Tiny 2D silicon quantum sheets: a brain photonic nanoagent for orthotopic glioma theranostics

Neurophotonics: a comprehensive review, current challenges and future trends

The human brain, with its vast network of billions of neurons and trillions of synapses (connections) between diverse cell types, remains one of the greatest mysteries in science and medicine. Despite extensive research, an understanding of the underlying mechanisms that drive normal behaviors and response to disease states is still limited. Advancement in the Neuroscience field and development of therapeutics for related pathologies requires innovative technologies that can provide a dynamic and systematic understanding of the interactions between neurons and neural circuits. In this work, we provide an up-to-date overview of the evolution of neurophotonic approaches in the last 10 years through a multi-source, literature analysis. From an initial corpus of 243 papers retrieved from Scopus, PubMed and WoS databases, we have followed the PRISMA approach to select 56 papers in the area. Following a full-text evaluation of these 56 scientific articles, six main areas of applied research were identified and discussed: (1) Advanced optogenetics, (2) Multimodal neural interfaces, (3) Innovative therapeutics, (4) Imaging devices and probes, (5) Remote operations, and (6) Microfluidic platforms. For each area, the main technologies selected are discussed according to the photonic principles applied, the neuroscience application evaluated and the more indicative results of efficiency and scientific potential. This detailed analysis is followed by an outlook of the main challenges tackled over the last 10 years in the Neurophotonics field, as well as the main technological advances regarding specificity, light delivery, multimodality, imaging, materials and system designs. We conclude with a discussion of considerable challenges for future innovation and translation in Neurophotonics, from light delivery within the brain to physical constraints and data management strategies.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Doxorubicin-Loaded Liposome with the Function of "Killing Two Birds with One Stone" against Glioma

The blood-brain barrier (BBB) continues to be one of the main clinical obstacles in the treatment of glioma. Current chemotherapies always bring many different side effects, some even permanent. To date, nanomaterial-based vehicles have shown great potential in treating glioma. Herein, we developed a dual targeting liposomal delivery vector loaded with the anticancer drug doxorubicin (DOX) to treat glioma. SS31, a small peptide, has shown dual targeting effects of penetrating the BBB and specifically targeting mitochondria. In this study, a new liposomal delivery system, LS-DOX, was prepared by modifying DOX-loaded liposomes with SS31 for the treatment of in situ glioma. The liposomes demonstrated a high drug encapsulation rate and drug-loading capacity, satisfactory biocompatibility, high glioma accumulation ability, and good stability in vitro. Experimental results showed that the liposomes could effectively cross the BBB and target gliomas, and mitochondria-targeting of SS31 enhances cell uptake. In addition, the liposomes showed a good therapeutic effect on nude mice with glioma in situ with no obvious toxicity and side effects. Therefore, the present research will provide a novel alternative and reference for the effective treatment of glioma.

Advances in the two-dimensional layer materials for cancer diagnosis and treatment: unique advantages beyond the microsphere

In recent years, two-dimensional (2D) layer materials have shown great potential in the field of cancer diagnosis and treatment due to their unique structural, electronic, and chemical properties. These non-spherical materials have attracted increasing attention around the world because of its widely used biological characteristics. The application of 2D layer materials like lamellar graphene, transition metal dichalcogenides (TMDs), and black phosphorus (BPs) and so on have been developed for CT/MRI imaging, serum biosensing, drug targeting delivery, photothermal therapy, and photodynamic therapy. These unique applications for tumor are due to the multi-variable synthesis of 2D materials and the structural characteristics of good ductility different from microsphere. Based on the above considerations, the application of 2D materials in cancer is mainly carried out in the following three aspects: 1) In terms of accurate and rapid screening of tumor patients, we will focus on the enrichment of serum markers and sensitive signal transformation of 2D materials; 2) The progress of 2D nanomaterials in tumor MRI and CT imaging was described by comparing the performance of traditional contrast agents; 3) In the most important aspect, we will focus on the progress of 2D materials in the field of precision drug delivery and collaborative therapy, such as photothermal ablation, sonodynamic therapy, chemokinetic therapy, etc. In summary, this review provides a comprehensive overview of the advances in the application of 2D layer materials for tumor diagnosis and treatment, and emphasizes the performance difference between 2D materials and other types of nanoparticles (mainly spherical). With further research and development, these multifunctional layer materials hold great promise in the prospects, and challenges of 2D materials development are discussed.

