A bifunctional scaffold with CuFeSe2 nanocrystals for tumor therapy and bone reconstruction

Multifunctional scaffolds for bone repair following age-related biological decline: Promising prospects for smart biomaterial-driven technologies

The repair of large bone defects due to trauma, disease, and infection can be exceptionally challenging in the elderly. Despite best clinical practice, bone regeneration within contemporary, surgically implanted synthetic scaffolds is often problematic, inconsistent, and insufficient where additional osteobiological support is required to restore bone. Emergent smart multifunctional biomaterials may drive important and dynamic cellular crosstalk that directly targets, signals, stimulates, and promotes an innate bone repair response following age-related biological decline and when in the presence of disease or infection. However, their role remains largely undetermined. By highlighting their mechanism/s and mode/s of action, this review spotlights smart technologies that favorably align in their conceivable ability to directly target and enhance bone repair and thus are highly promising for future discovery for use in the elderly. The four degrees of interactive scaffold smartness are presented, with a focus on bioactive, bioresponsive, and the yet-to-be-developed autonomous scaffold activity. Further, cell- and biomolecular-assisted approaches were excluded, allowing for contemporary examination of the capabilities, demands, vision, and future requisites of next-generation biomaterial-induced technologies only. Data strongly supports that smart scaffolds hold significant promise in the promotion of bone repair in patients with a reduced osteobiological response. Importantly, many techniques have yet to be tested in preclinical models of aging. Thus, greater clarity on their proficiency to counteract the many unresolved challenges within the scope of aging bone is highly warranted and is arguably the next frontier in the field. This review demonstrates that the use of multifunctional smart synthetic scaffolds with an engineered strategy to circumvent the biological insufficiencies associated with aging bone is a viable route for achieving next-generation therapeutic success in the elderly population.

Nanotechnology and bioengineering approaches to improve the potency of mesenchymal stem cell as an off-the-shelf versatile tumor delivery vehicle

Targeting actionable mutations in oncogene-driven cancers and the evolution of immuno-oncology are the two prominent revolutions that have influenced cancer treatment paradigms and caused the emergence of precision oncology. However, intertumoral and intratumoral heterogeneity are the main challenges in both fields of precision cancer treatment. In other words, finding a universal marker or pathway in patients suffering from a particular type of cancer is challenging. Therefore, targeting a single hallmark or pathway with a single targeted therapeutic will not be efficient for fighting against tumor heterogeneity. Mesenchymal stem cells (MSCs) possess favorable characteristics for cellular therapy, including their hypoimmune nature, inherent tumor-tropism property, straightforward isolation, and multilineage differentiation potential. MSCs can be loaded with various chemotherapeutics and oncolytic viruses. The combination of these intrinsic features with the possibility of genetic manipulation makes them a versatile tumor delivery vehicle that can be used for in vivo selective tumor delivery of various chemotherapeutic and biological therapeutics. MSCs can be used as biofactory for the local production of chemical or biological anticancer agents at the tumor site. MSC-mediated immunotherapy could facilitate the sustained release of immunotherapeutic agents specifically at the tumor site, and allow for the achievement of therapeutic concentrations without the need for repetitive systemic administration of high therapeutic doses. Despite the enthusiasm evoked by preclinical studies that used MSC in various cancer therapy approaches, the translation of MSCs into clinical applications has faced serious challenges. This manuscript, with a critical viewpoint, reviewed the preclinical and clinical studies that have evaluated MSCs as a selective tumor delivery tool in various cancer therapy approaches, including gene therapy, immunotherapy, and chemotherapy. Then, the novel nanotechnology and bioengineering approaches that can improve the potency of MSC for tumor targeting and overcoming challenges related to their low localization at the tumor sites are discussed.

Recent Advances in 3D Printing of Smart Scaffolds for Bone Tissue Engineering and Regeneration

The repair and functional reconstruction of bone defects resulting from severe trauma, surgical resection, degenerative disease, and congenital malformation pose significant clinical challenges. Bone tissue engineering (BTE) holds immense potential in treating these severe bone defects, without incurring prevalent complications associated with conventional autologous or allogeneic bone grafts. 3D printing technology enables control over architectural structures at multiple length scales and has been extensively employed to process biomimetic scaffolds for BTE. In contrast to inert and functional bone grafts, next-generation smart scaffolds possess a remarkable ability to mimic the dynamic nature of native extracellular matrix (ECM), thereby facilitating bone repair and regeneration. Additionally, they can generate tailored and controllable therapeutic effects, such as antibacterial or antitumor properties, in response to exogenous and/or endogenous stimuli. This review provides a comprehensive assessment of the progress of 3D-printed smart scaffolds for BTE applications. It begins with an introduction to bone physiology, followed by an overview of 3D printing technologies utilized for smart scaffolds. Notable advances in various stimuli-responsive strategies, therapeutic efficacy, and applications of 3D-printed smart scaffolds are discussed. Finally, the review highlights the existing challenges in the development and clinical implementation of smart scaffolds, as well as emerging technologies in this field.

Mg alloys with antitumor and anticorrosion properties for orthopedic oncology: A review from mechanisms to application strategies

As a primary malignant bone cancer, osteosarcoma (OS) poses a great threat to human health and is still a huge challenge for clinicians. At present, surgical resection is the main treatment strategy for OS. However, surgical intervention will result in a large bone defect, and some tumor cells remaining around the excised bone tissue often lead to the recurrence and metastasis of OS. Biomedical Mg-based materials have been widely employed as orthopedic implants in bone defect reconstruction, and, especially, they can eradicate the residual OS cells due to the antitumor activities of their degradation products. Nevertheless, the fast corrosion rate of Mg alloys has greatly limited their application scope in the biomedical field, and the improvement of the corrosion resistance will impair the antitumor effects, which mainly arise from their rapid corrosion. Hence, it is vital to balance the corrosion resistance and the antitumor activities of Mg alloys. The presented review systematically discussed the potential antitumor mechanisms of three corrosion products of Mg alloys. Moreover, several strategies to simultaneously enhance the anticorrosion properties and antitumor effects of Mg alloys were also proposed.

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.

