On-Demand Biodegradable Boron Nitride Nanoparticles for Treating Triple Negative Breast Cancer with Boron Neutron Capture Therapy

Boron Nitride Nanosheets Induce Lipid Accumulation and Autophagy in Human Alveolar Lung Epithelial Cells Cultivated at Air-Liquid Interface

Hexagonal boron nitride (hBN) is an emerging 2D material attracting significant attention due to its superior electrical, chemical, and therapeutic properties. However, inhalation toxicity mechanisms of hBN in human lung cells are poorly understood. Here, cellular interaction and effects of hBN nanosheets is investigated in alveolar epithelial cells cultured on porous inserts and exposed under air-liquid interface conditions for 24 h. hBN is taken up by the cells as determined in a label-free manner via RAMAN-confocal microscopy, ICP-MS, TEM, and SEM-EDX. No significant (p > 0.05) effects are observed on cell membrane integrity (LDH release), epithelial barrier integrity (TEER), interleukin-8 cytokine production or reactive oxygen production at tested dose ranges (1, 5, and 10 µg cm-2). However, it is observed that an enhanced accumulation of lipid granules in cells indicating the effect of hBN on lipid metabolism. In addition, it is observed that a significant (p < 0.05) and dose-dependent (5 and 10 µg cm-2) induction of autophagy in cells after exposure to hBN, potentially associated with the downstream processing and breakdown of excess lipid granules to maintain lipid homeostasis. Indeed, lysosomal co-localization of lipid granules supporting this argument is observed. Overall, the results suggest that the continuous presence of excess intracellular lipids may provoke adverse outcomes in the lungs.

Fluorinated BPA derivatives enhanced 10B delivery in tumors

Boron neutron capture therapy (BNCT) is an emerging approach for treating malignant tumors with binary targeting. However, its clinical application has been hampered by insufficient 10B accumulation in tumors and low 10B concentration ratios of tumor-to-blood (T/B) and tumor-to-normal tissue (T/N). Herein, we developed fluorinated BPA derivatives with different fluorine groups as boron delivery agents for enabling sufficient 10B accumulation in tumors and enhancing T/B and T/N ratios. Our findings demonstrated that fluorinated BPA derivatives had good biological safety. Furthermore, fluorinated BPA derivatives showed improved 10B accumulation in tumors and enhanced T/B and T/N ratios compared to the clinical boron drug fructose-BPA (f-BPA). In particular, in B16-F10 tumor-bearing mice, fluorinated BPA derivatives met the requirements for clinical BNCT even at half of the clinical dose. Thus, fluorinated BPA derivatives are potentially effective boron delivery agents for clinical BNCT in melanoma.

Molecular engineering of AIE-active boron clustoluminogens for enhanced boron neutron capture therapy

The development of boron delivery agents bearing an imaging capability is crucial for boron neutron capture therapy (BNCT), yet it has been rarely explored. Here we present a new type of boron delivery agent that integrates aggregation-induced emission (AIE)-active imaging and a carborane cluster for the first time. In doing so, the new boron delivery agents have been rationally designed by incorporating a high boron content unit of a carborane cluster, an erlotinib targeting unit towards lung cancer cells, and a donor-acceptor type AIE unit bearing naphthalimide. The new boron delivery agents demonstrate both excellent AIE properties for imaging purposes and highly selective accumulation in tumors. For example, at a boron delivery agent dose of 15 mg kg-1, the boron amount reaches over 20 μg g-1, and both tumor/blood (T/B) and tumor/normal cell (T/N) ratios reach 20-30 times higher than those required by BNCT. The neutron irradiation experiments demonstrate highly efficient tumor growth suppression without any observable physical tissue damage and abnormal behavior in vivo. This study not only expands the application scopes of both AIE-active molecules and boron clusters, but also provides a new molecular engineering strategy for a deep-penetrating cancer therapeutic protocol based on BNCT.

Protein-based bioactive coatings: from nanoarchitectonics to applications

Protein-based bioactive coatings have emerged as a versatile and promising strategy for enhancing the performance and biocompatibility of diverse biomedical materials and devices. Through surface modification, these coatings confer novel biofunctional attributes, rendering the material highly bioactive. Their widespread adoption across various domains in recent years underscores their importance. This review systematically elucidates the behavior of protein-based bioactive coatings in organisms and expounds on their underlying mechanisms. Furthermore, it highlights notable advancements in artificial synthesis methodologies and their functional applications in vitro. A focal point is the delineation of assembly strategies employed in crafting protein-based bioactive coatings, which provides a guide for their expansion and sustained implementation. Finally, the current trends, challenges, and future directions of protein-based bioactive coatings are discussed.

Laser-Synthesized Elemental Boron Nanoparticles for Efficient Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) is one of the most appealing radiotherapy modalities, whose localization can be further improved by the employment of boron-containing nanoformulations, but the fabrication of biologically friendly, water-dispersible nanoparticles (NPs) with high boron content and favorable physicochemical characteristics still presents a great challenge. Here, we explore the use of elemental boron (B) NPs (BNPs) fabricated using the methods of pulsed laser ablation in liquids as sensitizers of BNCT. Depending on the conditions of laser-ablative synthesis, the used NPs were amorphous (a-BNPs) or partially crystallized (pc-BNPs) with a mean size of 20 nm or 50 nm, respectively. Both types of BNPs were functionalized with polyethylene glycol polymer to improve colloidal stability and biocompatibility. The NPs did not initiate any toxicity effects up to concentrations of 500 µg/mL, based on the results of MTT and clonogenic assay tests. The cells with BNPs incubated at a 10B concentration of 40 µg/mL were then irradiated with a thermal neutron beam for 30 min. We found that the presence of BNPs led to a radical enhancement in cancer cell death, namely a drop in colony forming capacity of SW-620 cells down to 12.6% and 1.6% for a-BNPs and pc-BNPs, respectively, while the relevant colony-forming capacity for U87 cells dropped down to 17%. The effect of cell irradiation by neutron beam uniquely was negligible under these conditions. Finally, to estimate the dose and regimes of irradiation for future BNCT in vivo tests, we studied the biodistribution of boron under intratumoral administration of BNPs in immunodeficient SCID mice and recorded excellent retention of boron in tumors. The obtained data unambiguously evidenced the effect of a neutron therapy enhancement, which can be attributed to efficient BNP-mediated generation of α-particles.

