3D-printed magnetic Fe3O4/MBG/PCL composite scaffolds with multifunctionality of bone regeneration, local anticancer drug delivery and hyperthermia

Modeling of Magnetic Scaffolds as Drug Delivery Platforms for Tissue Engineering and Cancer Therapy

Magnetic scaffolds (MagSs) are magneto-responsive devices obtained by the combination of traditional biomaterials (e.g., polymers, bioceramics, and bioglasses) and magnetic nanoparticles. This work analyzes the literature about MagSs used as drug delivery systems for tissue repair and cancer treatment. These devices can be used as innovative drugs and/or biomolecules delivery systems. Through the application of a static or dynamic stimulus, MagSs can trigger drug release in a controlled and remote way. However, most of MagSs used as drug delivery systems are not optimized and properly modeled, causing a local inhomogeneous distribution of the drug's concentration and burst release. Few physical-mathematical models have been presented to study and analyze different MagSs, with the lack of a systematic vision. In this work, we propose a modeling framework. We modeled the experimental data of drug release from different MagSs, under various magnetic field types, taken from the literature. The data were fitted to a modified Gompertz equation and to the Korsmeyer-Peppas model (KPM). The correlation coefficient (R2) and the root mean square error (RMSE) were the figures of merit used to evaluate the fitting quality. It has been found that the Gompertz model can fit most of the drug delivery cases, with an average RMSE below 0.01 and R2>0.9. This quantitative interpretation of existing experimental data can foster the design and use of MagSs for drug delivery applications.

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

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

Recent Advancements in Bone Tissue Engineering: Integrating Smart Scaffold Technologies and Bio-Responsive Systems for Enhanced Regeneration

In exploring the challenges of bone repair and regeneration, this review evaluates the potential of bone tissue engineering (BTE) as a viable alternative to traditional methods, such as autografts and allografts. Key developments in biomaterials and scaffold fabrication techniques, such as additive manufacturing and cell and bioactive molecule-laden scaffolds, are discussed, along with the integration of bio-responsive scaffolds, which can respond to physical and chemical stimuli. These advancements collectively aim to mimic the natural microenvironment of bone, thereby enhancing osteogenesis and facilitating the formation of new tissue. Through a comprehensive combination of in vitro and in vivo studies, we scrutinize the biocompatibility, osteoinductivity, and osteoconductivity of these engineered scaffolds, as well as their interactions with critical cellular players in bone healing processes. Findings from scaffold fabrication techniques and bio-responsive scaffolds indicate that incorporating nanostructured materials and bioactive compounds is particularly effective in promoting the recruitment and differentiation of osteoprogenitor cells. The therapeutic potential of these advanced biomaterials in clinical settings is widely recognized and the paper advocates continued research into multi-responsive scaffold systems.

Engineering mesoporous bioactive glasses for emerging stimuli-responsive drug delivery and theranostic applications

Mesoporous bioactive glasses (MBGs), which belong to the category of modern porous nanomaterials, have garnered significant attention due to their impressive biological activities, appealing physicochemical properties, and desirable morphological features. They hold immense potential for utilization in diverse fields, including adsorption, separation, catalysis, bioengineering, and medicine. Despite possessing interior porous structures, excellent morphological characteristics, and superior biocompatibility, primitive MBGs face challenges related to weak encapsulation efficiency, drug loading, and mechanical strength when applied in biomedical fields. It is important to note that the advantageous attributes of MBGs can be effectively preserved by incorporating supramolecular assemblies, miscellaneous metal species, and their conjugates into the material surfaces or intrinsic mesoporous networks. The innovative advancements in these modified colloidal inorganic nanocarriers inspire researchers to explore novel applications, such as stimuli-responsive drug delivery, with exceptional in-vivo performances. In view of the above, we outline the fabrication process of calcium-silicon-phosphorus based MBGs, followed by discussions on their significant progress in various engineered strategies involving surface functionalization, nanostructures, and network modification. Furthermore, we emphasize the recent advancements in the textural and physicochemical properties of MBGs, along with their theranostic potentials in multiple cancerous and non-cancerous diseases. Lastly, we recapitulate compelling viewpoints, with specific considerations given from bench to bedside.

Chitosan/MWCNTs nanocomposite coating on 3D printed scaffold of poly 3-hydroxybutyrate/magnetic mesoporous bioactive glass: A new approach for bone regeneration

The utilization of 3D printing has become increasingly common in the construction of composite scaffolds. In this study, magnetic mesoporous bioactive glass (MMBG) was incorporated into polyhydroxybutyrate (PHB) to construct extrusion-based 3D printed scaffold. After fabrication of the PHB/MMBG composite scaffolds, they were coated with chitosan (Cs) and chitosan/multi-walled carbon nanotubes (Cs/MWCNTs) solutions utilizing deep coating method. FTIR was conducted to confirm the presence of Cs and MWCNTs on the scaffolds' surface. The findings of mechanical analysis illustrated that presence of Cs/MWCNTs on the composite scaffolds increases compressive young modulus significantly, from 16.5 to 42.2 MPa. According to hydrophilicity evaluation, not only MMBG led to decrease the contact angle of pure PHB but also scaffolds surface modification utilization of Cs and MWCNTs, the contact angle decreased significantly from 82.34° to 54.15°. Furthermore, investigation of cell viability, cell metabolism and inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) and interleukin-10 (IL-10) and transforming growth factor-beta (TGF-β) proved that the scaffolds not only do not stimulate the immune system, but also polarize macrophage cells from M1 phase to M2 phase. The present study highlights the suitability of 3D printed scaffold PHB/MMBG with Cs/MWCNTs coating for bone tissue engineering.

Artificial Intelligence-Based 3D Printing Strategies for Bone Scaffold Fabrication and Its Application in Preclinical and Clinical Investigations

3D printing has become increasingly popular in the field of bone tissue engineering. However, the mechanical properties, biocompatibility, and porosity of the 3D printed bone scaffolds are major requirements for tissue regeneration and implantation as well. Designing the scaffold architecture in accordance with the need to create better mechanical and biological stimuli is necessary to achieve unique scaffold properties. To accomplish this, different 3D designing strategies can be utilized with the help of the scaffold design library and artificial intelligence (AI). The implementation of AI to assist the 3D printing process can enable it to predict, adapt, and control the parameters on its own, which lowers the risk of errors. This Review emphasizes 3D design and fabrication of bone scaffold using different materials and the use of AI-aided 3D printing strategies. Also, the adaption of AI to 3D printing helps to develop patient-specific scaffolds based on different requirements, thus providing feedback and adequate data for reproducibility, which can be improvised in the future. These printed scaffolds can also serve as an alternative to preclinical animal test models to cut costs and prevent immunological interference.

