Drug Delivery Applications of Three-Dimensional Printed (3DP) Mesoporous Scaffolds

Osteogenic Evaluation of 3D-printed PLA scaffolds Integrated with Khellin-loaded Chitosan-Alginate Sponges for Bone Tissue Engineering

Bone tissue engineering (BTE) offers promising strategies for bone regeneration, yet the effective delivery of bioactive molecules remains a challenge. Khellin (KH), a plant-derived furanochromone, possesses various biological properties, though its potential in promoting osteogenesis has not been thoroughly investigated. In this study, 3D-printed polylactic acid (PLA) scaffolds were integrated with KH-loaded chitosan-alginate sponges (PLA/ALG/CS-KH) to facilitate controlled and sustained delivery of KH. Using sol-gel and freeze-drying techniques, KH was incorporated at varying concentrations (60, 70, and 80 μM) to enhance its bioavailability. Comprehensive physicochemical analyses demonstrated that KH incorporation did not alter the scaffolds' porosity, swelling capacity, protein adsorption, degradation rates, or biomineralization potential. In vitro studies revealed that the PLA/ALG/CS-KH scaffolds were biocompatible with mesenchymal stem cells and effectively promoted osteogenic differentiation, particularly at a concentration of 70 μM KH. These results suggest that PLA/ALG/CS-KH scaffolds have significant potential as osteoinductive platforms for BTE applications, providing a novel approach for enhancing bone regeneration through the sustained release of KH.

Redefining Medical Applications with Safe and Sustainable 3D Printing

Additive manufacturing (AM) has revolutionized biomedical applications by enabling personalized designs, intricate geometries, and cost-effective solutions. This progress stems from interdisciplinary collaborations across medicine, biomaterials, engineering, artificial intelligence, and microelectronics. A pivotal aspect of AM is the development of materials that respond to stimuli such as heat, light, moisture, and chemical changes, paving the way for intelligent systems tailored to specific needs. Among the materials employed in AM, polymers have gained prominence due to their flexibility, synthetic versatility, and broad property spectrum. Their adaptability has made them the most widely used material class in AM processes, offering the potential for diverse applications, including surgical tools, structural composites, photovoltaic devices, and filtration systems. Despite this, integrating multiple polymer systems to achieve multifunctional and dynamic performance remains a significant challenge, highlighting the need for further research. This review explores the foundational principles of AM, emphasizing its application in tissue engineering and medical technologies. It provides an in-depth analysis of polymer systems, besides inorganic oxides and bioinks, and examines their unique properties, advantages, and limitations within the context of AM. Additionally, the review highlights emerging techniques like rapid prototyping and 3D printing, which hold promise for advancing biomedical applications. By addressing the critical factors influencing AM processes and proposing innovative approaches to polymer integration, this review aims to guide future research and development in the field. The insights presented here underscore the transformative potential of AM in creating dynamic, multifunctional systems to meet evolving biomedical and healthcare demands.

3D printing of drug delivery systems enhanced with micro/nano-technology

Drug delivery systems (DDSs) are increasingly important in ensuring drug safety and enhancing therapeutic efficacy. Micro/nano-technology has been utilized to develop DDSs for achieving high stability, bioavailability, and drug efficiency, as well as targeted delivery; meanwhile, 3D printing technology has made it possible to tailor DDSs with diverse components and intricate structures. This review presents the latest research progress integrating 3D printing technology and micro/nano-technology for developing novel DDSs. The technological fundamentals of 3D printing technology supporting the development of DDSs are presented, mainly from the perspective of different 3D printing mechanisms. Distinct types of DDSs leveraging 3D printing and micro/nano-technology are analyzed deeply, featuring micro/nanoscale materials and structures to enrich functionalities and improve effectiveness. Finally, we will discuss the future directions of 3D-printed DDSs integrated with micro/nano-technology, focusing on technological innovation and clinical application. This review will support interdisciplinary research efforts to advance drug delivery technology.

