The road ahead to successful BBB opening and drug-delivery with focused ultrasound

This review delves into the innovative technology of Blood-Brain Barrier (BBB) opening with low-intensity focused ultrasound in combination with microbubbles (LIFU-MB), a promising therapeutic modality aimed at enhancing drug delivery to the central nervous system (CNS). The BBB's selective permeability, while crucial for neuroprotection, significantly hampers the efficacy of pharmacological treatments for CNS disorders. LIFU-MB emerges as a non-invasive and localized method to transiently increase BBB permeability, facilitating the delivery of therapeutic molecules. Here, we review the procedural stages of LIFU-MB interventions, including planning and preparation, sonication, evaluation, and delivery, highlighting the technological diversity and methodological challenges encountered in current clinical applications. With an emphasis on safety and efficacy, we discuss the crucial aspects of ultrasound delivery, microbubble administration, acoustic feedback monitoring and assessment of BBB permeability. Finally, we explore the critical choices for effective BBB opening with LIFU-MB, focusing on selecting therapeutic agents, optimizing delivery methods, and timing for delivery. Overcoming existing barriers to integrate this technology into clinical practice could potentially revolutionize CNS drug delivery and treatment paradigms in the near future.

Modifications of Nanobubble Therapy for Cancer Treatment

Cancer development is related to genetic mutations in primary cells, where 5-10% of all cancers are derived from acquired genetic defects, most of which are a consequence of the environment and lifestyle. As it turns out, over half of cancer deaths are due to the generation of drug resistance. The local delivery of chemotherapeutic drugs may reduce their toxicity by increasing their therapeutic dose at targeted sites and by decreasing the plasma levels of circulating drugs. Nanobubbles have attracted much attention as an effective drug distribution system due to their non-invasiveness and targetability. This review aims to present the characteristics of nanobubble systems and their efficacy within the biomedical field with special emphasis on cancer treatment. In vivo and in vitro studies on cancer confirm nanobubbles' ability and good blood capillary perfusion; however, there is a need to define their safety and side effects in clinical trials.

Targeting Nrf2 signaling pathways in the role of bladder cancer: From signal network to targeted therapy

Bladder cancer (BC) is the most common malignancy of the urinary system and often recurs after tumor removal and/or is resistant to chemotherapy. In cancer cells, the activity of the signaling pathway changes significantly, affecting a wide range of cell activities from growth and proliferation to apoptosis, invasion and metastasis. Nrf2 is a transcription factor that plays an important role in cellular defense responses to a variety of cellular stresses. There is increasing evidence that Nrf2 acts as a tumor driver and that it is involved in the maintenance of malignant cell phenotypes. Abnormal expression of Nrf2 has been found to be common in a variety of tumors, including bladder cancer. Over-activation of Nrf2 can lead to DNA damage and the development of bladder cancer, and is also associated with various pathological phenomena of bladder cancer, such as metastasis, angiogenesis, and reduced toxicity and efficacy of therapeutic anticancer drugs to provide cell protection for cancer cells. However, the above process can be effectively inhibited or reversed by inhibiting Nrf2. Therefore, Nrf2 signaling may be a potential targeting pathway for bladder cancer. In this review, we will characterize this signaling pathway and summarize the effects of Nrf2 and crosstalk with other signaling pathways on bladder cancer progression. The focus will be on the impact of Nrf2 activation on bladder cancer progression and current therapeutic strategies aimed at blocking the effects of Nrf2. To better determine how to promote new chemotherapy agents, develop new therapeutic agents, and potential therapeutic targets.

A Systematic Study on Long-acting Nanobubbles: Current Advancement and Prospects on Theranostic Properties

Delivery of diagnostic drugs via nanobubbles (NBs) has shown to be an emerging field of study. Due to their small size, NBs may more easily travel through constricted blood vessels and precisely target certain bodily parts. NB is considered the major treatment for cancer treatment and other diseases which are difficult to diagnose. The field of NBs is dynamic and continues to grow as researchers discover new properties and seek practical applications in various fields. The predominant usage of NBs in novel drug delivery is to enhance the bioavailability, and controlled drug release along with imaging properties NBs are important because they may change interfacial characteristics including surface force, lubrication, and absorption. The quick diffusion of gas into the water was caused by a hypothetical film that was stimulated and punctured by a strong acting force at the gas/water contact of the bubble. In this article, various prominent aspects of NBs have been discussed, along with the long-acting nature, and the theranostical aspect which elucidates the potential marketed drugs along with clinical trial products. The article also covers quality by design aspects, different production techniques that enable method-specific therapeutic applications, increasing the floating time of the bubble, and refining its properties to enhance the prepared NB's quality. NB containing both analysis and curing properties makes it special from other nano-carriers. This work includes all the possible methods of preparing NB, its application, all marketed drugs, and products in clinical trials.

A novel vaccination strategy against Vibrio harveyi infection in Asian seabass (Lates calcarifer) with the aid of oxygen nanobubbles and chitosan

Immersion vaccination, albeit easier to administer than immunization by injection, sometimes has challenges with antigen uptake, resulting in sub-optimal protection. In this research, a new strategy to enhance antigen uptake of a heat-inactivated Vibrio harveyi vaccine in Asian seabass (Lates calcarifer) using oxygen nanobubble-enriched water (ONB) and positively charged chitosan (CS) was explored. Antigen uptake in fish gills was assessed, as was the antibody response and vaccine efficacy of four different combinations of vaccine with ONB and CS, and two control groups. Pre-mixing of ONB and CS before introducing the vaccine, referred to as (ONB + CS) + Vac, resulted in superior antigen uptake and anti-V. harveyi antibody (IgM) production in both serum and mucus compared to other formulas. The integration of an oral booster (4.22 × 108 CFU/g, at day 21-25) within a vaccine trial experiment set out to further evaluate how survival rates post exposure to V. harveyi might be improved. Antibody responses were measured over 42 days, and vaccine efficacy was assessed through an experimental challenge with V. harveyi. The expression of immune-related genes IL1β, TNFα, CD4, CD8, IgT and antibody levels were assessed at 1, 3, and 7-day(s) post challenge (dpc). The results revealed that antibody levels in the group (ONB + CS) + Vac were consistently higher than the other groups post immersion immunization and oral booster, along with elevated expression of immune-related genes after challenge with V. harveyi. Ultimately, this group demonstrated a significantly higher relative percent survival (RPS) of 63 % ± 10.5 %, showcasing the potential of the ONB-CS-Vac complex as a promising immersion vaccination strategy for enhancing antigen uptake, stimulating immunological responses, and improving survival of Asian seabass against vibriosis.

Increased Absorption of Thyroxine in a Murine Model of Hypothyroidism Using Water/CO2 Nanobubbles

Thyroxine (T4) is a drug extensively utilized for the treatment of hypothyroidism. However, the oral absorption of T4 presents certain limitations. This research investigates the efficacy of CO2 nanobubbles in water as a potential oral carrier for T4 administration to C57BL/6 hypothyroid mice. Following 18 h of fasting, the formulation was administered to the mice, demonstrating that the combination of CO2 nanobubbles and T4 enhanced the drug's absorption in blood serum by approximately 40%. To comprehend this observation at a molecular level, we explored the interaction mechanism through which T4 engages with the CO2 nanobubbles, employing molecular simulations, semi-empirical quantum mechanics, and PMF calculations. Our simulations revealed a high affinity of T4 for the water-gas interface, driven by additive interactions between the hydrophobic region of T4 and the gas phase and electrostatic interactions of the polar groups of T4 with water at the water-gas interface. Concurrently, we observed that at the water-gas interface, the cluster of T4 formed in the water region disassembles, contributing to the drug's bioavailability. Furthermore, we examined how the gas within the nanobubbles aids in facilitating the drug's translocation through cell membranes. This research contributes to a deeper understanding of the role of CO2 nanobubbles in drug absorption and subsequent release into the bloodstream. The findings suggest that utilizing CO2 nanobubbles could enhance T4 bioavailability and cell permeability, leading to more efficient transport into cells. Additional research opens the possibility of employing lower concentrations of this class of drugs, thereby potentially reducing the associated side effects due to poor absorption.

