Gold Nanoparticles for Brain Tumor Imaging: A Systematic Review

Drug-Loaded Mitochondrial Targeted Nanoparticles for Tumor Imaging and PDT/PTT Combined Chemotherapy in Muscle-Invasive Bladder Cancer

Neoadjuvant chemotherapy combined with radical cystectomy is the standard treatment for muscle-invasive bladder cancer (MIBC). While cisplatin-based regimens reduce postoperative recurrence, their severe toxicity often limits clinical application. Moreover, the need for urinary diversion after radical cystectomy significantly impacts quality of life, leading to reluctance toward surgery. Therefore, developing tumor-targeted therapies and alternative treatment strategies for MIBC is of great clinical significance. In this study, the IR780 iodide multifunctional dye is conjugated to alginate polysaccharide and developed a novel cisplatin-loaded nanoparticle. Then, the tumor targeting and antitumor effects of the nanoparticles are evaluated in vitro and in vivo. The results show that the nanoparticles have sufficient drug loading, enhanced tumor targeting, and good photothermal effect. Furthermore, they shows potential for tumor imaging and diagnostic applications in a mouse model of MIBC. This study proposes a potentially effective treatment for MIBC by combining near-infrared localized phototherapy with systemic chemotherapy to eliminate malignant tissue.

The utilisation of fMRI for pre-operative mapping in the paediatric population with central nervous system tumours: a systematic review

BACKGROUND

Functional MRI (fMRI) is a well-established tool for pre-operative planning, providing neurosurgeons with a roadmap of critical functional areas to preserve during surgery. Despite its increasing use, there is a need to compare task-based (tb-fMRI) and resting-state fMRI (rs-fMRI) in the peadiatric population to comprehensively evaluate the existing literature on the use of fMRI for pre-operative mapping in pediatric patients, comparing tb-fMRI and rs-fMRI.

METHODS

Two databases were searched for relevant studies published before July 2024 following the PRISMA guidelines. Eleven studies were selected and comprised 431 participants: 377 patients with different types and locations of brain tumours, and 54 healthy controls (HC).

RESULTS

Results indicate that tb-fMRI could reliably locate the eloquent cortex with more than an 80% success rate. Furthermore, results were comparable with intraoperative mapping. Two studies reported that 68-81% of patients did not develop deficits in the postoperative period. Results also found that rs-fMRI can fill the gap in the situation of paediatric patients when other techniques do not apply to younger patients.

CONCLUSION

This study suggests that tb-fMRI is more effective for pre-operative mapping in pediatric patients, offering precise localisation of critical brain functions and enhancing surgical planning. Although rs-fMRI is less demanding and compatible with light sedation, it lacks the specificity needed for accurate identification of language, sensory, and motor areas, which limits its clinical relevance. rs-fMRI can aid in function-preserving treatments for brain tumour patients and reduce the need for invasive procedures. Combining tb-fMRI with intraoperative mapping optimizes precision and safety in pediatric-neurosurgery.

Innovative applications of advanced nanomaterials in cerebrovascular imaging

Cerebrovascular imaging is essential for the diagnosis, treatment, and prognosis of cerebrovascular disease, including stroke, aneurysms, and vascular malformations. Conventional imaging techniques such as MRI, CT, DSA and ultrasound have their own strengths and limitations, particularly in terms of resolution, contrast and safety. Recent advances in nanotechnology offer new opportunities for improved cerebrovascular imaging. Nanomaterials, including metallic nanoparticles, magnetic nanoparticles, quantum dots, carbon-based nanomaterials, and polymer nanoparticles, show great potential due to their unique physical, chemical, and biological properties. This review summarizes recent advances in advanced nanomaterials for cerebrovascular imaging and their applications in various imaging techniques, and discusses challenges and future research directions. The aim is to provide valuable insights for researchers to facilitate the development and clinical application of these innovative nanomaterials in cerebrovascular imaging.

A review on the role of nanoparticles for targeted brain drug delivery: synthesis, characterization, and applications

Unfortunately, nowadays, brain disorders, which include both neurological and mental disorders, are the main cause of years spent living with a disability worldwide. There are serious diseases with a high prevalence and a high mortality rate. However, the outmoded technical infrastructure makes their treatment difficult. The blood-brain barrier (BBB) serves as a protective mechanism for the central nervous system (CNS) and regulates its homeostatic processes. The brain is protected against injury and illness by an extremely complex system that precisely regulates the flow of ions, very few tiny molecules, and an even smaller number of macromolecules from the blood to the brain. Nevertheless, the BBB also considerably inhibits the delivery of medications to the brain, making it impossible to treat a variety of neurological diseases. Several strategies are now being studied to enhance the transport of drugs over the BBB. According to this research, nanoparticles are one of the most promising agents for brain disease treatment while many conventional drugs are also capable of crossing this barrier but there are amazing facts about nanoparticles in brain drug delivery. For example, 1. Precision Targeting: Through mechanisms such as receptor-mediated transport, ligand attachment, or the use of external stimuli (e.g., magnetic or thermal guidance), nanoparticles can deliver drugs specifically to diseased areas of the brain while minimizing exposure to healthy tissues. This targeted approach reduces side effects and enhances therapeutic outcomes. 2. Improved Drug Stability: Drugs can be encapsulated by nanoparticles, which keeps them stable and shields them from deterioration while being transported to the brain. 3. Therapeutic Payload: Nanoparticles possess a high surface-area-to-volume ratio, enabling them to encapsulate a substantial quantity of therapeutic agents relative to their size. This allows for enhanced drug delivery efficiency, maximizing therapeutic outcomes while potentially reducing the required dosage to achieve the desired effect. 4. Imaging Properties: Certain nanoparticles can also act as contrast agents for magnetic resonance imaging (MRI), allowing for the real-time visualization of drug distribution and administration in the brain. 5. Combination Therapy Possibility: Nanoparticles can be designed to co-deliver multiple medications or therapeutic agents, which could enhance synergistic effects. There have been in vivo studies where nanoparticles were successfully used for combination therapies, demonstrating potential for personalized treatments. One notable example is in cancer treatment, where nanoparticles have been designed to co-deliver multiple chemotherapeutic agents. In general, brain medication delivery by nanoparticles is a novel strategy that has the potential to revolutionize neurological disease therapy and enhance patient outcomes. The study furthermore includes a concise depiction of the structural and physiological characteristics of the BBB, and it also provides an overview of the nanoparticles that are most often used in medicine. A brief overview of the structural and physiochemical characteristics of the NPs, as well as the most popular nanoparticles used in medicine, is also included in the review.

