A hydrogenated black TiO2 coating with excellent effects for photothermal therapy of bone tumor and bone regeneration

Engineering multifunctional surface topography to regulate multiple biological responses

Surface topography or curvature plays a crucial role in regulating cell behavior, influencing processes such as adhesion, proliferation, and gene expression. Recent advancements in nano- and micro-fabrication techniques have enabled the development of biomimetic systems that mimic native extracellular matrix (ECM) structures, providing new insights into cell-adhesion mechanisms, mechanotransduction, and cell-environment interactions. This review examines the diverse applications of engineered topographies across multiple domains, including antibacterial surfaces, immunomodulatory devices, tissue engineering scaffolds, and cancer therapies. It highlights how nanoscale features like nanopillars and nanospikes exhibit bactericidal properties, while many microscale patterns can direct stem cell differentiation and modulate immune cell responses. Furthermore, we discuss the interdisciplinary use of topography for combined applications, such as the simultaneous regulation of immune and tissue cells in 2D and 3D environments. Despite significant advances, key knowledge gaps remain, particularly regarding the effects of topographical cues on multicellular interactions and dynamic 3D contexts. This review summarizes current fabrication methods, explores specific and interdisciplinary applications, and proposes future research directions to enhance the design and utility of topographically patterned biomaterials in clinical and experimental settings.

Bone scaffolds-based localized drugs delivery for osteosarcoma: current status and future perspective

A common malignant bone neoplasm in teenagers is Osteosarcoma. Chemotherapy, surgical therapy, and radiation therapy together comprise the usual clinical course of treatment for Osteosarcoma. While Osteosarcoma and other bone tumors are typically treated surgically, however, surgical resection frequently fails to completely eradicate tumors, and in turn becomes the primary reason for postoperative recurrence and metastasis, ultimately leading to a high rate of mortality. Patients still require radiation and/or chemotherapy after surgery to stop the spread of the tumor and its metastases, and both treatments have an adverse influence on the body's organ systems. In the postoperative management of osteosarcoma, bone scaffolds can load cargos (growth factors or drugs) and function as drug delivery systems (DDSs). This review describes the different kinds of bone scaffolds that are currently available and highlights key studies that use scaffolds as DDSs for the treatment of osteosarcomas. The discussion also includes difficulties and perspectives regarding the use of scaffold-based DDSs. The study may serve as a source for outlining efficient and secure postoperative osteosarcoma treatment plans.

Exploring the frontiers: The potential and challenges of bioactive scaffolds in osteosarcoma treatment and bone regeneration

The standard treatment for osteosarcoma combines surgery with chemotherapy, yet it is fraught with challenges such as postoperative tumor recurrence and chemotherapy-induced side effects. Additionally, bone defects after surgery often surpass the body's regenerative ability, affecting patient recovery. Bioengineering offers a novel approach through the use of bioactive scaffolds crafted from metals, ceramics, and hydrogels for bone defect repair. However, these scaffolds are typically devoid of antitumor properties, necessitating the integration of therapeutic agents. The development of a multifunctional therapeutic platform incorporating chemotherapeutic drugs, photothermal agents (PTAs), photosensitizers (PIs), sound sensitizers (SSs), magnetic thermotherapeutic agents (MTAs), and naturally occurring antitumor compounds addresses this limitation. This platform is engineered to target osteosarcoma cells while also facilitating bone tissue repair and regeneration. This review synthesizes recent advancements in integrated bioactive scaffolds (IBSs), underscoring their dual role in combating osteosarcoma and enhancing bone regeneration. We also examine the current limitations of IBSs and propose future research trajectories to overcome these hurdles.

An Amorphous-to-Anatase Phase Transition Study of TiO2 Nanotubes by Temperature-Dependent Synchrotron-Based In Situ X-ray Diffraction

TiO2 nanotubes (NTs) with amorphous and crystalline structures have attracted interest due to their wide range of applications, particularly black TiO2, which addresses the limitations of conventional TiO2 (a wide band gap of 3.0-3.2 eV). Understanding the amorphous-to-anatase phase transition is crucial for phase control of crystalline TiO2. This study investigates the size-dependent phase transition behavior of TiO2 and black TiO2 NTs using temperature-dependent synchrotron-based X-ray diffraction. Thermal treatments reveal that phase transitions occur in the ranges of 210-240 °C for normal NTs and 270-300 °C for black NTs. The onset temperature and crystallization growth are dependent on size, especially NT length, at least in the system under investigation. We observe anisotropic crystallization in quantum confinement, with the unit cell undergoing compression in the a-axis and expansion in the c-axis during crystallization. The longest black NTs (BV50T4) show a significant difference in the c/a ratio. Defects, such as oxygen vacancies, localize on specific NT planes.