In vivo investigation of boron-rich nanodrugs for treating triple-negative breast cancers via boron neutron capture therapy

Triple-negative breast cancer (TNBC) is characterized by highly proliferative cancer cells and is the only subtype of breast cancer that lacks a targeted therapy. Boron neutron capture therapy (BNCT) is an approach that combines chemotherapy with radiotherapy and can potentially offer beneficial targeted treatment for TNBC patients owing to its unique ability to eradicate cancer cells selectively while minimizing damage to the surrounding healthy cells. Since BNCT relies on specific delivery of a high loading of B10 to the tumor site, there is growing research interest to develop more potent boron-based drugs for BNCT that can overcome the limitations of small-molecule boron compounds. In this study, polyethylene-glycol-coated boron carbon oxynitride nanoparticles (PEG@BCNO) of size 134.2±23.6nm were prepared as a promising drug for BNCT owing to their high boron content and enhanced biocompatibility. The therapeutic efficiency of PEG@BCNO was compared with a state-of-the-art 10BPA boron drug in mice bearing MDA-MB-231 tumor. In the orthotopic mouse model, PEG@BCNO showed higher B10 accumulation in the tumor tissues (6 μg 10B/g tissue compared to 3 μg 10B/g tissue in mice administered B10-enriched 10BPA drug) despite using the naturally occurring 11B/10B boron precursor in the preparation of the BCNO nanoparticles. The in vivo biodistribution of PEG@BCNO in mice bearing MDA-MB-231 showed a tumor/blood ratio of ~3.5, which is comparable to that of the state-of-the-art 10BPA-fructose drug. We further demonstrated that upon neutron irradiation, the mice bearing MDA-MB-231 tumor cells treated with PEG@BCNO and 10BPA showed tumor growth delay times of 9 days and 1 day, respectively, compared to mice in the control group after BNCT. The doubling times (DTs) for mice treated with PEG@BCNO and 10BPA as well as mice in the control group were calculated to be 31.5, 19.8, and 17.7 days, respectively. Immunohistochemical staining for the p53 and caspase-3 antibodies revealed that mice treated with PEG@BCNO showed lower probability of cancer recurrence and greater level of cellular apoptosis than mice treated with 10BPA and mice in the control group. Our study thus demonstrates the potential of pegylated BCNO nanoparticles in effectively inhibiting the growth of TNBC tumors compared to the state-of-the-art boron drug 10BPA.

Bioorthogonal chemistry for prodrug activation in vivo

Prodrugs have emerged as a major strategy for addressing clinical challenges by improving drug pharmacokinetics, reducing toxicity, and enhancing treatment efficacy. The emergence of new bioorthogonal chemistry has greatly facilitated the development of prodrug strategies, enabling their activation through chemical and physical stimuli. This "on-demand" activation using bioorthogonal chemistry has revolutionized the research and development of prodrugs. Consequently, prodrug activation has garnered significant attention and emerged as an exciting field of translational research. This review summarizes the latest advancements in prodrug activation by utilizing bioorthogonal chemistry and mainly focuses on the activation of small-molecule prodrugs and antibody-drug conjugates. In addition, this review also discusses the opportunities and challenges of translating these advancements into clinical practice.

The Dawn of a New Era: Tumor-Targeting Boron Agents for Neutron Capture Therapy

Cancer is widely recognized as one of the most devastating diseases, necessitating the development of intelligent diagnostic techniques, targeted treatments, and early prognosis evaluation to ensure effective and personalized therapy. Conventional treatments, unfortunately, suffer from limitations and an increased risk of severe complications. In light of these challenges, boron neutron capture therapy (BNCT) has emerged as a promising approach for cancer treatment with unprecedented precision to selectively eliminate tumor cells. The distinctive and promising characteristics of BNCT hold the potential to revolutionize the field of oncology. However, the clinical application and advancement of BNCT technology face significant hindrance due to the inherent flaws and limited availability of current clinical drugs, which pose substantial obstacles to the practical implementation and continued progress of BNCT. Consequently, there is an urgent need to develop efficient boron agents with higher boron content and specific tumor-targeting properties. Researchers aim to address this need by integrating tumor-targeting strategies with BNCT, with the ultimate goal of establishing BNCT as an effective, readily available, and cutting-edge treatment modality for cancer. This review delves into the recent advancements in integrating tumor-targeting strategies with BNCT, focusing on the progress made in developing boron agents specifically designed for BNCT. By exploring the current state of BNCT and emphasizing the prospects of tumor-targeting boron agents, this review provides a comprehensive overview of the advancements in BNCT and highlights its potential as a transformative treatment option for cancer.

Next generation of boron neutron capture therapy (BNCT) agents for cancer treatment

Boron neutron capture therapy (BNCT) is one of the most promising treatments among neutron capture therapies due to its long-term clinical application and unequivocally obtained success during clinical trials. Boron drug and neutron play an equivalent crucial role in BNCT. Nevertheless, current clinically used l-boronophenylalanine (BPA) and sodium borocaptate (BSH) suffer from large uptake dose and low blood to tumor selectivity, and that initiated overwhelm screening of next generation of BNCT agents. Various boron agents, such as small molecules and macro/nano-vehicles, have been explored with better success. In this featured article, different types of agents are rationally analyzed and compared, and the feasible targets are shared to present a perspective view for the future of BNCT in cancer treatment. This review aims at summarizing the current knowledge of a variety of boron compounds, reported recently, for the application of BCNT.

Tumor Eradication by Boron Neutron Capture Therapy with 10 B-enriched Hexagonal Boron Nitride Nanoparticles Grafted with Poly(Glycerol)

Boron neutron capture therapy (BNCT) has emerged as a treatment modality with high precision and efficacy of intractable tumors. At the core of effective tumor BNCT are 10 B carriers with facile preparation as well as advantageous pharmacokinetic and therapeutic profiles. Herein, the design and preparation of sub-10 nm 10 B-enriched hexagonal boron nitride nanoparticles grafted with poly(glycerol) (h-10 BN-PG), and their application to cancer treatment by BNCT are reported. By virtue of their small particle size and outstanding stealth property, h-10 BN-PG nanoparticles accumulate efficiently in murine CT26 colon tumors with a high intratumor 10 B concentration of 8.8%ID g-1 or 102.1 µg g-1 at 12 h post-injection. Moreover, h-10 BN-PG nanoparticles penetrate into the inside of the tumor parenchyma and then are taken up by the tumor cells. BNCT comprising a single bolus injection of h-10 BN-PG nanoparticles and subsequent one-time neutron irradiation results in significant shrinkage of subcutaneous CT26 tumors. h-10 BN-PG-mediated BNCT not only causes direct DNA damage to the tumor cells, but also triggers pronounced inflammatory immune response in the tumor tissues, which contributes to long-lasting tumor suppression after the neutron irradiation. Thus, the h-10 BN-PG nanoparticles are promising BNCT agents to eradicate tumor through highly efficient 10 B accumulation.

A Review of Planned, Ongoing Clinical Studies and Recent Development of BNCT in Mainland of China

Boron neutron capture therapy (BNCT) is a promising cancer treatment modality that combines targeted boron agents and neutron irradiation to selectively destroy tumor cells. In mainland China, the clinical implementation of BNCT has made certain progress, primarily driven by the development of compact neutron source devices. The availability, ease of operation, and cost-effectiveness offered by these compact neutron sources make BNCT more accessible to cancer treatment centers. Two compact neutron sources, one being miniature reactor-based (IHNI-1) and the other one being accelerator-based (NeuPex), have entered the clinical research phase and are planned for medical device registration. Moreover, several accelerator-based neutron source devices employing different technical routes are currently under construction, further expanding the options for BNCT implementation. In addition, the development of compact neutron sources serves as an experimental platform for advancing the development of new boron agents. Several research teams are actively involved in the development of boron agents. Various types of third-generation boron agents have been tested and studied in vitro and in vivo. Compared to other radiotherapy therapies, BNCT in mainland China still faces specific challenges due to its limited clinical trial data and its technical support in a wide range of professional fields. To facilitate the widespread adoption of BNCT, it is crucial to establish relevant technical standards for neutron devices, boron agents, and treatment protocols.

