOX. Overall, the successful preparation of nano-sized DOX/CUR@MVVs and their potent and low-toxic antitumor effects provide a critical experimental reference for the combined antitumor therapy of MVVs and liposomes.

Encapsulation of Ru(II) Polypyridine Complexes for Tumor-Targeted Anticancer Therapy

Ru(II) polypyridine complexes have attracted much attention as anticancer agents because of their unique photophysical, photochemical, and biological properties. Despite their promising therapeutic profile, the vast majority of compounds are associated with poor water solubility and poor cancer selectivity. Among the different strategies employed to overcome these pharmacological limitations, many research efforts have been devoted to the physical or covalent encapsulation of the Ru(II) polypyridine complexes into nanoparticles. This article highlights recent developments in the design, preparation, and physicochemical properties of Ru(II) polypyridine complex-loaded nanoparticles for their potential application in anticancer therapy.

Perspectives on cutting-edge nanoparticulate drug delivery technologies based on lipids and their applications

Numerous nanotech arenas in therapeutic biology have recently provided a scientific platform to manufacture a considerable swath of unique chemical entities focusing on drugs. Recently, nanoparticulate drug delivery systems have emerged to deliver a specific drug to a specified site. Among all other carriers, lipids possess features exclusive to nanostructured dosage forms. The bioavailability of orally administered drugs is typically negatively affected by their poor water solubility, resulting from the unique chemical moieties introduced. Because of their unique advantages, lipid nanoparticles must become increasingly predictable as a robust delivery mechanism. The enhanced biopharmaceutical properties and significance of lipid-based targeting technologies such as liposomes, niosomes, solid lipid nanoparticles and micelles are highlighted in this review. Pharmaceutical implications of lipid nanocarriers for the transport and distribution of various therapeutic agents, such as biotechnological products and small pharmaceutical molecules, is a booming topic. Lipid nanoparticles as drug delivery systems have many appealing properties, including high biocompatibility, ease of preparation, tissue specificity, avoidance of reticuloendothelial systems, delayed drug release, scale-up feasibility, nontoxicity and targeted delivery. The use of lipid nanoparticles to enhance the transport of biopharmaceuticals is currently considered state-of-the-art. Similarly, we critically examine the upcoming guidelines that therapeutic scientists should handle.

Advances of liposomal mediated nanocarriers for the treatment of dermatophyte infections

Due to the adverse effects associated with long-term administration of antifungal drugs used for treating dermatophytic lesions like tinea unguium, there is a critical need for novel antifungal therapies that exhibit improved absorption and minimal adverse effects. Nanoformulations offer a promising solution in this regard. Topical formulations may penetrate the upper layers of the skin, such as the stratum corneum, and release an appropriate amount of drugs in therapeutic quantities. Liposomes, particularly nanosized ones, used as topical medication delivery systems for the skin, may have various roles depending on their size, lipid and cholesterol content, ingredient percentage, lamellarity, and surface charge. Liposomes can enhance permeability through the stratum corneum, minimize systemic effects due to their localizing properties, and overcome various challenges in cutaneous drug delivery. Antifungal medications encapsulated in liposomes, including fluconazole, ketoconazole, croconazole, econazole, terbinafine hydrochloride, tolnaftate, and miconazole, have demonstrated improved skin penetration and localization. This review discusses the traditional treatment of dermatophytes and liposomal formulations. Additionally, promising liposomal formulations that may soon be available in the market are introduced. The objective of this review is to provide a comprehensive understanding of dermatophyte infections and the role of liposomes in enhancing treatment.

Review of the Role of Nanotechnology in Overcoming the Challenges Faced in Oral Cancer Diagnosis and Treatment

Throughout the world, oral cancer is a common and aggressive malignancy with a high risk of morbidity, mortality, and recurrence. The importance of early detection in cancer prevention and disease treatment cannot be overstated. Conventional therapeutic strategies have minor difficulties but considerable side effects and unfavourable consequences in clinical applications. Hence, there is a requirement for effective ways for early detection and treatment of oral cancer. At present, numerous forms of nanoparticles have piqued researchers' interest as a potentially useful tool for diagnostic probes and medicinal devices. Because of their inherent physicochemical properties and customizable surface modification, they are able to circumvent some of restrictions and accomplish the intended diagnostic and therapeutic impact. Nanotechnology is a unique field that has revolutionised the industry and is paving the way for new treatments for oral cancer. It can help with a better diagnosis with less harmful substances and is setting current guidelines for treatment. The use of nanotechnology in cancer diagnosis, therapy, and care improves clinical practise dramatically. The different types of nanoparticles that have been developed for the diagnosis and therapy of oral cancers will be covered in this study. The difficulties and potential uses of nanoparticles in the treatment and diagnosis of oral cancer are then highlighted. In order to emphasise existing difficulties and potential remedies for oral cancer, a prospective view of the future is also provided.