Investigation of background, novelty and recent advance of iron (II,III) oxide- loaded on 3D polymer based scaffolds as regenerative implant for bone tissue engineering: A review

Bone tissue engineering had crucial role in the bone defects regeneration, particularly when allograft and autograft procedures have limitations. In this regard, different types of scaffolds are used in tissue regeneration as fundamental tools. In recent years, magnetic scaffolds show promising applications in different biomedical applications (in vitro and in vivo). As superparamagnetic materials are widely considered to be among the most attractive biomaterials in tissue engineering, due to long-range stability and superior bioactivity, therefore, magnetic implants shows angiogenesis, osteoconduction, and osteoinduction features when they are combined with biomaterials. Furthermore, these scaffolds can be coupled with a magnetic field to enhance their regenerative potential. In addition, magnetic scaffolds can be composed of various combinations of magnetic biomaterials and polymers using different methods to improve the magnetic, biocompatibility, thermal, and mechanical properties of the scaffolds. This review article aims to explain the use of magnetic biomaterials such as iron (II,III) oxide (Fe2O3 and Fe3O4) in detail. So it will cover the research background of magnetic scaffolds, the novelty of using these magnetic implants in tissue engineering, and provides a future perspective on regenerative implants.

Lithiated porous silicon nanowires stimulate periodontal regeneration

Periodontal disease is a significant burden for oral health, causing progressive and irreversible damage to the support structure of the tooth. This complex structure, the periodontium, is composed of interconnected soft and mineralised tissues, posing a challenge for regenerative approaches. Materials combining silicon and lithium are widely studied in periodontal regeneration, as they stimulate bone repair via silicic acid release while providing regenerative stimuli through lithium activation of the Wnt/β-catenin pathway. Yet, existing materials for combined lithium and silicon release have limited control over ion release amounts and kinetics. Porous silicon can provide controlled silicic acid release, inducing osteogenesis to support bone regeneration. Prelithiation, a strategy developed for battery technology, can introduce large, controllable amounts of lithium within porous silicon, but yields a highly reactive material, unsuitable for biomedicine. This work debuts a strategy to lithiate porous silicon nanowires (LipSiNs) which generates a biocompatible and bioresorbable material. LipSiNs incorporate lithium to between 1% and 40% of silicon content, releasing lithium and silicic acid in a tailorable fashion from days to weeks. LipSiNs combine osteogenic, cementogenic and Wnt/β-catenin stimuli to regenerate bone, cementum and periodontal ligament fibres in a murine periodontal defect.

Application of 3D printing technology in tumor diagnosis and treatment

3D printing technology is an increasing approach consisting of material manufacturing through the selective incremental delamination of materials to form a 3D structure to produce products. This technology has different advantages, including low cost, short time, diversification, and high precision. Widely adopted additive manufacturing technologies enable the creation of diagnostic tools and expand treatment options. Coupled with its rapid deployment, 3D printing is endowed with high customizability that enables users to build prototypes in shorts amounts of time which translates into faster adoption in the medical field. This review mainly summarizes the application of 3D printing technology in the diagnosis and treatment of cancer, including the challenges and the prospects combined with other technologies applied to the medical field.

Translational biomaterials of four-dimensional bioprinting for tissue regeneration

Bioprinting is an additive manufacturing technique that combines living cells, biomaterials, and biological molecules to develop biologically functional constructs. Three-dimensional (3D) bioprinting is commonly used as anin vitromodeling system and is a more accurate representation ofin vivoconditions in comparison to two-dimensional cell culture. Although 3D bioprinting has been utilized in various tissue engineering and clinical applications, it only takes into consideration the initial state of the printed scaffold or object. Four-dimensional (4D) bioprinting has emerged in recent years to incorporate the additional dimension of time within the printed 3D scaffolds. During the 4D bioprinting process, an external stimulus is exposed to the printed construct, which ultimately changes its shape or functionality. By studying how the structures and the embedded cells respond to various stimuli, researchers can gain a deeper understanding of the functionality of native tissues. This review paper will focus on the biomaterial breakthroughs in the newly advancing field of 4D bioprinting and their applications in tissue engineering and regeneration. In addition, the use of smart biomaterials and 4D printing mechanisms for tissue engineering applications is discussed to demonstrate potential insights for novel 4D bioprinting applications. To address the current challenges with this technology, we will conclude with future perspectives involving the incorporation of biological scaffolds and self-assembling nanomaterials in bioprinted tissue constructs.

Bioactive Materials for Bone Regeneration: Biomolecules and Delivery Systems

Novel tissue regeneration strategies are constantly being developed worldwide. Research on bone regeneration is noteworthy, as many promising new approaches have been documented with novel strategies currently under investigation. Innovative biomaterials that allow the coordinated and well-controlled repair of bone fractures and bone loss are being designed to reduce the need for autologous or allogeneic bone grafts eventually. The current engineering technologies permit the construction of synthetic, complex, biomimetic biomaterials with properties nearly as good as those of natural bone with good biocompatibility. To ensure that all these requirements meet, bioactive molecules are coupled to structural scaffolding constituents to form a final product with the desired physical, chemical, and biological properties. Bioactive molecules that have been used to promote bone regeneration include protein growth factors, peptides, amino acids, hormones, lipids, and flavonoids. Various strategies have been adapted to investigate the coupling of bioactive molecules with scaffolding materials to sustain activity and allow controlled release. The current manuscript is a thorough survey of the strategies that have been exploited for the delivery of biomolecules for bone regeneration purposes, from choosing the bioactive molecule to selecting the optimal strategy to synthesize the scaffold and assessing the advantages and disadvantages of various delivery strategies.