Ultrasound-Sensitive Intelligent Nanosystems: A Promising Strategy for the Treatment of Neurological Diseases

Neurological diseases are a major global health challenge, affecting hundreds of millions of people worldwide. Ultrasound therapy plays an irreplaceable role in the treatment of neurological diseases due to its noninvasive, highly focused, and strong tissue penetration capabilities. However, the complexity of brain and nervous system and the safety risks associated with prolonged exposure to ultrasound therapy severely limit the applicability of ultrasound therapy. Ultrasound-sensitive intelligent nanosystems (USINs) are a novel therapeutic strategy for neurological diseases that bring greater spatiotemporal controllability and improve safety to overcome these challenges. This review provides a detailed overview of therapeutic strategies and clinical advances of ultrasound in neurological diseases, focusing on the potential of USINs-based ultrasound in the treatment of neurological diseases. Based on the physical and chemical effects induced by ultrasound, rational design of USINs is a prerequisite for improving the efficacy of ultrasound therapy. Recent developments of ultrasound-sensitive nanocarriers and nanoagents are systemically reviewed. Finally, the challenges and developing prospects of USINs are discussed in depth, with a view to providing useful insights and guidance for efficient ultrasound treatment of neurological diseases.

The contemplation of amylose for the delivery of ulcerogenic nonsteroidal anti-inflammatory drugs

This manuscript proposes an innovative approach to mitigate the gastrointestinal adversities linked with nonsteroidal anti-inflammatory drugs (NSAIDs) by exploiting amylose as a novel drug delivery carrier. The intrinsic attributes of V-amylose, such as its structural uniqueness, biocompatibility and biodegradability, as well as its capacity to form inclusion complexes with diverse drug molecules, are meticulously explored. Through a comprehensive physicochemical analysis of V-amylose and ulcerogenic NSAIDs, the plausibility of amylose as a protective carrier for ulcerogenic NSAIDs to gastrointestinal regions is elucidated. This review further discusses the potential therapeutic advantages of amylose-based drug delivery systems in the management of gastric ulcers. By providing controlled release kinetics and enhanced bioavailability, these systems offer promising prospects for the development of more effective ulcer therapies.

Efficient ultrasound-mediated drug delivery to orthotopic liver tumors - Direct comparison of doxorubicin-loaded nanobubbles and microbubbles

Liver metastasis is a major obstacle in treating aggressive cancers, and current therapeutic options often prove insufficient. To overcome these challenges, there has been growing interest in ultrasound-mediated drug delivery using lipid-shelled microbubbles (MBs) and nanobubbles (NBs) as promising strategies for enhancing drug delivery to tumors. Our previous work demonstrated the potential of Doxorubicin-loaded C3F8 NBs (hDox-NB, 280 ± 123 nm) in improving cancer treatment in vitro using low-frequency unfocused therapeutic ultrasound (TUS). In this study, we investigated the pharmacokinetics and biodistribution of sonicated hDox-NBs in orthotopic rat liver tumors. We compared their delivery and therapeutic efficiency with size-isolated MBs (hDox-MB, 1104 ± 373 nm) made from identical shell material and core gas. Results showed a similar accumulation of hDox in tumors treated with hDox-MBs and unfocused therapeutic ultrasound (hDox-MB + TUS) and hDox-NB + TUS. However, significantly increased apoptotic cell death in the tumor and fewer off-target apoptotic cells in the normal liver were found upon the treatment with hDox-NB + TUS. The tumor-to-liver apoptotic ratio was elevated 9.4-fold following treatment with hDox-NB + TUS compared to hDox-MB + TUS, suggesting that the therapeutic efficacy and specificity are significantly increased when using hDox-NB + TUS. These findings highlight the potential of this approach as a viable treatment modality for liver tumors. By elucidating the behavior of drug-loaded bubbles in vivo, we aim to contribute to developing more effective liver cancer treatments that could ultimately improve patient outcomes and decrease off-target side effects.

Exploring the Theranostic Applications and Prospects of Nanobubbles

Anticancer medications as well as additional therapeutic compounds, have poor clinical effectiveness due to their diverse distribution, non-selectivity for malignant cells, and undesirable off-target side effects. As a result, ultrasound-based targeted delivery of therapeutic compounds carried in sophisticated nanocarriers has grown in favor of cancer therapy and control. Nanobubbles are nanoscale bubbles that exhibit unique physiochemical properties in both their inner core and outer shell. Manufacturing nanobubbles primarily aims to enhance therapeutic agents' bioavailability, stability, and targeted delivery. The small size of nanobubbles allows for their extravasation from blood vessels into surrounding tissues and site-specific release through ultrasound targeting. Ultrasound technology is widely utilized for therapy due to its speed, safety, and cost-effectiveness, and micro/nanobubbles, as ultrasound contrast agents, have numerous potential applications in disease treatment. Thus, combining ultrasound applications with NBs has recently demonstrated increased localization of anticancer molecules in tumor tissues with triggered release behavior. Consequently, an effective therapeutic concentration of drugs/genes is achieved in target tumor tissues with ultimately increased therapeutic efficacy and minimal side effects on other non-cancerous tissues. This paper provides a brief overview of the production processes for nanobubbles, along with their key characteristics and potential therapeutic uses.

Nanobubble-mediated cancer cell sonoporation using low-frequency ultrasound

Ultrasound insonation of microbubbles can form transient pores in cell membranes that enable the delivery of non-permeable extracellular molecules to the cells. Reducing the size of microbubble contrast agents to the nanometer range could facilitate cancer sonoporation. This size reduction can enhance the extravasation of nanobubbles into tumors after an intravenous injection, thus providing a noninvasive sonoporation platform. However, drug delivery efficacy depends on the oscillations of the bubbles, the ultrasound parameters and the size of the target compared to the membrane pores. The formation of large pores is advantageous for the delivery of large molecules, however the small size of the nanobubbles limit the bioeffects when operating near the nanobubble resonance frequency at the MHz range. Here, we show that by coupling nanobubbles with 250 kHz low frequency ultrasound, high amplitude oscillations can be achieved, which facilitate low energy sonoporation of cancer cells. This is beneficial both for increasing the uptake of a specific molecule and to improve large molecule delivery. The method was optimized for the delivery of four fluorescent molecules ranging in size from 1.2 to 70 kDa to breast cancer cells, while comparing the results to targeted microbubbles. Depending on the fluorescent molecule size, the optimal ultrasound peak negative pressure was found to range between 300 and 500 kPa. Increasing the pressure to 800 kPa reduced the fraction of fluorescent cells for all molecules sizes. The optimal uptake for the smaller molecule size of 4 kDa resulted in a fraction of 19.9 ± 1.8% of fluorescent cells, whereas delivery of 20 kDa and 70 kDa molecules yielded 14 ± 0.8% and 4.1 ± 1.1%, respectively. These values were similar to targeted microbubble-mediated sonoporation, suggesting that nanobubbles can serve as noninvasive sonoporation agents with a similar potency, and at a reduced bubble size. The nanobubbles effectively reduced cell viability and may thus potentially reduce the tumor burden, which is crucial for the success of cancer treatment. This method provides a non-invasive and low-energy tumor sonoporation theranostic platform, which can be combined with other therapies to maximize the therapeutic benefits of cancer treatment or be harnessed in gene therapy applications.

