In vivo toxicity of cationic micelles and liposomes

Integrated therapy platform of exosomal system: hybrid inorganic/organic nanoparticles with exosomes for cancer treatment

Recent studies have found that exosomes or extracellular vehicles (EVs) are associated with cancer metastasis, disease progression, diagnosis, and treatment, leading to a rapidly emerging area of exocrine vesicle research. Relying on the superior targeting function and bio-compatibility of exosomes, researchers have been able to deliver drugs to cancer stem cells deep within tumors in mouse models. Despite significant efforts made in this relatively new field of exosome research, progress has been held back by challenges such as inefficient separation methods, difficulties in characterization/tracking, and a lack of specific biomarkers. Therefore, current researches are devoted to combining nanomaterials with exosomes to improve these shortcomings. Adding inorganic/organic nanoparticles such as artificial liposomes and iron oxide can bring more drug options and various fluorescent or magnetic diagnostic possibilities to the exosome system. Moreover, the applications of exosomes need to be further evaluated under actual physiological conditions. This review article highlights the potential of exosome-biomimetic nanoparticles for their use as drug carriers to improve the efficacy of anticancer therapy.

Intraperitoneal administration of nanoparticles containing tocopheryl succinate prevents peritoneal dissemination

Intraperitoneal administration of anticancer nanoparticles is a rational strategy for preventing peritoneal dissemination of colon cancer owing to the prolonged retention of nanoparticles in the abdominal cavity. However, instability of nanoparticles in body fluids causes inefficient retention, reducing its anticancer effects. We have previously developed anticancer nanoparticles containing tocopheryl succinate, which showed high in vivo stability and multifunctional anticancer effects. In the present study, we have demonstrated that peritoneal dissemination derived from colon cancer was prevented by intraperitoneal administration of tocopheryl succinate nanoparticles. The biodistribution of tocopheryl succinate nanoparticles was evaluated by inductively coupled plasma mass spectroscopy and imaging analysis in mice administered quantum dot encapsulated tocopheryl succinate nanoparticles. Intraperitoneal administration of tocopheryl succinate nanoparticles showed longer retention in the abdominal cavity than by its intravenous administration. Moreover, due to effective biodistribution, tumor growth was prevented by intraperitoneal administration of tocopheryl succinate nanoparticles. Furthermore, the anticancer effect was attributed to the inhibition of cancer cell proliferation and improvement of the intraperitoneal microenvironment, such as decrease in the levels of vascular endothelial growth factor A, interleukin 10, and M2-like phenotype of tumor-associated macrophages. Collectively, intraperitoneal administration of tocopheryl succinate nanoparticles is expected to have multifaceted antitumor effects against colon cancer with peritoneal dissemination.

Encapsulation of Hydrophilic Compounds in Small Extracellular Vesicles: Loading Capacity and Impact on Vesicle Functions

Their natural functions in intercellular communication render extracellular vesicles (EV) highly attractive for drug delivery applications. However, the loading efficiency of present methods to incorporate particularly hydrophilic low molecular weight drugs of biomedical interest is largely unexplored, as is the impact these methods may have on the intrinsic structural and biological vesicle properties. Here, different methods are exploited to incorporate hydrophilic non-membrane permeable compounds into stem cell-derived small EV, and to assess the vesicle characteristics after the different loading processes. When comparing several methods head-to-head, the loading capacity increases in the order saponin ≤ sonication < fusion < freeze-thawing ≤ osmotic shock. Interestingly, the structural and biological functions of small EV are dependent on the applied encapsulation process, with the functional properties being altered at a greater extent. Therefore, the importance of including additional characterization parameters to probe alterations of the biological functionality of small EV is clearly demonstrated. Here, freeze-thawing and particularly the osmotic shock have proven to be the most appropriate methods for EV loading, as they achieve a high drug encapsulation and yet preserve the investigated structural and biological vesicle characteristics.

Transfersome Hydrogel Containing 5-Fluorouracil and Etodolac Combination for Synergistic Oral Cancer Treatment

Oral cancer is one of the most common malignancies with an increased rate of incidence. 5-Fluorouracil (5FU) is an effective chemotherapeutic indicated for oral cancer treatment. Etodolac (Et), a cyclooxygenase-2 inhibitor, can be used as an adjuvant agent to sensitize cancer cells to chemotherapy. The aim of this work was to prepare and characterize 5FU and Et dual drug-loaded transfersomes to treat oral cancer. Transfersomes were prepared by thin-film hydration method and characterized for the average particle size and zeta-potential using dynamic light scattering and scanning electron microscopy techniques. The prepared transfersomes were further characterized for their drug loading, entrapment efficiencies using amicon centrifuge tubes and drug release behavior using cellulose membrane. The synergistic activity of dual drug-loaded transfersomes was studied in FaDu oral cancer cells. Results showed that the average particle size, polydispersity index, and zeta potential were 91±6.4 nm, 0.28±0.03, and (-)46.9±9.5 mV, respectively, for 5FU- and Et (1:1)-loaded transfersomes. The highest encapsulation efficiency achieved was 36.9±3.8% and 79.8±6.4% for 5FU and Et (1:1), respectively. Growth inhibition studies in FaDu cells using different concentrations of 5FU and Et showed a combination index of 0.36, indicating a synergistic effect. The FaDu cell uptake of drug-loaded transfersomes was significantly (p<0.05) greater than that of free drugs. The transfersome hydrogel made of HPMC (2% w/w) showed similar flux, lag time, and permeation coefficient as that of drug-loaded transfersomes across excised porcine buccal tissue. In conclusion, 5FU and Et transfersome hydrogel can be developed for localized delivery to treat oral cancer.

Nanoparticulate strategies for the delivery of miRNA mimics and inhibitors in anticancer therapy and its potential utility in oral submucous fibrosis

MicroRNAs (miRNAs) are naturally occurring noncoding RNAs with multiple functionalities. They are dysregulated in several conditions and can serve as disease biomarkers, therapeutic targets and therapeutic agents. Translation of miRNA therapeutics to the clinic poses several challenges related to the safe and effective delivery of these agents to the site of action. Nanoparticulate carriers hold promise in this area by enhancing targeting efficiency and reducing off-target effects. This paper reviews recent advances in the delivery strategies of miRNAs in anticancer therapy, with a focus on lipid-based, polymeric, inorganic platforms, cell membrane-derived vesicles and bacterial minicells. Additionally, this review explores the potentiality of miRNAs in the treatment of oral submucous fibrosis, a potentially premalignant condition of the oral cavity with no definitive treatment to date.

Kidney protective potential of lactoferrin: pharmacological insights and therapeutic advances

Kidney disease is becoming a global public health issue. Acute kidney injury (AKI) and chronic kidney disease (CKD) have serious adverse health outcomes. However, there is no effective therapy to treat these diseases. Lactoferrin (LF), a multi-functional glycoprotein, is protective against various pathophysiological conditions in various disease models. LF shows protective effects against AKI and CKD. LF reduces markers related to inflammation, oxidative stress, apoptosis, and kidney fibrosis, and induces autophagy and mitochondrial biogenesis in the kidney. Although there are no clinical trials of LF to treat kidney disease, several clinical trials and studies on LF-based drug development are ongoing. In this review, we discussed the possible kidney protective mechanisms of LF, as well as the pharmacological and therapeutic advances. The evidence suggests that LF may become a potent pharmacological agent to treat kidney diseases.

