Boron nitride nanotubes as vehicles for intracellular delivery of fluorescent drugs and probes

Ferroptosis-Based Therapeutic Strategies toward Precision Medicine for Cancer

Ferroptosis is a type of iron-dependent programmed cell death characterized by the dysregulation of iron metabolism and the accumulation of lipid peroxides. This nonapoptotic mode of cell death is implicated in various physiological and pathological processes. Recent findings have underscored its potential as an innovative strategy for cancer treatment, particularly against recalcitrant malignancies that are resistant to conventional therapies. This article focuses on ferroptosis-based therapeutic strategies for precision cancer treatment, covering the molecular mechanisms of ferroptosis, four major types of ferroptosis inducers and their inhibitory effects on diverse carcinomas, the detection of ferroptosis by fluorescent probes, and their implementation in image-guided therapy. These state-of-the-art tactics have manifested enhanced selectivity and efficacy against malignant carcinomas. Given that the administration of ferroptosis in cancer therapy is still at a burgeoning stage, some major challenges and future perspectives are discussed for the clinical translation of ferroptosis into precision cancer treatment.

Biomimetic Boron Nitride Nanoparticles for Targeted Drug Delivery and Enhanced Antitumor Activity

Boron nitride nanomaterials are being increasingly recognized as vehicles for cancer drug delivery that increase drug loading and control drug release because of their excellent physicochemical properties and biocompatibility. However, these nanoparticles are often cleared rapidly by the immune system and have poor tumor targeting effects. As a result, biomimetic nanotechnology has emerged to address these challenges in recent times. Cell-derived biomimetic carriers have the characteristics of good biocompatibility, long circulation time, and strong targeting ability. Here, we report a biomimetic nanoplatform (CM@BN/DOX) prepared by encapsulating boron nitride nanoparticles (BN) and doxorubicin (DOX) together using cancer cell membrane (CCM) for targeted drug delivery and tumor therapy. The CM@BN/DOX nanoparticles (NPs) were able to target cancer cells of the same type on its own initiative through homologous targeting of cancer cell membranes. This led to a remarkable increase in cellular uptake. In vitro simulation of an acidic tumor microenvironment could effectively promote drug release from CM@BN/DOX. Furthermore, the CM@BN/DOX complex exhibited an excellent inhibitory effect against homotypic cancer cells. These findings suggest that CM@BN/DOX are promising in targeted drug delivery and potentially personalized therapy against their homologous tumor.

Fluorescence anisotropy using highly polarized emitting dyes confined inside BNNTs

Polarized fluorescence emission of nanoscale emitters has been extensively studied for applications such as bioimaging, displays, and optical communication. Extending the polarization properties in large assemblies of compact emitters is, however, challenging because of self-aggregation processes, which can induce depolarization effects, quenching, and cancellations of molecular dipoles. Here we use α-sexithiophene (6T) molecules confined inside boron nitride nanotubes (6T@BNNTs) to induce fluorescence anisotropy in a transparent host. The experiments first indicate that individual 6T@BNNTs exhibit a high polarization extinction ratio, up to 700, at room temperature. Using aberration-corrected HRTEM, we show that the fluorescence anisotropy is consistent with a general alignment of encapsulated 6T molecules along the nanotube axis. The molecular alignment is weakly influenced by the nanotube diameter, a phenomenon ascribed to stronger molecule-to-sidewall interactions compared to intermolecular interactions. By stretching a flexible thin film made of transparent polymers mixed with 6T@BNNTs, we induce a macroscopic fluorescence anisotropy within the film. This work demonstrates that the dyes@BNNT system can be used as an easy-to-handle platform to induce fluorescence anisotropy in photonic materials.

