Mechanical nanosurgery of chemoresistant glioblastoma using magnetically controlled carbon nanotubes

Nanotechnology in cancer treatment: revolutionizing strategies against drug resistance

A notable increase in cancer-related fatalities and morbidity worldwide is attributed to drug resistance. The factors contributing to drug resistance include drug efflux via ABC transporters, apoptosis evasion, epigenetic alterations, DNA repair mechanisms, and the tumor microenvironment, among others. Systemic toxicities and resistance associated with conventional cancer diagnostics and therapies have led to the development of alternative approaches, such as nanotechnology, to enhance diagnostic precision and improve therapeutic outcomes. Nanomaterial, including carbon nanotubes, dendrimers, polymeric micelles, and liposomes, have shown significant benefits in cancer diagnosis and treatment due to their unique physicochemical properties, such as biocompatibility, stability, enhanced permeability, retention characteristics, and targeted delivery. Building on these advantages, this review is conducted through comprehensive analysis of recent literature to explore the principal mechanisms of drug resistance, the potential of nanomaterials to revolutionize selective drug delivery and cancer treatment. Additionally, the strategies employed by nanomaterials to overcome drug resistance in tumors, such as efflux pump inhibition, multidrug loading, targeted delivery to the tumor microenvironment, and gene silencing therapies are discussed in detail. Furthermore, we examine the challenges associated with nanomaterials that limit their application and impede their transition to clinical use.

Effective approaches in conquering chemoresistance of glioblastoma: potential for nanoformulations

Glioblastoma Multiforme is an aggressive and complex cancer affecting mostly elderly patients above the age of 60 years. Originally classified as the fourth stage of glioma, it has an abysmal prognosis along with limited therapeutic options. Surgical removal of tumors, radiotherapy, and chemotherapy are prevalent treatment strategies with numerous therapeutic obstacles, including undefined boundary of tumor mass leaving traces even after excision, chances of secondary cancer formation, and presence of blood-brain barrier. These blood-brain and blood-brain tumor barriers actively restrict the permeability of many molecules from blood circulation to enter the central nervous system. Therefore, many conventional antineoplastic drugs fail to reach the tumor periphery except temozolomide. Meanwhile, active stem cells in the tumor microenvironment, genetic mutation inducing tumor growth, and epigenetic pattern alteration make this cancer chemoresistant. Our review delineates the recent approaches to resensitize the existing clinical drugs through specifically designed nanoformulations. Nanoparticles with modified physiological characteristics and modified through technological parameters can reduce the tumor's stemness, which increases tumor cells' apoptosis rate. Moreover, these nanoparticles can efficiently traverse the blood-brain barrier and escape from endosomal degradation with minimum toxicological impact. Overall, this review discusses the cancer chemoresistance phenomena and related pathways and highlights the potential of nanoformulation in reversing chemoresistance. Also, the existing limitations of this unique approach and suggestions are discussed at the end of the article, which may facilitate the identification of new directions for advancement of the nanoparticle-mediated reversal of chemoresistance.

Magnetically actuated dexterous tools for minimally invasive operation inside the brain

Operating in the brain for deep-seated tumors or surgical targets for epilepsy is technically demanding and normally requires a large craniotomy with its attendant risk and morbidity. Neuroendoscopic surgery has the potential to reduce risk and morbidity by permitting surgical access through a small incision with burr hole and a narrow corridor through the brain. However, current endoscopic neurosurgical tools are straight and rigid and lack dexterity, hindering their adoption for neuroendoscopic procedures. We propose a class of robotic neurosurgical tools that have magnetically actuated wristed end effectors small enough to fit through a neuroendoscope working channel. The tools were less than 3.2 millimeters in overall diameter and contained embedded permanent magnets that allowed wireless actuation with magnetic fields. Three magnetic tools are presented: a two-degrees-of-freedom (DoFs) wristed gripper, a one-DoF pivoting scalpel, and a one-DoF twisted string-actuated forceps. This work evaluated the feasibility of these tools for completing minimally invasive neurosurgical resection and cutting tasks. Experimental tests on a silicone brain phantom showed that the tools could reach the ventricle area for simulated tumor removal and access a section of the corpus callosotomy for a simulated tissue-severing procedure in epilepsy treatment. Integration of the magnetic end effectors with a concentric tube robot as a hybrid steerable surgical robotic system enabled in vivo experiments on piglets. These experiments show that wireless magnetic tools could perform essential neurosurgical tasks, including gripping, cutting, and biopsy on living brain tissue, suggesting their potential for clinical applications.