Next-Generation Boron Drugs and Rational Translational Studies Driving the Revival of BNCT

BNCT is a high-linear-energy transfer therapy that facilitates tumor-directed radiation delivery while largely sparing adjacent normal tissues through the biological targeting of boron compounds to tumor cells. Tumor-specific accumulation of boron with limited accretion in normal cells is the crux of successful BNCT delivery. Given this, developing novel boronated compounds with high selectivity, ease of delivery, and large boron payloads remains an area of active investigation. Furthermore, there is growing interest in exploring the immunogenic potential of BNCT. In this review, we discuss the basic radiobiological and physical aspects of BNCT, traditional and next-generation boron compounds, as well as translational studies exploring the clinical applicability of BNCT. Additionally, we delve into the immunomodulatory potential of BNCT in the era of novel boron agents and examine innovative avenues for exploiting the immunogenicity of BNCT to improve outcomes in difficult-to-treat malignancies.

Acute and Subacute Toxicity Evaluation of Erythrocyte Membrane-Coated Boron Nitride Nanoparticles

Boron nitride nanoparticles have been reported for boron drug delivery. However, its toxicity has not been systematically elucidated. It is necessary to clarify their potential toxicity profile after administration for clinical application. Here, we prepared erythrocyte membrane-coated boron nitride nanoparticles (BN@RBCM). We expect to use them for boron neutron capture therapy (BNCT) in tumors. In this study, we evaluated the acute toxicity and subacute toxicity of BN@RBCM of about 100 nm and determined the half-lethal dose (LD50) of the particles for mice. The results showed that the LD50 of BN@RBCM was 258.94 mg/kg. No remarkable pathological changes by microscopic observation were observed in the treated animals throughout the study period. These results indicate that BN@RBCM has low toxicity and good biocompatibility, which have great potential for biomedical applications.

Potential and Progress of 2D Materials in Photomedicine for Cancer Treatment

Over the last decades, photomedicine has made a significant impact and progress in treating superficial cancer. With tremendous efforts many of the technologies have entered clinical trials. Photothermal agents (PTAs) have been considered as emerging candidates for accelerating the outcome from photomedicine based cancer treatment. Besides various inorganic and organic candidates, 2D materials such as graphene, boron nitride, and molybdenum disulfide have shown significant potential for photothermal therapy (PTT). The properties such as high surface area to volume, biocompatibility, stability in physiological media, ease of synthesis and functionalization, and high photothermal conversion efficiency have made 2D nanomaterials wonderful candidates for PTT to treat cancer. The targeting or localized activation could be achieved when PTT is combined with chemotherapies, immunotherapies, or photodynamic therapy (PDT) to provide better outcomes with fewer side effects. Though significant development has been made in the field of phototherapeutic drugs, several challenges have restricted the use of PTT in clinical use and hence they have not yet been tested in large clinical trials. In this review, we attempted to discuss the progress, properties, applications, and challenges of 2D materials in the field of PTT and their application in photomedicine.

Study of Lithium Biodistribution and Nephrotoxicity in Skin Melanoma Mice Model: The First Step towards Implementing Lithium Neutron Capture Therapy

Boron neutron capture therapy (BNCT) is one of the promising treatment methods for malignant melanoma. The main issue of this technology is the insufficient selectivity of ¹⁰B accumulation in tumor cells. As a result of the neutron absorption by boron, an 84% energy release occurred within the cell by the nuclear reaction ¹⁰B (n, α)⁷Li, which lead to tumor cell death. The use of lithium instead of boron brings a new unique opportunity-local 100% energy release-since all products of the ⁶Li (n, α)³H reaction have high linear energy transfer characteristics. The aim of this study was to determine the concentrations of Li in the tumor, skin, blood, brain and kidney in experimental animals with B16 melanoma and to analyze the potential Li toxicity after lithium carbonate administration at single doses of 300 and 400 mg/kg. Lithium carbonate was chosen since there is a long-term experience of its use in clinical practice for the treatment of psychiatric disorders. The inductively coupled plasma atomic emission spectrometry was used to evaluate Li concentrations in tissue samples. The accumulation efficiency of Li in the tumor was the highest at a time point of 30 min (22.4 µg/g; at a dose of 400 mg/kg). Despite the high lithium accumulation in the kidneys, the pathological changes in kidney tissues were not found. Thus, lithium may actually be used for the Li-NCT development and future studies can be conducted using ⁶Li and following irradiation of tumor cells using the schemes of lithium administration tested in this work.

Elimination of Cancer Cells in Co-Culture: Role of Different Nanocarriers in Regulation of CD47 and Calreticulin-Induced Phagocytosis

Under healthy conditions, pro- and anti-phagocytic signals are balanced. Cluster of Differentiation 47 (CD47) is believed to act as an anti-phagocytic marker that is highly expressed on multiple types of human cancer cells including acute myeloid leukemia (AML) and lung and liver carcinomas, allowing them to escape phagocytosis by macrophages. Downregulating CD47 on cancer cells discloses calreticulin (CRT) to macrophages and recovers their phagocytic activity. Herein, we postulate that using a modified graphene oxide (GO) carrier to deliver small interfering RNA (siRNA) CD47 (CD47_siRNA) in AML, A549 lung, and HepG2 liver cancer cells in co-culture in vitro will silence CD47 and flag cancer cells for CRT-mediated phagocytosis. Results showed a high knockdown efficiency of CD47 and a significant increase in CRT levels simultaneously by using GO formulation as carriers in all used cancer cell lines. The presence of CRT on cancer cells was significantly higher than levels before knockdown of CD47 and was required to achieve phagocytosis in co-culture with human macrophages. Lipid nanoparticles (LNPs) and modified boron nitride nanotubes (BNPs) were used to carry CD47_siRNA, and the knockdown efficiency values of CD47 were compared in three cancer cells in co-culture, with an achieved knockdown efficiency of >95% using LNPs as carriers. Interestingly, the high efficiency of CD47 knockdown was obtained by using the LNPs and BNP carriers; however, an increase in CRT levels on cancer cells was not required for phagocytosis to happen in co-culture with human macrophages, indicating other pathways' involvement in the phagocytosis process. These findings highlight the roles of 2D (graphene oxide), 1D (boron nitride nanotube), and "0D" (lipid nanoparticle) carriers for the delivery of siRNA to eliminate cancer cells in co-culture, likely through different phagocytosis pathways in multiple types of human cancer cells. Moreover, these results provide an explanation of immune therapies that target CD47 and the potential use of these carriers in screening drugs for such therapies in vitro.

Antibacterial, UV-Protective, Hydrophobic, Washable, and Heat-Resistant BN-Based Nanoparticle-Coated Textile Fabrics: Experimental and Theoretical Insight

The use of nanoparticles (NPs) to modify the surface of cotton fabric is a promising approach to endowing the material with a set of desirable characteristics that can significantly expand the functionality, wear comfort, and service life of textile products. Herein, two approaches to modifying the surface of hexagonal boron nitride (h-BN) NPs with a hollow core and a smooth surface by treatment with maleic anhydride (MA) and diethylene triamine (DETA) were studied. The DETA and MA absorption on the surface of h-BN and the interaction of surface-modified h-NPs with cellulose as the main component of cotton were modeled using density functional theory with the extended Perdew-Burke-Ernzerhof functional. Theoretical modeling showed that the use of DETA as a binder agent can increase the adhesion strength of BN NPs to textile fabric due to the simultaneous hydrogen bonds with cellulose and BN. Due to the difference in zeta potentials (-38.4 vs -25.8 eV), MA-modified h-BN NPs form a stable suspension, while DETA-modified BN NPs tend to agglomerate. Cotton fabric coated with surface-modified NPs exhibits an excellent wash resistance and high hydrophobicity with a water contact angle of 135° (BN-MA) and 146° (BN-DETA). Compared to the original textile material, treatment with MA- and DETA-modified h-BN NPs increases heat resistance by 10% (BN-MA fabric) and 15% (BN-DETA fabric). Cotton fabrics coated with DETA- and MA-modified BN NPs show enhanced antibacterial activity against Escherichia coli U20 and Staphylococcus aureus strains and completely prevent the formation of an E. coli biofilm. The obtained results are important for the further development of fabrics for sports and medical clothing as well as wound dressings.