Advances in anti-invasive fungal drug delivery systems

Currently, the first-line drugs for invasive fungal infections (IFI), such as amphotericin B, fluconazole and itraconazole, have drawbacks including poor water solubility, low bioavailability, and severe side effects. Using drug delivery systems is a promising strategy to improve the efficacy and safety of traditional antifungal therapy. Synthetic and biomimetic carriers have greatly facilitated the development of targeted delivery systems for antifungal drugs. Synthetic carrier drug delivery systems, such as liposomes, nanoparticles, polymer micelles, and microspheres, can improve the physicochemical properties of antifungal drugs, prolong their circulation time, enhance targeting capabilities, and reduce toxic side effects. Cell membrane biomimetic drug delivery systems, such as macrophage or red blood cell membrane-coated drug delivery systems, retain the membrane structure of somatic cells and confer various biological functions and specific targeting abilities to the loaded antifungal drugs, exhibiting better biocompatibility and lower toxicity. This article reviews the development of antifungal drug delivery systems and their application in the treatment of IFI, and also discusses the prospects of novel biomimetic carriers in antifungal drug delivery.

PEGylated Lipid Nanoparticle Formulations: Immunological Safety and Efficiency Perspective

Lipid nanoparticles (LNPs) have been recognized as efficient vehicles to transport a large variety of therapeutics. Currently in the spotlight as important constituents of the COVID-19 mRNA vaccines, LNPs play a significant role in protecting and transporting mRNA to cells. As one of their key constituents, polyethylene glycol (PEG)-lipid conjugates are important in defining LNP physicochemical characteristics and biological activity. PEGylation has proven particularly efficient in conferring longer systemic circulation of LNPs, thus greatly improving their pharmacokinetics and efficiency. Along with revealing the benefits of PEG conjugates, studies have revealed unexpected immune reactions against PEGylated nanocarriers such as accelerated blood clearance (ABC), involving the production of anti-PEG antibodies at initial injection, which initiates accelerated blood clearance upon subsequent injections, as well as a hypersensitivity reaction referred to as complement activation-related pseudoallergy (CARPA). Further, data have been accumulated indicating consistent yet sometimes controversial correlations between various structural parameters of the PEG-lipids, the properties of the PEGylated LNPs, and the magnitude of the observed adverse effects. Detailed knowledge and comprehension of such correlations are of foremost importance in the efforts to diminish and eliminate the undesirable immune reactions and improve the safety and efficiency of the PEGylated medicines. Here, we present an overview based on analysis of data from the CAS Content Collection regarding the PEGylated LNP immunogenicity and overall safety concerns. A comprehensive summary has been compiled outlining how various structural parameters of the PEG-lipids affect the immune responses and activities of the LNPs, with regards to their efficiency in drug delivery. This Review is thus intended to serve as a helpful resource in understanding the current knowledge in the field, in an effort to further solve the remaining challenges and to achieve full potential.

Development of Hybrid DSPC:DOPC:P(OEGMA950-DIPAEMA) Nanostructures: The Random Architecture of Polymeric Guest as a Key Design Parameter

Hybrid nanoparticles have gained a lot of attention due to their advantageous properties and versatility in pharmaceutical applications. In this perspective, the formation of novel systems and the exploration of their characteristics not only from a physicochemical but also from a biophysical perspective could promote the development of new nanoplatforms with well-defined features. In the current work, lipid/copolymer bilayers were formed in different lipid to copolymer ratios and examined via differential scanning calorimetry as a preformulation study to decipher the interactions between the biomaterials, followed by nanostructure preparation by the thin-film hydration method. Physicochemical and toxicological evaluations were conducted utilizing light scattering techniques, fluorescence spectroscopy, and MTS assay. 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in different weight ratios were the chosen lipids, while a linear random copolymer with pH- and thermoresponsive properties comprised of oligo (ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(diisopropylamino) ethyl methacrylate (DIPAEMA) in different ratios was used. According to our results, non-toxic hybrid nanosystems with stimuli-responsive properties were successfully formulated, and the main parameters influencing their overall performance were the hydrophilic/hydrophobic balance, lipid to polymer ratio, and more importantly the random copolymer topology. Hopefully, this investigation can promote a better understanding of the factors affecting the behavior of hybrid systems.

Neutralization of the new coronavirus by extracting their spikes using engineered liposomes

The devastating COVID-19 pandemic motivates the development of safe and effective antivirals to reduce morbidity and mortality associated with infection. We developed nanoscale liposomes that are coated with the cell receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. Lentiviral particles pseudotyped with the spike protein of SARS-CoV-2 were constructed and used to test the virus neutralization potential of the engineered liposomes. Under TEM, we observed for the first time a dissociation of spike proteins from the pseudovirus surface when the pseudovirus was purified. The liposomes potently inhibit viral entry into host cells by extracting the spike proteins from the pseudovirus surface. As the receptor on the liposome surface can be readily changed to target other viruses, the receptor-coated liposome represents a promising strategy for broad spectrum antiviral development.

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.