Brain-targeting drug delivery systems: The state of the art in treatment of glioblastoma

Glioblastoma (GBM) is the most prevalent primary malignant brain tumor, characterized by a high mortality rate and a poor prognosis. The blood-brain barrier (BBB) and the blood-tumor barrier (BTB) present significant obstacles to the efficacy of tumor-targeted pharmacotherapy, thereby impeding the therapeutic potential of numerous candidate drugs. Targeting delivery of adequate doses of drug across the BBB to treat GBM has become a prominent research area in recent years. This emphasis has driven the exploration and evaluation of diverse technologies for GBM pharmacotherapy, with some already undergoing clinical trials. This review provides a thorough overview of recent advancements and challenges in targeted drug delivery for GBM treatment. It specifically emphasizes systemic drug administration strategies to assess their potential and limitations in GBM treatment. Furthermore, this review highlights promising future research directions in the development of intelligent drug delivery systems aimed at overcoming current challenges and enhancing therapeutic efficacy against GBM. These advancements not only support foundational research on targeted drug delivery systems for GBM but also offer methodological approaches for future clinical applications.

Advancing brain immunotherapy through functional nanomaterials

Glioblastoma (GBM), a highly aggressive brain tumor, poses significant treatment challenges due to its highly immunosuppressive microenvironment and the brain immune privilege. Immunotherapy activating the immune system and T lymphocyte infiltration holds great promise against GBM. However, the brain's low immunogenicity and the difficulty of crossing the blood-brain barrier (BBB) hinder therapeutic efficacy. Recent advancements in immune-actuated particles for targeted drug delivery have shown the potential to overcome these obstacles. These particles interact with the BBB by rapidly and reversibly disrupting its structure, thereby significantly enhancing targeting and penetrating delivery. The BBB targeting also minimizes potential long-term damage. At GBM, the particles demonstrated effective chemotherapy, chemodynamic therapy, photothermal therapy (PTT), photodynamic therapy (PDT), radiotherapy, or magnetotherapy, facilitating tumor disruption and promoting antigen release. Additionally, components of the delivery system retained autologous tumor-associated antigens and presented them to dendritic cells (DCs), ensuring prolonged immune activation. This review explores the immunosuppressive mechanisms of GBM, existing therapeutic strategies, and the role of nanomaterials in enhancing immunotherapy. We also discuss innovative particle-based approaches designed to traverse the BBB by mimicking innate immune functions to improve treatment outcomes for brain tumors.

Swarm Autonomy: From Agent Functionalization to Machine Intelligence

Swarm behaviors are common in nature, where individual organisms collaborate via perception, communication, and adaptation. Emulating these dynamics, large groups of active agents can self-organize through localized interactions, giving rise to complex swarm behaviors, which exhibit potential for applications across various domains. This review presents a comprehensive summary and perspective of synthetic swarms, to bridge the gap between the microscale individual agents and potential applications of synthetic swarms. It is begun by examining active agents, the fundamental units of synthetic swarms, to understand the origins of their motility and functionality in the presence of external stimuli. Then inter-agent communications and agent-environment communications that contribute to the swarm generation are summarized. Furthermore, the swarm behaviors reported to date and the emergence of machine intelligence within these behaviors are reviewed. Eventually, the applications enabled by distinct synthetic swarms are summarized. By discussing the emergent machine intelligence in swarm behaviors, insights are offered into the design and deployment of autonomous synthetic swarms for real-world applications.

Magneto-Thermal Hydrogel Swarms for Targeted Lesion Sealing

Magnetic microswarms capable of performing navigation to targeted lesions show great potential for in vivo medical applications. However, using the swarms for lesion cavity filling encounters challenges from precise delivery and sealing. Herein, this work develops a magneto-thermal hydrogel swarm consisting of magnetic hydrogel particles, which can perform phase transition induced by temperature change. The particles are prepared using a temperature-responsive hydrogel matrix, tissue adhesive monomers, and magnetic microparticles. The swarms can be remolded to various shapes, and it can be used to seal perforation in phantom and gastric tissue. The swarms can also serve as drug carriers, and their drug release profiles induced by temperature changes are characterized. Finally, the targeted delivery, adaptive filling, and sealing of a gastric ulcer using the swarms are achieved in ex vivo and in vivo environments.

