Bone Tissue Engineering Research Articles

Advances in bone tissue engineering and dental regenerative medicine have made strides in the development of several biomaterials. Optimizing the chemical and physical milieu of scaffold is required to induce osteogenesis for faster bone regeneration. In this study, polymer blend of Polyvinyl Alcohol (PVA) and Polyvinylpyrrolidone (PVP) doped with nHAP-ZnO Np was prepared by a solution casting technique. Structural and physiochemical characterization was performed. In vitro cytotoxicity analysis was performed through tetrazolium-based assay (MTT) assay and the differentiated cells were subjected to alkaline phosphatase assay (ALP) and alizarin red S (ARS) analysis respectively. Scanning Electron microscopic (SEM) analysis showed a rough and uniform matrix arrangement of the PVA-PVP blend. Crystallites properties and functional groups was confirmed by X ray diffractometer (XRD) analysis and Fourier transform infrared spectroscopy (FT-IR) respectively. The optimal water absorption capacity was observed in PVA-PVP-nHAP-ZnO Np scaffold (P3) and also degradation pattern was analysed for PVA-PVP (P1), PVA-PVP-nHAP (P2) and PVA-PVP-nHAP-ZnO Np (P3) scaffolds where P3 scaffold holds high stability compared to P1 and P2 scaffolds. In the thermal stability analysis, PVA-PVP (P1) and PVA-PVP-nHAP-ZnO Np (P3) scaffolds showed an overall stability up to 270 °C. Highly miscible blends of PVA-PVP and 1 wt% nHAP - ZnO Np was observed with semi-crystallinity in Differential Scanning Calorimetry (DSC) analysis. The mechanical property of the PVA-PVP-nHAP-ZnO Np (P3) scaffold has shown an increasing trend in tensile strength analysis. The cytotoxic study of scaffolds showed 84% of cell viability confirming high biocompatibility than compared to plain scaffold. the elevated level of ALP and calcium deposition was observed in loaded scaffold (P3). Thus, PVA-PVP-nHAP-ZnO Np (P3) scaffold supports and induces osteogenesis and can be used as biomaterial in bone regenerative medicine.

Stem cell adhesion and migration are fundamental processes in tissue regeneration and repair; however, their efficiency in vivo is often limited by the complexity of the microenvironment. Endogenous bioelectrical cues, such as electric fields present during development and wound healing, play a critical role in guiding these cellular behaviors. Piezoelectric biomaterials, which can convert mechanical stimuli into electrical signals, have recently emerged as promising platforms for recapitulating these bioelectric cues without the need for external power sources. In this mini-review, we summarize the recent advances in the use of piezoelectric scaffolds to modulate stem cell adhesion and migration. We highlight the underlying mechanisms, including integrin/focal adhesion kinase activation, calcium signaling, and electrotaxis, which mediate enhanced adhesion, focal adhesion maturation, and directed cell migration. Representative applications in bone, cartilage, nerve, and muscle tissue engineering are discussed, with an emphasis on how piezoelectric scaffolds improve regeneration by providing dynamic and self-sustained electrical stimulation. Finally, we outline the major challenges, such as balancing piezoelectric output with biocompatibility, controlling in vivo stimulation parameters, and elucidating precise sensing mechanisms, and propose future directions for clinical translation. By integrating insights from materials science, mechanobiology, and regenerative medicine, piezoelectric biomaterials hold strong potential as next-generation smart scaffolds for orchestrating stem cell behavior and accelerating functional tissue repair.

Today, the engineering of load-bearing bone tissue after severe trauma still relies on metal-based (Ti, CoCrMo alloys or stainless steel) permanent implants. Such artificial scaffolds are typically applied in the body and come into direct contact with the recipient’s cells, whose adhesion affects the patient’s implant acceptance or rejection. The present study aims to create a nano-rough texture by means of ultra-short femtosecond laser (fs)-induced periodicity in the form of laser induced periodic surface structures (LIPSS) on the surface of a stainless steel implant model, which is additionally functionalized via magnetron-sputtering with a thin Cu layer, thus providing the as-created implants with a stable antimicrobial interface. Calcium phosphate (CaP) crystal growth was additionally applied due to the strong bioactive interface bond that CaPs provide to the bone connective tissue, as well as for the strong interface bond they create between the artificial implant and the surrounding bone tissue, thereby stabilizing the implanted structure within the body. The bioactive properties in the as-created antimicrobial hybrid topographical design, achieved through femtosecond laser-induced nanoscale surface structuring and micro-sized CaP crystal growth, have the potential for subsequent practical applications in bone tissue engineering.