Encapsulation in Oxygen-Loaded Nanobubbles Enhances the Antimicrobial Effectiveness of Photoactivated Curcumin

In both healthcare and agriculture, antibiotic resistance is an alarming issue. Biocompatible and biodegradable ingredients (e.g., curcumin) are given priority in "green" criteria supported by the Next Generation EU platform. The solubility and stability of curcumin would be significantly improved if it were enclosed in nanobubbles (NB), and photoactivation with the correct wavelength of light can increase its antibacterial efficacy. A continuous release of curcumin over a prolonged period was provided by using innovative chitosan-shelled carriers, i.e., curcumin-containing nanobubbles (Curc-CS-NBs) and oxygen-loaded curcumin-containing nanobubbles (Curc-Oxy-CS-NBs). The results demonstrated that after photoactivation, both types of NBs exhibited increased effectiveness. For Staphylococcus aureus, the minimum inhibitory concentration (MIC) for Curc-CS-NBs remained at 46 µg/mL following photodynamic activation, whereas it drastically dropped to 12 µg/mL for Curc-Oxy-CS-NBs. Enterococcus faecalis shows a decreased MIC for Curc-CS-NB and Curc-Oxy-CS-NB (23 and 46 µg/mL, respectively). All bacterial strains were more effectively killed by NBs that had both oxygen and LED irradiation. A combination of Curc-Oxy-CS-NB and photodynamic stimulation led to a killing of microorganisms due to ROS-induced bacterial membrane leakage. This approach was particularly effective against Escherichia coli. In conclusion, this work shows that Curc-CS-NBs and Curc-Oxy-CS-exhibit extremely powerful antibacterial properties and represent a potential strategy to prevent antibiotic resistance and encourage the use of eco-friendly substitutes in agriculture and healthcare.

Enhanced Anti-Herpetic Activity of Valacyclovir Loaded in Sulfobutyl-ether-β-cyclodextrin-decorated Chitosan Nanodroplets

Valacyclovir (VACV) was developed as a prodrug of the most common anti-herpetic drug Acyclovir (ACV), aiming to enhance its bioavailability. Nevertheless, prolonged VACV oral treatment may lead to the development of important side effects. Nanotechnology-based formulations for vaginal administration represent a promising approach to increase the concentration of the drug at the site of infection, limiting systemic drug exposure and reducing systemic toxicity. In this study, VACV-loaded nanodroplet (ND) formulations, optimized for vaginal delivery, were designed. Cell-based assays were then carried out to evaluate the antiviral activity of VACV loaded in the ND system. The chitosan-shelled ND exhibited an average diameter of about 400 nm and a VACV encapsulation efficiency of approximately 91% and was characterized by a prolonged and sustained release of VACV. Moreover, a modification of chitosan shell with an anionic cyclodextrin, sulfobutyl ether β-cyclodextrin (SBEβCD), as a physical cross-linker, increased the stability and mucoadhesion capability of the nanosystem. Biological experiments showed that SBEβCD-chitosan NDs enhanced VACV antiviral activity against the herpes simplex viruses type 1 and 2, most likely due to the long-term controlled release of VACV loaded in the ND and an improved delivery of the drug in sub-cellular compartments.

Efficient ultrasound-mediated drug delivery to orthotopic liver tumors - Direct comparison of doxorubicin-loaded nanobubbles and microbubbles

Liver metastasis is a major obstacle in treating aggressive cancers, and current therapeutic options often prove insufficient. To overcome these challenges, there has been growing interest in ultrasound-mediated drug delivery using lipid-shelled microbubbles (MBs) and nanobubbles (NBs) as promising strategies for enhancing drug delivery to tumors. Our previous work demonstrated the potential of Doxorubicin-loaded C3F8 NBs (hDox-NB, 280 ± 123 nm) in improving cancer treatment in vitro using low-frequency ultrasound. In this study, we investigated the pharmacokinetics and biodistribution of sonicated hDox-NBs in orthotopic rat liver tumors. We compared their delivery and therapeutic efficiency with size-isolated MBs (hDox-MB, 1104 ± 373 nm). Results showed a similar accumulation of hDox in tumors treated with hDox-MBs and unfocused therapeutic ultrasound (hDox-MB+TUS) and hDox-NB+TUS. However, significantly increased apoptotic cell death in the tumor and fewer off-target apoptotic cells in the normal liver were found upon the treatment with hDox-NB+TUS. The tumor-to-liver apoptotic ratio was elevated 9.4-fold following treatment with hDox-NB+TUS compared to hDox-MB+TUS, suggesting that the therapeutic efficacy and specificity are significantly increased when using hDox-NB+TUS. These findings highlight the potential of this approach as a viable treatment modality for liver tumors. By elucidating the behavior of drug-loaded bubbles in vivo, we aim to contribute to developing more effective liver cancer treatments that could ultimately improve patient outcomes and decrease off-target side effects.

Hypoxia signaling in hepatocellular carcinoma: Challenges and therapeutic opportunities

Hepatocellular carcinoma (HCC) is one of the most common cancers with a relatively high cancer-related mortality. The uncontrolled proliferation of HCC consumes a significant amount of oxygen, causing the development of a hypoxic tumor microenvironment (TME). Hypoxia-inducible factors (HIFs), crucial regulators in the TME, activate several cancer hallmarks leading to the hepatocarcinogenesis of HCC and resistance to current therapeutics. As such, HIFs and their signaling pathways have been explored as potential therapeutic targets for the future management of HCC. This review discusses the current understanding of the structure and function of HIFs and their complex relationship with the various cancer hallmarks. To address tumor hypoxia, this review provides an insight into the various potential novel therapeutic agents for managing HCC, such as hypoxia-activated prodrugs, HIF inhibitors, nanomaterials, antisense oligonucleotides, and natural compounds, that target HIFs/hypoxic signaling pathways in HCC. Because of HCC's relatively high incidence and mortality rates in the past decades, greater efforts should be put in place to explore novel therapeutic approaches to improve the outcome for HCC patients.

Radiation combined with ultrasound and microbubbles: A potential novel strategy for cancer treatment

Cancer is one of the leading causes of death worldwide. Several emerging technologies are helping to battle cancer. Cancer therapies have been effective at killing cancer cells, but a large portion of patients still die to this disease every year. As such, more aggressive treatments of primary cancers are employed and have been shown to be capable of saving a greater number of lives. Recent research advances the field of cancer therapy by employing the use of physical methods to alter tumor biology. It uses microbubbles to enhance radiation effect by damaging tumor vasculature followed by tumor cell death. The technique can specifically target tumor volumes by conforming ultrasound fields capable of microbubbles stimulation and localizing it to avoid vascular damage in surrounding tissues. Thus, this new application of ultrasound-stimulated microbubbles (USMB) can be utilized as a novel approach to cancer therapy by inducing vascular disruption resulting in tumor cell death. Using USMB alongside radiation has showed to augment the anti-vascular effect of radiation, resulting in enhanced tumor response. Recent work with nanobubbles has shown vascular permeation into intracellular space, extending the use of this new treatment method to potentially further improve the therapeutic effect of the ultrasound-based therapy. The significant enhancement of localized tumor cell kill means that radiation-based treatments can be made more potent with lower doses of radiation. This technique can manifest a greater impact on radiation oncology practice by increasing treatment effectiveness significantly while reducing normal tissue toxicity. This review article summarizes the past and recent advances in USMB enhancement of radiation treatments. The review mainly focuses on preclinical findings but also highlights some clinical findings that use USMB as a therapeutic modality in cancer therapy.