Recent Advances in Intelligent Wearable Medical Devices Integrating Biosensing and Drug Delivery

The primary roles of precision medicine are to perform real-time examination, administer on-demand medication, and apply instruments continuously. However, most current therapeutic systems implement these processes separately, leading to treatment interruption and limited recovery in patients. Personalized healthcare and smart medical treatment have greatly promoted research on and development of biosensing and drug-delivery integrated systems, with intelligent wearable medical devices (IWMDs) as typical systems, which have received increasing attention because of their non-invasive and customizable nature. Here, the latest progress in research on IWMDs is reviewed, including their mechanisms of integrating biosensing and on-demand drug delivery. The current challenges and future development directions of IWMDs are also discussed.

In Vitro and In Vivo Cytotoxicity of Boron Nitride Nanotubes: A Systematic Review

Boron nitride nanotubes (BNNTs) are an exciting class of nanomaterials due to their unique chemical and physical characteristics. In recent decades, BNNTs have gained huge attention in research and development for various applications, including as nano-fillers for composites, semiconductor devices, hydrogen storage, and as an emerging material in biomedical and tissue engineering applications. However, the toxicity of BNNTs is not clear, and the biocompatibility is not proven yet. In this review, the role of BNNTs in biocompatibility studies is assessed in terms of their characteristics: cell viability, proliferation, therapeutic outcomes, and genotoxicity, which are vital elements for their prospective use in biomedical applications. A systematic review was conducted utilising the databases Scopus and Web of Science (WOS) (2008-2022). Additional findings were discovered manually by snowballing the reference lists of appropriate reviews. Only English-language articles were included. Finally, the significant analysis and discussion of the chosen articles are presented.

Molecular Dynamics Assessment of Doxorubicin Adsorption on Surface-Modified Boron Nitride Nanotubes (BNNTs)

Loading therapeutic agents on nanocarriers in order to protect them during drug delivery and exclusively targeting damaged tissues has gained substantial significance in biology realms in the past decade. Boron nitride nanotubes have given a new lease on designing nano delivery systems by virtue of their unique properties. The studies are still ongoing to thoroughly identify their chemical characteristics. In this study, we probed into the efficacy of boron nitride nanotubes and the impact of their surface modification by hydroxyl and amine functional groups in interaction with an anticancer drug model, i.e., doxorubicin. Defining the altered electronic properties of the nanotubes as well as the distribution of partial charges were carried out through density functional theory calculations, following the simulation of the drug loading process via molecular dynamics algorithms. The primary outcomes are inferred from systematical energies, van der Waals and electrostatic interactions, radial distribution functions, the number of hydrogen bonds, mean square displacement, diffusion coefficients, and binding free energies. Negative values of van der Waals energies imply a rapid, exothermic adsorption process whereby the contribution of these driving forces is more dominant than electrostatic ones. Ultimately, the values of overall diffusion coefficients of drugs and binding free energies, performed by the MM/PBSA approach, corroborate that the hydroxyl and amine-functionalized nanotubes reinforce the binding strength of the complexes to an approximate extent.

Enhanced photoluminescence of boron nitride quantum dots by encapsulation within polymeric nanoparticles

Boron nitride quantum dots (BNQDs) have been proposed as probes for bioimaging owing their to outstanding photoluminescent properties, although their hydrophobic nature and strong aggregation tendency in aqueous media limit their application in the biomedical field. In this work, we synthesize BNQDs by a liquid exfoliation-solvothermal process under pressure from boron nitride nanoparticles in N,N-dimethylformamide. The BNQDs display an average size of 3.3 ± 0.6 nm, as measured by transmission electron microscopy, and a (100) crystalline structure. In addition, a quantum yield of 21.75 ± 0.20% was achieved. To ensure complete dispersibility in water and prevent possible elimination by renal filtration upon injection, the BNQDs (20% w/w) are encapsulated within poly(ethylene glycol)-b-poly(epsilon-caprolactone) nanoparticles by a simple and scalable nanoprecipitation method, and hybrid nanocomposite particles with significantly stronger photoluminescence than their free counterparts are produced. Finally, their optimal cell compatibility and bioimaging features are demonstrated in vitro in murine macrophage and human rhabdomyosarcoma cell lines.

