Propelling Minimally Invasive Tissue Regeneration With Next-Era Injectable Pre-Formed Scaffolds

The growing aging population, with its associated chronic diseases, underscores the urgency for effective tissue regeneration strategies. Biomaterials play a pivotal role in the realm of tissue reconstruction and regeneration, with a distinct shift toward minimally invasive (MI) treatments. This transition, fueled by engineered biomaterials, steers away from invasive surgical procedures to embrace approaches offering reduced trauma, accelerated recovery, and cost-effectiveness. In the realm of MI tissue repair and cargo delivery, various techniques are explored. While in situ polymerization is prominent, it is not without its challenges. This narrative review explores diverse biomaterials, fabrication methods, and biofunctionalization for injectable pre-formed scaffolds, focusing on their unique advantages. The injectable pre-formed scaffolds, exhibiting compressibility, controlled injection, and maintained mechanical integrity, emerge as promising alternative solutions to in situ polymerization challenges. The conclusion of this review emphasizes the importance of interdisciplinary design facilitated by synergizing fields of materials science, advanced 3D biomanufacturing, mechanobiological studies, and innovative approaches for effective MI tissue regeneration.

Hydrogel-Based Growth Factor Delivery Platforms: Strategies and Recent Advances

Growth factors play a crucial role in regulating a broad variety of biological processes and are regarded as powerful therapeutic agents in tissue engineering and regenerative medicine in the past decades. However, their application is limited by their short half-lives and potential side effects in physiological environments. Hydrogels are identified as having the promising potential to prolong the half-lives of growth factors and mitigate their adverse effects by restricting them within the matrix to reduce their rapid proteolysis, burst release, and unwanted diffusion. This review discusses recent progress in the development of growth factor-containing hydrogels for various biomedical applications, including wound healing, brain tissue repair, cartilage and bone regeneration, and spinal cord injury repair. In addition, the review introduces strategies for optimizing growth factor release including affinity-based delivery, carrier-assisted delivery, stimuli-responsive delivery, spatial structure-based delivery, and cellular system-based delivery. Finally, the review presents current limitations and future research directions for growth factor-delivering hydrogels.

Bone Organoids: Recent Advances and Future Challenges

Bone defects stemming from tumorous growths, traumatic events, and diverse conditions present a profound conundrum in clinical practice and research. While bone has the inherent ability to regenerate, substantial bone anomalies require bone regeneration techniques. Bone organoids represent a new concept in this field, involving the 3D self-assembly of bone-associated stem cells guided in vitro with or without extracellular matrix material, resulting in a tissue that mimics the structural, functional, and genetic properties of native bone tissue. Within the scientific panorama, bone organoids ascend to an esteemed status, securing significant experimental endorsement. Through a synthesis of current literature and pioneering studies, this review offers a comprehensive survey of the bone organoid paradigm, delves into the quintessential architecture and ontogeny of bone, and highlights the latest progress in bone organoid fabrication. Further, existing challenges and prospective directions for future research are identified, advocating for interdisciplinary collaboration to fully harness the potential of this burgeoning domain. Conclusively, as bone organoid technology continues to mature, its implications for both clinical and research landscapes are poised to be profound.

Emerging advances in hydrogel-based therapeutic strategies for tissue regeneration

Significant developments in cell therapy and biomaterial science have broadened the therapeutic landscape of tissue regeneration. Tissue damage is a complex biological process in which different types of cells play a specific role in repairing damaged tissues and growth factors strictly regulate the activity of these cells. Hydrogels have become promising biomaterials for tissue regeneration if appropriate materials are selected and the hydrogel properties are well-regulated. Importantly, they can be used as carriers for living cells and growth factors due to the high water-holding capacity, high permeability, and good biocompatibility of hydrogels. Cell-loaded hydrogels can play an essential role in treating damaged tissues and open new avenues for cell therapy. There is ample evidence substantiating the ability of hydrogels to facilitate the delivery of cells (stem cell, macrophage, chondrocyte, and osteoblast) and growth factors (bone morphogenetic protein, transforming growth factor, vascular endothelial growth factor and fibroblast growth factor). This paper reviewed the latest advances in hydrogels loaded with cells or growth factors to promote the reconstruction of tissues. Furthermore, we discussed the shortcomings of the application of hydrogels in tissue engineering to promote their further development.