Shape/properties collaborative intelligent manufacturing of artificial bone scaffold: structural design and additive manufacturing process

Artificial bone graft stands out for avoiding limited source of autograft as well as susceptibility to infection of allograft, which makes it a current research hotspot in the field of bone defect repair. However, traditional design and manufacturing method cannot fabricate bone scaffold that well mimics complicated bone-like shape with interconnected porous structure and multiple properties akin to human natural bone. Additive manufacturing, which can achieve implant's tailored external contour and controllable fabrication of internal microporous structure, is able to form almost any shape of designed bone scaffold via layer-by-layer process. As additive manufacturing is promising in building artificial bone scaffold, only combining excellent structural design with appropriate additive manufacturing process can produce bone scaffold with ideal biological and mechanical properties. In this article, we sum up and analyze state of art design and additive manufacturing methods for bone scaffold to realize shape/properties collaborative intelligent manufacturing. Scaffold design can be mainly classified into design based on unit cells and whole structure, while basic additive manufacturing and 3D bioprinting are the recommended suitable additive manufacturing methods for bone scaffold fabrication. The challenges and future perspectives in additive manufactured bone scaffold are also discussed.

Drug delivery strategies through 3D-printed calcium phosphate

3D printing has revolutionized bone tissue engineering (BTE) by enabling the fabrication of patient- or defect-specific scaffolds to enhance bone regeneration. The superior biocompatibility, customizable bioactivity, and biodegradability have enabled calcium phosphate (CaP) to gain significance as a bone graft material. 3D-printed (3DP) CaP scaffolds allow precise drug delivery due to their porous structure, adaptable structure-property relationship, dynamic chemistry, and controlled dissolution. The effectiveness of conventional scaffold-based drug delivery is hampered by initial burst release and drug loss. This review summarizes different multifunctional drug delivery approaches explored in controlling drug release, including polymer coatings, formulation integration, microporous scaffold design, chemical crosslinking, and direct extrusion printing for BTE applications. The review also outlines perspectives and future challenges in drug delivery research, paving the way for next-generation bone repair methodologies.

Silica 3D printed scaffolds as pH stimuli-responsive drug release platform

Silica-based scaffolds are promising in Tissue Engineering by enabling personalized scaffolds, boosting exceptional bioactivity and osteogenic characteristics. Moreover, silica materials are highly tunable, allowing for controlled drug release to enhance tissue regeneration. In this study, we developed a 3D printable silica material with controlled mesoporosity, achieved through the sol-gel reaction of tetraethyl orthosilicate (TEOS) at mild temperatures with the addition of different calcium concentrations. The resultant silica inks exhibited high printability and shape fidelity, while maintaining bioactivity and biocompatibility. Notably, the increased mesopore size enhanced the incorporation and release of large molecules, using cytochrome C as a drug model. Due to the varying surface charge of silica depending on the pH, a pH-dependent control release was obtained between pH 2.5 and 7.5, with maximum release in acidic conditions. Therefore, silica with controlled mesoporosity could be 3D printed, acting as a pH stimuli responsive platform with therapeutic potential.

An update on the advances in the field of nanostructured drug delivery systems for a variety of orthopedic applications

Nanotechnology has made significant progress in various fields, including medicine, in recent times. The application of nanotechnology in drug delivery has sparked a lot of research interest, especially due to its potential to revolutionize the field. Researchers have been working on developing nanomaterials with distinctive characteristics that can be utilized in the improvement of drug delivery systems (DDS) for the local, targeted, and sustained release of drugs. This approach has shown great potential in managing diseases more effectively with reduced toxicity. In the medical field of orthopedics, the use of nanotechnology is also being explored, and there is extensive research being conducted to determine its potential benefits in treatment, diagnostics, and research. Specifically, nanophase drug delivery is a promising technique that has demonstrated the capability of delivering medications on a nanoscale for various orthopedic applications. In this article, we will explore current advancements in the area of nanostructured DDS for orthopedic use.

3D-printed hydroxyapatite scaffolds for bone tissue engineering: A systematic review in experimental animal studies

The use of 3D-printed hydroxyapatite (HA) scaffolds for stimulating bone healing has been increasing over the years. Although all the promising effects of these scaffolds, there are still few studies and limited understanding of their interaction with bone tissue and their effects on the process of fracture healing. In this context, this study aimed to perform a systematic literature review examining the effects of different 3D-printed HA scaffolds in bone healing. The search was made according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA) orientations and Medical Subject Headings (MeSH) descriptors "3D printing," "bone," "HA," "repair," and "in vivo." Thirty-six articles were retrieved from PubMed and Scopus databases. After eligibility analyses, 20 papers were included (covering the period of 2016 and 2021). Results demonstrated that all the studies included in this review showed positive outcomes, indicating the efficacy of scaffolds treated groups in the in vivo experiments for promoting bone healing in different animal models. In conclusion, 3D-printed HA scaffolds are excellent candidates as bone grafts due to their bioactivity and good bone interaction.

