The role of dendritic cells in cancer immunity and therapeutic strategies

Dendritic cells (DCs) are asserted as the most potent antigen-presenting cells (APCs) that orchestrate both innate and adaptive immunity, being extremely effective in the induction of robust anti-cancer T cell responses. Hence, the modulation of DCs function represents an attractive target for improving cancer immunotherapy efficacy. A better understanding of the immunobiology of DCs, the interaction among DCs, immune effector cells and tumor cells in tumor microenvironment (TME) and the latest advances in biomedical engineering technology would be required for the design of optimal DC-based immunotherapy. In this review, we focus on elaborating the immunobiology of DCs in healthy and cancer environments, the recent advances in the development of enhancing endogenous DCs immunocompetence via immunomodulators as well as DC-based vaccines. The rapidly developing field of applying nanotechnology to improve DC-based immunotherapy is also highlighted.

Aloe vera peel-derived nanovesicles display anti-inflammatory properties and prevent myofibroblast differentiation

BACKGROUND

Aloe vera (AV) is a medicinal plant, most known for its beneficial effects on a variety of skin conditions. Its known active compounds include carbohydrates and flavonoids such as quercetin and kaempferol, among others. In the past decade, plant nanovesicles (NVs) have gained considerable interest as interkingdom communicators, presenting an opportunity for clinical standardization of natural products. In this study, we aimed to assess the potential of AVpNVs for the treatment of burn wounds.

METHODS

AVpNVs were isolated and characterized regarding vesicle yield (nanoparticle tracking analysis) and structure (transmission electron microscopy and atomic force microscopy), as well as their protein content with proteomics. We assessed key characteristics for treating burn wounds in vitro, such as the anti-inflammatory potential in LPS-stimulated macrophages and keratinocytes, and the effect of AVpNVs on myofibroblast differentiation and contraction.

KEY FINDINGS

AVpNVs presented a homogenous NV population, vesicular shape, and NV-associated protein markers. AVpNVs significantly decreased the secretion of pro-inflammatory cytokines TNFα, IL-1β, and IL-6. Furthermore, AVpNVs inhibited myofibroblast differentiation and significantly decreased their contractile potential in collagen matrices. Observed effects were linked to proteins identified in the isolates through proteomics analysis.

CONCLUSION

AVpNVs displayed characteristics as an inflammatory modulator, while simultaneously diminishing myofibroblast differentiation and contraction. Novel strategies for burn wound treatment seek to decrease scarring on a cellular and molecular level in the early stages of wound healing, which makes AVpNVs a promising candidate for future plant-vesicle-based treatments.

Shrinking the battlefield in cancer therapy: Nanotechnology against cancer stem cells

Cancer remains one of the leading causes of mortality worldwide, presenting a significant healthcare challenge owing to the limited efficacy of current treatments. The application of nanotechnology in cancer treatment leverages the unique optical, magnetic, and electrical attributes of nanomaterials to engineer innovative, targeted therapies. Specifically, manipulating nanomaterials allows for enhanced drug loading efficiency, improved bioavailability, and targeted delivery systems, reducing the non-specific cytotoxic effects characteristic of conventional chemotherapies. Furthermore, recent advances in nanotechnology have demonstrated encouraging results in specifically targeting CSCs, a key development considering the role of these cells in disease recurrence and resistance to treatment. Despite these breakthroughs, the clinical approval rates of nano-drugs have not kept pace with research advances, pointing to existing obstacles that must be addressed. In conclusion, nanotechnology presents a novel, powerful tool in the fight against cancer, particularly in targeting the elusive and treatment-resistant CSCs. This comprehensive review delves into the intricacies of nanotherapy, explicitly targeting cancer stem cells, their markers, and associated signaling pathways.

Intrinsically bioactive and biomimetic nanoparticle-derived therapies alleviate asthma by regulating multiple pathological cells

Asthma is a serious global public health concern. Airway neutrophilic inflammation is closely related to severe asthma, for which effective and safe therapies remain to be developed. Here we report nanotherapies capable of simultaneously regulating multiple target cells relevant to the pathogenesis of neutrophilic asthma. A nanotherapy LaCD NP based on a cyclic oligosaccharide-derived bioactive material was engineered. LaCD NP effectively accumulated in the injured lungs of asthmatic mice and mainly distributed in neutrophils, macrophages, and airway epithelial cells after intravenous or inhalation delivery, thereby ameliorating asthmatic symptoms and attenuating pulmonary neutrophilic inflammation as well as reducing airway hyperresponsiveness, remodeling, and mucus production. Surface engineering via neutrophil cell membrane further enhanced targeting and therapeutic effects of LaCD NP. Mechanistically, LaCD NP can inhibit the recruitment and activation of neutrophils, especially reducing the neutrophil extracellular traps formation and NLRP3 inflammasome activation in neutrophils. Also, LaCD NP can suppress macrophage-mediated pro-inflammatory responses and prevent airway epithelial cell death and smooth muscle cell proliferation, by mitigating neutrophilic inflammation and its direct effects on relevant cells. Importantly, LaCD NP showed good safety performance. Consequently, LaCD-derived multi-bioactive nanotherapies are promising for effective treatment of neutrophilic asthma and other neutrophil-associated diseases.

A Novel 3DNA® Nanocarrier effectively delivers payloads to pancreatic tumors

INTRODUCTION

Standard-of-care systemic chemotherapies for pancreatic ductal adenocarcinoma (PDAC) currently have limited clinical benefits, in addition to causing adverse side effects in many patients. One factor known to contribute to the poor chemotherapy response is the poor drug diffusion into PDAC tumors. Novel treatment methods are therefore drastically needed to improve targeted delivery of treatments. Here, we evaluated the efficacy of the 3DNA® Nanocarrier (3DNA) platform to direct delivery of therapeutics to PDAC tumors in vivo.

MATERIALS AND METHODS

A panel of PDAC cell lines and a patient tissue microarray were screened for established tumor-specific proteins to identify targeting moieties for active targeting of the 3DNA. NRG mice with or without orthotopic MIA PaCa-2-luciferase PDAC tumors were treated intraperitoneally with 100 μl of fluorescently labeled 3DNA.

RESULTS

Folic acid and transferrin receptors were significantly elevated in PDAC compared to normal pancreas. Accordingly, both folic acid- and transferrin-conjugated 3DNA treatments significantly increased delivery of 3DNA specifically to tumors in comparison to unconjugated 3DNA treatment. In the absence of tumors, there was an increased clearance of both folic acid-conjugated 3DNA and unconjugated 3DNA, compared to the clearance rate in tumor-bearing mice. Lastly, delivery of siLuciferase by folic acid-conjugated 3DNA in an orthotopic model of luciferase-expressing PDAC showed significant and prolonged suppression of luciferase protein expression and activity.