Innovative Biomaterials for Bone Tumor Treatment and Regeneration: Tackling Postoperative Challenges and Charting the Path Forward

Surgical resection of bone tumors is the primary approach employed in the treatment of bone cancer. Simultaneously, perioperative interventions, particularly postoperative adjuvant anticancer strategies, play a crucial role in achieving satisfactory therapeutic outcomes. However, the occurrence of postoperative bone tumor recurrence, metastasis, extensive bone defects, and infection are significant risks that can result in unfavorable prognoses or even treatment failure. In recent years, there has been significant progress in the development of biomaterials, leading to the emergence of new treatment options for bone tumor therapy and bone regeneration. This progress report aims to comprehensively analyze the strategic development of unique therapeutic biomaterials with inherent healing properties and bioactive capabilities for bone tissue regeneration. These composite biomaterials, classified into metallic, inorganic non-metallic, and organic types, are thoroughly investigated for their responses to external stimuli such as light or magnetic fields, internal interventions including chemotherapy or catalytic therapy, and combination therapy, as well as their role in bone regeneration. Additionally, an overview of self-healing materials for osteogenesis is provided and their potential applications in combating osteosarcoma and promoting bone formation are explored. Furthermore, the safety concerns of integrated materials and current limitations are addressed, while also discussing the challenges and future prospects.

Postoperative tumor treatment strategies: From basic research to clinical therapy

Despite progression in advanced treatments for malignant tumors, surgery remains the primary treatment intervention, which removes a large portion of firm tumor tissues; however, the postoperative phase poses a possible risk for provincial tumor recurrence and metastasis. Consequently, the prevention of tumor recurrence and metastasis has attracted research attention. In this review, we summarized the postoperative treatment strategies for various tumors from both basic research and clinical perspectives. We delineated the underlying factors contributing to the recurrence of malignant tumors with a substantial prevalence rate, related molecular mechanisms of tumor recurrence post‐surgery, and related means of monitoring recurrence and metastasis after surgery. Furthermore, we described relevant therapeutic approaches for postoperative tumor recurrence, including chemotherapy, radiation therapy, immunotherapy, targeted therapy, and photodynamic therapy. This review focused on the emerging technologies used for postoperative tumor treatment in recent years in terms of functional classification, including the prevention of postoperative tumor recurrence, functional reconstruction, and monitoring of recurrence. Finally, we discussed the future development and deficiencies of postoperative tumor therapy. To understand postoperative treatment strategies for tumors from clinical treatment and basic research and further guide the research directions for postoperative tumors.

Novel Photothermal Graphene-Based Hydrogels in Biomedical Applications

In the last decade, photothermal therapy (PTT) has attracted tremendous attention because it is non-invasive, shows high efficiency and antibacterial activity, and minimizes drug side effects. Previous studies demonstrated that PTT can effectively inhibit the growth of bacteria and promotes cell proliferation, accelerating wound healing and tissue regeneration. Among different NIR-responsive biomaterials, graphene-based hydrogels with photothermal properties are considered as the best candidates for biomedical applications, due to their excellent properties. This review summarizes the current advances in the development of innovative graphene-based hydrogels for PTT-based biomedical applications. Also, the information about photothermal properties and the potential applications of graphene-based hydrogels in biomedical therapies are provided. These findings provide a great potential for supporting their applications in photothermal biomedicine.

Smart stimuli-responsive strategies for titanium implant functionalization in bone regeneration and therapeutics

With the increasing and aging of global population, there is a dramatic rise in the demand for implants or substitutes to rehabilitate bone-related disorders which can considerably decrease quality of life and even endanger lives. Though titanium and its alloys have been applied as the mainstream material to fabricate implants for load-bearing bone defect restoration or temporary internal fixation devices for bone fractures, it is far from rare to encounter failed cases in clinical practice, particularly with pathological factors involved. In recent years, smart stimuli-responsive (SSR) strategies have been conducted to functionalize titanium implants to improve bone regeneration in pathological conditions, such as bacterial infection, chronic inflammation, tumor and diabetes mellitus, etc. SSR implants can exert on-demand therapeutic and/or pro-regenerative effects in response to externally applied stimuli (such as photostimulation, magnetic field, electrical and ultrasound stimulation) or internal pathology-related microenvironment changes (such as decreased pH value, specific enzyme secreted by bacterial and excessive production of reactive oxygen species). This review summarizes recent progress on the material design and fabrication, responsive mechanisms, and in vitro and in vivo evaluations for versatile clinical applications of SSR titanium implants. In addition, currently existing limitations and challenges and further prospective directions of these strategies are also discussed.