Sustainable Synthesis of Highly Biocompatible 2D Boron Nitride Nanosheets

2D ultrafine nanomaterials today represent an emerging class of materials with very promising properties for a wide variety of applications. Biomedical fields have experienced important new achievements with technological breakthroughs obtained from 2D materials with singular properties. Boron nitride nanosheets are a novel 2D layered material comprised of a hexagonal boron nitride network (BN) with interesting intrinsic properties, including resistance to oxidation, extreme mechanical hardness, good thermal conductivity, photoluminescence, and chemical inertness. Here, we investigated different methodologies for the exfoliation of BN nanosheets (BNNs), using ball milling and ultrasound processing, the latter using both an ultrasound bath and tip sonication. The best results are obtained using tip sonication, which leads to the formation of few-layered nanosheets with a narrow size distribution. Importantly, it was observed that with the addition of pluronic acid F127 to the medium, there was a significant improvement in the BN nanosheets (BNNs) production yield. Moreover, the resultant BNNs present improved stability in an aqueous solution. Cytotoxicity studies performed with HeLa cells showed the importance of taking into account the possible interferences of the nanomaterial with the selected assay. The prepared BNNs coated with pluronic presented improved cytotoxicity at concentrations up to 200 μg mL^-1 with more than 90% viability after 24 h of incubation. Confocal microscopy also showed high cell internalization of the nanomaterials and their preferential biodistribution in the cell cytoplasm.

Optical Characteristics of Indocyanine Green J-Aggregates Induced by Cisplatin for Phototheranostic Applications

The development of an optical system for combinatorial theranostics is of significant interest. Clinical translation of such theranostic agents need to cross several barriers. Herein, we have developed a facile method for the preparation of J-aggregates using FDA approved agents, namely, NIR fluorophore indocyanine green (ICG) and a chemotherapeutic drug, cisplatin (CDDP), which induces ICG to form indocyanine green J-aggregates (IJAs). The formation of IJAs has been characterized by the formation of a new absorption peak centered at ∼896 nm. The existing methods to synthesize IJAs have used several harsh reaction conditions, such as elevated temperatures, for a prolonged time duration (∼60 days). To the best of our knowledge, for the first time, we have reported the formation of IJAs assisted by CDDP at 37 °C temperature within 12 h. The presence of CDDP in ICG favors IJA formation and thereby reduces the harshness of the reaction conditions in the conventionally followed protocols. Moreover, the presence of CDDP can facilitate photoactivated combinatorial therapy. The as synthesized IJA optical system has superior properties to those of free ICG, in terms of diagnostic and therapeutic capabilities (being activatable at ∼896 nm wavelength, which can achieve deeper tissue penetration) and excellent optical and storage stability. The facile synthesis proposed along with CDDP incorporation makes the optical system a clinically relevant one-component theranostic agent.

Boron attenuated diethylnitrosamine induced hepatocellular carcinoma in C3H/HeN mice via alteration of oxidative stress and apoptotic pathway

BACKGROUND

Reactive oxygen species (ROS) regulate various cellular signaling pathways and play an important role in the occurrence and development of hepatocellular carcinoma (HCC). Excessive accumulation of ROS can promote HCC. Trace element boron has a wide range of biological effects, including anti-oxidation, anti-tumor, immune regulation and so on.

METHODS

In this study, we investigated the anticancer effects of Sodium tetraborate decahydrate (NaB) in improving oxidative stress and regulating apoptosis in mouse HCC. HCC was induced by intraperitoneal injection of diethylnitrosamine (DEN) 25 mg/kg once at the age of 2 weeks and 100 mg/kg again at the age of 6 weeks in healthy C3H/HeN male mice. At 8 weeks of age, different concentrations of NaB were given intragastric treatment once a day for 20 weeks. Oxidative stress markers, antioxidant status and liver enzyme analysis were detected to evaluate the effectiveness of NaB in inhibiting cancer induction. The anticancer properties of NaB were confirmed by observing the liver index and morphology, and analyzing the expression of apoptotic genes and proteins. Our results showed that boron significantly reduced the production of ROS, and down-regulated the expression of the anti-apoptotic protein Bcl2 and up-regulated the expression of the pro-apoptotic proteins P53, Bax, and caspase 3.

CONCLUSION

Boron has great potential to reduce the effects of oxidative stress, which may help it inhibit the progression of HCC.

Polyglycerol Functionalized 10 B Enriched Boron Carbide Nanoparticle as an Effective Bimodal Anticancer Nanosensitizer for Boron Neutron Capture and Photothermal Therapies

Boron neutron capture therapy (BNCT) is a non-invasive cancer treatment with little adverse effect utilizing nuclear fission of ¹⁰ B upon neutron irradiation. While neutron source has been developed from a nuclear reactor to a compact accelerator, only two kinds of drugs, boronophenylalanine and sodium borocaptate, have been clinically used for decades despite their low tumor specificity and/or retentivity. To overcome these challenges, various boron-containing nanomaterials, or "nanosensitizers", have been designed based on micelles, (bio)polymers and inorganic nanoparticles. Among them, inorganic nanoparticles such as boron carbide can include a much higher ¹⁰ B content, but successful in vivo applications are very limited. Additionally, recent reports on the photothermal effect of boron carbide are motivating for the addition of another modality of photothermal therapy. In this study, ¹⁰ B enriched boron carbide (¹⁰ B₄ C) nanoparticle is functionalized with polyglycerol (PG), giving ¹⁰ B₄ C-PG with enough dispersibility in a physiological environment. Pharmacokinetic experiments show that ¹⁰ B₄ C-PG fulfills the following three requirements for BNCT; 1) low intrinsic toxicity, 2) ¹⁰ B in tumor/tumor tissue (wt/wt) ≥ 20 ppm, and 3) ¹⁰ B concentrations in tumor/blood ≥ 3. In vivo study reveals that neutron irradiation after intravenous administration of ¹⁰ B₄ C-PG suppresses cancer growth significantly and eradicates cancer with the help of near-infrared light irradiation.