Bioceramic incorporated polymer-based scaffolds have gained more interest as a promising effective approach in bone tissue engineering (BTE) applications. This study is the first to investigate the role of incorporated manganese-doped hydroxyapatite (Mn-HA) and gelatin coating in increased bioactivity and biological properties, specifically cell attachment potencies of 3D porous electrospun polycaprolactone (PCL). In this context, the novel 3D porous composite scaffolds were synthesized by wet-electrospinning of PCL incorporated with Mn-HA. The scaffolds were then coated with a thin gelatin layer to enhance the cell adhesin capacity. The effects of Mn-HA and the gelatin coating were evaluated in terms of structural, physicochemical, and biological properties. Results have demonstrated that Mn-HA was synthesized with successfully doping of 2mol% Mn, with MnSO4 and MnCl2 precursors. Mn-HA powder with MnSO4 precursor indicated better cell viability results. Therefore, Mn-HA/PCL scaffolds having 2.5 and 5% (w/w) bioceramic content were prepared with MnSO4 precursor. The scaffolds' porosity increased from 24% (PCL/gelatin group), to approximately 34% in both 2.5 and 5% (w/w) bioceramic containing groups. The addition of Mn-HA powder improved the in vitro bioactivity and degradation rate of the scaffolds. Specifically, 5% and 2.5% (w/w) Mn-HA incorporated scaffolds indicated 40% and 30% weight loss after 21 days of incubation, respectively. In contrast to PCL/gelatin and HA containing groups, the Mn-doped HA containing scaffolds exhibited a weight loss around 17-20%, indicating a decrease in degradation. The presence of Mn-HA powder and gelatin coat elevated the cell viability results significantly, as opposed to PCL scaffolds. Incorporation of 5% (w/w) Mn-HA improved the ALP activity and intracellular calcium levels, contrary to other groups. Thus, the incorporation of Mn-doped HA and gelatin into the PCL scaffold supported the potency towards properties required for BTE applications and suggested it as a prospective biomaterial for further evaluations.

Firstly apatite-type carbonated calcium phosphate and biphasic calcium phosphates (mixture of phases based on Ca10(PO4)6(OH)2 and β-Ca3(PO4)2 with weight ratio 60 : 40%) which contained the trace elements complex (Na+, Mg2+, Zn2+) were obtained from aqueous solutions and heated to 600 °C. Composites based on apatite-related calcium phosphates with 5, 10, 25wt% of ZrO2 were also prepared used one-stage method. In vitro testing of new prepared samples in phosphate-buffered solution (at 37 °C and pH = 7.45) showed increasing of pH value to 10 during 96 h in the presence of apatite-related Na+ (0.6wt%), Mg2+ (0.6wt%), Zn2+ (1.7wt%), CO32- (3wt%)-containing calcium phosphate. At the same time, increasing of pH only to 8.78 during 48 h was found for the biphasic calcium phosphate with the similar amount of doping cations. This result indicates that carbonated modified hydroxyapatites can be more appropriate for bone tissue engineering than biphasic calcium phosphates with similar amount of trace elements. An increase in the ZrO2 amount from 10 to 25 wt% in the composite with apatite-related Na+ (0.6wt%), Mg2+ (0.6wt%), Zn2+ (1.7wt%), CO32- (3wt%)-containing calcium phosphate led to an increase of its hardness in 1.4 times. The results of in vitro investigation using both the MTT and resazurin assays demonstrate that the prepared apatite-related Na+ (0.6wt%), Mg2+ (0.6wt%), Zn2+ (1.7wt%), CO32-(3wt%)-containing calcium phosphate and its composite with 25 wt% ZrO2 have a dose-dependent effect on the metabolic and proliferation activity (viability) of the mouse monocyte-macrophage RAW264.7 and J774A.1 cell lines. The stimulation of RAW264.7 macrophages growth within 100–155% compared with the control was found at samples concentration 0.1 and 0.01 mg/ml in the cell cultivation medium. Obtained results are important at creation of bioactive materials with special microhardness for the medical application.

Progress in Carbon Nanotube-Assisted Osteogenic Differentiation of Mesenchymal Stem Cells and Its Application in Bone Tissue Engineering

Potential of organ‑on‑a‑chip in advancing synthetic extracellular matrix technology for bone tissue engineering in dentistry (Review)