CONCLUSION

Our study progresses the 3DNA technology as a reliable and effective treatment delivery platform for targeted therapeutic approaches in PDAC.

Targeting Tyrosinase in Hyperpigmentation: Current Status, Limitations and Future Promises

Hyperpigmentation is a common and distressing dermatologic condition. Since tyrosinase (TYR) plays an essential role in melanogenesis, its inhibition is considered a logical approach along with other therapeutic methods to prevent the accumulation of melanin in the skin. Thus, TYR inhibitors are a tempting target as the medicinal and cosmetic active agents of hyperpigmentation disorder. Among TYR inhibitors, hydroquinone is a traditional lightening agent that is commonly used in clinical practice. However, despite good efficacy, prolonged use of hydroquinone is associated with side effects. To overcome these shortcomings, new approaches in targeting TYR and treating hyperpigmentation are desperately requiredessentialneeded. In line with this purpose, several non-hydroquinone lightening agents have been developed and suggested as hydroquinone alternatives. In addition to traditional approaches, nanomedicine and nanotheranostic platforms have been recently proposed in the treatment of hyperpigmentation. In this review, we discuss the available strategies for the management of hyperpigmentation with a focus on TYR inhibition. In addition, alternative treatment options to hydroquinone are discussed. Finally, we present nano-based strategies to improve the therapeutic effect of drugs prescribed to patients with skin disorders.

Pathologically triggered in situ aggregation of nanoparticles for inflammation-targeting amplification and therapeutic potentiation

Uncontrolled and persistent inflammation is closely related to numerous acute and chronic diseases. However, effective targeting delivery systems remain to be developed for precision therapy of inflammatory diseases. Herein we report a novel strategy for engineering inflammation-accumulation nanoparticles via phenolic functionalization. Different phenol-functionalized nanoparticles were first developed, which can undergo in situ aggregation upon triggering by the inflammatory/oxidative microenvironment. Phenolic compound-decorated poly (lactide-co-glycolide) nanoparticles, in particular tyramine (Tyr)-coated nanoparticles, showed significantly enhanced accumulation at inflammatory sites in mouse models of colitis, acute liver injury, and acute lung injury, mainly resulting from in situ cross-linking and tissue anchoring of nanoparticles triggered by local myeloperoxidase and reactive oxygen species. By combining a cyclodextrin-derived bioactive material with Tyr decoration, a multifunctional nanotherapy (TTN) was further developed, which displayed enhanced cellular uptake, anti-inflammatory activities, and inflammatory tissue accumulation, thereby affording amplified therapeutic effects in mice with colitis or acute liver injury. Moreover, TTN can serve as a bioactive and inflammation-targeting nanoplatform for site-specifically delivering a therapeutic peptide to the inflamed colon post oral administration, leading to considerably potentiated in vivo efficacies. Preliminary studies also revealed good safety of orally delivered TTN. Consequently, Tyr-based functionalization is promising for inflammation targeting amplification and therapeutic potentiation of nanotherapies.

Photonic and magnetic materials for on-demand local drug delivery

Nanomedicine has been considered a promising tool for biomedical research and clinical practice in the 21st century because of the great impact nanomaterials could have on human health. The generation of new smart nanomaterials, which enable time- and space-controlled drug delivery, improve the limitations of conventional treatments, such as non-specific targeting, poor biodistribution and permeability. These smart nanomaterials can respond to internal biological stimuli (pH, enzyme expression and redox potential) and/or external stimuli (such as temperature, ultrasound, magnetic field and light) to further the precision of therapies. To this end, photonic and magnetic nanoparticles, such as gold, silver and iron oxide, have been used to increase sensitivity and responsiveness to external stimuli. In this review, we aim to report the main and most recent systems that involve photonic or magnetic nanomaterials for external stimulus-responsive drug release. The uniqueness of this review lies in highlighting the versatility of integrating these materials within different carriers. This leads to enhanced performance in terms of in vitro and in vivo efficacy, stability and toxicity. We also point out the current regulatory challenges for the translation of these systems from the bench to the bedside, as well as the yet unresolved matter regarding the standardization of these materials.

Targeted drug delivery to the retinal pigment epithelium: Untapped therapeutic potential for retinal diseases

The retinal pigment epithelium (RPE) plays a crucial part in sight-threatening diseases. In this review, we shed light on the pivotal implication of the RPE in age-related macular degeneration, diabetic retinopathy and retinopathy of prematurity; and explain why a paradigm shift toward targeted RPE therapy is needed to efficiently fight these retinal diseases. We provide guidance for the development of RPE-specific nanotherapeutics by giving a comprehensive overview of the possibilities and challenges of drug delivery to the RPE and highlight successful nanotherapeutic approaches targeting the RPE.

Nanotherapies for sepsis by regulating inflammatory signals and reactive oxygen and nitrogen species: New insight for treating COVID-19

SARS-CoV-2 has caused up to 127 million cases of COVID-19. Approximately 5% of COVID-19 patients develop severe illness, and approximately 40% of those with severe illness eventually die, corresponding to more than 2.78 million people. The pathological characteristics of COVID-19 resemble typical sepsis, and severe COVID-19 has been identified as viral sepsis. Progress in sepsis research is important for improving the clinical care of these patients. Recent advances in understanding the pathogenesis of sepsis have led to the view that an uncontrolled inflammatory response and oxidative stress are core factors. However, in the traditional treatment of sepsis, it is difficult to achieve a balance between the inflammation, pathogens (viruses, bacteria, and fungi), and patient tolerance, resulting in high mortality of patients with sepsis. In recent years, nanomaterials mediating reactive oxygen and nitrogen species (RONS) and the inflammatory response have shown previously unattainable therapeutic effects on sepsis. Despite these advantages, RONS and inflammatory response-based nanomaterials have yet to be extensively adopted as sepsis therapy. To the best of our knowledge, no review has yet discussed the pathogenesis of sepsis and the application of nanomaterials. To help bridge this gap, we discuss the pathogenesis of sepsis related to inflammation and the overproduction RONS, which activate pathogen-associated molecular pattern (PAMP)-pattern recognition receptor (PRR) and damage-associated molecular pattern (DAMP)-PRR signaling pathways. We also summarize the application of nanomaterials in the treatment of sepsis. As highlighted here, this strategy could synergistically improve the therapeutic efficacy against both RONS and inflammation in sepsis and may prolong survival. Current challenges and future developments for sepsis treatment are also summarized.

