Search Results (452)

Surface engineering is a key strategy for modulating the biological behavior of TiO₂-based nanomaterials, with potential relevance for future localized or adjuvant approaches targeting residual cancer cells. This study evaluated whether amine functionalization and subsequent gold decoration modify the effects of TiO₂ nanoparticles (TiO₂NPs) on MCF7 and MDA-MB-231 breast cancer cells. The synthesized materials preserved the anatase TiO₂ framework, while surface modification altered their physicochemical and optical properties. After 24 h of exposure, pristine TiO₂NPs produced minimal changes in cell viability, whereas NH₂-functionalized TiO₂NPs (TiO₂NPs-NH₂) and gold-decorated NH₂-functionalized TiO₂NPs (Au@TiO₂NPs-NH₂) reduced viability in a concentration-dependent and cell line-dependent manner. These effects were more evident in the MTT assay than in Trypan Blue exclusion counting, suggesting changes in metabolic activity before extensive membrane integrity loss. Overall, the findings indicate that surface modification, rather than the TiO₂ core alone, is a major determinant of the cellular response to these nanomaterials. These results provide an initial in vitro basis for further mechanistic studies evaluating surface-engineered TiO₂NPs as candidate platforms for future adjuvant breast cancer strategies. Full article

Bone loss in the maxillofacial region arises from multiple causes, including periodontal disease, trauma, surgical procedures, infection, congenital anomalies, and cancer. Traditional treatment relies on bone grafting, either alone or in combination with biomaterials. Advances in tissue engineering have introduced synthetic or natural scaffolds to mimic the mineralized bone matrix. Natural scaffolds offer excellent biocompatibility and similarity to native tissue but often lack sufficient mechanical strength and exhibit poor degradation rates. Synthetic scaffolds provide tunable porosity and mechanical stability; however, their biological inertness makes them poor sources of osteogenic signaling. A key factor in the success of any scaffold is its interaction with the host immune system. Upon implantation, the innate immune response is initiated, with neutrophils and macrophages being the first cells to contact the scaffold. Macrophage polarization toward proinflammatory (M1) or anti-inflammatory (M2) phenotypes determines whether the microenvironment favors inflammation or remodeling. The adaptive immune response also plays a critical role: T and B lymphocytes may promote tolerance and integration through Th2/Treg pathways and antibody-mediated regulation, or they may trigger chronic inflammation and rejection through Th1/Th17 activation. This review examines the natural and synthetic materials used for bone remodeling and their biological properties. It then outlines the sequence of immune events occurring from the moment a scaffold is implanted to its potential integration or failure. Finally, this study highlights the relevance of cellular models and in vitro assays for the early evaluation of immunogenicity and biocompatibility, which are essential for optimizing scaffold design and improving outcomes in maxillofacial bone regeneration. Full article

Intraperitoneal (I.P.) delivery of cell-based therapeutics represents a promising strategy for treating regional peritoneal diseases; however, rapid cellular clearance severely limits therapeutic durability. A critical unmet need is the development of implantable biomaterial platforms that can both mechanically integrate within the dynamic I.P. cavity and sustain viable cell persistence in vivo. Here, we establish a Continuous Liquid Interface Production (CLIP)-based 3D bioprinting strategy to engineer transplantable, cell-laden hydrogel scaffolds optimized for I.P. implantation. Through systematic bioresin design, we identify a GelMA-PEGDA formulation that achieves a balance between high-resolution printability, tissue-matched mechanical characteristics (Young’s modulus 10–15 kPa), and controlled biodegradation (~75% mass loss over 14 days). The resulting constructs support sustained cell viability and proliferation for over 30 days in vitro. Importantly, in an animal study conducted in 6–8 weeks of female nude mice, in vivo I.P. implantation demonstrates a ~10-fold extension in cellular persistence compared to direct cell injection, prolonging the time to 50% signal decay from ~3 days to ~30 days, with detectable cell retention approaching two months in select animals. The platform further accommodates multiple clinically relevant cell types, including human mesenchymal stem cells and neural stem cells, highlighting its translational versatility. Collectively, this work defines key material and architectural parameters required for I.P. implantable cell therapeutics and establishes CLIP-based bioprinting as a scalable strategy for regional delivery of living therapeutics. Full article