Advances and Trends of Photoresponsive Hydrogels for Bone Tissue Engineering

The development of static hydrogels as an optimal choice for bone tissue engineering (BTE) remains a difficult challenge primarily due to the intricate nature of bone healing processes, continuous physiological functions, and pathological changes. Hence, there is an urgent need to exploit smart hydrogels with programmable properties that can effectively enhance bone regeneration. Increasing evidence suggests that photoresponsive hydrogels are promising bioscaffolds for BTE due to their advantages such as controlled drug release, cell fate modulation, and the photothermal effect. Here, we review the current advances in photoresponsive hydrogels. The mechanism of photoresponsiveness and its advanced applications in bone repair are also elucidated. Future research would focus on the development of more efficient, safer, and smarter photoresponsive hydrogels for BTE. This review is aimed at offering comprehensive guidance on the trends of photoresponsive hydrogels and shedding light on their potential clinical application in BTE.

Near-infrared light-activatable, analgesic nanocomposite delivery system for comprehensive therapy of diabetic wounds in rats

Impaired angiogenesis, bacterial infection, persistent severe pain, exacerbated inflammation, and oxidative stress injury are intractable problems in the treatment of chronic diabetic ulcer wounds. A strategy that effectively targets all these issues has proven challenging. Herein, an in-situ sprayable nanoparticle-gel composite comprising platinum clusters (Pt) loaded-mesoporous polydopamine (MPDA) nanoparticle and QX-314-loaded fibrin gel (Pt@MPDA/QX314@Fibrin) was developed for diabetic wound analgesia and therapy. The composite shows good local analgesic effect of QX-314 mediated by near-infrared light (NIR) activation of transient receptor potential vanilloid 1 (TRPV1) channel, as well as multifunctional therapeutic effects of rapid hemostasis, anti-inflammation, antioxidation, and antibacterial properties that benefit the fast-healing of diabetic wounds. Furthermore, it demonstrates that the composite, with good biodegradability and biosafety, significantly relieved wound pain by inhibiting the expression of c-Fos in the dorsal root ganglion and the activation of glial cells in the spinal cord dorsal horn. Consequently, our designed sprayable Pt@MPDA/QX314@Fibrin composite with good biocompatibility, NIR activation of TRPV1 channel-mediated QX-314 local wound analgesia and comprehensive treatments, is promising for chronic diabetic wound therapy.

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

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

3D Printing Drug-Free Scaffold with Triple-Effect Combination Induced by Copper-Doped Layered Double Hydroxides for the Treatment of Bone Defects

Tissue-engineered poly(l-lactide) (PLLA) scaffolds have been widely used to treat bone defects; however, poor biological activities have always been key challenges for its further application. To address this issue, introducing bioactive drugs or factors is the most commonly used method, but there are often many problems such as high cost, uncontrollable and monotonous drug activity, and poor bioavailability. Here, a drug-free 3D printing PLLA scaffold with a triple-effect combination induced by surface-modified copper-doped layered double hydroxides (Cu-LDHs) is proposed. In the early stage of scaffold implantation, Cu-LDHs exert a photothermal therapy (PTT) effect to generate high temperature to effectively prevent bacterial infection. In the later stage, Cu-LDHs can further have a mild hyperthermia (MHT) effect to stimulate angiogenesis and osteogenic differentiation, demonstrating excellent vascularization and osteogenic activity. More importantly, with the degradation of Cu-LDHs, the released Cu2+ and Mg2+ provide an ion microenvironment effect and further synergize with the MHT effect to stimulate angiogenesis and osteogenic differentiation, thus more effectively promoting the healing of bone tissue. This triple-effect combined scaffold exhibits outstanding antibacterial, osteogenic, and angiogenic activities, as well as the advantages of low cost, convenient procedure, and long-term efficacy, and is expected to provide a promising strategy for clinical repair of bone defects.

Advances in the Application of Photothermal Composite Scaffolds for Osteosarcoma Ablation and Bone Regeneration

Photothermal therapy is a promising approach to cancer treatment. The energy generated by the photothermal effect can effectively inhibit the growth of cancer cells without harming normal tissues, while the right amount of heat can also promote cell proliferation and accelerate tissue regeneration. Various nanomaterials have recently been used as photothermal agents (PTAs). The photothermal composite scaffolds can be obtained by introducing PTAs into bone tissue engineering (BTE) scaffolds, which produces a photothermal effect that can be used to ablate bone cancer with subsequent further use of the scaffold as a support to repair the bone defects created by ablation of osteosarcoma. Osteosarcoma is the most common among primary bone malignancies. However, a review of the efficacy of different types of photothermal composite scaffolds in osteosarcoma is lacking. This article first introduces the common PTAs, BTE materials, and preparation methods and then systematically summarizes the development of photothermal composite scaffolds. It would provide a useful reference for the combination of tumor therapy and tissue engineering in bone tumor-related diseases and complex diseases. It will also be valuable for advancing the clinical applications of photothermal composite scaffolds.

Mild photothermal therapy assist in promoting bone repair: Related mechanism and materials

Achieving precision treatment in bone tissue engineering (BTE) remains a challenge. Photothermal therapy (PTT), as a form of precision therapy, has been extensively investigated for its safety and efficacy. It has demonstrated significant potential in the treatment of orthopedic diseases such as bone tumors, postoperative infections and osteoarthritis. However, the high temperatures associated with PTT can lead to certain limitations and drawbacks. In recent years, researchers have explored the use of biomaterials for mild photothermal therapy (MPT), which offers a promising approach for addressing these limitations. This review provides a comprehensive overview of the mechanisms underlying MPT and presents a compilation of photothermal agents and their utilization strategies for bone tissue repair. Additionally, the paper discusses the future prospects of MPT-assisted bone tissue regeneration, aiming to provide insights and recommendations for optimizing material design in this field.

