Using C-doped TiO2 Nanoparticles as a Novel Sonosensitizer for Cancer Treatment

Advances in Nanomaterials for Immunotherapeutic Improvement of Cancer Chemotherapy

Immuno-stimulative effect of chemotherapy (ISECT) is recognized as a potential alternative to conventional immunotherapies, however, the clinical application is constrained by its inefficiency. Metronomic chemotherapy, though designed to overcome these limitations, offers inconsistent results, with effectiveness varying based on cancer types, stages, and patient-specific factors. In parallel, a wealth of preclinical nanomaterials holds considerable promise for ISECT improvement by modulating the cancer-immunity cycle. In the area of biomedical nanomaterials, current literature reviews mainly concentrate on a specific category of nanomaterials and nanotechnological perspectives, while two essential issues are still lacking, i.e., a comprehensive analysis addressing the causes for ISECT inefficiency and a thorough summary elaborating the nanomaterials for ISECT improvement. This review thus aims to fill these gaps and catalyze further development in this field. For the first time, this review comprehensively discusses the causes of ISECT inefficiency. It then meticulously categorizes six types of nanomaterials for improving ISECT. Subsequently, practical strategies are further proposed for addressing inefficient ISECT, along with a detailed discussion on exemplary nanomedicines. Finally, this review provides insights into the challenges and perspectives for improving chemo-immunotherapy by innovations in nanomaterials.

A critical review on the recent trends of photocatalytic, antibacterial, antioxidant and nanohybrid applications of anatase and rutile TiO2 nanoparticles

Titanium dioxide nanoparticles (TiO2 NPs) have become a focal point of research due to their widespread daily use and diverse synthesis methods, including physical, chemical, and environmentally sustainable approaches. These nanoparticles possess unique attributes such as size, shape, and surface functionality, making them particularly intriguing for applications in the biomedical field. The continuous exploration of TiO2 NPs is driven by the quest to enhance their multifunctionality, aiming to create next-generation products with superior performance. Recent research efforts have specifically focused on understanding the anatase and rutile phases of TiO2 NPs and evaluating their potential in various domains, including photocatalytic processes, antibacterial properties, antioxidant effects, and nanohybrid applications. The hypothesis guiding this research is that by exploring different synthesis methods, particularly chemical and environmentally friendly approaches, and incorporating doping and co-doping techniques, the properties of TiO2 NPs can be significantly improved for diverse applications. The study employs a comprehensive approach, investigating the effects of nanoparticle size, shape, dose, and exposure time on performance. The synthesis methods considered encompass both conventional chemical processes and environmentally friendly alternatives, with a focus on how doping and co-doping can enhance the properties of TiO2 NPs. The research unveils valuable insights into the distinct phases of TiO2 NPs and their potential across various applications. It sheds light on the improved properties achieved through doping and co-doping, showcasing advancements in photocatalytic processes, antibacterial efficacy, antioxidant capabilities, and nanohybrid applications. The study concludes by emphasizing regulatory aspects and offering suggestions for product enhancement. It provides recommendations for the reliable application of TiO2 NPs, addressing a comprehensive spectrum of critical aspects in TiO2 NP research and application. Overall, this research contributes to the evolving landscape of TiO2 NP utilization, offering valuable insights for the development of innovative and high-performance products.

A Distinctive Insight into Inorganic Sonosensitizers: Design Principles and Application Domains

Sonodynamic therapy (SDT) as a promising non-invasive anti-tumor means features the preferable penetration depth, which nevertheless, usually can't work without sonosensitizers. Sonosensitizers produce reactive oxygen species (ROS) in the presence of ultrasound to directly kill tumor cells, and concurrently activate anti-tumor immunity especially after integration with tumor microenvironment (TME)-engineered nanobiotechnologies and combined therapy. Current sonosensitizers are classified into organic and inorganic ones, and current most reviews only cover organic sonosensitizers and highlighted their anti-tumor applications. However, there have few specific reviews that focus on inorganic sonosensitizers including their design principles, microenvironment regulation, etc. In this review, inorganic sonosensitizers are first classified according to their design rationales rather than composition, and the action rationales and underlying chemistry features are highlighted. Afterward, what and how TME is regulated based on the inorganic sonosensitizers-based SDT nanoplatform with an emphasis on the TME targets-engineered nanobiotechnologies are elucidated. Additionally, the combined therapy and their applications in non-cancer diseases are also outlined. Finally, the setbacks and challenges, and proposed the potential solutions and future directions is pointed out. This review provides a comprehensive and detailed horizon on inorganic sonosensitizers, and will arouse more attentions on SDT.