Hard-Shelled Glycol Chitosan Nanoparticles for Dual MRI/US Detection of Drug Delivery/Release: A Proof-of-Concept Study

This paper describes a novel nanoformulation for dual MRI/US in vivo monitoring of drug delivery/release. The nanosystem was made of a perfluoropentane core coated with phospholipids stabilized by glycol chitosan crosslinked with triphosphate ions, and it was co-loaded with the prodrug prednisolone phosphate (PLP) and the structurally similar MRI agent Gd-DTPAMA-CHOL. Importantly, the in vitro release of PLP and Gd-DTPAMA-CHOL from the nanocarrier showed similar profiles, validating the potential impact of the MRI agent as an imaging reporter for the drug release. On the other hand, the nanobubbles were also detectable by US imaging both in vitro and in vivo. Therefore, the temporal evolution of both MRI and US contrast after the administration of the proposed nanosystem could report on the delivery and the release kinetics of the transported drug in a given lesion.

Bubble-Based Drug Delivery Systems: Next-Generation Diagnosis to Therapy

Current radiologic and medication administration is systematic and has widespread side effects; however, the administration of microbubbles and nanobubbles (MNBs) has the possibility to provide therapeutic and diagnostic information without the same ramifications. Microbubbles (MBs), for instance, have been used for ultrasound (US) imaging due to their ability to remain in vessels when exposed to ultrasonic waves. On the other hand, nanobubbles (NBs) can be used for further therapeutic benefits, including chronic treatments for osteoporosis and cancer, gene delivery, and treatment for acute conditions, such as brain infections and urinary tract infections (UTIs). Clinical trials are also being conducted for different administrations and utilizations of MNBs. Overall, there are large horizons for the benefits of MNBs in radiology, general medicine, surgery, and many more medical applications. As such, this review aims to evaluate the most recent publications from 2016 to 2022 to report the current uses and innovations for MNBs.

Sex blind: bridging the gap between drug exposure and sex-related gene expression in Danio rerio using next-generation sequencing (NGS) data and a literature review to find the missing links in pharmaceutical and environmental toxicology studies

The sex of both humans and Danio rerio has previously been shown to affect the way individuals respond to drug exposure. Genes which allow identification of sex in juvenile zebrafish show potential to reveal these confounding variables between sex in toxicological and preclinical trials but the link between these is so far missing. These sex-specific, early expressed genes where expression is not altered by drug exposure must be carefully selected for this purpose. We aimed to discover genes which can be used in pharmaceutical trials and environmental toxicology studies to uncover sex-related variations in gene expression with drug application using the model organism Danio rerio. Previously published early sex determining genes from King et al. were evaluated as well as additional genes selected from our zebrafish Next-generation sequencing (NGS) data which are known from previously published works not to be susceptible to changes in expression with drug exposure. NGS revealed a further ten female-specific genes (vtg1, cyp17a1, cyp19a1a, igf3, ftz-f1, gdf9, foxl2a, Nr0b1, ipo4, lhcgr) and five male related candidate genes (FKBP5, apobb1, hbaa1, dmrt1, spata6) which are also expressed in juvenile zebrafish, 28 days post fertilisation (dpf). Following this, a literature review was performed to classify which of these early-expressed sex specific genes are already known to be affected by drug exposure in order to determine candidate genes to be used in pharmaceutical trials or environmental toxicology testing studies. Discovery of these early sex-determining genes in Danio rerio will allow identification of sex-related responses to drug testing to improve sex-specific healthcare and the medical treatment of human patients.

Targeted chitosan nanobubbles as a strategy to down-regulate microRNA-17 into B-cell lymphoma models

Introduction

MicroRNAs represent interesting targets for new therapies because their altered expression influences tumor development and progression. miR-17 is a prototype of onco-miRNA, known to be overexpressed in B-cell non-Hodgkin lymphoma (B-NHL) with peculiar clinic-biological features. AntagomiR molecules have been largely studied to repress the regulatory functions of up-regulated onco-miRNAs, but their clinical use is mainly limited by their rapid degradation, kidney elimination and poor cellular uptake when injected as naked oligonucleotides.

Methods

To overcome these problems, we exploited CD20 targeted chitosan nanobubbles (NBs) for a preferential and safe delivery of antagomiR17 to B-NHL cells.

Results

Positively charged 400 nm-sized nanobubbles (NBs) represent a stable and effective nanoplatform for antagomiR encapsulation and specific release into B-NHL cells. NBs rapidly accumulated in tumor microenvironment, but only those conjugated with a targeting system (antiCD20 antibodies) were internalized into B-NHL cells, releasing antagomiR17 in the cytoplasm, both in vitro and in vivo. The result is the down-regulation of miR-17 level and the reduction in tumor burden in a human-mouse B-NHL model, without any documented side effects.

Discussion

Anti-CD20 targeted NBs investigated in this study showed physico-chemical and stability properties suitable for antagomiR17 delivery in vivo and represent a useful nanoplatform to address B-cell malignancies or other cancers through the modification of their surface with specific targeting antibodies.

On Nanobubble Dynamics under an Oscillating Pressure Field during Salting-out Effects and Its DLVO Potential

We have investigated the origin, stability, and nanobubble dynamics under an oscillating pressure field followed by the salting-out effects. The higher solubility ratio (salting-out parameter) of the dissolved gases and pure solvent nucleates nanobubbles during the salting-out effect, and the oscillating pressure field enhances the nanobubble density further as solubility varies linearly with gas pressure by Henry's law. A novel method for refractive index estimation is developed to differentiate nanobubbles and nanoparticles based on the scattering intensity of light. The electromagnetic wave equations have been numerically solved and compared with the Mie scattering theory. The scattering cross-section of the nanobubbles was estimated to be smaller than the nanoparticles. The DLVO potentials of the nanobubbles predict the stable colloidal system. The zeta potential of nanobubbles varied by generating nanobubbles in different salt solutions, and it is characterized by particle tracking, dynamic light scattering, and cryo-TEM. The size of nanobubbles in salt solutions was reported to be higher than that in pure water. The novel mechanical stability model is proposed by considering both ionic cloud and electrostatic pressure at the charged interface. The ionic cloud pressure is derived by electric flux balance, and it is found to be twice the electrostatic pressure. The mechanical stability model for a single nanobubble predicts the existence of stable nanobubbles in the stability map.

Nanobubble technologies: Applications in therapy from molecular to cellular level

Nanobubbles are gaseous entities suspended in bulk liquids that have widespread beneficial usage in many industries. Nanobubbles are already proving to be versatile in furthering the effectiveness of disease treatment on cellular and molecular levels. They are functionalized with biocompatible and stealth surfaces to aid in the delivery of drugs. At the same time, nanobubbles serve as imaging agents due to the echogenic properties of the gas core, which can also be utilized for controlled and targeted delivery. This review provides an overview of the biomedical applications of nanobubbles, covering their preparation and characterization methods, discussing where the research is currently focused, and how they will help shape the future of biomedicine.

Cooking Delicacy with Ice-Nanobubble Isolation Switches Stewing to 'BBQ'

The key role of ice in cooking has been neglected. Here, we found negatively charged bulk nanobubbles (BNBs: average size ~60 nm and zeta potential <-20 mV) can be generated in ice-melted water through freeze/thaw-induced cavitation when we studied a local delicacy, 'ice-stewed mutton'. Freeze/thaw-induced BNBs are so robust that they can, in turn, isolate food from water; in this way, they protect and enhance the delicacy by protecting protein structures and preventing flavorful components from being lost. In comparison to cooking with ordinary water, cooking with ice can switch 'stewing' to 'BBQ', which has been proved experimentally via diverse characterization from the nano to micro scale. This study not only provides a novel mechanism for ice-based cooking but also might shed light on the design of potential applications of BNBs in chemical engineering and biomedicine.