Biomedical application of 2D nanomaterials in neuroscience

Two-dimensional (2D) nanomaterials, such as graphene, black phosphorus and transition metal dichalcogenides, have attracted increasing attention in biology and biomedicine. Their high mechanical stiffness, excellent electrical conductivity, optical transparency, and biocompatibility have led to rapid advances. Neuroscience is a complex field with many challenges, such as nervous system is difficult to repair and regenerate, as well as the early diagnosis and treatment of neurological diseases are also challenged. This review mainly focuses on the application of 2D nanomaterials in neuroscience. Firstly, we introduced various types of 2D nanomaterials. Secondly, due to the repairment and regeneration of nerve is an important problem in the field of neuroscience, we summarized the studies of 2D nanomaterials applied in neural repairment and regeneration based on their unique physicochemical properties and excellent biocompatibility. We also discussed the potential of 2D nanomaterial-based synaptic devices to mimic connections among neurons in the human brain due to their low-power switching capabilities and high mobility of charge carriers. In addition, we also reviewed the potential clinical application of various 2D nanomaterials in diagnosing and treating neurodegenerative diseases, neurological system disorders, as well as glioma. Finally, we discussed the challenge and future directions of 2D nanomaterials in neuroscience.

Photothermal and natural activity-based synergistic antibacterial effects of Ti3C2Tx MXene-loaded chitosan hydrogel against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) has strong resistance to antibiotic therapy. In this regard, developing antibiotic-free antibacterial agents is of great significance to treat MRSA infections. Herein, we loaded Ti₃C₂T_x MXene nanomaterial in the non-crosslinked chitosan (CS) hydrogel. The obtained MX-CS hydrogel is expected to not only adsorb MRSA cells via CS-MRSA interactions, but also gather the MXene-induced photothermal hyperthermia, achieving the efficient and intensive anti-MRSA photothermal therapy. As a result, under NIR irradiation (808 nm, 1.6 W/cm², 5 min), MX-CS showed a greater photothermal effect than MXene alone did (30 μg/mL, 49.9 °C for MX-CS and 46.5 °C for MXene). Importantly, MRSA cells were rapidly adsorbed on MX-CS hydrogel (containing 30 μg/mL MXene) and completely inhibited (99.18 %) under NIR irradiation for 5 min. In contrast, MXene (30 μg/mL) and CS hydrogel alone only inhibited 64.52 % and 23.72 % MRSA, respectively, significantly lower than the inhibition caused by MX-CS (P < 0.001). Interestingly, when the hyperthermia was depleted by a 37 °C water bath, the bacterial inhibition rate of MX-CS significantly decreased to 24.65 %. In conclusion, MX-CS hydrogel has a remarkable synergistic anti-MRSA activity by gathering MRSA cells and MXene-induced hyperthermia, and may have great potentials in treating MRSA-infected diseases.

Glioma diagnosis and therapy: Current challenges and nanomaterial-based solutions

Glioma is often referred to as one of the most dreadful central nervous system (CNS)-specific tumors with rapidly-proliferating cancerous glial cells, accounting for nearly half of the brain tumors at an annual incidence rate of 30-80 per a million population. Although glioma treatment remains a significant challenge for researchers and clinicians, the rapid development of nanomedicine provides tremendous opportunities for long-term glioma therapy. However, several obstacles impede the development of novel therapeutics, such as the very tight blood-brain barrier (BBB), undesirable hypoxia, and complex tumor microenvironment (TME). Several efforts have been dedicated to exploring various nanoformulations for improving BBB permeation and precise tumor ablation to address these challenges. Initially, this article briefly introduces glioma classification and various pathogenic factors. Further, currently available therapeutic approaches are illustrated in detail, including traditional chemotherapy, radiotherapy, and surgical practices. Then, different innovative treatment strategies, such as tumor-treating fields, gene therapy, immunotherapy, and phototherapy, are emphasized. In conclusion, we summarize the article with interesting perspectives, providing suggestions for future glioma diagnosis and therapy improvement.