Glioblastoma multiforme (GBM): An overview of current therapies and mechanisms of resistance

Glioblastoma multiforme (GBM) is a WHO grade IV glioma and the most common malignant, primary brain tumor with a 5-year survival of 7.2%. Its highly infiltrative nature, genetic heterogeneity, and protection by the blood brain barrier (BBB) have posed great treatment challenges. The standard treatment for GBMs is surgical resection followed by chemoradiotherapy. The robust DNA repair and self-renewing capabilities of glioblastoma cells and glioma initiating cells (GICs), respectively, promote resistance against all current treatment modalities. Thus, durable GBM management will require the invention of innovative treatment strategies. In this review, we will describe biological and molecular targets for GBM therapy, the current status of pharmacologic therapy, prominent mechanisms of resistance, and new treatment approaches. To date, medical imaging is primarily used to determine the location, size and macroscopic morphology of GBM before, during, and after therapy. In the future, molecular and cellular imaging approaches will more dynamically monitor the expression of molecular targets and/or immune responses in the tumor, thereby enabling more immediate adaptation of tumor-tailored, targeted therapies.

Rheumatoid arthritis treatment using hydroxychloroquine and methotrexate co-loaded nanomicelles: In vivo results

Rheumatoid arthritis (RA) is the most common inflammatory rheumatic disease, affecting almost 1% of the world population. It is a long-lasting autoimmune disease, which mainly affects the joints causing inflammation and swelling of the synovial joint. RA has a significant impact on the ability to perform daily activities including simple work and household chores. Nonetheless, due to the long periods of pain and the continuous use of anti-inflammatory drugs, RA can debilitate the quality of life and increases mortality. Current therapeutic approaches to treat RA aim to achieve prolonged activity and early and persistent remission of the disease, with the gradual adoption of different drugs available. In this study, we developed a novel hydroxychloroquine and methotrexate co-loaded Pluronic® F-127 nanomicelle and evaluated its therapeutic effects against RA. Our results showed that drug-loaded nanomicelles were capable of modulating the inflammatory process of RA and reducing osteoclastogenesis, edema, and cell migration to the joint. Overall, compared to the free drugs, the drug-loaded nanomicelles showed a 2-fold higher therapeutic effect.

Nanotechnology in reproductive medicine: Opportunities for clinical translation

In recent years, nanotechnology has revolutionized global healthcare and has been predicted to exert a remarkable effect on clinical medicine. In this context, the clinical use of nanomaterials for cancer diagnosis, fertility preservation, and the management of infertility and other pathologies linked to pubertal development, menopause, sexually transmitted infections, and HIV (human immunodeficiency virus) has substantial promise to fill the existing lacunae in reproductive healthcare. Of late, a number of clinical trials involving the use of nanoparticles for the early detection of reproductive tract infections and cancers, targeted drug delivery, and cellular therapeutics have been conducted. However, most of these trials of nanoengineering are still at a nascent stage, and better synergy between pharmaceutics, chemistry, and cutting-edge molecular sciences is needed for effective translation of these interventions from bench to bedside. To bridge the gap between translational outcome and product development, strategic partnerships with the insight and ability to anticipate challenges, as well as an in-depth understanding of the molecular pathways involved, are highly essential. Such amalgamations would overcome the regulatory gauntlet and technical hurdles, thereby facilitating the effective clinical translation of these nano-based tools and technologies. The present review comprehensively focuses on emerging applications of nanotechnology, which holds enormous promise for improved therapeutics and early diagnosis of various human reproductive tract diseases and conditions.

Enhancement of single-walled carbon nanotube accumulation in glioma cells exposed to low-strength electric field: Promising approach in cancer nanotherapy

The objective of the study is to determine the patterns of regulation of single-walled carbon nanotube accumulation, distribution, and agglomeration in glioma cells exposed to an external electric field. C6 glioma cells were treated with 5 μg/ml DNA wrapped single-walled carbon nanotubes and exposed to bi-phasic electric pulses (6.6 V/m, 200 Hz, pulse duration 1 ms). Nanotube accumulation was determined by Raman microspectroscopy and their intracellular local concentration was evaluated using the G-band intensity in Raman spectra of single-walled carbon nanotubes. It was revealed that the low-frequency and low-strength electric field stimulation of glioma cells exposed to single-walled carbon nanotubes led to facilitation and, thus, to amplification of nanotube accumulation inside the cells. The number of nanotubes in intracellular agglomerates increased from (28.8 ± 13.1) un./agglom. and (84.0 ± 28.7) un./agglom. in control samples to (60.6 ± 21.4) un./agglom. and (184.2 ± 53.4) un./agglom. for 1 h and 2 h stimulation, respectively. Thus, the tumor exposure to an external electric field makes it possible to more effectively regulate the accumulation and distribution of carbon nanotubes inside glioma cells allowing to reduce the applied therapeutic doses of carbon nanomaterial delivered anticancer drugs.

Targeting the blood-nerve barrier for the management of immune-mediated peripheral neuropathies

Healthy peripheral nerves encounter, with increased frequency, numerous chemical, biological, and biomechanical forces. Over time and with increasing age, these forces collectively contribute to the pathophysiology of a spectrum of traumatic, metabolic, and/or immune-mediated peripheral nerve disorders. The blood-nerve barrier (BNB) serves as a critical first-line defense against chemical and biologic insults while biomechanical forces are continuously buffered by a dense array of longitudinally orientated epineural collagen fibers exhibiting high-tensile strength. As emphasized throughout this Experimental Neurology Special Issue, the BNB is best characterized as a functionally dynamic multicellular vascular unit comprised of not only highly specialized endoneurial endothelial cells, but also associated perineurial cells, pericytes, Schwann cells, basement membrane, and invested axons. The composition of the BNB, while anatomically distinct, is not functionally dissimilar to that of the well characterized neurovascular unit of the central nervous system. While the BNB lacks a glial limitans and an astrocytic endfoot layer, the primary function of both vascular units is to establish, maintain, and protect an optimal endoneurial (PNS) or interstitial (CNS) fluid microenvironment that is vital for proper neuronal function. Altered endoneurial homeostasis as a secondary consequence of BNB dysregulation is considered an early pathological event in the course of a variety of traumatic, immune-mediated, or metabolically acquired peripheral neuropathies. In this review, emerging experimental advancements targeting the endoneurial microvasculature for the therapeutic management of immune-mediated inflammatory peripheral neuropathies, including the AIDP variant of Guillain-Barré syndrome, are discussed.