Engineered CRISPR-Cas systems for the detection and control of antibiotic-resistant infections

Antibiotic resistance is spreading rapidly around the world and seriously impeding efforts to control microbial infections. Although nucleic acid testing is widely deployed for the detection of antibiotic resistant bacteria, the current techniques-mainly based on polymerase chain reaction (PCR)-are time-consuming and laborious. There is an urgent need to develop new strategies to control bacterial infections and the spread of antimicrobial resistance (AMR). The CRISPR-Cas system is an adaptive immune system found in many prokaryotes that presents attractive opportunities to target and edit nucleic acids with high precision and reliability. Engineered CRISPR-Cas systems are reported to effectively kill bacteria or even revert bacterial resistance to antibiotics (resensitizing bacterial cells to antibiotics). Strategies for combating antimicrobial resistance using CRISPR (i.e., Cas9, Cas12, Cas13, and Cas14) can be of great significance in detecting bacteria and their resistance to antibiotics. This review discusses the structures, mechanisms, and detection methods of CRISPR-Cas systems and how these systems can be engineered for the rapid and reliable detection of bacteria using various approaches, with a particular focus on nanoparticles. In addition, we summarize the most recent advances in applying the CRISPR-Cas system for virulence modulation of bacterial infections and combating antimicrobial resistance.

Intercalation-Driven Formation of siRNA Nanogels for Cancer Therapy

RNA interference (RNAi) is a powerful approach in the treatment of various diseases including cancers. The clinical translation of small interfering RNA (siRNA)-based therapy requires safe and efficient delivery vehicles. Here, we report a siRNA nanogels (NG)-based delivery vehicle, which is driven directly by the intercalation between nucleic acid bis-intercalator and siRNA molecules. The intercalation-based siRNA NG exhibits good physiological stability and can enter cells efficiently via different endocytosis pathways. Furthermore, the siRNA NG can not only silence the target genes in vitro but also significantly inhibit the tumor growth in vivo. Therefore, this study provides an intercalation-based strategy for the development of a siRNA delivery platform for cancer therapy. To the best of our knowledge, this is the first report of the intercalation-driven siRNA NG.

Boosting ionizable lipid nanoparticle-mediated in vivo mRNA delivery through optimization of lipid amine-head groups

In vitro transcribed messenger RNA (IVT-mRNA) holds great promise for the development of novel therapeutics, such as immunotherapy and vaccination. However, the main obstacle towards clinical translation is the lack of effective delivery systems. Herein, we have synthesized a series of ionizable lipids by the addition of an alkyl-acrylate to amine-containing molecules (amine-head groups) as a key component of ionizable lipid nanoparticles (iLNPs) and thoroughly investigated the impact of the amine-head group on the transfection efficiency of iLNPs/mRNA lipoplexes both in vitro and in vivo. The top-performing iLNP (114-iLNP), composed of a lipid with spermine as the amine-head, demonstrated the strongest cellular uptake, membrane disruption and endosomal escape, and further achieved the highest protein expression in HeLa cells with more than 95% transfection efficiency. More importantly, intravenous injection of luciferase mRNA loaded 114-iLNP enables the most efficacious in vivo protein expression, predominantly in the liver. Biodistribution and biosafety evaluation of 114-iLNP/mRNA further demonstrated the liver-selective delivery capability and high biocompatibility. In addition, 114-iLNP facilitated efficient in vivo delivery of a therapeutic gene, human erythropoietin (hEPO) mRNA, and induced hEPO expression in a dose-dependent manner. Therefore, these results demonstrate that the amine-head group in the ionizable lipid significantly affects mRNA delivery efficacy and the leading candidate 114-iLNP composed of a lipid with spermine as the amine-head has great potential for mRNA therapeutics development.

Emerging innate biological properties of nano-drug delivery systems: A focus on PAMAM dendrimers and their clinical potential

Drug delivery systems or vectors are usually needed to improve the bioavailability and effectiveness of a drug through improving its pharmacokinetics/pharmacodynamics at an organ, tissue or cellular level. However, emerging technologies with sensitive readouts as well as a greater understanding of physiological/biological systems have revealed that polymeric drug delivery systems are not biologically inert but can have innate or intrinsic biological actions. In this article, we review the emerging multiple innate biological/toxicological properties of naked polyamidoamine (PAMAM) dendrimer delivery systems in the absence of any drug cargo and discuss their correlation with the defined physicochemical properties of PAMAMs in terms of molecular size (generation), architecture, surface charge and chemistry. Further, we assess whether any of the reported intrinsic biological actions of PAMAMs such as their antimicrobial activity or their ability to sequester glucose and modulate key protein interactions or cell signaling pathways, can be exploited clinically such as in the treatment of diabetes and its complications.

Synergies between therapeutic ultrasound, gene therapy and immunotherapy in cancer treatment

Due to the ease of use and excellent safety profile, ultrasound is a promising technique for both diagnosis and site-specific therapy. Ultrasound-based techniques have been developed to enhance the pharmacokinetics and efficacy of therapeutic agents in cancer treatment. In particular, transfection with exogenous nucleic acids has the potential to stimulate an immune response in the tumor microenvironment. Ultrasound-mediated gene transfection is a growing field, and recent work has incorporated this technique into cancer immunotherapy. Compared with other gene transfection methods, ultrasound-mediated gene transfection has a unique opportunity to augment the intracellular uptake of nucleic acids while safely and stably modulating the expression of immunostimulatory cytokines. The development and commercialization of therapeutic ultrasound systems further enhance the potential translation. In this Review, we introduce the underlying mechanisms and ongoing preclinical studies of ultrasound-based techniques in gene transfection for cancer immunotherapy. Furthermore, we expand on aspects of therapeutic ultrasound that impact gene therapy and immunotherapy, including tumor debulking, enhancing cytokines and chemokines and altering nanoparticle pharmacokinetics as these effects of ultrasound cannot be fully dissected from targeted gene therapy. We finally explore the outlook for this rapidly developing field.

Safety and Toxicity Issues of Therapeutically Used Nanoparticles from the Oral Route

The emerging science of nanotechnology sparked a research attention in its potential benefits in comparison to the conventional materials used. Oral products prepared via nanoparticles (NPs) have garnered great interest worldwide. They are used commonly to incorporate nutrients and provide antimicrobial activity. Formulation into NPs can offer opportunities for targeted drug delivery, improve drug stability in the harsh environment of the gastrointestinal (GI) tract, increase drug solubility and bioavailability, and provide sustained release in the GI tract. However, some issues like the management of toxicity and safe handling of NPs are still debated and should be well concerned before their application in oral preparations. This article will help the reader to understand safety issues of NPs in oral drug delivery and provides some recommendations to the use of NPs in the drug industry.