The tumor microenvironment (TME) acts as a major barrier to effective drug delivery and contributes to drug resistance in solid tumors. Hypoxia, acidosis, and elevated interstitial fluid pressure limit drug penetration, while cancer-associated fibroblasts and immunosuppressive cells promote survival signaling, drug efflux, and metabolic adaptation. Polymeric drug delivery systems offer a promising strategy to address these barriers because their structures can be precisely engineered and designed to respond to TME-specific stimuli. These properties enable controlled drug release at tumor sites and help improve therapeutic efficacy while reducing systemic limitations. This review discusses how physicochemical and cellular components of the TME contribute to drug resistance and how polymeric nanomedicines can be designed to overcome these barriers. In addition, it examines key challenges that limit clinical translation, including tumor heterogeneity, variable enhanced permeability and retention effects, manufacturing scalability, and regulatory requirements. Finally, this review highlights the future direction of polymer nanomedicine and focuses specifically on developing rational material design, enhancing preclinical models, and developing clinically appropriate strategies to combat TME-mediated drug resistance. Full article

Since current therapies cannot regenerate lost myocardium or reverse adverse ventricular remodeling—major contributors to worldwide cardiovascular mortality—advanced biomaterials, particularly hydrogels, have emerged as promising therapeutic platforms. Among these, bacterial nanocellulose (BNC) has gained increasing attention due to its hydrated nanofibrillar architecture, high crystallinity, robust mechanical performance, and excellent water-retention capacity, features that closely resemble key aspects of the native extracellular matrix. These properties provide a favorable microenvironment for cell adhesion, survival, and tissue organization in cardiovascular applications. Preclinical evidence suggests that BNC-based cardiac constructs, including acellular patches and cell-laden systems, may reduce post-infarction ventricular dilation, promote angiogenesis, and improve cellular engraftment. In vascular tissue engineering, BNC has also been explored in small-diameter grafts, anisotropic hydrogel systems, and shape-memory conduits with encouraging hemocompatibility and functional durability. Functional modifications—including gelatin incorporation, oxidative surface treatments, peptide grafting, conductive polymers, and structural alignment strategies—further expand the biological and mechanical versatility of BNC-based systems. In addition, BNC-containing bioinks have demonstrated promising rheological behavior, printability, and cell compatibility for 3D bioprinting applications. Despite these advances, important challenges remain, including optimization of material functionalization, host integration, degradation control, vascularization, scalable manufacturing, and regulatory translation toward clinical application. Full article

The emerging threat of antibiotic-resistant pathogens and the limitations that conventional cancer chemotherapies display have created an urgent need for the development of innovative therapeutic strategies. Combining the pleiotropic biological roles of antimicrobial peptides (AMPs) and nanomaterials through their conjugation presents a promising possibility of targeting both microbial membranes and malignant cells. In the present study, we engineered a novel bioactive material by immobilizing the insect-derived AMP Papiliocin onto multi-walled—decorated with polyethylene–glycol—carbon nanotubes (PEG-MWCNTs) to prevent proteolytic degradation of the peptide and enhance its cellular delivery. Recombinant Papiliocin was cloned, heterologously expressed, purified and conjugated onto the PEG-MWCNT carrier. Successful expression and conjugation were validated via immunoblotting and Fourier transform infrared (FT-IR) spectroscopy, respectively. Further physicochemical characterization of the bionanocomposites was conducted using Dynamic Light Scattering (DLS) and Zeta potential measurements. Biologically, the biofunctionalized material exhibited potent, broad-spectrum antimicrobial activity both on Staphylococcus aureus and Escherichia coli, inhibiting almost 90% of the latter’s growth, highlighting the bioconjugate’s specific interactions with the Gram-negative pathogens’ membranes. Furthermore, it significantly reduced biofilm formation in Candida albicans, as indicated by the TCP assay. In parallel with its antimicrobial effects, CNTs-PEG–Papiliocin significantly reduced cancer cell viability and induced apoptosis via the extrinsic apoptosis pathway in HeLa cells, a response assisted by efficient intracellular delivery. Notably, cytotoxicity assays demonstrated lesser cytotoxic effect against non-tumorigenic HaCaT cells relative to the cancerous cell line. Collectively, these findings indicate the Papiliocin–biofunctionalized CNTs as a versatile, dual-action therapeutic agent with potential for antimicrobial activity and anticancer mode of action. Full article

