Liquid metal based theranostic nanoplatforms: Application in cancer therapy, imaging and biosensing

Electrochemically-driven actuators: from materials to mechanisms and from performance to applications

Soft actuators, pivotal for converting external energy into mechanical motion, have become increasingly vital in a wide range of applications, from the subtle engineering of soft robotics to the demanding environments of aerospace exploration. Among these, electrochemically-driven actuators (EC actuators), are particularly distinguished by their operation through ion diffusion or intercalation-induced volume changes. These actuators feature notable advantages, including precise deformation control under electrical stimuli, freedom from Carnot efficiency limitations, and the ability to maintain their actuated state with minimal energy use, akin to the latching state in skeletal muscles. This review extensively examines EC actuators, emphasizing their classification based on diverse material types, driving mechanisms, actuator configurations, and potential applications. It aims to illuminate the complicated driving mechanisms of different categories, uncover their underlying connections, and reveal the interdependencies among materials, mechanisms, and performances. We conduct an in-depth analysis of both conventional and emerging EC actuator materials, casting a forward-looking lens on their trajectories and pinpointing areas ready for innovation and performance enhancement strategies. We also navigate through the challenges and opportunities within the field, including optimizing current materials, exploring new materials, and scaling up production processes. Overall, this review aims to provide a scientifically robust narrative that captures the current state of EC actuators and sets a trajectory for future innovation in this rapidly advancing field.

Smart Eutectic Gallium-Indium: From Properties to Applications

Eutectic gallium-indium (EGaIn), a liquid metal with a melting point close to or below room temperature, has attracted extensive attention in recent years due to its excellent properties such as fluidity, high conductivity, thermal conductivity, stretchability, self-healing capability, biocompatibility, and recyclability. These features of EGaIn can be adjusted by changing the experimental condition, and various composite materials with extended properties can be further obtained by mixing EGaIn with other materials. In this review, not only the are unique properties of EGaIn introduced, but also the working principles for the EGaIn-based devices are illustrated and the developments of EGaIn-related techniques are summarized. The applications of EGaIn in various fields, such as flexible electronics (sensors, antennas, electronic circuits), molecular electronics (molecular memory, opto-electronic switches, or reconfigurable junctions), energy catalysis (heat management, motors, generators, batteries), biomedical science (drug delivery, tumor therapy, bioimaging and neural interfaces) are reviewed. Finally, a critical discussion of the main challenges for the development of EGaIn-based techniques are discussed, and the potential applications in new fields are prospected.

2D Hetero-Nanoconstructs of Black Phosphorus for Breast Cancer Theragnosis: Technological Advancements

As per global cancer statistics of 2020, female breast cancer is the most commonly diagnosed cancer and also the foremost cause of cancer death in women. Traditional treatments include a number of negative effects, making it necessary to investigate novel smart drug delivery methods and identify new therapeutic approaches. Efforts for developing novel strategies for breast cancer therapy are being devised worldwide by various research groups. Currently, two-dimensional black phosphorus nanosheets (BPNSs) have attracted considerable attention and are best suited for theranostic nanomedicine. Particularly, their characteristics, including drug loading efficacy, biocompatibility, optical, thermal, electrical, and phototherapeutic characteristics, support their growing demand as a potential substitute for graphene-based nanomaterials in biomedical applications. In this review, we have explained different platforms of BP nanomaterials for breast cancer management, their structures, functionalization approaches, and general methods of synthesis. Various characteristics of BP nanomaterials that make them suitable for cancer therapy and diagnosis, such as large surface area, nontoxicity, solubility, biodegradability, and excellent near-infrared (NIR) absorption capability, are discussed in the later sections. Next, we summarize targeting approaches using various strategies for effective therapy with BP nanoplatforms. Then, we describe applications of BP nanomaterials for breast cancer treatment, which include drug delivery, codelivery of drugs, photodynamic therapy, photothermal therapy, combined therapy, gene therapy, immunotherapy, and multidrug resistance reversal strategy. Finally, the present challenges and future aspects of BP nanomaterials are discussed.

Emerging Liquid Metal Biomaterials: From Design to Application

Liquid metals (LMs) as emerging biomaterials possess unique advantages including their favorable biosafety, high fluidity, and excellent electrical and thermal conductivities, thus providing a unique platform for a wide range of biomedical applications ranging from drug delivery, tumor therapy, and bioimaging to biosensors. The structural design and functionalization of LMs endow them with enhanced functions such as enhanced targeting ability and stimuli responsiveness, enabling them to achieve better and even multifunctional synergistic therapeutic effects. Herein, the advantages of LMs in biomedicine are presented. The design of LM-based biomaterials with different scales ranging from micro-/nanoscale to macroscale and various components is explored in-depth to promote the understanding of structure-property relationships, guiding their performance optimization and applications. Furthermore, the related advanced progress in the development of LM-based biomaterials in biomedicine is summarized. Current challenges and prospects of LMs in the biomedical field are also discussed.