An amplified sonodynamic therapy by a nanohybrid of titanium dioxide-gold-polyethylene glycol-curcumin: HeLa cancer cells treatment in 2D monolayer and 3D spheroid models

The utilization of ultrasound (US) to activate sonosensitizers for sonodynamic therapy (SDT) has faced challenges such as low activation efficiency and limited therapeutic outcomes, which have hampered its clinical applications. In this study, a nanohybrid of titanium dioxide-gold-polyethylene glycol-curcumin (TiO2-Au-PEG-Cur NH), as a novel US sensitizer, was synthesized, characterized, and applied for SDT of HeLa cancer cells in 2D monolayer model, and also a 3D spheroid model to bridge the gap between 2D cell culture and in vivo future studies. TiO2-Au-PEG-Cur NH contained TiO2 nanoparticles of 36 ± 11 nm in diameter, PEG-curcumin as a filler, and gold nanoparticles of 21 ± 7 nm in diameter with a high purity and a 35:17 of Ti:Au ratio (W/W), and it had a band gap of 2.4 eV, a zeta potential of -23 ± 7 mV, high stability upon US radiation cycles as well as one year storage. SDT of HeLa cells using TiO2-Au-PEG-Cur NH was investigated in the courses of cytotoxicity assessment in vitro, reactive oxygen species (ROS) generation capability, colony formation, cell migration, and the way to form spheroid. IC50 values of 122 and 38 μg mL-1 were obtained for TiO2-Au-PEG-Cur NH without and with US radiation, respectively. TiO2-Au-PEG-Cur NH not only exhibited an inherent capacity to generate ROS, but also represented an excellent therapeutic performance on the cancer cells through ROS generation and enhanced inhibitory effects on cell migration and spheroid formation.

Nanomaterials-based precision sonodynamic therapy enhancing immune checkpoint blockade: A promising strategy targeting solid tumor

Burgeoning is an evolution from conventional photodynamic therapy (PDT). Thus, sonodynamic therapy (SDT) regulated by nanoparticles (NPs) possesses multiple advantages, including stronger penetration ability, better biological safety, and not reactive oxygen species (ROS)-dependent tumor-killing effect. However, the limitation to tumor inhibition instead of shrinkage and the incapability of eliminating metastatic tumors hinder the clinical potential for SDT. Fortunately, immune checkpoint blockade (ICB) can revive immunological function and induce a long-term immune memory against tumor rechallenges. Hence, synergizing NPs-based SDT with ICB can provide a promising therapeutic outcome for solid tumors. Herein, we briefly reviewed the progress in NPs-based SDT and ICB therapy. We highlighted the synergistic anti-tumor mechanisms and summarized the representative preclinical trials on SDT-assisted immunotherapy. Compared to other reviews, we provided comprehensive and unique perspectives on the innovative sonosensitizers in each trial. Moreover, we also discussed the current challenges and future corresponding solutions.

Comparison of Sonodynamic Treatment Set-Ups for Cancer Cells with Organic Sonosensitizers and Nanosonosensitizers

Cancer sonodynamic therapy (SDT) is the therapeutic strategy of a high-frequency ultrasound (US) combined with a special sonosensitizer that becomes cytotoxic upon US exposure. The growing number of newly discovered sonosensitizers and custom US in vitro treatment solutions push the SDT field into a need for systemic studies and reproducible in vitro experimental set-ups. In the current research, we aimed to compare two of the most used and suitable SDT in vitro set-ups-"sealed well" and "transducer in well"-in one systematic study. We assessed US pressure, intensity, and temperature distribution in wells under US irradiation. Treatment efficacy was evaluated for both set-ups towards cancer cell lines of different origins, treated with two promising sonosensitizer candidates-carbon nanoparticle C60 fullerene (C60) and herbal alkaloid berberine. C60 was found to exhibit higher sonotoxicity toward cancer cells than berberine. The higher efficacy of sonodynamic treatment with a "transducer in well" set-up than a "sealed well" set-up underlined its promising application for SDT in vitro studies. The "transducer in well" set-up is recommended for in vitro US treatment investigations based on its US-field homogeneity and pronounced cellular effects. Moreover, SDT with C60 and berberine could be exploited as a promising combinative approach for cancer treatment.

Recent strategies of carbon dot-based nanodrugs for enhanced emerging antitumor modalities

Nanomaterial-based cancer therapy has recently emerged as a new therapeutic modality with the advantages of minimal invasiveness and negligible normal tissue toxicity over traditional cancer treatments. However, the complex microenvironment and self-protective mechanisms of tumors have suppressed the therapeutic effect of emerging antitumor modalities, which seriously hindered the transformation of these modalities to clinical settings. Due to the excellent biocompatibility, unique physicochemical properties and easy surface modification, carbon dots, as promising nanomaterials in the biomedical field, can effectively improve the therapeutic effect of emerging antitumor modalities as multifunctional nanoplatforms. In this review, the mechanism and limitations of emerging therapeutic modalities are described. Further, the recent advances related to carbon dot-based nanoplatforms in overcoming the therapeutic barriers of various emerging therapies are systematically summarized. Finally, the prospects and potential obstacles for the clinical translation of carbon dot-based nanoplatforms in tumor therapy are also discussed. This review is expected to provide a reference for nanomaterial design and its development for the efficacy enhancement of emerging therapeutic modalities.