Bifunctional bone substitute materials for bone defect treatment after bone tumor resection

Aggressive benign, malignant and metastatic bone tumors can greatly decrease the quality of patients' lives and even lead to substantial mortality. Several clinical therapeutic strategies have been developed to treat bone tumors, including preoperative chemotherapy, surgical resection of the tumor tissue, and subsequent systemic chemo- or radiotherapy. However, those strategies are associated with inevitable drawbacks, such as severe side effects, substantial local tumor recurrence, and difficult-to-treat bone defects after tumor resection. To overcome these shortcomings and achieve satisfactory clinical outcomes, advanced bifunctional biomaterials which simultaneously promote bone regeneration and combat bone tumor growth are increasingly advocated. These bifunctional bone substitute materials fill bone defects following bone tumor resection and subsequently exert local anticancer effects. Here we describe various types of the most prevalent bone tumors and provide an overview of common treatment options. Subsequently, we review current progress regarding the development of bifunctional bone substitute materials combining osteogenic and anticancer efficacy. To this end, we categorize these biomaterials based on their anticancer mechanism deriving from i) intrinsic biomaterial properties, ii) local drug release of anticancer agents, and iii) oxidative stress-inducing and iv) hyperthermia-inducing biomaterials. Consequently, this review offers researchers, surgeons and oncologists an up-to-date overview of our current knowledge on bone tumors, their treatment options, and design of advanced bifunctional biomaterials with strong potential for clinical application in oncological orthopedics.

Photothermal therapy of copper incorporated nanomaterials for biomedicine

Studies have reported on the significance of copper incorporated nanomaterials (CINMs) in cancer theranostics and tissue regeneration. Given their unique physicochemical properties and tunable nanostructures, CINMs are used in photothermal therapy (PTT) and photothermal-derived combination therapies. They have the potential to overcome the challenges of unsatisfactory efficacy of conventional therapies in an efficient and non-invasive manner. This review summarizes the recent advances in CINMs-based PTT in biomedicine. First, the classification and structure of CINMs are introduced. CINMs-based PTT combination therapy in tumors and PTT guided by multiple imaging modalities are then reviewed. Various representative designs of CINMs-based PTT in bone, skin and other organs are presented. Furthermore, the biosafety of CINMs is discussed. Finally, this analysis delves into the current challenges that researchers face and offers an optimistic outlook on the prospects of clinical translational research in this field. This review aims at elucidating on the applications of CINMs-based PTT and derived combination therapies in biomedicine to encourage future design and clinical translation.

Multifunctional bioactive glasses with spontaneous degradation for simultaneous osteosarcoma therapy and bone regeneration

For the treatment of tumor-related bone defects resulting from surgical resection, simultaneous eradication of residual tumor cells and repair of bone defects represent a challenge. To date, photothermal therapy based on photothermal materials is used to remove residual tumor cells under near infrared light. However, most of photothermal materials have no function for bone repair, and even if combined with bioactive materials to enhance osteogenesis, they still cause potential harm to the body due to inability to degrade or poor degradability. Herein, multifunctional bioactive glasses (PGFe5-1100, PGCu5-1100) based on phosphate glass doped with transition metal elements were prepared for photothermal ablation, bone regeneration, and controllable degradation. The glasses exhibited excellent photothermal effect, which was derived from the electron in-band transition after light absorption due to energy level splitting of doped transition metal element and the subsequent electron nonradiative relaxation. The photothermal performance can be controlled by laser power density, element doping content and glass melting temperature. Moreover, the hyperthermia induced by the glasses can effectively kill tumor cells in vitro. In addition, the glasses degraded over time, and the released P, Ca, Na, Fe could promote bone cell proliferation and osteogenic differentiation. Therefore, these results successfully demonstrated that transition metal element-doped phosphate glasses have multifunctional abilities of tumor elimination, bone regeneration, and spontaneous degradation simultaneously with better biosecurity and bioactivity, which is believed to pave the way for the design of novel biomaterials for osteosarcoma treatment.

Functional anti-bone tumor biomaterial scaffold: construction and application

Bone tumors, including primary bone tumors and bone metastases, have been plagued by poor prognosis for decades. Although most tumor tissue is removed, clinicians are still confronted with the dilemma of eliminating residual cancer cells and regenerating defective bone tissue after surgery. Therefore, functional biomaterial scaffolds are considered to be the ideal candidates to bridge defective tissues and restrain cancer recurrence. Through functionalized structural modifications or coupled therapeutic agents, they provide sufficient mechanical strength and osteoinductive effects while eliminating cancer cells. Numerous novel approaches such as photodynamic, photothermal, drug-conjugated, and immune adjuvant-assisted therapies have exhibited remarkable efficacy against tumors while exhibiting low immunogenicity. This review summarizes the progress of research on biomaterial scaffolds based on different functionalization strategies in bone tumors. We also discuss the feasibility and advantages of the combined application of multiple functionalization strategies. Finally, potential obstacles to the clinical translation of anti-tumor bone bioscaffolds are highlighted. This review will provide valuable references for future advanced biomaterial scaffold design and clinical bone tumor therapy.

Performance optimization of biomimetic ant-nest silver nanoparticle coatings for antibacterial and osseointegration of implant surfaces

Infection prevention and bone-implant integration remain major clinical challenges. Silver nanoparticle (AgNPs) bone-implant coatings have received extensive attention. Balancing the toxicity and antibacterial properties of AgNP coatings has become a significant problem. In this study, inspired by the structure of the ant-nest, a polyetherimide (PEI) coating with ant-nest structure was prepared, aiming to realize the structural modification of the AgNPs coating. AgNPs were loaded in the inner porous area of the PEI ant-nest coating, avoiding direct contact between AgNPs and cells. The nanopores on the surface of the coating ensured the orderly release of silver ions. SEM, FTIR, XPS, and XRD experiments confirmed that the PEI ant-nest coating was successfully prepared. Interestingly, in the PEI ant-nest coating, Ag⁺ showed a steady increase in the release trend within 28 days, and there was no early burst release phenomenon. In -vivo experiments showed a good control effect for local infection. In order to improve the osteogenic properties of the materials, 45S5 bioactive glasses (BG) were loaded to achieve further osseointegration. In general, this natural ant-nest-inspired surface modification coating for orthopedic prostheses provides a new strategy for balancing the antibacterial and toxic effects of AgNP coatings.

Organic Photothermal Cocrystals: Rational Design, Controlled Synthesis, and Advanced Application

Organic photothermal cocrystals, integrating the advantages of intrinsic organic cocrystals and the fascinating photothermal conversion ability, hold attracted considerable interest in both basic science and practical applications, involving photoacoustic imaging, seawater desalination, and photothermal therapy, and so on. However, these organic photothermal cocrystals currently suffer individual cases discovered step by step, as well as the deep and systemic investigation in the corresponding photothermal conversion mechanisms is rarely carried out, suggesting a huge challenge for their further developments. Therefore, it is urgently necessary to investigate and explore the rational design and synthesis of high-performance organic photothermal cocrystals for future applications. This review first and systematically summarizes the organic photothermal cocrystal in terms of molecular classification, the photothermal conversion mechanism, and their corresponding applications. The timely interpretation of the cocrystal photothermal effect will provide broad prospects for the purposeful fabrication of excellent organic photothermal cocrystals toward great efficiency, low cost, and multifunctionality.