Peripheral Regional Anesthesia Using Local Anesthetics: Old Wine in New Bottles?

During the past decade, numerous efforts were undertaken aiming at prolonging the analgesic effect of regional anesthesia. With the development of extended-release formulations and enhanced selectivity for nociceptive sensory neurons, a very promising contribution to the development of pain medications has been achieved. At present, liposomal bupivacaine is the most popular, non-opioid, controlled drug delivery system, but its duration of action, which is still controversially discussed, and its expensiveness have decreased initial enthusiasm. Continuous techniques can be seen as an elegant alternative for providing a prolonged duration of analgesia, but for logistic or anatomical reasons, they are not always the best choice. Therefore, focus has been directed towards the perineural and/or intravenous addition of old and established substances. As for perineural application, most of these so-called 'adjuvants' are used outside their indication, and their pharmacological efficacy is often not or only poorly understood. This review aims to summarize the recent developments for prolonging the duration of regional anesthesia. It will also discuss the potential harmful interactions and side effects of frequently used analgesic mixtures.

Sticking the Landing: Enhancing Liposomal Cell Delivery using Reversible Covalent Chemistry and Caged Targeting Groups

Liposomes are highly effective nanocarriers for encapsulating and delivering a wide range of therapeutic cargo. While advancements in liposome design have improved several pharmacological characteristics, an important area that would benefit from further progress involves cellular targeting and entry. In this concept article, we will focus on recent progress utilizing strategies including reversible covalent bonding and caging groups to activate liposomal cell entry. These approaches take advantage of advancements that have been made in complementary fields including molecular sensing and chemical biology and direct this technology toward controlling liposome cell delivery properties. The decoration of liposomes with groups including boronic acids and cyclic disulfides is presented as a means for driving delivery through reaction with functional groups on cell surfaces. Additionally, caging groups can be exploited to activate cell delivery only upon encountering a target stimulus. These approaches provide promising new avenues for controlling cell delivery in the development of next-generation liposomal therapeutic nanocarriers.

What We Need to Know about Liposomes as Drug Nanocarriers: An Updated Review

Liposomes have been attracted considerable attention as phospholipid spherical vesicles, over the past 40 years. These lipid vesicles are valued in biomedical application due to their ability to carry both hydrophobic and hydrophilic agents, high biocompatibility and biodegradability. Various methods have been used for the synthesis of liposomes, so far and numerous modifications have been performed to introduce liposomes with different characteristics like surface charge, size, number of their layers, and length of circulation in biological fluids. This article provides an overview of the significant advances in synthesis of liposomes via active or passive drug loading methods, as well as describes some strategies developed to fabricate their targeted formulations to overcome limitations of the "first-generation" liposomes.

Assembly methods for asymmetric lipid and polymer-lipid vesicles

Asymmetric unilamellar vesicles are aqueous bodies surrounded by two dissimilar leaflets made from lipids, polymers, or both. They are great models for cell membranes and attractive vehicles in potential biomedicine applications. Despite their promise, asymmetric unilamellar vesicles are not widely studied or adopted in applications. This is largely due to the complexity in generating asymmetric membranes. Recent technical advances in microfluidics have opened doors to high throughput fabrication of asymmetric unilamellar vesicles. In this review, we focus on microfluidic methods for generating asymmetric lipid vesicles, with two dissimilar lipid leaflets, and asymmetric lipid-polymer vesicles, with one lipid leaflet and one polymer leaflet. We also review a few standard non-microfluidic methods for generating asymmetric vesicles. We hope to highlight the improved capability in obtaining asymmetric vesicles through a variety of methods and encourage the wider scientific community to adopt some of these for their own work.

Lipidation of NOD2 Agonists with Adamantane and Stearoyl Moieties Differentially Regulates Their In Vivo Adjuvant Activity

NOD2 is an innate immune receptor that constitutes an important target for the development of small molecule immunopotentiators with great potential to be used as vaccine adjuvants. We report here the results of an in vivo study of the adjuvant properties of a desmuramylpeptide NOD2 agonist SG29 and its lipidated analogs featuring an adamantyl moiety or a stearoyl group. These compounds have been synthesized, incorporated into liposomes, and evaluated for their in vivo adjuvant activity. The characterization of liposome formulations of examined compounds revealed that their size increased in comparison to that of empty liposomes. The introduction of a stearoyl or an adamantane lipophilic anchor into the structure of SG29, to produce SG115 and ZSB63, respectively, substantially improved the in vivo adjuvant activity. Of note, the attachment of the stearoyl moiety produced a Th2-biased immune response, while the incorporation of the adamantyl moiety greatly enhanced the production of total IgG but mostly augmented the production of IgG2a antibodies, which indicated a shift toward a Th1 immune response. The identified bona fide capacity of ZSB63 to initiate a cellular immune response thus highlights its untapped potential as an alternative vaccine adjuvant.

