Using scaffolds as drug delivery systems to treat bone tumor

Polydopamine-functionalized calcium-deficient hydroxyapatite 3D-printed scaffold with sustained doxorubicin release for synergistic chemo-photothermal therapy of osteosarcoma and accelerated bone regeneration

Interior bone-tissue regeneration and rapid tumor recurrence post-resection are critical challenges in osteosarcoma and other bone cancers. Conventional bone tissue engineering scaffolds lack inhibitory effects on bone tumor recurrence. Herein, multifunctional scaffolds (named DOX/PDA@CDHA) were designed through the spontaneous polymerization of Dopamine (PDA) on the surface of Calcium Deficient Hydroxyapatite (CDHA) scaffolds, followed by in situ loading of the chemotherapeutic drug Doxorubicin (DOX). The PDA coating endowed the scaffolds with significant photothermal properties, while the gradual release of DOX provided an effective chemotherapeutic effect. The on-demand release of DOX at tumor sites, triggered by dual stimulation (near-infrared (NIR) light and the acidic pH typical of tumor microenvironments), specifically targets cancer cells, thereby mitigating systemic side effects. These unique characteristics facilitated effective osteosarcoma eradication both in vitro and in vivo. Moreover, the scaffold's composition, which mimics the mineral phase of natural bone and is enhanced by PDA's biocompatibility, promotes critical osteogenic and angiogenic processes. This facilitates not only tumor eradication but also the regeneration of healthy bone tissue. Collectively, this study presents a potent candidate for the regeneration of bone defects induced by osteosarcoma.

Emerging Bioprinting for Wound Healing

Bioprinting has attracted much attention due to its suitability for fabricating biomedical devices. In particular, bioprinting has become one of the growing centers in the field of wound healing, with various types of bioprinted devices being developed, including 3D scaffolds, microneedle patches, and flexible electronics. Bioprinted devices can be designed with specific biostructures and biofunctions that closely match the shape of wound sites and accelerate the regeneration of skin through various approaches. Herein, a comprehensive review of the bioprinting of smart wound dressings is presented, emphasizing the crucial effect of bioprinting in determining biostructures and biofunctions. The review begins with an overview of bioprinting techniques and bioprinted devices, followed with an in-depth discussion of polymer-based inks, modification strategies, additive ingredients, properties, and applications. The strategies for the modification of bioprinted devices are divided into seven categories, including chemical synthesis of novel inks, physical blending, coaxial bioprinting, multimaterial bioprinting, physical absorption, chemical immobilization, and hybridization with living cells, and examples are presented. Thereafter, the frontiers of bioprinting and wound healing, including 4D bioprinting, artificial intelligence-assisted bioprinting, and in situ bioprinting, are discussed from a perspective of interdisciplinary sciences. Finally, the current challenges and future prospects in this field are highlighted.

PLGA-based drug delivery systems in treating bone tumors

Bone tumor has become a common disease that endangers human health. Surgical resection of bone tumors not only causes biomechanical defects of bone but also destroys the continuity and integrity of bone and cannot completely remove the local tumor cells. The remaining tumor cells in the lesion bring a hidden danger of local recurrence. To improve the chemotherapeutic effect and effectively clear tumor cells, traditional systemic chemotherapy often requires higher doses, and high doses of chemotherapeutic drugs inevitably cause a series of systemic toxic side effects, often intolerable to patients. PLGA-based drug delivery systems, such as nano delivery systems and scaffold-based local delivery systems, can help eliminate tumors and promote bone regeneration and therefore have more significant potential for application in bone tumor treatment. In this review, we summarize the research progress of PLGA nano drug delivery systems and PLGA scaffold-based local delivery systems in bone tumor treatment applications, expecting to provide a theoretical basis for developing novel bone tumor treatment strategies.

Janus-Inspired Core-Shell Structure Hydrogel Programmatically Releases Melatonin for Reconstruction of Postoperative Bone Tumor

At present, surgery is one of the main treatments for bone tumor. However, the risk of recurrence and the large area of bone defects after surgery pose a great challenge. Therefore, a Janus-inspired core-shell structure bone scaffold was designed to achieve the self-programmed release of melatonin at different concentrations, clearing the residual tumor cells at early stage after resection and promoting bone repair later. The layered differential load designs inspired by Janus laid the foundation for the differential release of melatonin, where sufficient melatonin inhibited tumor growth as low dose promoted osteogenesis. Then, the automatically programmed delivery of melatonin is achieved by the gradient degradation of the core-shell structure. In the material characterization, scanning electron microscopy revealed the core-shell structure. The drug release experiment and in vivo degradation experiment reflected the programmed differential release of melatonin. In the biological experiment part, in vivo and in vitro experiments not only confirmed the significant inhibitory effect of the core-shell hydrogel scaffold on tumor but also confirmed its positive effect on osteogenesis. Our Janus-inspired core-shell hydrogel scaffold provides a safe and efficient means to inhibit tumor recurrence and bone repair after bone tumor, and it also develops a new and efficient tool for differential and programmed release of other drugs.

Current and Emerging Approaches for Spine Tumor Treatment

Spine tumors represent a significant social and medical problem, affecting the quality of life of thousands of patients and imposing a burden on healthcare systems worldwide. Encompassing a wide range of diseases, spine tumors require prompt multidisciplinary treatment strategies, being mainly approached through chemotherapy, radiotherapy, and surgical interventions, either alone or in various combinations. However, these conventional tactics exhibit a series of drawbacks (e.g., multidrug resistance, tumor recurrence, systemic adverse effects, invasiveness, formation of large bone defects) which limit their application and efficacy. Therefore, recent research focused on finding better treatment alternatives by utilizing modern technologies to overcome the challenges associated with conventional treatments. In this context, the present paper aims to describe the types of spine tumors and the most common current treatment alternatives, further detailing the recent developments in anticancer nanoformulations, personalized implants, and enhanced surgical techniques.

Smart-Temporary-Film-Based Local-Delivery System with Controllable Drug-Release Behavior

The development of a simple local drug-delivery system that exhibits the advantages of macro- and microscale carriers with controllable drug-release behavior is still highly desired. Herein, in this work, a smart temporary film was prepared from doxorubicin (DOX)-loaded shape-memory microgels via a simple hot-compression programming method. The temporary film showed a very smooth surface and easy handing, as well as macroscopy mechanical properties, which could disintegrate into the microgels with heating at 45 °C. In this case, the temporary film showed a controllable DOX release behavior when compared with the microgels, which could release the DOX on demand. Consequently, the temporary film exhibited weaker cytotoxicity to normal cells and a much longer antitumor capability, as well as a higher drug-utilization efficiency when compared with microgels. Therefore, the smart temporary film has high potential as a candidate for use as a local drug-delivery system.

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.