Boron nitride nanotube scaffolds: emergence of a new era in regenerative medicine

Tissue engineering scaffolds have transformed from passive geometrical supports for cell adhesion, extension and proliferation to active, dynamic systems that can in addition, trigger functional maturation of the cells in response to external stimuli. Such 'smart' scaffolds require the incorporation of active response elements that can respond to internal or external stimuli. One of the key elements that direct the cell fate processes is mechanical stress. Different cells respond to various types and magnitudes of mechanical stresses. The incorporation of a pressure-sensitive element in the tissue engineering scaffold therefore, will aid in tuning the cell response to the desired levels. Boron nitride nanotubes (BNNTs) are analogous to carbon nanotubes and have attracted considerable attention due to their unique amalgamation of chemical inertness, piezoelectric property, biocompatibility and, thermal and mechanical stability. Incorporation of BNNTs in scaffolds confers them with piezoelectric property that can be used to stimulate the cells seeded on them. Biorecognition and solubilization of BNNTs can be engineered through surface functionalization with different biomolecules. Over the years, the importance of BNNT has grown in the realm of healthcare nanotechnology. This review discusses the salient properties of BNNTs, the influence of functionalization on theirin vitroandin vivobiocompatibility, and the uniqueness of BNNT-incorporated tissue engineering scaffolds.

Boron Nitride Nanotube as an Antimicrobial Peptide Carrier: A Theoretical Insight

INTRODUCTION

Nanotube-based drug delivery systems have received considerable attention because of their large internal volume to encapsulate the drug and the ability to penetrate tissues, cells, and bacteria. In this regard, understanding the interaction between the drug and the nanotube to evaluate the encapsulation behavior of the drug in the nanotube is of crucial importance.

METHODS

In this work, the encapsulation process of the cationic antimicrobial peptide named cRW3 in the biocompatible boron nitride nanotube (BNNT) was investigated under the Canonical ensemble (NVT) by molecular dynamics (MD) simulation.

RESULTS

The peptide was absorbed into the BNNT by van der Waals (vdW) interaction between cRW3 and the BNNT, in which the vdW interaction decreased during the simulation process and reached the value of -142.7 kcal·mol-1 at 4 ns.

DISCUSSION

The increase in the potential mean force profile of the encapsulated peptide during the pulling process of cRW3 out of the nanotube showed that its insertion into the BNNT occurred spontaneously and that the inserted peptide had the desired stability. The energy barrier at the entrance of the BNNT caused a pause of 0.45 ns when half of the peptide was inside the BNNT during the encapsulation process. Therefore, during this period, the peptide experienced the weakest movement and the smallest conformational changes.

Nanostructured Biomaterials for Bone Regeneration

This review article addresses the various aspects of nano-biomaterials used in or being pursued for the purpose of promoting bone regeneration. In the last decade, significant growth in the fields of polymer sciences, nanotechnology, and biotechnology has resulted in the development of new nano-biomaterials. These are extensively explored as drug delivery carriers and as implantable devices. At the interface of nanomaterials and biological systems, the organic and synthetic worlds have merged over the past two decades, forming a new scientific field incorporating nano-material design for biological applications. For this field to evolve, there is a need to understand the dynamic forces and molecular components that shape these interactions and influence function, while also considering safety. While there is still much to learn about the bio-physicochemical interactions at the interface, we are at a point where pockets of accumulated knowledge can provide a conceptual framework to guide further exploration and inform future product development. This review is intended as a resource for academics, scientists, and physicians working in the field of orthopedics and bone repair.