NIR-II fluorescence visualization of ultrasound-induced blood-brain barrier opening for enhanced photothermal therapy against glioblastoma using indocyanine green microbubbles

Focused ultrasound (FUS)-induced blood-brain barrier (BBB) opening is crucial for enhancing glioblastoma (GBM) therapies. However, an in vivo imaging approach with a high spatial-temporal resolution to monitor the BBB opening process in situ and synchronously is still lacking. Herein, we report the use of indocyanine green (ICG)-dopped microbubbles (MBs-ICG) for visualizing the FUS-induced BBB opening and enhancing the photothermal therapy (PTT) against GBM. The MBs-ICG show bright fluorescence in the second near-infrared window (NIR-II), ultrasound contrast, and ultrasound-induced size transformation properties. By virtue of complementary contrast properties, MBs-ICG can be successfully applied for cerebral vascular imaging with NIR-II fluorescence resolution of ∼168.9 μm and ultrasound penetration depth of ∼7 mm. We further demonstrate that MBs-ICG can be combined with FUS for in situ and synchronous visualization of the BBB opening with a NIR-II fluorescence signal-to-background ratio of 6.2 ± 1.2. Finally, our data show that the MBs-ICG transform into lipid-ICG nanoparticles under FUS irradiation, which then rapidly penetrate the tumor tissues within 10 min and enhance PTT in orthotopic GBM-bearing mice. The multifunctional MBs-ICG approach provides a novel paradigm for monitoring BBB opening and enhancing GBM therapy.

Multifunctional nanotheranostics for near infrared optical imaging-guided treatment of brain tumors

Malignant brain tumors, a heterogeneous group of primary and metastatic neoplasms in the central nervous system (CNS), are notorious for their highly invasive and devastating characteristics, dismal prognosis and low survival rate. Recently, near-infrared (NIR) optical imaging modalities including fluorescence imaging (FLI) and photoacoustic imaging (PAI) have displayed bright prospect in innovation of brain tumor diagnoses, due to their merits, like noninvasiveness, high spatiotemporal resolution, good sensitivity and large penetration depth. Importantly, these imaging techniques have been widely used to vividly guide diverse brain tumor therapies in a real-time manner with high accuracy and efficiency. Herein, we provide a systematic summary of the state-of-the-art NIR contrast agents (CAs) for brain tumors single-modal imaging (e.g., FLI and PAI), dual-modal imaging (e.g., FLI/PAI, FLI/magnetic resonance imaging (MRI) and PAI/MRI) and triple-modal imaging (e.g., MRI/FLI/PAI and MRI/PAI/computed tomography (CT) imaging). In addition, we update the most recent progress on the NIR optical imaging-guided therapies, like single-modal (e.g., photothermal therapy (PTT), chemotherapy, surgery, photodynamic therapy (PDT), gene therapy and gas therapy), dual-modal (e.g., PTT/chemotherapy, PTT/surgery, PTT/PDT, PDT/chemotherapy, PTT/chemodynamic therapy (CDT) and PTT/gene therapy) and triple-modal (e.g., PTT/PDT/chemotherapy, PTT/PDT/surgery, PTT/PDT/gene therapy and PTT/gene/chemotherapy). Finally, we discuss the opportunities and challenges of the CAs and nanotheranostics for future clinic translation.

Supramolecular engineering of cell membrane vesicles for cancer immunotherapy

The clinical translation of nanomedicines has been strongly hampered by the limitations of delivery vehicles, promoting scientists to search for novel nanocarriers. Although cell membrane-based delivery systems have attracted extensive attention, further functionalizations are urgently desired to augment their theranostic functions. We propose a cell-friendly supramolecular strategy to engineer cell membranes utilizing cyclodextrin-based host-guest molecular recognitions to fix the defects arising from chemical and genetic modifications. In this study, the supramolecular cell membrane vesicles (SCMVs) specifically accumulate in tumors, benefiting from tumor-homing capability and the enhanced permeability and retention effect. SCMVs co-delivering indocyanine green and an indoleamine 2,3-dioxygenase inhibitor effectively ablate tumors combining photodynamic therapy and immunotherapy. Driven by host-guest inclusion complexation, SCMVs successfully encapsulate resiquimod to repolarize tumor-associated macrophages into M1 phenotype, synergizing with immune checkpoint blockade therapy. This supramolecular engineering methodology based on noncovalent interactions presents a generalizable and cell-friendly tactic to develop living cell-originated nanomaterials for precise cancer therapy.