Innovative strategies for photodynamic therapy against hypoxic tumor

Photodynamic therapy (PDT) is applied as a robust therapeutic option for tumor, which exhibits some advantages of unique selectivity and irreversible damage to tumor cells. Among which, photosensitizer (PS), appropriate laser irradiation and oxygen (O₂) are three essential components for PDT, but the hypoxic tumor microenvironment (TME) restricts the O₂ supply in tumor tissues. Even worse, tumor metastasis and drug resistance frequently happen under hypoxic condition, which further deteriorate the antitumor effect of PDT. To enhance the PDT efficiency, critical attention has been received by relieving tumor hypoxia, and innovative strategies on this topic continue to emerge. Traditionally, the O₂ supplement strategy is considered as a direct and effective strategy to relieve TME, whereas it is confronted with great challenges for continuous O₂ supply. Recently, O₂-independent PDT provides a brand new strategy to enhance the antitumor efficiency, which can avoid the influence of TME. In addition, PDT can synergize with other antitumor strategies, such as chemotherapy, immunotherapy, photothermal therapy (PTT) and starvation therapy, to remedy the inadequate PDT effect under hypoxia conditions. In this paper, we summarized the latest progresses in the development of innovative strategies to improve PDT efficacy against hypoxic tumor, which were classified into O₂-dependent PDT, O₂-independent PDT and synergistic therapy. Furthermore, the advantages and deficiencies of various strategies were also discussed to envisage the prospects and challenges in future study.

Smart biomaterials for enhancing cancer therapy by overcoming tumor hypoxia: a review

Hypoxia is a distinctive feature of most solid tumors due to insufficient oxygen supply of the abnormal vasculature, which cannot work with the demands of the fast proliferation of cancer cells. One of the main obstacles to limiting the efficacy of cancer medicines is tumor hypoxia. Thus, oxygen is a vital parameter for controlling the efficacy of different types of cancer therapy, such as chemotherapy (CT), photodynamic therapy (PDT), photothermal therapy (PTT), immunotherapy (IT), and radiotherapy (RT). Numerous technologies have attracted much attention for enhancing oxygen distribution in humans and improving the efficacy of cancer treatment. Such technologies include treatment with hyperbaric oxygen therapy (HBO), delivering oxygen by polysaccharides (e.g., cellulose, gelatin, alginate, and silk) and other biocompatible synthetic polymers (e.g., PMMA, PLA, PVA, PVP and PCL), decreasing oxygen consumption, producing oxygen in situ in tumors, and using polymeric systems as oxygen carriers. Herein, this review provides an overview of the relationship between hypoxia in tumor cells and its role in the limitation of different cancer therapies alongside the numerous strategies for oxygen delivery using polysaccharides and other biomaterials as carriers and for oxygen generation.

Evaluation of the potential of ultrasound-mediated drug delivery for the treatment of ovarian cancer through preclinical studies

Ovarian cancer (OC) has the greatest mortality rate among gynecological cancers, with a five-year survival rate of &lt;50%. Contemporary adjuvant chemotherapy mostly fails in the case of OCs that are refractory, metastatic, recurrent, and drug-resistant. Emerging ultrasound (US)-mediated technologies show remarkable promise in overcoming these challenges. Absorption of US waves by the tissue results in the generation of heat due to its thermal effect causing increased diffusion of drugs from the carriers and triggering sonoporation by increasing the permeability of the cancer cells. Certain frequencies of US waves could also produce a cavitation effect on drug-filled microbubbles (MBs, phospholipid bilayers) thereby generating shear force and acoustic streaming that could assist drug release from the MBs, and promote the permeability of the cell membrane. A new class of nanoparticles that carry therapeutic agents and are guided by US contrast agents for precision delivery to the site of the ovarian tumor has been developed. Phase-shifting of nanoparticles by US sonication has also been engineered to enhance the drug delivery to the ovarian tumor site. These technologies have been used for targeting the ovarian cancer stem cells and protein moieties that are particularly elevated in OCs including luteinizing hormone-releasing hormone, folic acid receptor, and vascular endothelial growth factor. When compared to healthy ovarian tissue, the homeostatic parameters at the tissue microenvironment including pH, oxygen levels, and glucose metabolism differ significantly in ovarian tumors. US-based technologies have been developed to take advantage of these tumor-specific alterations for precision drug delivery. Preclinical efficacy of US-based targeting of currently used clinical chemotherapies presented in this review has the potential for rapid human translation, especially for formulations that use all substances that are deemed to be generally safe by the U.S. Food and Drug Administration.

Enhanced aqueous dissolution of hydrophobic apixaban via direct incorporation of hydrophilic nanographene oxide

In this study, we have directly incorporated nanographene oxide (nGO) into a hydrophobic drug for enhanced dissolution performance through an antisolvent technique. Apixaban (APX) drug composites were synthesized with nGO incorporation ranging from 0.8% to 2.0% concentration. It was observed that the nGO was successfully embedded without any changes to the original drug crystal structure or physical properties. Dissolution of the drug composites was evaluated using US Pharmacopeia Paddle Method (USP 42). The time needed to reach a 50% release (T₅₀) reduced from 106 min to 24 min with the integration of 1.96% nGO in APX and the T₈₀ also dropped accordingly. Alternatively, dissolution rate showed promising performance with increase in nGO concentration. Initial dissolution rate increased dramatically from 74 µg/min to 540 µg/min. Further, work done in intestinal media revealed T₅₀ went from not dissolving to 79.0 min. Decreased lipophilicity or logP value and increased aqueous solubility are both accredited to hydrophilic nGO water dispersion, producing a hydrophilic channel into the drug crystal surfaces through intermolecular interaction. Additionally, physical, and chemical characterizations confirm that hydrophobic apixaban was successfully transformed into a hydrophilic composite, showing potential for this technology to improve dissolution rate of a model hydrophobic compound.

Aqueous dispersions of oxygen nanobubbles for potential application in inhalation therapy

Inhalation is a non-invasive method of local drug delivery to the respiratory system. This study analyzed the potential use of aqueous dispersion of oxygen nanobubbles (ADON) as a drug carrier with the additional function of oxygen supplementation to diseased lungs. The suitability of the membrane-based method of ADON preparation and, next, the stability of ADON properties during storage and after aerosolization in nebulizers of various designs (jet, ultrasonic, and two vibrating mesh devices) was investigated. The increased oxygen content in the aerosol generated in two mesh nebulizers suggests that the proposed concept may be helpful in the oxygen supplementation during drug delivery by aerosol inhalation without using an additional oxygen source. This application can increase the overall effectiveness of lung disease treatment and pulmonary rehabilitation.