Since the discovery of 3D-printing, it has revolutionized personalized drug delivery and implants by enabling intricate, customizable designs. However, key challenges remain, including complex design, host immune response, biofilm formation, and infection-induced inflammation at the implant site. This work offers, first-ever, unique ginger-based 3D-printable resins by chemically modifyingZingerol (Zing-OH, a ginger-based component) into photopolymerizable compositions that can print high-resolution complex designs via DLP 3D-printing. Briefly, the Zing-OH is amended via different functional group backbones, resulting in Zing-OH-based resins (ether, ester, and urethane) and their respective prints. Moreover, the Zing-OH prints' thermal, mechanical, and biodegradation properties can be fine-tuned by simply customizing the backbone. Furthermore, the shape memory efficacy and the human bone (nasal cartilage, vestibular, cortical, femur, etc.) mimicking mechanical properties (exhibiting 2-200 MPa compressive strength) makes them more enticing. In tandem, the prints are also hemocompatible as well as cyto-friendly against human skin (HaCaT) and lung (BEAS-2B) cells, and mouse fibroblast (NIH-3T3) cells. Concurrently, an in vivo biocompatibility study in a rat model indicates that the printed materials are biocompatible, showing no signs of severe inflammatory response over a 28-day period. More importantly, the outstanding anti-biofilm and antioxidant efficacies of the Zing-OH prints make them more appealing due to their potential to prevent implant rejection, thus making them promising tools for bone-tissue engineering (BTE) applications.

Progranulin-loaded silk fibroin/chitosan scaffold with polydopamine modification promotes bone regeneration via PI3K/Akt pathway activation.

3D printing of an anatomically shaped bone model inspired by vascularized tubular bone structure.

The promising outcome of Bone Tissue Engineering (BTE) via scaffolds for treating segmental bone defects (SBDs) has led the interdisciplinary field of Materials Science to take a new turn and explore innovative biomaterials that enhance tissue regeneration. The most recent advancement is the application of electrical stimulation with the use of conductive and piezoelectric biomaterials to develop conductive and electroactive (EA) scaffolds that activate osteoblast formation, leading to a significantly faster and more robust bone healing process. Researchers have explored plenty of biomaterials and scaffold fabrication techniques. This article presents a comprehensive review of the popular biomaterials that include Conductive Polymers (PANI, Poly-pyrrole, PEDOT), Piezoelectric Polymers (PVDF, TrFE, PLLA, PAs), Metallic Nanoparticles (NPs) (Ag, TiO2), and Carbon-based NPs (CNTs, Graphene, Graphene Oxide) used for the development of conductive and EA biocompatible scaffolds. Various innovative conductive and electroactive scaffold fabricating methods, like 3D printing, bio-printing, electrospinning, etc., that precisely command over the conductive filler distribution, porosity, and pore size interconnectivity are highlighted. Tests explored by researchers for investigating the conductive and piezoelectric properties of the developed scaffolds and their osteogenic potential (in vitro and invivo) are also presented. Apart from this, standard protocols for the conduction of these tests, regulatory pathways, scope for clinical translations, and their respective challenges have been reviewed. Most importantly, the review not only focuses on the material versatility and fabrication techniques but also critically analyzes the challenges involved in optimizing the biomaterials and fabrication parameters to develop bone scaffolds with the best-optimized physicochemical, mechanical, biological, and conductive properties.

Fabrication, physicochemical characterization and in vitro evaluation of pre-osteoblast cells on bacterial cellulose/hydroxyapatite reinforced with chitosan composite scaffold for bone tissue engineering.

In this study, calcium aminopolycarboxylate-based coordination polymers, calcium acetamidoiminodiacetate (CaADA) and tetraaqua(ethylenediaminetetraacetato)-calcium (II) strontium (II) monohydrate (SrCaEDTA) were incorporated into polyacrylamide-sodium alginate hydrogel scaffolds, aiming to improve calcium absorption in MG-63 cells. Cytotoxicity of the coordination polymers in MG-63 osteoblast-like cells was studied by MTT assay. The mechanical performance and degradation behaviour of the scaffolds were systematically investigated. Porosity measurements were done via SEM analysis, and calcium ion release profile was evaluated by inductively coupled plasma mass spectrometry (ICP-MS) measurements. The calcium deposition studies revealed that the integration of the coordination polymers enhanced the calcium absorption in MG-63 cells. The coordination polymer-incorporated hydrogel scaffolds can be developed as future materials for bone tissue engineering and bone repair applications.

Whitlockite as a next-generation biomaterial for bone regeneration: A systematic review of In Vivo evidence for bone regeneration.