Defect Engineering in Biomedical Sciences

With the promotion of nanochemistry research, large numbers of nanomaterials have been applied in vivo to produce desirable cytotoxic substances in response to endogenous or exogenous stimuli for achieving disease-specific therapy. However, the performance of nanomaterials is a critical issue that is difficult to improve and optimize under biological conditions. Defect-engineered nanoparticles have become the most researched hot materials in biomedical applications recently due to their excellent physicochemical properties, such as optical properties and redox reaction capabilities. Importantly, the properties of nanomaterials can be easily adjusted by regulating the type and concentration of defects in the nanoparticles without requiring other complex designs. Therefore, this tutorial review focuses on biomedical defect engineering and briefly discusses defect classification, introduction strategies, and characterization techniques. Several representative defective nanomaterials are especially discussed in order to reveal the relationship between defects and properties. A series of disease treatment strategies based on defective engineered nanomaterials are summarized. By summarizing the design and application of defective engineered nanomaterials, a simple but effective methodology is provided for researchers to design and improve the therapeutic effects of nanomaterial-based therapeutic platforms from a materials science perspective.

Ultrasonic interfacial crosslinking of TiO2-based nanocomposite hydrogels through thiol-norbornene reactions for sonodynamic antibacterial treatment

Nanocomposite (NC) hydrogels used for sonodynamic therapy (SDT) face challenges such as lacking interfacial interactions between the polymers and nanomaterials as well as presenting uneven dispersion of nanomaterials in the hydrogel network, reducing their mechanical properties and treatment efficiency. Here, we demonstrate a promising approach of co-engineering nanomaterials and interfacial crosslinking to expand the materials construction and biomedical applications of NC hydrogels in SDT. In this work, mesoporous silica-coated titanium dioxide nanoparticles with thiolated surface functionalization (TiO₂@MS-SH) are utilized as crosslinkers to react with norbornene-functionalized dextran (Nor-Dex) through ultrasound-triggered thiol-norbornene reactions, forming TiO₂@MS-SH/Nor-Dex NC hydrogels. The TiO₂@MS-SH nanoparticles act not only as multivalent crosslinkers to improve the mechanical properties of hydrogels under ultrasound irradiation but also as reactive oxygen species (ROS) generators to allow the use of TiO₂@MS-SH/Nor-Dex NC hydrogels in SDT applications. Particularly, the TiO₂@MS-SH/Nor-Dex NC hydrogels present tailorable microstructures, properties, and sonodynamic killing of bacteria through the modulation of the ultrasound frequency. Taken together, a versatile TiO₂-based NC hydrogel platform prepared under ultrasonic interfacial crosslinking reactions is developed for advancing the applications in SDT.

Titanium-Based Nanoarchitectures for Sonodynamic Therapy-Involved Multimodal Treatments

Sonodynamic therapy (SDT) has considerably revolutionized the healthcare sector as a viable noninvasive therapeutic procedure. It employs a combination of low-intensity ultrasound and chemical entities, known as a sonosensitizer, to produce cytotoxic reactive oxygen species (ROS) for cancer and antimicrobial therapies. With nanotechnology, several unique nanoplatforms are introduced as a sonosensitizers, including, titanium-based nanomaterials, thanks to their high biocompatibility, catalytic efficiency, and customizable physicochemical features. Additionally, developing titanium-based sonosensitizers facilitates the integration of SDT with other treatment modalities (for example, chemotherapy, chemodynamic therapy, photodynamic therapy, photothermal therapy, and immunotherapy), hence increasing overall therapeutic results. This review summarizes the most recent developments in cancer therapy and tissue engineering using titanium nanoplatforms mediated SDT. The synthesis strategies and biosafety aspects of Titanium-based nanoplatforms for SDT are also discussed. Finally, various challenges and prospects for its further development and potential clinical translation are highlighted.

Single Atom-Doped Nanosonosensitizers for Mutually Optimized Sono/Chemo-Nanodynamic Therapy of Triple Negative Breast Cancer

Sonodynamic therapy (SDT) represents a promising therapeutic modality for treating breast cancer, which relies on the generation of abundant reactive oxygen species (ROS) to induce oxidative stress damage. However, mutant breast cancers, especially triple-negative breast cancer (TNBC), have evolved to acquire specific antioxidant defense functions, significantly limiting the killing efficiency of SDT. Herein, the authors have engineered a distinct single copper atom-doped titanium dioxide (Cu/TiO2 ) nanosonosensitizer with highly catalytic and sonosensitive activities for synergistic chemodynamic and sonodynamic treatment of TNBC. The single-atom Cu is anchored on the most stable Ti vacancies of hollow TiO2 sonosensitizers, which not only substantially improved the catalytic activity of Cu-mediated Fenton-like reaction, but also considerably augmented the sonodynamic efficiency of TiO2 by facilitating the separation of electrons (e- ) and holes (h+ ). Both the in vitro and in vivo studies demonstrate that the engineered single atom-doped nanosonosensitizers effectively achieved the significantly inhibitory effect of TNBC, providing a therapeutic paradigm for non-invasive and safe tumor elimination through the mutual process of sono/chemo-nanodynamic therapy based on multifunctional single-atom nanosonosensitizers.

