Transport of drugs across the blood-brain barrier by nanoparticles

Quercetin-biapigenin nanoparticles are effective to penetrate the blood-brain barrier

Search for efficient therapeutic agents for central nervous system (CNS) disorders has been extensive. Nevertheless, blood-brain barrier (BBB) is an obstacle that prevents the majority of compounds to act in these diseases. It is, thus, of extreme relevance the BBB overcome, in order to deliver a drugs therapeutically active concentration to the action site, with the least losses and interaction with other organs, tissues, or cells. The present study aimed to investigate the potential protective effect of quercetin-biapigenin encapsulated into poly(Ɛ-polycaprolactone) (PCL) nanoparticles against t-BOOH-induced oxidative stress in several brain cell lines, as well as evaluate the permeability of those active molecules through an in vitro BBB model. The three cell lines under study (BV-2, hcmec/D3, and U87) presented different reactions to t-BOOH. In general, quercetin-biapigenin PCL-loaded nanoparticles were able to minimize compound toxicity they convey, regardless the cell line. Quercetin-biapigenin PCL-loaded nanoparticles (Papp of approximately 80 × 10-6 cm/s) revealed to be more permeable than free compounds (Papp of approximately 50 × 10-6 cm/s). As of our knowledge, this is the first report of quercetin-biapigenin PCL-loaded nanoparticle activity in brain cells. It is also the first determining its permeability through BBB, as an effective nanocarrier for brain delivery.

Nanocarriers Call the Last Shot in the Treatment of Brain Cancers

Our brain is protected by physio-biological barriers. The blood–brain barrier (BBB) main mechanism of protection relates to the abundance of tight junctions (TJs) and efflux pumps. Although BBB is crucial for healthy brain protection against toxins, it also leads to failure in a devastating disease like brain cancer. Recently, nanocarriers have been shown to pass through the BBB and improve patients’ survival rates, thus becoming promising treatment strategies. Among nanocarriers, inorganic nanocarriers, solid lipid nanoparticles, liposomes, polymers, micelles, and dendrimers have reached clinical trials after delivering promising results in preclinical investigations. The size of these nanocarriers is between 10 and 1000 nm and is modified by surface attachment of proteins, peptides, antibodies, or surfactants. Multiple research groups have reported transcellular entrance as the main mechanism allowing for these nanocarriers to cross BBB. Transport proteins and transcellular lipophilic pathways exist in BBB for small and lipophilic molecules. Nanocarriers cannot enter via the paracellular route, which is limited to water-soluble agents due to the TJs and their small pore size. There are currently several nanocarriers in clinical trials for the treatment of brain cancer. This article reviews challenges as well as fitting attributes of nanocarriers for brain tumor treatment in preclinical and clinical studies.

Collagen Nanoparticles in Drug Delivery Systems and Tissue Engineering

The versatile natural polymer, collagen, has gained vast attention in biomedicine. Due to its biocompatibility, biodegradability, weak antigenicity, biomimetics and well-known safety profile, it is widely used as a drug, protein and gene carrier, and as a scaffold matrix in tissue engineering. Nanoparticles develop favorable chemical and physical properties such as increased drug half-life, improved hydrophobic drug solubility and controlled and targeted drug release. Their reduced toxicity, controllable characteristics of scaffolds and stimuli-responsive behavior make them suitable in regenerative medicine and tissue engineering. Collagen associates and absorbs nanoparticles leading to significant impacts on their biological functioning in any biofluid. This review will discuss collagen nanoparticle preparation methods and their applications and developments in drug delivery systems and tissue engineering.

Simulation of magnetic nanoparticles crossing through a simplified blood-brain barrier model for Glioblastoma multiforme treatment

BACKGROUND AND OBJECTIVES

Glioblastoma multiforme is considered as one of the most aggressive types of cancer, while various treatment techniques have been proposed. Magnetic nanoparticles (MNPs) loaded with drug and magnetically controlled and targeted to tissues affected by disease, is considered as a possible treatment. However, MNPs are difficult to penetrate the central nervous system and approach the unhealthy tissue, because of the blood-brain barrier (BBB). This study investigates numerically the delivery of magnetic nanoparticles through the barrier driven by normal pressure drop and external gradient magnetic fields, employing a simplified geometrical model, computational fluid dynamics and discrete element method. The goal of the study is to provide information regarding the permeability of the BBB under various conditions like the imposed forces and the shape of the domain, as a preliminary predictive tool.

METHODS

To achieve that, the three-dimensional Navier-Stokes equations are solved in the margin of a blood vessel along with a discrete model for the MNPs with various acting forces. The numerical results are compared with experimental measurements showing that the model can predict acceptably the flow behavior.

RESULTS

The effect of nanoparticles' size, external magnetic field and blood flow in the vessel, on the brain-barrier's permeability are investigated. Three different cases of available area among the endothelial cells per the MNPs' size ratio are also examined, showing that the MNPs' size and available area is not the dominant parameter affecting the permeability of the BBB. The results indicate that the applied magnetic field enhances the drug delivery into the central nervous system (CNS). When larger MNPs (∼100 nm) are exposed to an external magnetic field, the permeability can be improved up to 30%, while it is shown that smaller MNPs (∼10 nm) cannot be driven by the applied magnetic field and in this case the permeability remains relatively unchanged. Finally, the blood flow increase leads to a permeability improvement up to 15%.

CONCLUSIONS

The applied magnetic field improves up to 45% the permeability of the BBB for MNPs of 100 nm. The geometric characteristics of the endothelial cells, the nanoparticles' size and the blood flow are not so decisive parameters for the drug delivery into the CNS, compared to the external magnetic force.

Nanoparticles for Targeted Brain Drug Delivery: What Do We Know?

The blood-brain barrier (BBB) is a barrier that separates the blood from the brain tissue and possesses unique characteristics that make the delivery of drugs to the brain a great challenge. To achieve this purpose, it is necessary to design strategies to allow BBB passage, in order to reach the brain and target the desired anatomic region. The use of nanomedicine has great potential to overcome this problem, since one can modify nanoparticles with strategic molecules that can interact with the BBB and induce uptake through the brain endothelial cells and consequently reach the brain tissue. This review addresses the potential of nanomedicines to treat neurological diseases by using nanoparticles specially developed to cross the BBB.

Optimizing the Design of Blood-Brain Barrier-Penetrating Polymer-Lipid-Hybrid Nanoparticles for Delivering Anticancer Drugs to Glioblastoma

PURPOSE

Chemotherapy for glioblastoma multiforme (GBM) remains ineffective due to insufficient penetration of therapeutic agents across the blood-brain barrier (BBB) and into the GBM tumor. Herein, is described, the optimization of the lipid composition and fabrication conditions for a BBB- and tumor penetrating terpolymer-lipid-hybrid nanoparticle (TPLN) for delivering doxorubicin (DOX) to GBM.