Confinement of Dyes inside Boron Nitride Nanotubes: Photostable and Shifted Fluorescence down to the Near Infrared

Fluorescence is ubiquitous in life science and used in many fields of research ranging from ecology to medicine. Among the most common fluorogenic compounds, dyes are being exploited in bioimaging for their outstanding optical properties from UV down to the near IR (NIR). However, dye molecules are often toxic to living organisms and photodegradable, which limits the time window for in vivo experiments. Here, it is demonstrated that organic dye molecules are passivated and photostable when they are encapsulated inside a boron nitride nanotube (dyes@BNNT). The results show that the BNNTs drive an aggregation of the encapsulated dyes, which induces a redshifted fluorescence from visible to NIR-II. The fluorescence remains strong and stable, exempt of bleaching and blinking, over a time scale longer than that of free dyes by more than 10⁴ . This passivation also reduces the toxicity of the dyes and induces exceptional chemical robustness, even in harsh conditions. These properties are highlighted in bioimaging where the dyes@BNNT nanohybrids are used as fluorescent nanoprobes for in vivo monitoring of Daphnia Pulex microorganisms and for diffusion tracking on human hepatoblastoma cells with two-photon imaging.

Real-Time Visualization and Dynamics of Boron Nitride Nanotubes Undergoing Brownian Motion

We report the first real-time imaging of individualized boron nitride nanotubes (BNNTs) via stabilization with a rhodamine surfactant and fluorescence microscopy. We study the rotational and translational diffusion and find them to agree with predictions based on a confined, high-aspect-ratio rigid rod undergoing Brownian motion. We find that the behavior of BNNTs parallels that of individualized carbon nanotubes (CNTs), indicating that BNNTs could also be used as model rigid rods to study soft matter systems, while avoiding the experimental disadvantages of CNTs due to their strong light absorption. The use and further development of our technique and findings will accelerate the application of BNNTs from material engineering to biological studies.

Fluorescent surfactants from common dyes – Rhodamine B and Eosin Y

Eight fluorescent surfactants were synthesized by attaching aliphatic chains of 6, 10, 12, or 16 carbons to the fluorescent dyes Rhodamine B and Eosin Y. The obtained critical micelle concentrations (CMC) demonstrate an increasing CMC with decreasing aliphatic chain length, which is a typical behavior for surfactants. Additionally, fluorescence quantum yield experiments show a decrease in quantum yield with increasing aliphatic chain length, suggesting that the tails can interact with the dye, influencing its excited state. Finally, applications for the fluorescent surfactants were demonstrated; as a cellular stain in Panc-1 cells and as a dispersion and imaging tool for carbon and boron nitride nanotubes. These surfactants could provide a useful tool for a wide array of potential applications, from textile dyes to fluorescence imaging.

Purification of Boron Nitride Nanotubes Enhances Biological Application Properties

Commercially available boron nitride nanotubes (BNNTs) and their purified form (pBNNTs) were dispersed in aqueous solutions with various dispersants, and their cytotoxicity and drug encapsulation capacity were monitored. Our data suggest that pBNNTs showed an average increase in dispersibility of 37.3% in aqueous solution in the presence of 10 different dispersants. In addition, 100 μg of pBNNTs induced an average decrease in cytotoxicity of 27.4% compared to same amount of BNNTs in normal cell lines. The same amount of pBNNTs can encapsulate 10.4-fold more drug (camptothecin) compared to BNNTs. These data suggest that the purification of BNNTs improves several of their properties, which can be applied to biological experiments and are thus essential in the biological application of BNNTs.

Hexagonal Boron Nitrides (White Graphene): A Promising Method for Cancer Drug Delivery

Advances in low-dimensions nanomaterials drug-carrier have rapidly translated into clinical practice. Interestingly, the two-dimensional (2D) nanomaterials of hexagonal boron nitride (h-BN), so-called "white graphite" are relatively less explored compared to the post popular 2D graphene oxide (GO). However, the unique properties of h-BN nanomaterials make them well suited for the delivery of chemotherapeutic in cancer treatment. Recent studies have shown that the h-BN is a potential candidate in biomedical sciences, both as nanocarriers and nano-transducers. In this review, we discuss the various physicochemical properties and important concepts involved in h-BN nanosheets as anticancer drug carriers.