Recent Progress in Fabrication and Application of BN Nanostructures and BN-Based Nanohybrids

Due to its unique physical, chemical, and mechanical properties, such as a low specific density, large specific surface area, excellent thermal stability, oxidation resistance, low friction, good dispersion stability, enhanced adsorbing capacity, large interlayer shear force, and wide bandgap, hexagonal boron nitride (h-BN) nanostructures are of great interest in many fields. These include, but are not limited to, (i) heterogeneous catalysts, (ii) promising nanocarriers for targeted drug delivery to tumor cells and nanoparticles containing therapeutic agents to fight bacterial and fungal infections, (iii) reinforcing phases in metal, ceramics, and polymer matrix composites, (iv) additives to liquid lubricants, (v) substrates for surface enhanced Raman spectroscopy, (vi) agents for boron neutron capture therapy, (vii) water purifiers, (viii) gas and biological sensors, and (ix) quantum dots, single photon emitters, and heterostructures for electronic, plasmonic, optical, optoelectronic, semiconductor, and magnetic devices. All of these areas are developing rapidly. Thus, the goal of this review is to analyze the critical mass of knowledge and the current state-of-the-art in the field of BN-based nanomaterial fabrication and application based on their amazing properties.

Synergistic Effect of Reinforced Multiwalled Carbon Nanotubes and Boron Nitride Nanosheet-Based Hybrid Piezoelectric PLLA Scaffold for Efficient Bone Tissue Regeneration

Electrospun poly(l-lactic acid) nanofibers (PLLANFs) have been receiving considerable attention in bone tissue engineering (BTE) due to their tunable biodegradability and remarkable in vitro and in vivo biocompatibility. However, deterioration in the mechanical strength of PLLANFs during the regeneration process leads to low osteoinductive performances. Additionally, their high hydrophobicity and limited piezoelectric properties have to be addressed concerning BTE. Herein, we report an efficient approach for fabricating high-performance PLLANF hybrid scaffolds for BTE by reinforcing amphiphilic triblock copolymer pluronic F-127 (PL)-functionalized nanofillers (PL-functionalized carboxylated multiwalled carbon nanotubes (PL-cMWCNTs) and PL-functionalized exfoliated boron nitride nanosheets (PL-EBN)). The synergistic reinforcement effect from one-dimensional (1D) electrically conducting PL-cMWCNTs and two-dimensional (2D) piezoelectric PL-EBN was remarkable in PLLANFs, and the obtained PL-Hybrid (PL-cMWCNTs + PL-EBN) reinforced scaffolds have outperformed the mechanical strength, wettability, and piezoelectric performances of pristine PLLANFs. Consequently, in vitro biocompatibility results reveal the enhanced proliferation of MC3T3-E1 cells on PL-Hybrid nanofiber scaffolds. Furthermore, the ALP activity, ARS staining, and comparable osteogenic gene expression results demonstrated significant osteogenic differentiation of MC3T3-E1 cells on PL-Hybrid nanofiber scaffolds than on the pristine PLLANF scaffold. Thus, the reported approach for constructing high-performance piezoelectric biodegradable scaffolds for BTE by the synergistic effect of PL-cMWCNTs and PL-EBN holds great promise in tissue engineering applications.

Nano-Based Theranostic Platforms for Breast Cancer: A Review of Latest Advancements

Breast cancer (BC) is a highly metastatic multifactorial disease with various histological and molecular subtypes. Due to recent advancements, the mortality rate in BC has improved over the past five decades. Detection and treatment of many cancers are now possible due to the application of nanomedicine in clinical practice. Nanomedicine products such as Doxil^® and Abraxane^® have already been extensively used for BC adjuvant therapy with favorable clinical outcomes. However, these products were designed initially for generic anticancer purposes and not specifically for BC treatment. With a better understanding of the molecular biology of BC, several novel and promising nanotherapeutic strategies and devices have been developed in recent years. In this context, multi-functionalized nanostructures are becoming potential carriers for enhanced chemotherapy in BC patients. To design these nanostructures, a wide range of materials, such as proteins, lipids, polymers, and hybrid materials, can be used and tailored for specific purposes against BC. Selective targeting of BC cells results in the activation of programmed cell death in BC cells and can be considered a promising strategy for managing triple-negative BC. Currently, conventional BC screening methods such as mammography, digital breast tomosynthesis (DBT), ultrasonography, and magnetic resonance imaging (MRI) are either costly or expose the user to hazardous radiation that could harm them. Therefore, there is a need for such analytical techniques for detecting BC that are highly selective and sensitive, have a very low detection limit, are durable, biocompatible, and reproducible. In detecting BC biomarkers, nanostructures are used alone or in conjunction with numerous molecules. This review intends to highlight the recent advances in nanomedicine in BC treatment and diagnosis, emphasizing the targeting of BC cells that overexpress receptors of epidermal growth factors. Researchers may gain insight from these strategies to design and develop more tailored nanomedicine for BC to achieve further improvements in cancer specificity, antitumorigenic effects, anti-metastasis effects, and drug resistance reversal effects.

Multifunctional Hybrid MoS2-PEGylated/Au Nanostructures with Potential Theranostic Applications in Biomedicine

In this work, flower-like molybdenum disulfide (MoS₂) microspheres were produced with polyethylene glycol (PEG) to form MoS₂-PEG. Likewise, gold nanoparticles (AuNPs) were added to form MoS₂-PEG/Au to investigate its potential application as a theranostic nanomaterial. These nanomaterials were fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), photoelectron X-ray spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), cyclic voltammetry and impedance spectroscopy. The produced hierarchical MoS₂-PEG/Au microstructures showed an average diameter of 400 nm containing distributed gold nanoparticles, with great cellular viability on tumoral and non-tumoral cells. This aspect makes them with multifunctional characteristics with potential application for cancer diagnosis and therapy. Through the complete morphological and physicochemical characterization, it was possible to observe that both MoS₂-PEG and MoS₂-PEG/Au showed good chemical stability and demonstrated noninterference in the pattern of the cell nucleus, as well. Thus, our results suggest the possible application of these hybrid nanomaterials can be immensely explored for theranostic proposals in biomedicine.

Clinical Viability of Boron Neutron Capture Therapy for Personalized Radiation Treatment

Simple Summary

Usually, for dose planning in radiotherapy, the tumor is delimited as a volume on the image of the patient together with other clinical considerations based on populational evidence. However, the same prescription dose can provide different results, depending on the patient. Unfortunately, the biological aspects of the tumor are hardly considered in dose planning. Boron Neutron Capture Radiotherapy enables targeted treatment by incorporating boron-10 at the cellular level and irradiating with neutrons of a certain energy so that they produce nuclear reactions locally and almost exclusively damage the tumor cell. This technique is not new, but modern neutron generators and more efficient boron carriers have reactivated the clinical interest of this technique in the pursuit of more precise treatments. In this work, we review the latest technological facilities and future possibilities for the clinical implementation of BNCT and for turning it into a personalized therapy.

Abstract

Boron Neutron Capture Therapy (BNCT) is a promising binary disease-targeted therapy, as neutrons preferentially kill cells labeled with boron (¹⁰B), which makes it a precision medicine treatment modality that provides a therapeutic effect exclusively on patient-specific tumor spread. Contrary to what is usual in radiotherapy, BNCT proposes cell-tailored treatment planning rather than to the tumor mass. The success of BNCT depends mainly on the sufficient spatial biodistribution of ¹⁰B located around or within neoplastic cells to produce a high-dose gradient between the tumor and healthy tissue. However, it is not yet possible to precisely determine the concentration of ¹⁰B in a specific tissue in real-time using non-invasive methods. Critical issues remain to be resolved if BNCT is to become a valuable, minimally invasive, and efficient treatment. In addition, functional imaging technologies, such as PET, can be applied to determine biological information that can be used for the combined-modality radiotherapy protocol for each specific patient. Regardless, not only imaging methods but also proteomics and gene expression methods will facilitate BNCT becoming a modality of personalized medicine. This work provides an overview of the fundamental principles, recent advances, and future directions of BNCT as cell-targeted cancer therapy for personalized radiation treatment.