METHODS

The composition of TPLNs was first screened using different lipids based on nanoparticle properties and in vitro cytotoxicity by using 2³ full factorial experimental design. The leading DOX loaded TPLNs (DOX-TPLN) were prepared by further optimization of conditions and used to study cellular uptake mechanisms, in vitro cytotoxicity, three-dimensional (3D) glioma spheroid penetration, and in vivo biodistribution in a murine orthotopic GBM model.

RESULTS

Among various lipids studied, ethyl arachidate (EA) was found to provide excellent nanoparticle properties e.g., size, polydispersity index (PDI), zeta potential, encapsulation efficiency, drug loading, and colloidal stability, and highest anticancer efficacy for DOX-TPLN. Further optimized EA-based TPLNs were prepared with an optimal particle size (103.8 ± 33.4 nm) and PDI (0.208 ± 0.02). The resultant DOX-TPLNs showed ~ sevenfold higher efficacy than free DOX against human GBM U87-MG-RED-FLuc cells in vitro. The interaction between the TPLNs and the low-density lipoprotein receptors also facilitated cellular uptake, deep penetration into 3D glioma spheroids, and accumulation into the in vivo brain tumor regions of DOX-TPLNs.

CONCLUSION

This work demonstrated that the TPLN system can be optimized by rational selection of lipid type, lipid content, and preparation conditions to obtain DOX-TPLN with enhanced anticancer efficacy and GBM penetration and accumulation.

Design and Development of Nanomaterial-Based Drug Carriers to Overcome the Blood-Brain Barrier by Using Different Transport Mechanisms

Central nervous system (CNS) diseases are the leading causes of death and disabilities in the world. It is quite challenging to treat CNS diseases efficiently because of the blood-brain barrier (BBB). It is a physical barrier with tight junction proteins and high selectivity to limit the substance transportation between the blood and neural tissues. Thus, it is important to understand BBB transport mechanisms for developing novel drug carriers to overcome the BBB. This paper introduces the structure of the BBB and its physiological transport mechanisms. Meanwhile, different strategies for crossing the BBB by using nanomaterial-based drug carriers are reviewed, including carrier-mediated, adsorptive-mediated, and receptor-mediated transcytosis. Since the viral-induced CNS diseases are associated with BBB breakdown, various neurotropic viruses and their mechanisms on BBB disruption are reviewed and discussed, which are considered as an alternative solution to overcome the BBB. Therefore, most recent studies on virus-mimicking nanocarriers for drug delivery to cross the BBB are also reviewed and discussed. On the other hand, the routes of administration of drug-loaded nanocarriers to the CNS have been reviewed. In sum, this paper reviews and discusses various strategies and routes of nano-formulated drug delivery systems across the BBB to the brain, which will contribute to the advanced diagnosis and treatment of CNS diseases.

Lipid nanostructures for targeting brain cancer

Advancements in both material science and bionanotechnology are transforming the health care sector. To this end, nanoparticles are increasingly used to improve diagnosis, monitoring, and therapy. Huge research is being carried out to improve the design, efficiency, and performance of these nanoparticles. Nanoparticles are also considered as a major area of research and development to meet the essential requirements for use in nanomedicine where safety, compatibility, biodegradability, biodistribution, stability, and effectiveness are requirements towards the desired application. In this regard, lipids have been used in pharmaceuticals and medical formulations for a long time. The present work focuses on the use of lipid nanostructures to combat brain tumors. In addition, this review summarizes the literature pertaining to solid lipid nanoparticles (SLN) and nanostructured lipid carriers (LNC), methods of preparation and characterization, developments achieved to overcome blood brain barrier (BBB), and modifications used to increase their effectiveness.

Alkoxy cyanoacrylate-based nanoparticles with stealth and brain-targeting properties

Nanoparticles (NPs) with 'stealth' properties have been designed to decrease the phagocytosis of such particles by mononuclear phagocytes and to protect them from enzymatic degradation, thus improving circulation time and bioavailability after intravenous administration. Brain-targeting modifications endow NPs with the capacity to cross the blood-brain barrier, facilitating chemotherapy for brain diseases such as glioma. In this study, newly designed alkoxy cyanoacrylate (CA)-based NPs with stealth and brain-targeting properties were synthesised and evaluated. The monomers for NP core polymerisation were chemically modified to hydrophilic short alkoxy structure for stealth purposes and coated with polysorbate-80 for brain targeting. Two monomers (2-methoxyethyl CA and 2-(2-methoxyethyl)ethyl CA) were used to create NP₂ and NP₃, respectively. Both NPs were successfully loaded with anti-sense oligonucleotide (ASON) of transforming growth factor beta 2. Compared to traditional n-butyl CA-based ASON-NP₁, ASON-NP₃ was found to decrease phagocytosis by mononuclear macrophages (RAW264.7) and to increase cellular uptake by cancer cells. ASON-NP₃ showed definite brain targeting and anti-cancer effects. This work provides a potential new strategy for preparing stealth NPs core, providing a new NP vehicle for clinical drug delivery that may be targeted to the brain and circulates in the blood for an extended period of time.

Dopamine-loaded nanoparticle systems circumvent the blood-brain barrier restoring motor function in mouse model for Parkinson's Disease

Parkinson's disease (PD) is a progressive and chronic neurodegenerative disease of the central nervous system. Early treatment for PD is efficient; however, long-term systemic medication commonly leads to deleterious side-effects. Strategies that enable more selective drug delivery to the brain using smaller dosages, while crossing the complex brain-blood barrier (BBB), are highly desirable to ensure treatment efficacy and decrease/avoid unwanted outcomes. Our goal was to design and test the neurotherapeutic potential of a forefront nanoparticle-based technology composed of albumin/PLGA nanosystems loaded with dopamine (ALNP-DA) in 6-OHDA PD mice model. ALNP-DA effectively crossed the BBB, replenishing dopamine at the nigrostriatal pathway, resulting in significant motor symptom improvement when compared to Lesioned and L-DOPA groups. Notably, ALNP-DA (20 mg/animal dose) additionally up-regulated and restored motor coordination, balance, and sensorimotor performance to non-lesioned (Sham) animal level. Overall, ALNPs represent an innovative, non-invasive nano-therapeutical strategy for PD, considering its efficacy to circumvent the BBB and ultimately deliver the drug of interest to the brain.