Imaging-guided bioresorbable acoustic hydrogel microrobots

Micro- and nanorobots excel in navigating the intricate and often inaccessible areas of the human body, offering immense potential for applications such as disease diagnosis, precision drug delivery, detoxification, and minimally invasive surgery. Despite their promise, practical deployment faces hurdles, including achieving stable propulsion in complex in vivo biological environments, real-time imaging and localization through deep tissue, and precise remote control for targeted therapy and ensuring high therapeutic efficacy. To overcome these obstacles, we introduce a hydrogel-based, imaging-guided, bioresorbable acoustic microrobot (BAM) designed to navigate the human body with high stability. Constructed using two-photon polymerization, a BAM comprises magnetic nanoparticles and therapeutic agents integrated into its hydrogel matrix for precision control and drug delivery. The microrobot features an optimized surface chemistry with a hydrophobic inner layer to substantially enhance microbubble retention in biofluids with multiday functionality and a hydrophilic outer layer to minimize aggregation and promote timely degradation. The dual-opening bubble-trapping cavity design enables a BAM to maintain consistent and efficient acoustic propulsion across a range of biological fluids. Under focused ultrasound stimulation, the entrapped microbubbles oscillate and enhance the contrast for real-time ultrasound imaging, facilitating precise tracking and control of BAM movement through wireless magnetic navigation. Moreover, the hydrolysis-driven biodegradability of BAMs ensures its safe dissolution after treatment, posing no risk of long-term residual harm. Thorough in vitro and in vivo experimental evidence demonstrates the promising capabilities of BAMs in biomedical applications. This approach shows promise for advancing minimally invasive medical interventions and targeted therapeutic delivery.

Current Non-Metal Nanoparticle-Based Therapeutic Approaches for Glioblastoma Treatment

The increase in the variety of nano-based tools offers new possibilities to approach the therapy of poorly treatable tumors, which includes glioblastoma multiforme (GBM; a primary brain tumor). The available nanocomplexes exhibit great potential as vehicles for the targeted delivery of anti-GBM compounds, including chemotherapeutics, nucleic acids, and inhibitors. The main advantages of nanoparticles (NPs) include improved drug stability, increased penetration of the blood-brain barrier, and better precision of tumor targeting. Importantly, alongside their drug-delivery ability, NPs may also present theranostic properties, including applications for targeted imaging or photothermal therapy of malignant brain cells. The available NPs can be classified into two categories according to their core, which can be metal or non-metal based. Among non-metal NPs, the most studied in regard to GBM treatment are exosomes, liposomes, cubosomes, polymeric NPs, micelles, dendrimers, nanogels, carbon nanotubes, and silica- and selenium-based NPs. They are characterized by satisfactory stability and biocompatibility, limited toxicity, and high accumulation in the targeted tumor tissue. Moreover, they can be easily functionalized for the improved delivery of their cargo to GBM cells. Therefore, the non-metal NPs discussed here, offer a promising approach to improving the treatment outcomes of aggressive GBM tumors.

Integrated Cross-Scale Manipulation and Modulable Encapsulation of Cell-Laden Hydrogel for Constructing Tissue-Mimicking Microstructures

Engineered microstructures that mimic in vivo tissues have demonstrated great potential for applications in regenerative medicine, drug screening, and cell behavior exploration. However, current methods for engineering microstructures that mimic the multi-extracellular matrix and multicellular features of natural tissues to realize tissue-mimicking microstructures in vitro remain insufficient. Here, we propose a versatile method for constructing tissue-mimicking heterogeneous microstructures by orderly integration of macroscopic hydrogel exchange, microscopic cell manipulation, and encapsulation modulation. First, various cell-laden hydrogel droplets are manipulated at the millimeter scale using electrowetting on dielectric to achieve efficient hydrogel exchange. Second, the cells are manipulated at the micrometer scale using dielectrophoresis to adjust their density and arrangement within the hydrogel droplets. Third, the photopolymerization of these hydrogel droplets is triggered in designated regions by dynamically modulating the shape and position of the excitation ultraviolet beam. Thus, heterogeneous microstructures with different extracellular matrix geometries and components were constructed, including specific cell densities and patterns. The resulting heterogeneous microstructure supported long-term culture of hepatocytes and fibroblasts with high cell viability (over 90%). Moreover, the density and distribution of the 2 cell types had significant effects on the cell proliferation and urea secretion. We propose that our method can lead to the construction of additional biomimetic heterogeneous microstructures with unprecedented potential for use in future tissue engineering applications.

Nanotechnology as a new strategy for the diagnosis and treatment of gliomas

Glioma is the most common malignant tumor of the central nervous system (CNS), and is characterized by high aggressiveness and a high recurrence rate. Currently, the main treatments for gliomas include surgical resection, temozolomide chemotherapy and radiotherapy. However, the prognosis of glioma patients after active standardized treatment is still poor, especially for glioblastoma (GBM); the median survival is still only 14.6 months, and the 5-year survival rate is only 4-5%. The current challenges in glioma treatment include difficulty in complete surgical resection, poor blood‒brain barrier (BBB) drug permeability, therapeutic resistance, and difficulty in tumor-specific targeting. In recent years, the rapid development of nanotechnology has provided new directions for diagnosing and treating gliomas. Nanoparticles (NPs) are characterized by excellent surface tunability, precise targeting, excellent biocompatibility, and high safety. In addition, NPs can be used for gene therapy, photodynamic therapy, and antiangiogenic therapy and can be combined with biomaterials for thermotherapy. In recent decades, breakthroughs in diagnosing and treating gliomas have been made with various functional NPs, and NPs are expected to become a new strategy for glioma diagnosis and treatment. In this paper, we review the main obstacles in the treatment of glioma and discuss the potential and challenges of the latest nanotechnology in the diagnosis and treatment of glioma.