Regulation of Sirtuin-3 and ERK1/2/p38MAPK by the combination Ga nanoparticles/γ-radiation low dosage: an effective approach for treatment of hepatocellular carcinoma

Background

Synthesized gallium nanoparticles synthesized by grape seed extract were characterized with spherical shape and size range less than100 nm, possessing the functional groups of the biological material. The purpose of this study is to evaluate gallium nanoparticles synthesized by grape seed extract, as an antitumor agent with low dose of γ-radiation against hepatocellular carcinoma in rats.

Aim of work

This work aimed to evaluate the antitumor effect of gallium nanoparticles synthesized (GaNPs) by grape seed extract and the co-binded treatment with low dose of γ-radiation on hepatocellular carcinoma in rats, through evaluating their effect on signaling pathways and tumor markers.

Results

Cytotoxic activity of GaNPs synthesized by grape seed extract was estimated by mediated cytotoxicity assay on HepG2 cell line that recorded IC₅₀ of 388.8 μg/ml. To achieve these goals, eighty Wistar male rats (120−150 g) will be divided into eight groups, each of 10 rats. The animals are administered with diethylnitrosamine to induce hepatocellular carcinoma and then orally administered with GaNPs synthesized by grape seed extract (38.5 mg/kg) in combination with the exposure of the total body to a low dose of γ-radiation (0.5 Gy). The treatment modulated plasma vascular endothelial growth factor and alpha-fetoprotein. In addition, the immunoblotting results of nuclear factor-kappa beta showed a marked downregulation of extracellular signal-regulated kinase, mitogen-activated protein kinase, and c-Jun NH2-terminal kinase alongside, significantly elevating the level of Sirtuin-3 and caspase-3.

Conclusions

It can be concluded that the combined treatment with GaNPs synthesized by grape seed extract and low dose γ-radiation may have antineoplastic activity against hepatocarcinogenesis by inhibiting signal pathways extracellular signal-regulated kinase/mitogen-activated protein kinase/c-Jun NH2-terminal kinase and stimulating apoptotic protein.

Liquid metal biomaterials for biomedical imaging

Liquid metals (LMs) not only retain the basic properties of metallic biomaterials, such as high thermal conductivity and high electrical conductivity, but also possess flexibility, flowability, deformability, plasticity, good adhesion, and so on. Therefore, they open many possibilities of extending soft metals into biomedical sciences including biomedical imaging. One of the special properties of LMs is that they can provide a controllable material system in which the electrical, thermal, mechanical, and chemical properties can be controlled on a large scale. This paper reviews the preparation and characteristics of LM-based biomaterials classified into four categories: LM micro/nanoparticles, surface modified LM droplets, LM composites with inorganic substances, and LM composites with organic polymers. Besides, considering the most important requirement for biomaterials is biocompatibility, the paper also analyzes the toxicity results of various LM biomaterials when used in the biomedical area, from different levels including body weight measurement, histology evaluation, and blood biochemistry tests. Next, the applications of LMs in X-ray, CT, MRI, photoacoustic imaging, and molecular imaging are introduced in detail. And finally, the challenges and opportunities of their application in medical imaging are also discussed.

Liquid metal polymer composite: Flexible, conductive, biocompatible, and antimicrobial scaffold

Gallium and its alloys, such as eutectic gallium indium alloy (EGaIn), a form of liquid metal, have recently attracted the attention of researchers due to their low toxicity and electrical and thermal conductivity for biomedical application. However, further research is required to harness EGaIn-composites advantages and address their application as a biomedical scaffold. In this research, EGaIn-polylactic acid/polycaprolactone composites with and without a second conductive filler, MXene, were prepared and characterized. The addition of MXene, into the EGaIn-composite, can improve the composite's electrochemical properties by connecting the liquid metal droplets resulting in electrically conductive continuous pathways within the polymeric matrix. The results showed that the composite with 50% EGaIn and 4% MXene, displayed optimal electrochemical properties and enhanced mechanical and radiopacity properties. Furthermore, the composite showed good biocompatibility, examined through interactions with fibroblast cells, and antibacterial properties against methicillin-resistant Staphylococcus aureus. Therefore, the liquid metal (EGaIn) polymer composite with MXene provides a first proof-of-concept engineering scaffold strategy with low toxicity, functional electrochemical properties, and promising antimicrobial properties.