Carbon Dots: A Future Blood-Brain Barrier Penetrating Nanomedicine and Drug Nanocarrier

Drug delivery across the blood-brain barrier (BBB) is one of the biggest challenges in modern medicine due to the BBB's highly semipermeable property that limits most therapeutic agents of brain diseases to enter the central nervous system (CNS). In recent years, nanoparticles, especially carbon dots (CDs), exhibit many unprecedented applications for drug delivery. Several types of CDs and CD-ligand conjugates have been reported successfully penetrating the BBB, which shows a promising progress in the application of CD-based drug delivery system (DDS) for the treatment of CNS diseases. In this review, our discussion of CDs includes their classification, preparations, structures, properties, and applications for the treatment of neurodegenerative diseases, especially Alzheimer's disease (AD) and brain tumor. Moreover, abundant functional groups on the surface, especially amine and carboxyl groups, allow CDs to conjugate with diverse drugs as versatile drug nanocarriers. In addition, structure of the BBB is briefly described, and mechanisms for transporting various molecules across the BBB and other biological barriers are elucidated. Most importantly, recent developments in drug delivery with CDs as BBB-penetrating nanodrugs and drug nanocarriers to target CNS diseases especially Alzheimer's disease and brain tumor are summarized. Eventually, future prospects of the CD-based DDS are discussed in combination with the development of artificial intelligence and nanorobots.

Comparison of cubosomes and hexosomes for the delivery of phenytoin to the brain

The ability to formulate cubosomes and hexosomes with a single lipid by changing only the colloidal stabiliser presents a unique opportunity to directly compare the biological performance of these uniquely structured nanoparticles. This was explored here via the encapsulation and brain delivery of a model anti-seizure drug, phenytoin, in selachyl alcohol cubosomes and hexosomes. Nanoparticles were prepared with Pluronic® F127 or Tween 80® as the stabiliser and characterised. The internal nanostructure of nanoparticles shifted from hexosomes when using Pluronic® F127 as the stabiliser to cubosomes when using Tween 80® and was conserved following loading of phenytoin, with high encapsulation efficiencies (>97%) in both particle type. Cytotoxicity towards brain endothelial cells using the hCMEC/D3 line was comparable regardless of stabiliser type. Finally, in vivo brain delivery of phenytoin encapsulated in cubosomes and hexosomes after intravenous administration to rats was studied over a period of 60 min, showing cubosomes to be superior to hexosomes, both in terms of brain concentrations and brain to plasma ratio. While the role of stabiliser and/or internal nanostructure remains to be conclusively determined, this study is the first in vivo comparison of cubosomes and hexosomes for the delivery of a therapeutic drug molecule across the BBB and into the brain.

Citrate-Coated Magnetic Polyethyleneimine Composites for Plasmid DNA Delivery into Glioblastoma

Several ternary composites that are based on branched polyethyleneimine (bPEI 25 kDa, polydispersity 2.5, 0.1 or 0.2 ng), citrate-coated ultrasmall superparamagnetic iron oxide nanoparticles (citrate-NPs, 8-10 nm, 0.1, 1.0, or 2.5 µg), and reporter circular plasmid DNA pEGFP-C1 or pRL-CMV (pDNA 0.5 µg) were studied for optimization of the best composite for transfection into glioblastoma U87MG or U138MG cells. The efficiency in terms of citrate-NP and plasmid DNA gene delivery with the ternary composites could be altered by tuning the bPEI/citrate-NP ratios in the polymer composites, which were characterized by Prussian blue staining, in vitro magnetic resonance imaging as well as green fluorescence protein and luciferase expression. Among the composites prepared, 0.2 ng bPEI/0.5 μg pDNA/1.0 µg citrate-NP ternary composite possessed the best cellular uptake efficiency. Composite comprising 0.1 ng bPEI/0.5 μg pDNA/0.1 μg citrate-NP gave the optimal efficiency for the cellular uptake of the two plasmid DNAs to the nucleus. The best working bPEI concentration range should not exceed 0.2 ng/well to achieve a relatively low cytotoxicity.

The Emerging Role of Topical Ocular Drugs to Target the Posterior Eye

The prevalence of chronic fundus diseases is increasing with the aging of the general population. The treatment of these intraocular diseases relies on invasive drug delivery because of the globular structure and multiple barriers of the eye. Frequent intraocular injections bring heavy burdens to the medical care system and patients. The use of topical drugs to treat retinal diseases has always been an attractive solution. The fast development of new materials and technologies brings the possibility to develop innovative topical formulations. This article reviews anatomical and physiological barriers of the eye which affect the bioavailability of topical drugs. In addition, we summarize innovative topical formulations which enhance the permeability of drugs through the ocular surface and/or extend the drug retention time in the eye. This article also reviews the differences of eyes between different laboratory animals to address the translational challenges of preclinical models. The fast development of in vitro eye models may provide more tools to increase the clinical translationality of topical formulations for intraocular diseases. Clinical successes of topical formulations rely on continuous and collaborative efforts between different disciplines.

Neurotrophic Factors in Parkinson's Disease: Clinical Trials, Open Challenges and Nanoparticle-Mediated Delivery to the Brain

Neurotrophic factors (NTFs) are small secreted proteins that support the development, maturation and survival of neurons. NTFs injected into the brain rescue and regenerate certain neuronal populations lost in neurodegenerative diseases, demonstrating the potential of NTFs to cure the diseases rather than simply alleviating the symptoms. NTFs (as the vast majority of molecules) do not pass through the blood-brain barrier (BBB) and therefore, are delivered directly into the brain of patients using costly and risky intracranial surgery. The delivery efficacy and poor diffusion of some NTFs inside the brain are considered the major problems behind their modest effects in clinical trials. Thus, there is a great need for NTFs to be delivered systemically thereby avoiding intracranial surgery. Nanoparticles (NPs), particles with the size dimensions of 1-100 nm, can be used to stabilize NTFs and facilitate their transport through the BBB. Several studies have shown that NTFs can be loaded into or attached onto NPs, administered systemically and transported to the brain. To improve the NP-mediated NTF delivery through the BBB, the surface of NPs can be functionalized with specific ligands such as transferrin, insulin, lactoferrin, apolipoproteins, antibodies or short peptides that will be recognized and internalized by the respective receptors on brain endothelial cells. In this review, we elaborate on the most suitable NTF delivery methods and envision "ideal" NTF for Parkinson's disease (PD) and clinical trial thereof. We shortly summarize clinical trials of four NTFs, glial cell line-derived neurotrophic factor (GDNF), neurturin (NRTN), platelet-derived growth factor (PDGF-BB), and cerebral dopamine neurotrophic factor (CDNF), that were tested in PD patients, focusing mainly on GDNF and CDNF. We summarize current possibilities of NP-mediated delivery of NTFs to the brain and discuss whether NPs have impact in improving the properties of NTFs and delivery across the BBB. Emerging delivery approaches and future directions of NTF-based nanomedicine are also discussed.

Surface charge, glycocalyx, and blood-brain barrier function

The negative surface charge of brain microvessel endothelial cells is derived from the special composition of their membrane lipids and the thick endothelial surface glycocalyx. They are important elements of the unique defense systems of the blood-brain barrier. The tissue-specific properties, components, function and charge of the brain endothelial glycocalyx have only been studied in detail in the past 15 years. This review highlights the importance of the negative surface charge in the permeability of macromolecules and nanoparticles as well as in drug interactions. We discuss surface charge and glycoxalyx changes in pathologies related to the brain microvasculature and protective measures against glycocalyx shedding and damage. We present biophysical techniques, including a microfluidic chip device, to measure surface charge of living brain endothelial cells and imaging methods for visualization of surface charge and glycocalyx.