Nonlinear response to cancer nanotherapy due to macrophage interactions revealed by mathematical modeling and evaluated in a murine model via CRISPR-modulated macrophage polarization

Tumor-associated macrophages (TAMs) have been shown to both aid and hinder tumor growth, with patient outcomes potentially hinging on the proportion of M1, pro-inflammatory/growth-inhibiting, to M2, growth-supporting, phenotypes. Strategies to stimulate tumor regression by promoting polarization to M1 are a novel approach that harnesses the immune system to enhance therapeutic outcomes, including chemotherapy. We recently found that nanotherapy with mesoporous particles loaded with albumin-bound paclitaxel (MSV-nab-PTX) promotes macrophage polarization towards M1 in breast cancer liver metastases (BCLM). However, it remains unclear to what extent tumor regression can be maximized based on modulation of the macrophage phenotype, especially for poorly perfused tumors such as BCLM. Here, for the first time, a CRISPR system is employed to permanently modulate macrophage polarization in a controlled in vitro setting. This enables the design of 3D co-culture experiments mimicking the BCLM hypovascularized environment with various ratios of polarized macrophages. We implement a mathematical framework to evaluate nanoparticle-mediated chemotherapy in conjunction with TAM polarization. The response is predicted to be not linearly dependent on the M1:M2 ratio. To investigate this phenomenon, the response is simulated via the model for a variety of M1:M2 ratios. The modeling indicates that polarization to an all-M1 population may be less effective than a combination of both M1 and M2. Experimental results with the CRISPR system confirm this model-driven hypothesis. Altogether, this study indicates that response to nanoparticle-mediated chemotherapy targeting poorly perfused tumors may benefit from a fine-tuned M1:M2 ratio that maintains both phenotypes in the tumor microenvironment during treatment.

Applications and strategies in nanodiagnosis and nanotherapy in lung cancer

Lung cancer is the second most common cancer and the leading cause of death in both men and women in the world. Lung cancer is heterogeneous in nature and diagnosis is often at an advanced stage as it develops silently in the lung and is frequently associated with high mortality rates. Despite the advances made in understanding the biology of lung cancer, progress in early diagnosis, cancer therapy modalities and considering the mechanisms of drug resistance, the prognosis and outcome still remains low for many patients. Nanotechnology is one of the fastest growing areas of research that can solve many biological problems such as cancer. A growing number of therapies based on using nanoparticles (NPs) have successfully entered the clinic to treat pain, cancer, and infectious diseases. Recent progress in nanotechnology has been encouraging and directed to developing novel nanoparticles that can be one step ahead of the cancer reducing the possibility of multi-drug resistance. Nanomedicine using NPs is continuingly impacting cancer diagnosis and treatment. Chemotherapy is often associated with limited targeting to the tumor, side effects and low solubility that leads to insufficient drug reaching the tumor. Overcoming these drawbacks of chemotherapy by equipping NPs with theranostic capability which is leading to the development of novel strategies. This review provides a synopsis of current progress in theranostic applications for lung cancer diagnosis and therapy using NPs including liposome, polymeric NPs, quantum dots, gold NPs, dendrimers, carbon nanotubes and magnetic NPs.

Novel therapeutic strategies for Alzheimer's disease: Implications from cell-based therapy and nanotherapy

Alzheimer's disease (AD) is a multifactorial neurodegenerative disease which leads to progressive dysfunction of cognition, memory and learning in elderly people. Common therapeutic agents are not only inadequate to suppress the progression of AD pathogenesis but also produce deleterious side effects; hence, development of alternative therapies is required to specifically suppress complications of AD. The current review provides a commentary on conventional as well as novel therapeutic approaches with an emphasis on stem cell and nano-based therapies for improvement and management of AD pathogenesis. According to our overview of the current literature, AD is a multi-factorial disorder with various pathogenic trajectories; hence, a multifunctional strategy to create effective neuroprotective agents is required to treat this disorder.

Reactive oxygen species-responsive dexamethasone-loaded nanoparticles for targeted treatment of rheumatoid arthritis via suppressing the iRhom2/TNF-α/BAFF signaling pathway

Rheumatoid arthritis (RA) is an immune-mediated inflammatory disease that results in synovitis, cartilage destruction, and even loss of joint function. The frequent and long-term administration of anti-rheumatic drugs often leads to obvious adverse effects and patient non-compliance. Therefore, to specifically deliver dexamethasone (Dex) to inflamed joints and reduce the administration frequency of Dex, we developed Dex-loaded reactive oxygen species (ROS)-responsive nanoparticles (Dex/Oxi-αCD NPs) and folic acid (FA) modified Dex/Oxi-αCD NPs (Dex/FA-Oxi-αCD NPs) and validated their anti-inflammatory effect in vitro and in vivo. In vitro study demonstrated that these NPs can be effectively internalized by activated macrophages and the released Dex from NPs significantly downregulated the expression of iRhom2, TNF-α, and BAFF in activated Raw264.7. In vivo experiments revealed that Dex/Oxi-αCD NPs, especially Dex/FA-Oxi-αCD NPs significantly accumulated at inflamed joints in collagen-induced arthritis (CIA) mice and alleviated the joint swelling and cartilage destruction. Importantly, the expression of iRhom2, TNF-α, and BAFF in the joint was inhibited by intravenous injection of Dex/Oxi-αCD NPs and Dex/FA-Oxi-αCD NPs. Collectively, our data revealed that Dex-loaded ROS-responsive NPs can target inflamed joints and attenuate arthritis, and the 'iRhom2-TNF-α-BAFF' pathway plays an important role in the treatment of RA with the NPs, suggesting that this pathway may be a novel target for RA therapy.

Biodegraded magnetosomes with reduced size and heating power maintain a persistent activity against intracranial U87-Luc mouse GBM tumors

BACKGROUND

An important but rarely addressed question in nano-therapy is to know whether bio-degraded nanoparticles with reduced sizes and weakened heating power are able to maintain sufficient anti-tumor activity to fully eradicate a tumor, hence preventing tumor re-growth. To answer it, we studied magnetosomes, which are nanoparticles synthesized by magnetotactic bacteria with sufficiently large sizes (~ 30 nm on average) to enable a follow-up of nanoparticle sizes/heating power variations under two different altering conditions that do not prevent anti-tumor activity, i.e. in vitro cellular internalization and in vivo intra-tumor stay for more than 30 days.

RESULTS

When magnetosomes are internalized in U87-Luc cells by being incubated with these cells during 24 h in vitro, the dominant magnetosome sizes within the magnetosome size distribution (DMS) and specific absorption rate (SAR) strongly decrease from DMS ~ 40 nm and SAR ~ 1234 W/gFe before internalization to DMS ~ 11 nm and SAR ~ 57 W/gFe after internalization, a behavior that does not prevent internalized magnetosomes to efficiently destroy U87-Luc cell, i.e. the percentage of U87-Luc living cells incubated with magnetosomes decreases by 25% between before and after alternating magnetic field (AMF) application. When 2 µl of a suspension containing 40 µg of magnetosomes are administered to intracranial U87-Luc tumors of 2 mm3 and exposed (or not) to 15 magnetic sessions (MS), each one consisting in 30 min application of an AMF of 27 mT and 198 kHz, DMS and SAR decrease between before and after the 15 MS from ~ 40 nm and ~ 4 W/gFe down to ~ 29 nm and ~ 0 W/gFe. Although the magnetosome heating power is weakened in vivo, i.e. no measurable tumor temperature increase is observed after the sixth MS, anti-tumor activity remains persistent up to the 15th MS, resulting in full tumor disappearance among 50% of treated mice.