Novel coatings for the continuous repair of human bone defects

Bone defects are the second most common tissue grafts after blood. However, bone grafts face several problems, such as bone scaffolds, which have low bioactivity and are prone to corrosion. Much of the current research on bone scaffolds is focused on the mechanical aspects such as structure and strength. Surface modification of the bone scaffold is carried out in terms of the mechanical structure or structural design of the bone scaffold with reference to a bionic structure. However, with the development of mechanical designs, materials science, and medicine, many studies have reported that promoting bone growth by modifying the structure of the scaffold or coating is not possible. Therefore, the application of a bioactive coating to the surface of the bone scaffold is particularly important to generate a synergistic effect between the structure and active coating. In this article, we present several perspectives to improve the bioactivity of bone scaffolds, including corrosion resistance, loading of bioactive coatings or drugs on bone scaffolds, improved adhesion to the surface of the bone scaffolds, immune response modulation, and drawing on bionic structures during manufacturing.

Two Hawks with One Arrow: A Review on Bifunctional Scaffolds for Photothermal Therapy and Bone Regeneration

Despite the significant improvement in the survival rate of cancer patients, the total cure of bone cancer is still a knotty clinical challenge. Traditional surgical resectionof bone tumors is less than satisfactory, which inevitably results in bone defects and the inevitable residual tumor cells. For the purpose of realizing minimal invasiveness and local curative effects, photothermal therapy (PTT) under the irradiation of near-infrared light has made extensive progress in ablating tumors, and various photothermal therapeutic agents (PTAs) for the treatment of bone tumors have thus been reported in the past few years, has and have tended to focus on osteogenic bio-scaffolds modified with PTAs in order to break through the limitation that PTT lacks, osteogenic capacity. These so-called bifunctional scaffolds simultaneously ablate bone tumors and generate new tissues at the bone defects. This review summarizes the recent application progress of various bifunctional scaffolds and puts forward some practical constraints and future perspectives on bifunctional scaffolds for tumor therapy and bone regeneration: two hawks with one arrow.

Additively manufactured Bi-functionalized bioceramics for reconstruction of bone tumor defects

Bone tissue exhibits critical factors for metastatic cancer cells and represents an extremely pleasant spot for further growth of tumors. The number of metastatic bone lesions and primary tumors that arise directly from cells comprised in the bone milieu is constantly increasing. Bioceramics have recently received significant attention in bone tissue engineering and local drug delivery applications. Additionally, additive manufacturing of bioceramics offers unprecedented advantages including the possibilities to fill irregular voids after the resection and fabricate patient-specific implants. Herein, we investigated the recent advances in additively manufactured bioceramics and ceramic-based composites that were used in the local bone tumor treatment and reconstruction of bone tumor defects. Furthermore, it has been extensively explained how to bi-functionalize ceramics-based biomaterials and what current limitations impede their clinical application. We have also discussed the importance of further development into ceramic-based biomaterials and molecular biology of bone tumors to: (1) discover new potential therapeutic targets to enhance conventional therapies, (2) local delivering of bio-molecular agents in a customized and "smart" way, and (3) accomplish a complete elimination of tumor cells in order to prevent tumor recurrence formation. We emphasized that by developing the research focus on the introduction of novel 3D-printed bioceramics with unique properties such as stimuli responsiveness, it will be possible to fabricate smart bioceramics that promote bone regeneration while minimizing the side-effects and effectively eradicate bone tumors while promoting bone regeneration. In fact, by combining all these therapeutic strategies and additive manufacturing, it is likely to provide personalized tumor-targeting therapies for cancer patients in the foreseeable future. STATEMENT OF SIGNIFICANCE: To increase the survival rates of cancer patients, different strategies such as surgery, reconstruction, chemotherapy, radiotherapy, etc have proven to be essential. Nonetheless, these therapeutic protocols have reached a plateau in their effectiveness due to limitations including drug resistance, tumor recurrence after surgery, toxic side-effects, and impaired bone regeneration following tumor resection. Hence, novel approaches to specifically and locally attack cancer cells, while also regenerating the damaged bony tissue, have being developed in the past years. This review sheds light to the novel approaches that enhance local bone tumor therapy and reconstruction procedures by combining additive manufacturing of ceramic biomaterials and other polymers, bioactive molecules, nanoparticles to affect bone tumor functions, metabolism, and microenvironment.

Multifunctional 3D-printed bioceramic scaffolds: Recent strategies for osteosarcoma treatment

Osteosarcoma is the most prevalent bone malignant tumor in children and teenagers. The bone defect, recurrence, and metastasis after surgery severely affect the life quality of patients. Clinically, bone grafts are implanted. Primary bioceramic scaffolds show a monomodal osteogenesis function. With the advances in three-dimensional printing technology and materials science, while maintaining the osteogenesis ability, scaffolds become more patient-specific and obtain additional anti-tumor ability with functional agents being loaded. Anti-tumor therapies include photothermal, magnetothermal, old and novel chemo-, gas, and photodynamic therapy. These strategies kill tumors through novel mechanisms to treat refractory osteosarcoma due to drug resistance, and some have shown the potential to reverse drug resistance and inhibit metastasis. Therefore, multifunctional three-dimensional printed bioceramic scaffolds hold excellent promise for osteosarcoma treatments. To better understand, we review the background of osteosarcoma, primary 3D-printed bioceramic scaffolds, and different therapies and have a prospect for the future.

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.

Biomaterial-assisted tumor therapy: A brief review of hydroxyapatite nanoparticles and its composites used in bone tumors therapy

Malignant bone tumors can inflict significant damage to affected bones, leaving patients to contend with issues like residual tumor cells, bone defects, and bacterial infections post-surgery. However, hydroxyapatite nanoparticles (nHAp), the principal inorganic constituent of natural bone, possess numerous advantages such as high biocompatibility, bone conduction ability, and a large surface area. Moreover, nHAp's nanoscale particle size enables it to impede the growth of various tumor cells via diverse pathways. This article presents a comprehensive review of relevant literature spanning the past 2 decades concerning nHAp and bone tumors. The primary goal is to explore the mechanisms responsible for nHAp's ability to hinder tumor initiation and progression, as well as to investigate the potential of integrating other drugs and components for bone tumor diagnosis and treatment. Lastly, the article discusses future prospects for the development of hydroxyapatite materials as a promising modality for tumor therapy.