Rethinking CRITID Procedure of Brain Targeting Drug Delivery: Circulation, Blood Brain Barrier Recognition, Intracellular Transport, Diseased Cell Targeting, Internalization, and Drug Release

The past decades have witnessed great progress in nanoparticle (NP)-based brain-targeting drug delivery systems, while their therapeutic potentials are yet to be fully exploited given that the majority of them are lost during the delivery process. Rational design of brain-targeting drug delivery systems requires a deep understanding of the entire delivery process along with the issues that they may encounter. Herein, this review first analyzes the typical delivery process of a systemically administrated NPs-based brain-targeting drug delivery system and proposes a six-step CRITID delivery cascade: circulation in systemic blood, recognizing receptor on blood-brain barrier (BBB), intracellular transport, diseased cell targeting after entering into parenchyma, internalization by diseased cells, and finally intracellular drug release. By dissecting the entire delivery process into six steps, this review seeks to provide a deep understanding of the issues that may restrict the delivery efficiency of brain-targeting drug delivery systems as well as the specific requirements that may guarantee minimal loss at each step. Currently developed strategies used for troubleshooting these issues are reviewed and some state-of-the-art design features meeting these requirements are highlighted. The CRITID delivery cascade can serve as a guideline for designing more efficient and specific brain-targeting drug delivery systems.

Multifaceted Therapy of Nanocatalysts in Neurological Diseases

With the development of enzymes immobilization technology and the discover of nanozymes, catalytic therapy exhibited tremendous potential for neurological diseases therapy. In especial, since the discovery of Fe₃O₄ nanoparticles possessing intrinsic peroxidase-like activity, various nanozymes have been developed and recently started to explore for neurological diseases therapy, such as Alzheimer's disease, Parkinson's disease and stroke. By combining the catalytic activities with other properties (such as optical, thermal, electrical, and magnetic properties) of nanomaterials, the multifunctional nanozymes would not only alleviate oxidative and nitrosative stress on the basis of multienzymes-mimicking activity, but also exert positive effects on immunization, inflammation, autophagy, protein aggregation, which provides the foundation for multifaceted treatments. This review will summarize various types of nanocatalysts and further provides a valuable discussion on multifaceted treatment by nanozymes for neurological diseases, which is anticipated to provide an easily accessible guide to the key opportunities and current challenges of the nanozymes-mediated treatments for neurological diseases.

Superparamagnetic iron oxide-gold nanoparticles conjugated with porous coordination cages: Towards controlled drug release for non-invasive neuroregeneration

This paper reports a smart intracellular nanocarrier for sustainable and controlled drug release in non-invasive neuroregeneration. The nanocarrier is composed by superparamagnetic iron oxide-gold (SPIO-Au) core-shell nanoparticles (NPs) conjugated with porous coordination cages (PCCs) through the thiol-containing molecules as bridges. The negatively charged PCC-2 and positively charged PCC-3 are compared for intracellular targeting. Both types result in intracellular targeting via direct penetration across cellular membranes. However, the pyrene (Py)-PEG-SH bridge enabled functionalization of SPIO-Au NPs with PCC-3 exhibits higher interaction with PC-12 neuron-like cells, compared with the rhodamine B (RhB)-PEG-SH bridge enabled case and the stand-alone SPIO-Au NPs. With neglectable toxicities to PC-12 cells, the proposed SPIO-Au-RhB(Py)-PCC-2(3) nanocarriers exhibit effective drug loading capacity of retinoic acid (RA) at 13.505 μg/mg of RA/NPs within 24 h. A controlled release of RA is achieved by using a low-intensity 525 nm LED light (100% compared to 40% for control group within 96 h).

Recent advances in nano delivery systems for blood-brain barrier (BBB) penetration and targeting of brain tumors

Gliomas constitute about 80% of brain tumors and have a meager two-year survival rate. The treatment options available are very few because of poor prognosis and a lack of targeted nanodelivery systems that can cross the blood-brain barrier (BBB) and the blood-tumor barrier. This short review attempts to clarify the challenges for delivery systems designed to cross the BBB, and provides a brief description of the different types of targeted nanodelivery system that have shown potential for success in delivering drugs to the brain. Further, this review describes the most recent studies that have developed nanoparticles for brain delivery in the past five years. We also provide an insight into the most recent clinical trials designed to assess the efficacy of these nanodelivery systems for glioma.

Thin platelet-like COF nanocomposites for blood brain barrier transport and inhibition of brain metastasis from renal cancer

Effective treatment of brain metastases is hindered by the blood-brain barrier (BBB) and the rapid development of resistance to drug therapy. Moreover, the clinical application of general formulations is hampered by biological barriers and biological elimination. To tackle this challenge, we report a feasible approach for the assembly of polymer-covalent organic framework (COF) nanocomposites into 150 nm thin platelets as a drug delivery vehicle for enhanced retention in brain tumours. Using intravital imaging, we demonstrate that these polymer-COF nanocomposites are able to traverse the BBB in mice and achieve direct tumour accumulation in intracranial orthotopic models of brain metastasis from renal cancer (BMRC). These nanocomposites can target brain tumour cells and respond to tumour microenvironmental characteristics, including acidic and redox conditions. Intracranial tumour acidity triggers the breakdown of the nanoassemblies to polymer-COF nanocomposites due to the presence of borate bonds. Furthermore, in vivo studies on the nanocomposites showed enhanced brain tumour-targeting efficiency and therapeutic effects compared to those of free-drug dosing. Mice treated with drug-loaded polymer-COF nanocomposites also show protection from systemic drug toxicity and improved survival, demonstrating the preclinical potential of this nanoscale platform to deliver novel combination therapies to BMRC and other central nervous system (CNS) tumours.

Network Pharmacology Analysis on Zhichan Powder in the Treatment of Parkinson's Disease

AIMS AND OBJECTIVE

Effective components and the mechanism of action of Zhichan powder for the treatment of Parkinson's disease were researched at a systematic level.

MATERIALS AND METHODS

Screening of active components in Zhichan powder for the treatment of Parkinson's disease was conducted using the Traditional Chinese Medicine Systems Pharmacology database, and a medicine-target-disease network was established with computational network pharmacology.

RESULTS

By using network pharmacology methods, we identified 18 major active components in Zhichan powder through screening, indicating a connection between chemical components of this Traditional Chinese Medicine and Parkinson's disease-related targets.