Nanostructured Modulators of Neuroglia

Biological and synthetic nanostructures can influence both glia and neurons in the central nervous system. Neurons represent only a small proportion (about 10%) of cells in the brain, whereas glial cells are the most abundant cell type. Non-targeted nanomedicines are mainly internalized by glia, in particular microglia, and to a lesser extent by astrocytes. Internalized nanomedicines by glia indirectly modify the functional status of neurons. The mechanisms of biochemical, morphological and functional changes of neural cells exposed to nanomedicines are still not well-understood. This minireview provides a cross-section of morphological and biochemical changes in glial cells and neurons exposed to different classes of hard and soft nanostructures.

In vitro investigation of the effects of boron nitride nanotubes and curcumin on DNA damage

BACKROUND

Stem cells provide an opportunity to analyse the effects of xenobiotic on cell viability, differentiation and cell functions. Evaluation of the possible cytotoxic and DNA damaging effects on bone marrow CD34+ stem cells is important for their ability to differentiate into blood cells, and also for bone marrow diseases therapy. Boron nitride nanotubes and curcumin are potential nanoformulation agents that can be used together in the treatment of cancer or bone marrow diseases. Therefore, it is important to evaluate their possible effects on different cell lines.

OBJECTIVES

In this study, it was aimed to evaluate the cytotoxic and DNA damaging effects of boron nitride nanotubes which are commonly used in pyroelectric, piezoelectric and optical applications, but there is not enough information about its biocompatibility. Also, it was intended to research the effects of curcumin being used frequently in treatment processes for antioxidant properties.

METHODS

The possible cytotoxic and DNA damaging effects of boron nitride nanotubes and curcumin on CD34+ cells, HeLa and V79 cells were evaluated by MTT assay and Comet assay, respectively.

RESULTS AND CONCLUSION

Boron nitride nanotubes and curcumin had cytotoxic effects and cause DNA damage on CD34+ cells, HeLa and V79 cells at several concentrations, probably because of increased ROS level. However, there were not concentration - dependent effect and there were controversial toxicity results of the studied cell lines. Its mechanism needs to be enlightened by further analysis for potential targeted drug development. Graphical abstract.

Assessing size-dependent cytotoxicity of boron nitride nanotubes using a novel cardiomyocyte AFM assay

As boron nitride nanotubes (BNNTs) find increased use in numerous applications, potential adverse health effects of BNNT exposure are a growing concern. Current in vitro cytotoxicity studies on BNNTs are inconsistent and even contradictory, likely due to the lack of reference materials, standardized characterization methods and measurement protocols. New approaches, particularly with the potential to reliably relate in vitro to in vivo studies, are critically needed. This work introduces a novel atomic force microscopy (AFM)-based cardiomyocyte assay that reliably assesses the cytotoxicity of a well-characterized boron nitride nanotube reference material, code named BNNT-1. High energy probe sonication was used to modify and control the length of BNNT-1. The polymer polyethylenimine (PEI) was used concurrently with sonication to produce stable, aqueous dispersions of BNNT-1. These dispersions were used to perform a systematic analysis on both the length and height of BNNT-1 via a correlated characterization approach of dynamic light scattering (DLS) and AFM. Cytotoxicity studies using the novel cardiomyocyte AFM model were in agreement with traditional colorimetric cell metabolic assays, both revealing a correlation between tube length and cytotoxicity with longer tubes having higher cytotoxicity. In addition to the size-dependent cytotoxicity, it was found that BNNT-1 exhibits concentration and cell-line dependent cytotoxic effects.