Current treatments after spinal cord injury: Cell engineering, tissue engineering, and combined therapies

Both traumatic and non-traumatic spinal cord injuries (SCIs) can be categorized as damages done to our central nervous system (CNS). The patients' physical and mental health may suffer greatly because of traumatic SCI. With the widespread use of motor vehicles and increasingly aged population, the occurrence of SCI is more frequent than before, creating a considerable burden to global public health. The regeneration process of the spinal cord is hampered by a series of events that occur following SCI like edema, hemorrhage, formation of cystic cavities, and ischemia. An effective strategy for the treatment of SCI and functional recovery still has not been discovered; however, recent advances have been made in bioengineering fields that therapies based on cells, biomaterials, and biomolecules have proved effective in the repair of the spinal cord. In the light of worldwide importance of treatments for SCI, this article aims to provide a review of recent advances by first introducing the physiology, etiology, epidemiology, and mechanisms of SCI. We then put emphasis on the widely used clinical treatments and bioengineering strategies (cell-based, biomaterial-based, and biomolecule-based) for the functional regeneration of the spinal cord as well as challenges faced by scientists currently. This article provides scientists and clinicians with a comprehensive outlook on the recent advances of preclinical and clinical treatments of SCI, hoping to help them find keys to the functional regeneration of SCI.

Multimodal imaging distribution assessment of a liposomal antibiotic in an infectious disease model

Liposomes are promising targeted drug delivery systems with the potential to improve the efficacy and safety profile of certain classes of drugs. Though attractive, there are unique analytical challenges associated with the development of liposomal drugs including human dose prediction given these are multi-component drug delivery systems. In this study, we developed a multimodal imaging approach to provide a comprehensive distribution assessment for an antibacterial drug, GSK2485680, delivered as a liposomal formulation (Lipo680) in a mouse thigh model of bacterial infection to support human dose prediction. Positron emission tomography (PET) imaging was used to track the in vivo biodistribution of Lipo680 over 48 h post-injection providing a clear assessment of the uptake in various tissues and, importantly, the selective accumulation at the site of infection. In addition, a pharmacokinetic model was created to evaluate the kinetics of Lipo680 in different tissues. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) was then used to quantify the distribution of GSK2485680 and to qualitatively assess the distribution of a liposomal lipid throughout sections of infected and non-infected hindlimb tissues at high spatial resolution. Through the combination of both PET and MALDI IMS, we observed excellent correlation between the Lipo680-radionuclide signal detected by PET with the GSK2485680 and lipid component signals detected by MALDI IMS. This multimodal translational method can reduce drug attrition by generating comprehensive biodistribution profiles of drug delivery systems to provide mechanistic insight and elucidate safety concerns. Liposomal formulations have potential to deliver therapeutics across a broad array of different indications, and this work serves as a template to aid in delivering future liposomal drugs to the clinic.

Harnessing Ultrasound for Targeting Drug Delivery to the Brain and Breaching the Blood–Brain Tumour Barrier

Despite significant advances in developing drugs to treat brain tumours, achieving therapeutic concentrations of the drug at the tumour site remains a major challenge due to the presence of the blood–brain barrier (BBB). Several strategies have evolved to enhance brain delivery of chemotherapeutic agents to treat tumours; however, most approaches have several limitations which hinder their clinical utility. Promising studies indicate that ultrasound can penetrate the skull to target specific brain regions and transiently open the BBB, safely and reversibly, with a high degree of spatial and temporal specificity. In this review, we initially describe the basics of therapeutic ultrasound, then detail ultrasound-based drug delivery strategies to the brain and the mechanisms by which ultrasound can improve brain tumour therapy. We review pre-clinical and clinical findings from ultrasound-mediated BBB opening and drug delivery studies and outline current therapeutic ultrasound devices and technologies designed for this purpose.

Atypical vesicles and membranes with monolayer and multilayer structures formed by graft copolymers with diblock side-chains: nonlamellar structures and curvature-enhanced permeability

Graft copolymers with diblock side-chains A_m(-graft-B₃A_y)_n in a selective solvent have been reported to self-assemble into vesicles, but the structure is expected to differ distinctly from those of lipid bilayers. Surprisingly, the number of alternating hydrophobic A-block and hydrophilic B-block layers in the vesicle can vary from a monolayer to multilayers such as the hepta-layer, subject to the same copolymer concentration. The area density of the copolymer layer is not uniform across the membrane. This structural difference among different layers is attributed to the neighboring environment and the curvature of the layer. Because of the unusual polymer conformations, nonlamellar structures of polymersomes are formed, and they are much more intricate than those of liposomes. In fact, a copolymer can contribute to a single or two hydrophilic layers, and it can provide up to three hydrophobic layers. The influence of the backbone length (m) and side-chain length (y) and the permeation dynamics are also studied. The thickness of hydrophobic layers is found to increase with increasing side-chain length but is not sensitive to the backbone length. Although the permeation time increases with the layer number for planar membranes, the opposite behavior is observed for spherical vesicles owing to the curvature-enhanced permeability associated with Laplace pressure.