Unlocking the potential of RGD-conjugated gold nanoparticles: a new frontier in targeted cancer therapy, imaging, and metastasis inhibition

In the rapidly evolving field of cancer therapeutics, the potential of gold nanoparticles (AuNPs) conjugated with RGD peptides has emerged as a promising avenue for targeted therapy and imaging. Despite numerous studies demonstrating the effectiveness of RGD-conjugated AuNPs in specifically targeting tumor cells and enhancing radiation therapy (RT), a comprehensive review of these advancements is currently lacking. This review aims to fill this critical gap in the literature. Our analysis reveals that RGD-conjugated AuNPs have shown significant promise in improving the diagnosis and treatment of various types of cancer, including breast cancer. However, the full potential of this technology is yet to be realized. The development of multifunctional nanoplatforms incorporating AuNPs has opened new horizons for targeted therapy, dual-mode imaging, and inhibition of tumor growth and metastasis. This review is of paramount importance as it provides a comprehensive overview of the current state of research in this area, and highlights the areas where further research is needed. It is hoped that this review will inspire further investigations into this promising nanotechnology, ultimately leading to improved cancer diagnosis and therapy. Therefore, the findings presented in this review underscore the potential of AuNPs conjugated with RGD peptides as a revolutionary approach in cancer therapeutics. It is our fervent hope that this review will serve as a catalyst for further research in this exciting field.

Nano-based approaches for the treatment of neuro-immunological disorders: a special emphasis on multiple sclerosis

Multiple sclerosis (MS) is a neuroimmunological disorder which causes axonal damage, demyelination and paralysis. Although numerous therapeutics have been developed for the effective treatment of MS and a few have been approved in recent decades, complete remission and treatment of MS remain a matter of concern. Nanotechnology is a potential approach for manipulating the properties of materials at the molecular level to attain desired properties. This approach is effective in the treatment of several CNS disorders by enhancing drug delivery, bioavailability and efficacy. We have briefly discussed the neuroimmunological disorders with a particular emphasis on MS. We also explored nanoengineered drug delivery systems, describing several nano-formulations for the treatment of MS, challenges and future of nanotechnology.

Capped Plasmonic Gold and Silver Nanoparticles with Porphyrins for Potential Use as Anticancer Agents-A Review

Photothermal therapy (PTT) and photodynamic therapy (PDT) are potential cancer treatment methods that are minimally invasive with high specificity for malignant cells. Emerging research has concentrated on the application of metal nanoparticles encapsulated in porphyrin and their derivatives to improve the efficacy of these treatments. Gold and silver nanoparticles have distinct optical properties and biocompatibility, which makes them efficient materials for PDT and PTT. Conjugation of these nanoparticles with porphyrin derivatives increases their light absorption and singlet oxygen generation that create a synergistic effect that increases phototoxicity against cancer cells. Porphyrin encapsulation with gold or silver nanoparticles improves their solubility, stability, and targeted tumor delivery. This paper provides comprehensive review on the design, functionalization, and uses of plasmonic silver and gold nanoparticles in biomedicine and how they can be conjugated with porphyrins for synergistic therapeutic effects. Furthermore, it investigates this dual-modal therapy's potential advantages and disadvantages and offers perspectives for future prospects. The possibility of developing gold, silver, and porphyrin nanotechnology-enabled biomedicine for combination therapy is also examined.

Surface-Enhanced Raman Scattering Nanosensing and Imaging in Neuroscience

Monitoring neurochemicals and imaging the molecular content of brain tissues in vitro, ex vivo, and in vivo is essential for enhancing our understanding of neurochemistry and the causes of brain disorders. This review explores the potential applications of surface-enhanced Raman scattering (SERS) nanosensors in neurosciences, where their adoption could lead to significant progress in the field. These applications encompass detecting neurotransmitters or brain disorders biomarkers in biofluids with SERS nanosensors, and imaging normal and pathological brain tissues with SERS labeling. Specific studies highlighting in vitro, ex vivo, and in vivo analysis of brain disorders using fit-for-purpose SERS nanosensors will be detailed, with an emphasis on the ability of SERS to detect clinically pertinent levels of neurochemicals. Recent advancements in designing SERS-active nanomaterials, improving experimentation in biofluids, and increasing the usage of machine learning for interpreting SERS spectra will also be discussed. Furthermore, we will address the tagging of tissues presenting pathologies with nanoparticles for SERS imaging, a burgeoning domain of neuroscience that has been demonstrated to be effective in guiding tumor removal during brain surgery. The review also explores future research applications for SERS nanosensors in neuroscience, including monitoring neurochemistry in vivo with greater penetration using surface-enhanced spatially offset Raman scattering (SESORS), near-infrared lasers, and 2-photon techniques. The article concludes by discussing the potential of SERS for investigating the effectiveness of therapies for brain disorders and for integrating conventional neurochemistry techniques with SERS sensing.

Advanced manufacturing of nanoparticle formulations of drugs and biologics using microfluidics

Numerous innovative nanoparticle formulations of drugs and biologics, named nano-formulations, have been developed in the last two decades. However, methods for their scaled-up production are still lagging, as the amount needed for large animal tests and clinical trials is typically orders of magnitude larger. This manufacturing challenge poses a critical barrier to successfully translating various nano-formulations. This review focuses on how microfluidics technology has become a powerful tool to overcome this challenge by synthesizing various nano-formulations with improved particle properties and product purity in large quantities. This microfluidic-based manufacturing is enabled by microfluidic mixing, which is capable of the precise and continuous control of the synthesis of nano-formulations. We further discuss the specific applications of hydrodynamic flow focusing, a staggered herringbone micromixer, a T-junction mixer, a micro-droplet generator, and a glass capillary on various types of nano-formulations of polymeric, lipid, inorganic, and nanocrystals. Various separation and purification microfluidic methods to enhance the product purity are reviewed, including acoustofluidics, hydrodynamics, and dielectrophoresis. We further discuss the challenges of microfluidics being used by broader research and industrial communities. We also provide future outlooks of its enormous potential as a decentralized approach for manufacturing nano-formulations.

Progress and Challenges in the Diagnosis and Treatment of Brain Cancer Using Nanotechnology

Primary brain cancer or brain cancer is the overgrowth of abnormal or malignant cells in the brain or its nearby tissues that form unwanted masses called brain tumors. People with malignant brain tumors suffer a lot, and the expected life span of the patients after diagnosis is often only around 14 months, even with the most vigorous therapies. The blood-brain barrier (BBB) is the main barrier in the body that restricts the entry of potential chemotherapeutic agents into the brain. The chances of treatment failure or low therapeutic effects are some significant drawbacks of conventional treatment methods. However, recent advancements in nanotechnology have generated hope in cancer treatment. Nanotechnology has shown a vital role starting from the early detection, diagnosis, and treatment of cancer. These tiny nanomaterials have great potential to deliver drugs across the BBB. Beyond just drug delivery, nanomaterials can be simulated to generate fluorescence to detect tumors. The current Review discusses in detail the challenges of brain cancer treatment and the application of nanotechnology to overcome those challenges. The success of chemotherapeutic treatment or the surgical removal of tumors requires proper imaging. Nanomaterials can provide imaging and therapeutic benefits for cancer. The application of nanomaterials in the diagnosis and treatment of brain cancer is discussed in detail by reviewing past studies.