Current status and prospect of ZIF-based materials for breast cancer treatment

Breast cancer, one of the three most life-threatening cancers in modern times, must be explored for treatments with low side effects and practical efficacy. Metal organic framework materials (MOFs) is made by metal ions as the center for point and organic ligands as a bridge connecting a new type of porous nano-materials, among them, the zinc base zeolite imidazole skeleton material series (ZIFs) because of its excellent biocompatibility and pH slow controlled release ability, is widely used in the tumor microenvironment in basic research and achieved remarkable curative effect. Inspired by this, in this review, we focus on the recent research progress on the application of ZIFs in the treatment of breast cancer, mainly studying the structure of ZIFs such as ZIF-8, ZIF-90 and ZIF-67 and their application in novel therapies for breast cancer treatment, such as targeted drug delivery, photothermal therapy, immunotherapy and gene therapy.We will more fully demonstrate the potential of zif in breast cancer treatment, hoping to provide an avenue for exploring breast cancer treatment.

Phototherapy techniques for the management of musculoskeletal disorders: strategies and recent advances

Musculoskeletal disorders (MSDs), which include a range of pathologies affecting bones, cartilage, muscles, tendons, and ligaments, account for a significant portion of the global burden of disease. While pharmaceutical and surgical interventions represent conventional approaches for treating MSDs, their efficacy is constrained and frequently accompanied by adverse reactions. Considering the rising incidence of MSDs, there is an urgent demand for effective treatment modalities to alter the current landscape. Phototherapy, as a controllable and non-invasive technique, has been shown to directly regulate bone, cartilage, and muscle regeneration by modulating cellular behavior. Moreover, phototherapy presents controlled ablation of tumor cells, bacteria, and aberrantly activated inflammatory cells, demonstrating therapeutic potential in conditions such as bone tumors, bone infection, and arthritis. By constructing light-responsive nanosystems, controlled drug delivery can be achieved to enable precise treatment of MSDs. Notably, various phototherapy nanoplatforms with integrated imaging capabilities have been utilized for early diagnosis, guided therapy, and prognostic assessment of MSDs, further improving the management of these disorders. This review provides a comprehensive overview of the strategies and recent advances in the application of phototherapy for the treatment of MSDs, discusses the challenges and prospects of phototherapy, and aims to promote further research and application of phototherapy techniques.

Oxygen-Deficient Bioceramics: Combination of Diagnosis, Therapy, and Regeneration

The journey of ceramics in medicine has been synchronized with an evolution from the first generation-alumina, zirconia, etc.-to the third -3D scaffolds. There is an up-and-coming member called oxygen-deficient or colored bioceramics, which have recently found their way through biomedical applications. The oxygen vacancy steers the light absorption toward visible and near infrared regions, making the colored bioceramics multifunctional-therapeutic, diagnostic, and regenerative. Oxygen-deficient bioceramics are capable of turning light into heat and reactive oxygen species for photothermal and photodynamic therapies, respectively, and concomitantly yield infrared and photoacoustic images. Different types of oxygen-deficient bioceramics have been recently developed through various synthesis routes. Some of them like TiO2- x , MoO3- x , and WOx have been more investigated for biomedical applications, whereas the rest have yet to be scrutinized. The most prominent advantage of these bioceramics over the other biomaterials is their multifunctionality endowed with a change in the microstructure. There are some challenges ahead of this category discussed at the end of the present review. By shedding light on this recently born bioceramics subcategory, it is believed that the field will undergo a big step further as these platforms are naturally multifunctional.

A Review on Nano Ti-Based Oxides for Dark and Photocatalysis: From Photoinduced Processes to Bioimplant Applications

Catalysis on TiO₂ nanomaterials in the presence of H₂O and oxygen plays a crucial role in the advancement of many different fields, such as clean energy technologies, catalysis, disinfection, and bioimplants. Photocatalysis on TiO₂ nanomaterials is well-established and has advanced in the last decades in terms of the understanding of its underlying principles and improvement of its efficiency. Meanwhile, the increasing complexity of modern scientific challenges in disinfection and bioimplants requires a profound mechanistic understanding of both residual and dark catalysis. Here, an overview of the progress made in TiO₂ catalysis is given both in the presence and absence of light. It begins with the mechanisms involving reactive oxygen species (ROS) in TiO₂ photocatalysis. This is followed by improvements in their photocatalytic efficiency due to their nanomorphology and states by enhancing charge separation and increasing light harvesting. A subsection on black TiO₂ nanomaterials and their interesting properties and physics is also included. Progress in residual catalysis and dark catalysis on TiO₂ are then presented. Safety, microbicidal effect, and studies on Ti-oxides for bioimplants are also presented. Finally, conclusions and future perspectives in light of disinfection and bioimplant application are given.

Synthetic biodegradable polymer materials in the repair of tumor-associated bone defects

The repair and reconstruction of bone defects and the inhibition of local tumor recurrence are two common problems in bone surgery. The rapid development of biomedicine, clinical medicine, and material science has promoted the research and development of synthetic degradable polymer anti-tumor bone repair materials. Compared with natural polymer materials, synthetic polymer materials have machinable mechanical properties, highly controllable degradation properties, and uniform structure, which has attracted more attention from researchers. In addition, adopting new technologies is an effective strategy for developing new bone repair materials. The application of nanotechnology, 3D printing technology, and genetic engineering technology is beneficial to modify the performance of materials. Photothermal therapy, magnetothermal therapy, and anti-tumor drug delivery may provide new directions for the research and development of anti-tumor bone repair materials. This review focuses on recent advances in synthetic biodegradable polymer bone repair materials and their antitumor properties.