CONCLUSION

Here, we report sustained magnetosome anti-tumor activity under conditions of significant magnetosome size reduction and complete loss of magnetosome heating power.

Self-assembling poly(ethylene glycol)-block-polylactide-cabazitaxel conjugate nanoparticles for anticancer therapy with high efficacy and low in vivo toxicity

Traditional approaches used for transforming hydrophobic anticancer drugs into therapeutically available nanoparticles heavily rely on the noncovalent formulation of drugs within amphiphilic copolymers. However, these nanotherapies have not yet shown the expected favorable clinical outcomes in cancer patients, presumably due to their insufficient stability. To solve this dilemma, we conceive a new class of nanotherapies assembled with polymeric prodrugs that maintain pharmacological activity while substantially alleviate the drug toxicity in animals. By exploiting methoxypoly(ethylene glycol)-block-poly(D, L-lactic acid) (mPEG-PLA) as a promoiety, cabazitaxel is tethered to the terminus of the PLA fragment via a hydrolysable ester linkage. These conjugates recapitulate the self-assembly to produce colloidal stable nanotherapies. In a xenograft model of prostate cancer, this nanotherapy shows a durable inhibition of tumor progression upon the administration of a tolerable dose. Our results suggest that a hydrophobic and highly toxic drug can be rationally converted into a pharmacologically efficient and self-deliverable nanotherapy.

Role of Nanomedicine in Redox Mediated Healing at Molecular Level

Nanomedicine, the offspring born from the marriage of nanotechnology and medicine, has already brought momentous advances in the fight against a plethora of unmet diseases from cardiovascular and neurodegenerative to diabetes and cancer. Here, we review a conceptual framework that will provide a basic understanding about the molecular mechanism of action of a therapeutic nanomaterial inside biological milieu. In this review, we highlight how the catalytic nature of a transition metal oxide nanomaterial influences the cellular redox homeostasis, supports the cellular antioxidant defence system and reactivates the reactive oxygen species (ROS) mediated signalling to perform normal cell functions like cell cycle, differentiation, apoptosis, inflammation, toxicity, and protein interactions. With numerous examples, we describe the redox modulatory nature of d-block metal oxide nanomaterials and their biomimetic nanozyme activities to protect the mitochondria, the cellular redox mediator which prevents an organism from various diseases. This knowledge will be useful to design new nanomaterials capable of intracellular redox modulation, which in turn can be effective therapeutic agents for treatment of various unmet diseases that are beyond the ability of modern synthetic medicine.

Targeting integrins for cancer management using nanotherapeutic approaches: Recent advances and challenges

Integrins are the main cell surface receptors and execute multifaceted functions such as the bidirectional transmission of signals (i.e., inside-out and outside-in) and provide communication between cells and their microenvironments. Integrins are the key regulators of critical biological functions and contribute significantly to the promotion of cancer at almost every stage of disease progression from initial tumor formation to metastasis. Integrin expressions are frequently altered in different cancers, and consequently, several therapeutic strategies targeting integrins have been developed. Furthermore, nanotechnology-based approaches have been devised to overcome the intrinsic limitations of conventional therapies for cancer management, and have been shown to more precise, safer, and highly effective therapeutic tools. Although nanotechnology-based approaches have achieved substantial success for the management of cancer, certain obstacles remain such as inadequate knowledge of nano-bio interactions and the challenges associated with the three stages of clinical trials. This review highlights the different roles of integrins and of integrin-dependent signaling in various cancers and describes the applications of nanotherapeutics targeting integrins. In addition, we discuss RGD-based approaches and challenges posed to cancer management.

Mesenchymal stem cell-derived exosomes as a nanotherapeutic agent for amelioration of inflammation-induced astrocyte alterations in mice

Mesenchymal stem cell-derived exosomes (MSC-Exo) have robust anti-inflammatory effects in the treatment of neurological diseases such as epilepsy, stroke, or traumatic brain injury. While astrocytes are thought to be mediators of these effects, their precise role remains poorly understood. To address this issue, we investigated the putative therapeutic effects and mechanism of MSC-Exo on inflammation-induced alterations in astrocytes.

Methods: Lipopolysaccharide (LPS)-stimulated hippocampal astrocytes in primary culture were treated with MSC-Exo, which were also administered in pilocarpine-induced status epilepticus (SE) mice. Exosomal integration, reactive astrogliosis, inflammatory responses, calcium signaling, and mitochondrial membrane potentials (MMP) were monitored. To experimentally probe the molecular mechanism of MSC-Exo actions on the inflammation-induced astrocytic activation, we inhibited the nuclear factor erythroid-derived 2, like 2 (Nrf2, a key mediator in neuroinflammation and oxidative stress) by sgRNA (in vitro) or ML385 (Nrf2 inhibitor) in vivo.

Results: MSC-Exo were incorporated into hippocampal astrocytes as well as attenuated reactive astrogliosis and inflammatory responses in vitro and in vivo. Also, MSC-Exo ameliorated LPS-induced aberrant calcium signaling and mitochondrial dysfunction in culture, and SE-induced learning and memory impairments in mice. Furthermore, the putative therapeutic effects of MSC-Exo on inflammation-induced astrocytic activation (e.g., reduced reactive astrogliosis, NF-κB deactivation) were weakened by Nrf2 inhibition.

Conclusions: Our results show that MSC-Exo ameliorate inflammation-induced astrocyte alterations and that the Nrf2-NF-κB signaling pathway is involved in regulating astrocyte activation in mice. These data suggest the promising potential of MSC-Exo as a nanotherapeutic agent for the treatment of neurological diseases with hippocampal astrocyte alterations.