CONCLUSION

The medicine-target-disease system of Zhichan powder established by network pharmacology permitted visualization of clustering and differences among chemical components in this prescription, as well as the complex mechanism of molecular activities among those effective components, relevant targets, pathways, and the disease. Thus, our results provide a new perspective and method for revealing the mechanism of action of Traditional Chinese Medicine prescriptions.

Recent Advances in the Use of Lipid-Based Nanoparticles Against Glioblastoma Multiforme

Glioblastoma (GBM) is the most common and aggressive malignant brain tumor in adults. Although the overall incidence is less than 10 per 100,000 individuals, its poor prognosis and low survival rate make GBM a crucial public health issue. The main challenges for GBM treatment are related to tumor location and its complex and heterogeneous biology. In this sense, a broad range of nanoparticles with different sizes, architectures, and surface properties, have been engineered as brain drug delivery systems. Among them, lipid-based nanoparticles, such as liposomes, have been pointed out as promising materials to deliver antitumoral drugs to the central nervous system and thus, to improve brain drug targeting and therapeutic efficiency. Here, we describe the synthesis and general characteristics of lipid-based nanoparticles, as well as evidence in the past 5 years regarding their potential use to treat GBM.

Uptake of polymeric nanoparticles in a human induced pluripotent stem cell-based blood-brain barrier model: Impact of size, material, and protein corona

The blood-brain barrier (BBB) maintains the homeostasis of the central nervous system, which is one of the reasons for the treatments of brain disorders being challenging in nature. Nanoparticles (NPs) have been seen as potential drug delivery systems to the brain overcoming the tight barrier of endothelial cells. Using a BBB model system based on human induced pluripotent stem cells (iPSCs), the impact of polymeric nanoparticles has been studied in relation to nanoparticle size, material, and protein corona. PLGA [poly(lactic-co-glycolic acid)] and PLLA [poly(d,l-lactide)] nanoparticles stabilized with Tween® 80 were synthesized (50 and 100 nm). iPSCs were differentiated into human brain microvascular endothelial cells (hBMECs), which express prominent BBB features, and a tight barrier was established with a high transendothelial electrical resistance of up to 4000 Ω cm². The selective adsorption of proteins on the PLGA and PLLA nanoparticles resulted in a high percentage of apolipoproteins and complement components. In contrast to the prominently used BBB models based on animal or human cell lines, the present study demonstrates that the iPSC-based model is suited to study interactions with nanoparticles in correlation with their material, size, and protein corona composition. Furthermore, asymmetrical flow field-flow fractionation enables the investigation of size and agglomeration state of NPs in biological relevant media. Even though a similar composition of the protein corona has been detected on NP surfaces by mass spectrometry, and even though similar amounts of NP are interacting with hBMECs, 100 nm-sized PLGA NPs do impact the barrier, forming endothelial cells in an undiscovered manner.

Natural polymeric nanocarriers in malignant glioma drug delivery and targeting

Among all central nervous diseases, malignant glioma is a crucial part that deserves more attention since high fatality and disability rate. There are several therapeutic strategies applied to the treatment of malignant glioma, especially certain chemotherapy-related treatments. However, the existence of the blood-brain barrier (BBB) seriously hinders the strategy's progress, so how to escape from the barriers is a fascinating question. Herein, we comprehensively discussed the details of malignant glioma and the BBB's functional morphology and summarized several routes bypassing the BBB. Additionally, since possessing excellent properties for drug delivery, we provided an insight into various promising natural polymeric materials and highlighted their applications in the treatment of malignant glioma.

Synthesis of Double Interfering Biodegradable Nano-MgO Micelle Composites and Their Effect on Parkinson's Disease

Although gene therapy targeting the α-synuclein gene (SNCA) has achieved outstanding results in the treatment of Parkinson's disease (PD), the lack of a suitable gene delivery system and inadequate therapeutic effects remains a tremendous obstacle for RNAi therapy. Here, a degradable nano-MgO micelle composite (MgO(pDNA)-INS-Plu-mRNA-NGF) with double interference (mediated by RNAi and α-synuclein (α-syn)-targeted mRNA) was constructed. Binding mRNA treatment significantly increased the inhibitory effect compared to the reduction of α-syn expression by RNAi alone. Moreover, the cell experiments demonstrated that the viability of the PD cell model can be significantly improved by nano-MgO micelle composite treatment. More importantly, the composite has the ability to penetrate the blood brain barrier and deliver genes and mRNA to neurons through endocytosis mediated by the nerve growth factor and its receptors, thus significantly downregulating the expression of α-syn in the PD mice model without causing damage to other major organs. Overall, this work provides a novel insight into the design of biomaterials for gene therapy for PD.

Nanotechnology in the diagnosis and treatment of stroke

Increasing developments in the field of nanotechnology have ignited its use in stroke diagnosis and treatment. The benefits of structural modification, ease of synthesis, and biocompatibility support the use of nanomaterials in the clinic. The pathophysiology of stroke is complex, involving different brain regions; hence, therapeutic agents are required to be delivered to specific regions. Nanoparticles (NPs) can be engineered to help improve the delivery and release of therapeutic agents in a localized manner, especially in the penumbra. This contributes not only to therapy, but also to neurosurgery and neuroimaging. Nanomaterials also offer high efficacy with few adverse effects. In this review, we provide a concise summary of the caveats associated with nanotechnology with respect to stroke therapy and diagnosis.

Polysorbate-80 surface modified nano-stearylamine BQCA conjugate for the management of Alzheimer's disease

Acetylcholinesterase (AChE) inhibitors such as donepezil, galantamine and rivastigmine are used for the management of dementia in Alzheimer's Disease (AD). These drugs elevate endogenous acetylcholine (ACh) levels at the M1 muscarinic receptor in the brain to achieve therapeutic benefits. However, their side effects, such as nausea, vomiting, dizziness, insomnia, loss of appetite, altered heart rate, etc., are related to non-specific peripheral activation of M2-M5 muscarinic subtypes. It is logical, therefore, to develop drugs that selectively activate brain M1 receptors. Unfortunately, the orthosteric site homology among the receptor subtypes does not permit this approach. An alternative approach is to use positive allosteric modulator (PAM) of M1 receptors like benzyl quinolone carboxylic acid (BQCA). PAMs although devoid of M1 agonist activity, however, when bound, enhance the binding affinity of orthosteric ligand, Ach. The current challenge with PAMS is their low brain half-life, permeability, and higher elimination rates. This study reports active targeting of brain M1 receptors using surface modified nano lipid-drug conjugates (LDC) of M1 PAM, BQCA, to treat AD. Polysorbate-80 (P-80) surface modified stearylamine (SA)-BQCA conjugated nanoparticles (BQCA-SA-P80-NPs) were prepared by conjugating BQCA to SA, followed by the formation of nanoparticles (NPs) using P-80 by solvent injection method. The BQCA-SA-P80-NPs are near-spherical with a particle size (PS) of 166.62 ± 1.24 nm and zeta potential (ZP) of 23.59 ± 0.37 mV. In the in vitro cytotoxicity (SH-SY5Y cells) and hemolysis assays, BQCA-SA-P80-NPs, show acceptable safety and compatibility. In mice, Alzheimer's model, BQCA-SA-P80-NPs significantly prevent STZ induced changes in memory, neuronal Aβ1-42, p-Tau, APP, NF-κB, and BACE levels and neuronal cell death, when compared to untreated disease control and naïve BQCA treated group. Further, BQCA-SA-P80-NPs significantly improve the therapeutic efficacy of AChE inhibitor, donepezil (DPZ), indicating its potentiating effects. In vivo biodistribution studies in mice show selective accumulation of BQCA-SA-P80-NPs in the brain, suggesting an improved brain bioavailability and reduced peripheral side effects of BQCA. The study results demonstrate that BQCA-SA-P80-NPs can improve brain bioavailability and therapeutic efficacy of BQCA in AD.