Micelles Based on Lysine, Histidine, or Arginine: Designing Structures for Enhanced Drug Delivery

Natural amino acids and their derivatives are excellent building blocks of polymers for various biomedical applications owing to the non-toxicity, biocompatibility, and ease of multifunctionalization. In the present review, we summarized the common approaches to designing and constructing functional polymeric micelles based on basic amino acids including lysine, histidine, and arginine and highlighted their applications as drug carriers for cancer therapy. Different polypeptide architectures including linear polypeptides and dendrimers were developed for efficient drug loading and delivery. Besides, polylysine- and polyhistidine-based micelles could enable pH-responsive drug release, and polyarginine can realize enhanced membrane penetration and gas therapy by generating metabolites of nitric oxide (NO). It is worth mentioning that according to the structural or functional characteristics of basic amino acids and their derivatives, key points for designing functional micelles with excellent drug delivery efficiency are importantly elaborated in order to pave the way for exploring micelles based on basic amino acids.

Safety and Efficacy Evaluation In Vivo of a Cationic Nucleolipid Nanosystem for the Nanodelivery of a Ruthenium(III) Complex with Superior Anticancer Bioactivity

Simple Summary

The availability of selective, effective, and safe anticancer agents is a major challenge in the field of cancer research. As part of a multidisciplinary research project, in recent years our group has proposed an original class of nanomaterials for the delivery of new anticancer drugs based on ruthenium(III) complexes. In cellular models, these nanosystems have been shown to be effective in counteracting growth and proliferation of human breast cancer cells. Compared to conventional metallochemotherapeutics such as platinum-based agents whose clinical practice is associated with serious undesirable effects, ruthenium complexes share improved biochemical profiles making them more selective towards cancer cells and less cytotoxic to healthy cells. Their combination with biocompatible nanocarriers further enhances these promising features, as here showcased by our research carried out in an animal model which underscores the efficacy and safety in vivo of one of our most promising ruthenium-based nanosystems.

Abstract

Selectivity and efficacy towards target cancer cells, as well as biocompatibility, are current challenges of advanced chemotherapy powering the discovery of unconventional metal-based drugs and the search for novel therapeutic approaches. Among second-generation metal-based chemotherapeutics, ruthenium complexes have demonstrated promising anticancer activity coupled to minimal toxicity profiles and peculiar biochemical features. In this context, our research group has recently focused on a bioactive Ru(III) complex—named AziRu—incorporated into a suite of ad hoc designed nucleolipid nanosystems to ensure its chemical stability and delivery. Indeed, we proved that the structure and properties of decorated nucleolipids can have a major impact on the anticancer activity of the ruthenium core. Moving in this direction, here we describe a preclinical study performed by a mouse xenograft model of human breast cancer to establish safety and efficacy in vivo of a cationic Ru(III)-based nucleolipid formulation, named HoThyRu/DOTAP, endowed with superior antiproliferative activity. The results show a remarkable reduction in tumour with no evidence of animal suffering. Blood diagnostics, as well as biochemical analysis in both acute and chronic treated animal groups, demonstrate a good tolerability profile at the therapeutic regimen, with 100% of mice survival and no indication of toxicity. In addition, ruthenium plasma concentration analysis and tissue bioaccumulation were determined via appropriate sampling and ICP-MS analysis. Overall, this study supports both the efficacy of our Ru-containing nanosystem versus a human breast cancer model and its safety in vivo through well-tolerated animal biological responses, envisaging a possible forthcoming use in clinical trials.

Folate targeted hybrid lipo-polymeric nanoplexes containing docetaxel and miRNA-34a for breast cancer treatment

In spite of established evidence of the synergistic combination of hydrophobic anticancer molecule and microRNA for breast cancer treatment, their in vivo delivery has not been realized owing to their instability in the biological milieu and varied physicochemical properties. The present work reports folate targeted hybrid lipo-polymeric nanoplexes for co-delivering DTX and miR-34a. These nanoplexes exhibited a mean size of 129.3 nm with complexation efficiency at an 8:1 N/P ratio. The obtained nanoplexes demonstrated higher entrapment efficiency of DTX (94.8%) with a sustained release profile up to 85% till 48 h. Further, an improved transfection efficiency in MDA-MB-231 and 4T1 breast cancer cells was observed with uptake primarily through lipid-raft and clathrin-mediated endocytosis. Further, nanoplexes showed improved cytotoxicity (~3.5-5 folds), apoptosis (~1.6-2.0 folds), and change in expression of apoptotic genes (~4-7 folds) compared to the free treatment group in breast cancer cells. In vivo systemic administration of FA-functionalized DTX and FAM-siRNA-loaded nanoplexes showed an improved area under the curve (AUC) as well as circulation half-life compared to free DTX and naked FAM-labelled siRNA. Acute toxicity studies of the cationic polymer showed no toxicity at a dose equivalent to 10 mg/kg based on the hematological, biochemical, and histopathological examination.

Exosomes as natural delivery carriers for programmable therapeutic nucleic acid nanoparticles (NANPs)

With recent advances in nanotechnology and therapeutic nucleic acids (TNAs), various nucleic acid nanoparticles (NANPs) have demonstrated great promise in diagnostics and therapeutics. However, the full realization of NANPs' potential necessitates the development of a safe, efficient, biocompatible, stable, tissue-specific, and non-immunogenic delivery system. Exosomes, the smallest extracellular vesicles and an endogenous source of nanocarriers, offer these advantages while avoiding complications associated with manufactured agents. The lipid membranes of exosomes surround a hydrophilic core, allowing for the simultaneous incorporation of hydrophobic and hydrophilic drugs, nucleic acids, and proteins. Additional capabilities for post-isolation exosome surface modifications with imaging agents, targeting ligands, and covalent linkages also pave the way for their diverse biomedical applications. This review focuses on exosomes: their biogenesis, intracellular trafficking, transportation capacities, and applications with emphasis on the delivery of TNAs and programmable NANPs. We also highlight some of the current challenges and discuss opportunities related to the development of therapeutic exosome-based formulations and their clinical translation.

Improving regorafenib's organ target precision via nano-assembly to change its delivery mode abolishes chemoresistance and liver metastasis of colorectal cancer

Distant metastases and chemotherapy repellency are the key causes of colorectal cancer (CRC)-related mortality. Regorafenib, an oral multi-kinase inhibitor approved for treating advanced CRC with distant metastases and/or chemo-resistance, however only improves median overall survival by 1.4 months. Such limited therapeutic effect is likely due to the low bioavailability of orally administered hydrophobic regorafenib. A regorafenib nanodrug is fabricated by one-step self-assembly with a clinically often-used fluorescent agent (indocyanine green) for overcoming regorafenib's limitations, towards improving regorafenib's therapeutic efficacy in advanced CRC. This nanodrug (nanoRF) was characterized, and its antitumor effects were assessed in three preclinical CRC models. NanoRF converts regorafenib's delivery approach from oral to intravenous with a significantly high encapsulation efficacy of regorafenib (96%) and a long-time colloidal stability. Nanodrug (nanoRF) markedly prolongs regorafenib's blood circulation by halving clearance rate, and enhances regorafenib's tumor accumulation. Across three preclinical CRC models (xenografted tumor, chemodrug-resistant xenografted tumor, and liver metastasis), nanoRF drastically enhances regorafenib's tumor inhibiting efficacy by 0.5-4 folds and effectively extends survival by 0.5-5 folds. This regorafenib nanodrug is a simple, safe, and efficient therapeutic nanodrug for treating advanced CRC with a ready-to-be-clinically-translated potential.