Highly porous bio-glass scaffolds fabricated by polyurethane template method with hydrothermal treatment for tissue engineering uses

Objectives

Bioglass scaffolds, which contain a significant percentage of porosity for tissue engineering purposes, have low strength. For increasing the strength and efficiency of such structures for use in tissue engineering, fabrication of hierarchical meso/macro-porous bioglass scaffolds, developing their mechanical strength by hydrothermal treatment and adjusting pH method, and achieving the appropriate mesopore size for loading large biomolecules, were considered in this study.

Materials and Methods

Mesoporous bioglass (MBG) powders were synthesized using cetyltrimethylammonium bromide as a surfactant, with different amounts of calcium sources to obtain the appropriate size of the mesoporous scaffolds. Then MBG scaffolds were fabricated by a polyurethane foam templating method, and for increasing scaffold strength hydrothermal treatment (90 ^°C, for 5 days) and adjustment pH (pH=9) method was used to obtain hierarchical meso/macro-porous structures. The sample characterization was done by Simultaneous thermal analysis, Fourier transform infrared spectroscopy, Field Emission Scanning electron microscopy, small and wide-angle X-ray powder diffractions, transmission electron microscopy, and analysis of nitrogen adsorption-desorption isotherm. The mechanical strength of scaffolds was also determined.

Results

The MBG scaffolds based on 80.28 (wt.) % SiO₂- 17.89 (wt.) % CaO- 1.81 (wt.) % P₂O₅ presented interconnected large pores and pores in the range of 100-150 μm and 6-18 nm, respectively and 0.4 MPa compressive strength.

Conclusion

The total pore volume and specific surface area were obtained from the Brunauer-Emmett-Teller theory, 0.709 cm³ g^-1 and 213.83 m² g^-1, respectively. These findings could be considered in bone-cartilage tissue engineering.

Recent Advances in 3D Bioprinting: A Review of Cellulose-Based Biomaterials Ink

Cellulose-based biodegradable hydrogel proves to be excellently suitable for the medical and water treatment industry based on the expressed properties such as its flexible structure and broad compatibility. Moreover, their potential to provide excellent waste management from the unutilized plant has triggered further study on the advanced biomaterial applications. To extend the use of cellulose-based hydrogel, additive manufacturing is a suitable technique for hydrogel fabrication in complex designs. Cellulose-based biomaterial ink used in 3D bioprinting can be further used for tissue engineering, drug delivery, protein study, microalgae, bacteria, and cell immobilization. This review includes a discussion on the techniques available for additive manufacturing, bio-based material, and the formation of a cellulose-based hydrogel.

Micro/Nanosystems for Magnetic Targeted Delivery of Bioagents

Targeted delivery of pharmaceuticals is promising for efficient disease treatment and reduction in adverse effects. Nano or microstructured magnetic materials with strong magnetic momentum can be noninvasively controlled via magnetic forces within living beings. These magnetic carriers open perspectives in controlling the delivery of different types of bioagents in humans, including small molecules, nucleic acids, and cells. In the present review, we describe different types of magnetic carriers that can serve as drug delivery platforms, and we show different ways to apply them to magnetic targeted delivery of bioagents. We discuss the magnetic guidance of nano/microsystems or labeled cells upon injection into the systemic circulation or in the tissue; we then highlight emergent applications in tissue engineering, and finally, we show how magnetic targeting can integrate with imaging technologies that serve to assist drug delivery.