Recent advances in hydrogels-based osteosarcoma therapy

Osteosarcoma (OS), as a typical kind of bone tumors, has a high incidence among adolescents. Traditional tumor eradication avenues for OS such as chemotherapy, surgical therapy and radiation therapy usually have their own drawbacks including recurrence and metastasis. In addition, another serious issue in the treatment of OS is bone repair because the bone after tumor invasion usually has difficulty in repairing itself. Hydrogels, as a synthetic or natural platform with a porous three-dimensional structure, can be applied as desirable platforms for OS treatment. They can not only be used as carriers for tumor therapeutic drugs but mimic the extracellular matrix for the growth and differentiation of mesenchymal stem cells (MSCs), thus providing tumor treatment and enhancing bone regeneration at the same time. This review focuses the application of hydrogels in OS suppression and bone regeneration, and give some suggests on future development.

Rapid mineralization of graphene-based 3D porous scaffolds by semi-dry electrodeposition for photothermal treatment of tumor-induced bone defects

Graphene-based three-dimensional (3D) porous scaffolds have been extensively investigated in the photothermal treatment of tumor-induced bone defects due to their photothermal and osteogenic capacity. However, scaffold processing destroys conjugated graphene structure and reduces its photothermal conversion efficiency. In this study, a graphene-based 3D scaffold (GS) with intact conjugated structure was prepared by chemical vapor deposition (CVD). GS was rapidly mineralized biomimetically by a newly developed semi-dry electrochemical deposition method to form a hydroxyapatite (HA) incorporated graphene scaffold (HA-GS). The simulation of the charged particle dynamics provides a better understanding of the mechanism of semi-dry electrodeposition. This scaffold exhibits high photothermal sensitivity that generates sufficient thermal energy for photothermal therapy even under near-infrared irradiation (980 nm) with extremely low power density (0.2 W/cm²). Moreover, osteogenic activity was improved by HA-GS compared with GS. Compared with the blank GS, the HA-GS scaffold deposited with HA also showed regulation of macrophage-derived chemokine (MDC) and remodeled the immune microenvironment of the wound after photothermal therapy. In vivo experiments further verified that HA-GS can ablate osteosarcoma through a photothermal effect. These results suggest that the as-prepared HA-GS may be adopted as a promising multifunctional bone scaffold against tumor-induced bone defect. STATEMENT OF SIGNIFICANCE: The hydroxyapatite (HA) incorporated graphene scaffold (HA-GS) scaffold was prepared by semi-dry electrodeposition first time. The prepared HA-GS has a high photothermal conversion efficiency (it can rise to 48 ^oC under the 5 min irradiation of 980 nm near-infrared laser at 0.2 W/cm²). The mineralized layer prepared by semi-dry electrodeposition is not only osteoinductive, but also reduces the inflammatory response after photothermal therapy. This modulates the immune microenvironment at the bone tumor invasion site, thereby promoting defect repair.

Photothermal-Controlled Release of IL-4 in IL-4/PDA-Immobilized Black Titanium Dioxide (TiO2) Nanotubes Surface to Enhance Osseointegration: An In Vivo Study

Host immune response has gradually been accepted as a critical factor in achieving successful implant osseointegration. The aim of this study is to create a favorable immune microenvironment by the dominant release of IL-4 during the initial few days after implant insertion to mitigate early inflammatory reactions and facilitate osseointegration. Herein, the B-TNT/PDA/IL-4 substrate was established by immobilizing an interleukin-4 (IL-4)/polydopamine (PDA) coating on a black TiO₂ nanotube (B-TNT) surface, achieving on-demand IL-4 release under near infrared (NIR) irradiation. Gene Ontology (GO) enrichment analyses based on high-throughput DNA microarray data revealed that IL-4 addition inhibited osteoclast differentiation and function. Animal experiment results suggested that the B-TNT/PDA/IL-4+Laser substrate induced the least inflammatory, tartrate-resistant acid phosphatase, inducible nitric oxide synthase and the most CD163 positive cells, compared to the Ti group at 7 days post-implantation. In addition, 28 days post-implantation, micro-computed tomography results showed the highest bone volume/total volume, trabecular thickness, trabecular number and the lowest trabecular separation, while Hematoxylin-eosin and Masson-trichrome staining revealed the largest amount of new bone formation for the B-TNT/PDA/IL-4+Laser group. This study revealed the osteoimmunoregulatory function of the novel B-TNT/PDA/IL-4 surface by photothermal release of IL-4 at an early period post-implantation, thus paving a new way for dental implant surface modification.