Antimicrobial Applications of Clay Nanotube-Based Composites

Halloysite nanotubes with different outer surface/inner lumen chemistry (SiO₂/Al₂O₃) are natural objects with a 50 nm diameter hollow cylindrical structure, which are able to carry functional compounds both inside and outside. They are promising for biological applications where their drug loading capacity combined with a low toxicity ensures the safe interaction of these nanomaterials with living cells. In this paper, the antimicrobial properties of the clay nanotube-based composites are reviewed, including applications in microbe-resistant biocidal textile, paints, filters, and medical formulations (wound dressings, drug delivery systems, antiseptic sprays, and tissue engineering scaffolds). Though halloysite-based antimicrobial materials have been widely investigated, their application in medicine needs clinical studies. This review suggests the scalable antimicrobial nano/micro composites based on natural tubule clays and outlines research and development perspectives in the field.

Effects of Curcumin on Microglial Cells

Microglia are innate immune system cells which reside in the central nervous system (CNS). Resting microglia regulate the homeostasis of the CNS via phagocytic activity to clear pathogens and cell debris. Sometimes, however, to protect neurons and fight invading pathogens, resting microglia transform to an activated-form, producing inflammatory mediators, such as cytokines, chemokines, iNOS/NO and cyclooxygenase-2 (COX-2). Excessive inflammation, however, leads to damaged neurons and neurodegenerative diseases (NDs), such as Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). Curcumin is a phytochemical isolated from Curcuma longa. It is widely used in Asia and has many therapeutic properties, including antioxidant, anti-viral, anti-bacterial, anti-mutagenic, anti-amyloidogenic and anti-inflammatory, especially with respect to neuroinflammation and neurological disorders (NDs). Curcumin is a pleiotropic molecule that inhibits microglia transformation, inflammatory mediators and subsequent NDs. In this mini-review, we discuss the effects of curcumin on microglia and explore the underlying mechanisms.

Surfactant-assisted individualization and dispersion of boron nitride nanotubes

Boron nitride nanotubes (BNNTs) belong to a novel class of material with useful thermal, electronic and optical properties. However, the study and the development of applications of this material requires the formation of stable dispersions of individual BNNTs in water. Here we address the dispersion of BNNT material in water using surfactants with varying properties. The surfactants were compared based on the quantity of BNNTs dispersed and the quality of the dispersions, as visualized by AFM and cryo-TEM. All surfactants produce dispersions of individualized or small bundles of BNNTs. Of the surfactants tested, high molecular weight, nonionic surfactants suspend the most BNNTs, while ionic surfactants remove the most h-BN impurities. The surfactant dispersions were further characterized by ensemble measurements, such as UV absorption and photoluminescence, dynamic light scattering (DLS), and zeta potential to investigate dispersion stability and quality. These techniques provide a facile strategy for testing future BNNT dispersions. The results of this study reveal that BNNT dispersions in aqueous solution can be tuned to fit a specific application through surfactant selection.

Folate-conjugated, mesoporous silica functionalized boron nitride nanospheres for targeted delivery of doxorubicin

Biomedical application of boron nitride (BN) nanomaterials has recently attracted considerable attentions. BN nanospheres (BNNS) could safely deliver anti-cancer drug into tumor cells, which makes them potential nanocarrier for cancer therapy. However, the poor dispersity in physiological environments and low drug loading capacity severely limit their further applications. Herein, we developed a novel drug delivery system based on folate-conjugated mesoporous silica (MS)-functionalized BNNS (BNMS-FA). Dispersity and drug loading capacity of BNNS were highly improved by MS modification. BNMS-FA complexes were nontoxic up to a concentration of 100 μg/mL, and could be specifically internalized by HeLa and MCF-7 cells via folate receptor-mediated endocytosis. Doxorubicin (DOX) could be loaded onto BNMS-FA complexes with high efficiency via π-π stacking and hydrogen bonding, and showed a sustained release pattern under different pH conditions. BNMS-FA/DOX complexes exhibited superior drug internalization and antitumor efficacy over free DOX, BNNS/DOX and BNMS/DOX complexes, which were considered promising for targeted cancer therapy.