Progress of Phototherapy Applications in the Treatment of Bone Cancer

Bone cancer including primary bone cancer and metastatic bone cancer, remains a challenge claiming millions of lives and affecting the life quality of survivors. Conventional treatments of bone cancer include wide surgical resection, radiotherapy, and chemotherapy. However, some bone cancer cells may remain or recur in the local area after resection, some are highly resistant to chemotherapy, and some are insensitive to radiotherapy. Phototherapy (PT) including photodynamic therapy (PDT) and photothermal therapy (PTT), is a clinically approved, minimally invasive, and highly selective treatment, and has been widely reported for cancer therapy. Under the irradiation of light of a specific wavelength, the photosensitizer (PS) in PDT can cause the increase of intracellular ROS and the photothermal agent (PTA) in PTT can induce photothermal conversion, leading to the tumoricidal effects. In this review, the progress of PT applications in the treatment of bone cancer has been outlined and summarized, and some envisioned challenges and future perspectives have been mentioned. This review provides the current state of the art regarding PDT and PTT in bone cancer and inspiration for future studies on PT.

Liquid Metal-Based Soft Electronics for Wearable Healthcare

Wearable healthcare devices have garnered substantial interest for the realization of personal health management by monitoring the physiological parameters of individuals. Attaining the integrity between the devices and the biological interfaces is one of the greatest challenges to achieving high-quality body information in dynamic conditions. Liquid metals, which exist in the liquid phase at room temperatures, are advanced intensively as conductors for deformable devices because of their excellent stretchability and self-healing ability. The unique surface chemistry of liquid metals allows the development of various sensors and devices in wearable form. Also, the biocompatibility of liquid metals, which is verified through numerous biomedical applications, holds immense potential in uses on the surface and inside of a living body. Here, the recent progress of liquid metal-based wearable electronic devices for healthcare with respect to the featured properties and the processing technologies is discussed. Representative examples of applications such as biosensors, neural interfaces, and a soft interconnection for devices are reviewed. The current challenges and prospects for further development are also discussed, and the future directions of advances in the latest research are explored.

Enzyme-Powered Liquid Metal Nanobots Endowed with Multiple Biomedical Functions

Catalytically powered micro/nanobots (MNBs) can perform active movement by harnessing energy from in situ chemical reactions and show tremendous potential in biomedical applications. However, the development of imageable MNBs that are driven by bioavailable fuels and possess multiple therapeutic functions remains challenging. To resolve such issues, we herein propose enzyme (urease) powered liquid metal (LM) nanobots that are naturally of multiple therapeutic functions and imaging signals. The main body of the nanobot is composed of a biocompatible LM nanoparticle encapsulated by polydopamine (PDA). Urease enzyme needed for the powering and desired drug molecules, e.g., cefixime trihydrate antibiotic, are grafted on external surfaces of the PDA shell. Such a chemical composition endows the nanobots with dual-mode ultrasonic (US) and photoacoustic (PA) imaging signals and favorable photothermal effect. These LM nanobots exhibit positive chemotaxis and therefore can be collectively guided along a concentration gradient of urea for targeted transportation. When exposed to NIR light, the LM nanobots would deform and complete the function change from active drug carriers to photothermal reagents, to achieve synergetic antibacterial treatment by both photothermal and chemotherapeutic effects. The US and PA properties of the LM nanoparticle can be used to not only track and monitor the active movement of the nanobots in a microfluidic vessel model but also visualize their dynamics in the bladder of a living mouse in vivo. To conclude, the LM nanobots demonstrated herein represent a proof-of-concept therapeutic nanosystem with multiple biomedical functionalities, providing a feasible tool for preclinical studies and clinical trials of MNB-based imaging-guided therapy.

Transient and Efficient Vascular Permeability Window for Adjuvant Drug Delivery Triggered by Microbeam Radiation

BACKGROUND

Microbeam Radiation Therapy (MRT) induces a transient vascular permeability window, which offers a novel drug-delivery system for the preferential accumulation of therapeutic compounds in tumors. MRT is a preclinical cancer treatment modality that spatially fractionates synchrotron X-rays into micrometer-wide planar microbeams which can induce transient vascular permeability, especially in the immature tumor vessels, without compromising vascular perfusion. Here, we characterized this phenomenon using Chicken Chorioallantoic Membrane (CAM) and demonstrated its therapeutic potential in human glioblastoma xenografts in mice.