Delivery of Anti-microRNA-712 to Inflamed Endothelial Cells Using Poly(β-amino ester) Nanoparticles Conjugated with VCAM-1 Targeting Peptide

Endothelial cells (ECs) are an important target for therapy in a wide range of diseases, most notably atherosclerosis. Developing efficient nanoparticle (NP) systems that deliver RNA interference (RNAi) drugs specifically to dysfunctional ECs in vivo to modulate their gene expression remains a challenge. To date, several lipid-based NPs are developed and shown to deliver RNAi to ECs, but few of them are optimized to specifically target dysfunctional endothelium. Here, a novel, targeted poly(β-amino ester) (pBAE) NP is demonstrated. This pBAE NP is conjugated with VHPK peptides that target vascular cell adhesion molecule 1 protein, overexpressed on inflamed EC membranes. To test this approach, the novel NPs are used to deliver anti-microRNA-712 (anti-miR-712) specifically to inflamed ECs both in vitro and in vivo, reducing the high expression of pro-atherogenic miR-712. A single administration of anti-miR-712 using the VHPK-conjugated-pBAE NPs in mice significantly reduce miR-712 expression, while preventing the loss of its target gene, tissue inhibitor of metalloproteinase 3 (TIMP3) in inflamed endothelium. miR-712 and TIMP3 expression are unchanged in non-inflamed endothelium. This novel, targeted-delivery platform may be used to deliver RNA therapeutics specifically to dysfunctional endothelium for the treatment of vascular disease.

Cyanuric chloride as the basis for compositionally diverse lipids

Cyanuric chloride has been utilized in the development of new synthetic lipid compounds using two differing schemes. The resulting lipids, presented in this manuscript, were characterized and evaluated for their ability to form nanoparticles and subsequently tested for their utility in various biological applications, including gene delivery and immunization. Of the 12 lipids synthesized, 8 formed nanoparticles that remained stable, based on dynamic light scattering, for at least one month. The compounds were then assessed for their toxicity, and subsequently tested for their ability to encapsulate drugs, genes and peptides. While the compounds did not seem to encapsulate carboxyfluorescein, we demonstrate that these lipids are capable of plasmid delivery in vitro, and inducing antibody profiles similar to other hydrophobic anchors in liposomal peptide vaccines. This strategy for accessing diverse lipid compounds offers a way to easily optimize lipid-based therapeutics for research in an expedited manner.

Selective Anti-melanoma Effect of Phosphothioated Aptamer Encapsulated by Neutral Cytidinyl/Cationic Lipids

BC15-31 is a DNA aptamer that targets heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), which plays a crucial role in the process of pre-RNA maturation and is also essential for the rapid proliferation of tumor cells. In this research, we modified BC15-31 with a phosphorothioate (PS) backbone, LNA, and 2-O-MOE to enhance its stability and target affinity. In addition, a neutral cytidinyl lipid (DNCA) and a cationic lipid (CLD) were mixed to encapsulate modified aptamers with the aim of improving their cell permeability with low toxicity. Under the DNCA/CLD package, aptamers are mainly distributed in the nucleus. A modified sequence WW-24 showed an excellent selective anti-melanoma (A375 cells, ∼25 nM, 80%) activity, targeted to both hnRNP A1 and hnRNP A2/B1 found by the BLI experiment, and induced more early and late apoptosis in vitro, which also showed stronger antitumor effect and longer accumulation time in vivo. These results provide a new strategy for further clinical applications.

Identification of a potent ionizable lipid for efficient macrophage transfection and systemic anti-interleukin-1β siRNA delivery against acute liver failure

RNA interference (RNAi) therapy has great potential for treating inflammatory diseases. However, the development of potent carrier materials for delivering siRNA to macrophages is challenging. Herein, we design a set of ionizable lipid nanoparticles (LNPs) to screen and identify a potent carrier of siRNA for silencing an essential pro-inflammatory cytokine, interleukin-1β (IL-1β) in macrophages. The top performance LNP (114-LNP), containing ionizable lipid with spermine as an amine-head group, facilitated efficient siRNA internalization via multiple endocytosis pathways and achieved effective endosome escape in macrophages. The optimized LNP/siIL-1β achieved strong silencing of IL-1β in both activated Raw 264.7 cells and primary macrophages. Furthermore, systematic administration of 114-LNP/siIL-1β complexes could effectively inhibit IL-1β expression in an acute liver failure model and significantly attenuated hepatic inflammation and liver damage. These results suggest that the optimized ionizable lipid nanoparticle represents a promising platform for anti-inflammation therapies.

Effects of Surface Charge, PEGylation and Functionalization with Dipalmitoylphosphatidyldiglycerol on Liposome-Cell Interactions and Local Drug Delivery to Solid Tumors via Thermosensitive Liposomes

Purpose

Previous studies demonstrated the possibility of targeting tumor-angiogenic endothelial cells with positively charged nanocarriers, such as cationic liposomes. We investigated the active targeting potential of positively charged nanoparticles in combination with the heat-induced drug release function of thermosensitive liposomes (TSL). This novel dual-targeted approach via cationic TSL (CTSL) was thoroughly explored using either a novel synthetic phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphodiglycerol (DPPG₂) or a conventional polyethylene glycol (PEG) surface modification. Anionic particles containing either DPPG₂ or PEG were also included in the study to highlight difference in tumor enrichment driven by surface charge. With this study, we aim to provide a deep insight into the main differences between DPPG₂- and PEG-functionalized liposomes, focusing on the delivery of a well-known cytotoxic drug (doxorubicin; DOX) in combination with local hyperthermia (HT, 41–43°C).

Materials and Methods

DPPG₂- and PEG-based cationic TSLs (PG₂-CTSL/PEG-CTSL) were thoroughly analyzed for size, surface charge, and heat-triggered DOX release. Cancer cell targeting and DOX delivery was evaluated by FACS, fluorescence imaging, and HPLC. In vivo particle behavior was analyzed by assessing DOX biodistribution with local HT application in tumor-bearing animals.

Results

The absence of PEG in PG₂-CTSL promoted more efficient liposome–cell interactions, resulting in a higher DOX delivery and cancer cell toxicity compared with PEG-CTSL. By exploiting the dual-targeting function of CTSLs, we were able to selectively trigger DOX release in the intracellular compartment by HT. When tested in vivo, local HT promoted an increase in intratumoral DOX levels for all (C)TSLs tested, with DOX enrichment factors ranging from 3 to 14-fold depending on the type of formulation.