Three-Dimensional Silk Fibroin/Chitosan Based Microscaffold for Anticancer Drug Screening

Traditional monolayer cell cultures often fail to accurately predict the anticancer activity of drug candidates, as they do not recapitulate the natural microenvironment. Recently, three-dimensional (3D) culture systems have been increasingly applied to cancer research and drug screening. Materials with good biocompatibility are crucial to create a 3D tumor microenvironment involved in such systems. In this study, natural silk fibroin (SF) and chitosan (CS) were selected as the raw materials to fabricate 3D microscaffolds; Besides, sodium tripolyphosphate (TPP), and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) were used as cross-linking agents. The physicochemical properties of obtained scaffolds were characterized with kinds of testing methods, including emission scanning electron microscopy, x-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, water absorption, and swelling ratio analysis. Cancer cell lines (LoVo and MDA-MB-231) were then seeded on scaffolds for biocompatibility examination and drug sensitivity tests. SEM results showed that EDC cross-linked scaffolds had smaller and more uniform pores with great interconnection than the TPP cross-linked scaffolds, and the EDC cross-linked scaffold exhibited a water absorption ratio around 1000% and a swelling ratio of about 72%. These spatial structures and physical properties could provide more adhesion sites and sufficient nutrients for cell growth. Moreover, both LoVo and MDA-MB-231 cells cultured on the EDC cross-linked scaffold exhibited good adhesion and spreading. CCK8 results showed that increased chemotherapeutic drug sensitivity was observed in 3D culture compared with 2D culture, particularly in the condition of low drug dose (<1  μ M). The proposed SF/CS microscaffold can provide a promising in vitro platform for the efficacy prediction and sensitivity screening of anticancer drugs.

Ion-doped mesoporous bioactive glass: preparation, characterization, and applications using the spray pyrolysis method

Biotechnology is used extensively in medical procedures, dentistry, statures, biosensors, bio electrodes, skin substitutes, and medicine delivery systems. Glass is biocompatible and can be used in permanent implantation applications without risk. The porosity of BG matrixes, combined with their huge specific surface area, greatly aids the formation of hydroxyl carbonate apatite. Zn-Doped bioglass can be made in the lab in a variety of ways, depending on how it will be used in medical treatment. The melt-quenching technique, spray pyrolysis method, sol-gel process for BG fabrication, spray drying method, and modified Stöber method are examples of such strategies. Spray pyrolysis is a comprehensive approach that is an undeniably versatile and effective material synthesis technology. It is a low-cost, non-vacuum method for producing materials in the form of powders and films that may be deposited on a variety of substrates, and is a straightforward method to adapt for large-area deposition and industrial production processes. For better utility in medical care, MBG fabricated in the laboratory should be characterized using various characterization methods such as SEM, TEM, BET, and XRD.

3D-Printed Degradable Anti-Tumor Scaffolds for Controllable Drug Delivery

In this study, porous polylactic acid/methotrexate (PLA/MTX) scaffolds were successfully fabricated by three-dimensional (3D) printing technology as controllable drug delivery devices to suppress tumor growth. Scanning electron microscopy and energy-dispersive spectrometer confirmed that MTX drug was successfully incorporated into the PLA filament. 3D-printed PLA/MTX scaffolds allow sustained release of drug molecules in vitro for more than 30 days, reducing systemic toxic side effects caused by injection or oral administration. In vitro cytotoxicity assay revealed that PLA/MTX scaffolds have a relatively high inhibitory effect on the tumor cells (MG-63, A549, MCF-7, and 4T1) and relatively low toxic effect on the normal MC3T3-E1 cells. Furthermore, results of in vivo experiments confirmed that PLA/MTX scaffolds highly suppressed tumor growth and no obvious side effects on the organs. All these results suggested that 3D-printed PLA/MTX scaffolds could be used as controllable drug delivery systems for tumor suppression.

Opportunities and challenges of three-dimensional printing technology in pharmaceutical formulation development

Three-dimensional printing is a technology that prints the products layer-by-layer, in which materials are deposited according to the digital model designed by computer aided design (CAD) software. This technology has competitive advantages regarding product design complexity, product personalization, and on-demand manufacturing. The emergence of 3D technology provides innovative strategies and new ways to develop novel drug delivery systems. This review summarizes the application of 3D printing technologies in the pharmaceutical field, with an emphasis on the advantages of 3D printing technologies for achieving rapid drug delivery, personalized drug delivery, compound drug delivery and customized drug delivery. In addition, this article illustrates the limitations and challenges of 3D printing technologies in the field of pharmaceutical formulation development.