Nontoxic silicene photothermal agents with high near-infrared absorption for disassembly of Alzheimer's amyloid‑β fibrils

The disassembly and eliminating the amyloid-β (Aβ) aggregates has become an effective way to treat Alzheimer's disease (AD). Herein, for the first time, the near-infrared (NIR) activated silicene nanosheets (SNSs) have been identified as an effective nontoxic photothermal conversion agent for irreversibly disassembly of the Aβ_33-42 aggregates. The SNSs synthesized by a combination of mild oxidation method and liquid exfoliation method possess good biocompatibility and biodegradability, and high near-infrared photothermal conversion capabilities. Under NIR light, the SNSs could disassemble the large and dense Aβ_33-42 mature fibrils into short fibrils and even form thin films, leading to the degradation rate of 96.47%. The circular dichroism spectrum, fluorescent spectra, and nanostructure were analyzed to monitor the photothermal degradation of mature Aβ_33-42 fibrils for elaborating the mechanism beneath. This study might provide a clue for developing potential therapeutic strategy for AD and related neurodegenerative diseases.

Two-Dimensional Silicene/Silicon Nanosheets: An Emerging Silicon-Composed Nanostructure in Biomedicine

Silicon-composed nanomedicines are one of the most representative inorganic nanosystems in theranostic biomedicine. The emerging of new family members of silicon-composed nanosystems substantially contributes to their further clinical translation. 2D silicene/silicon nanosheets have recently been developed as an emerging topology of silicon-composed nanoparticles, which features unique planar nanostructure with large surface area, abundant surface chemistry, specific physiochemical property, and desirable biological effects. This progress report highlights and discusses the state-of-art developments of the elaborate construction of 2D silicene/silicon nanosheets for versatile biomedical applications, including top-down fabrication, multifunctionalization, surface engineering, and their available biomedical applications in tumor theranostics (e.g., bioimaging, photothermal ablation, chemotherapy, chemoreactive nanotherapy, radiotherapy, and synergistic nanotherapy) and antibacteria. Their large surface area originating from 2D nanostructure not only enables efficient loading and delivery of chemotherapeutic drugs, but also guarantees the multifunctionalization. Especially, 2D silicene/silicon nanosheets harness desirable photothermal-conversion performance for photonic hyperthermia and photoacoustic imaging in the near infrared biowindow, accompanied with the desirable biodegradability and biocompatibility, which is typically not possessed in other silicon-composed counterparts. The multivariate analysis on the facing challenges and future developments of these 2D silicene/silicon nanosheets have also been conducted and outlooked for further underpinning their clinical translations.

Intravital Whole-Process Monitoring Thermo-Chemotherapy Via 2D Silicon Nanoplatform: A Macro Guidance and Long-Term Microscopic Precise Imaging Strategy

Tumor angiogenesis is a complex process that is unamenable to intravital whole-process monitoring, especially on microscopic assessment of tumor microvessel and quantifying microvascular hemodynamics before and after the nanotherapeutics, which hinder the understanding of nanotheranostics outcomes in tumor treatment. Herein, a new photoacoustic (PA) imaging-optical coherence tomography angiography (OCTA)-laser speckle (LS) multimodal imaging strategy is first proposed, which is not only able to precisely macro guide the thermo-chemotherapy of tumor by monitoring blood oxygen saturation (SaO2 ) and hemoglobin content (HbT), but also capable of long-term microscopic investigating the microvessel morphology (microvascular density) and hemodynamics changes (relative blood flow) before and after the nanotherapeutics in vivo. Moreover, to realize the tumor thermo-chemotherapy treatment based on this novel multimodal imaging strategy, a 2D 5-fluorouracil silicon nanosheets (5-Fu-Si NSs) therapeutic agent is designed. Furthermore, 2D high-resolution tumor microvascular images in different stage display that tendency of the thermo-chemotherapy effect is closely associated with tumor angiogenesis. Taken together, the investigations establish the fundamental base in theory and technology for further tailoring the novel specific diagnosis and treatment strategy in tumor. More importantly, this technique will be beneficial to evaluate the tumor microvascular response to nanotherapeutics at microscale.

Cryogenic Exfoliation of 2D Stanene Nanosheets for Cancer Theranostics

Stanene (Sn)-based materials have been extensively applied in industrial production and daily life, but their potential biomedical application remains largely unexplored, which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials. Herein, we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional (2D) Sn nanosheets (SnNSs). The obtained SnNSs exhibited a typical sheet-like structure with an average size of ~ 100 nm and a thickness of ~ 5.1 nm. After PEGylation, the resulting PEGylated SnNSs (SnNSs@PEG) exhibited good stability, superior biocompatibility, and excellent photothermal performance, which could serve as robust photothermal agents for multi-modal imaging (fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer. Furthermore, we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs, revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal. This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics. This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications.

Nanomaterials for Diagnosis and Treatment of Brain Cancer: Recent Updates

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