Recent advances in 3D printing of biodegradable metals for orthopaedic applications

The use of biodegradable polymers for treating bone-related diseases has become a focal point in the field of biomedicine. Recent advancements in material technology have expanded the range of materials suitable for orthopaedic implants. Three-dimensional (3D) printing technology has become prevalent in healthcare, and while organ printing is still in its early stages and faces ethical and technical hurdles, 3D printing is capable of creating 3D structures that are supportive and controllable. The technique has shown promise in fields such as tissue engineering and regenerative medicine, and new innovations in cell and bio-printing and printing materials have expanded its possibilities. In clinical settings, 3D printing of biodegradable metals is mainly used in orthopedics and stomatology. 3D-printed patient-specific osteotomy instruments, orthopedic implants, and dental implants have been approved by the US FDA for clinical use. Metals are often used to provide support for hard tissue and prevent complications. Currently, 70-80% of clinically used implants are made from niobium, tantalum, nitinol, titanium alloys, cobalt-chromium alloys, and stainless steels. However, there has been increasing interest in biodegradable metals such as magnesium, calcium, zinc, and iron, with numerous recent findings. The advantages of 3D printing, such as low manufacturing costs, complex geometry capabilities, and short fabrication periods, have led to widespread adoption in academia and industry. 3D printing of metals with controllable structures represents a cutting-edge technology for developing metallic implants for biomedical applications. This review explores existing biomaterials used in 3D printing-based orthopedics as well as biodegradable metals and their applications in developing metallic medical implants and devices. The challenges and future directions of this technology are also discussed.

On the Evaluation of the Hyperthermic Efficiency of Magnetic Scaffolds

Goal: Deep-seated tumors (DST) can be treated using thermoseeds exposed to a radiofrequency magnetic field for performing local interstitial hyperthermia treatment (HT). Several research efforts were oriented to the manufacturing of novel biocompatible magnetic nanostructured thermo-seeds, called magnetic scaffolds (MagS). Several iron-doped bioceramics or magnetic polymers in various formulations are available. However, the crucial evaluation of their heating potential has been carried out with significantly different, lab specific, variable experimental conditions and protocols often ignoring the several error sources and inaccuracies estimation. Methods: This work comments and provides a perspective analysis of an experimental protocol for the estimation methodology of the specific absorption rate (SAR) of MagS for DST HT. Numerical multiphysics simultions have been performed to outline the theoretical framework. After the in silico analysis, an experimental case is considered and tested. Results: From the simulations, we found that large overestimation in the SAR values can be found, due to the axial misplacement in the radiofrequency coil, while the radial misplacement has a lower impact on the estimated SAR value. Conclusions: The averaging of multiple temperature records is needed to reliably and effectively estimate the SAR of MagS for DST HT.

A review on the effect of nanocomposite scaffolds reinforced with magnetic nanoparticles in osteogenesis and healing of bone injuries

Many problems related to disorders and defects of bone tissue caused by aging, diseases, and injuries have been solved by the multidisciplinary research field of regenerative medicine and tissue engineering. Numerous sciences, especially nanotechnology, along with tissue engineering, have greatly contributed to the repair and regeneration of tissues. Various studies have shown that the presence of magnetic nanoparticles (MNPs) in the structure of composite scaffolds increases their healing effect on bone defects. In addition, the induction of osteogenic differentiation of mesenchymal stem cells (MSCs) in the presence of these nanoparticles has been investigated and confirmed by various studies. Therefore, in the present article, the types of MNPs, their special properties, and their application in the healing of damaged bone tissue have been reviewed. Also, the molecular effects of MNPs on cell behavior, especially in osteogenesis, have been discussed. Finally, the present article includes the potential applications of MNP-containing nanocomposite scaffolds in bone lesions and injuries. In summary, this review article highlights nanocomposite scaffolds containing MNPs as a solution for treating bone defects in tissue engineering and regenerative medicine.

Machine Learning in Predicting Printable Biomaterial Formulations for Direct Ink Writing

Three-dimensional (3D) printing is emerging as a transformative technology for biomedical engineering. The 3D printed product can be patient-specific by allowing customizability and direct control of the architecture. The trial-and-error approach currently used for developing the composition of printable inks is time- and resource-consuming due to the increasing number of variables requiring expert knowledge. Artificial intelligence has the potential to reshape the ink development process by forming a predictive model for printability from experimental data. In this paper, we constructed machine learning (ML) algorithms including decision tree, random forest (RF), and deep learning (DL) to predict the printability of biomaterials. A total of 210 formulations including 16 different bioactive and smart materials and 4 solvents were 3D printed, and their printability was assessed. All ML methods were able to learn and predict the printability of a variety of inks based on their biomaterial formulations. In particular, the RF algorithm has achieved the highest accuracy (88.1%), precision (90.6%), and F1 score (87.0%), indicating the best overall performance out of the 3 algorithms, while DL has the highest recall (87.3%). Furthermore, the ML algorithms have predicted the printability window of biomaterials to guide the ink development. The printability map generated with DL has finer granularity than other algorithms. ML has proven to be an effective and novel strategy for developing biomaterial formulations with desired 3D printability for biomedical engineering applications.

Recent advances on 3D-printed PCL-based composite scaffolds for bone tissue engineering

Population ageing and various diseases have increased the demand for bone grafts in recent decades. Bone tissue engineering (BTE) using a three-dimensional (3D) scaffold helps to create a suitable microenvironment for cell proliferation and regeneration of damaged tissues or organs. The 3D printing technique is a beneficial tool in BTE scaffold fabrication with appropriate features such as spatial control of microarchitecture and scaffold composition, high efficiency, and high precision. Various biomaterials could be used in BTE applications. PCL, as a thermoplastic and linear aliphatic polyester, is one of the most widely used polymers in bone scaffold fabrication. High biocompatibility, low cost, easy processing, non-carcinogenicity, low immunogenicity, and a slow degradation rate make this semi-crystalline polymer suitable for use in load-bearing bones. Combining PCL with other biomaterials, drugs, growth factors, and cells has improved its properties and helped heal bone lesions. The integration of PCL composites with the new 3D printing method has made it a promising approach for the effective treatment of bone injuries. The purpose of this review is give a comprehensive overview of the role of printed PCL composite scaffolds in bone repair and the path ahead to enter the clinic. This study will investigate the types of 3D printing methods for making PCL composites and the optimal compounds for making PCL composites to accelerate bone healing.