Additive Manufacturing of Polymer Materials: Progress, Promise and Challenges

The use of additive manufacturing (AM) has moved well beyond prototyping and has been established as a highly versatile manufacturing method with demonstrated potential to completely transform traditional manufacturing in the future. In this paper, a comprehensive review and critical analyses of the recent advances and achievements in the field of different AM processes for polymers, their composites and nanocomposites, elastomers and multi materials, shape memory polymers and thermo-responsive materials are presented. Moreover, their applications in different fields such as bio-medical, electronics, textiles, and aerospace industries are also discussed. We conclude the article with an account of further research needs and future perspectives of AM process with polymeric materials.

Calcium Phosphate Modified with Silicon vs. Bovine Hydroxyapatite for Alveolar Ridge Preservation: Densitometric Evaluation, Morphological Changes and Histomorphometric Study

After tooth extraction, the alveolar bone undergoes a physiological resorption that may compromise the future placement of the implant in its ideal position. This study evaluated bone density, morphological changes, and histomorphometric results undergone by alveolar bone after applying a new biomaterial composed of calcium phosphate modified with silicon (CAPO-Si) compared with hydroxyapatite of bovine origin (BHA). Alveolar ridge preservation (ARP) was performed in 24 alveoli, divided into a test group filled with CAPO-Si and a control group filled with BHA. Three months later, the mineral bone density obtained by the biomaterials, horizontal and vertical bone loss, the degree of alveolar corticalization, and histomorphometric results were evaluated. Both biomaterials presented similar behavior in terms of densitometric results, vertical bone loss, and degree of alveolar corticalization. Alveoli treated with CAPO-Si showed less horizontal bone loss in comparison with alveoli treated with BHA (0.99 ± 0.2 mm vs. 1.3 ± 0.3 mm), with statistically significant difference (p = 0.017). Histomorphometric results showed greater bone neoformation in the test group than the control group (23 ± 15% vs. 11 ± 7%) (p = 0.039) and less residual biomaterial (5 ± 10% vs. 17 ± 13%) (p = 0.043) with statistically significant differences. In conclusion, the ARP technique obtains better results with CAPO-Si than with BHA.

Electrodeposited Hydroxyapatite-Based Biocoatings: Recent Progress and Future Challenges

Hydroxyapatite has become an important coating material for bioimplants, following the introduction of synthetic HAp in the 1950s. The HAp coatings require controlled surface roughness/porosity, adequate corrosion resistance and need to show favorable tribological behavior. The deposition rate must be sufficiently fast and the coating technique needs to be applied at different scales on substrates having a diverse structure, composition, size, and shape. A detailed overview of dry and wet coating methods is given. The benefits of electrodeposition include controlled thickness and morphology, ability to coat a wide range of component size/shape and ease of industrial processing. Pulsed current and potential techniques have provided denser and more uniform coatings on different metallic materials/implants. The mechanism of HAp electrodeposition is considered and the effect of operational variables on deposit properties is highlighted. The most recent progress in the field is critically reviewed. Developments in mineral substituted and included particle, composite HAp coatings, including those reinforced by metallic, ceramic and polymeric particles; carbon nanotubes, modified graphenes, chitosan, and heparin, are considered in detail. Technical challenges which deserve further research are identified and a forward look in the field of the electrodeposited HAp coatings is taken.

Nanotechnology-based drug delivery systems in orthopedics

In recent years, nanotechnology has led to significant scientific and technological advances in diverse fields, specifically within the field of medicine. Owing to the revolutionary implications in drug delivery, nanotechnology-based drug delivery systems have gained an increasing research interest in the current medical field. A variety of nanomaterials with unique physical, chemical and biological properties have been engineered to develop new drug delivery systems for the local, sustained and targeted delivery of drugs with improved therapeutic efficiency and less or no toxicity, representing a very promising approach for the effective management of diseases. The utility of nanotechnology, particularly in the field of orthopedics, is a topic of extensive research. Nanotechnology has a great potential to revolutionize treatment, diagnostics, and research in the field of orthopedics. Nanophase drug delivery has shown great promise in their ability to deliver drugs at nanoscale for a variety of orthopedic applications. In this review, we discuss recent advances in the field of nanostructured drug delivery systems for orthopedic applications.