Conclusion

Cationic particles showed lower hemocompatibility than their anionic counterparts, which was partially mitigated when PEG was grafted on the liposome surface. DPPG₂-based anionic TSL showed optimal local drug delivery compared to all other formulations tested, demonstrating the potential advantages of using DPPG₂ lipid in designing liposomes for tumor-targeted applications.

mPEG2k-PCLx Polymeric Micelles Influence Pharmacokinetics and Hypoglycemic Efficacy of Metformin through Inhibition of Organic Cation Transporters in Rats

Increasing evidence has shown that nanocarriers have effects on several efflux drug transporters. To date, little is known about whether influx transporters are also modulated. Herein, we investigated the impact of amphiphilic polymer micelles on the uptake function of organic cation transporters (OCTs) and the influence on the pharmacokinetics and pharmacodynamics of metformin, a well-characterized substrate of OCTs. Five types of polymeric micelles (mPEG_2k-PCL_2k, mPEG_2k-PCL_3.5k, mPEG_2k-PCL_5k, mPEG_2k-PCL_7.5k, and mPEG_2k-PCL_10k) were prepared to evaluate the inhibition of hOCT1-3-overexpressing Madin-Darby canine kidney cells. The mPEG_2k-PCL_x micelles played an inhibitory role above the critical micelle concentration. The inhibitory potency could be ranked as mPEG_2k-PCL_2k > mPEG_2k-PCL_3.5k > mPEG_2k-PCL_5k > mPEG_2k-PCL_7.5k > mPEG_2k-PCL_10k, which negatively declined with the increase of molecular weight of the hydrophobic segment. The inhibitory effects of polymeric micelles on the hOCT1 isoform were the most pronounced, with the lowest IC₅₀ values ranging from 0.106 to 0.280 mg/mL. The mPEG_2k-PCL_2k micelles distinctly increased the plasma concentration of metformin and significantly decreased V_ss by 35.6% (p < 0.05) after seven consecutive treatments in rats, which was interrelated with the restrained metformin distribution in the liver and kidney. The uptake inhibition of micelles on hepatic and renal rOcts also diminished the glucose-lowering effect of metformin and fasting insulin levels in the oral glucose tolerance test. Consistent with the inhibitory effects, the mRNA and protein levels of rOct1 and rOct2 were decreased in the liver, kidney, and small intestine. The present study demonstrated that mPEG_2k-PCL_x micelles could inhibit the transport function of OCTs, indicating a potential risk of drug-drug interactions during concomitant medication of nanomedicine with organic cationic drugs.

Optimization of microbubble-based DNA vaccination with low-frequency ultrasound for enhanced cancer immunotherapy

Immunotherapy is an important cancer treatment strategy; nevertheless, the lack of robust immune cell infiltration in the tumor microenvironment remains a factor in limiting patient response rates. In vivo gene delivery protocols can amplify immune responses and sensitize tumors to immunotherapies, yet non-viral transfection methods often sacrifice transduction efficiency for improved safety tolerance. To improve transduction efficiency, we optimized a strategy employing low ultrasound transmission frequency-induced bubble oscillation to introduce plasmids into tumor cells. Differential centrifugation isolated size-specific microbubbles. The diameter of the small microbubble population was 1.27 ± 0.89 μm and that of larger population was 4.23 ± 2.27 μm. Upon in vitro insonation with the larger microbubble population, 29.7% of cancer cells were transfected with DNA plasmids, higher than that with smaller microbubbles (18.9%, P <0.05) or positive control treatments with a commercial transfection reagent (12%, P < 0.01). After 48 h, gene expression increased more than two-fold in tumors treated with large, as compared with small, microbubbles. Furthermore, the immune response, including tumor infiltration of CD8⁺ T cells and F4/80⁺ macrophages, was enhanced. We believe that this safe and efficacious method can improve preclinical procedures and outcomes for DNA vaccines in cancer immunotherapy in the future.

Liposome technologies towards colorectal cancer therapeutics

Colorectal cancer (CRC) is the third most common cancer and the fourth most common deadly cancer worldwide. After treatment with curative intent recurrence rates vary with staging 0-13% in Stage 1, 11-61% in S2 and 28-73% in Stage 3. The toxicity to healthy tissues from chemotherapy and radiotherapy and drug resistance severely affect the quality of life and cancer specific outcomes of CRC patients. To overcome some of these limitations, many efforts have been made to develop nanomaterial-based drug delivery systems. Among these nanocarriers, liposomes represented one of the most successful candidates in delivering targeted oncological treatment, improving safety profile and therapeutic efficacy of encapsulated drugs. In this review we will discuss liposome design with a particular focus on the targeting feature and triggering functions. We will also summarise the recent advances in liposomal delivery system for CRC treatment in both the preclinical and clinical studies. We will finally provide our perspectives on the liposome technology development for the future clinical translation. STATEMENT OF SIGNIFICANCE: Conventional treatments for colorectal cancer (CRC) severely affect the therapeutic effects for advanced patients. With the development of nanomedicines, liposomal delivery system appears to be one of the most promising nanocarriers for CRC treatment. In last three years several reviews in this area have been published focusing on the preclinical research and drug delivery function, which is a fairly narrow focus in the field of liposome technology for CRC therapy. Our review presented the most recent advances of the liposome technology (both clinical and preclinical applications) for CRC with strong potential for further clinical translation. We believe it will attract lots of attention from various audiences, including researchers, clinicians and the industry.

Membrane fusion and drug delivery with carbon nanotube porins

Drug delivery mitigates toxic side effects and poor pharmacokinetics of life-saving therapeutics and enhances treatment efficacy. However, direct cytoplasmic delivery of drugs and vaccines into cells has remained out of reach. We find that liposomes studded with 0.8-nm-wide carbon nanotube porins (CNTPs) function as efficient vehicles for direct cytoplasmic drug delivery by facilitating fusion of lipid membranes and complete mixing of the membrane material and vesicle interior content. Fusion kinetics data and coarse-grained molecular dynamics simulations reveal an unusual mechanism where CNTP dimers tether the vesicles, pull the membranes into proximity, and then fuse their outer and inner leaflets. Liposomes containing CNTPs in their membranes and loaded with an anticancer drug, doxorubicin, were effective in delivering the drug to cancer cells, killing up to 90% of them. Our results open an avenue for designing efficient drug delivery carriers compatible with a wide range of therapeutics.

Exploring the possible targeting strategies of liposomes against methicillin-resistant Staphylococcus aureus (MRSA)

Multi antibiotic-resistant bacterial infections are on the rise due to the overuse of antibiotics. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the pathogens listed under the category of serious threats where vancomycin remains the mainstay treatment despite the availability of various antibacterial agents. Recently, decreased susceptibility to vancomycin from clinical isolates of MRSA has been reported and has drawn worldwide attention as it is often difficult to overcome and leads to increased medical costs, mortality, and longer hospital stays. Development of antibiotic delivery systems is often necessary to improve bioavailability and biodistribution, in order to reduce antibiotic resistance and increase the lifespan of antibiotics. Liposome entrapment has been used as a method to allow higher drug dosing apart from reducing toxicity associated with drugs. The surface of the liposomes can also be designed and enhanced with drug-release properties, active targeting, and stealth effects to prevent recognition by the mononuclear phagocyte system, thus enhancing its circulation time. The present review aimed to highlight the possible targeting strategies of liposomes against MRSA bacteremia systemically while investigating the magnitude of this effect on the minimum inhibitory concentration level.