A pentapeptide enabled AL3810 liposome-based glioma-targeted therapy with immune opsonic effect attenuated

AL3810, a molecular dual inhibitor of the vascular endothelial growth factor receptor (VEGFR) and fibroblast growth factor receptor (FGFR), has earned the permission of phase II clinical trial for tumor treatment by China FDA. As a reversible ATP-competitive inhibitor, AL3810 targets ATP-binding site on intracellular region of VEGFR and FGFR, whereas, AL3810 lacking interplay with extracellular region of receptors rendered deficient blood–brain tumor barrier (BBTB) recognition, poor brain penetration and unsatisfactory anti-glioma efficacy. Integrin αvβ3 overexpressed on capillary endothelial cells of BBTB as well as glioma cells illuminated ligand-modified liposomes for pinpoint spatial delivery into glioma. The widely accepted peptide c(RGDyK)-modified liposome loading AL3810 of multiple dosing caused hypothermia, activated anti-c(RGDyK)-liposome IgG and IgM antibody and pertinent complements C3b and C5b-9, and experienced complement-dependent opsonization. We newly proposed a pentapeptide mn with superb αvβ3-binding affinity and tailored AL3810-loaded mn-modified liposome that afforded impervious blood circulation, targeting ability, and glioma therapeutic expertise as vastly alleviated immune opsonization on the underpinning of the finite antibodies and complements assembly. Stemming from attenuated immunogenicity, peptide mn strengthened liposome functions as a promising nanocarrier platform for molecular targeting agents.

Microfluidic Isolation and Enrichment of Nanoparticles

Over the past decades, nanoparticles have increased in implementation to a variety of applications ranging from high-efficiency electronics to targeted drug delivery. Recently, microfluidic techniques have become an important tool to isolate and enrich populations of nanoparticles with uniform properties (e.g., size, shape, charge) due to their precision, versatility, and scalability. However, due to the large number of microfluidic techniques available, it can be challenging to identify the most suitable approach for isolating or enriching a nanoparticle of interest. In this review article, we survey microfluidic methods for nanoparticle isolation and enrichment based on their underlying mechanisms, including acoustofluidics, dielectrophoresis, filtration, deterministic lateral displacement, inertial microfluidics, optofluidics, electrophoresis, and affinity-based methods. We discuss the principles, applications, advantages, and limitations of each method. We also provide comparisons with bulk methods, perspectives for future developments and commercialization, and next-generation applications in chemistry, biology, and medicine.

Advancements in the Blood-Brain Barrier Penetrating Nanoplatforms for Brain Related Disease Diagnostics and Therapeutic Applications

Noninvasive treatments to treat the brain-related disorders have been paying more significant attention and it is an emerging topic. However, overcoming the blood brain barrier (BBB) is a key obstacle to most of the therapeutic drugs to enter into the brain tissue, which significantly results in lower accumulation of therapeutic drugs in the brain. Thus, administering the large quantity/doses of drugs raises more concerns of adverse side effects. Nanoparticle (NP)-mediated drug delivery systems are seen as potential means of enhancing drug transport across the BBB and to targeted brain tissue. These systems offer more accumulation of therapeutic drugs at the tumor site and prolong circulation time in the blood. In this review, we summarize the current knowledge and advancements on various nanoplatforms (NF) and discusses the use of nanoparticles for successful cross of BBB to treat the brain-related disorders such as brain tumors, Alzheimer's disease, Parkinson's disease, and stroke.

Antioxidant lipoic acid ligand-shell gold nanoconjugates against oxidative stress caused by α-synuclein aggregates

Gold nanoparticles are becoming a promising platform for the delivery of drugs to treat neurodegenerative diseases. Parkinson's disease, associated with the aggregation of α-synuclein, is a condition that results in dysfunctional neuronal cells leading to their degeneration and death. Oxidative stress has been strongly implicated as a common feature in this process. The limited efficacy of the traditional therapies and the development of associated severe side effects present an unmet need for preventive and adjuvant therapies. The organosulfur compound lipoic acid, naturally located in the mitochondria, plays a powerful antioxidative role against oxidative stress. However, the efficacy is limited by its low physiological concentration, and the administration is affected by its short half-life and bioavailability due to hepatic degradation. Here we exploited the drug delivery potential of gold nanoparticles to assemble lipoic acid, and administered the system into SH-SY5Y cells, a cellular model commonly used to study Parkinson's disease. We tested the nanoconjugates of GNPs-LA, under an oxidative environment induced by gold nanoparticle/α-synuclein conjugates (GNPs-α-Syn). GNPs-LA were found to be biocompatible and capable of restoring the cell damage caused by high-level reactive oxygen species generated by excessive oxidative stress in the cellular environment. We conclude that GNPs-LA may serve as promising drug delivery vehicles conveying antioxidant molecules for the treatment of Parkinson's disease.

Revisiting gene delivery to the brain: silencing and editing

Neurodegenerative disorders, ischemic brain diseases, and brain tumors are debilitating diseases that severely impact a person's life and could possibly lead to their demise if left untreated. Many of these diseases do not respond to small molecule therapeutics and have no effective long-term therapy. Gene therapy offers the promise of treatment or even a cure for both genetic and acquired brain diseases, mediated by either silencing or editing disease-specific genes. Indeed, in the last 5 years, significant progress has been made in the delivery of non-coding RNAs as well as gene-editing formulations to the brain. Unfortunately, the delivery is a major limiting factor for the success of gene therapies. Both viral and non-viral vectors have been used to deliver genetic information into a target cell, but they have limitations. Viral vectors provide excellent transduction efficiency but are associated with toxic effects and have limited packaging capacity; however, non-viral vectors are less toxic and show a high packaging capacity at the price of low transfection efficiency. Herein, we review the progress made in the field of brain gene therapy, particularly in the design of non-toxic and trackable non-viral vectors, capable of controlled release of genes in response to internal/external triggers, and in the delivery of formulations for gene editing. The application of these systems in the context of various brain diseases in pre-clinical and clinical tests will be discussed. Such promising approaches could potentially pave the way for clinical realization of brain gene therapies.