Diagnostic biomolecules and combination therapy for pre-eclampsia

Pre-eclampsia (PE), associated with placental malperfusion, is the primary reason for maternal and perinatal mortality and morbidity that can cause vascular endothelial injury and multi-organ injury. Despite considerable research efforts, no pharmaceutical has been shown to stop disease progression. If women precisely diagnosed with PE can achieve treatment at early gestation, the maternal and fetal outcomes can be maximally optimized by expectant management. Current diagnostic approaches applying maternal characteristics or biophysical markers, including blood test, urine analysis and biophysical profile, possess limitations in the precise diagnosis of PE. Biochemical factor research associated with PE development has generated ambitious diagnostic targets based on PE pathogenesis and dissecting molecular phenotypes. This review focuses on current developments in biochemical prediction of PE and the corresponding interventions to ameliorate disease progression, aiming to provide references for clinical diagnoses and treatments.

Metformin and histone deacetylase inhibitor based anti-inflammatory nanoplatform for epithelial-mesenchymal transition suppression and metastatic tumor treatment

Epithelial-mesenchymal transition (EMT), a differentiation process with aberrant changes of tumor cells, is identified as an initial and vital procedure for metastatic processes. Inflammation is a significant inducer of EMT and provides an indispensable target for blocking EMT, however, an anti-inflammatory therapeutic with highlighted safety and efficacy is deficient. Metformin is a promising anti-inflammatory agent with low side effects, but tumor monotherapy with an anti-inflammation drug could generate therapy resistance, cell adaptation or even promote tumor development. Combination therapies with various anti-inflammatory mechanisms can be favorable options improving therapeutic effects of metformin, here we develop a tumor targeting hybrid micelle based on metformin and a histone deacetylase inhibitor propofol-docosahexaenoic acid for efficient therapeutic efficacies of anti-inflammatory drugs. Triptolide is further encapsulated in hybrid micelles for orthotopic tumor therapies. The final multifunctional nanoplatforms (HAOPTs) with hyaluronic acid (HA) modification can target tumor efficiently, inhibit tumor cell EMT processes, repress metastasis establishment and suppress metastatic tumor development in a synergistic manner. Collectively, the results afford proof of concept that the tumor targeting anti-inflammatory nanoplatform can provide a potent, safe and clinical translational approach for EMT inhibition and metastatic tumor therapy.

Nanotechnological interventions of the microbiome as a next-generation antimicrobial therapy

The rise of antimicrobial resistance (AMR) impacts public health due to the diminished potency of existing antibiotics. The microbiome plays an important role in the host's immune system activity and shows the history of exposure to antimicrobials and its manipulation in combating antimicrobial resistance. Advancements in gene technologies, DNA sequencing, and computational biology have emerged as powerful platforms to better understand the relationship between animals and microorganisms (MOs). The past few years have witnessed an increase in the use of nanotechnology, both in industry and in academia, as tools to tackle antimicrobial resistance. New strategies of microbiome manipulation have been developed, such as the use of prebiotics, probiotics, peptides, antibodies, an appropriate diet, phage therapy, and the use of various nanotechnological techniques. Owing to the research outcomes, targeted delivery of antimicrobials with some modifications with nanoparticles can lead to the destruction of resistant microbial cells. In addition, nanoparticles have been studied for their potential antimicrobial effects both in vitro and in vivo. In this review, we highlight key opportunistic areas for applying nanotechnologies with the aim of manipulating the microbiome for the treatment of antimicrobial resistance. Besides providing a detailed review on various nanomaterials, technologies, opportunities, technical needs, and potential approaches for the manipulation of the microbiome to address these challenges, we discuss future challenges and our perspective.

Long wavelength-emissive Ru(II) metallacycle-based photosensitizer assisting in vivo bacterial diagnosis and antibacterial treatment

Ruthenium (Ru) complexes are developed as latent emissive photosensitizers for cancer and pathogen photodiagnosis and therapy. Nevertheless, most existing Ru complexes are limited as photosensitizers in terms of short excitation and emission wavelengths. Herein, we present an emissive Ru(II) metallacycle (herein referred to as 1) that is excited by 808-nm laser and emits at a wavelength of ∼1,000 nm via coordination-driven self-assembly. Metallacycle 1 exhibits good optical penetration (∼7 mm) and satisfactory reactive oxygen species production properties. Furthermore, 1 shows broad-spectrum antibacterial activity (including against drug-resistant Escherichia coli) as well as low cytotoxicity to normal mammalian cells. In vivo studies reveal that 1 is employed in precise, second near-infrared biomedical window fluorescent imaging-guided, photo-triggered treatments in Staphylococcus aureus-infected mice models, with negligible side effects. This work thus broads the applications of supramolecular photosensitizers through the strategy of lengthening their wavelengths.

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.