Substantial cell apoptosis provoked by naked PAMAM dendrimers in HER2-positive human breast cancer via JNK and ERK1/ERK2 signalling pathways

HER2-positive breast cancer is one of its most challenging subtypes, forming around 15-25% of the total cases. It is characterized by aggressive behavior and treatment resistance. On the other hand, poly (amidoamine) (PAMAM) dendrimers are widely used in drug delivery systems and gene transfection as carriers. PAMAMs can modulate gene expression and interfere with transactivation of the human epidermal growth factor receptor family members (HER1-4). Nevertheless, the outcome of PAMAMs on HER2-positive breast cancer remains unknown. Thus, in this study, we investigated the anti-cancer effects of different generations of PAMAM dendrimers (G₄ and G₆) and the outcome of their surface chemistries (cationic, neutral, and anionic) on HER2-positive breast cancer cell lines, SKBR3 and ZR75. Our data showed that PAMAM dendrimers, mainly cationic types, significantly reduce cell viability in a dose-dependent manner. More significantly, PAMAMs induce substantial cell apoptosis, accompanied by the up-regulation of apoptotic markers (Bax, Caspases-3, 8 and 9) in addition to down-regulation of Bcl-2. Moreover, our data pointed out that cationic PAMAMs inhibit colony formation compared to controls and other types of PAMAMs. The molecular pathway analysis of PAMAM exposed cells revealed that PAMAMs enhance JNK1/2/3 expression while blocking ERK1/2, in addition to EGFR1 (HER1) and HER2 activities, which could be the major molecular pathway behind these events. These observed effects were comparable to lapatinib treatment, a clinically used inhibitor of HER1 and 2 receptors phosphorylation. Our findings implicate that PAMAMs may possess important therapeutic effects against HER2-positive breast cancer via JNK1/2/3, ERK1/2, and HER1/2 signalling pathways.

Preclinical models and technologies to advance nanovaccine development

The remarkable success of targeted immunotherapies is revolutionizing cancer treatment. However, tumor heterogeneity and low immunogenicity, in addition to several tumor-associated immunosuppression mechanisms are among the major factors that have precluded the success of cancer vaccines as targeted cancer immunotherapies. The exciting outcomes obtained in patients upon the injection of tumor-specific antigens and adjuvants intratumorally, reinvigorated interest in the use of nanotechnology to foster the delivery of vaccines to address cancer unmet needs. Thus, bridging nano-based vaccine platform development and predicted clinical outcomes the selection of the proper preclinical model will be fundamental. Preclinical models have revealed promising outcomes for cancer vaccines. However, only few cases were associated with clinical responses. This review addresses the major challenges related to the translation of cancer nano-based vaccines to the clinic, discussing the requirements for ex vivo and in vivo models of cancer to ensure the translation of preclinical success to patients.

A comprehensive study on 2D, 3D and solid tumor environment to explore a multifunctional biogenic nanoconjugate

Emergence of nanotechnology created a drastic change in the field of cancer therapy due to their unique features in drug delivery and imaging. Polysaccharide based nanoparticles have received extensive attention in recent years as promising nanoparticle mediated drug delivery systems. Polysaccharides are endorsed with versatile merits including high drug encapsulation efficiency, efficient drug protection against chemical or enzymatic degradation, unique ability to create a controlled release and cellular internalization. In the current study, we have fabricated doxorubicin-loaded carboxymethylated PST001 coated iron oxide nanoparticles (DOX@CM-PST-IONPs) for better management of cancer. CM-PST coated iron oxide nanoparticles co-encapsulated with chemotherapeutic drug doxorubicin, can be utilized for targeted drug delivery. Biocompatible and non-toxic nanoconjugates was found to be effective in both 2-D and 3-D cell culture system with efficient cancer cell internalization. The bench-marked potential of CM-PIONPs to produce reactive oxygen species makes it a noticeable drug delivery system to compact neoplasia. These nanoconjugates can lay concrete on a better way for the elimination of cancer spheroids and tumor burden.

Cationic Nanoparticle-Based Cancer Vaccines

Cationic nanoparticles have been shown to be surprisingly effective as cancer vaccine vehicles in preclinical and clinical studies. Cationic nanoparticles deliver tumor-associated antigens to dendritic cells and induce immune activation, resulting in strong antigen-specific cellular immune responses, as shown for a wide variety of vaccine candidates. In this review, we discuss the relation between the cationic nature of nanoparticles and the efficacy of cancer immunotherapy. Multiple types of lipid- and polymer-based cationic nanoparticulate cancer vaccines with various antigen types (e.g., mRNA, DNA, peptides and proteins) and adjuvants are described. Furthermore, we focus on the types of cationic nanoparticles used for T-cell induction, especially in the context of therapeutic cancer vaccination. We discuss different cationic nanoparticulate vaccines, molecular mechanisms of adjuvanticity and biodistribution profiles upon administration via different routes. Finally, we discuss the perspectives of cationic nanoparticulate vaccines for improving immunotherapy of cancer.

A Simple and Quick Method for Loading Proteins in Extracellular Vesicles

Extracellular vesicles (EVs) mediate intercellular transport of biomolecular cargo in the body, making them promising delivery vehicles for bioactive compounds. Genetic engineering of producer cells has enabled encapsulation of therapeutic proteins in EVs. However, genetic engineering approaches can be expensive, time-consuming, and incompatible with certain EV sources, such as human plasma and bovine milk. The goal of this study was to develop a quick, versatile, and simple method for loading proteins in EVs post-isolation. Proteins, including CRISPR associated protein 9 (Cas9), were bound to cationic lipids that were further complexed with MDA-MB-231 cell-derived EVs through passive incubation. Size-exclusion chromatography was used to remove components that were not complexed with EVs. The ability of EVs to mediate intracellular delivery of proteins was compared to conventional methods, such as electroporation and commercial protein transfection reagents. The results indicate that EVs retain native features following protein-loading and obtain similar levels of intracellular protein delivery as conventional methods, but display less toxicity. This method opens up opportunities for rapid exploration of EVs for protein delivery.

Exploration and insights into the cellular internalization and intracellular fate of amphiphilic polymeric nanocarriers

The beneficial or deleterious effects of nanomedicines emerge from their complex interactions with intracellular pathways and their subcellular fate. Moreover, the dynamic nature of plasma membrane accounts for the movement of these nanocarriers within the cell towards different organelles thereby not only influencing their pharmacokinetic and pharmacodynamic properties but also bioavailability, therapeutic efficacy and toxicity. Therefore, an in-depth understanding of underlying parameters controlling nanocarrier endocytosis and intracellular fate is essential. In order to direct nanoparticles towards specific sub-cellular organelles the physicochemical attributes of nanocarriers can be manipulated. These include particle size, shape and surface charge/chemistry. Restricting the particle size of nanocarriers below 200 nm contributes to internalization via clathrin and caveolae mediated pathways. Similarly, a moderate negative surface potential confers endolysosomal escape and targeting towards mitochondria, endoplasmic reticulum (ER) and Golgi. This review aims to provide an insight into these physicochemical attributes of nanocarriers fabricated using amphiphilic graft copolymers affecting cellular internalization. Fundamental principles understood from experimental studies have been extrapolated to draw a general conclusion for the designing of optimized nanoparticulate drug delivery systems and enhanced intracellular uptake via specific endocytic pathway.

The pharmacology of plant virus nanoparticles

The application of nanoparticles for medical purposes has made enormous strides in providing new solutions to health problems. The observation that plant virus-based nanoparticles (VNPs) can be repurposed and engineered as smart bio-vehicles for targeted drug delivery and imaging has launched extensive research for improving the therapeutic and diagnostic management of various diseases. There is evidence that VNPs are promising high value nanocarriers with potential for translational development. This is mainly due to their unique features, encompassing structural uniformity, ease of manufacture and functionalization by means of expression, chemical biology and self-assembly. While the development pipeline is moving rapidly, with many reports focusing on engineering and manufacturing aspects to tailor the properties and efficacy of VNPs, fewer studies have focused on gaining insights into the nanotoxicity of this novel platform nanotechnology. Herein, we discuss the pharmacology of VNPs as a function of formulation and route of administration. VNPs are reviewed in the context of their application as therapeutic adjuvants or nanocarrier excipients to initiate, enhance, attenuate or impede the formulation's toxicity. The summary of the data however also underlines the need for meticulous VNP structure-nanotoxicity studies to improve our understanding of their in vivo fates and pharmacological profiles to pave the way for translation of VNP-based formulations into the clinical setting.