Hope for bone regeneration: The versatility of iron oxide nanoparticles

Although bone tissue has the ability to heal itself, beyond a certain point, bone defects cannot rebuild themselves, and the challenge is how to promote bone tissue regeneration. Iron oxide nanoparticles (IONPs) are a magnetic material because of their excellent properties, which enable them to play an active role in bone regeneration. This paper reviews the application of IONPs in bone tissue regeneration in recent years, and outlines the mechanisms of IONPs in bone tissue regeneration in detail based on the physicochemical properties, structural characteristics and safety of IONPs. In addition, a bibliometric approach has been used to analyze the hot spots and trends in the field in order to identify future directions. The results demonstrate that IONPs are increasingly being investigated in bone regeneration, from the initial use as magnetic resonance imaging (MRI) contrast agents to later drug delivery vehicles, cell labeling, and now in combination with stem cells (SCs) composite scaffolds. In conclusion, based on the current research and development trends, it is more inclined to be used in bone tissue engineering, scaffolds, and composite scaffolds.

Electroactive functional microenvironments from bioactive polymers: A new strategy to address cancer

The present work reports on a new approach based on electroactive microenvironments to mitigate skeletal muscle cancer. For that, piezoelectric films based on poly(vinylidene fluoride) have been applied to evaluate the influence of mechano- and/or electrical stimuli on rhabdomyosarcoma (RMS) proliferation. Human embryonal rhabdomyosarcoma (RD) cells were cultured on PVDF pristine films with different surface charge (non-poled, poled+ and poled-) and magnetic composites (10% and 20% Fe₃O₄, and 20% CFO filler content) to allow magneto-mechanical and magnetoelectrical stimulation films. Electrospun PVDF pristine (oriented and randomly) and magnetic (10% Fe₃O₄) fiber mats were also evaluated to take into consideration the morphology effect on cell response. It was found that the mechanical stimuli enhance RMS proliferation whereas the mechano-electrical decreases it. It was also verified that the RD cells proliferate better on randomly oriented fibers, whereas myoblast cells do it better in oriented ones. The obtained results confirm that electroactive microenvironments can be used to develop novel and effective approaches to deal with RMS cancer, that can be extrapolated to others cancer types.

Bone tumors effective therapy through functionalized hydrogels: current developments and future expectations

Primary bone tumors especially, sarcomas affect adolescents the most because it originates from osteoblasts cells responsible for bone growth. Chemotherapy, surgery, and radiation therapy are the most often used clinical treatments. Regrettably, surgical resection frequently fails to entirely eradicate the tumor, which is the primary cause of metastasis and postoperative recurrence, leading to a high death rate. Additionally, bone tumors frequently penetrate significant regions of bone, rendering them incapable of self-repair, and impairing patients' quality of life. As a result, treating bone tumors and regenerating bone in the clinic is difficult. In recent decades, numerous sorts of alternative therapy approaches have been investigated due to a lack of approved treatments. Among the novel therapeutic approaches, hydrogel-based anticancer therapy has cleared the way for the development of new targeted techniques for treating bone cancer and bone regeneration. They include strategies such as co-delivery of several drug payloads, enhancing their biodistribution and transport capabilities, normalizing accumulation, and optimizing drug release profiles to decrease the limitations of current therapy. This review discusses current advances in functionalized hydrogels to develop a new technique for treating bone tumors by reducing postoperative tumor recurrence and promoting tissue repair.

Titanium Implants and Local Drug Delivery Systems Become Mutual Promoters in Orthopedic Clinics

Titanium implants have always been regarded as one of the gold standard treatments for orthopedic applications, but they still face challenges such as pain, bacterial infections, insufficient osseointegration, immune rejection, and difficulty in personalizing treatment in the clinic. These challenges may lead to the patients having to undergo a painful second operation, along with increased economic burden, but the use of drugs is actively solving these problems. The use of systemic drug delivery systems through oral, intravenous, and intramuscular injection of various drugs with different pharmacological properties has effectively reduced the levels of inflammation, lowered the risk of endophytic bacterial infection, and regulated the progress of bone tumor cells, processing and regulating the balance of bone metabolism around the titanium implants. However, due to the limitations of systemic drug delivery systems-such as pharmacokinetics, and the characteristics of bone tissue in the event of different forms of trauma or disease-sometimes the expected effect cannot be achieved. Meanwhile, titanium implants loaded with drugs for local administration have gradually attracted the attention of many researchers. This article reviews the latest developments in local drug delivery systems in recent years, detailing how various types of drugs cooperate with titanium implants to enhance antibacterial, antitumor, and osseointegration effects. Additionally, we summarize the improved technology of titanium implants for drug loading and the control of drug release, along with molecular mechanisms of bone regeneration and vascularization. Finally, we lay out some future prospects in this field.