Nano-scaled materials may induce severe neurotoxicity upon chronic exposure to brain tissues: A critical appraisal and recent updates on predisposing factors, underlying mechanism, and future prospects

Owing to their tremendous potential, the inference of nano-scaled materials has revolutionized many fields including the medicine and health, particularly for development of various types of targeted drug delivery devices for early prognosis and successful treatment of various diseases, including the brain disorders. Owing to their unique characteristic features, a variety of nanomaterials (particularly, ultra-fine particles (UFPs) have shown tremendous success in achieving the prognostic and therapeutic goals for early prognosis and treatment of various brain maladies such as Alzheimer's disease, Parkinson's disease, brain lymphomas, and other ailments. However, serious attention is needful due to innumerable after-effects of the nanomaterials. Despite their immense contribution in optimizing the prognostic and therapeutic modalities, biological interaction of nanomaterials with various body tissues may produce severe nanotoxicity of different organs including the heart, liver, kidney, lungs, immune system, gastro-intestinal system, skin as well as nervous system. However, in this review, we have primarily focused on nanomaterials-induced neurotoxicity of the brain. Following their translocation into different regions of the brain, nanomaterials may induce neurotoxicity through multiple mechanisms including the oxidative stress, DNA damage, lysosomal dysfunction, inflammatory cascade, apoptosis, genotoxicity, and ultimately necrosis of neuronal cells. Our findings indicated that rigorous toxicological evaluations must be carried out prior to clinical translation of nanomaterials-based formulations to avoid serious neurotoxic complications, which may further lead to develop various neuro-degenerative disorders.

Personalized dynamic transport of magnetic nanorobots inside the brain vasculature

Delivering specific bioactive agents with sufficient bioavailability to the targeted brain area across blood brain barrier remains a big challenge. Magnetically driven nanorobots have demonstrated their potential for controlled drug delivery. However, the dynamic transport of these nanorobots inside each individual's brain vasculature is not yet well studied. Addressing this is a critical step forward to controlled drug delivery for non-invasive brain therapeutics. In this paper, we develop an analytical model describing the personalized dynamic transport of spherical magnetic nanorobots inside the brain vasculature reconstructed from the patient's angiography images. By inverting the transporting process, we first design the patient-specific transport path based on the reconstructed vascular model, and then calculate the magnetic force required to drive these nanorobots from the analytical model. Also, a finite element model is created to simulate the inverse design process, which implies that the delivery efficiency of these magnetically driven nanorobots to the targeted brain area can be increased by 20% and almost 95% nanorobots arrive at the desired vessel walls. In the end, a simplified brain vascular model is printed using PolyJet 3D 750 to demonstrate the dynamic transport of these nanorobots toward the targeted site. The proposed theoretical modeling, numerical simulation and experimental validation lay solid foundation toward non-invasive brain therapeutics with maximal accuracy and minimal side effects.

Engineering the drug carrier biointerface to overcome biological barriers to drug delivery

Micro and nanoscale drug carriers must navigate through a plethora of dynamic biological systems prior to reaching their tissue or disease targets. The biological obstacles to drug delivery come in many forms and include tissue barriers, mucus and bacterial biofilm hydrogels, the immune system, and cellular uptake and intracellular trafficking. The biointerface of drug carriers influences how these carriers navigate and overcome biological barriers for successful drug delivery. In this review, we examine how key material design parameters lead to dynamic biointerfaces and improved drug delivery across biological barriers. We provide a brief overview of approaches used to engineer key physicochemical properties of drug carriers, such as morphology, surface chemistry, and topography, as well as the development of dynamic responsive materials for barrier navigation. We then discuss essential biological barriers and how biointerface engineering can enable drug carriers to better navigate and overcome these barriers to drug delivery.

In vivo Bio-Distribution and Toxicity Evaluation of Polymeric and Lipid-Based Nanoparticles: A Potential Approach for Chronic Diseases Treatment

INTRODUCTION

Nanoparticles (NPs), as drug delivery systems, appear to be a promising tool for prolonged therapeutic strategies as they allow a controlled drug release over time. However, most of the studies found in the literature simply contemplate the use of a single or low number of dosages with low NPs concentrations. In the context of chronic diseases, like Alzheimer's disease, cancer or human immunodeficiency virus (HIV), where the therapeutic scheme is also chronic, studies with numerous repeated dosages are often neglected.

METHODS

We screened different NPs, polymeric and lipid-based, in a repeated-dose toxicity study, to evaluate the safety and tissue distribution of promising nanocarriers to be used in the treatment of long-lasting diseases.

RESULTS

After administrating 24 high concentrated doses of the selected NPs intraperitoneally (i.p.) (3 times a week for 2 months), animals have presented NPs accumulation in different tissues. However, neither toxicity, bodyweight changes nor clinical signs of disease were observed.

DISCUSSION

This work demonstrates no general adverse effects upon the studied NPs repeated-dose exposure, indicating the most promising NPs to be used in the different therapeutic circumstances, which may be useful in chronic diseases treatment.

Glycosylated-imidazole aldoximes as reactivators of pesticides inhibited AChE: Synthesis and in-vitro reactivation study

The present armamentarium of commercially available antidotes provides limited protection against the neurological effects of organophosphate exposure. Hence, there is an urgent need to design and develop molecules that can protect and reactivate inhibited-AChE in the central nervous system. Some natural compounds like glucose and certain amino acids (glutamate, the anion of glutamic acid) can easily cross the blood brain barrier although they are highly polar. Glucose is mainly transported by systems like glucose transporter protein type 1 (GLUT1). For this reason, a series of non-quaternary and quaternary glycosylated imidazolium oximes with different alkane linkers have been designed and synthesized. These compounds were evaluated for their in-vitro reactivation ability against pesticide (paraoxon-ethyl and paraoxon-methyl) inhibited-AChE and compared with standards antidote AChE reactivators pralidoxime and obidoxime. Several physicochemical properties including acid dissociation constant (pK_a), logP, logD, HBD and HBA, have also been assessed for reported compounds. Out of the synthesized compounds, three have exhibited comparable potency with a standard antidote (pralidoxime).

Use of Biodegradable, Chitosan-Based Nanoparticles in the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that affects more than 24 million people worldwide and represents an immense medical, social and economic burden. While a vast array of active pharmaceutical ingredients (API) is available for the prevention and possibly treatment of AD, applicability is limited by the selective nature of the blood-brain barrier (BBB) as well as by their severe peripheral side effects. A promising solution to these problems is the incorporation of anti-Alzheimer drugs in polymeric nanoparticles (NPs). However, while several polymeric NPs are nontoxic and biocompatible, many of them are not biodegradable and thus not appropriate for CNS-targeting. Among polymeric nanocarriers, chitosan-based NPs emerge as biodegradable yet stable vehicles for the delivery of CNS medications. Furthermore, due to their mucoadhesive character and intrinsic bioactivity, chitosan NPs can not only promote brain penetration of drugs via the olfactory route, but also act as anti-Alzheimer therapeutics themselves. Here we review how chitosan-based NPs could be used to address current challenges in the treatment of AD; with a specific focus on the enhancement of blood-brain barrier penetration of anti-Alzheimer drugs and on the reduction of their peripheral side effects.