Lipid membrane-based therapeutics and diagnostics

Success rates in drug discovery are extremely low, and the imbalance between new drugs entering clinical research and their approval is steadily widening. Among the causes of the failure of new therapeutic agents are the lack of safety and insufficient efficacy. On the other hand, timely disease diagnosis may enable an early management of the disease, generally leading to better and less costly outcomes. Several strategies have been explored to overcome the barriers for drug development and facilitate diagnosis. Using lipid membranes as platforms for drug delivery or as biosensors are promising strategies, due to their biocompatibility and unique physicochemical properties. We examine some of the lipid membrane-based strategies for drug delivery and diagnostics, including their advantages and shortcomings. Regarding synthetic lipid membrane-based strategies for drug delivery, liposomes are the archetypic example of a successful approach, already with a long period of well-succeeded clinical application. The use of lipid membrane-based structures from biological sources as drug carriers, currently under clinical evaluation, is also discussed. These biomimetic strategies can enhance the in vivo lifetime of drug and delivery system by avoiding fast clearance, consequently increasing their therapeutic window. The strategies under development using lipid membranes for diagnostic purposes are also reviewed.

Biological and Physico-Chemical Characteristics of Arginine-Rich Peptide Gemini Surfactants with Lysine and Cystine Spacers

Ultrashort cationic lipopeptides (USCLs) and gemini cationic surfactants are classes of potent antimicrobials. Our recent study has shown that the branching and shortening of the fatty acids chains with the simultaneous addition of a hydrophobic N-terminal amino acid in USCLs result in compounds with enhanced selectivity. Here, this approach was introduced into arginine-rich gemini cationic surfactants. l-cystine diamide and l-lysine amide linkers were used as spacers. Antimicrobial activity against planktonic and biofilm cultures of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) strains and Candida sp. as well as hemolytic and cytotoxic activities were examined. Moreover, antimicrobial activity in the presence of human serum and the ability to form micelles were evaluated. Membrane permeabilization study, serum stability assay, and molecular dynamics were performed. Generally, critical aggregation concentration was linearly correlated with hydrophobicity. Gemini surfactants were more active than the parent USCLs, and they turned out to be selective antimicrobial agents with relatively low hemolytic and cytotoxic activities. Geminis with the l-cystine diamide spacer seem to be less cytotoxic than their l-lysine amide counterparts, but they exhibited lower antibiofilm and antimicrobial activities in serum. In some cases, geminis with branched fatty acid chains and N-terminal hydrophobic amino acid resides exhibited enhanced selectivity to pathogens over human cells.

Recent Advancements in Nanomedicine for 'Cold' Tumor Immunotherapy

Although current anticancer immunotherapies using immune checkpoint inhibitors (ICIs) have been reported with a high clinical success rate, numerous patients still bear 'cold' tumors with insufficient T cell infiltration and low immunogenicity, responding poorly to ICI therapy. Considering the advancements in precision medicine, in-depth mechanism studies on the tumor immune microenvironment (TIME) among cold tumors are required to improve the treatment for these patients. Nanomedicine has emerged as a promising drug delivery system in anticancer immunotherapy, activates immune function, modulates the TIME, and has been applied in combination with other anticancer therapeutic strategies. This review initially summarizes the mechanisms underlying immunosuppressive TIME in cold tumors and addresses the recent advancements in nanotechnology for cold TIME reversal-based therapies, as well as a brief talk about the feasibility of clinical translation.

LipoParticles: Lipid-Coated PLA Nanoparticles Enhanced In Vitro mRNA Transfection Compared to Liposomes

The approval of two mRNA vaccines as urgent prophylactic treatments against Covid-19 made them a realistic alternative to conventional vaccination methods. However, naked mRNA is rapidly degraded by the body and cannot effectively penetrate cells. Vectors capable of addressing these issues while allowing endosomal escape are therefore needed. To date, the most widely used vectors for this purpose have been lipid-based vectors. Thus, we have designed an innovative vector called LipoParticles (LP) consisting of poly(lactic) acid (PLA) nanoparticles coated with a 15/85 mol/mol DSPC/DOTAP lipid membrane. An in vitro investigation was carried out to examine whether the incorporation of a solid core offered added value compared to liposomes alone. To that end, a formulation strategy that we have named particulate layer-by-layer (pLbL) was used. This method permitted the adsorption of nucleic acids on the surface of LP (mainly by means of electrostatic interactions through the addition of LAH4-L1 peptide), allowing both cellular penetration and endosomal escape. After a thorough characterization of size, size distribution, and surface charge- and a complexation assessment of each vector-their transfection capacity and cytotoxicity (on antigenic presenting cells, namely DC2.4, and epithelial HeLa cells) were compared. LP have been shown to be significantly better transfecting agents than liposomes through pLbL formulation on both HeLa and DC 2.4 cells. These data illustrate the added value of a solid particulate core inside a lipid membrane, which is expected to rigidify the final assemblies and makes them less prone to early loss of mRNA. In addition, this assembly promoted not only efficient delivery of mRNA, but also of plasmid DNA, making it a versatile nucleic acid carrier that could be used for various vaccine applications. Finally, if the addition of the LAH4-L1 peptide systematically leads to toxicity of the pLbL formulation on DC 2.4 cells, the optimization of the nucleic acid/LAH4-L1 peptide mass ratio becomes an interesting strategy-essentially reducing the peptide intake to limit its cytotoxicity while maintaining a relevant transfection efficiency.

Design strategies and evolving role of biomaterial assisted treatment of osteosarcoma

Osteosarcoma is the most commonly diagnosed form of bone cancer. It is characterized by a high risk of developing lung metastasis as the disease progresses. Standard treatment includes combination of surgical intervention, chemotherapy and radiotherapy. However, the non-specificity of potent chemotherapeutic agents often leads to major side effects. In this review, we discuss the role of various classes of biomaterials, including both organic as well as inorganic in realizing the local and systemic delivery of therapeutic agents like drugs, radioisotopes and even gene silencing agents to treat osteosarcoma. Biomaterial assisted unconventional therapies such as targeted therapy, nanotherapy, magnetic hyperthermia, gene therapy, photothermal and photodynamic therapies are also being explored. A wide variety of biomaterials including lipids, carbon-based materials, polymers, silica, bioactive glass, hydroxyapatite and metals are designed as delivery systems with the desired loading efficiency, release profile, and on-demand delivery. Among others, liposomal carriers have attracted a great deal of attention due to their capability to encapsulate both hydrophobic and hydrophilic drugs. Polymeric systems have high drug loading efficiency and stability and can even be tailored to achieve desired size and physiochemical properties. Carbon-based systems can also be seen as an upcoming class of therapeutics with great potential in treating different types of cancer. Inorganic materials like silica nanoparticles have high drug payload owing to their mesoporous structure. On the other hand, ceramic materials like bioactive glass and hydroxyapatite not only act as excellent delivery vectors but also participate in osteo-regeneration activity. These multifunctional biomaterials are also being investigated for their theranostic abilities to monitor cancer ablation. This review systematically discusses the vast landscape of biomaterials along with their challenges and respective opportunities for osteosarcoma therapy.