Interbody fusion cages are widely used to restore spinal stability, yet conventional designs often exhibit mechanical mismatch and limited biological integration. Functionally graded spinal cages incorporate spatial variations in composition and structure to better align mechanical properties with the surrounding bone environment. Although these designs have been extensively studied from an engineering perspective, their biological implications remain less clearly defined. This review examines how graded material composition, surface characteristics, porosity, and lattice architecture are associated with cellular and molecular responses relevant to bone regeneration. Reported biological responses include protein adsorption, immune modulation, angiogenesis, and osteogenic differentiation. Evidence from orthopaedic implants and tissue engineering systems suggests that such design features may influence mechanobiological pathways; however, direct experimental validation in spinal applications remains limited. Previous reviews primarily focus on material properties or mechanical performance of functionally graded spinal cages. This review presents a structured design-to-biology perspective linking graded implant features with biological responses relevant to spinal fusion. By integrating findings across biomaterials, mechanobiology, and implant design, this review presents a structured design-to-biology perspective and highlights current evidence, translational limitations, and key knowledge gaps in the field. Functionally graded spinal cages represent a promising but still evolving strategy, and further spine-specific mechanobiological and clinical studies are required to establish their impact on fusion outcomes. Full article

Poor vascularization is one of the basic obstacles to the regeneration of functioning tissues because an oxygen diffusion process and elimination of wastes are essential in preserving the grafts. Recently, biomaterials have allowed the invention of bioinspired polymer scaffolds and replicated the natural extracellular matrix (ECM) due to the mechanical tunability of the synthetic polymers with the biological signals of natural macromolecules. The review uses a mechanistic analysis of the strategies to improve angiogenesis by using surface topography modification, bioactive peptide incorporation and pre-vascularization. Another way to achieve complex, perfusable topologies is by using more sophisticated methods of fabrication, such as electrospinning, 3D/4D bioprinting, or microfluidics. Based on in vitro and in vivo results, we determine angiogenic effectiveness by using cellular assays and animal transfers, pointing towards the translational advances in patents and clinical uses of bone, cardiac, nervous, and skin tissues. In spite of the substantial improvements, large-scale production and high demands of the regulations still exist. The future directions include the incorporation of bioinspired designs and intelligent materials, nanotechnology, and AI-based optimization into developing patient-specific and adaptive scaffolds. The following innovations herald the advent of highly effective constructs that can be used to regenerate tissue and overcome the limitations of present tissue engineering therapies through the introduction of highly effective, vascularized constructs. Full article

Hydrogel scaffolds have emerged as a central platform in tissue engineering due to their ability to mimic the extracellular matrix and support cellular functions. Among natural polymers, chitin and its derivative chitosan have emerged as valuable candidates for hydrogel scaffold development because of their biodegradability, compatibility with living tissues, and inherent biological functionality; however, their distinct and complementary roles in hydrogel scaffold design are often insufficiently differentiated in the literature. This review provides a comprehensive and mechanism-driven analysis of chitin- and chitosan-based hydrogel scaffolds, emphasising how their molecular structure governs network formation, mechanical performance, and biological functionality. Chitin is highlighted primarily as a structurally robust and crystalline component suitable for reinforcement. In contrast, chitosan serves as a versatile, soluble, and chemically reactive matrix enabling various crosslinking and functionalization strategies. Recent advances in physical, ionic, and covalent crosslinking as well as composite scaffold engineering, biofunctionalization, and emerging fabrication approaches such as injectable systems and three-dimensional bioprinting are systematically examined. The relationships between scaffold architecture, degradation behaviour, and cellular responses are discussed in key tissue engineering applications, including bone, cartilage, skin, and nerve regeneration. Importantly, this review introduces a unified structure–property–function framework that distinguishes the roles of chitin and chitosan within hydrogel systems and links crosslinking mechanisms to application-specific performance requirements, an aspect not comprehensively addressed in previous studies. Current challenges related to mechanical limitations, material variability, and clinical translation are critically evaluated, and future perspectives for the rational design of next-generation biomimetic hydrogel scaffolds are proposed. Full article