Efficient therapeutic effect of Nigella sativa aqueous extract and chitosan nanoparticles against experimentally induced Acanthamoeba keratitis

Acanthamoeba keratitis (AK) is a devastating, painful corneal infection, which may lead to loss of vision. The development of resistance and failure of the currently used drugs represent a therapeutic predicament. Thus, novel therapies with lethal effects on resistant Acanthamoeba are necessary to combat AK. In the present study, the curative effect of Nigella sativa aqueous extract (N. sativa) and chitosan nanoparticles (nCs) and both agents combined were assessed in experimentally induced AK. All inoculated corneas developed varying grades of AK. The study medications were applied on the 5th day postinoculation and were evaluated by clinical examination of the cornea and cultivation of corneal scraps. On the 10th day posttreatment, a 100% cure of AK was obtained with nCs (100 μg/ml) in grades 1 and 2 of corneal opacity as well as with N. sativa 60 mg/ml-nCs 100 μg/ml in grades 1, 2, and 3 of corneal opacity, highlighting a possible synergistic effect. On the 15th day posttreatment, a 100% cure was reached with N. sativa aqueous extract (60 mg/ml). Moreover, on the 20th day posttreatment, N. sativa (30 mg/ml) provided a cure rate of 87.5%, while nCs (50 μg/ml) as well as N. sativa 30 mg/ml-nCs 50 μg/ml yielded a cure rate of 75%; the lowest percentage of cure (25%) was obtained with chlorhexidine (0.02%), showing a non-significant difference compared to the parasite control. The clinical outcomes were in agreement with the results of corneal scrap cultivation. The results of the present study demonstrate the effectiveness of N. sativa aqueous extract and nCs (singly or combined) when used against AK, and these agents show potential for the development of new, effective, and safe therapeutic alternatives.

Modeling of nanoparticle transport through the female reproductive tract for the treatment of infectious diseases

The secreted mucus layer in the vaginal epithelium presents a formidable barrier to the transport of active agents for the prevention and treatment of female reproductive tract (FRT) infections. Nanoparticle-mediated drug delivery has been proposed to help facilitate the transport and release of active agents through the cervicovaginal mucus (CVM) and underlying mucosa. However, both nanoparticles (NPs) and free active agents face a variety of challenges, often requiring the administration of high localized doses to circumvent leakage and poor penetration to targeted intravaginal tissue compartments. To address these challenges, "stealth" NP modifications have been investigated, due to their favorable mucus-penetrating properties, resulting in improved intravaginal active agent retention and transport. A number of other NP characteristics including size, surface modification type, ligand density, and co-modification, as well as the complexity of the FRT tissue are involved in obtaining adequate tissue penetration and, if needed, cell internalization. Studies that systematically investigate variations of these characteristics have yet to be conducted, with the goal to obtain a better understanding of what properties most impact prophylactic and therapeutic benefit. To complement the progress made with experimental evaluation of active agent transport in in vitro and in vivo, mathematical modeling has recently been applied to analyze the transport performance of agents and delivery vehicles in the FRT. Here, we build upon this work to simulate NP transport through mucus gel, epithelial, and stromal compartments, with the goal to provide a platform that can systematically evaluate transport based on NP and tissue characteristics. Model parameters such as PEG density and NP release (decay) rate from mucus gel into the epithelium, are set from previous in vitro and in vivo experimental work that assessed the transport of poly(lactic-co-glycolic acid (PLGA) NPs. The modeling results show that while unmodified and 2% PEG-modified NPs were retained in mucus for ∼1-4 h, dependent upon decay constant values, and traverse to the epithelium, no NP penetration was observed in the stroma. In contrast, NPs modified with 3% PEG, exhibited prolonged retention in each compartment, remaining for ∼4-6 h. Moreover, a significant concentration of NPs is observed in the stroma, indicating a transition in transport behavior. For NPs modified with 5, 8, or 25% PEG, steady retention profiles were noted, which gradually decline over 24 h. To supplement this modeling study and to develop a more representative experimental system that may be useful in future work, we report on the feasibility of constructing single and multicellular layered (MCL) culture systems to represent the epithelial and stromal tissue of the FRT. We anticipate that a combined mathematical/experimental approach may longer term enable prediction and customization of patient tissue-specific approaches to attain effective NP-mediated drug delivery and release for the treatment of infectious disease.

Use of nano engineered approaches to overcome the stromal barrier in pancreatic cancer

While chemotherapy is the only approved non-surgical option for the majority of pancreatic cancer patients, it rarely results in a cure. The failure to respond to chemotherapy is due to the presence of an abundant dysplastic stroma that interferes in drug delivery and as a result of drug resistance. It is appropriate, therefore, to consider the stromal contribution to the resistance to chemotherapy and sidestepping this barrier with nanocarriers that improve survival outcome. In this paper, we provide a short overview of the role of the stroma in chemotherapy resistance, including the use of nanocarriers to negate this barrier. We provide a perspective and guidance towards the implementation of nanotherapeutic approaches to improve therapeutic delivery and efficacy of PDAC management.

Combinatorial drug delivery strategy employing nano-curcumin and nano-MiADMSA for the treatment of arsenic intoxication in mouse

Chelation therapy is the mainstream treatment for heavy metal poisoning. Apart from this, therapy using antioxidant/herbal extracts are the other strategies now commonly being tried for the treatment. We have previously reported individual beneficial efficacy of nanoparticle mediated administration of an antioxidant like 'curcumin' and an arsenic chelator 'monoisoamyl 2,3-dimercaptosuccinic acid (MiADMSA)' for the treatment of arsenic toxicity compared to bulk drugs. The present paper investigates our hypothesis that a combination drug delivery therapy employing two nanosystems, a chelator and a strong antioxidant, may produce more pronounced therapeutic effects compared to individual effects in the treatment of arsenic toxicity. An in-vivo study was conducted wherein arsenic as sodium arsenite (100 ppm) was administered in drinking water for 5 months to Swiss albino mice. This was followed by a treatment protocol comprising of curcumin encapsulated chitosan nanoparticles (nano-curcumin, 15 mg/kg, orally for 1 month) either alone or in combination with MiADMSA encapsulated polymeric nanoparticles (nano-MiADMSA, 50 mg/kg for last 5 days) to evaluate the therapeutic potential of the combination treatment. Our results demonstrated that co-treatment with nano-curcumin and nano-MiADMSA provided beneficial effects in a synergistic way on the adverse changes in oxidative stress parameters and metal status induced by arsenic.

Enhancement of the Immune Function by Titanium Dioxide Nanorods and Their Application in Cancer Immunotherapy

With the rapid development of nanotherapy, concerns surrounding the possible use of nanomaterials-mediated immunomodulation are growing. Thus, evaluating the effects of novel materials for potential application in nanotherapy is essential. Herein, we studied the effects of TiO2-nanorods (NRs) on the immune function and their potential application in immunotherapy. TiO2-NRs exerted specific immunomodulatory effects on the main immune cells. Cytokines TNF-α and IL-2, which play a key role in antitumor processes, were upregulated more significantly than other cytokines (IL-4, IL-5, IFN-γ) in the main immune cells. The cells group treated with a high dose of TiO2-NRs (50 mg/L) for 12 h produced a higher TNF-α content of 530.4 pg/mL relative to that (238.2 pg/mL) treated with saline solution only. The TNF-α content increased to 2.2- and 4.9-fold for macrophages and lymphocytes, respectively. Also, we conclude that TiO2-NRs exposure may trigger T cell proliferation and bias toward Th1 immune response and cause a long-lasting activation of lymphocytes involved in adaptive immunity rather than an innate immunity in BALB/c mice. Furthermore, we explored the potential application of TiO2-NRs in immunotherapy. At a given dose of 1 mg/kg, the inhibition rate by TiO2-NRs (26.7%) was much higher than that by DOX (13.3%).