Recent Advancements in Nanomaterials: A Promising Way to Manage Neurodegenerative Disorders

Neurodegenerative diseases (NDs) such as dementia, Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and amyotrophic lateral sclerosis are some of the most prevalent disorders currently afflicting healthcare systems. Many of these diseases share similar pathological hallmarks, including elevated oxidative stress, mitochondrial dysfunction, protein misfolding, excitotoxicity, and neuroinflammation, all of which contribute to the deterioration of the nervous system's structure and function. The development of diagnostic and therapeutic materials in the monitoring and treatment of these diseases remains challenging. One of the biggest challenges facing therapeutic and diagnostic materials is the blood-brain barrier (BBB). The BBB is a multifunctional membrane possessing a plethora of biochemical, cellular, and immunological features that ensure brain homeostasis by preventing the entry and accumulation of unwanted compounds. With regards to neurodegenerative diseases, the recent application of tailored nanomaterials (nanocarriers and nanoparticles) has led to advances in diagnostics and therapeutics. In this review, we provide an overview of commonly used nanoparticles and their applications in NDs, which may offer new therapeutic strategies for the prevention and treatment of neurodegenerative diseases.

Curcumin-reduced gold nanoparticles facilitate IL-12 delivery to a cervical cancer in vitro cell model

Aim: To synthesize curcumin-reduced gold nanoparticles (AuNPs) for the efficient delivery to and expression of the IL-12 gene in cervical cancer (HeLa) cells in vitro. Methods: Curcumin-reduced AuNPs were synthesized, stabilized with poly-L-lysine and PEG, conjugated to IL-12 DNA and physicochemically characterized. Cytotoxicity and IL-12 expression were accessed in vitro. Results & discussion: Stable, spherical AuNPs effectively compacted and protected the IL-12 DNA and tolerated well in vitro. Real-time quantitative PCR and ELISA confirmed the successful delivery and expression of the IL-12 gene in HeLa cells. Conclusion: The favorable attributes of this AuNP-delivery system and the significant IL-12 expression obtained augur well for cytokine-based therapy or immunotherapy in cervical cancer.

Nanoparticle-Based Drug Delivery Systems: An Inspiring Therapeutic Strategy for Neurodegenerative Diseases

Neurodegenerative diseases are common, incurable neurological disorders with high prevalence, and lead to memory, movement, language, and intelligence impairments, threatening the lives and health of patients worldwide. The blood-brain barrier (BBB), a physiological barrier between the central nervous system and peripheral blood circulation, plays an important role in maintaining the homeostasis of the intracerebral environment by strictly regulating the transport of substances between the blood and brain. Therefore, it is difficult for therapeutic drugs to penetrate the BBB and reach the brain, and this affects their efficacy. Nanoparticles (NPs) can be used as drug transport carriers and are also known as nanoparticle-based drug delivery systems (NDDSs). These systems not only increase the stability of drugs but also facilitate the crossing of drugs through the BBB and improve their efficacy. In this article, we provided an overview of the types and administration routes of NPs, highlighted the preclinical and clinical studies of NDDSs in neurodegenerative diseases, and summarized the combined therapeutic strategies in the management of neurodegenerative diseases. Finally, the prospects and challenges of NDDSs in recent basic and clinical research were also discussed. Above all, NDDSs provide an inspiring therapeutic strategy for the treatment of neurodegenerative diseases.

Nanoparticles for Drug and Gene Delivery in Pediatric Brain Tumors' Cancer Stem Cells: Current Knowledge and Future Perspectives

Primary malignant brain tumors are the most common solid neoplasm in childhood. Despite recent advances, many children affected by aggressive or metastatic brain tumors still present poor prognosis, therefore the development of more effective therapies is urgent. Cancer stem cells (CSCs) have been discovered and isolated in both pediatric and adult patients with brain tumors (e.g., medulloblastoma, gliomas and ependymoma). CSCs are a small clonal population of cancer cells responsible for brain tumor initiation, maintenance and progression, displaying resistance to conventional anticancer therapies. CSCs are characterized by a specific repertoire of surface markers and intracellular specific pathways. These unique features of CSCs biology offer the opportunity to build therapeutic approaches to specifically target these cells in the complex tumor bulk. Treatment of pediatric brain tumors with classical chemotherapeutic regimen poses challenges both for tumor location and for the presence of the blood-brain barrier (BBB). Lastly, the application of chemotherapy to a developing brain is followed by long-term sequelae, especially on cognitive abilities. Novel avenues are emerging in the therapeutic panorama taking advantage of nanomedicine. In this review we will summarize nanoparticle-based approaches and the efficacy that NPs have intrinsically demonstrated and how they are also decorated by biomolecules. Furthermore, we propose novel cargoes together with recent advances in nanoparticle design/synthesis with the final aim to specifically target the insidious CSCs population in the tumor bulk.

Advanced Nanotechnology Approaches as Emerging Tools in Cellular-Based Technologies

Stem cells are valuable tools in regenerative medicine because they can generate a wide variety of cell types and tissues that can be used to treat or replace damaged tissues and organs. However, challenges related to the application of stem cells in the scope of regenerative medicine have urged scientists to utilize nanomedicine as a prerequisite to circumvent some of these hurdles. Nanomedicine plays a crucial role in this process and manipulates surface biology, the fate of stem cells, and biomaterials. Many attempts have been made to modify cellular behavior and improve their regenerative ability using nano-based strategies. Notably, nanotechnology applications in regenerative medicine and cellular therapies are controversial because of ethical and legal considerations. Therefore, this review describes nanotechnology in cell-based applications and focuses on newly proposed nano-based approaches. Cutting-edge strategies to engineer biological tissues and the ethical, legal, and social considerations of nanotechnology in regenerative nanomedicine applications are also discussed.