Nanomaterial-assisted theranosis of bone diseases

Bone-related diseases refer to a group of skeletal disorders that are characterized by bone and cartilage destruction. Conventional approaches can regulate bone homeostasis to a certain extent. However, these therapies are still associated with some undesirable problems. Fortunately, recent advances in nanomaterials have provided unprecedented opportunities for diagnosis and therapy of bone-related diseases. This review provides a comprehensive and up-to-date overview of current advanced theranostic nanomaterials in bone-related diseases. First, the potential utility of nanomaterials for biological imaging and biomarker detection is illustrated. Second, nanomaterials serve as therapeutic delivery platforms with special functions for bone homeostasis regulation and cellular modulation are highlighted. Finally, perspectives in this field are offered, including current key bottlenecks and future directions, which may be helpful for exploiting nanomaterials with novel properties and unique functions. This review will provide scientific guidance to enhance the development of advanced nanomaterials for the diagnosis and therapy of bone-related diseases.

Synergistic Effect of Static Magnetic Fields and 3D-Printed Iron-Oxide-Nanoparticle-Containing Calcium Silicate/Poly-ε-Caprolactone Scaffolds for Bone Tissue Engineering

In scaffold-regulated bone regeneration, most three-dimensional (3D)-printed scaffolds do not provide physical stimulation to stem cells. In this study, a magnetic scaffold was fabricated using fused deposition modeling with calcium silicate (CS), iron oxide nanoparticles (Fe₃O₄), and poly-ε-caprolactone (PCL) as the matrix for internal magnetic sources. A static magnetic field was used as an external magnetic source. It was observed that 5% Fe₃O₄ provided a favorable combination of compressive strength (9.6 ± 0.9 MPa) and degradation rate (21.6 ± 1.9% for four weeks). Furthermore, the Fe₃O₄-containing scaffold increased in vitro bioactivity and Wharton's jelly mesenchymal stem cells' (WJMSCs) adhesion. Moreover, it was shown that the Fe₃O₄-containing scaffold enhanced WJMSCs' proliferation, alkaline phosphatase activity, and the osteogenic-related proteins of the scaffold. Under the synergistic effect of the static magnetic field, the CS scaffold containing Fe₃O₄ can not only enhance cell activity but also stimulate the simultaneous secretion of collagen I and osteocalcin. Overall, our results demonstrated that Fe₃O₄-containing CS/PCL scaffolds could be fabricated three dimensionally and combined with a static magnetic field to affect cell behaviors, potentially increasing the likelihood of clinical applications for bone tissue engineering.

Functional engineering strategies of 3D printed implants for hard tissue replacement

Three-dimensional printing technology with the rapid development of printing materials are widely recognized as a promising way to fabricate bioartificial bone tissues. In consideration of the disadvantages of bone substitutes, including poor mechanical properties, lack of vascularization and insufficient osteointegration, functional modification strategies can provide multiple functions and desired characteristics of printing materials, enhance their physicochemical and biological properties in bone tissue engineering. Thus, this review focuses on the advances of functional engineering strategies for 3D printed biomaterials in hard tissue replacement. It is structured as introducing 3D printing technologies, properties of printing materials (metals, ceramics and polymers) and typical functional engineering strategies utilized in the application of bone, cartilage and joint regeneration.

A Codispersed Nanosystem of Silver-anchored MoS2 Enhances Antibacterial and Antitumor Properties of Selective Laser Sintered Scaffolds

Tumor recurrence and bacterial infection are common problems during bone repair and reconstruction after bone tumor surgery. In this study, silver-anchored MoS₂ nanosheets (Ag@PMoS₂) were synthesized by in situ reduction, then a composite polymer scaffold (Ag@PMoS₂/PGA) with sustained antitumor and antibacterial activity was successfully constructed by selective laser sintering technique. In the Ag@PMoS₂ nanostructures, silver nanoparticles (Ag NPs) were sandwiched between adjacent MoS₂ nanosheets (MoS₂ NSs), which restrained the restacking of the MoS₂ NSs. In addition, the MoS₂ NSs acted as steric hindrance layers, which prevented the aggregation of Ag NPs. More importantly, MoS₂ NSs can provide a barrier layer for Ag NPs, hindering Ag NPs from reacting with the external solution to prevent its quick release. The results showed that Ag@PMoS₂/PGA scaffolds have stronger photothermal effect and antitumor function. Meanwhile, the Ag@PMoS₂/PGA scaffolds also demonstrated slow control of silver ion (Ag⁺) release and more efficient long-term antibacterial ability. Besides, composite scaffolds have been proved to kill the MG-63 cells by inducing apoptosis and inhibit bacterial proliferation by upregulating the level of bacterial reactive oxygen species. This kind of novel bifunctional implants with antitumor and antibacterial properties provides better choice for the artificial bone transplantation after primary bone tumor resection.

Nanomaterial integrated 3D printing for biomedical applications

3D printing technology, otherwise known as additive manufacturing, has provided a promising tool for manufacturing customized biomaterials for tissue engineering and regenerative medicine applications. A vast variety of biomaterials including metals, ceramics, polymers, and composites are currently being used as base materials in 3D printing. In recent years, nanomaterials have been incorporated into 3D printing polymers to fabricate innovative, versatile, multifunctional hybrid materials that can be used in many different applications within the biomedical field. This review focuses on recent advances in novel hybrid biomaterials composed of nanomaterials and 3D printing technologies for biomedical applications. Various nanomaterials including metal-based nanomaterials, metal-organic frameworks, upconversion nanoparticles, and lipid-based nanoparticles used for 3D printing are presented, with a summary of the mechanisms, functional properties, advantages, disadvantages, and applications in biomedical 3D printing. To finish, this review offers a perspective and discusses the challenges facing the further development of nanomaterials in biomedical 3D printing.