3D Printing of Black Bioceramic Scaffolds with Micro/Nanostructure for Bone Tumor-Induced Tissue Therapy

It is common to improve the relevant performance in the field of energy storage materials or catalytic materials by regulating the number of defects. However, there are few studies on the biomaterials containing defects for tissue engineering. Herein, a new type of defect-rich scaffolds, black akermanite (B-AKT) bioceramic scaffolds with micro/nanostructure, the thickness of which is from 0.14 to 1.94 µm, is fabricated through introducing defects on the surface of bioceramic scaffolds. The B-AKT scaffolds have advantages on the degradation rate and the osteogenic capacity over the AKT (Ca₂ MgSi₂ O₇ ) scaffolds due to the surface defects which stimulate the osteogenic differentiation of rabbit bone mesenchymal stem cells via activating bone morphogenetic protein 2 （BMP2） signaling pathway and further promote bone formation in vivo. In addition, the prepared B-AKT scaffolds, the temperature of which can be over 100 °C under the near infrared （NIR） irradiation (0.66 W cm^-2 ), possess excellent performance on photothermal and antitumor effects. The work develops an introducing-defect strategy for regulating the biological performance of bioceramic scaffolds, which is expected to be applied in the next generation of bioceramic scaffolds for regenerative medicine.

Progress of Phototherapy Applications in the Treatment of Bone Cancer

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

3D Printed Multifunctional Ti6Al4V-Based Hybrid Scaffold for the Management of Osteosarcoma

Osteosarcoma is a challenging bone disease which is commonly associated with critically sized bone defects and cancer recurrence. Here, we designed and developed a multifunctional, hierarchical structured bone scaffold which can meet the demanding requirements for osteosarcoma management. The 3D printed Ti6Al4V scaffold with hydrothermally induced TiO2/TiP coating can offer a unique photothermal conversion property for in vitro bone cancer ablation. The scaffold is also infused with drug-laden gelatin/hydroxyapatite nanocomposite, which provides the ideal porous structure for cell adhesion/bone ingrowth and promotes bone regeneration. The scaffold has been thoroughly characterized by SEM/EDX, TEM, XPS, XRD, TGA, and UV-vis, and its in vitro bone cancer ablation efficiency has been validated using MG-63 cells. The hybrid scaffold showed excellent biocompatibility, and its osteointegration function has been demonstrated using an animal model.

Gold nanorods and nanohydroxyapatite hybrid hydrogel for preventing bone tumor recurrence via postoperative photothermal therapy and bone regeneration promotion

Osteosarcoma is a malignant bone tumor, which often occurs in adolescents. However, surgical resection usually fails to completely remove the tumor clinically, which has been the main cause of postoperative recurrence and metastasis, resulting in the high death rate of patients. At the same time, osteosarcoma invades a large area of the bone defect, which cannot be self-repaired and seriously affects the life quality of the patients. Herein, a bifunctional methacrylated gelatin/methacrylated chondroitin sulfate hydrogel hybrid gold nanorods (GNRs) and nanohydroxyapatite (nHA), which possessed excellent photothermal effect, was constructed to eradicate residual tumor after surgery and bone regeneration. In vitro, K7M2wt cells (a mouse bone tumor cell line) can be efficiently eradicated by photothermal therapy of the hybrid hydrogel. Meanwhile, the hydrogel mimics the extracellular matrix to promote proliferation and osteogenic differentiation of mesenchymal stem cells. The GNRs/nHA hybrid hydrogel was capable of photothermal treatment of postoperative tumors and bone defect repair in a mice model of tibia osteosarcoma. Therefore, the hybrid hydrogel possesses dual functions of tumor therapy and bone regeneration, which shows great potential in curing bone tumors and provides a new hope for tumor-related bone complex disease.

Progress of biomaterials for bone tumor therapy

Bone tumors are currently a major clinical challenge. In recent decades, strategies using well-designed versatile biomaterials for the treatment of bone tumors have emerged and attracted extensive research interest. Suitable biomaterials not only facilitate repair for bone defects aroused by surgical intervention but also help deliver antineoplastic drugs to the target site or provide photothermal/magnetothermal therapy to kill bone tumor cells. Thus, the development of biomaterials exhibits a great perspective for future bone tumor treatment.We summarize the recent progress of versatile biomaterials for bone tumor therapy, with an emphasis on photothermal/magnetothermal therapy and drug delivery.With the further understanding and development of biomaterials, multifunctional biomaterials have been proposed for bone tumor treatment. Through the interdisciplinary cooperation from the fields of biomedicine, clinical medicine and engineering, multifunctional biomaterials will perfectly match individual bone defects in the clinic with low cost in the future.