Strategies to overcome/penetrate the BBB for systemic nanoparticle delivery to the brain/brain tumor

Despite its prevalence in the management of peripheral tumors, compared to surgery and radiation therapy, chemotherapy is still a suboptimal intervention in fighting against brain cancer and cancer brain metastases. This discrepancy is mainly derived from the complicatedly physiological characteristic of intracranial tumors, including the presence of blood-brain barrier (BBB) and limited enhanced permeability and retention (EPR) effect attributed to blood-brain tumor barrier (BBTB), which largely lead to insufficient therapeutics penetrating to tumor lesions to produce pharmacological effects. Therefore, dependable methodologies that can boost the efficacy of chemotherapy for brain tumors are urgently needed. Recently, nanomedicines have shown great therapeutic potential in brain tumors by employing various transcellular strategies, paracellular strategies, and their hybrids, such as adsorptive-mediated transcytosis, receptor-mediated transcytosis, BBB disruption technology, and so on. It is compulsory to comprehensively summarize these practices to shed light on future directions in developing therapeutic regimens for brain tumors. In this review, the biological and pathological characteristics of brain tumors, including BBB and BBTB, are illustrated. After that, the emerging delivery strategies for brain tumor management are summarized into different classifications and supported with detailed examples. Finally, the potential challenges and prospects for developing and clinical application of brain tumor-oriented nanomedicine are discussed.

Overcoming the blood-brain barrier for the therapy of malignant brain tumor: current status and prospects of drug delivery approaches

Besides the broad development of nanotechnological approaches for cancer diagnosis and therapy, currently, there is no significant progress in the treatment of different types of brain tumors. Therapeutic molecules crossing the blood-brain barrier (BBB) and reaching an appropriate targeting ability remain the key challenges. Many invasive and non-invasive methods, and various types of nanocarriers and their hybrids have been widely explored for brain tumor treatment. However, unfortunately, no crucial clinical translations were observed to date. In particular, chemotherapy and surgery remain the main methods for the therapy of brain tumors. Exploring the mechanisms of the BBB penetration in detail and investigating advanced drug delivery platforms are the key factors that could bring us closer to understanding the development of effective therapy against brain tumors. In this review, we discuss the most relevant aspects of the BBB penetration mechanisms, observing both invasive and non-invasive methods of drug delivery. We also review the recent progress in the development of functional drug delivery platforms, from viruses to cell-based vehicles, for brain tumor therapy. The destructive potential of chemotherapeutic drugs delivered to the brain tumor is also considered. This review then summarizes the existing challenges and future prospects in the use of drug delivery platforms for the treatment of brain tumors.

Secondary Electrons in Gold Nanoparticle Clusters and Their Role in Therapeutic Ratio: The Outcome of a Monte Carlo Simulation Study

Gold nanoparticles (GNPs) are used in proton therapy radio-sensitizers to help increase the dose of radiation to targeted tumors by the emission of secondary electrons. Thus, this study aimed to investigate the link between secondary electron yields produced from a nanoshell of GNPs and dose absorption according to the distance from the center of the nanoparticles by using a Monte Carlo model. Microscopic evaluation was performed by modeling the interactions of secondary electrons in a phase-space file (PSF), where the number of emitted electrons was calculated within a spherical GNP of 15 nm along with the absorbed dose near it. Then, the Geant4-DNA physics list was used to facilitate the tracking of low-energy electrons down to an energy below 50 eV in water. The results show a remarkable change in the number of secondary electrons, which can be compared at concentrations less than and greater than 5 mg/mL, with increased secondary electron production exhibited around NPs within a distance of 10–100 nm from the surface of all nanospheres. It was found that there was a steep dose enhancement drop-off up to a factor of dose enhancement factor (DFE) ≤ 1 within a short distance of 100 nm from the surface of the GNPs, which revealed that the dose enhancement existed locally at nanometer distances from the GNPs. Overall, our results indicate that the physical interactions of protons with GNP clusters should not be considered as being directly responsible for the radio-sensitization effect, but should be regarded as playing a major role in NP properties and concentrations, which has a subsequent impact on local dose enhancement.

Monodisperse Gold Nanoparticles: A Review on Synthesis and Their Application in Modern Medicine

Gold nanoparticles (AuNPs) are becoming increasingly popular as drug carriers due to their unique properties such as size tenability, multivalency, low toxicity and biocompatibility. AuNPs have physical features that distinguish them from bulk materials, small molecules and other nanoscale particles. Their unique combination of characteristics is just now being fully realized in various biomedical applications. In this review, we focus on the research accomplishments and new opportunities in this field, and we describe the rising developments in the use of monodisperse AuNPs for diagnostic and therapeutic applications. This study addresses the key principles and the most recent published data, focusing on monodisperse AuNP synthesis, surface modifications, and future theranostic applications. Moving forward, we also consider the possible development of functionalized monodisperse AuNPs for theranostic applications based on these efforts. We anticipate that as research advances, flexible AuNPs will become a crucial platform for medical applications.

Current Strategies to Enhance Delivery of Drugs across the Blood–Brain Barrier

The blood–brain barrier (BBB) has shown to be a significant obstacle to brain medication delivery. The BBB in a healthy brain is a diffusion barrier that prevents most substances from passing from the blood to the brain; only tiny molecules can pass across the BBB. The BBB is disturbed in specific pathological illnesses such as stroke, diabetes, seizures, multiple sclerosis, Parkinson’s disease, and Alzheimer’s disease. The goal of this study is to offer a general overview of current brain medication delivery techniques and associated topics from the last five years. It is anticipated that this review will stimulate readers to look into new ways to deliver medications to the brain. Following an introduction of the construction and function of the BBB in both healthy and pathological conditions, this review revisits certain contested questions, such as whether nanoparticles may cross the BBB on their own and if medications are selectively delivered to the brain by deliberately targeted nanoparticles. Current non-nanoparticle options are also discussed, including drug delivery via the permeable BBB under pathological circumstances and the use of non-invasive approaches to improve brain medication absorption.

Crossing the Blood-Brain Barrier: Advances in Nanoparticle Technology for Drug Delivery in Neuro-Oncology

The blood-brain barrier (BBB) constitutes a microvascular network responsible for excluding most drugs from the brain. Treatment of brain tumors is limited by the impermeability of the BBB and, consequently, survival outcomes for malignant brain tumors remain poor. Nanoparticles (NPs) represent a potential solution to improve drug transport to brain tumors, given their small size and capacity to target tumor cells. Here, we review the unique physical and chemical properties of NPs that aid in BBB transport and discuss mechanisms of NP transport across the BBB, including paracellular transport, carrier-mediated transport, and adsorptive- and receptor-mediated transcytosis. The major types of NPs investigated for treatment of brain tumors are detailed, including polymeric NPs, liposomes, solid lipid NPs, dendrimers, metals, quantum dots, and nanogels. In addition to their role in drug delivery, NPs can be used as imaging contrast agents and can be conjugated with imaging probes to assist in visualizing tumors, demarcating lesion boundaries and margins, and monitoring drug delivery and treatment response. Multifunctional NPs can be designed that are capable of targeting tumors for both imaging and therapeutic purposes. Finally, limitations of NPs for brain tumor treatment are discussed.