Additive manufacturing of sustainable biomaterials for biomedical applications

Biopolymers are promising environmentally benign materials applicable in multifarious applications. They are especially favorable in implantable biomedical devices thanks to their excellent unique properties, including bioactivity, renewability, bioresorbability, biocompatibility, biodegradability and hydrophilicity. Additive manufacturing (AM) is a flexible and intricate manufacturing technology, which is widely used to fabricate biopolymer-based customized products and structures for advanced healthcare systems. Three-dimensional (3D) printing of these sustainable materials is applied in functional clinical settings including wound dressing, drug delivery systems, medical implants and tissue engineering. The present review highlights recent advancements in different types of biopolymers, such as proteins and polysaccharides, which are employed to develop different biomedical products by using extrusion, vat polymerization, laser and inkjet 3D printing techniques in addition to normal bioprinting and four-dimensional (4D) bioprinting techniques. This review also incorporates the influence of nanoparticles on the biological and mechanical performances of 3D-printed tissue scaffolds. This work also addresses current challenges as well as future developments of environmentally friendly polymeric materials manufactured through the AM techniques. Ideally, there is a need for more focused research on the adequate blending of these biodegradable biopolymers for achieving useful results in targeted biomedical areas. We envision that biopolymer-based 3D-printed composites have the potential to revolutionize the biomedical sector in the near future.

A Review of Biomimetic and Biodegradable Magnetic Scaffolds for Bone Tissue Engineering and Oncology

Bone defects characterized by limited regenerative properties are considered a priority in surgical practice, as they are associated with reduced quality of life and high costs. In bone tissue engineering, different types of scaffolds are used. These implants represent structures with well-established properties that play an important role as delivery vectors or cellular systems for cells, growth factors, bioactive molecules, chemical compounds, and drugs. The scaffold must provide a microenvironment with increased regenerative potential at the damage site. Magnetic nanoparticles are linked to an intrinsic magnetic field, and when they are incorporated into biomimetic scaffold structures, they can sustain osteoconduction, osteoinduction, and angiogenesis. Some studies have shown that combining ferromagnetic or superparamagnetic nanoparticles and external stimuli such as an electromagnetic field or laser light can enhance osteogenesis and angiogenesis and even lead to cancer cell death. These therapies are based on in vitro and in vivo studies and could be included in clinical trials for large bone defect regeneration and cancer treatments in the near future. We highlight the scaffolds' main attributes and focus on natural and synthetic polymeric biomaterials combined with magnetic nanoparticles and their production methods. Then, we underline the structural and morphological aspects of the magnetic scaffolds and their mechanical, thermal, and magnetic properties. Great attention is devoted to the magnetic field effects on bone cells, biocompatibility, and osteogenic impact of the polymeric scaffolds reinforced with magnetic nanoparticles. We explain the biological processes activated due to magnetic particles' presence and underline their possible toxic effects. We present some studies regarding animal tests and potential clinical applications of magnetic polymeric scaffolds.

The diversified hydrogels for biomedical applications and their imperative roles in tissue regeneration

Repair and regeneration of tissues after injury are complex pathophysiological processes. Microbial infection, malnutrition, and an ischemic and hypoxic microenvironment in the injured area can impede the typical healing cascade. Distinguished by biomimicry of the extracellular matrix, high aqueous content, and diverse functions, hydrogels have revolutionized clinical practices in tissue regeneration owing to their outstanding hydrophilicity, biocompatibility, and biodegradability. Various hydrogels such as smart hydrogels, nanocomposite hydrogels, and acellular matrix hydrogels are widely used for applications ranging from bench-scale to an industrial scale. In this review, some emerging hydrogels in the biomedical field are briefly discussed. The protective roles of hydrogels in wound dressings and their diverse biological effects on multiple tissues such as bone, cartilage, nerve, muscle, and adipose tissue are also discussed. The vehicle functions of hydrogels for chemicals and cell payloads are detailed. Additionally, this review emphasizes the particular characteristics of hydrogel products that promote tissue repair and reconstruction such as anti-infection, inflammation regulation, and angiogenesis.

A Review on Manufacturing Processes of Biocomposites Based on Poly(α-Esters) and Bioactive Glass Fillers for Bone Regeneration

The incorporation of bioactive and biocompatible fillers improve the bone cell adhesion, proliferation and differentiation, thus facilitating new bone tissue formation upon implantation. During these last 20 years, those biocomposites have been explored for making complex geometry devices likes screws or 3D porous scaffolds for the repair of bone defects. This review provides an overview of the current development of manufacturing process with synthetic biodegradable poly(α-ester)s reinforced with bioactive fillers for bone tissue engineering applications. Firstly, the properties of poly(α-ester), bioactive fillers, as well as their composites will be defined. Then, the different works based on these biocomposites will be classified according to their manufacturing process. New processing techniques, particularly additive manufacturing processes, open up a new range of possibilities. These techniques have shown the possibility to customize bone implants for each patient and even create scaffolds with a complex structure similar to bone. At the end of this manuscript, a contextualization exercise will be performed to identify the main issues of process/resorbable biocomposites combination identified in the literature and especially for resorbable load-bearing applications.

Biological Scaffolds Assembled with Magnetic Nanoparticles for Bone Tissue Engineering: A Review

Superparamagnetic iron oxide nanoparticles (SPION) are widely used in bone tissue engineering because of their unique physical and chemical properties and their excellent biocompatibility. Under the action of a magnetic field, SPIONs loaded in a biological scaffold can effectively promote osteoblast proliferation, differentiation, angiogenesis, and so on. SPIONs have very broad application prospects in bone repair, bone reconstruction, bone regeneration, and other fields. In this paper, several methods for forming biological scaffolds via the biological assembly of SPIONs are reviewed, and the specific applications of these biological scaffolds in bone tissue engineering are discussed.

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.

3D printing of pharmaceuticals for disease treatment

Three-dimensional (3D) printing or Additive manufacturing has paved the way for developing and manufacturing pharmaceuticals in a personalized manner for patients with high volume and rare diseases. The traditional pharmaceutical manufacturing process involves the utilization of various excipients to facilitate the stages of blending, mixing, pressing, releasing, and packaging. In some cases, these excipients cause serious side effects to the patients. The 3D printing of pharmaceutical manufacturing avoids the need for excessive excipients. The two major components of a 3D printed tablet or dosage form are polymer matrix and drug component alone. Hence the usage of the 3D printed dosage forms for disease treatment will avoid unwanted side effects and provide higher therapeutic efficacy. With respect to the benefits of the 3D printed pharmaceuticals, the present review was constructed by discussing the role of 3D printing in producing formulations of various dosage forms such as fast and slow releasing, buccal delivery, and localized delivery. The dosage forms are polymeric tablets, nanoparticles, scaffolds, and films employed for treating different diseases.