METHODS

the developing CAM was exposed to planar-microbeams of 75 Gy peak dose with Synchrotron X-rays. Similarly, mice harboring human glioblastoma xenografts were exposed to peak microbeam doses of 150 Gy, followed by treatment with Cisplatin. Tumor progression was documented by Magnetic Resonance Imaging (MRI) and caliper measurements.

RESULTS

CAM exposed to MRT exhibited vascular permeability, beginning 15 min post-irradiation, reaching its peak from 45 min to 2 h, and ending by 4 h. We have deemed this period the "permeability window". Morphological analysis showed partially fragmented endothelial walls as the cause of the increased transport of FITC-Dextran into the surrounding tissue and the extravasation of 100 nm microspheres (representing the upper range of nanoparticles). In the human glioblastoma xenografts, MRI measurements showed that the combined treatment dramatically reduced the tumor size by 2.75-fold and 5.25-fold, respectively, compared to MRT or Cisplatin alone.

CONCLUSIONS

MRT provides a novel mechanism for drug delivery by increasing vascular transpermeability while preserving vessel integrity. This permeability window increases the therapeutic index of currently available chemotherapeutics and could be combined with other therapeutic agents such as Nanoparticles/Antibodies/etc.

Mini/Micro/Nano Scale Liquid Metal Motors

Swimming motors navigating in complex fluidic environments have received tremendous attention over the last decade. In particular, liquid metal (LM) as a new emerging material has shown considerable potential in furthering the development of swimming motors, due to their unique features such as fluidity, softness, reconfigurability, stimuli responsiveness, and good biocompatibility. LM motors can not only achieve directional motion but also deformation due to their liquid nature, thus providing new and unique capabilities to the field of swimming motors. This review aims to provide an overview of the recent advances of LM motors and compare the difference in LM macro and micromotors from fabrication, propulsion, and application. Here, LM motors below 1 cm, named mini/micro/nano scale liquid metal motors (MLMTs) will be discussed. This work will present physicochemical characteristics of LMs and summarize the state-of-the-art progress in MLMTs. Finally, future outlooks including both opportunities and challenges of mini/micro/nano scale liquid metal motors are also provided.

Galvanic replacement reaction for in situ fabrication of litchi-shaped heterogeneous liquid metal-Au nano-composite for radio-photothermal cancer therapy

With tremendous research advances in biomedical application, liquid metals (LM) also offer fantastic chemistry for synthesis of novel nano-composites. Herein, as a pioneering trial, litchi-shaped heterogeneous eutectic gallium indium-Au nanoparticles (EGaIn-Au NPs), served as effective radiosensitizer and photothermal agent for radio-photothermal cancer therapy, have been successfully prepared using in situ interfacial galvanic replacement reaction. The enhanced photothermal conversion efficiency and boosted radio-sensitization effect could be achieved with the reduction of Au nanodots onto the eutectic gallium indium (EGaIn) NPs surface. Most importantly, the growth of tumor could be effectively inhibited under the combined radio-photothermal therapy mediated by EGaIn-Au NPs. Inspired by this approach, in situ interfacial galvanic replacement reaction may open a novel strategy to fabricate LM-based nano-composite with advanced multi-functionalities.

Biomimetic nanoarchitecturing: A disguised attack on cancer cells

With the changing face of healthcare, there is a demand for drug delivery systems that have increased efficacy and biocompatibility. Nanotechnology derived drug carrier systems were found to be ideal candidates to meet these demands. Among the vast number of nanosized delivery systems, biomimetic nanoparticles have been researched at length. These nanoparticles mimic cellular functions and are highly biocompatible. They are also able to avoid clearance by the reticuloendothelial system which increases the time spent by them in the systemic circulation. Additionally, their low immunogenicity and targeting ability increase their significance as drug carriers. Based on their core material we have summarized them as biomimetic inorganic nanoparticles, biomimetic polymeric nanoparticles, and biomimetic lipid nanoparticles. The core then may be coated using membranes derived from erythrocytes, cancer cells, leukocytes, stem cells, and other membranes to endow them with biomimetic properties. They can be used for personalized therapy and diagnosis of a large number of diseases, primarily cancer. This review summarizes the various therapeutic approaches using biomimetic nanoparticles along with their applications in the field of cancer imaging, nucleic acid therapy and theranostic properties. A brief overview about toxicity concerns related to these nanoconstructs has been added to provide knowledge about biocompatibility of such nanoparticles.