Blood–Brain Barrier Permeability Study of Potential Neuroprotective Compounds Recovered From Plants and Agri-Food by-Products

Plants and agri-food by-products represent a wide and renewable source of bioactive compounds with neuroprotective properties. In this research, various green extraction techniques were employed to recover bioactive molecules from Kalanchoe daigremontiana (kalanchoe), epicarp of Cyphomandra betacea (tamarillo), and cooperage woods from Robinia pseudoacacia (acacia) and Nothofagus pumilio (lenga), as well as a reference extract (positive control) from Rosmarinus officinalis L. (rosemary). The neuroprotective capacity of these plant extracts was evaluated in a set of in vitro assays, including enzymatic [acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and lipoxygenase (LOX)] and antioxidant [ABTS, and reactive oxygen and nitrogen species (ROS and RNS)] bioactivity tests. Extracts were also submitted to a parallel artificial membrane permeability assay mimicking the blood–brain barrier (PAMPA-BBB) and to two cell viability assays in HK-2 and SH-SY5Y cell lines. Comprehensive phytochemical profiling based on liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) analysis showed enriched content of phenolic and terpenoid compounds in the target extracts. Moreover, in vitro bioactivity tests showed promising neuroprotective capacity, particularly for supercritical-fluid extraction (SFE) extract from acacia (ABTS IC₅₀ = 0.11 μg ml⁻¹; ROS IC₅₀ = 1.56 μg ml⁻¹; AChE IC₅₀ = 4.23 μg ml⁻¹; BChE IC₅₀ = 1.20 μg ml⁻¹; and LOX IC₅₀ = 4.37 μg ml⁻¹), whereas PAMPA-BBB assays revealed high perfusion capacity of some representative compounds, such as phenolic acids or flavonoids. Regarding cytotoxic assays, tamarillo and rosemary SFE extracts can be considered as non-toxic, acacia SFE extract and lenga pressurized liquid extraction (PLE) extract as mild-cytotoxic, and kalanchoe as highly toxic extracts. The obtained results demonstrate the great potential of the studied biomass extracts to be transformed into valuable food additives, food supplements, or nutraceuticals with promising neuroprotective properties.

Ultrasound-assisted brain delivery of nanomedicines for brain tumor therapy: advance and prospect

Nowadays, brain tumors are challenging problems, and the key of therapy is ensuring therapeutic drugs cross the blood-brain barrier (BBB) effectively. Although the efficiency of drug transport across the BBB can be increased by innovating and modifying nanomedicines, they exert insufficient therapeutic effects on brain tumors due to the complex environment of the brain. It is worth noting that ultrasound combined with the cavitation effect of microbubbles can assist BBB opening and enhance brain delivery of nanomedicines. This ultrasound-assisted brain delivery (UABD) technology with related nanomedicines (UABD nanomedicines) can safely open the BBB, facilitate the entry of drugs into the brain, and enhance the therapeutic effect on brain tumors. UABD nanomedicines, as the main component of UABD technology, have great potential in clinical application and have been an important area of interest in the field of brain tumor therapy. However, research on UABD nanomedicines is still in its early stages despite the fact that they have been associated with many disciplines, including material science, brain science, ultrasound, biology, and medicine. Some aspects of UABD theory and technology remain unclear, especially the mechanisms of BBB opening, relationship between materials of nanomedicines and UABD technology, cavitation and UABD nanomedicines design theories. This review introduces the research status of UABD nanomedicines, investigates their properties and applications of brain tumor therapy, discusses the advantages and drawbacks of UABD nanomedicines for the treatment of brain tumors, and offers their prospects. We hope to encourage researchers from various fields to participate in this area and collaborate on developing UABD nanomedicines into powerful tools for brain tumor therapy.

Exploring chitosan-shelled nanobubbles to improve HER2 + immunotherapy via dendritic cell targeting

Immunotherapy is a valuable approach to cancer treatment as it is able to activate the immune system. However, the curative methods currently in clinical practice, including immune checkpoint inhibitors, present some limitations. Dendritic cell vaccination has been investigated as an immunotherapeutic strategy, and nanotechnology-based delivery systems have emerged as powerful tools for improving immunotherapy and vaccine development. A number of nanodelivery systems have therefore been proposed to promote cancer immunotherapy. This work aims to design a novel immunotherapy nanoplatform for the treatment of HER2 + breast cancer, and specially tailored chitosan-shelled nanobubbles (NBs) have been developed for the delivery of a DNA vaccine. The NBs have been functionalized with anti-CD1a antibodies to target dendritic cells (DCs). The NB formulations possess dimensions of approximately 300 nm and positive surface charge, and also show good physical stability up to 6 months under storage at 4 °C. In vitro characterization has confirmed that these NBs are capable of loading DNA with good encapsulation efficiency (82%). The antiCD1a-functionalized NBs are designed to target DCs, and demonstrated the ability to induce DC activation in both human and mouse cell models, and also elicited a specific immune response that was capable of slowing tumor growth in mice in vivo. These findings are the proof of concept that loading a tumor vaccine into DC-targeted chitosan nanobubbles may become an attractive nanotechnology approach for the future immunotherapeutic treatment of cancer.

Evaluation of the dermal irritation and skin sensitization due to thiocolchicoside transdermal drug delivery system

The skin irritation and sensitization potential of the new transdermal patch of the Thiocolchicoside formulated with Dura 87-6908 was evaluated on the rabbits and guinea pig as per the standard guidelines of OECD. Skin irritation test was performed on the rabbits by applying the placebo patch for 72 hours and dermal reactions like edema, erythema were noted. No clinical signs or dermal reactions were observed in the rabbits. Sensitization potential was measure on the guinea pig and animal was challenged to transdermal therapeutic system of the Thiocolchicoside, negative control group while group exposed to CDNB produced the sensitization reactions. These findings proved that Thiocolchicoside does not produce any dermal toxicity, irritation and sensitization and hence it is safe for dermal use.

Environmental Exploration of Ultra-Dense Nanobubbles: Rethinking Sustainability

Nanobubbles are nanoscopic gaseous domains than can exist on solid surfaces or in bulk liquids. They have attracted significant attention in the last decade due to their long-time (meta)stability and ready potential for real-world applications, especially in environmental engineering and more sustainable ecosystems, water treatment, irrigation, and crop growth. After reviewing important nano-bubble science and activity, with some of the latest promising results in agriculture, we point out important directions in applications of nano-bubble phenomena for boosting sustainability, with viewpoints on how to revolutionise best-practice environmental and green sustainability, taking into account economic drivers and impacts. More specifically, it is pointed out how nanobubbles may be used as delivery vehicles, or “nano-carriers”, for nutrients or other agents to specific targets in a variety of ecosystems of environmental relevance, and how core this is to realising a vision of ultra-dense NBs in shaping a positive and lasting impact on ecosystems and our natural environment.

Mechanistic Insights and Therapeutic Delivery through Micro/Nanobubble-Assisted Ultrasound

Ultrasound with low frequency (20–100 kHz) assisted drug delivery has been widely investigated as a non-invasive method to enhance the permeability and retention effect of drugs. The functional micro/nanobubble loaded with drugs could provide an unprecedented opportunity for targeted delivery. Then, ultrasound with higher intensity would locally burst bubbles and release agents, thus avoiding side effects associated with systemic administration. Furthermore, ultrasound-mediated destruction of micro/nanobubbles can effectively increase the permeability of vascular membranes and cell membranes, thereby not only increasing the distribution concentration of drugs in the interstitial space of target tissues but also promoting the penetration of drugs through cell membranes into the cytoplasm. These advancements have transformed ultrasound from a purely diagnostic utility into a promising theragnostic tool. In this review, we first discuss the structure and generation of micro/nanobubbles. Second, ultrasound parameters and mechanisms of therapeutic delivery are discussed. Third, potential biomedical applications of micro/nanobubble-assisted ultrasound are summarized. Finally, we discuss the challenges and future directions of ultrasound combined with micro/nanobubbles.