Effects of hydrocarbon chain on the vesicle size distribution, kinetics of average size, bending modulus, and elastic modulus of lipid membranes

The effects of the hydrocarbon chain of lipids on the size distribution of giant unilamellar vesicles (GUVs), kinetics of average size, bending modulus, and elastic modulus of membranes have been investigated. 1,2-dioleoyl-sn-glycero-3-phosphocholine (18:1 (Δ9-Cis) PC (DOPC)), 1,2-dipalmitoleoyl-sn-glycero-3-phosphocholine (16:1 (Δ9-Cis) PC), and 1,2-ditridecanoyl-sn-glycerol-3-phosphocholine (13:0 PC (DTPC)) lipids were considered. The number of hydrocarbons in a chain of the corresponding lipid was 18, 16, and 13. GUVs were prepared using the natural swelling method under incubation times of 20, 40, 60, 90, 120, and 180 min. The size distribution of vesicles was fitted using the lognormal distribution. The average sizes of DOPC, 16:1 (Δ9-Cis) PC, and DTPC-GUVs increased with the incubation time until 120 min, and then remained steady at 16.7 ± 0.2, 15.2 ± 0.4 and 12.0 ± 0.3 µm for the corresponding lipids. The average size at equilibrium state increased with the number of hydrocarbons. The incubation time-dependent average size was fitted with an exponential growth equation, and then the kinetic constants of 0.028 ± 0.004, 0.036 ± 0.007, and 0.083 ± 0.009 min^-1 for DOPC, 16:1 (Δ9-Cis) PC, and DTPC-GUVs, respectively, were obtained. The equilibrium size distribution was fitted by the theoretical equation, and the bending modulus for DOPC, 16:1 (Δ9-Cis) PC, and DTPC membranes were 19.5 ± 0.2, 18.5 ± 0.1 and 14.3 ± 0.1 k_BT, respectively. The bending modulus increased with the number of hydrocarbons. The elastic modulus of these membranes was 261 mN/m with a 4% fluctuation. The correlation between the average size and the square root of the bending modulus was supported by theoretical analysis.

Protein-liposome interactions: the impact of surface charge and fluidisation effect on protein binding

At the dawn of a new nanotechnological era in the pharmaceutical field, it is very important to examine and understand all the aspects that influence in vivo behaviour of nanoparticles. In this point of view, the interactions between serum proteins and liposomes with incorporated anionic, cationic, and/or PEGylated lipids were investigated to elucidate the role of surface charge and bilayer fluidity in protein corona's formation. 1,2-dipalmitoyl-sn-glycero-3- phosphocholine (DPPC), hydrogenated soybean phosphatidylcholine (HSPC), and 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC) liposomes with the presence or absence of 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DPPG), 1,2-di-(9Z-octadecenoyl)-3-trimethylammonium-propane (chloride salt) (DOTAP), and/or 1,2-dipalmitoylsn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-5000] (DPPE-PEG 5000) lipids were prepared by the thin-film hydration method. The evaluation of their biophysical characteristics was enabled by differential scanning calorimetry and dynamic and electrophoretic light scattering. The physicochemical characteristics of mixed liposomes were compared before and after exposure to foetal bovine serum (FBS) and were correlated to calorimetric data. Our results indicate protein binding to all liposomal formulations. However, it is highlighted the importance of surface charge and fluidisation effect to the extent of protein adsorption. Additionally, considering the extensive use of cationic lipids for innovative delivery platforms, we deem PEGylation a key parameter, because even in a small proportion can reduce protein binding, and thus fast clearance and extreme toxicity without affecting positive charge. This study is a continuation of our previous work about protein-liposome interactions and fraction of stealthiness (Fs) parameter, and hopefully a design road map for drug and gene delivery.

Recent advances in porous nanomaterials-based drug delivery systems for cancer immunotherapy

Cancer immunotherapy is a novel therapeutic regimen because of the specificity and durability of immune modulations to treat cancers. Current cancer immunotherapy is limited by some barriers such as poor response rate, low tumor specificity and systemic toxicities. Porous nanomaterials (PNMs) possess high loading capacity and tunable porosity, receiving intense attention in cancer immunotherapy. Recently, novel PNMs based drug delivery systems have been employed in antitumor immunotherapy to enhance tissue or organ targeting and reduce immune-related adverse events. Herein, we summarize the recent progress of PNMs including inorganic, organic, and organic–inorganic hybrid ones for cancer immunotherapy. The design of PNMs and their performance in cancer immunotherapy are discussed in detail, with a focus on how those designs can address the challenges in current conventional immunotherapy. Lastly, we present future directions of PNMs for cancer immunotherapy including the challenges and research gaps, providing new insights about the design of PNMs for efficient cancer immunotherapy with better performance as powerful weapons against tumors. Finally, we discussed the relevant challenges that urgently need to be addressed in clinical practice, coupled with corresponding solutions to these problems.