Preparation and In Vitro Characterization of Magnetic CS/PVA/HA/pSPIONs Scaffolds for Magnetic Hyperthermia and Bone Regeneration

Conventional bone cancer treatment often results in unwanted side effects, critical-sized bone defects, and inefficient cancer-cell targeting. Therefore, new approaches are necessary to better address bone cancer treatment and patient's recovery. One solution may reside in the combination of bone regeneration scaffolds with magnetic hyperthermia. By incorporating pristine superparamagnetic iron oxide nanoparticles (pSPIONs) into additively manufactured scaffolds we created magnetic structures for magnetic hyperthermia and bone regeneration. For this, hydroxyapatite (HA) particles were integrated in a polymeric matrix composed of chitosan (CS) and poly (vinyl alcohol) (PVA). Once optimized, pSPIONs were added to the CS/PVA/HA paste at three different concentrations (1.92, 3.77, and 5.54 wt.%), and subsequently additively manufactured to form a scaffold. Results indicate that scaffolds containing 3.77 and 5.54 wt.% of pSPIONs, attained temperature increases of 6.6 and 7.5 °C in magnetic hyperthermia testing, respectively. In vitro studies using human osteosarcoma Saos-2 cells indicated that pSPIONs incorporation significantly stimulated cell adhesion, proliferation and alkaline phosphatase (ALP) expression when compared to CS/PVA/HA scaffolds. Thus, these results support that CS/PVA/HA/pSPIONs scaffolds with pSPIONs concentrations above or equal to 3.77 wt.% have the potential to be used for magnetic hyperthermia and bone regeneration.

A review on the recent progress, opportunities, and challenges of 4D printing and bioprinting in regenerative medicine

Four-dimensional (4 D) printing is a novel emerging technology, which can be defined as the ability of 3 D printed materials to change their form and functions. The term 'time' is added to 3 D printing as the fourth dimension, in which materials can respond to a stimulus after finishing the manufacturing process. 4 D printing provides more versatility in terms of size, shape, and structure after printing the construct. Complex material programmability, multi-material printing, and precise structure design are the essential requirements of 4 D printing systems. The utilization of stimuli-responsive polymers has increasingly taken the place of cell traction force-dependent methods and manual folding, offering a more advanced technique to affect a construct's adjusted shape transformation. The present review highlights the concept of 4 D printing and the responsive bioinks used in 4 D printing, such as water-responsive, pH-responsive, thermo-responsive, and light-responsive materials used in tissue regeneration. Cell traction force methods are described as well. Finally, this paper aims to introduce the limitations and future trends of 4 D printing in biomedical applications based on selected key references from the last decade.

Bioadhesive Gauze Embedded with Chitosan-Butein Bioconjugate: A Redox-Active pH Sensor Platform

With the ever-growing global wound care market, demand for robust redox-active healthcare material is obvious for the construction of wearable sensor platforms. Surface reactive functional group-rich material like chitosan holds huge potential for electrochemical biosensor application. Herein, a metal-free redox-active chitosan-butein (CSB) bioconjugate is processed into epidermal bioadhesive electrode material useful for pH sensors promising toward wound site analysis. A two-electrode system devised for conducting carbon-reinforced silver chloride paste and CSB-modified carbon/silver chloride matrix was used as a reference and working electrodes, respectively. Dimensions of working and reference electrodes (4 mm) were designed by 2D cutter plotter-assisted stenciling. The cross-sectional topology of the constructed adhesive CSB-sensor platform exhibits an average surface thickness of 183 ± 2 μm. Cyclic voltammetric analysis revealed the inherent 2e^-/2H⁺ transfer attributed to the catechol OH groups of graft polymerized CSB modified on adhesive gauze. As-fabricated modified electrode substrates exhibit distinguishable potential differences with respect to electrolytes of varied pH (between 5 to 9), promising for wound site analysis.

Bioactive Glasses as Carriers of Cancer-Targeted Drugs: Challenges and Opportunities in Bone Cancer Treatment

The treatment of bone cancer involves tumor resection followed by bone reconstruction of the defect caused by the tumor using biomaterials. Additionally, post-surgery protocols cover chemotherapy, radiotherapy, or drug administration, which are employed as adjuvant treatments to prevent tumor recurrence. In this work, we reviewed new strategies for bone cancer treatment based on bioactive glasses as carriers of cancer-targeted and other drugs that are intended for bone regeneration in conjunction with adjuvant treatments. Drugs used in combination with bioactive glasses can be classified into cancer-target, osteoclast-target, and new therapies (such as gene delivery and bioinorganic). Microparticulated, nanoparticulated, or mesoporous bioactive glasses have been used as drug-delivery systems. Additionally, surface modification through functionalization or the production of composites based on polymers and hydrogels has been employed to improve drug-release kinetics. Overall, although different drugs and drug delivery systems have been developed, there is still room for new studies involving kinase inhibitors or antibody-conjugated drugs, as these drugs have been poorly explored in combination with bioactive glasses.

Iron-Based Ceramic Composite Nanomaterials for Magnetic Fluid Hyperthermia and Drug Delivery

Because of the unique physicochemical properties of magnetic iron-based nanoparticles, such as superparamagnetism, high saturation magnetization, and high effective surface area, they have been applied in biomedical fields such as diagnostic imaging, disease treatment, and biochemical separation. Iron-based nanoparticles have been used in magnetic resonance imaging (MRI) to produce clearer and more detailed images, and they have therapeutic applications in magnetic fluid hyperthermia (MFH). In recent years, researchers have used clay minerals, such as ceramic materials with iron-based nanoparticles, to construct nanocomposite materials with enhanced saturation, magnetization, and thermal effects. Owing to their unique structure and large specific surface area, iron-based nanoparticles can be homogenized by adding different proportions of ceramic minerals before and after modification to enhance saturation magnetization. In this review, we assess the potential to improve the magnetic properties of iron-based nanoparticles and in the preparation of multifunctional composite materials through their combination with ceramic materials. We demonstrate the potential of ferromagnetic enhancement and multifunctional composite materials for MRI diagnosis, drug delivery, MFH therapy, and cellular imaging applications.