The Effect of Thermal Oxidation on the Photothermal Conversion Property of Tantalum Coatings

In this study, tantalum coatings are deposited by a plasma spraying method aiming at enhancing the biocompatibility of the titanium implant. Tantalum oxide coatings are gained through the thermal oxidation of tantalum coatings at different temperatures for photothermal therapy. The effect of thermal oxidation on the morphology, composition, and structure of tantalum coatings has been studied. The UV-VIS-NIR spectra results, cancer therapy effect in vitro, and photothermal conversion properties among the tantalum oxide coatings under varied thermal treatment conditions are compared comprehensively. It has been proven that the tantalum coating treated at 200 °C exhibits the most intense NIR adsorption, the highest photothermal conversion effect, and the most excellent photothermal ablation effect in vitro. The results reveal that incomplete oxidation at a low temperature leads to the formation of oxygen vacancies, which narrow the band gap; this promotes its photothermal conversion ability.

A Review on Hydrogels with Photothermal Effect in Wound Healing and Bone Tissue Engineering

Photothermal treatment (PTT) is a promising strategy to deal with multidrug-resistant bacteria infection and promote tissue regeneration. Previous studies demonstrated that hyperthermia can effectively inhibit the growth of bacteria, whereas mild heat can promote cell proliferation, further accelerating wound healing and bone regeneration. Especially, hydrogels with photothermal properties could achieve remotely controlled drug release. In this review, we introduce a photothermal agent hybrid in hydrogels for a photothermal effect. We also summarize the potential mechanisms of photothermal hydrogels regarding antibacterial action, angiogenesis, and osteogenesis. Furthermore, recent developments in photothermal hydrogels in wound healing and bone regeneration applications are introduced. Finally, future application of photothermal hydrogels is discussed. Hydrogels with photothermal effects provide a new direction for wound healing and bone regeneration, and this review will give a reference for the tissue engineering.

Graphene Integrated Hydrogels Based Biomaterials in Photothermal Biomedicine

Recently, photothermal therapy (PTT) has emerged as one of the most promising biomedical strategies for different areas in the biomedical field owing to its superior advantages, such as being noninvasive, target-specific and having fewer side effects. Graphene-based hydrogels (GGels), which have excellent mechanical and optical properties, high light-to-heat conversion efficiency and good biocompatibility, have been intensively exploited as potential photothermal conversion materials. This comprehensive review summarizes the current development of graphene-integrated hydrogel composites and their application in photothermal biomedicine. The latest advances in the synthesis strategies, unique properties and potential applications of photothermal-responsive GGel nanocomposites in biomedical fields are introduced in detail. This review aims to provide a better understanding of the current progress in GGel material fabrication, photothermal properties and potential PTT-based biomedical applications, thereby aiding in more research efforts to facilitate the further advancement of photothermal biomedicine.

Review of a new bone tumor therapy strategy based on bifunctional biomaterials

Bone tumors, especially those in osteosarcoma, usually occur in adolescents. The standard clinical treatment includes chemotherapy, surgical therapy, and radiation therapy. Unfortunately, surgical resection often fails to completely remove the tumor, which is the main cause of postoperative recurrence and metastasis, resulting in a high mortality rate. Moreover, bone tumors often invade large areas of bone, which cannot repair itself, and causes a serious effect on the quality of life of patients. Thus, bone tumor therapy and bone regeneration are challenging in the clinic. Herein, this review presents the recent developments in bifunctional biomaterials to achieve a new strategy for bone tumor therapy. The selected bifunctional materials include 3D-printed scaffolds, nano/microparticle-containing scaffolds, hydrogels, and bone-targeting nanomaterials. Numerous related studies on bifunctional biomaterials combining tumor photothermal therapy with enhanced bone regeneration were reviewed. Finally, a perspective on the future development of biomaterials for tumor therapy and bone tissue engineering is discussed. This review will provide a useful reference for bone tumor-related disease and the field of complex diseases to combine tumor therapy and tissue engineering.

Bifunctional scaffolds of hydroxyapatite/poly(dopamine)/carboxymethyl chitosan with osteogenesis and anti-osteosarcoma effect

Bifunctional scaffolds prepared by hydroxyapatite/poly(dopamine)/carboxymethyl chitosan with good osteogenesis and anti-osteosarcoma effect is promising for bone tumor therapy.

Osteoconductive and Osteoinductive Surface Modifications of Biomaterials for Bone Regeneration: A Concise Review

The main aim of bone tissue engineering is to fabricate highly biocompatible, osteoconductive and/or osteoinductive biomaterials for tissue regeneration. Bone implants should support bone growth at the implantation site via promotion of osteoblast adhesion, proliferation, and formation of bone extracellular matrix. Moreover, a very desired feature of biomaterials for clinical applications is their osteoinductivity, which means the ability of the material to induce osteogenic differentiation of mesenchymal stem cells toward bone-building cells (osteoblasts). Nevertheless, the development of completely biocompatible biomaterials with appropriate physicochemical and mechanical properties poses a great challenge for the researchers. Thus, the current trend in the engineering of biomaterials focuses on the surface modifications to improve biological properties of bone implants. This review presents the most recent findings concerning surface modifications of biomaterials to improve their osteoconductivity and osteoinductivity. The article describes two types of surface modifications: (1) Additive and (2) subtractive, indicating biological effects of the resultant surfaces in vitro and/or in vivo. The review article summarizes known additive modifications, such as plasma treatment, magnetron sputtering, and preparation of inorganic, organic, and composite coatings on the implants. It also presents some common subtractive processes applied for surface modifications of the biomaterials (i.e., acid etching, sand blasting, grit blasting, sand-blasted large-grit acid etched (SLA), anodizing, and laser methods). In summary, the article is an excellent compendium on the surface modifications and development of advanced osteoconductive and/or osteoinductive coatings on biomaterials for bone regeneration.