Preparation of composite scaffolds composed of gelatin and Au nanostar-deposited black phosphorus nanosheets for the photothermal ablation of cancer cells and adipogenic differentiation of stem cells

Photothermal nanoparticles are important in photothermal therapy. Combining different nanoparticles can achieve a high photothermal capacity. In this study, composite nanoparticles composed of black phosphorus nanosheets (BPNSs) and gold nanostars (BP-AuNSs) were synthesized by using BPNSs as the reductant. AuNSs were deposited on the BPNSs. The BP-AuNSs were further hybridized with porous gelatin scaffolds to prepare gelatin-BP-AuNS composite scaffolds. The gelatin-BP-AuNS composite scaffolds promoted cell migration and distribution. The synergistic effects of the BPNSs and AuNSs endowed the gelatin-BP-AuNS composite scaffolds with excellent photothermal properties. The gelatin-BP-AuNS composite scaffolds eliminated cancer cells after near infrared laser exposure and supported the adipogenic differentiation of human mesenchymal stem cells. Thus, this gelatin-BP-AuNS composite scaffold holds promise for breast cancer therapy.

Bifunctional scaffolds for tumor therapy and bone regeneration: Synergistic effect and interplay between therapeutic agents and scaffold materials

Bone tumor patients often face the problems with cancer cell residues and bone defects after the operation. Therefore, researchers have developed many bifunctional scaffolds with both tumor treatment and bone repair functions. Therapeutic agents are usually combined with bioactive scaffolds to achieve the "bifunctional". However, the synergistic effect of bifunctional scaffolds on tumor therapy and bone repair, as well as the interplay between therapeutic agents and scaffold materials in bifunctional scaffolds, have not been emphasized and discussed. This review proposes a promising design scheme for bifunctional scaffolds: the synergistic effect and interplay between the therapeutic agents and scaffold materials. This review summarizes the latest research progress in bifunctional scaffolds for therapeutic applications and regeneration. In particular, it summarizes the role of tumor therapeutic agents in bone regeneration and the role of scaffold materials in tumor treatment. Finally, a perspective on the future development of bifunctional scaffolds for tumor therapy and bone regeneration is discussed.

Osteogenic and anti-tumor Cu and Mn-doped borosilicate nanoparticles for syncretic bone repair and chemodynamic therapy in bone tumor treatment

Critical bone defects caused by extensive excision of malignant bone tumor and the probability of tumor recurrence due to residual tumor cells make malignant bone tumor treatment a major clinical challenge. The present therapeutic strategy concentrates on implanting bone substitutes for defect filling but suffers from failures in both enhancing bone regeneration and inhibiting the growth of tumor cells. Herein, Cu and Mn-doped borosilicate nanoparticles (BSNs) were developed for syncretic bone repairing and anti-tumor treatment, which can enhance bone regeneration through the osteogenic effects of Cu²⁺ and Mn³⁺ ions and meanwhile induce tumor cells apoptosis through the hydroxyl radicals produced by the Fenton-like reactions of Cu²⁺ and Mn³⁺ ions. In vitro study showed that both osteogenic differentiation of BMSCs and angiogenesis of endothelial cells were promoted by BSNs, and consistently the critical bone defects of rats were efficiently repaired by BSNs through in vivo evaluation. Meanwhile, BSNs could generate hydroxyl radicals through Fenton-like reactions in the simulated tumor microenvironment, promote the generation of intracellular reactive oxygen species, and eventually induce tumor cell apoptosis. Besides, subcutaneous tumors of mice were effectively inhibited by BSNs without causing toxic side effects to normal tissues and organs. Altogether, Cu and Mn-doped BSNs developed in this work performed dual functions of enhancing osteogenesis and angiogenesis for bone regeneration, and inhibiting tumor growth for chemodynamic therapy, thus holding a great potential for syncretic bone repairing and anti-tumor therapy.

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Dual-functional bioactive borosilicate nanoparticles were successfully synthesized.

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Incorporation of Cu and Mn to the nanoparticles enhanced osteogenesis and angiogenesis.

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Cu and Mn doped borosilicate nanoparticles inhibited tumor by producing ·OH.

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Potential syncretic bone repair and chemodynamic therapy developed for bone tumor treatment.

Printing Technologies as an Emerging Approach in Gas Sensors: Survey of Literature

Herein, we review printing technologies which are commonly approbated at recent time in the course of fabricating gas sensors and multisensor arrays, mainly of chemiresistive type. The most important characteristics of the receptor materials, which need to be addressed in order to achieve a high efficiency of chemisensor devices, are considered. The printing technologies are comparatively analyzed with regard to, (i) the rheological properties of the employed inks representing both reagent solutions or organometallic precursors and disperse systems, (ii) the printing speed and resolution, and (iii) the thickness of the formed coatings to highlight benefits and drawbacks of the methods. Particular attention is given to protocols suitable for manufacturing single miniature devices with unique characteristics under a large-scale production of gas sensors where the receptor materials could be rather quickly tuned to modify their geometry and morphology. We address the most convenient approaches to the rapid printing single-crystal multisensor arrays at lab-on-chip paradigm with sufficiently high resolution, employing receptor layers with various chemical composition which could replace in nearest future the single-sensor units for advancing a selectivity.

Application of additively manufactured 3D scaffolds for bone cancer treatment: a review

Bone cancer is a critical health problem on a global scale, and the associated huge clinical and economic burdens are still rising. Although many clinical approaches are currently used for bone cancer treatment, these methods usually affect the normal body functions and thus present significant limitations. Meanwhile, advanced materials and additive manufacturing have opened up promising avenues for the development of new strategies targeting both bone cancer treatment and post-treatment bone regeneration. This paper presents a comprehensive review of bone cancer and its current treatment methods, particularly focusing on a number of advanced strategies such as scaffolds based on advanced functional materials, drug-loaded scaffolds, and scaffolds for photothermal/magnetothermal therapy. Finally, the main research challenges and future perspectives are elaborated.