Potential of Nanocarrier-Based Drug Delivery Systems for Brain Targeting: A Current Review of Literature

The advent of nanotechnologies such as nanocarriers and nanotherapeutics has changed the treatment strategy and developed a more efficacious novel drug delivery system. Various drug delivery systems are focused on drug-targeting of brain cells. However, the manifestation of the brain barrier is the main hurdle for the effective delivery of chemotherapeutics, ultimately causing treatment failure of various drugs. To solve this problem, various nanocarrier-based drug delivery system has been developed for brain targeting. This review outlines nanocarrier-based composites for different brain diseases and highlights nanocarriers for drug targeting towards brain cells. It also summarizes the latest developments in nanocarrier-based delivery systems containing liposomal systems, dendrimers, polymeric micelles, polymeric nanocarriers, quantum dots (QDs), and gold nanoparticles. Besides, the optimal properties of nanocarriers and therapeutic implications for brain targeting have been extensively studied. Finally, the potential applications and research opportunities for nanocarriers in brain targeting are discussed.

Application of Gold Nanoparticle-Based Materials in Cancer Therapy and Diagnostics

Several metal nanoparticles have been developed for medical application. While all have their benefits, gold nanoparticles (AuNPs) are ideal in cancer therapy and diagnosis as they are chemically inert and minimally toxic. Several studies have shown the potential of AuNPs in the therapeutic field, as photosensitizing agents in sonochemical and photothermal therapy and as drug delivery, as well as in diagnostics and theranostics. Although there is a significant number of reviews on the application of AuNPs in cancer medicine, there is no comprehensive review on their application both in therapy and diagnostics. Therefore, considering the high number of studies on AuNPs’ applications, this review summarizes data on the application of AuNPs in cancer therapy and diagnostics. In addition, we looked at the influence of AuNPs’ shape and size on their biological properties. We also present the potential use of hybrid materials based on AuNPs in sonochemical and photothermal therapy and the possibility of their use in diagnostics. Despite their potential, the use of AuNPs and derivatives in cancer medicine still has some limitations. In this review, we provide an overview of the biological, physicochemical, and legal constraints on using AuNPs in cancer medicine.

Distribution of gold nanoparticles into the brain: a systematic review and meta-analysis

Despite the widespread use of gold nanoparticles (GNPs), there is no consensus on their distribution to different tissues and organs. The present systematic review and meta-analysis addresses the accumulation of GNPs in brain tissue. Extensive searches were conducted in electronic databases, Medline, Web of Science, EMBASE, and Scopus. Based on inclusion and exclusion criteria, primary and secondary screening was performed. The value of brain accumulation of gold nanoparticle (the percentage of the injection dose of GNPs/gram of brain tissue that applied as effect size (ES) in analysis) and the standard error of the mean were extracted from articles and analyzed by calculating the pooled ES and the pooled confidence interval (CI) using STATA software. p ≤ 0.05 was considered significant. Thirty-eight studies were included in the meta-analysis. The results showed that the amount of GNPs was 0.06% of the injection dose/gram of brain tissue (ES = 0.06, %95 CI: 0.06-0.06, p < 0.0001). Considering the time between injection and tissue harvest (follow-up time), after 1 h the GNPs in brain tissue was 0.288% of the injection dose/gram of tissue (ES = 0.29, 95% CI: 0.25-0.33, p < 0.0001), while after four weeks it was only 0.02% (ES = 0.02, 95% CI: 0.01-0.03, p < 0.0001) of the injection dose/gram of tissue. The amount of GNPs in brain tissue was higher for PEG-coated GNPs compared to uncoated GNPs, and it was 5.6 times higher for rod-shaped GNPs compared to spherical GNPs. The mean amount of GNPs in the brain tissues of animals bearing a tumor was 5.8 times higher than in normal animals.

Subcellular imaging and diagnosis of cancer using engineered nanoparticles

The advances in the synthesis of nanoparticles with engineered properties are reported to have profound applications in oncological disease detection via optical and multimodal imaging and therapy. Among various nanoparticle-assisted imaging techniques, engineered fluorescent nanoparticles show great promise from high contrast images and localized therapeutic applications. Of all the fluorescent nanoparticles available, the gold nanoparticles, carbon dots, and upconversion nanoparticles are emerging recently as the most promising candidates for diagnosis, treatment, and cancer monitoring. This review addresses the recent progress in engineering the properties of these emerging nanoparticles and their application for cancer diagnosis and therapy. In addition, the potential of these particles for subcellular imaging is also reviewed here.

Current Status of Brain Tumor in the Kingdom of Saudi Arabia and Application of Nanobiotechnology for Its Treatment: A Comprehensive Review

OBJECTIVE

Brain tumors are the most challenging of all tumors and accounts for about 3% of all cancer allied deaths. The aim of the present review is to examine the brain tumor prevalence and treatment modalities available in the Kingdom of Saudi Arabia. It also provides a comprehensive analysis of the application of various nanotechnology-based products for brain cancer treatments along with their prospective future advancements.

METHODS

A literature review was performed to identify and summarize the current status of brain cancer in Saudi Arabia and the scope of nanobiotechnology in its treatment.

RESULTS

Depending upon the study population data analysis, gliomas, astrocytoma, meningioma, and metastatic cancer have a higher incidence rate in Saudi Arabia than in other countries, and are mostly treated in accordance with conventional treatment modalities for brain cancer. Due to the poor prognosis of cancer, it has an average survival rate of 2 years. Conventional therapy includes surgery, radiotherapy, chemotherapy, and a combination thereof, but these do not control the disease's recurrence. Among the various nanomaterials discussed, liposomes and polymeric nanoformulations have demonstrated encouraging outcomes for facilitated brain cancer treatment.

CONCLUSIONS

Nanomaterials possess the capacity to overcome the shortcomings of conventional therapies. Polymer-based nanomaterials have shown encouraging outcomes against brain cancer when amalgamated with other nano-based therapies. Nonetheless, nanomaterials could be devised that possess minimal toxicity towards normal cells or that specifically target tumor cells. In addition, rigorous clinical investigations are warranted to prepare them as an efficient and safe modality for brain cancer therapy.

Targeted brain tumor imaging by using discrete biopolymer-coated nanodiamonds across the blood-brain barrier

Short circulation lifetime, poor blood-brain barrier (BBB) permeability and low targeting specificity limit nanovehicles from crossing the vascular barrier and reaching the tumor site. Consequently, the precise diagnosis of malignant brain tumors remains a great challenge. This study demonstrates the imaging of photostable biopolymer-coated nanodiamonds (NDs) with tumor targeting properties inside the brain. NDs are labeled with PEGylated denatured bovine serum albumin (BSA) and tumor vasculature targeting tripeptides RGD. The modified NDs show high colloidal stability in different buffer systems. Moreover, it is found that discrete dcBSA-PEG-NDs cross the in vitro BBB model more effectively than aggregated NDs. Importantly, compared with the non-targeting NDs, RGD-dcBSA-PEG-NDs can selectively target the tumor site in U-87 MG bearing mice after systemic injection. Overall, this discrete ND system enables efficacious brain tumor visualization with minimal toxicity to other major organs, and is worthy of further investigation into the applications as a unique platform for noninvasive theragnostics and/or thermometry at different stages of human diseases in the brain.