Current Advancements in Self-assembling Nanocarriers-Based siRNA Delivery for Cancer Therapy

Different therapeutic practices for treating cancers have significantly evolved to compensate and/or overcome the failures in conventional methodologies. The demonstrated potentiality in completely inhibiting the tumors and in preventing cancer relapse has made nucleic acids therapy (NAT)/gene therapy as an attractive practice. This has been made possible because NAT-based cancer treatments are highly focused on the fundamental mechanisms - i.e., silencing the expression of oncogenic genes responsible for producing abnormal proteins (via messenger RNAs (mRNAs)). However, the future clinical translation of NAT is majorly dependent upon the effective delivery of the exogenous nucleic acids (especially RNAs - e.g., short interfering RNAs (siRNAs) - herein called biological drugs). Moreover, nano-based vehicles (i.e., nanocarriers) are involved in delivering them to prevent degradation and undesired bioaccumulation while enhancing the stability of siRNAs. Herein, we have initially discussed about three major types of self-assembling nanocarriers (liposomes, polymeric nanoparticles and exosomes). Later, we have majorly reviewed recent developments in non-targeted/targeted nanocarriers for delivery of biological drugs (individual/dual) to silence the most important genes/mRNAs accountable for inducing protein abnormality. These proteins include polo-like kinase 1 (PLK1), survivin, vascular endothelial growth factor (VEGF), B-cell lymphoma/leukaemia-2 (Bcl-2) and multi-drug resistance (MDR). Besides, the consequent therapeutic effects on cancer growth, invasion and/or metastasis have also been discussed. Finally, we have comprehensively reviewed the improvements achieved in the cutting-edge cancer therapeutics while delivering siRNAs in combination with clinically approved chemotherapeutic drugs.

Sonodynamic therapy for breast cancer: A literature review

Breast cancer (BC) is a malignant tumor with the highest incidence among women. Surgery, radiotherapy, and chemotherapy are currently used as the first-line methods for treating BC. Sonodynamic therapy (SDT) in combination with sonosensitizers exerts a synergistic effect. The therapeutic effects of SDT depend on factors, such as the intensity, frequency, and duration of ultrasound, and the type and the biological model of sonosensitizer. Current reviews have focused on the possibility of using tumor-seeking sonosensitizers, sometimes in combination with different therapies, such as immunotherapy. This study elucidates the therapeutic mechanism of interaction between SDT and tissue as well as the current progress in medical applications of SDT to BC.

Platinum-Titania Schottky Junction as Nanosonosensitizer, Glucose Scavenger, and Tumor Microenvironment-Modulator for Promoted Cancer Treatment

To date, the construction of heterogeneous interfaces between sonosensitizers and other semiconductors or noble metals has aroused increasing attention, owing to an enhanced interface charge transfer, augmented spin-flip, and attenuated activation energy of oxygen. Here, a smart therapeutic nanoplatform is constructed by surface immobilization of glucose oxidase (GOx) onto a TiO₂@Pt Schottky junction. The sonodynamic therapy (SDT) and starvation therapy (ST) mediated by TiO₂@Pt/GOx (TPG) promote systemic tumor suppression upon hypoxia alleviation in tumor microenvironment. The band gap of TiO₂@Pt is outstandingly decreased to 2.9 eV, in contrast to that of pristine TiO₂. The energy structure optimization enables a more rapid generation of singlet oxygen (¹O₂) and hydroxyl radicals (^•OH) by TiO₂@Pt under ultrasound irradiation, resulting from an enhanced separation of hole-electron pair for redox utilization. The tumorous reactive oxygen species (ROS) accumulation and GOx-mediated glucose depletion facilitate oxidative damage and energy exhaustion of cancer cells, both of which can be tremendously amplified by Pt-catalyzed oxygen self-supply. Importantly, the combinatorial therapy triggers intense immunogenetic cell death, which favors a follow-up suppression of distant tumor and metastasis by evoking antitumor immunity. Collectively, this proof-of-concept paradigm provides an insightful strategy for highly efficient SDT/ST, which possesses good clinical potential for tackling cancer.