3D printing hybrid materials using fused deposition modelling for solid oral dosage forms

3D printing in the pharmaceutical and healthcare settings is expanding rapidly, such as the rapid prototyping of orthotics, dental retainers, drug-loaded implants, and pharmaceutical solid oral dosage forms. Through 3D printing, we have the capability to precisely control dose, release kinetics, and several aesthetic features of dosage forms such as colour, shape, and texture. Additionally, polypills can be created with combinations of medications in one solid dosage form at completely customisable strengths that would be extremely difficult to obtain commercially. As the technology and formulations developed through 3D printing are expanding, the development of new hybrid materials to obtain superior formulations are also gaining momentum. In this review we collate data on the importance of developing hybrid formulations of polymers, drugs and excipients necessary to produce reliable and high-quality 3D printed dosage forms with a special emphasis on fused deposition modelling (FDM). FDM technology is one of the most widely used forms of 3D printing and has demonstrated compatibility with unique polymer-based hybrids to allow for enhanced drug delivery, protection of thermolabile drugs, modifiable release kinetics, and more. The data collated covers different categories of hybrids as well as the methods used to fabricate them, and their respective effects on the properties of 3D printed solid oral dosage forms. Therefore, this review will provide an overview of upcoming and emerging trends in pharmaceutical 3D printing formulation compositions.

Thermal Stability of Polycaprolactone Grafted Densely with Maleic Anhydride Analysed Using the Coats-Redfern Equation

The plastic waste problem has recently attracted unprecedented attention globally. To reduce the adverse eff ects on environments, biodegradable polymers have been studied to solve the problems. Poly(ε-caprolactone) (PCL) is one of the common biodegradable plastics used on its own or blended with natural polymers because of its excellent properties after blending. However, PCL and natural polymers are difficult to blend due to the polymers' properties. Grafted polymerization of maleic anhydride and dibenzoyl peroxide (DBPO) with PCL is one of the improvements used for blending immiscible polymers. In this study, we first focused on the effects of three factors (stirring time, maleic anhydride (MA) amount and benzoyl peroxide amount) on the grafting ratio with a maximum value of 4.16% when applying 3.000 g MA and 1.120 g DBPO to 3.375 g PCL with a stirring time of 18 h. After that, the grafting condition was studied based on the kinetic thermal decomposition and activation energy by the Coats-Redfern method. The optimal fitting model was confirmed by the determination coefficient of nearly 1 to explain the contracting volume mechanism of synthesized PCL-g-MA. Consequently, grafted MA hydrophilically augmented PCL as the reduced contact angle of water suggests, facilitating the creation of a plastic-biomaterial composite.

Magnetic 3D-Printed Composites-Production and Applications

Three-dimensional printing enables building objects shaped with a large degree of freedom. Additional functionalities can be included by modifying the printing material, e.g., by embedding nanoparticles in the molten polymer feedstock, the resin, or the solution used for printing, respectively. Such composite materials may be stronger or more flexible, conductive, magnetic, etc. Here, we give an overview of magnetic composites, 3D-printed by different techniques, and their potential applications. The production of the feedstock is described as well as the influence of printing parameters on the magnetic and mechanical properties of such polymer/magnetic composites.

Remotely Temporal Scheduled Macrophage Phenotypic Transition Enables Optimized Immunomodulatory Bone Regeneration

Precise timing of macrophage polarization plays a pivotal role in immunomodulation of tissue regeneration, yet most studies mainly focus on M2 macrophages for their anti-inflammatory and regenerative effects while the essential proinflammatory role of the M1 phenotype on the early inflammation stage is largely underestimated. Herein, a superparamagnetic hydrogel capable of timely controlling macrophage polarization is constructed by grafting superparamagnetic nanoparticles on collagen nanofibers. The magnetic responsive hydrogel network enables efficient polarization of encapsulated macrophage to the M2 phenotype through the podosome/Rho/ROCK mechanical pathway in response to static magnetic field (MF) as needed. Taking advantage of remote accessibility of magnetic field together with the superparamagnetic hydrogels, a temporal engineered M1 to M2 transition course preserving the essential role of M1 at the early stage of tissue healing, as well as enhancing the prohealing effect of M2 at the middle/late stages is established via delayed MF switch. Such precise timing of macrophage polarization matching the regenerative process of injured tissue eventually leads to optimized immunomodulatory bone healing in vivo. Overall, this study offers a remotely time-scheduled approach for macrophage polarization, which enables precise manipulation of inflammation progression during tissue healing.

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.

Direct Ink Writing: A 3D Printing Technology for Diverse Materials

Additive manufacturing (AM) has gained significant attention due to its ability to drive technological development as a sustainable, flexible, and customizable manufacturing scheme. Among the various AM techniques, direct ink writing (DIW) has emerged as the most versatile 3D printing technique for the broadest range of materials. DIW allows printing of practically any material, as long as the precursor ink can be engineered to demonstrate appropriate rheological behavior. This technique acts as a unique pathway to introduce design freedom, multifunctionality, and stability simultaneously into its printed structures. Here, a comprehensive review of DIW of complex 3D structures from various materials, including polymers, ceramics, glass, cement, graphene, metals, and their combinations through multimaterial printing is presented. The review begins with an overview of the fundamentals of ink rheology, followed by an in-depth discussion of the various methods to tailor the ink for DIW of different classes of materials. Then, the diverse applications of DIW ranging from electronics to food to biomedical industries are discussed. Finally, the current challenges and limitations of this technique are highlighted, followed by its prospects as a guideline toward possible futuristic innovations.

Magnetic bioactive glass nano-heterostructures: a deeper insight into magnetic hyperthermia properties in the scope of bone cancer treatment

Primary bone cancers commonly involve surgery to remove the malignant tumor, complemented with a postoperative treatment to prevent cancer resurgence. Studies on magnetic hyperthermia, used as a single treatment or in synergy with chemo- or radiotherapy, have shown remarkable success in the past few decades. Multifunctional biomaterials with bone healing ability coupled with hyperthermia property could thus be of great interest to repair critical bone defects resulting from tumor resection. For this purpose, we designed superparamagnetic and bioactive nanoparticles (NPs) based on iron oxide cores (γ-Fe₂O₃) encapsulated in a bioactive glass (SiO₂-CaO) shell. Nanometric heterostructures (122 ± 12 nm) were obtained through a two-step process: co-precipitation of 16 nm sized iron oxide NPs, followed by the growth of a bioactive glass shell via a modified Stöber method. Their bioactivity was confirmed by hydroxyapatite growth in simulated body fluid, and cytotoxicity assays showed they induced no significant death of human mesenchymal stem cells after 7 days. Calorimetric measurements were carried out under a wide range of alternating magnetic field amplitudes and frequencies, considering clinically relevant parameters, and some were made in viscous medium (agar) to mimic the implantation conditions. The experimental specific loss power was predictable with respect to the Linear Response Theory, and showed a maximal value of 767 ± 77 W g_Fe^-1 (769 kHz, 23.9 kA m^-1 in water). An interesting value of 166 ± 24 W g_Fe^-1 was obtained under clinically relevant conditions (157 kHz, 23.9 kA m^-1) for the heterostructures immobilized in agar. The good biocompatibility, bioactivity and heating ability suggest that these γ-Fe₂O₃@SiO₂-CaO NPs are a promising biomaterial to be used as it is or included in a scaffold to heal bone defects resulting from bone tumor resection.