Tumor type detection in brain MR images of the deep model developed using hypercolumn technique, attention modules, and residual blocks

Brain cancer is a disease caused by the growth of abnormal aggressive cells in the brain outside of normal cells. Symptoms and diagnosis of brain cancer cases are producing more accurate results day by day in parallel with the development of technological opportunities. In this study, a deep learning model called BrainMRNet which is developed for mass detection in open-source brain magnetic resonance images was used. The BrainMRNet model includes three processing steps: attention modules, the hypercolumn technique, and residual blocks. To demonstrate the accuracy of the proposed model, three types of tumor data leading to brain cancer were examined in this study: glioma, meningioma, and pituitary. In addition, a segmentation method was proposed, which additionally determines in which lobe area of the brain the two classes of tumors that cause brain cancer are more concentrated. The classification accuracy rates were performed in the study; it was 98.18% in glioma tumor, 96.73% in meningioma tumor, and 98.18% in pituitary tumor. At the end of the experiment, using the subset of glioma and meningioma tumor images, it was determined which at brain lobe the tumor region was seen, and 100% success was achieved in the analysis of this determination. In this study, a hybrid deep learning model is presented to determine the detection of the brain tumor. In addition, open-source software was proposed, which statistically found in which lobe region of the human brain the brain tumor occurred. The methods applied and tested in the experiments have shown promising results with a high level of accuracy, precision, and specificity. These results demonstrate the availability of the proposed approach in clinical settings to support the medical decision regarding brain tumor detection.

Tumor type detection in brain MR images of the deep model developed using hypercolumn technique, attention modules, and residual blocks

Brain cancer is a disease caused by the growth of abnormal aggressive cells in the brain outside of normal cells. Symptoms and diagnosis of brain cancer cases are producing more accurate results day by day in parallel with the development of technological opportunities. In this study, a deep learning model called BrainMRNet which is developed for mass detection in open-source brain magnetic resonance images was used. The BrainMRNet model includes three processing steps: attention modules, the hypercolumn technique, and residual blocks. To demonstrate the accuracy of the proposed model, three types of tumor data leading to brain cancer were examined in this study: glioma, meningioma, and pituitary. In addition, a segmentation method was proposed, which additionally determines in which lobe area of the brain the two classes of tumors that cause brain cancer are more concentrated. The classification accuracy rates were performed in the study; it was 98.18% in glioma tumor, 96.73% in meningioma tumor, and 98.18% in pituitary tumor. At the end of the experiment, using the subset of glioma and meningioma tumor images, it was determined which at brain lobe the tumor region was seen, and 100% success was achieved in the analysis of this determination. In this study, a hybrid deep learning model is presented to determine the detection of the brain tumor. In addition, open-source software was proposed, which statistically found in which lobe region of the human brain the brain tumor occurred. The methods applied and tested in the experiments have shown promising results with a high level of accuracy, precision, and specificity. These results demonstrate the availability of the proposed approach in clinical settings to support the medical decision regarding brain tumor detection.

Nanomaterials for Diagnosis and Treatment of Brain Cancer: Recent Updates

Brain tumors, especially glioblastoma, remain the most aggressive form of all the cancers because of inefficient diagnosis and profiling. Nanostructures, such as metallic nanostructures, silica nano-vehicles, quantum dots, lipid nanoparticles (NPs) and polymeric NPs, with high specificity have made it possible to permeate the blood–brain barrier (BBB). NPs possess optical, magnetic and photodynamic properties that can be exploited by surface modification, bio composition, contrast agents’ encapsulation and coating by tumor-derived cells. Hence, nanotechnology has brought on a revolution in the field of diagnosis and imaging of brain tumors and cancers. Recently, nanomaterials with biomimetic functions have been introduced to efficiently cross the BBB to be engulfed by deep skin tumors and cancer malignancies for imaging. The review focuses on nanotechnology-based diagnostic and imaging approaches for exploration in brain tumors and cancers. Moreover, the review also summarizes a few strategies to image glioblastoma and cancers by multimodal functional nanocomposites for more precise and accurate clinical diagnosis. Their unique physicochemical attributes, including nanoscale sizes, larger surface area, explicit structural features and ability to encapsulate diverse molecules on their surface, render nanostructured materials as excellent nano-vehicles to cross the blood–brain barrier and convey drug molecules to their target region. This review sheds light on the current progress of various kinds of nanomaterials, such as liposomes, nano-micelles, dendrimers, carbon nanotubes, carbon dots and NPs (gold, silver and zinc oxide NPs), for efficient drug delivery in the treatment and diagnosis of brain cancer.

In vitro Label Free Raman Microspectroscopic Analysis to Monitor the Uptake, Fate and Impacts of Nanoparticle Based Materials

The continued emergence of nanoscale materials for nanoparticle-based therapy, sensing and imaging, as well as their more general adoption in a broad range of industrial applications, has placed increasing demands on the ability to assess their interactions and impacts at a cellular and subcellular level, both in terms of potentially beneficial and detrimental effects. Notably, however, many such materials have been shown to interfere with conventional in vitro cellular assays that record only a single colorimetric end-point, challenging the ability to rapidly screen cytological responses. As an alternative, Raman microspectroscopy can spatially profile the biochemical content of cells, and any changes to it as a result of exogenous agents, such as toxicants or therapeutic agents, in a label free manner. In the confocal mode, analysis can be performed at a subcellular level. The technique has been employed to confirm the cellular uptake and subcellular localization of polystyrene nanoparticles (PSNPs), graphene and molybdenum disulfide micro/nano plates (MoS₂), based on their respective characteristic spectroscopic signatures. In the case of PSNPs it was further employed to identify their local subcellular environment in endosomes, lysosomes and endoplasmic reticulum, while for MoS₂ particles, it was employed to monitor subcellular degradation as a function of time. For amine functionalized PSNPs, the potential of Raman microspectroscopy to quantitatively characterize the dose and time dependent toxic responses has been explored, in a number of cell lines. Comparing the responses to those of poly (amidoamine) nanoscale polymeric dendrimers, differentiation of apoptotic and necrotic pathways based on the cellular spectroscopic responses was demonstrated. Drawing in particular from the experience of the authors, this paper details the progress to date in the development of applications of Raman microspectroscopy for in vitro, label free analysis of the uptake, fate and impacts of nanoparticle based materials, in vitro, and the prospects for the development of a routine, label free high content spectroscopic analysis technique.