Fabrication of TiO2 Spheres and a Visible Light Active α-Fe2O3/TiO2-Rutile/TiO2-Anatase Heterogeneous Photocatalyst from Natural Ilmenite

High-purity (98.8%, TiO₂) rutile nanoparticles were successfully synthesized using ilmenite sand as the initial titanium source. This novel synthesis method was cost-effective and straightforward due to the absence of the traditional gravity, magnetic, electrostatic separation, ball milling, and smelting processes. Synthesized TiO₂ nanoparticles were 99% pure. Also, highly corrosive environmentally hazardous acid leachate generated during the leaching process of ilmenite sand was effectively converted into a highly efficient visible light active photocatalyst. The prepared photocatalyst system consists of anatase-TiO₂/rutile-TiO₂/Fe₂O₃ (TF-800), rutile-TiO₂/Fe₂TiO₅ (TFTO-800), and anatase-TiO₂/Fe₃O₄ (TF-450) nanocomposites, respectively. The pseudo-second-order adsorption rate of the TF-800 ternary nanocomposite was 0.126 g mg^-1 min^-1 in dark conditions, and a 0.044 min^-1 visible light initial photodegradation rate was exhibited. The TFTO-800 binary nanocomposite adsorbed methylene blue (MB) following pseudo-second-order adsorption (0.224 g mg^-1 min^-1) in the dark, and the rate constant for photodegradation of MB in visible light was 0.006 min^-1. The prepared TF-450 nanocomposite did not display excellent adsorptive and photocatalytic performances throughout the experiment period. The synthesized TF-800 and TFTO-800 were able to degrade 93.1 and 49.8% of a 100 mL, 10 ppm MB dye solution within 180 min, respectively.

Ultrasound and nanomaterial: an efficient pair to fight cancer

Ultrasounds are often used in cancer treatment protocols, e.g. to collect tumor tissues in the right location using ultrasound-guided biopsy, to image the region of the tumor using more affordable and easier to use apparatus than MRI and CT, or to ablate tumor tissues using HIFU. The efficacy of these methods can be further improved by combining them with various nano-systems, thus enabling: (i) a better resolution of ultrasound imaging, allowing for example the visualization of angiogenic blood vessels, (ii) the specific tumor targeting of anti-tumor chemotherapeutic drugs or gases attached to or encapsulated in nano-systems and released in a controlled manner in the tumor under ultrasound application, (iii) tumor treatment at tumor site using more moderate heating temperatures than with HIFU. Furthermore, some nano-systems display adjustable sizes, i.e. nanobubbles can grow into micro-bubbles. Such dual size is advantageous since it enables gathering within the same unit the targeting properties of nano bubbles via EPR effect and the enhanced ultrasound contrasting properties of micro bubbles. Interestingly, the way in which nano-systems act against a tumor could in principle also be adjusted by accurately selecting the nano-system among a large choice and by tuning the values of the ultrasound parameters, which can lead, due to their mechanical nature, to specific effects such as cavitation that are usually not observed with purely electromagnetic waves and can potentially help destroying the tumor. This review highlights the clinical potential of these combined treatments that can improve the benefit/risk ratio of current cancer treatments.

Metallic Nanoparticles for the Modulation of Tumor Microenvironment; A New Horizon

Cancer is one of the most critical human challenges which endangers many people’s lives every year with enormous direct and indirect costs worldwide. Unfortunately, despite many advanced treatments used in cancer clinics today, the treatments are deficiently encumbered with many side effects often encountered by clinicians while deploying general methods such as chemotherapy, radiotherapy, surgery, or a combination thereof. Due to their low clinical efficacy, numerous side effects, higher economic costs, and relatively poor acceptance by patients, researchers are striving to find better alternatives for treating this life-threatening complication. As a result, Metal nanoparticles (Metal NPs) have been developed for nearly 2 decades due to their important therapeutic properties. Nanoparticles are quite close in size to biological molecules and can easily penetrate into the cell, so one of the goals of nanotechnology is to mount molecules and drugs on nanoparticles and transfer them to the cell. These NPs are effective as multifunctional nanoplatforms for cancer treatment. They have an advantage over routine drugs in delivering anticancer drugs to a specific location. However, targeting cancer sites while performing anti-cancer treatment can be effective in improving the disease and reducing its complications. Among these, the usage of these nanoparticles (NPs) in photodynamic therapy and sonodynamic therapy are notable. Herein, this review is aimed at investigating the effect and appliances of Metal NPs in the modulation tumor microenvironment which bodes well for the utilization of vast and emerging nanomaterial resources.