Ultrasound-Responsive Nrf2-Targeting siRNA-Loaded Nanobubbles for Enhancing the Treatment of Melanoma

The siRNA-mediated inhibition of nuclear factor E2-related factor 2 (Nrf2) can be an attractive approach to overcome chemoresistance in various malignant tumors, including melanoma. This work aims at designing a new type of chitosan-shelled nanobubble for the delivery of siRNA against Nrf2 in combination with an ultrasound. A new preparation method based on a water-oil-water (W/O/W) double-emulsion was purposely developed for siRNA encapsulation in aqueous droplets within a nanobubble core. Stable, very small NB formulations were obtained, with sizes of about 100 nm and a positive surface charge. siRNA was efficiently loaded in NBs, reaching an encapsulation efficiency of about 90%. siNrf2-NBs downregulated the target gene in M14 cells, sensitizing the resistant melanoma cells to the cisplatin treatment. The combination with US favored NB cell uptake and transfection efficiency. Based on the results, nanobubbles have shown to be a promising US responsive tool for siRNA delivery, able to overcome chemoresistance in melanoma cancer cells.

In-silico Screening of Phytoconstituents on Wound Healing Targets-Approaches and Current Status

Over recent years, there has been tremendous research focused on the effective utilization of natural products in wound management. Natural or herbal products contain several phytoconstituents that may act on various stages in wound healing and thereby provide a multi-targeted approach especially in the treatment of chronic wounds. Currently, attempts have been made to screen the phytoconstituents present in herbs on various targets involved in wound healing. This review includes a systematic evaluation of scientific reports by various groups of researchers on the herbals evaluated for wound management, their phytochemical profiling, pre-clinical studies, and molecular modeling studies. Various wound targets discussed include Interleukin-1, Interleukin-6, Tumor necrosis factor-α (TNF-α), Thymosin beta-4 (Tβ-4) that regulate the early inflammatory stage and the novel T cell immune response cDNA 7(TIRC7) that regulates angiogenesis. Also, neuropeptides P and Y act on the inflammatory, migratory, and proliferation phases, and growth factors like vascular endothelial growth factor family (VEGF) and placental growth factor family (PGF) are involved in angiogenesis, while the role of Fibroblast growth factor in tissue remodeling is discussed. As many of the natural products include polyherbal systems, this approach can help in the judicious selection of a combination of herbs that will act on multiple targets in the wound healing process and provide a multi-factorial approach in wound management.

Review of Oxygenation with Nanobubbles: Possible Treatment for Hypoxic COVID-19 Patients

The coronavirus disease (COVID-19) pandemic, which has spread around the world, caused the death of many affected patients, partly because of the lack of oxygen arising from impaired respiration or blood circulation. Thus, maintaining an appropriate level of oxygen in the patients' blood by devising alternatives to ventilator systems is a top priority goal for clinicians. The present review highlights the ever-increasing application of nanobubbles (NBs), miniature gaseous vesicles, for the oxygenation of hypoxic patients. Oxygen-containing NBs can exert a range of beneficial physiologic and pharmacologic effects that include tissue oxygenation, as well as tissue repair mechanisms, antiinflammatory properties, and antibacterial activity. In this review, we provide a comprehensive survey of the application of oxygen-containing NBs, with a primary focus on the development of intravenous platforms. The multimodal functions of oxygen-carrying NBs, including antimicrobial, antiinflammatory, drug carrying, and the promotion of wound healing are discussed, including the benefits and challenges of using NBs as a treatment for patients with acute hypoxemic respiratory failure, particularly due to COVID-19.

Injectable Hydrogel for Synergetic Low Dose Radiotherapy, Chemodynamic Therapy and Photothermal Therapy

Higher doses of radiotherapy (RT) are associated with resistance induction, therefore highly selective and controllable radiosensitizers are urgently needed. To address this issue, we developed a FeGA-based injectable hydrogel system (FH) that can be used in combination with low-dose radiation. Our FH can deliver FeGA directly to the tumor site via intratumoral injection, where it is a reservoir-based system to conserve FeGA. The photothermal properties of FeGA steadily dissolve FH under laser irradiation, and, simultaneously, FeGA reacts with a large amount of H2O2 in the cell to produce OH (Fenton reaction) which is highly toxic to mitochondria, rendering the cell inactive and reducing radiotherapy resistance. In vivo and in vitro studies suggest that combining the FH and NIR irradiation with RT (2Gy) can significantly reduce tumor proliferation without side effects such as inflammation. To conclude, this is the first study to achieve combined chemodynamic therapy (CDT) and photothermal therapy (PTT) in situ treatment, and the best therapeutic effect can be obtained with a low-dose radiation combination, thus expanding the prospects of FeGA-based tumor therapy.

Harnessing the combined potential of cancer immunotherapy and nanomedicine: A new paradigm in cancer treatment

Cancer immunotherapy has recently emerged as a rising star due to its ability to activate patients' immune systems to fight tumors and prevent relapse. Conversely, the interest in cancer nanomedicine has seemingly waned due to its lackluster clinical translation. Despite being hailed as a game-changer in oncology, cancer immunotherapy still faces numerous challenges. Combining both entities together has thus been one among several solutions proposed to circumvent these challenges. This solution has since gained traction and has also led to a renaissance of cancer nanomedicine. While most combinations are currently experimental at best, some have progressed on to clinical trials. This review thus seeks to examine the advantages and disadvantages of integrating both modalities as a cancer treatment. The opportunities, challenges and future directions of this emerging field will also be explored with the hope that such a combination will lead to a paradigm shift in cancer treatments.

Theranostic nanobubbles towards smart nanomedicines

Targeted therapy and early accurate detection of malignant lesions are essential for the effectiveness of treatment and prognosis in cancer patients. The development of gaseous system as a versatile platform for the fabricated nanobubbles, has attracted much interest in improving the efficacy of ultrasound therapeutic, diagnostic, and theranostic platforms. Nano-sized bubble, as an ultrasound contrast agent, with spherical gas-filled structures exhibited contrast enhancement capability due to their inherent EPR effect. Additionally, nanobubbles exhibited good stability with extended retention time in the blood stream. The current review summarized various nanobubbles and discussed about the crucial parameters affecting the stability of ultrafine bubbles. Furthermore, therapeutic and theranostic gaseous systems for fighting against cancer were described.

Nano-engineered tools in the diagnosis, therapeutics, prevention, and mitigation of SARS-CoV-2

The recent outbreak of SARS-CoV-2 has forever altered mankind resulting in the COVID-19 pandemic. This respiratory virus further manifests into vital organ damage, resulting in severe post COVID-19 complications. Nanotechnology has been moonlighting in the scientific community to combat several severe diseases. This review highlights the triune of the nano-toolbox in the areas of diagnostics, therapeutics, prevention, and mitigation of SARS-CoV-2. Nanogold test kits have already been on the frontline of rapid detection. Breath tests, magnetic nanoparticle-based nucleic acid detectors, and the use of Raman Spectroscopy present myriads of possibilities in developing point of care biosensors, which will ensure sensitive, affordable, and accessiblemass surveillance. Most of the therapeutics are trying to focus on blocking the viral entry into the cell and fighting with cytokine storm, using nano-enabled drug delivery platforms. Nanobodies and mRNA nanotechnology with lipid nanoparticles (LNPs) as vaccines against S and N protein have regained importance. All the vaccines coming with promising phase 3 clinical trials have used nano-delivery systems for delivery of vaccine-cargo, which are currently administered widely in many countries. The use of chemically diverse metal, carbon and polymeric nanoparticles, nanocages and nanobubbles demonstrate opportunities to develop anti-viral nanomedicine. In order to prevent and mitigate the viral spread, high-performance charged nanofiber filters, spray coating of nanomaterials on surfaces, novel materials for PPE kits and facemasks have been developed that accomplish over 90% capture of airborne SARS-CoV-2. Nano polymer-based disinfectants are being tested to make smart-transport for human activities. Despite the promises of this toolbox, challenges in terms of reproducibility, specificity, efficacy and emergence of new SARS-CoV-2 variants are yet to overcome.