Targeted drug therapy in nonsmall cell lung cancer: clinical significance and possible solutions-part II (role of nanocarriers)

INTRODUCTION

Nonsmall cell lung cancer (NSCLC) accounts for 80-85% of the cases of lung cancer. The conventional therapeutic effective dosage forms used to treat NSCLC are associated with rigid administration schedules, adverse effects, and may be associated with acquired resistance to therapy. Nanocarriers may provide a suitable alternative to regular formulations to overcome inherent drawbacks and provide better treatment modalities for the patient.

AREAS COVERED

The article explores the application of drug loaded nanocarriers for lung cancer treatment. Drug-loaded nanocarriers can be modified to achieve controlled delivery at the desired tumor infested site. The type of nanocarriers employed are diverse based on polymers, liposomes, metals and a combination of two or more different base materials (hybrids). These may be designed for systemic delivery or local delivery to the lung compartment (via inhalation).

EXPERT OPINION

Nanocarriers can improve pharmacokinetics of the drug payload by improving its delivery to the desired location and can reduce associated systemic toxicities. Through nanocarriers, a wide variety of therapeutics can be administered and targeted to the cancerous site. Some examples of the utilities of nanocarriers are codelivery of drugs, gene delivery, and delivery of other biologics. Overall, the nanocarriers have promising potential in improving therapeutic efficacy of drugs used in NSCLC.

The Blood-Brain Barrier Cell-Targeted Gene Delivery System to Enhance Nerve Growth Factor Protein Secretion in the Brain

The enhanced permeability efficiencies still remain a big challenge in crossing the blood-brain barrier (BBB). Herein, a BBB-targeting delivery system based on transferrin (Tf)-poly(ethylene glycol) (PEG) PEGylated-cationic liposome was prepared for delivering the protamine labeled nerve growth factor (NGF) gene. The nanoparticle (TLDP) could preferentially accumulate into the BBB by receptor-mediated transcytosis via the Tf receptor present on cerebral endothelial cells. The polyplex showed good encapsulation of the NGF gene as well as triggered corresponding protein release in the BBB. Surface modification of liposomes with PEG imparts a steric barrier to the NPs that decreases their recognition and clearance by the reticuloendothelial system for increasing the circulation time, and cationic liposomes with protamine are indicated with nuclear localization function to improve the efficiency of nucleus localization and gene expression. The polyplex at a DOTAP/DNA ratio of 3 showed an appropriate diameter, desired serum stability, and much higher encapsulation efficiency. The polyplex had no cytotoxicity against cells. The cell uptake of the TLDP was stronger than other groups without transferrin, which suggested that the TLDP could successfully deliver the NGF gene to the BBB cell and enhanced the expression and secretion of the NGF protein in the brain. In vivo imaging further verified that the TLDP exhibited a higher brain distribution than other groups. Consequently, these findings showed that BBB cells as the "transit station" is a promising method to overcome the BBB and increase the concentration of drug in the brain.

Functionalized PLGA nanoparticles prepared by nano-emulsion templating interact selectively with proteins involved in the transport through the blood-brain barrier

During the last few decades, extensive efforts has been made to design nanocarriers to transport drugs into the central nervous system (CNS). However, its efficacy is limited due to the presence of the Blood-Brain Barrier (BBB) which greatly reduces drug penetration making Drug Delivery Systems (DDS) necessary. Polymeric nanoparticles (NPs) have been reported to be appropriate for this purpose and in particular, poly(lactic-co-glycolic acid) (PLGA) has been used for its ability to entrap small molecule drugs with great efficiency and the ease with which it functionalizes NPs. Despite the fact that their synthetic identity has been studied in depth, the biological identity of such manufactured polymers still remains unknown as does their biodistribution and in vivo fate. This biological identity is a result of their interaction with blood proteins, the so-called "protein corona" which tends to alter the behavior of polymeric nanoparticles in the body. The aim of the present research is to identify the proteins bounded to polymeric nanoparticles designed to selectively interact with the BBB. For this purpose, four different PLGA NPs were prepared and analyzed: (i) "PLGA@Drug," in which a model drug was encapsulated in its core; (ii) "8D3-PLGA" NPs where the PLGA surface was functionalized with a monoclonal anti-transferrin receptor antibody (8D3 mAb) in order to specifically target the BBB; (iii) "8D3-PLGA@Drug" in which the PLGA@Drug surface was functionalized using the same antibody described above and (iv) bare PLGA NPs which were used as a control. Once the anticipated protein corona NPs were obtained, proteins decorating both bare and functionalized PLGA NPs were isolated and analyzed. Apart from the indistinct interaction with PLGA NPs with the most abundant serum proteins, specific proteins could also be identified in the case of functionalized PLGA NPs. These findings may provide valuable insight into designing novel vehicles based on PLGA NPs for crossing the BBB.

Nanoparticle-microglial interaction in the ischemic brain is modulated by injury duration and treatment

Cerebral ischemia is a major cause of death in both neonates and adults, and currently has no cure. Nanotechnology represents one promising area of therapeutic development for cerebral ischemia due to the ability of nanoparticles to overcome biological barriers in the brain. ex vivo injury models have emerged as a high-throughput alternative that can recapitulate disease processes and enable nanoscale probing of the brain microenvironment. In this study, we used oxygen-glucose deprivation (OGD) to model ischemic injury and studied nanoparticle interaction with microglia, resident immune cells in the brain that are of increasing interest for therapeutic delivery. By measuring cell death and glutathione production, we evaluated the effect of OGD exposure time and treatment with azithromycin (AZ) on slice health. We found a robust injury response with 0.5 hr of OGD exposure and effective treatment after immediate application of AZ. We observed an OGD-induced shift in microglial morphology toward increased heterogeneity and circularity, and a decrease in microglial number, which was reversed after treatment. OGD enhanced diffusion of polystyrene-poly(ethylene glycol) (PS-PEG) nanoparticles, improving transport and ability to reach target cells. While microglial uptake of dendrimers or quantum dots (QDs) was not enhanced after injury, internalization of PS-PEG was significantly increased. For PS-PEG, AZ treatment restored microglial uptake to normal control levels. Our results suggest that different nanoparticle platforms should be carefully screened before application and upon doing so; disease-mediated changes in the brain microenvironment can be leveraged by nanoscale drug delivery devices for enhanced cell interaction.