The Synthesis of Europium-Doped Calcium Carbonate by an Eco-Method as Free Radical Generator Under Low-Intensity Ultrasonic Irradiation for Body Sculpture

Body sculpture is a common method to remove excessive fat. The diet and exercise are the first suggestion to keep body shape; however, those are difficult to keep adherence. Ultrasound has been developed for fat ablation; however, it could only serve as the side treatment along with liposuction. In the study, a sonosensitizer of europium-doped calcium carbonate (CaCO₃: Eu) would be synthesized by an eco-method and combined with low-intensity ultrasound for lipolysis. The crystal structure of CaCO₃: Eu was identified by x-ray diffractometer (XRD). The morphology of CaCO₃: Eu was analyzed by scanning electron microscope (SEM). The chemical composition of CaCO₃: Eu was evaluated by energy-dispersed spectrophotometer (EDS) and inductively coupled plasma mass spectrometer (ICP-MS). The electronic diffraction pattern was to further check crystal structure of the synthesized individual grain by transmission electron microscope (TEM). The particle size was determined by Zeta-sizer. Water-soluble tetrazolium salt (WST-1) were used to evaluate the cell viability. Chloromethyl-2′,7′-dichlorofluorescein diacetate (CM-H₂DCFDA) and live/dead stain were used to evaluate feasibility in vitro. SD-rat was used to evaluate the safety and efficacy in vivo. The results showed that CaCO₃: Eu had good biocompatibility and could produce reactive oxygen species (ROS) after treated with low-intensity ultrasound. After 4-weeks, the CaCO₃: Eu exposed to ultrasound irradiation on SD rats could significantly decrease body weight, waistline, and subcutaneous adipose tissue. We believe that ROS from sonoluminescence, CO₂-bomb and locally increasing Ca²⁺ level would be three major mechanisms to remove away adipo-tissue and inhibit adipogenesis. We could say that the combination of the CaCO₃: Eu and low-intensity ultrasound would be a non-invasive treatment for the body sculpture.

Recent ultrasound advancements for the manipulation of nanobiomaterials and nanoformulations for drug delivery

Recent advances in ultrasound (US) have shown its great potential in biomedical applications as diagnostic and therapeutic tools. The coupling of US-assisted drug delivery systems with nanobiomaterials possessing tailor-made functions has been shown to remove the limitations of conventional drug delivery systems. The low-frequency US has significantly enhanced the targeted drug delivery effect and efficacy, reducing limitations posed by conventional treatments such as a limited therapeutic window. The acoustic cavitation effect induced by the US-mediated microbubbles (MBs) has been reported to replace drugs in certain acute diseases such as ischemic stroke. This review briefly discusses the US principles, with particular attention to the recent advancements in drug delivery applications. Furthermore, US-assisted drug delivery coupled with nanobiomaterials to treat different diseases (cancer, neurodegenerative disease, diabetes, thrombosis, and COVID-19) are discussed in detail. Finally, this review covers the future perspectives and challenges on the applications of US-mediated nanobiomaterials.

Multifunctional Composite Nanosystems for Precise/Enhanced Sonodynamic Oxidative Tumor Treatment

Ultrasound-activated therapies have been regarded as the efficient strategy for tumor treatment, among which sonosensitizer-enabled sonodynamic oxidative tumor therapy features intrinsic advantages as compared to other exogenous trigger-activated dynamic therapies. Nanomedicine-based nanosonosensitizer design has been extensively explored for improving the therapeutic efficacy of sonodynamic therapy (SDT) of tumor. This review focuses on solving two specific issues, i.e., precise and enhanced sonodynamic oxidative tumor treatment, by rationally designing and engineering multifunctional composite nanosonosensitizers. This multifunctional design can augment the therapeutic efficacy of SDT against tumor by either improving the production of reactive oxygen species or inducing the synergistic effect of SDT-based combinatorial therapies. Especially, this multifunctional design is also capable of endowing the nanosonosensitizer with bioimaging functionality, which can effectively guide and monitor the therapeutic procedure of the introduced sonodynamic oxidative tumor treatment. The design principles, underlying material chemistry for constructing multifunctional composite nanosonosensitizers, intrinsic synergistic mechanism, and bioimaging guided/monitored precise SDT are summarized and discussed in detail with the most representative paradigms. Finally, the existing critical issues, available challenges, and potential future developments of this research area are also discussed for promoting the further clinical translations of these multifunctional composite nanosonosensitizers in SDT-based tumor treatment.

Titanium and Iron Oxide Nanoparticles for Cancer Therapy: Surface Chemistry and Biological Implications

Currently, cancer is among the most challenging diseases due to its ability to continuously evolve into a more complex muldimentional system, in addition to its high capability to spread to other organs and tissues. In this context, the relevance of nanobiomaterials (NBMs) for the development of new more effective and less harmful treatments is increasing. NBMs provide the possibility of combining several functionalities on a single system, expectedly in a synergic way, to better perform the treatment and cure. However, the control of properties such as colloidal stability, circulation time, pharmacokinetics, and biodistribution, assuring the concentration in specific target tissues and organs, while keeping all desired properties, tends to be dependent on subtle changes in surface chemistry. Hence, the behavior of such materials in different media/environments is of uttermost relevance and concern since it can compromise their efficiency and safety on application. Given the bright perspectives, many efforts have been focused on the development of nanomaterials fulfilling the requirements for real application. These include robust and reproducible preparation methods to avoid aggregation while preserving the interaction properties. The possible impact of nanomaterials in different forms of diagnosis and therapy has been demonstrated in the past few years, given the perspectives on how revolutionary they can be in medicine and health. Considering the high biocompatibility and suitability, this review is focused on titanium dioxide– and iron oxide–based nanoagents highlighting the current trends and main advancements in the research for cancer therapies. The effects of phenomena, such as aggregation and agglomeration, the formation of the corona layer, and how they can compromise relevant properties of nanomaterials and their potential applicability, are also addressed. In short, this review summarizes the current understanding and perspectives on such smart nanobiomaterials for diagnostics, treatment, and theranostics of diseases.