Piezoelectric materials as stimulatory biomedical materials and scaffolds for bone repair

The process of bone repair and regeneration requires multiple physiological cues including biochemical, electrical and mechanical - that act together to ensure functional recovery. Myriad materials have been explored as bioactive scaffolds to deliver these cues locally to the damage site, amongst these piezoelectric materials have demonstrated significant potential for tissue engineering and regeneration, especially for bone repair. Piezoelectric materials have been widely explored for power generation and harvesting, structural health monitoring, and use in biomedical devices. They have the ability to deform with physiological movements and consequently deliver electrical stimulation to cells or damaged tissue without the need of an external power source. Bone itself is piezoelectric and the charges/potentials it generates in response to mechanical activity are capable of enhancing bone growth. Piezoelectric materials are capable of stimulating the physiological electrical microenvironment, and can play a vital role to stimulate regeneration and repair. This review gives an overview of the association of piezoelectric effect with bone repair, and focuses on state-of-the-art piezoelectric materials (polymers, ceramics and their composites), the fabrication routes to produce piezoelectric scaffolds, and their application in bone repair. Important characteristics of these materials from the perspective of bone tissue engineering are highlighted. Promising upcoming strategies and new piezoelectric materials for this application are presented.

STATEMENT OF SIGNIFICANCE

Electrical stimulation/electrical microenvironment are known effect the process of bone regeneration by altering the cellular response and are crucial in maintaining tissue functionality. Piezoelectric materials, owing to their capability of generating charges/potentials in response to mechanical deformations, have displayed great potential for fabricating smart stimulatory scaffolds for bone tissue engineering. The growing interest of the scientific community and compelling results of the published research articles has been the motivation of this review article. This article summarizes the significant progress in the field with a focus on the fabrication aspects of piezoelectric materials. The review of both material and cellular aspects on this topic ensures that this paper appeals to both material scientists and tissue engineers.

Electroactive biomaterials: Vehicles for controlled delivery of therapeutic agents for drug delivery and tissue regeneration

Electrical stimulation for delivery of biochemical agents such as genes, proteins and RNA molecules amongst others, holds great potential for controlled therapeutic delivery and in promoting tissue regeneration. Electroactive biomaterials have the capability of delivering these agents in a localized, controlled, responsive and efficient manner. These systems have also been combined for the delivery of both physical and biochemical cues and can be programmed to achieve enhanced effects on healing by establishing control over the microenvironment. This review focuses on current state-of-the-art research in electroactive-based materials towards the delivery of drugs and other therapeutic signalling agents for wound care treatment. Future directions and current challenges for developing effective electroactive approach based therapies for wound care are discussed.

pH-responsive charge-reversal polymer-functionalized boron nitride nanospheres for intracellular doxorubicin delivery

Background

Anticancer drug-delivery systems (DDSs) capable of responding to the physiological stimuli and efficiently releasing drugs inside tumor cells are highly desirable for effective cancer therapy. Herein, pH-responsive, charge-reversal poly(allylamine hydrochlorid)−citraconic anhydride (PAH-cit) functionalized boron nitride nanospheres (BNNS) were fabricated and used as a carrier for the delivery and controlled release of doxorubicin (DOX) into cancer cells.

Methods

BNNS was synthesized through a chemical vapor deposition method and then functionalized with synthesized charge-reversal PAH-cit polymer. DOX@PAH-cit–BNNS complexes were prepared via step-by-step electrostatic interactions and were fully characterized. The cellular uptake of DOX@PAH-cit–BNNS complexes and DOX release inside cancer cells were visualized by confocal laser scanning microscopy. The in vitro anticancer activity of DOX@ PAH-cit–BNNS was examined using CCK-8 and live/dead viability/cytotoxicity assay.