NIR light-assisted phototherapies for bone-related diseases and bone tissue regeneration: A systematic review

Recently, the rapid development of biomaterials has induced great interest in the precisely targeted treatment of bone-related diseases, including bone cancers, infections, and inflammation. Realizing noninvasive therapeutic effects, as well as improving bone tissue regeneration, is essential for the success of bone‑related disease therapies. In recent years, researchers have focused on the development of stimuli-responsive strategies to treat bone-related diseases and to realize bone regeneration. Among the various external stimuli for targeted therapy, near infrared (NIR) light has attracted considerable interests due to its high tissue penetration capacity, minimal damage toward normal tissues, and easy remote control properties. The main objective of this systematic review was to reveal the current applications of NIR light-assisted phototherapy for bone-related disease treatment and bone tissue regeneration. Database collection was completed by June 1, 2020, and a total of 81 relevant studies were finally included. We outlined the various therapeutic applications of photothermal, photodynamic and photobiomodulation effects under NIR light irradiation for bone‑related disease treatment and bone regeneration, based on the retrieved literatures. In addition, the advantages and promising applications of NIR light-responsive drug delivery systems for spatiotemporal-controlled therapy were summarized. These findings have revealed that NIR light-assisted phototherapy plays an important role in bone-related disease treatment and bone tissue regeneration, with significant promise for further biomedical and clinical applications.

Volatile-Organic-Compound-Intercepting Solar Distillation Enabled by a Photothermal/Photocatalytic Nanofibrous Membrane with Dual-Scale Pores

Solar distillation is emerging as a robust and energy-effective tool for water purification and freshwater production. However, many water sources contain harmful volatile organic compounds (VOCs), which can evaporate through the photothermal evaporators and be collected together with distilled water, or even be enriched in the distilled water. In view of the penetration of volatile organic compounds, herein, we rationally demonstrate a dual-scale porous, photothermal/photocatalytic, flexible membrane for intercepting volatile organic compounds during solar distillation, which is based on a mesoporous oxygen-vacancy-rich TiO_2-x nanofibrous membrane (m-TiO_2-x NFM). The dual-scale porous structure was constructed by micrometer-sized interconnected tortuous pores formed by the accumulation of m-TiO_2-x nanofibers and nanometer-sized pores in the m-TiO_2-x individual nanofibers. Consequently, the membrane can sustainably in situ intercept VOCs by providing more photocatalytic reactive sites for collision (mainly by mesopores) and longer tortuous channels for prolonging VOC retention (mainly by micrometer-sized pores); thus, it results in less than 5% of phenol residual in distilled water. As a proof of concept, when the m-TiO_2-x NFM is employed to purify practical river water in an evaporation prototype under real solar irradiation, complex volatile natural organic contaminants can be effectively intercepted and the produced distilled water meets the drinking water standards of China. This development will promote the application prospects of solar distillation.

Ce6/Mn2+-chelated polydopamine@black-TiO2 nanoprobes for enhanced synergistic phototherapy and magnetic resonance imaging in 4T1 breast cancer

Black titanium dioxide (TiO2) nanoparticles have attracted great attention due to their application in photothermal therapy (PTT). However, single-mode phototherapy has the risk of recurrence, and the high-dose laser usually imposed to improve the PTT performance can bring a potential threat to security. Here, polydopamine (PDA)-coated black TiO2 (b-P25@PDA) nanoparticles with a core-shell structure were synthesized for enhanced PTT; then, synergistic phototherapy nanoprobes (b-P25@PDA-Ce6 (Mn)) were constructed by coupling chlorin e6 (Ce6) and chelating Mn2+ for simultaneous photodynamic therapy (PDT)/PTT and magnetic resonance (MR) imaging, in which a low-dose laser was used and imaging-guided phototherapy with high efficiency and high safety was achieved. The prepared nanoprobes showed high photothermal conversion efficiency (32.12%), high reactive oxygen generation and excellent MR imaging. In the 4T1 tumor-bearing nude mouse model, the tumors completely disappeared under the combination of PDT/PTT with a low-dose laser but were only partially inhibited by single PDT and single PTT. The current work developed a multifunctional black TiO2-based nanoprobe for enhanced synergistic PDT/PTT and MR imaging, which will be important for the safe and efficient visualized theranostics of cancers.