Decellularized extracellular matrix (dECM) scaffolds derived from xenogeneic tissues represent promising biomaterials for tissue engineering. In this study, dECM scaffolds were developed and characterized from four ovine tissues—skin, tunica vaginalis, fascia lata, and pericardium—using a detergent-based decellularization protocol to evaluate decellularization efficiency and extracellular matrix (ECM) preservation. Decellularization was performed using a sequential detergent-based protocol with sodium dodecyl sulfate and Triton X-100. Decellularization efficacy and matrix preservation were evaluated through gross examination, histological analysis, scanning electron microscopy (SEM), and residual DNA quantification. Gross inspection revealed increased translucency and reduced pigmentation in decellularized tissues compared with native counterparts, indicating effective cellular removal while maintaining overall tissue architecture. Histological assessment confirmed the complete absence of nuclear and cytoplasmic material, alongside preservation of collagen-rich extracellular matrix organization. SEM analysis demonstrated well-maintained ultrastructural features, including aligned collagen fibers and porous ECM architecture, with complete removal of epithelial and stromal cellular elements. Quantitative analysis revealed approximately 94% reduction in residual DNA content across all decellularized tissues compared with native controls. This study demonstrated that the employed detergent-based protocol reliably produces structurally preserved, acellular scaffolds from multiple ovine tissues. The resulting biomaterials exhibit structural characteristics that support their potential use in tissue engineering applications, pending further functional validation. Full article

Bone tissue plays a vital role in the human body and possesses intrinsic self-repair mechanisms; however, large defects or pathological fractures may exceed its natural healing capacity. Bone tissue engineering provides promising strategies to restore bone integrity through the use of scaffolds, growth factors, and stem cells. While calcium phosphate (CaP)-based ceramics, such as hydroxyapatite (HAp) and tricalcium phosphate (TCP), represent the current benchmark, their limitations, including slow degradation (HAp) and limited osteoinductivity (TCP), have driven the development of alternative biomaterials. In this context, magnesium phosphate (MgP)-based materials have gained increasing attention due to their tunable resorption rate, improved biodegradability, and ability to stimulate osteogenesis and angiogenesis through the release of magnesium (Mg²⁺) ions. This study reports on composite scaffolds based on electrospun poly(ε-caprolactone) (PCL) fibres coated with MgP layers doped with lithium (Li) and zinc (Zn), designed to mimic the nanofibrous architecture of the extracellular matrix. Lithium and zinc were selected due to their known ability to modulate cellular response, with lithium promoting osteogenic activity and zinc contributing to improved cell proliferation and antibacterial potential. The phosphate phases obtained by coprecipitation were deposited onto the PCL fibres using Matrix-Assisted Pulsed Laser Evaporation (MAPLE), enabling controlled surface functionalization. Following thermal treatment, the formation of the crystalline magnesium pyrophosphate (Mg₂P₂O₇) phase was confirmed by chemical and structural characterization. The combination of a slowly degrading PCL matrix, providing sustained structural support, and a bioactive MgP coating, enabling rapid and controlled ion release, results in improved scaffold performance in terms of biocompatibility, biodegradability, and bioactivity. While the slow degradation rate of PCL ensures mechanical stability over an extended period, the surface-deposited MgP phase allows immediate interaction with the biological environment, facilitating faster ion release and enhancing cell–material interactions. These findings highlight the potential of the developed composites as promising candidates for trabecular bone regeneration and as viable alternatives to conventional CaP-based scaffolds in regenerative medicine. Full article

Introduction: Three-dimensional (3D) bioprinting is a promising approach for endodontic tissue engineering, enabling scaffolds with controlled architecture and bioactivity to support pulp regeneration. Objectives: This systematic review assessed the following: “What 3D bioprinting applications are reported in endodontics-related studies?” Materials and Methods: Following PRISMA 2020 guidelines, PubMed/MEDLINE, Scopus, Embase, Cochrane Library, Web of Science, SciELO, LILACS, and Google Scholar were searched up to January 2026 with no date or language limits. Two reviewers independently screened studies; risk of bias in in vitro studies was assessed with the QUIN tool. As only one study reported complete antimicrobial outcomes, an intra-study quantitative comparison (MD, 95% CI) of inhibition halos was performed (not a meta-analysis). Results: From 518 records, nine studies were included. Outcomes mainly addressed physicochemical properties (n = 9), cell viability (n = 7), biocompatibility (n = 5), and cell differentiation (n = 5); antimicrobial activity was evaluated in two studies. Most used hDPSCs and extrusion-based printing, testing calcium silicate composites, alginate hydrogels, functionalized PCL, and modified PLA. Modified PLA scaffolds showed greater antimicrobial activity, strongest with naringin and nHA formulations. Overall risk of bias was moderate (58.33%), largely due to limited reporting of randomization, blinding, and sampling. Conclusion: 3D-bioprinted scaffolds/bioinks generally improved cellular responses and bioactivity, especially with MTA, Biodentine, nHA, or naringin; antimicrobial effects were most evident in functionalized PLA (PLA/NAR and PLA/nHA/NAR). Full article