Photothermal scaffolds/surfaces for regulation of cell behaviors

Regulation of cell behaviors and even cell fates is of great significance in diverse biomedical applications such as cancer treatment, cell-based therapy, and tissue engineering. During the past decades, diverse methods have been developed to regulate cell behaviors such as applying external stimuli, delivering exogenous molecules into cell interior and changing the physicochemical properties of the substrates where cells adhere. Photothermal scaffolds/surfaces refer to a kind of materials embedded or coated with photothermal agents that can absorb light with proper wavelength (usually in near infrared region) and convert light energy to heat; the generated heat shows great potential for regulation of cell behaviors in different ways. In the current review, we summarize the recent research progress, especially over the past decade, of using photothermal scaffolds/surfaces to regulate cell behaviors, which could be further categorized into three types: (i) killing the tumor cells via hyperthermia or thermal ablation, (ii) engineering cells by intracellular delivery of exogenous molecules via photothermal poration of cell membranes, and (iii) releasing a single cell or an intact cell sheet via modulation of surface physicochemical properties in response to heat. In the end, challenges and perspectives in these areas are commented.

Mesoporous Bioactive Glasses in Cancer Diagnosis and Therapy: Stimuli-Responsive, Toxicity, Immunogenicity, and Clinical Translation

Cancer is one of the top life-threatening dangers to the human survival, accounting for over 10 million deaths per year. Bioactive glasses have developed dramatically since their discovery 50 years ago, with applications that include therapeutics as well as diagnostics. A new system within the bioactive glass family, mesoporous bioactive glasses (MBGs), has evolved into a multifunctional platform, thanks to MBGs easy-to-functionalize nature and tailorable textural properties-surface area, pore size, and pore volume. Although MBGs have yet to meet their potential in tumor treatment and imaging in practice, recently research has shed light on the distinguished MBGs capabilities as promising theranostic systems for cancer imaging and therapy. This review presents research progress in the field of MBG applications in cancer diagnosis and therapy, including synthesis of MBGs, mechanistic overview of MBGs application in tumor diagnosis and drug monitoring, applications of MBGs in cancer therapy ( particularly, targeted delivery and stimuli-responsive nanoplatforms), and immunological profile of MBG-based nanodevices in reference to the development of novel cancer therapeutics.

The Development Tendency of 3D-Printed Bioceramic Scaffolds for Applications Ranging From Bone Tissue Regeneration to Bone Tumor Therapy

Three-dimensional (3D) printing concept has been successfully employed in regenerative medicine to achieve individualized therapy due to its benefit of a rapid, accurate, and predictable production process. Traditional biocomposites scaffolds (SCF) are primarily utilised for bone tissue engineering; nevertheless, over the last few years, there has already been a dramatic shift in the applications of bioceramic (BCR) SCF. As a direct consequence, this study focused on the structural, degeneration, permeation, and physiological activity of 3D-printed BCR (3DP-B) SCF with various conformations and work systems (macros, micros, and nanos ranges), as well as their impacts on the mechanical, degeneration, porosity, and physiological activities. In addition, 3DP-B SCF are highlighted in this study for potential uses applied from bone tissue engineering (BTE) to bone tumor treatment. The study focused on significant advances in practical 3DP-B SCF that can be utilized for tumor treatment as well as bone tissue regeneration (BTR). Given the difficulties in treating bone tumors, these operational BCR SCF offer a lot of promise in mending bone defects caused by surgery and killing any remaining tumor cells to accomplish bone tumor treatment. Furthermore, a quick assessment of future developments in this subject was presented. The study not only summarizes recent advances in BCR engineering, but it also proposes a new therapeutic strategy focused on the extension of conventional ceramics' multifunction to a particular diagnosis.

Precise Diagnosis and Therapy of Bone Cancer Using Near-Infrared Lights

Bone is a preferred site for both primary and metastasis tumors. Current diagnosis of osteopathia typically relies on noninvasive skeleton radiography technology. However, due to the limited resolution of ionizing radiation, accurate diagnosis and effective identification impairment areas are still lacking. Near-infrared (NIR) bioimaging, especially in the NIR-II (1000-1700 nm) regions, can provide high sensitivity and spatiotemporal resolution bioimaging compared to the conventional radiography. Thus, NIR bioimaging affords intraoperative visualization and imaging-guided surgery, aiming to overcome challenges associated with theranostics of osteopathia and bone tumors. The present review aimed to summarize the latest evidence on the use of NIR probes for the targeting bone imaging. We further highlight the recent advances in bone photoX (X presents thermal, dynamic, and immuno) therapy through NIR probes, in particular combination with other customized therapeutic agents could provide high-efficiency treatment for bone tumors.

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.

Converging 2D Nanomaterials and 3D Bioprinting Technology: State-of-the-Art, Challenges, and Potential Outlook in Biomedical Applications

The development of next-generation of bioinks aims to fabricate anatomical size 3D scaffold with high printability and biocompatibility. Along with the progress in 3D bioprinting, 2D nanomaterials (2D NMs) prove to be emerging frontiers in the development of advanced materials owing to their extraordinary properties. Harnessing the properties of 2D NMs in 3D bioprinting technologies can revolutionize the development of bioinks by endowing new functionalities to the current bioinks. First the main contributions of 2D NMS in 3D bioprinting technologies are categorized here into six main classes: 1) reinforcement effect, 2) delivery of bioactive molecules, 3) improved electrical conductivity, 4) enhanced tissue formation, 5) photothermal effect, 6) and stronger antibacterial properties. Next, the recent advances in the use of each certain 2D NMs (1) graphene, 2) nanosilicate, 3) black phosphorus, 4) MXene, 5) transition metal dichalcogenides, 6) hexagonal boron nitride, and 7) metal-organic frameworks) in 3D bioprinting technology are critically summarized and evaluated thoroughly. Third, the role of physicochemical properties of 2D NMSs on their cytotoxicity is uncovered, with several representative examples of each studied 2D NMs. Finally, current challenges, opportunities, and outlook for the development of nanocomposite bioinks are discussed thoroughly.

Localized delivery of immunotherapeutics: A rising trend in the field

Immunotherapy is becoming a new standard of care for multiple cancers, while several limitations are impending its further clinical success. Immunotherapeutic agents often have inappropriate pharmacokinetics on their own and/or exhibit limited specificity to tumor cells, leading to severe immuno-related adverse effects and limited efficacy. Suitable formulating strategies that confer prolonged contact with or efficient proliferation in tumors while reducing exposure to normal tissues are highly worthy to explore. With the assistance of biomaterial carriers, targeted therapy can be achieved artificially by implanting or injecting drug depots into desired sites, about which the wisdoms in literature have been rich. The relevant results have suggested a "local but systemic" effect, that is, local replenishment of immune modulators achieves a high treatment efficacy that also governs distant metastases, thereby building another rationale for localized delivery. Particularly, implantable scaffolds have been further engineered to recruit disseminated tumor cells with an efficiency high enough to reduce tumor burdens at typical metastatic organs, and simultaneously provide diagnostic signals. This review introduces recent advances in this emerging area along with a perspective on the opportunities and challenges in the way to clinical application.