Recent advances in targeted drug delivery for the treatment of glioblastoma

Glioblastoma multiforme (GBM) is one of the highly malignant brain tumors characterized by significant morbidity and mortality. Despite the recent advancements in the treatment of GBM, major challenges persist in achieving controlled drug delivery to tumors. The management of GBM poses considerable difficulties primarily due to unresolved issues in the blood-brain barrier (BBB)/blood-brain tumor barrier (BBTB) and GBM microenvironment. These factors limit the uptake of anti-cancer drugs by the tumor, thus limiting the therapeutic options. Current breakthroughs in nanotechnology provide new prospects concerning unconventional drug delivery approaches for GBM treatment. Specifically, swimming nanorobots show great potential in active targeted delivery, owing to their autonomous propulsion and improved navigation capacities across biological barriers, which further facilitate the development of GBM-targeted strategies. This review presents an overview of technological progress in different drug administration methods for GBM. Additionally, the limitations in clinical translation and future research prospects in this field are also discussed. This review aims to provide a comprehensive guideline for researchers and offer perspectives on further development of new drug delivery therapies to combat GBM.

Millimeter-scale magnetic implants paired with a fully integrated wearable device for wireless biophysical and biochemical sensing

Implantable sensors can directly interface with various organs for precise evaluation of health status. However, extracting signals from such sensors mainly requires transcutaneous wires, integrated circuit chips, or cumbersome readout equipment, which increases the risks of infection, reduces biocompatibility, or limits portability. Here, we develop a set of millimeter-scale, chip-less, and battery-less magnetic implants paired with a fully integrated wearable device for measuring biophysical and biochemical signals. The wearable device can induce a large amplitude damped vibration of the magnetic implants and capture their subsequent motions wirelessly. These motions reflect the biophysical conditions surrounding the implants and the concentration of a specific biochemical depending on the surface modification. Experiments in rat models demonstrate the capabilities of measuring cerebrospinal fluid (CSF) viscosity, intracranial pressure, and CSF glucose levels. This miniaturized system opens the possibility for continuous, wireless monitoring of a wide range of biophysical and biochemical conditions within the living organism.

Advancements in materials, manufacturing, propulsion and localization: propelling soft robotics for medical applications

Soft robotics is an emerging field showing immense potential for biomedical applications. This review summarizes recent advancements in soft robotics for in vitro and in vivo medical contexts. Their inherent flexibility, adaptability, and biocompatibility enable diverse capabilities from surgical assistance to minimally invasive diagnosis and therapy. Intelligent stimuli-responsive materials and bioinspired designs are enhancing functionality while improving biocompatibility. Additive manufacturing techniques facilitate rapid prototyping and customization. Untethered chemical, biological, and wireless propulsion methods are overcoming previous constraints to access new sites. Meanwhile, advances in tracking modalities like computed tomography, fluorescence and ultrasound imaging enable precision localization and control enable in vivo applications. While still maturing, soft robotics promises more intelligent, less invasive technologies to improve patient care. Continuing research into biocompatibility, power supplies, biomimetics, and seamless localization will help translate soft robots into widespread clinical practice.

Medicarpin suppresses proliferation and triggeres apoptosis by upregulation of BID, BAX, CASP3, CASP8, and CYCS in glioblastoma

Glioblastoma (GBM) is the most malignant brain tumor and incurable. Medicarpin (MED), a flavonoid compound from the legume family, has multiple targets and anticancer properties. However, the role of MED in GBM remains unclear. The objective of this study was to explore the effects of MED on the apoptosis of GBM and to explain the potential molecular mechanisms. We found that the IC50 values of U251 and U-87 MG cells treated with MED for 24 h were 271 μg/mL and 175 μg/mL, and the IC50 values for 48 h were 154 μg/mL and 161 μg/mL, respectively. Additionally, the cell cycle of U251 and U-87 MG cells were arrested at the G2/M phase. Furthermore, the apoptosis rate of U251 and U-87 MG cells increased from 6.26% to 18.36% and 12.46% to 31.33% for 48 h, respectively. The migration rate of U251 and U-87 MG decreased from 20% to 5% and 25% to 15% for 12 h and these of U251 and U-87 MG decreased from 50% to 28% and 60% to 25% for 24 h. MED suppressed GBM tumorigenesis, and improved survival rate of tumor-bearing mice. Taken together, MED triggered GBM apoptosis through upregulation of pro-apoptotic proteins (BID, BAX, CASP3, CASP8, and CYCS), showed strong inhibitory effects on cell proliferation and cell migration, and displayed anti-tumor activity in nude mice.