Controlled killing of human cervical cancer cells by combined action of blue light and C-doped TiO2 nanoparticles

In this study, C-doped TiO₂ nanoparticles (C-TiO₂) were prepared and tested as a photosensitizer for visible-light-driven photodynamic therapy against cervical cancer cells (HeLa). X-ray diffraction and Transmission Electron Microscopy confirmed the anatase form of nanoparticles, spherical shape, and size distribution from 5 to 15 nm. Ultraviolet-visible light spectroscopy showed that C doping of TiO₂ enhances the optical absorption in the visible light range caused by a bandgap narrowing. The photo-cytotoxic activity of C-TiO₂ was investigated in vitro against HeLa cells. The lack of dark cytotoxicity indicates good biocompatibility of C-TiO₂. In contrast, a combination with blue light significantly reduced the survival of HeLa cells: illumination only decreased cell viability by 30% (15 min of illumination, 120 µW power), and 60% when HeLa cells were preincubated with C-TiO₂. We have also confirmed blue light-induced C-TiO₂-catalyzed generation of reactive oxygen species in vitro and intracellularly. Oxidative stress triggered by C-TiO₂/blue light was the leading cause of HeLa cell death. Fluorescent labeling of treated HeLa cells showed distinct morphological changes after the C-TiO₂/blue light treatment. Unlike blue light illumination, which caused the appearance of large necrotic cells with deformed nuclei, cytoplasm swelling, and membrane blebbing, a combination of C-TiO₂/blue light leads to controlled cell death, thus providing a better outcome of local anticancer therapy.

Synergistic biocidal effects of metal oxide nanoparticles-assisted ultrasound irradiation: Antimicrobial sonodynamic therapy against Streptococcus mutans biofilms

BACKGROUND

Antimicrobial sonodynamic therapy (aSDT) is an adjunctive modality, which uses ultrasound irradiation to kill microbial cells by the activation of a sonosensitizer. The aim of this study was to evaluated the synergistic biocidal effects of zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO₂ NPs) as the metal oxide nanoparticles (MONPs)-assisted ultrasound irradiation against Streptococcus mutans biofilms.

MATERIALS AND METHODS

Following preparation and characterization of MONPs, cellular uptake and generation of intracellular reactive oxygen species (ROS) were assessed. After determination of the sub-significant reduction (SSR) doses of ZnO NPs, TiO₂ NPs, ZnO/TiO₂ NPs, and ultrasound intensity against S. mutans, anti-biofilm effects of aSDT were assessed using colorimetric assay, plate counting, and field emission scanning electron microscope (FESEM) analysis. Also, the metabolic activity of S. mutans and the expression levels of glucosyltransferase B (gtfB) as a main virulence factor of S. mutans were evaluated by XTT assay and quantitative real-time polymerase chain reaction following ZnO/TiO₂ NPs^SSR- mediated aSDT.

RESULTS

The finding of this study showed that an incubation time of 5 min was sufficient to achieve maximal uptake of MONPs. The ROS production following aSDT using ZnO NPs, TiO₂ NPs, and ZnO/TiO₂ NPs were ~ 4.1-, 5.6-, and 11.7-fold increase, respectively. The dose-dependent reduction in cell viability of S. mutans was revealed by increasing the concentrations of ZnO NPs, TiO₂ NPs, ZnO/TiO₂, as well as ultrasound intensities. According to the data, 1.5 µg/mL, 3.1 µg/mL, 25 µg/mL, and 0.75 W/cm² were considered as the SSR doses of ZnO/TiO₂ NPs, ZnO NPs, TiO₂ NPs, and ultrasound intensity, respectively (P>0.05). ZnO/TiO₂ NPs^SSR-mediated aSDT showed a significantly higher biofilm inhibitory activity than the other treatment groups (P<0.05). Based on the FE-SEM analysis, aSDT based on the ZnO/TiO₂ NPs^SSR had a strong anti-biofilm effect against preformed biofilms of S. mutans on the enamel slabs. Also, the metabolic activity of S. mutans and the expression levels of gtfB were significantly decreased to 85.5% and 12.3-fold, respectively following ZnO/TiO₂ NPs^SSR-mediated aSDT (P<0.05). No considerable difference was observed in anti-biofilm activity between ZnO/TiO₂ NPs^SSR- mediated aSDT and 0.2% CHX (P>0.05).