Determination of lipid content and stability in lipid nanoparticles using ultra high-performance liquid chromatography in combination with a Corona Charged Aerosol Detector

For many years, lipid nanoparticles (LNPs) have been used as delivery vehicles for various payloads (especially various oligonucleotides and mRNA), finding numerous applications in drug and vaccine development. LNP stability and bilayer fluidity are determined by the identities and the amounts of the various lipids employed in the formulation and LNP efficacy is determined in large part by the lipid composition which usually contains a cationic lipid, a PEG-lipid conjugate, cholesterol, and a zwitterionic helper phospholipid. Analytical methods developed for LNP characterization must be able to determine not only the identity and content of each individual lipid component (i.e., the parent lipids), but also the associated impurities and degradants. In this work, we describe an efficient and sensitive reversed-phase chromatographic method with charged aerosol detection (CAD) suitable for this purpose. Sample preparation diluent and mobile phase pH conditions are critical and have been optimized for the lipids of interest. This method was validated for its linearity, accuracy, precision, and specificity for lipid analysis to support process and formulation development for new drugs and vaccines.

Molecular Switches—Tools for Imparting Control in Drug Delivery Systems

Cancer is a globally prevalent cause of premature mortality. Of growing interest is the development of novel anticancer therapies and the optimisation of associated risks. Major issues presently facing conventional anticancer therapies include systemic toxicity, poor solubility, membrane permeability, and multidrug resistance Nanocarriers have been employed to address these issues. Nanocarriers encapsulate anticancer drugs, enabling them to bypass biological barriers and minimise their adverse side effects. These drug delivery systems offer extensive benefits as they can be modified to gravitate towards specific environmental conditions. To further enhance the safety and efficacy of these drug carriers, modern developments have included incorporating a molecular switching mechanism into their structure. These molecular switches are responsive to endogenous and exogenous stimuli and may undergo reversible and repeatable conformational changes when activated. The incorporation of molecular switches can, therefore, impart stimuli-responsive drug-release control on a DDS. These stimuli can then be manipulated to offer precise dosage control over the drug release at a specific target site. This review discusses recent developments in the design of DDSs incorporating light and pH-responsive molecular switches as drug release controllers.

Lipid-Coated CaCO3 Nanoparticles as a Versatile pH-Responsive Drug Delivery Platform to Enable Combined Chemotherapy of Breast Cancer

The development of smart drug delivery nanocarriers for tumor-targeted delivery and controllable release of therapeutic agents is appealing to achieve effective cancer chemotherapy. We herein use CaCO₃ nanoparticles as the core to load doxorubicin (DOX) and direct the assembly of amphiphilic oxaliplatin prodrugs (Pt(IV)) in the presence of other commercial lipids. The obtained DOX-Pt(IV)-CaCO₃-PEG with excellent physiological stability exhibits instant pH-responsive degradation, thus enabling efficient pH-dependent release of DOX. Via detailed pharmacokinetic study, it is shown that DOX-Pt(IV)-CaCO₃-PEG shows significantly improved pharmacokinetic behaviors compared to these free drugs, featured in prolonged blood circulation time and superior tumor homing efficacy. Resultantly, treatment with systemic administration of DOX-Pt(IV)-CaCO₃-PEG was the most effective in suppressing the growth of tumors in Balb/c mice. This study highlights that our liposomal CaCO₃ is a robust and biocompatible platform for preparing pH-responsive drug delivery systems, due to its multifaceted drug loading capacity, and thus is promising for potential clinical translation.

Effects of cholesterol on the size distribution and bending modulus of lipid vesicles

The influence of cholesterol fraction in the membranes of giant unilamellar vesicles (GUVs) on their size distributions and bending moduli has been investigated. The membranes of GUVs were synthesized by a mixture of two elements: electrically neutral lipid 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol and also a mixture of three elements: electrically charged lipid 1,2-dioleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DOPG), DOPC and cholesterol. The size distributions of GUVs have been presented by a set of histograms. The classical lognormal distribution is well fitted to the histograms, from where the average size of vesicle is obtained. The increase of cholesterol content in the membranes of GUVs increases the average size of vesicles in the population. Using the framework of Helmholtz free energy of the system, the theory developed by us is extended to explain the experimental results. The theory determines the influence of cholesterol on the bending modulus of membranes from the fitting of the proper histograms. The increase of cholesterol in GUVs increases both the average size of vesicles in population and the bending modulus of membranes.

Design of a Metallacycle-Based Supramolecular Photosensitizer for In Vivo Image-Guided Photodynamic Inactivation of Bacteria

Bacterial infection is one of the greatest threats to public health. In vivo real-time monitoring and effective treatment of infected sites through non-invasive techniques, remain a challenge. Herein, we designed a PtII metallacycle-based supramolecular photosensitizer through the host-guest interaction between a pillar[5]arene-modified metallacycle and 1-butyl-4-[4-(diphenylamino)styryl]pyridinium. Leveraging the aggregation-induced emission supramolecular photosensitizer, we improved fluorescence performance and antimicrobial photodynamic inactivation. In vivo studies revealed that it displayed precise fluorescence tracking of S. aureus-infected sites, and in situ performed image-guided efficient PDI of S. aureus without noticeable side effects. These results demonstrated that metallacycle combined with host-guest chemistry could provide a paradigm for the development of powerful photosensitizers for biomedicine.