Role of gold nanoparticles in advanced biomedical applications

Gold nanoparticles (GNPs) have generated keen interest among researchers in recent years due to their excellent physicochemical properties. In general, GNPs are biocompatible, amenable to desired functionalization, non-corroding, and exhibit size and shape dependent optical and electronic properties. These excellent properties of GNPs exhibit their tremendous potential for use in diverse biomedical applications. Herein, we have evaluated the recent advancements of GNPs to highlight their exceptional potential in the biomedical field. Special focus has been given to emerging biomedical applications including bio-imaging, site specific drug/gene delivery, nano-sensing, diagnostics, photon induced therapeutics, and theranostics. We have also elaborated on the basics, presented a historical preview, and discussed the synthesis strategies, functionalization methods, stabilization techniques, and key properties of GNPs. Lastly, we have concluded this article with key findings and unaddressed challenges. Overall, this review is a complete package to understand the importance and achievements of GNPs in the biomedical field.

Electroconductive Nanobiomaterials for Tissue Engineering and Regenerative Medicine

Regenerative medicine aims to engineer tissue constructs that can recapitulate the functional and structural properties of native organs. Most novel regenerative therapies are based on the recreation of a three-dimensional environment that can provide essential guidance for cell organization, survival, and function, which leads to adequate tissue growth. The primary motivation in the use of conductive nanomaterials in tissue engineering has been to develop biomimetic scaffolds to recapitulate the electrical properties of the natural extracellular matrix, something often overlooked in numerous tissue engineering materials to date. In this review article, we focus on the use of electroconductive nanobiomaterials for different biomedical applications, particularly, very recent advancements for cardiovascular, neural, bone, and muscle tissue regeneration. Moreover, this review highlights how electroconductive nanobiomaterials can facilitate cell to cell crosstalk (i.e., for cell growth, migration, proliferation, and differentiation) in different tissues. Thoughts on what the field needs for future growth are also provided.

Nanocrystallized Oleanolic Acid Better Inhibits Proliferation, Migration and Invasion in Intracranial Glioma via Caspase-3 Pathway

Glioma associates with high malignancy and poor prognosis for traditional treatment. Oleanolic acid (OA) has been confirmed to have an inhibitory effect on different kinds of tumors, while accompanying with low efficiency because of its large molecular mass and low solubility. Nanoliposome is an appropriate drug delivery system that can compensate for the limitations of traditional insoluble drugs, involving improvement of their solubility, stability and lipophilicity. In the present study, we comprised of OA covered with nanoliposomes, named OA^nano, to observe antitumor effects on U87 glioma cells. The results showed that OA^nano raised the solubility and oil-water partition coefficient. OA^nano suppressed proliferation of U87 glioma cells, and also had an anticancer effect on U87 glioma cells, which was found to be higher than that of OA. Moreover, treatment with OA^nano induced apoptosis and degraded migration ability by caspase-3 pathway. In conclusion, our results demonstrated that OA covered with nanoliposomes led to enhanced anticancer effects by suppressing proliferation, migration and invasion abilities. The findings may provide a reliable reference for development of new anti-cancer drugs.

Gold Nanoparticles in Glioma Theranostics

Despite many endeavors to treat malignant gliomas in the last decades, the median survival of patients has not significantly improved. The infiltrative nature of high-grade gliomas and the impermeability of the blood-brain barrier to the most therapeutic agents remain major hurdles, impeding an efficacious treatment. Theranostic platforms bridging diagnosis and therapeutic modalities aim to surmount the current limitations in diagnosis and therapy of glioma. Gold nanoparticles (AuNPs) due to their biocompatibility and tunable optical properties have widely been utilized for an assortment of theranostic purposes. In this Review, applications of AuNPs as imaging probes, drug/gene delivery systems, radiosensitizers, photothermal transducers, and multimodal theranostic agents in malignant gliomas are discussed. This Review also aims to provide a perspective on cancer theranostic applications of AuNPs in future clinical trials.

Glioblastoma multiforme: a glance at advanced therapies based on nanotechnology

Glioblastoma multiforme (GBM, grade IV) is the most common malignant and invasive central nervous system tumor with poor survival outcome. Various pathogenesis signatures such as genetic mutation, hypoxia, necrosis and neo-angiogenesis are involved in GBM. Standard treatment includes surgical resection along with radiation therapy and temozolomide (TMZ) chemotherapy that do not improve the overall survival of patients. In this review, we focused on the diagnosis, risk factors and novel therapies, using advanced therapies such as nanotechnology in drug delivery, gene therapy and hyperthermia that have promising roles in the treatment of aggressive brain tumors.

Gold Nanoparticles in Conjunction with Nucleic Acids as a Modern Molecular System for Cellular Delivery

Development of nanotechnology has become prominent in many fields, such as medicine, electronics, production of materials, and modern drugs. Nanomaterials and nanoparticles have gained recognition owing to the unique biochemical and physical properties. Considering cellular application, it is speculated that nanoparticles can transfer through cell membranes following different routes exclusively owing to their size (up to 100 nm) and surface functionalities. Nanoparticles have capacity to enter cells by themselves but also to carry other molecules through the lipid bilayer. This quality has been utilized in cellular delivery of substances like small chemical drugs or nucleic acids. Different nanoparticles including lipids, silica, and metal nanoparticles have been exploited in conjugation with nucleic acids. However, the noble metal nanoparticles create an alternative, out of which gold nanoparticles (AuNP) are the most common. The hybrids of DNA or RNA and metal nanoparticles can be employed for functional assemblies for variety of applications in medicine, diagnostics or nano-electronics by means of biomarkers, specific imaging probes, or gene expression regulatory function. In this review, we focus on the conjugates of gold nanoparticles and nucleic acids in the view of their potential application for cellular delivery and biomedicine. This review covers the current advances in the nanotechnology of DNA and RNA-AuNP conjugates and their potential applications. We emphasize the crucial role of metal nanoparticles in the nanotechnology of nucleic acids and explore the role of such conjugates in the biological systems. Finally, mechanisms guiding the process of cellular intake, essential for delivery of modern therapeutics, will be discussed.