China’s radiopharmaceuticals on expressway: 2014–2021

This review provides an essential overview on the progress of rapidly-developing China’s radiopharmaceuticals in recent years (2014–2021). Our discussion reflects on efforts to develop potential, preclinical, and in-clinical radiopharmaceuticals including the following areas: (1) brain imaging agents, (2) cardiovascular imaging agents, (3) infection and inflammation imaging agents, (4) tumor radiopharmaceuticals, and (5) boron delivery agents (a class of radiopharmaceutical prodrug) for neutron capture therapy. Especially, the progress in basic research, including new radiolabeling methodology, is highlighted from a standpoint of radiopharmaceutical chemistry. Meanwhile, we briefly reflect on the recent major events related to radiopharmaceuticals along with the distribution of major R&D forces (universities, institutions, facilities, and companies), clinical study status, and national regulatory supports. We conclude with a brief commentary on remaining limitations and emerging opportunities for China’s radiopharmaceuticals.

Polymer-Stabilized Elemental Boron Nanoparticles for Boron Neutron Capture Therapy: Initial Irradiation Experiments

Sufficient boron-10 isotope (10B) accumulation by tumor cells is one of the main requirements for successful boron neutron capture therapy (BNCT). The inability of the clinically registered 10B-containing borophenylalanine (BPA) to maintain a high boron tumor concentration during neutron irradiation after a single injection has been partially solved by its continuous infusion; however, its lack of persistence has driven the development of new compounds that overcome the imperfections of BPA. We propose using elemental boron nanoparticles (eBNPs) synthesized by cascade ultrasonic dispersion and destruction of elemental boron microparticles and stabilized with hydroxyethylcellulose (HEC) as a core component of a novel boron drug for BNCT. These HEC particles are stable in aqueous media and show no apparent influence on U251, U87, and T98G human glioma cell proliferation without neutron beam irradiation. In BNCT experiments, cells incubated with eBNPs or BPA at an equivalent concentration of 40 µg 10B/mL for 24 h or control cells without boron were irradiated at an accelerator-based neutron source with a total fluence of thermal and epithermal neutrons of 2.685, 5.370, or 8.055 × 1012/cm2. The eBNPs significantly reduced colony-forming capacity in all studied cells during BNCT compared to BPA, verified by cell-survival curves fit to the linear-quadratic model and calculated radiobiological parameters, though the effect of both compounds differed depending on the cell line. The results of our study warrant further tumor targeting-oriented modifications of synthesized nanoparticles and subsequent in vivo BNCT experiments.

The Development of Boron Analysis and Imaging in Boron Neutron Capture Therapy (BNCT)

Boron neutron capture therapy (BNCT) is a selective biological targeted nuclide technique for cancer therapy. It has the following attractive features: good targeting, high effectiveness, and causes slight damage to surrounding healthy tissue compared with other traditional methods. It has been considered as one of the promising methods for the treatment of various cancers. Measuring ¹⁰B concentrations is vital for BNCT. However, the existing technology and equipment cannot satisfy the real-time and accurate measurement requirements, and more efficient methods are in demand. The development of methods and imaging applied in BNCT to help measure boron concentration is described in this review.

Radionanomedicine: Advanced Strategy for Precision Theranostics of Breast Cancer

Breast carcinoma remains one of the most common and fatal cancers, and even though a series of general therapeutic approaches have been used to treat breast cancer, their outcomes are significantly affected by a variety of side effects. However, nanomedicine could offer novel strategies for dealing with breast carcinoma. In fact, an increasing number of radionanomedicine approaches have recently been used in both diagnostics and therapy. To highlight this trend, the aim of the current review is to systemically summarize the latest advances in radionanomedicine, including single-modular imaging, multiple-modular imaging, and nanomedicine-based theranostics. Barriers to clinical application, the development of next-generation radionanomedicine, and challenges associated with future design are also discussed.

Hadrontherapy techniques for breast cancer

Radiotherapy plays a key role in breast cancer treatment, and recent technical advances have been made to improve the therapeutic window by limiting the risk of radiation-induced toxicity or by increasing tumor control. Hadrontherapy is a form a radiotherapy relying on particle beams; compared with photon beams, particle beams have specific physical, radiobiological and immunological properties, which can be valuable in diverse clinical situations. To date, available hadrontherapy techniques for breast cancer irradiation include proton therapy, carbon ion radiation therapy, fast neutron therapy and boron neutron capture therapy. This review analyzes the current rationale and level of evidence for each hadrontherapy technique for breast cancer.

Synthesis and Preliminary Biological Assessment of Carborane-Loaded Theranostic Nanoparticles to Target Prostate-Specific Membrane Antigen

Boron neutron capture therapy (BNCT) is an encouraging therapeutic modality for cancer treatment. Prostate-specific membrane antigen (PSMA) is a cell membrane protein that is abundantly overexpressed in prostate cancer and can be targeted with radioligand therapies to stimulate clinical responses in patients. In principle, a spatially targeted neutron beam together with specifically targeted PSMA ligands could enable prostate cancer-targeted BNCT. Thus, we developed and tested PSMA-targeted poly(lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-b-PEG) nanoparticles (NPs) loaded with carborane and tethered to the radiometal chelator deferoxamine B (DFB) for simultaneous positron emission tomography (PET) imaging and selective delivery of boron to prostate cancer. Monomeric PLGA-b-PEGs were covalently functionalized with either DFB or the PSMA ligand ACUPA. Different nanoparticle formulations were generated by nanoemulsification of the corresponding unmodified and DFB- or ACUPA-modified monomers in varying percent fractions. The nanoparticles were efficiently labeled with ⁸⁹Zr and were subjected to in vitro and in vivo evaluation. The optimized DFB(25)ACUPA(75) NPs exhibited strong in vitro binding to PSMA in direct binding and competition radioligand binding assays in PSMA(+) PC3-Pip cells. [⁸⁹Zr]DFB(25) NPs and [⁸⁹Zr]DFB(25)ACUPA(75) NPs were injected to mice with bilateral PSMA(-) PC3-Flu and PSMA(+) PC3-Pip dual xenografts. The NPs demonstrated twofold superior accumulation in PC3-Pip tumors to that of PC3-Flu tumors with a tumor/blood ratio of 25; however, no substantial effect of the ACUPA ligands was detected. Moreover, fast release of carborane from the NPs was observed, resulting in a low boron delivery to tumors in vivo. In summary, these data demonstrate the synthesis, characterization, and initial biological assessment of PSMA-targeted, carborane-loaded PLGA-b-PEG nanoparticles and establish the foundation for future efforts to enable their best use in vivo.