Developing Actively Targeted Nanoparticles to Fight Cancer: Focus on Italian Research

Active targeting is a valuable and promising approach with which to enhance the therapeutic efficacy of nanodelivery systems, and the development of tumor-targeted nanoparticles has therefore attracted much research attention. In this field, the research carried out in Italian Pharmaceutical Technology academic groups has been focused on the development of actively targeted nanosystems using a multidisciplinary approach. To highlight these efforts, this review reports a thorough description of the last 10 years of Italian research results on the development of actively targeted nanoparticles to direct drugs towards different receptors that are overexpressed on cancer cells or in the tumor microenvironment. In particular, the review discusses polymeric nanocarriers, liposomes, lipoplexes, niosomes, solid lipid nanoparticles, squalene nanoassemblies and nanobubbles. For each nanocarrier, the main ligands, conjugation strategies and target receptors are described. The literature indicates that polymeric nanoparticles and liposomes stand out as key tools for improving specific drug delivery to the site of action. In addition, solid lipid nanoparticles, squalene nanoparticles and nanobubbles have also been successfully proposed. Taken together, these strategies all offer many platforms for the design of nanocarriers that are suitable for future clinical translation.

Xenon Nanobubbles for the Image-Guided Preemptive Treatment of Acute Ischemic Stroke via Neuroprotection and Microcirculatory Restoration

Early lesion site diagnosis and neuroprotection are crucial to the theranostics of acute ischemic stroke. Xenon (Xe), as a nontoxic gaseous neuroprotectant, holds great promise for ischemic stroke therapy. In this study, Xe-encapsulated lipid nanobubbles (Xe-NBs) have been prepared for the real-time ultrasound image-guided preemptive treatment of the early stroke. The lipids are self-assembled at the interface of free Xe bubbles, and the mean diameter of Xe-NBs is 225 ± 11 nm with a Xe content of 73 ± 2 μL/mL. The in vitro results show that Xe-NBs can protect oxygen/glucose-deprived PC12 cells against apoptosis and oxidative stress. Based on the ischemic stroke mice model, the biodistribution, timely ultrasound imaging, and the therapeutic effects of Xe-NBs for stroke lesions were investigated in vivo. The accumulation of Xe-NBs to the ischemic lesion endows ultrasound contrast imaging with the lesion area. The cerebral blood flow measurement indicates that the administration of Xe-NBs can improve microcirculatory restoration, resulting in reduced acute microvascular injury in the lesion area. Furthermore, local delivery of therapeutic Xe can significantly reduce the volume of cerebral infarction and restore the neurological function with reduced neuron injury against apoptosis. Therefore, Xe-NBs provide a novel nanosystem for the safe and rapid theranostics of acute ischemic stroke, which is promising to translate into the clinical management of stroke.

Ultrasound-Enabled Therapeutic Delivery and Regenerative Medicine: Physical and Biological Perspectives

The role of ultrasound in medicine and biological sciences is expanding rapidly beyond its use in conventional diagnostic imaging. Numerous studies have reported the effects of ultrasound on cellular and tissue physiology. Advances in instrumentation and electronics have enabled successful in vivo applications of therapeutic ultrasound. Despite path breaking advances in understanding the biophysical and biological mechanisms at both microscopic and macroscopic scales, there remain substantial gaps. With the progression of research in this area, it is important to take stock of the current understanding of the field and to highlight important areas for future work. We present herein key developments in the biological applications of ultrasound especially in the context of nanoparticle delivery, drug delivery, and regenerative medicine. We conclude with a brief perspective on the current promise, limitations, and future directions for interfacing ultrasound technology with biological systems, which could provide guidance for future investigations in this interdisciplinary area.

Therapeutic oxygen delivery by perfluorocarbon-based colloids

After the protocol-related indecisive clinical trial of Oxygent, a perfluorooctylbromide/phospholipid nanoemulsion, in cardiac surgery, that often unduly assigned the observed untoward effects to the product, the development of perfluorocarbon (PFC)-based O₂ nanoemulsions ("blood substitutes") has come to a low. Yet, significant further demonstrations of PFC O₂-delivery efficacy have continuously been reported, such as relief of hypoxia after myocardial infarction or stroke; protection of vital organs during surgery; potentiation of O₂-dependent cancer therapies, including radio-, photodynamic-, chemo- and immunotherapies; regeneration of damaged nerve, bone or cartilage; preservation of organ grafts destined for transplantation; and control of gas supply in tissue engineering and biotechnological productions. PFC colloids capable of augmenting O₂ delivery include primarily injectable PFC nanoemulsions, microbubbles and phase-shift nanoemulsions. Careful selection of PFC and other colloid components is critical. The basics of O₂ delivery by PFC nanoemulsions will be briefly reminded. Improved knowledge of O₂ delivery mechanisms has been acquired. Advanced, size-adjustable O₂-delivering nanoemulsions have been designed that have extended room-temperature shelf-stability. Alternate O₂ delivery options are being investigated that rely on injectable PFC-stabilized microbubbles or phase-shift PFC nanoemulsions. The latter combine prolonged circulation in the vasculature, capacity for penetrating tumor tissues, and acute responsiveness to ultrasound and other external stimuli. Progress in microbubble and phase-shift emulsion engineering, control of phase-shift activation (vaporization), understanding and control of bubble/ultrasound/tissue interactions is discussed. Control of the phase-shift event and of microbubble size require utmost attention. Further PFC-based colloidal systems, including polymeric micelles, PFC-loaded organic or inorganic nanoparticles and scaffolds, have been devised that also carry substantial amounts of O₂. Local, on-demand O₂ delivery can be triggered by external stimuli, including focused ultrasound irradiation or tumor microenvironment. PFC colloid functionalization and targeting can help adjust their properties for specific indications, augment their efficacy, improve safety profiles, and expand the range of their indications. Many new medical and biotechnological applications involving fluorinated colloids are being assessed, including in the clinic. Further uses of PFC-based colloidal nanotherapeutics will be briefly mentioned that concern contrast diagnostic imaging, including molecular imaging and immune cell tracking; controlled delivery of therapeutic energy, as for noninvasive surgical ablation and sonothrombolysis; and delivery of drugs and genes, including across the blood-brain barrier. Even when the fluorinated colloids investigated are designed for other purposes than O₂ supply, they will inevitably also carry and deliver a certain amount of O₂, and may thus be considered for O₂ delivery or co-delivery applications. Conversely, O₂-carrying PFC nanoemulsions possess by nature a unique aptitude for ¹⁹F MR imaging, and hence, cell tracking, while PFC-stabilized microbubbles are ideal resonators for ultrasound contrast imaging and can undergo precise manipulation and on-demand destruction by ultrasound waves, thereby opening multiple theranostic opportunities.

Stimuli-responsive nanobubbles for biomedical applications

Stimuli-responsive nanobubbles have received increased attention for their application in spatial and temporal resolution of diagnostic techniques and therapies, particularly in multiple imaging methods, and they thus have significant potential for applications in the field of biomedicine. This review presents an overview of the recent advances in the development of stimuli-responsive nanobubbles and their novel applications. Properties of both internal- and external-stimuli responsive nanobubbles are highlighted and discussed considering the potential features required for biomedical applications. Furthermore, the methods used for synthesis and characterization of nanobubbles are outlined. Finally, novel biomedical applications are proposed alongside the advantages and shortcomings inherent to stimuli-responsive nanobubbles.