Results

The PAH-cit–BNNS complexes were nontoxic to normal and cancer cells up to a concentration of 100 µg/mL. DOX was loaded on PAH-cit–BNNS complexes with high efficiency. In a neutral environment, the DOX@PAH-cit–BNNS was stable, whereas the loaded DOX was effectively released from these complexes at low pH condition due to amide hydrolysis of PAH-cit. Enhanced cellular uptake of DOX@PAH-cit–BNNS complexes and DOX release in the nucleus of cancer cells were revealed by confocal microscopy. Additionally, the effective delivery and release of DOX into the nucleus of cancer cells led to high therapeutic efficiency.

Conclusion

Our findings indicated that the newly developed PAH-cit–BNNS complexes are promising as an efficient pH-responsive DDS for cancer therapy.

Piezoelectric Effects of Materials on Bio-Interfaces

Electrical stimulation of cells and tissues is an important approach of interaction with living matter, which has been traditionally exploited in the clinical practice for a wide range of pathological conditions, in particular, related to excitable tissues. Standard methods of stimulation are, however, often invasive, being based on electrodes and wires used to carry current to the intended site. The possibility to achieve an indirect electrical stimulation, by means of piezoelectric materials, is therefore of outstanding interest for all the biomedical research, and it emerged in the latest decade as a most promising tool in many bioapplications. In this paper, we summarize the most recent achievements obtained by our group and by others in the exploitation of piezoelectric nanoparticles and nanocomposites for cell stimulation, describing the important implications that these studies present in nanomedicine and tissue engineering. A particular attention will be also dedicated to the physical modeling, which can be extremely useful in the description of the complex mechanisms involved in the mechanical/electrical transduction, yet also to gain new insights at the base of the observed phenomena.

Evaluation of boron nitride nanotubes and hexagonal boron nitrides as nanocarriers for cancer drugs

AIM

Boron nitride nanotubes (BNNTs) and hexagonal boron nitrides (hBNs) are novel nanostructures with high mechanical strengths, large surface areas and excellent biocompatibilities. Here, the potential use of BNNTs and hBNs as nanocarriers was comparatively investigated for use with cancer drugs.

MATERIALS & METHODS

Doxorubicin (Dox) and folate are used as model drugs and targeting agents, respectively.

RESULTS & DISCUSSION

The obtained results indicate that BNNTs have about a threefold higher Dox loading capacity than hBNs. It was also found that cellular uptake of folate-Dox-BNNTs was much higher when compared with Dox-BNNTs for HeLa cells, due to the presence of folate receptors on the cell surface, leading to increased cancer cell death. In summary, folate and Dox conjugated BNNTs are promising agents in nanomedicine and may have potential drug delivery applications.

Theoretic Study on Dispersion Mechanism of Boron Nitride Nanotubes by Polynucleotides

Due to the unique electrical and mechanical properties of boron nitride nanotubes (BNNT), BNNT has been a promising material for many potential applications, especially in biomedical field. Understanding the dispersion of BNNT in aqueous solution by biomolecules is essential for its use in biomedical applications. In this study, BNNT wrapped by polynucleotides in aqueous solution was investigated by molecular dynamics (MD) simulations. Our results demonstrated that the BNNT wrapped by polynucleotides could greatly hinder the aggregation of BNNTs and improve the dispersion of BNNTs in aqueous solution. Dispersion of BNNTs with the assistance of polynucleotides is greatly affected by the wrapping manner of polynucleotides on BNNT, which mainly depends on two factors: the type of polynucleotides and the radius of BNNT. The interaction between polynucleotides and BNNT(9, 9) is larger than that between polynucleotides and BNNT(5, 5), which leads to the fact that dispersion of BNNT(9, 9) is better than that of BNNT(5, 5) with the assistance of polynucleotides in aqueous solution. Our study revealed the molecular-level dispersion mechanism of BNNT with the assistance of polynucleotides in aqueous solution. It shades a light on the understanding of dispersion of single wall nanotubes by biomolecules.