Rapid and delayed effects of single-walled carbon nanotubes in glioma cells

Single-walled carbon nanotubes (SWCNTs) demonstrate a strong potential as an optically activated theranostic nano-agent. However, using SWCNTs in theranostics still requires revealing mechanisms of the SWCNT-mediated effects on cellular functions. Even though rapid and delayed cellular responses can differ significantly and may lead to undesirable consequences, understanding of these mechanisms is still incomplete. We demonstrate that introducing short (150-250 nm) SWCNTs into C6 rat glioma cells leads to SWCNT-driven effects that show pronounced time dependence. Accumulation of SWCNTs is carried out due to endocytosis with modification of the actin cytoskeleton but not accompanied with autophagy. Its initial stage launches a rapid cellular response via significantly heightened mitochondrial membrane potential and superoxide anion radical production, satisfying the cell demand of energy for SWCNT transfer inside the cytoplasm. In the long term, SWCNTs agglomerate to micron-sized structures surrounded by highly active mitochondria having parameters return to control values. SWCNTs postponed effects are also manifested themselves in the suppression of the cell proliferative activity with further restoration after five passages. These results demonstrate relative cellular inertness and safety of SWCNTs eliminating possible side effects caused by optically activated theranostic applications.

Enzyme-instructed supramolecular assemblies promote intracellular boron accumulation for boron neutron capture therapy

Selective accumulation of boron agents in cancer cells is of critical importance for BNCT. Here we involve enzyme-instructed supramolecular assembly (EISA) to facilitate the accumulation of a typical boron agent borylphenylalanine (BPA) in cancer cells. By covalently conjugating BPA to the phosphorylated assembly precursor, the boron-bearing precursors undergo phosphatase-catalyzed dephosphorylation to yield assembly molecules, which then self-assemble to form nanomaterials. Due to the up-regulated phosphatase activity of cancer cells, kinetic preference allows the EISA to accumulate boron in HeLa cells selectively. Interestingly, by attaching BPA on the backbone or side-chain of precursor, the boron-bearing isomers show different assembly propensity with time-dependent morphology change, which leads to the differentiated accumulation of boron inside cells. Overall, the optimized boron-bearing assembly precursor could significantly improve the boron accumulation compared with BPA in cancer cells. In this study, we have demonstrated a convenient method to introduce boron agents to cancer cells. We envision that the EISA-mediated accumulation of boron will be helpful in the design of boron agents to facilitate BNCT treatment.

Biodegradable and Peroxidase-Mimetic Boron Oxynitride Nanozyme for Breast Cancer Therapy

Nanomaterials having enzyme-like activities are recognized as potentially important self-therapeutic nanomedicines. Herein, a peroxidase-like artificial enzyme is developed based on novel biodegradable boron oxynitride (BON) nanostructures for highly efficient and multi-mode breast cancer therapies. The BON nanozyme catalytically generates cytotoxic hydroxyl radicals, which induce apoptosis of 4T1 cancer cells and significantly reduce the cell viability by 82% in 48 h. In vivo experiment reveals a high potency of the BON nanozyme for breast tumor growth inhibitions by 97% after 14-day treatment compared with the control, which are 10 times or 1.3 times more effective than the inert or B-releasing boron nitride (BN) nanospheres, respectively. This work highlights the BON nanozyme and its functional integrations within the BN nanomedicine platform for high-potency breast cancer therapies.

Boron rich nanotube drug carrier system is suited for boron neutron capture therapy

Boron neutron capture therapy (BNCT) is a two-step therapeutic process that utilizes Boron-10 in combination with low energy neutrons to effectively eliminate targeted cells. This therapy is primarily used for difficult to treat head and neck carcinomas; recent advances have expanded this method to cover a broader range of carcinomas. However, it still remains an unconventional therapy where one of the barriers for widespread adoption is the adequate delivery of Boron-10 to target cells. In an effort to address this issue, we examined a unique nanoparticle drug delivery system based on a highly stable and modular proteinaceous nanotube. Initially, we confirmed and structurally analyzed ortho-carborane binding into the cavities of the nanotube. The high ratio of Boron to proteinaceous mass and excellent thermal stability suggest the nanotube system as a suitable candidate for drug delivery into cancer cells. The full physicochemical characterization of the nanotube then allowed for further mechanistic molecular dynamic studies of the ortho-carborane uptake and calculations of corresponding energy profiles. Visualization of the binding event highlighted the protein dynamics and the importance of the interhelical channel formation to allow movement of the boron cluster into the nanotube. Additionally, cell assays showed that the nanotube can penetrate outer membranes of cancer cells followed by localization around the cells' nuclei. This work uses an integrative approach combining experimental data from structural, molecular dynamics simulations and biological experiments to thoroughly present an alternative drug delivery device for BNCT which offers additional benefits over current delivery methods.

Nanoparticles as a Tool in Neuro-Oncology Theranostics

The rapid growth of nanotechnology and the development of novel nanomaterials with unique physicochemical characteristics provides potential for the utility of nanomaterials in theranostics, including neuroimaging, for identifying neurodegenerative changes or central nervous system malignancy. Here we present a systematic and thorough review of the current evidence pertaining to the imaging characteristics of various nanomaterials, their associated toxicity profiles, and mechanisms for enhancing tropism in an effort to demonstrate the utility of nanoparticles as an imaging tool in neuro-oncology. Particular attention is given to carbon-based and metal oxide nanoparticles and their theranostic utility in MRI, CT, photoacoustic imaging, PET imaging, fluorescent and NIR fluorescent imaging, and SPECT imaging.

Inorganic nanomaterials with rapid clearance for biomedical applications

Inorganic nanomaterials that have inherently exceptional physicochemical properties (e.g., catalytic, optical, thermal, electrical, or magnetic performance) that can provide desirable functionality (e.g., drug delivery, diagnostics, imaging, or therapy) have considerable potential for application in the field of biomedicine. However, toxicity can be caused by the long-term, non-specific accumulation of these inorganic nanomaterials in healthy tissues, preventing their large-scale clinical utilization. Over the past several decades, the emergence of biodegradable and clearable inorganic nanomaterials has offered the potential to prevent such long-term toxicity. In addition, a comprehensive understanding of the design of such nanomaterials and their metabolic pathways within the body is essential for enabling the expansion of theranostic applications for various diseases and advancing clinical trials. Thus, it is of critical importance to develop biodegradable and clearable inorganic nanomaterials for biomedical applications. This review systematically summarizes the recent progress of biodegradable and clearable inorganic nanomaterials, particularly for application in cancer theranostics and other disease therapies. The future prospects and opportunities in this rapidly growing biomedical field are also discussed. We believe that this timely and comprehensive review will stimulate and guide additional in-depth studies in the area of inorganic nanomedicine, as rapid in vivo clearance and degradation is likely to be a prerequisite for the future clinical translation of inorganic nanomaterials with unique properties and functionality.

Stability of Boron Nitride Nanosphere Dispersions in the Presence of Polyelectrolytes

Boron nitride nanospheres (BNNSs) were functionalized with polyelectrolytes. The effect of the polyelectrolyte dose and ionic strength on the charging and aggregation properties was investigated. At appropriate polyelectrolyte doses, charge neutralization occurred, whereas by increasing the dose, charge reversal was observed. The complete coating of the particles was indicated by a plateau in the ζ-potential values, which do not change significantly beyond the dose corresponding to the onset of such a plateau. The dispersions were highly aggregated around the charge neutralization point, while at lower or higher doses, the particles were stable. The salt-induced aggregation experiments revealed that the polyelectrolyte coatings contribute to the colloidal stability of the particles, namely, the critical coagulation concentrations deviated from the one determined for bare BNNSs. The presence of electrostatic and steric interparticle forces induced by the adsorbed polyelectrolyte chains was assumed. The obtained results confirm that the comprehensive investigation of the colloidal stability of BNNS particles is crucial to design stable or unstable dispersions and that polyelectrolytes are suitable agents for both stabilization and destabilization of BNNS dispersions, depending on the purpose of their application.