(Bio)manufactured Solutions for Treatment of Bone Defects with Emphasis on US-FDA Regulatory Science Perspective

Bone defects, with second highest demand for surgeries around the globe, may lead to serious health issues and negatively influence patient lives. The advances in biomedical engineering and sciences have led to the development of several creative solutions for bone defect treatment. This review provides a brief summary of bone graft materials, an organized overview of top-down and bottom-up (bio)manufacturing approaches, plus a critical comparison between advantages and limitations of each method. We specifically discuss additive manufacturing techniques and their operation mechanisms in detail. Next, we review the hybrid methods and promising future directions for bone grafting, while giving a comprehensive US-FDA regulatory science perspective, biocompatibility concepts and assessments, and clinical considerations to translate a technology from a research laboratory to the market. The topics covered in this review could potentially fuel future research efforts in bone tissue engineering, and perhaps could also provide novel insights for other tissue engineering applications.

A Review of 3D Printed Bone Implants

3D printing, that is, additive manufacturing, has solved many major problems in general manufacturing, such as three-dimensional tissue structure, microenvironment control difficulty, product production efficiency and repeatability, etc., improved the manufacturing speed and precision of personalized bone implants, and provided a lot of support for curing patients with bone injuries. The application of 3D printing technology in the medical field is gradually extensive, especially in orthopedics. The purpose of this review is to provide a report on the related achievements of bone implants based on 3D printing technology in recent years, including materials, molding methods, optimization of implant structure and performance, etc., in order to point out the existing shortcomings of 3D printing bone implants, promote the development of all aspects of bone implants, and make a prospect of 4D printing, hoping to provide some reference for the subsequent research of 3D printing bone implants.

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.

Magnetic Nanoparticles in Bone Tissue Engineering

Large bone defects with limited intrinsic regenerative potential represent a major surgical challenge and are associated with a high socio-economic burden and severe reduction in the quality of life. Tissue engineering approaches offer the possibility to induce new functional bone regeneration, with the biomimetic scaffold serving as a bridge to create a microenvironment that enables a regenerative niche at the site of damage. Magnetic nanoparticles have emerged as a potential tool in bone tissue engineering that leverages the inherent magnetism of magnetic nano particles in cellular microenvironments providing direction in enhancing the osteoinductive, osteoconductive and angiogenic properties in the design of scaffolds. There are conflicting opinions and reports on the role of MNPs on these scaffolds, such as the true role of magnetism, the application of external magnetic fields in combination with MNPs, remote delivery of biomechanical stimuli in-vivo and magnetically controlled cell retention or bioactive agent delivery in promoting osteogenesis and angiogenesis. In this review, we focus on the role of magnetic nanoparticles for bone-tissue-engineering applications in both disease modelling and treatment of injuries and disease. We highlight the materials-design pathway from implementation strategy through the selection of materials and fabrication methods to evaluation. We discuss the advances in this field and unmet needs, current challenges in the development of ideal materials for bone-tissue regeneration and emerging strategies in the field.

Recent advances in smart stimuli-responsive biomaterials for bone therapeutics and regeneration

Bone defects combined with tumors, infections, or other bone diseases are challenging in clinical practice. Autologous and allogeneic grafts are two main traditional remedies, but they can cause a series of complications. To address this problem, researchers have constructed various implantable biomaterials. However, the original pathological microenvironment of bone defects, such as residual tumors, severe infection, or other bone diseases, could further affect bone regeneration. Thus, the rational design of versatile biomaterials with integrated bone therapy and regeneration functions is in great demand. Many strategies have been applied to fabricate smart stimuli-responsive materials for bone therapy and regeneration, with stimuli related to external physical triggers or endogenous disease microenvironments or involving multiple integrated strategies. Typical external physical triggers include light irradiation, electric and magnetic fields, ultrasound, and mechanical stimuli. These stimuli can transform the internal atomic packing arrangements of materials and affect cell fate, thus enhancing bone tissue therapy and regeneration. In addition to the external stimuli-responsive strategy, some specific pathological microenvironments, such as excess reactive oxygen species and mild acidity in tumors, specific pH reduction and enzymes secreted by bacteria in severe infection, and electronegative potential in bone defect sites, could be used as biochemical triggers to activate bone disease therapy and bone regeneration. Herein, we summarize and discuss the rational construction of versatile biomaterials with bone therapeutic and regenerative functions. The specific mechanisms, clinical applications, and existing limitations of the newly designed biomaterials are also clarified.

Polymer–Nickel Composite Filaments for 3D Printing of Open Porous Materials

Catalysis has been a key way of improving the efficiency-to-cost ratio of chemical and electrochemical processes. There have been recent developments in catalyst materials that enable the development of novel and more sophisticated devices that, for example, can be used in applications, such as membranes, batteries or fuel cells. Since catalytic reactions occur on the surface, most catalyst materials are based on open porous structures, which facilitates the transport of fluids (gas or liquid) and chemical (or electrochemical) specific surface activity, thus determining the overall efficiency of the device. Noble metals are typically used for low temperature catalysis, whereas lower cost materials, such as nickel, are used for catalysis at elevated temperatures. 3D printing has the potential to produce a more sophisticated fit for purpose catalyst material. This article presents the development, fabrication and performance comparison of three thermoplastic composites where PLA (polylactic acid), PVB (polyvinyl butyral) or ABS (acrylonitrile butadiene styrene) were used as the matrix, and nickel particles were used as filler with various volume fractions, from 5 to 25 vol%. The polymer–metal composites were extruded in the form of filaments and then used for 3D FDM (Fused Deposition Modeling) printing. The 3D printed composites were heat treated to remove the polymer and sinter the nickel particles. 3D printed composites were also prepared using nickel foam as a substrate to increase the final porosity and mechanical strength of the material. The result of the study demonstrates the ability of the optimized filament materials to be used in the fabrication of high open porosity (over 60%) structures that could be used in high-temperature catalysis and/or electrocatalysis.