Fabrication and Characterization of Electrospun Sr/Zn-Doped Nano-Hydroxyapatite-Collagen-PLGA Nanofibrous Scaffolds for Bone Tissue Engineering

Harmonizing dual electrospun/sponge structures within a triad gellan gum/eucalyptus/Cu-doped baghdadite composition for bone tissue engineering

Background: Three-dimensional (3D) printed scaffolds have emerged as promising tools for bone regeneration, but the optimal structural design and pore size remain unclear. Polylactic acid (PLA) reinforced with graphene oxide (GO) offers enhanced mechanical and biological performance, yet systematic evaluation of architecture and pore size is limited. Methods: Two scaffold architectures (lattice-type and dode-type) with multiple pore sizes were fabricated using UV-curable PLA/GO resin. Physical accuracy, porosity, and mechanical properties were assessed through compression and fatigue testing. Based on in vitro screening, four pore sizes (930 μm, 690 μm, 558 μm, 562 μm) within the dode-type structure were analyzed. The 558 μm and 562 μm scaffolds, showing distinct fracture thresholds, were further evaluated in rat and rabbit calvarial defect models for inflammation and bone regeneration. Results: In vitro testing revealed that while 930 μm and 690 μm scaffolds exhibited superior compressive strength, the 562 μm scaffold showed a unique critical fracture behavior, and the 558 μm scaffold offered comparable stability with higher resistance to premature failure. In vivo studies confirmed excellent biocompatibility in both groups, with early bone formation favored in the 558 μm scaffold and more continuous and mature bone observed in the 562 μm scaffold at later stages. Conclusions: This stepwise strategy—from structural design to pore size screening and preclinical validation—demonstrates that threshold-level mechanical properties can influence osteogenesis. PLA/GO scaffolds optimized at 558 μm and 562 μm provide a translationally relevant balance between mechanical stability and biological performance for bone tissue engineering.

The development of bone tissue engineering scaffolds that combine biomimetic architecture with osteoinductive properties remains a challenge. In this study, a series of poly(lactic acid)/calcium polyphosphate/graphene oxide (PLA/CPP/GO) composite scaffolds with varying GO contents were fabricated via phase separation. The influence of GO concentration on the scaffold properties was systematically investigated. Results indicated that the incorporation of GO markedly enhanced the microstructure, hydrophilicity, and bioactivity of the scaffolds. Specifically, at GO loadings of 0.5–1.5 wt%, the scaffolds developed a refined fibrous architecture with highly interconnected pores (porosity > 90%), and demonstrated optimal mechanical strength (compressive strength ∼2.34 MPa) and improved wettability. More significantly, GO effectively augmented the biomineralization capacity and osteogenic potential of the scaffolds. In vitro biomineralization assays revealed that GO facilitated the deposition of carbonate hydroxyapatite. Cell culture studies further showed that scaffolds with 0.5 wt% GO significantly enhanced alkaline phosphatase (ALP) activity in MC3T3-E1 cells, indicating promoted osteogenic differentiation. This study demonstrates that an appropriate amount of GO can endow PLA/CPP-based scaffolds with favorable mechanical properties, high porosity, excellent bioactivity, and osteoinductivity, making them promising candidates for bone tissue engineering applications.

Near-infrared responsive nanozyme-carboxymethyl chitosan/chondroitin sulfate composite hydrogel: Multicomponent synergy optimizes bone defect microenvironment to enhance repair.

Three-dimensional (3D)-printed poly-ε-caprolactone (PCL) scaffolds lack sufficient bioactivity for optimal bone tissue engineering applications. This shortcoming can be overcome by coating PCL scaffolds with collagen and hydroxyapatite (PCL/col-HA) or by applying a collagen coating to PCL-HA composite scaffolds (PCL-HA/col). Here we aimed to test which type of scaffold is more effective in stimulating osteogenic activity. Moreover, the scaffolds' physicomechanical properties were characterized. 3D-printed PCL/col-HA containing 10, 20, or 30% HA particles, and 3D-printed PCL-HA/col containing 10, 20, or 30% HA particles with collagen coating were fabricated. MC3T3-E1 pre-osteoblasts were cultured on the scaffolds for 14 days. The physicomechanical properties of the scaffolds and pre-osteoblast functionality were evaluated through experiments and finite element (FE) modeling. We found that coating of PCL scaffolds with collagen and HA or coating of PCL-HA composite scaffolds with collagen changed the geometry and topography of the scaffold surfaces. Furthermore, PCL/col-HA and PCL-HA/col showed higher surface roughness and elastic modulus, but lower water contact angle, than PCL scaffolds. FE-modeling showed that all scaffolds tolerated up to 2% compressive strain, which was lower than their yield stress. 3D-printed PCL/col-HA and PCL-HA/col scaffolds promoted pre-osteoblast proliferation and osteogenic activity compared to unmodified PCL scaffolds. PCL-HA/col scaffolds increased pre-osteoblast proliferation and collagen deposition, whereas PCL/col-HA scaffolds increased alkaline phosphatase activity and calcium deposition. Osteogenic activity of pre-osteoblasts was more enhanced on 3D-printed PCL/col-HA scaffolds than on PCL-HA/col scaffolds, particularly in the short-term, which seems promising for in vivo bone tissue engineering.