Tissue engineering integrates concepts from medicine, biology, and engineering to create living constructs capable of repairing, replacing, or supporting damaged tissues. This multidisciplinary field relies on the interplay between biomaterials, cellular sources, and bioactive signaling to achieve functional tissue regeneration. This review provides a comprehensive overview of recent advances in scaffold design, highlighting natural, synthetic, and hybrid materials, as well as innovative fabrication techniques such as electrospinning, 3D bioprinting, and smart biomaterials. It discusses the role of stem cells and growth factors in directing regeneration and examines a wide range of clinical applications, including skin regeneration, cartilage repair, bone tissue engineering, dental and periodontal regeneration, nerve repair, cardiac tissue engineering, liver tissue models, and ophthalmic applications. Current challenges, such as immune responses, limited vascularization, scalability, and regulatory barriers, are addressed alongside emerging strategies aimed at improving clinical translation. By integrating diverse tissue types and engineering approaches within a unified framework, this review offers a broad yet detailed perspective on the current state and future directions of regenerative medicine. Full article

Three-dimensional printed polymers produced using Fused Deposition Modelling (FDM) exhibit directional microstructures resulting from filament paths, layer interfaces, and cellular infill, leading to mechanical and tribological responses distinct from those of homogeneous bulk materials. This study presents a comparative tribomechanical evaluation of polypropylene (PP) bulk inserts and 3D-printed polyethylene terephthalate glycol (PETG) inserts with a 30% hexagonal infill, relevant for robotic gripping applications. Progressive scratch tests were performed under loads from 5 to 100 N (150 N for PP), and profilometry was applied to quantify groove morphology, ridge formation, and displaced-volume ratios. An elasto-plastic conical indentation model was used to derive indentation pressures and elastic–plastic transition radii from groove geometry. The PETG inserts exhibited heterogeneous groove depth, intermittent ridge tearing, and friction fluctuations associated with the internal infill structure, consistent with previous findings on anisotropy and architecture-dependent behaviour in additively manufactured polymers. In contrast, bulk PP demonstrated smoother friction profiles and more stable plastic flow under increasing loads. Two functional indices—specific frictional work and ridge-to-trace volumetric ratio—are introduced to support material selection for robotic gripping systems. The results show that local contact mechanics in 3D-printed inserts are governed by print-induced structural features and can be effectively evaluated through a scratch-based elasto-plastic analysis. The methods and results presented in this work support the rational selection and design of polymer inserts for robotic gripper fingertips. The proposed scratch-based elasto-plastic evaluation framework enables manufacturers and automation engineers to compare 3D-printed and conventional materials based on friction stability, wear response, and deformation resistance. This approach can be directly applied to optimise gripping performance in industrial handling, packaging, and collaborative robotics. Full article

Laser-directed energy deposition (DED) using wire or powder feedstock is a promising way to fabricate prototypes in rapid time, including complex metal parts for advanced engineering applications. In this work, AISI 316L stainless steel—a well-known, weldable alloy model—was used to perform a foundational comparative study of wire-fed (LW-DED) and powder-fed (LP-DED) processes, establishing a baseline before progressing to high-temperature alloys. Hollow cylindrical specimens were fabricated and characterized microstructurally and mechanically. LP-DED produced a refined cellular–dendritic structure with primary dendrite arm spacing of 3.29 ± 0.49 µm and slightly higher average hardness (226 ± 8 HV0.2), accompanied by fine, spherical porosity inherent to the powder feedstock. LW-DED generated coarser epitaxial columnar dendrites (5.15 ± 0.69 µm) and slightly lower hardness (206 ± 10 HV0.2) but achieved nearly full density and high material catching efficiency. The results indicate that both methods yield comparable deposits when parameters are controlled, with LP-DED offering enhanced microstructural refinement and LW-DED providing faster deposition and higher build volume. These findings provide practical guidance for the additive manufacturing of high-performance parts and establish a baseline for the application of DED processes to advanced alloys. Full article