Pro-inflammatory chitosan/poly(γ-glutamic acid) nanoparticles modulate human antigen-presenting cells phenotype and revert their pro-invasive capacity

Anticancer immune responses depend on efficient presentation of tumor antigens and co-stimulatory signals provided by antigen-presenting cells (APCs). However, it is described that immature dendritic cells (DCs) and macrophages at the tumor site may have an immunosuppressive profile, which limits the activity of effector T cells and supports tumor progression. Therapeutic targeting of these innate immune cells, either aiming at their elimination or re-polarization towards an immunostimulatory profile, has been pointed as an attractive approach to control tumor progression. In the present work, we assessed the potential of Chitosan (Ch)/Poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) to modulate macrophages and DCs inflammatory profile and to impair their ability to promote cancer cell invasion. Interestingly, Ch/γ-PGA NPs, prepared by co-acervation method, induced an immunostimulatory DCs phenotype, enhancing the expression of the co-stimulatory molecules CD86, CD40 and HLA-DR, and the secretion of the pro-inflammatory cytokines TNF-α, IL-12p40 and IL-6. Furthermore, Ch/γ-PGA NPs re-educated IL-10-stimulated macrophages towards a pro-inflammatory profile, decreasing the expression of CD163 and promoting the secretion of IL-12p40 and TNF-α. These alterations in the immune cells phenotype promoted CD4⁺ and CD8⁺ T cell activation/proliferation and partially inhibited APCs' ability to induce colorectal cancer cell invasion. Overall, our findings open new perspectives on the use of Ch/γ-PGA NPs as an immunomodulatory therapy for antigen-presenting cells reprogramming, providing a new tool for anticancer therapies.

STATEMENT OF SIGNIFICANCE

The immune system is responsible to detect and destroy abnormal cells preventing the development of cancer. However, the immunosuppressive tumor microenvironment can compromise the immune response favoring tumor progression. Thus, immune system modulation towards an immunostimulatory profile can improve anticancer therapies. This research focus on the development of chitosan/poly(γ-glutamic acid) nanoparticles (NPs) to modulate human antigen-presenting cells (APCs) phenotype and to counteract their pro-invasive capacity. Interestingly, Ch/γ-PGA NPs had a prominent effect in inducing macrophages and dendritic cells immunostimulatory phenotype, thus favoring T cell proliferation and inhibiting colorectal cancer cell invasion. We propose that their combination with other immunomodulatory drugs or conventional anticancer therapies can improve patients' outcome.

Exploiting Enzyme Alterations in Cancer for Drug Activation, Drug Delivery, and Nanotherapy

Alterations of enzyme activity or enzyme levels in cancer tissue have been documented over the years. Taking advantage of these observations, various strategies for drug activation and drug delivery have been developed. One example is a mechanism called "prodrugs" that generates active drugs by enzyme cleavage. Another example is enzyme-induced anticancer drug release mechanisms. This system is constructed by incorporating enzyme-sensitive linkages to materials such as hydrogels and nanodelivery vehicles, including liposomes, polymer micelles, and mesoporous silica nanoparticles. Various release mechanisms for anticancer drugs and siRNA have been developed. In addition, enzyme cleavage is utilized in nanodelivery vehicles that contain nanomachines. One example is nanovalve that can be opened by enzyme cleavage. Another example is enzyme-induced release of nanoparticles from multistage vehicles. Finally, colon-specific drug delivery by azoreductase cleavable mechanism is discussed.

New perspectives in nanotherapeutics for chronic respiratory diseases

According to the World Health Organization (WHO), hundreds of millions of people of all ages and in all countries suffer from chronic respiratory diseases, with particular negative consequences such as poor health-related quality of life, impaired work productivity, and limitations in the activities of daily living. Chronic obstructive pulmonary disease, asthma, occupational lung diseases (such as silicosis), cystic fibrosis, and pulmonary arterial hypertension are the most common of these diseases, and none of them are curable with current therapies. The advent of nanotechnology holds great therapeutic promise for respiratory conditions, because non-viral vectors are able to overcome the mucus and lung remodeling barriers, increasing pharmacologic and therapeutic potency. It has been demonstrated that the extent of pulmonary nanoparticle uptake depends not only on the physical and chemical features of nanoparticles themselves, but also on the health status of the organism; thus, the huge diversity in nanotechnology could revolutionize medicine, but safety assessment is a challenging task. Within this context, the present review discusses some of the major new perspectives in nanotherapeutics for lung disease and highlights some of the most recent studies in the field.

Graphene-VP40 interactions and potential disruption of the Ebola virus matrix filaments

Ebola virus infections cause hemorrhagic fever that often results in very high fatality rates. In addition to exploring vaccines, development of drugs is also essential for treating the disease and preventing the spread of the infection. The Ebola virus matrix protein VP40 exists in various conformational and oligomeric forms and is a potential pharmacological target for disrupting the virus life-cycle. Here we explored graphene-VP40 interactions using molecular dynamics simulations and graphene pelleting assays. We found that graphene sheets associate strongly with VP40 at various interfaces. We also found that the graphene is able to disrupt the C-terminal domain (CTD-CTD) interface of VP40 hexamers. This VP40 hexamer-hexamer interface is crucial in forming the Ebola viral matrix and disruption of this interface may provide a method to use graphene or similar nanoparticle based solutions as a disinfectant that can significantly reduce the spread of the disease and prevent an Ebola epidemic.

TCTP Has a Crucial Role in the Different Stages of Prostate Cancer Malignant Progression

Prostate cancer (PC) is the second most common cause of cancer-related mortality in men in the western world after lung cancer. Many patients are not candidates for resection given the advanced stage of their cancer. The primary treatment for advanced PC is the castration therapy which supresses the production of androgens, hormone that promotes PC growth. Despite the efficiency of the castration therapy, most patients develop castration resistant disease which remains uncurable. Clearly, novel approaches are required to effectively treat castration resistant PC (CRPC). New strategies that identify the molecular mechanisms by which PC becomes resistant to conventional therapies may enable the identification of novel therapeutic targets that could improve clinical outcome. Recent studies have demonstrated the implication of TCTP's over-expression in PC and CRPC, and its role in resistance to treatment. TCTP's interaction with p53 and their negative feedback loop regulation have also been described to be causal for PC progression and invasion. A novel nanotherapy that inhibits TCTP has been developed as a new therapeutical strategy in CRPC. This chapter will highlight the role of TCTP as new therapeutic target in PC, in particular, therapy-resistant advanced PC and report the development of novel nanotherapy against TCTP that restore treatment-sensitivity in CRPC that deserve to be tested in clinical trial.