Integration of gadolinium in nanostructure for contrast enhanced-magnetic resonance imaging

Magnetic resonance imaging (MRI) is a routinely used imaging technique in medical diagnostics, which is further enhanced with the use of contrast agents (CAs). The most commonly used CAs are gadolinium-based contrast agents (GBCAs), in which gadolinium (Gd) is chelated with organic chelating agents (linear or cyclic). However, the use of GBCA is related to toxic side effect due to the release of free Gd³⁺ ions from the chelating agents. The repeated use of GBCAs has led to Gd deposition in various major organs including bone, brain, and kidneys. As a result, the use of GBCA has been linked to the development of nephrogenic systemic fibrosis (NSF). Due to the GBCA associated toxicities, some clinically approved GBCAs have been limited or revoked recently. Therefore, there is an urgent need for the development of new strategies to chelate and stabilize Gd³⁺ ions for contrast enhancement, safety profile, and selective imaging of a pathological site. Toward this endeavor, GBCAs have been engineered using different nanoparticulate systems to improve their stability, biocompatibility, and pharmacokinetics. Throughout this review, some of the important strategies for engineering small molecular Gd³⁺ chelates into a nanoconstruct is discussed. We focus on the development of GBCAs as liposomes, mesoporous silica nanoparticles (MSNs), polymeric nanocarriers, and plasmonic nanoparticles-based design strategies to improve safety and contrast enhancement for contrast enhanced-magnetic resonance imaging (Ce-MRI). We also discuss the in-vitro/in-vivo properties of strategically designed nanoscale MRI CAs, its potentials, and limitations. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Diagnostic Tools > Diagnostic Nanodevices Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials.

Nanostructure Endows Neurotherapeutic Potential in Optogenetics: Current Development and Future Prospects

Optogenetics have evolved as a promising tool to control the processes at a cellular level via photons. Specially, it confers a specific control over cellular function through real-time cytomodulation even in freely moving animals. Neuronal stimulation is prerequisite for deep tissue light penetration or insertion of optrode for light illumination to the neurons that have been proven to be compromised due to poor light penetration and invasiveness of the procedure, respectively. In this review, the application of nanotechnology is being elaborated by the use of metal nanoparticles (AuNPs), upconversion nanocrystals (UCNPs), and quantum dots (CdSe) for targeting particular organs or tissues, and their potential to emit a specific light on excitation to overcome the limitations associated with earlier methods has been elucidated. The optothermal and magnetothermal properties, photoluminescence, and higher photostability of nanomaterials are explored in context of therapeutic applicability of optogenetics. The nanostructure characteristics and specific ion channel targeting have shown promising therapeutic potential against neurodegenerative disorders (Alzheimer's, Parkinson's, Huntington's), epilepsy, and blindness. This review compiles mechanical and optical characteristics of nanomaterials that endow superior optogenetic therapeutic potentials to cure immedicable infirmities.

Biochemical Changes in Human Cells Exposed to Low Concentrations of Gold Nanoparticles Detected by Raman Microspectroscopy

The toxicological implications of nanoparticles deserve accurate scientific investigation for the protection of human health. Although toxic effects involve specific organs, the events that cause them have their origin from biochemical modifications of some cellular constituents. Therefore, a first analysis to evaluate the effects due to the action of nanoparticles is achieved by investigation of in vitro cells, which allows the identification of the cellular modifications caused by nanoparticles (NPs) even at much lower doses than the lethal ones. This work evaluated the Raman microspectroscopy capability to monitor biochemical changes occurring in human cells as a consequence of exposure to a suspension of gold nanoparticles with a non-cytotoxic concentration. Human keratinocyte cells were used as a model cell line, because they are mainly involved in environmental exposure. A trypan blue assay revealed that the investigated concentration, 650 ng/mL, is non-cytotoxic (about 5% of cells died after 48 h exposure). Specific Raman spectral markers to represent the cell response to nanoparticle exposure were found (at 1450 and 2865 cm^-1) in the cytoplasm spectra, with the aid of ratiometric and principal component analysis.

Contrast Agents Delivery: An Up-to-Date Review of Nanodiagnostics in Neuroimaging

Neuroimaging is a highly important field of neuroscience, with direct implications for the early diagnosis and progression monitoring of brain-associated diseases. Neuroimaging techniques are categorized into structural, functional and molecular neuroimaging, each possessing advantages and disadvantages in terms of resolution, invasiveness, toxicity of contrast agents and costs. Nanotechnology-based approaches for neuroimaging mostly involve the development of nanocarriers for incorporating contrast agents or the use of nanomaterials as imaging agents. Inorganic and organic nanoparticles, liposomes, micelles, nanobodies and quantum dots are some of the most studied candidates for the delivery of contrast agents for neuroimaging. This paper focuses on describing the conventional modalities used for imaging and the applications of nanotechnology for developing novel strategies for neuroimaging. The aim is to highlight the roles of nanocarriers for enhancing and/or overcome the limitations associated with the most commonly utilized neuroimaging modalities. For future directions, several techniques that could benefit from the increased contrast induced by using imaging probes are presented.

Nanoplasmonics in Paper-Based Analytical Devices

Chemical and biological sensing are crucial tools in science and technology. Plasmonic nanoparticles offer a virtually limitless number of photons for sensing applications, which can be available for visual detection over long periods. Moreover, cellulosic materials, such as paper, represent a versatile building block for implementation of simple, yet valuable, microfluidic analytical devices. This mini review outlines the basic theory of nanoplasmonics and the usability of paper as a nanoplasmonic substrate exploiting its features as a (bio)sensing platform based on different mechanisms depending on localized surface plasmon resonance response. Progress, current trends, challenges and opportunities are also underscored. It is intended for general researchers and technologists who are new to the topic as well as specialist/experts in the field.

Emerging blood–brain-barrier-crossing nanotechnology for brain cancer theranostics

The advancements, perspectives, and challenges in blood–brain-barrier (BBB)-crossing nanotechnology for effective brain tumor delivery and highly efficient brain cancer theranostics.

Inhaled nanomaterials and the respiratory microbiome: clinical, immunological and toxicological perspectives

Our development and usage of engineered nanomaterials has grown exponentially despite concerns about their unfavourable cardiorespiratory consequence, one that parallels ambient ultrafine particle exposure from vehicle emissions. Most research in the field has so far focused on airway inflammation in response to nanoparticle inhalation, however, little is known about nanoparticle-microbiome interaction in the human airway and the environment. Emerging evidence illustrates that the airway, even in its healthy state, is not sterile. The resident human airway microbiome is further altered in chronic inflammatory respiratory disease however little is known about the impact of nanoparticle inhalation on this airway microbiome. The composition of the airway microbiome, which is involved in the development and progression of respiratory disease is dynamic, adding further complexity to understanding microbiota-host interaction in the lung, particularly in the context of nanoparticle exposure. This article reviews the size-dependent properties of nanomaterials, their body deposition after inhalation and factors that influence their fate. We evaluate what is currently known about nanoparticle-microbiome interactions in the human airway and summarise the known clinical, immunological and toxicological consequences of this relationship. While associations between inhaled ambient ultrafine particles and host immune-inflammatory response are known, the airway and environmental microbiomes likely act as intermediaries and facilitate individual susceptibility to inhaled nanoparticles and toxicants. Characterising the precise interaction between the environment and airway microbiomes, inhaled nanoparticles and the host immune system is therefore critical and will provide insight into mechanisms promoting nanoparticle induced airway damage.