Delivery of siRNA to Endothelial Cells In Vivo Using Lysine/Histidine Oligopeptide-Modified Poly(β-amino ester) Nanoparticles

PURPOSE

Endothelial cell (EC) dysfunction underlies the pathology of multiple disease conditions including cardiovascular and pulmonary diseases. Dysfunctional ECs have a distinctive gene expression profile compared to healthy ECs. RNAi therapy is a powerful therapeutic approach that can be used to silence multiple genes of interests simultaneously. However, the delivery of RNAi to ECs in vivo continues to be a major challenge. Here, we optimized a polymer formulation based on poly(β-amino ester)s (pBAEs) to deliver siRNA to vascular ECs.

METHODS

We developed a library of bioinspired oligopeptide-modified pBAE nanoparticles (NPs) with different physicochemical proprieties and screened them for cellular uptake and efficacy of RNAi delivery in vitro using ECs, vascular smooth muscle cells, and THP-1 monocytes. From the screening, the lysine-/histidine-oligopeptide modified pBAE (C6-KH) NP was selected and further tested ex vivo using mouse aorta and in mice to determine efficiency of siRNA delivery in vivo.

RESULTS

The in vitro screening study showed that C6-KH was most efficient in delivering siRNA to ECs. Ex vivo study showed that C6-KH nanoparticles containing siRNAs accumulated in the endothelial layer of mouse aortas. In vivo study showed that C6-KH nanoparticles carrying siICAM2 injected via tail-vein in mice significantly reduced ICAM2 level in the artery endothelium (55%), lung (52%), and kidney (31%), but not in the liver, heart, and thymus, indicating a tissue-specific delivery pattern.

CONCLUSIONS

We demonstrate that C6-KH pBAE can used for delivery of siRNAs to the artery endothelium and lung, while minimizing potential side or toxic effects in the liver and heart.

A Triple Role for a Bilayer: Using Nanoliposomes to Cross and Protect Cellular Membranes

Thanks in large part to the seminal work of Steve White and his colleagues, we appreciate the "ordered complexity" of the lipid bilayer and how it impacts the incorporation of integral membrane proteins as well as more peripherally associated proteins. Steve's work also provides a vital foundation to tackle another challenge: cytotoxic oligomeric complexes which accumulate in various neurodegenerative diseases. These oligomers have a relatively fluid structure and interact with many different proteins in the cell, but their main target is thought to be the phospholipid membrane, either the plasma membrane or internal organelles such as the mitochondria. This fascinating encounter between two essentially fluid phases generates a more disordered membrane, and presumably promotes uncontrolled transport of small metal ions across the membrane barrier. Happily, this unwanted interaction may be suppressed by mobilizing the phospholipid bilayer into its own defense. Extruded nanolipoparticles (NLPs) consisting of DPPC lipids, cholesterol and PEG2000 are excellent vehicles to take up small "oligomer-bashing" hydrophobic molecules such as baicalein and transport them with increased half-life in the plasma and with markedly more efficient crossing of the blood-brain barrier. Thus the bilayer has a triple role in this account: a safe space for a reactive hydrophobic small molecule, a barrier to cross to deliver a drug payload and a target to protect against oligomer attacks. NLPs containing small hydrophobic molecules show great promise in combating neurodegenerative diseases in animal models and may serve as an example of the White approach: applying robust physical-chemical principles to deal with biological problems involving phospholipid membranes.

Preparation and Biological Property Evaluation of Novel Cationic Lipid-Based Liposomes for Efficient Gene Delivery

Novel cationic lipid-based liposomes prepared using an amphiphilic cationic lipid material, N,N-dimethyl-(N',N'-di-stearoyl-1-ethyl)1,3-diaminopropane (DMSP), have been proposed to enhance the transfection of nucleic acids. Herein, we designed and investigated liposomes prepared using DMSP, soybean phosphatidylcholine, and cholesterol. This novel gene vector has high gene loading capabilities and excellent protection against nuclease degradation. An in vitro study showed that the liposomes had lower toxicity and superior cellular uptake and transfection efficiency compared with Lipofectamine 2000. An endosomal escape study revealed that the liposomes demonstrated high endosomal escape and released their genetic payload in the cytoplasm efficiently. Mechanistic studies indicated that the liposome/nucleic acid complexes entered cells through energy-dependent endocytosis that was mediated by fossa proteins. These results suggest that such cationic lipid-based liposome vectors have potential for clinical gene delivery.

Intracerebral Injection of Graphene Oxide Nanosheets Mitigates Microglial Activation Without Inducing Acute Neurotoxicity: A Pilot Comparison to Other Nanomaterials

Carbon-based nanomaterials (CNMs) are being explored for neurological applications. However, systematic in vivo studies investigating the effects of CNM nanocarriers in the brain and how brain cells respond to such nanomaterials are scarce. To address this, functionalized multiwalled carbon nanotubes and graphene oxide (GO) sheets are injected in mice brain and compared with charged liposomes. The induction of acute neuroinflammatory and neurotoxic effects locally and in brain structures distant from the injection site are assessed up to 1 week postadministration. While significant neuronal cell loss and sustained microglial cell activation are observed after injection of cationic liposomes, none of the tested CNMs induces either neurodegeneration or microglial activation. Among the candidate nanocarriers tested, GO sheets appear to elicit the least deleterious neuroinflammatory profile. At molecular level, GO induces moderate activation of proinflammatory markers compared to vehicle control. At histological level, brain response to GO is lower than after vehicle control injection, suggesting some capacity for GO to reduce the impact of stereotactic injection on brain. While these findings are encouraging and valuable in the selection and design of nanomaterial-based brain delivery systems, they warrant further investigations to better understand the mechanisms underlying GO immunomodulatory properties in brain.

Treating brain diseases using systemic parenterally-administered protein therapeutics: Dysfunction of the brain barriers and potential strategies

The parenteral administration of protein therapeutics is increasingly gaining importance for the treatment of human diseases. However, the presence of practically impermeable blood-brain barriers greatly restricts access of such pharmaceutics to the brain. Treating brain disorders with proteins thus remains a great challenge, and the slow clinical translation of these therapeutics may be largely ascribed to the lack of appropriate brain delivery system. Exploring new approaches to deliver proteins to the brain by circumventing physiological barriers is thus of great interest. Moreover, parallel advances in the molecular neurosciences are important for better characterizing blood-brain interfaces, particularly under different pathological conditions (e.g., stroke, multiple sclerosis, Parkinson's disease, and Alzheimer's disease). This review presents the current state of knowledge of the structure and the function of the main physiological barriers of the brain, the mechanisms of transport across these interfaces, as well as alterations to these concomitant with brain disorders. Further, the different strategies to promote protein delivery into the brain are presented, including the use of molecular Trojan horses, the formulation of nanosystems conjugated/loaded with proteins, protein-engineering technologies, the conjugation of proteins to polymers, and the modulation of intercellular junctions. Additionally, therapeutic approaches for brain diseases that do not involve targeting to the brain are presented (i.e., sink and scavenging mechanisms).