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 Polyetheretherketone Bone Scaffold for Multimodal Treatment of Osteosarcoma and Osteomyelitis

In this work, we developed the first 3D-printed polyetheretherketone (PEEK)-based bone scaffold with multi-functions targeting challenging bone diseases such as osteosarcoma and osteomyelitis. A 3D-printed PEEK/graphene nanocomposite scaffold was deposited with a drug-laden (antibiotics and/or anti-cancer drugs) hydroxyapatite coating. The graphene nanosheets within the scaffold served as effective photothermal agents that endowed the scaffold with on-demand photothermal conversion function under near-infrared laser irradiation. The bioactive hydroxyapatite coating significantly boosted the stem cell proliferation in vitro and promoted new bone growth in vivo. The presence of antibiotics and anti-cancer drugs enabled eradication of drug-resistant bacteria and ablation of osteosarcoma cancer cells, the treatment efficacy of which can be further enhanced by on-demand laser-induced heating. The promising results demonstrate the strong potential of our multi-functional scaffold in applications such as bone defect repair and multimodal treatment of osteosarcoma and osteomyelitis.

3D Printed Wesselsite Nanosheets Functionalized Scaffold Facilitates NIR-II Photothermal Therapy and Vascularized Bone Regeneration

Various bifunctional scaffolds have recently been developed to address the reconstruction of tumor-initiated bone defects. Such scaffolds are usually composed of a near-infrared (NIR) photothermal conversion agent and a conventional bone scaffold for photothermal therapy (PTT) and long-term bone regeneration. However, the reported photothermal conversion agents are mainly restricted to the first biological window (NIR-I) with intrinsic poor tissue penetration depth. Also, most of these agents are non-bioactive materials, which induced potential systemic side toxicity after implantation. Herein, a NIR-II photothermal conversion agent (Wesselsite [SrCuSi4 O10 ] nanosheets, SC NSs) with tremendous osteogenic and angiogenic bioactivity, is rationally integrated with polycaprolactone (PCL) via 3D printing. The as-designed 3D composite scaffolds not only trigger osteosarcoma ablation through NIR-II light generated extensive hyperthermia, but also promote in vitro cellular proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) and human umbilical vein endothelial cells (HUVECs), respectively, and the ultimate enhancement of vascularized bone regeneration in vivo owing to the controlled and sustained release of bioactive ions (Sr, Cu, and Si). The authors' study provides a new avenue to prepare multifunctional bone scaffolds based on therapeutic bioceramics for repairing tumor-induced bone defects.

Recent Advances in the Treatment of Bone Metastases and Primary Bone Tumors: An Up-to-Date Review

In the last decades, the treatment of primary and secondary bone tumors has faced a slow-down in its development, being mainly based on chemotherapy, radiotherapy, and surgical interventions. However, these conventional therapeutic strategies present a series of disadvantages (e.g., multidrug resistance, tumor recurrence, severe side effects, formation of large bone defects), which limit their application and efficacy. In recent years, these procedures were combined with several adjuvant therapies, with different degrees of success. To overcome the drawbacks of current therapies and improve treatment outcomes, other strategies started being investigated, like carrier-mediated drug delivery, bone substitutes for repairing bone defects, and multifunctional scaffolds with bone tissue regeneration and antitumor properties. Thus, this paper aims to present the types of bone tumors and their current treatment approaches, further focusing on the recent advances in new therapeutic alternatives.

Enwrapping Polydopamine on Doxorubicin-Loaded Lamellar Hydroxyapatite/Poly(lactic-co-glycolic acid) Composite Fibers for Inhibiting Bone Tumor Recurrence and Enhancing Bone Regeneration

Simultaneous prevention of bone tumor recurrence and promotion of repairing bone defects resulting from tumorectomy remain a challenge. Herein, we report a polydopamine (PDA)-coated composite scaffold consisting of doxorubicin (DOX)-loaded lamellar hydroxyapatite (LHAp) and poly(lactic-co-glycolic acid) (PLGA) in an attempt to reach dual functions of tumor inhibition and bone repair. The DOX was intercalated into LHAp, and the DOX-loaded LHAp was incorporated into PLGA solution to prepare a DOX-intercalated LHAp/PLGA (labeled as DH/PLGA) scaffold that was coated with PDA to obtain a PDA@DH/PLGA scaffold. The morphology, structure, wettability, mechanical properties, drug release, biocompatibility, and in vitro and in vivo bioactivities of the PDA@DH/PLGA scaffold were evaluated. It is found that PDA coating not only improves hydrophilicity and mechanical properties, but also leads to more sustainable drug release. More importantly, the PDA@DH/PLGA scaffold shows significantly inhibited growth of tumor cells initially and subsequent improved adhesion and proliferation of osteoblasts. In addition, the PDA coating improves the bioactivity of the DH/PLGA scaffold as suggested by the in vitro biomineralization. Further in vivo study demonstrates the improved bone growth around PDA@DH/PLGA over DH/PLGA after 20 days of drug release. The dual functional PDA@DH/PLGA scaffold shows great promise in the treatment of bone tumor.

Stand-Alone CuFeSe2 (Eskebornite) Nanosheets for Photothermal Cancer Therapy

Two-dimensional CuFeSe2 nanosheets have been successfully obtained via solution-phase synthesis using a sacrificial template method. The high purity was confirmed by X-ray diffraction and the two-dimensional morphology was validated by transmission electron microscopy. The intense absorption in the 400-1400 nm region has been the basis for the CuFeSe2 nanosheets' photothermal capabilities testing. The colloidal CuFeSe2 (CFS) nanosheets capped with S2- short ligands (CFS-S) exhibit excellent biocompatibility in cell culture studies and strong photothermal effects upon 808 nm laser irradiation. The nanosheets were further loaded with the cancer drug doxorubicin and exposed to laser irradiation, which accelerated the release of doxorubicin, achieving synergy in the therapeutic effect.

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.