The Tumor Microenvironment as a Barrier to Cancer Nanotherapy

Although extensive research effort and resources have been dedicated to the development of nanotherapeutics to treat cancer, few formulations have reached clinical application. A major reason is that the large number of parameters available to tune nanotherapy characteristics coupled with the variability in tumor tissue precludes evaluation of complex interactions through experimentation alone. In order to optimize the nanotechnology design and gain further insight into these phenomena, mathematical modeling and computational simulation have been applied to complement empirical work. In this chapter, we discuss modeling work related to nanotherapy and the tumor microenvironment. We first summarize the biology underlying the dysregulated tumor microenvironment, followed by a description of major nano-scale parameters. We then present an overview of the mathematical modeling of cancer nanotherapy, including evaluation of nanotherapy in multi-dimensional tumor tissue, coupling of nanotherapy with vascular flow, modeling of nanotherapy in combination with in vivo imaging, modeling of nanoparticle transport based on in vitro data, modeling of vasculature-bound nanoparticles, evaluation of nanotherapy using pharmacokinetic modeling, and modeling of nano-based hyperthermia. We conclude that an even tighter interdisciplinary effort between biological, material, and physical scientists is needed in order to eventually overcome the tumor microenvironment barrier to successful nanotherapy.

Myelin repair in vivo is increased by targeting oligodendrocyte precursor cells with nanoparticles encapsulating leukaemia inhibitory factor (LIF)

Multiple sclerosis (MS) is a progressive demyelinating disease of the central nervous system (CNS). Many nerve axons are insulated by a myelin sheath and their demyelination not only prevents saltatory electrical signal conduction along the axons but also removes their metabolic support leading to irreversible neurodegeneration, which currently is untreatable. There is much interest in potential therapeutics that promote remyelination and here we explore use of leukaemia inhibitory factor (LIF), a cytokine known to play a key regulatory role in self-tolerant immunity and recently identified as a pro-myelination factor. In this study, we tested a nanoparticle-based strategy for targeted delivery of LIF to oligodendrocyte precursor cells (OPC) to promote their differentiation into mature oligodendrocytes able to repair myelin. Poly(lactic-co-glycolic acid)-based nanoparticles of ∼120 nm diameter were constructed with LIF as cargo (LIF-NP) with surface antibodies against NG-2 chondroitin sulfate proteoglycan, expressed on OPC. In vitro, NG2-targeted LIF-NP bound to OPCs, activated pSTAT-3 signalling and induced OPC differentiation into mature oligodendrocytes. In vivo, using a model of focal CNS demyelination, we show that NG2-targeted LIF-NP increased myelin repair, both at the level of increased number of myelinated axons, and increased thickness of myelin per axon. Potency was high: a single NP dose delivering picomolar quantities of LIF is sufficient to increase remyelination. Impact statement Nanotherapy-based delivery of leukaemia inhibitory factor (LIF) directly to OPCs proved to be highly potent in promoting myelin repair in vivo: this delivery strategy introduces a novel approach to delivering drugs or biologics targeted to myelin repair in diseases such as MS.

Release kinetics of paclitaxel and cisplatin from two and three layered gold nanoparticles

Gold nanoparticles functionalized with biologically compatible layers may achieve stable drug release while avoiding adverse effects in cancer treatment. We study cisplatin and paclitaxel release from gold cores functionalized with hexadecanethiol (TL) and phosphatidylcholine (PC) to form two-layer nanoparticles, or TL, PC, and high density lipoprotein (HDL) to form three-layer nanoparticles. Drug release was monitored for 14 days to assess long term effects of the core surface modifications on release kinetics. Release profiles were fitted to previously developed kinetic models to differentiate possible release mechanisms. The hydrophilic drug (cisplatin) showed an initial (5-h) burst, followed by a steady release over 14 days. The hydrophobic drug (paclitaxel) showed a steady release over the same time period. Two layer nanoparticles released 64.0±2.5% of cisplatin and 22.3±1.5% of paclitaxel, while three layer nanoparticles released the entire encapsulated drug. The Korsmeyer-Peppas model best described each release scenario, while the simplified Higuchi model also adequately described paclitaxel release from the two layer formulation. We conclude that functionalization of gold nanoparticles with a combination of TL and PC may help to modulate both hydrophilic and hydrophobic drug release kinetics, while the addition of HDL may enhance long term release of hydrophobic drug.

Modelling of a targeted nanotherapeutic 'stroma' to deliver the cytokine LIF, or XAV939, a potent inhibitor of Wnt-β-catenin signalling, for use in human fetal dopaminergic grafts in Parkinson's disease

The endogenous reparative capacity of the adult human brain is low, and chronic neurodegenerative disorders of the central nervous system represent one of the greatest areas of unmet clinical need in the developing world. Novel therapeutic strategies to treat them include: (i) growth factor delivery to boost endogenous repair and (ii) replacement cell therapy, including replacing dopaminergic neurons to treat Parkinson’s disease (PD). However, these approaches are restricted not only by rapid degradation of growth factors, but also by the limited availability of cells for transplant and the poor survival of implanted cells that lack the necessary stromal support. We therefore hypothesised that provision of a transient artificial stroma for paracrine delivery of pro-survival factors could overcome both of these issues. Using leukaemia inhibitory factor (LIF) – a proneural, reparative cytokine – formulated as target-specific poly(lactic-co-glycolic acid) (PLGA) nano-particles (LIF-nano-stroma), we discovered that attachment of LIF-nano-stroma to freshly isolated fetal dopaminergic cells improved their survival fourfold: furthermore, in vivo, the number of surviving human fetal dopaminergic cells tended to be higher at 3 months after grafting into the striatum of nude rats, compared with controls treated with empty nanoparticles. In addition, we also analysed the effect of a novel nano-stroma incorporating XAV939 (XAV), a potent inhibitor of the developmentally important Wnt–β-catenin signalling pathway, to investigate whether it could also promote the survival and differentiation of human fetal dopaminergic precursors; we found that the numbers of both tyrosine-hydroxylase-positive neurons (a marker of dopaminergic neurons) and total neurons were increased. This is the first demonstration that LIF-nano-stroma and XAV-nano-stroma each have pro-survival effects on human dopaminergic neurons, with potential value for target-specific modulation of neurogenic fate in cell-based therapies for PD.