CONCLUSION

The results revealed anti-metabolic and anti-biofilm potential activities of ZnO/TiO₂ NPs-mediated aSDT against S. mutans with the highest cellular uptake and ROS generation.

Reactive Oxygen Species-Based Nanomaterials for Cancer Therapy

Nanotechnology advances in cancer therapy applications have led to the development of nanomaterials that generate cytotoxic reactive oxygen species (ROS) specifically in tumor cells. ROS act as a double-edged sword, as they can promote tumorigenesis and proliferation but also trigger cell death by enhancing intracellular oxidative stress. Various nanomaterials function by increasing ROS production in tumor cells and thereby disturbing their redox balance, leading to lipid peroxidation, and oxidative damage of DNA and proteins. In this review, we outline these mechanisms, summarize recent progress in ROS-based nanomaterials, including metal-based nanoparticles, organic nanomaterials, and chemotherapy drug-loaded nanoplatforms, and highlight their biomedical applications in cancer therapy as drug delivery systems (DDSs) or in combination with chemodynamic therapy (CDT), photodynamic therapy (PDT), or sonodynamic therapy (SDT). Finally, we discuss the advantages and limitations of current ROS-mediated nanomaterials used in cancer therapy and speculate on the future progress of this nanotechnology for oncological applications.

To Synthesize Hydroxyapatite by Modified Low Temperature Method Loaded with Bletilla striata Polysaccharide as Antioxidant for the Prevention of Sarcopenia by Intramuscular Administration

Oxidative stress has been suggested as an important factor in the progress of sarcopenia. The current treatments for sarcopenia have the disadvantages of insufficient effect or daily administration. Therefore, an alternative for effective, safety and long-term treatment may be a solution for unmet needs. Bletilla striata polysaccharide has been reported to have anti-oxidative and anti-inflammatory properties. In this study, we used Bletilla striata polysaccharide (BSP) combined with hydroxyapatite, a carrier. We hypothesized that the resulting combination (BSP-HAP) is a good formula for the controlled release of BSP via intramuscular (IM) administration, so as to prevent the worsening of presarcopenia or even recover from the early stage of the illness. In this research, BSP-HAP was synthesized by a modified low temperature co-precipitation process that would be beneficial for BSP loading. By conducting DCFDA, WST-1 and the Live/Dead assay, BSP-HAP is shown to be a biocompatible material which may release BSP by cells through the endocytosis pathway. Animal studies revealed that the rats treated with BSP-HAP could effectively recover muscle endurance, grip strength or fat/lean mass ratio from lipopolysaccharide (LPS)-induced sarcopenia. This study shows BSP delivered by BSP-HAP system has potential for application in the treatment and prevention of sarcopenia in the future.

Unmodified Titanium Dioxide Nanoparticles as a Potential Contrast Agent in Photon Emission Computed Tomography

Highly crystalline titanium dioxide nanoparticles (TiO2-NPs) are synthesized via a simple hydrothermal technique. After structural and compositional analysis, the as-synthesized unmodified TiO2-NPs are tested for improvement in two modes of kilovoltage radiation therapy and single-photon emission computed tomography (SPECT)/computed tomography (CT). Our results show that the unmodified TiO2-NPs provide an observable enhancement in CT scan image contrast ranging from 0 ± 3 HU (without NPs) to 283.7 ± 3 HU (0.23 g/mL). TiO2-NPs has excellent biocompatibility, selective uptake at target sites, and reduced toxicity. The unmodified TiO2-NPs as a contrast agent can significantly improve the existing methods of diagnosing and treating cancer.

Biomedical Applications of Reactive Oxygen Species Generation by Metal Nanoparticles

The design, synthesis and characterization of new nanomaterials represents one of the most dynamic and transversal aspects of nanotechnology applications in the biomedical field. New synthetic and engineering improvements allow the design of a wide range of biocompatible nanostructured materials (NSMs) and nanoparticles (NPs) which, with or without additional chemical and/or biomolecular surface modifications, are more frequently employed in applications for successful diagnostic, drug delivery and therapeutic procedures. Metal-based nanoparticles (MNPs) including metal NPs, metal oxide NPs, quantum dots (QDs) and magnetic NPs, thanks to their physical and chemical properties have gained much traction for their functional use in biomedicine. In this review it is highlighted how the generation of reactive oxygen species (ROS), which in many respects could be considered a negative aspect of the interaction of MNPs with biological matter, may be a surprising nanotechnology weapon. From the exchange of knowledge between branches such as materials science, nanotechnology, engineering, biochemistry and medicine, researchers and clinicians are setting and standardizing treatments by tuning ROS production to induce cancer or microbial cell death.