Folate-Targeted Liposomal Formulations Improve Effects of Methotrexate in Murine Collagen-Induced Arthritis

Methotrexate (MTX) is first-line therapy for the treatment of rheumatoid arthritis (RA), however, its use may be limited by side effects notably post-injection malaise. When patients are intolerant or become unresponsive, second-line or antibody therapy may be indicated. A folate-targeted liposomal formulation of MTX (FL-MTX) is tropic to arthritic paws and prevents the onset of collagen-induced arthritis (CIA) in the mouse. We optimized the drug-to-lipid molar ratio to 0.15 and demonstrated the therapeutic efficacy of this form at 2 mg/kg MTX intraperitoneal (i.p.) twice a week. These improved liposomes were present in inflamed joints in proportion to the degree of swelling of the paw and bone remodeling activity. FL-MTX had lower hepatic and renal elimination of MTX than the free substance. FL-MTX provided equivalent results when given i.p. or subcutaneous (s.c.) and FL-MTX 2 mg/kg (drug/lipid 0.15), twice weekly, was similar to or more effective than 35 mg/kg MTX (same route and schedule) in reducing the incidence and swelling in the murine CIA model. These results suggest that FL-MTX is a more potent nanotherapeutic formulation than free MTX treatment. Its potential benefits for patients may include reduced frequency of treatment and lower overall doses for a given response.

Molecular dynamics study of the internalization of cell-penetrating peptides containing unnatural amino acids across membranes

Peptide-based delivery systems that deliver target molecules into cells have been gaining traction. These systems need cell-penetrating peptides (CPPs), which have the remarkable ability to penetrate into biological membranes and help internalize different cargoes into cells through the cell membranes. The molecular internalization mechanism and structure-function relationships of CPPs are not clear, although the incorporation of nonproteinogenic amino acids such as α-aminoisobutyric acid (Aib) has been reported to increase their helicity, biostability and penetration efficiencies. Here, we used molecular dynamics to study two Aib-containing CPPs, poly(LysAibAla)₃ (KAibA) and poly(LysAibGly)₃ (KAibG), that previously showed high cell internalization efficiency. KAibA and KAibG displayed the lowest internalization energies among the studied CPPs, showing distinct internalization mechanisms depending on the lipid composition of the model membranes. The presence of Aib residues allows these CPPs to adopt amphipathic folding to efficiently penetrate through the membranes. Elucidating how Aib incorporation affects CPP-membrane binding and interactions is beneficial for the design of CPPs for efficient intracellular delivery.

Stem Cell Mimicking Nanoencapsulation for Targeting Arthritis

Mesenchymal stem cells (MSCs) are considered a promising regenerative therapy due to their ability to migrate toward damaged tissues. The homing ability of MSCs is unique compared with that of non-migrating cells and MSCs are considered promising therapeutic vectors for targeting major cells in many pathophysiological sites. MSCs have many advantages in the treatment of malignant diseases, particularly rheumatoid arthritis (RA). RA is a representative autoimmune disease that primarily affects joints, and secreted chemokines in the joints are well recognized by MSCs following their migration to the joints. Furthermore, MSCs can regulate the inflammatory process and repair damaged cells in the joints. However, the functionality and migration ability of MSCs injected in vivo still show insufficient. The targeting ability and migration efficiency of MSCs can be enhanced by genetic engineering or modification, eg, overexpressing chemokine receptors or migration-related genes, thus maximizing their therapeutic effect. However, there are concerns about genetic changes due to the increased probability of oncogenesis resulting from genome integration of the viral vector, and thus, clinical application is limited. Furthermore, it is suspected that administering MSCs can promote tumor growth and metastasis in xenograft and orthotopic models. For this reason, MSC mimicking nanoencapsulations are an alternative strategy that does not involve using MSCs or bioengineered MSCs. MSC mimicking nanoencapsulations consist of MSC membrane-coated nanoparticles, MSC-derived exosomes and artificial ectosomes, and MSC membrane-fused liposomes with natural or genetically engineered MSC membranes. MSC mimicking nanoencapsulations not only retain the targeting ability of MSCs but also have many advantages in terms of targeted drug delivery. Specifically, MSC mimicking nanoencapsulations are capable of encapsulating drugs with various components, including chemotherapeutic agents, nucleic acids, and proteins. Furthermore, there are fewer concerns over safety issues on MSC mimicking nanoencapsulations associated with mutagenesis even when using genetically engineered MSCs, because MSC mimicking nanoencapsulations use only the membrane fraction of MSCs. Genetic engineering is a promising route in clinical settings, where nano-encapsulated technology strategies are combined. In this review, the mechanism underlying MSC homing and the advantages of MSC mimicking nanoencapsulations are discussed. In addition, genetic engineering of MSCs and MSC mimicking nanoencapsulation is described as a promising strategy for the treatment of immune-related diseases.