Natural Fiber-Reinforced Polycaprolactone Green and Hybrid Biocomposites for Various Advanced Applications

Recent developments within the topic of biomaterials has taken hold of researchers due to the mounting concern of current environmental pollution as well as scarcity resources. Amongst all compatible biomaterials, polycaprolactone (PCL) is deemed to be a great potential biomaterial, especially to the tissue engineering sector, due to its advantages, including its biocompatibility and low bioactivity exhibition. The commercialization of PCL is deemed as infant technology despite of all its advantages. This contributed to the disadvantages of PCL, including expensive, toxic, and complex. Therefore, the shift towards the utilization of PCL as an alternative biomaterial in the development of biocomposites has been exponentially increased in recent years. PCL-based biocomposites are unique and versatile technology equipped with several importance features. In addition, the understanding on the properties of PCL and its blend is vital as it is influenced by the application of biocomposites. The superior characteristics of PCL-based green and hybrid biocomposites has expanded their applications, such as in the biomedical field, as well as in tissue engineering and medical implants. Thus, this review is aimed to critically discuss the characteristics of PCL-based biocomposites, which cover each mechanical and thermal properties and their importance towards several applications. The emergence of nanomaterials as reinforcement agent in PCL-based biocomposites was also a tackled issue within this review. On the whole, recent developments of PCL as a potential biomaterial in recent applications is reviewed.

The Tiny Big World of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers: An Updated Review

Nanotechnology is currently a field of endeavor that has reached a maturation phase beyond the initial hypotheses with an undercurrent challenge to optimize the safety, and scalability for production and clinical trials. Lipid-based nanoparticles (LNP), namely solid lipid nanoparticles (SLN) and nanostructured lipid (NLC), carriers are presently among the most attractive and fast-growing areas of research. SLN and NLC are safe, biocompatible nanotechnology-enabled platforms with ubiquitous applications. This review presents a modern vision that starts with a brief description of characteristics, preparation strategies, and composition ingredients, benefits, and limitations. Next, a discussion of applications and functionalization approaches for the delivery of therapeutics via different routes of delivery. Additionally, the review presents a concise perspective into limitations and future advances. A brief recap on the prospects of molecular dynamics simulations in better understanding NP bio-interface interactions is provided. Finally, the alliance between 3D printing and nanomaterials is presented here as well.

3D-Printed Coaxial Hydrogel Patches with Mussel-Inspired Elements for Prolonged Release of Gemcitabine

With the aim of fabricating drug-loaded implantable patches, a 3D printing technique was employed to produce novel coaxial hydrogel patches. The core-section of these patches contained a dopamine-modified methacrylated alginate hydrogel loaded with a chemotherapeutic drug (Gemcitabine), while their shell section was solely comprised of a methacrylated alginate hydrogel. Subsequently, these patches were further modified with CaCO3 cross linker and a polylactic acid (PLA) coating to facilitate prolonged release of the drug. Consequently, the results showed that addition of CaCO3 to the formula enhanced the mechanical properties of the patches and significantly reduced their swelling ratio as compared to that for patches without CaCO3. Furthermore, addition of PLA coating to CaCO3-containing patches has further reduced their swelling ratio, which then significantly slowed down the release of Gemcitabine, to a point where 4-layered patches could release the drug over a period of 7 days in vitro. Remarkably, it was shown that 3-layered and 4-layered Gemcitabine loaded patches were successful in inhibiting pancreatic cancer cell growth for a period of 14 days when tested in vitro. Lastly, in vivo experiments showed that gemcitabine-loaded 4-layered patches were capable of reducing the tumor growth rate and caused no severe toxicity when tested in mice. Altogether, 3D printed hydrogel patches might be used as biocompatible implants for local delivery of drugs to diseased site, to either shrink the tumor or to prevent the tumor recurrence after resection.

Influence of Magnetic Scaffold Loading Patterns on their Hyperthermic Potential against Bone Tumors

Magnetic scaffolds have been investigated as promising tools for the interstitial hyperthermia treatment of bone cancers, to control local recurrence by enhancing radio- and chemotherapy effectiveness. The potential of magnetic scaffolds motivates the development of production strategies enabling tunability of the resulting magnetic properties. Within this framework, deposition and drop-casting of magnetic nanoparticles on suitable scaffolds offer advantages such as ease of production and high loading, although these approaches are often associated with a non-uniform final spatial distribution of nanoparticles in the biomaterial. The implications and the influences of nanoparticle distribution on the final therapeutic application have not yet been investigated thoroughly. In this work, poly-caprolactone scaffolds are magnetized by loading them with synthetic magnetic nanoparticles through a drop-casting deposition and tuned to obtain different distributions of magnetic nanoparticles in the biomaterial. The physicochemical properties of the magnetic scaffolds are analyzed. The microstructure and the morphological alterations due to the reworked drop-casting process are evaluated and correlated to static magnetic measurements. THz tomography is used as an innovative investigation technique to derive the spatial distribution of nanoparticles. Finally, multiphysics simulations are used to investigate the influence on the loading patterns on the interstitial bone tumor hyperthermia treatment.

Lipid-Based Drug Delivery Systems in Regenerative Medicine

The most important goal of regenerative medicine is to repair, restore, and regenerate tissues and organs that have been damaged as a result of an injury, congenital defect or disease, as well as reversing the aging process of the body by utilizing its natural healing potential. Regenerative medicine utilizes products of cell therapy, as well as biomedical or tissue engineering, and is a huge field for development. In regenerative medicine, stem cells and growth factor are mainly used; thus, innovative drug delivery technologies are being studied for improved delivery. Drug delivery systems offer the protection of therapeutic proteins and peptides against proteolytic degradation where controlled delivery is achievable. Similarly, the delivery systems in combination with stem cells offer improvement of cell survival, differentiation, and engraftment. The present review summarizes the significance of biomaterials in tissue engineering and the importance of colloidal drug delivery systems in providing cells with a local environment that enables them to proliferate and differentiate efficiently, resulting in successful tissue regeneration.