Theranostics in Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) has the potential to specifically destroy tumor cells without damaging the tissues infiltrated by the tumor. BNCT is a binary treatment method based on the combination of two agents that have no effect when applied individually: ¹⁰B and thermal neutrons. Exclusively, the combination of both produces an effect, whose extent depends on the amount of ¹⁰B in the tumor but also on the organs at risk. It is not yet possible to determine the ¹⁰B concentration in a specific tissue using non-invasive methods. At present, it is only possible to measure the ¹⁰B concentration in blood and to estimate the boron concentration in tissues based on the assumption that there is a fixed uptake of ¹⁰B from the blood into tissues. On this imprecise assumption, BNCT can hardly be developed further. A therapeutic approach, combining the boron carrier for therapeutic purposes with an imaging tool, might allow us to determine the ¹⁰B concentration in a specific tissue using a non-invasive method. This review provides an overview of the current clinical protocols and preclinical experiments and results on how innovative drug development for boron delivery systems can also incorporate concurrent imaging. The last section focuses on the importance of proteomics for further optimization of BNCT, a highly precise and personalized therapeutic approach.

Self-Guiding Polymeric Prodrug Micelles with Two Aggregation-Induced Emission Photosensitizers for Enhanced Chemo-Photodynamic Therapy

Nowadays, aggregation-induced emission luminogens (AIEgens) with reactive oxygen species (ROS) generating ability have been used as photosensitizers for imaging guided photodynamic therapy (PDT). To achieve enhanced antitumor outcomes, combining AIEgens-based PDT with chemotherapy is an efficient strategy. However, the therapeutic efficiency is hampered by the limited cellular uptake efficiency and the appropriate light irradiation occasion. In this paper, a self-guiding polymeric micelle (TB@PMPT) composed of two AIE photosensitizers and a reduction-sensitive paclitaxel prodrug (PTX-SS-N₃) was established for enhanced chemo-photodynamic therapy by a dual-stage light irradiation strategy. When the micelles were accumulated in tumor tissues, the first light irradiation (L₁, 6 min) was utilized to facilitate cellular uptake by "photochemical internalization" (PCI). Then, the intracellular glutathione (GSH) would induce the PTX release, micelles disassembly and the aggregation state change of AIEgens. The fluorescence signal change of two AIEgens-based ratiometric fluorescent probe could not only precisely guide the second light irradiation (L₂, 18 min) for sufficient ROS production, but also monitor the nonfluorescent drug PTX release in turn. Both in vivo and in vitro studies demonstrated that the dual-stage light irradiation strategy employed for TB@PMPT micelles exhibited a superior therapeutic effect over only 24 min continuous light irradiation.

Metal-Protein Hybrid Materials with Desired Functions and Potential Applications

Metal nanohybrids are fast emerging functional nanomaterials with advanced structures, intriguing physicochemical properties, and a broad range of important applications in current nanoscience research. Significant efforts have been devoted toward design and develop versatile metal nanohybrid systems. Among numerous biological components, diverse proteins offer avenues for making advanced multifunctional systems with unusual properties, desired functions, and potential applications. This review discusses the rational design, properties, and applications of metal-protein nanohybrid materials fabricated from proteins and inorganic components. The construction of functional biomimetic nanohybrid materials is first briefly introduced. The properties and functions of these hybrid materials are then discussed. After that, an overview of promising application of biomimetic metal-protein nanohybrid materials is provided. Finally, the key challenges and outlooks related to this fascinating research area are also outlined.

Specific Ion Effects on Aggregation and Charging Properties of Boron Nitride Nanospheres

The charging and aggregation properties of boron nitride nanospheres (BNNSs) were investigated in the presence of electrolytes of different compositions and valences in aqueous suspensions. The influence of mono- and multivalent cations (counterions) and anions (coions) on the colloidal stability of the negatively charged particles was studied over a wide range of salt concentrations. For monovalent ions, similar trends were determined in the stability and charging of the particles irrespective of the salt composition, i.e., no ion-specific effects were observed. Once multivalent counterions were involved, the critical coagulation concentrations (CCCs) decreased with the valence in line with the direct Schulze-Hardy rule. The dependence indicated an intermediate charge density for BNNSs. The influence of the coions on the CCCs was weaker and the destabilization ability followed the inverse Schulze-Hardy rule. The predominant interparticle forces were identified as electrical double-layer repulsion and van der Waals attraction. These findings offer useful information to design stable BNNS dispersions in various applications, where mono- and multivalent electrolytes or their mixtures are present in the samples.

The potential of photodynamic therapy in current breast cancer treatment methodologies

Photodynamic Therapy (PDT) has been known for over a hundred years, and currently gaining in acceptance as an alternative cancer treatment. Light delivery is still a difficult problem in deep cancer treatment with PDT. Only near-infrared light in the 700-1100 nm range can penetrate deeply into the tissue because most tissue chromophores, including oxyhemoglobin, deoxyhemoglobin, melanin and fat, poorly absorb in the near infrared window. The light sources used in PDT are lasers, arc lamps, light-emitting diodes and fluorescent lamps. PDT has been used for many different clinical applications. PDT may be excellent alternative in the treatment and diagnosis of breast cancer compared to the conventional surgery, chemotherapy and radiotherapy. The basic elements of PDT are an appropriate photosensitizer (PS), oxygen, and light. The effectiveness of photodynamic therapy depends on the induction of photocytotoxic reactions, which are the result of light activation of PS), pre-administered to the body. The condition for initiating PDT processes is light absorption by PS and subsequent localized generation of cytotoxic reactive oxygen species. This study is a review of empirical research aimed at improving the therapy and diagnosis of breast cancer using PDT based on the physicochemical differences in healthy and diseased tissues and the tissues undergoing treatment.

Covalent Organic Polymer as a Carborane Carrier for Imaging-Facilitated Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) is an atomic targeted radiotherapy that shows fantastic suppression impact on locally intrusive threatening tumors. One key factor for effective BNCT is to aggregate an adequate concentration (>20 ppm) of ¹⁰B in the cytoplasm of the tumor. Carborane-loaded polymer nanoparticles are promising because of their outstanding biocompatibility and plasma steadiness. In this study, a new class of carborane-loaded nanoscale covalent organic polymers (BCOPs) was prepared by a Schiff base condensation reaction, and their solubility was greatly improved in common solvents via alkyl chain engineering and size tailoring. The obtained BCOP-5T was further functionalized by biocompatible 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene-glycol)-2000] (DSPE-PEG, molecular weight 2000) to form stable aqueous-phase nanoparticles with a hydrodynamic diameter of around 100 nm. After chelating with radioactive copper-64, DSPE-BCOP-5T was tracked by positron emission tomography (PET) imaging and showed significant accumulation in the tumor. DSPE-BCOP-5T + neutron radiation showed remarkable tumor suppression in 4T1 tumor-bearing mice (murine breast cancer). No obvious physical tissue damage and abnormal behavior were observed, demonstrating that the boron delivery was successful and tumor-selective. To conclude, this study presents a theranostic COP-based platform with a well-defined composition, good biocompatibility, and satisfactory tumor accumulation, which is promising for PET imaging, drug delivery, and BNCT.