A 3D-Printed Assemblable Bespoke Scaffold as a Versatile Microcryogel Carrier for Site-Specific Regenerative Medicine

Advances in additive manufacturing have led to diverse patient-specific implant designs utilizing computed tomography, but this requires intensive work and financial implications. Here, Digital Light Processing is used to fabricate a hive-structured assemblable bespoke scaffold (HIVE). HIVE can be manually assembled in any shape/size with ease, so a surgeon can create a scaffold that will best fit a defect before implantation. Simultaneously, it can have site-specific treatments by working as a carrier filled with microcryogels (MC) incorporating different biological factors in different pockets of HIVE. After characterization, possible site-specific applications are investigated by utilizing HIVE as a versatile carrier with incorporated treatments such as growth factors (GF), bioceramic, or cells. HIVE as a GF-carrier shows a controlled release of bone morphogenetic protein/vascular endothelial growth factor (BMP/VEGF) and induced osteogenesis/angiogenesis from human mesenchymal stem cells (hMSC)/human umbilical vein endothelial cells (HUVECs). Furthermore, as a bioceramic-carrier, HIVE demonstrates enhanced mineralization and osteogenesis, and as a HUVEC carrier, it upregulates both osteogenic and angiogenic gene expression of hMSCs. HIVE with different combinations of MCs yields a distinct local effect and successful cell migration is confirmed within assembled HIVEs. Finally, an in vivo rat subcutaneous implantation demonstrates site-specific osteogenesis and angiogenesis.

3D-printed LEGO®-inspired titanium scaffolds for patient-specific regenerative medicine

Despite the recent advances in 3D-printing, it is often difficult to fabricate implants that optimally fit a defect size or shape. There are some approaches to resolve this issue, such as patient-specific implant/scaffold designs based on CT images of the patients, however, this process is labor-intensive and costly. Especially in developing countries, affordable treatment options are required, while still not excluding these patient groups from potential material and manufacturing advances. Here, a selective laser melting (SLM) 3D-printing strategy was used to fabricate a hierarchical, LEGO®-inspired Assemblable Titanium Scaffold (ATS) system, which can be manually assembled in any shape or size with ease. A surgeon can quickly create a scaffold that would fit to the defect right before the implantation during the surgery. Additionally, the direct inclusion of micro- and macroporous structures via 3D-printing, as well as a double acid-etched surface treatment (ST) in the ATS, ensure biocompatibility, sufficient nutrient flow, cell migration and enhanced osteogenesis. Three different structures were designed (non-porous:NP, semi-porous:SP, ultra-porous:UP), 3D-printed with the SLM technique and then surface treated for the ST groups. After analyzing characteristics of the ATS such as printing quality, surface roughness and interconnected porosity, mechanical testing and finite element analysis (FEA) demonstrated that individual and stacked ATS have sufficient mechanical properties to withstand loading in a physiological system. All ATS showed high cell viability, and the SP and UP groups demonstrated enhanced cell proliferation rates compared to the NP group. Furthermore, we also verified that cells were well-attached and spread on the porous structures and successful cell migration between the ATS units was seen in the case of assemblies. The UP and SP groups exhibited higher calcium deposition and RT-qPCR proved higher osteogenic gene expression compared to NP group. Finally, we demonstrate a number of possible medical applications that reveal the potential of the ATS through assembly.

Polysaccharide-bioceramic composites for bone tissue engineering: A review

Limitations associated with conventional bone substitutes such as autografts, increasing demand for bone grafts, and growing elderly population worldwide necessitate development of unique materials as bone graft substitutes. Bone tissue engineering (BTE) would ensure therapy advancement, efficiency, and cost-effective treatment modalities of bone defects. One way of engineering bone tissue scaffolds by mimicking natural bone tissue composed of organic and inorganic phases is to utilize polysaccharide-bioceramic hybrid composites. Polysaccharides are abundant in nature, and present in human body. Biominerals, like hydroxyapatite are present in natural bone and some of them possess osteoconductive and osteoinductive properties. Ion doped bioceramics could substitute protein-based biosignal molecules to achieve osteogenesis, vasculogenesis, angiogenesis, and stress shielding. This review is a systemic summary on properties, advantages, and limitations of polysaccharide-bioceramic/ion doped bioceramic composites along with their recent advancements in BTE.

Advances and Prospects in Materials for Craniofacial Bone Reconstruction

The craniofacial region is composed of 23 bones, which provide crucial function in keeping the normal position of brain and eyeballs, aesthetics of the craniofacial complex, facial movements, and visual function. Given the complex geometry and architecture, craniofacial bone defects not only affect the normal craniofacial structure but also may result in severe craniofacial dysfunction. Therefore, the exploration of rapid, precise, and effective reconstruction of craniofacial bone defects is urgent. Recently, developments in advanced bone tissue engineering bring new hope for the ideal reconstruction of the craniofacial bone defects. This report, presenting a first-time comprehensive review of recent advances of biomaterials in craniofacial bone tissue engineering, overviews the modification of traditional biomaterials and development of advanced biomaterials applying to craniofacial reconstruction. Challenges and perspectives of biomaterial development in craniofacial fields are discussed in the end.

Advancements and Applications of Injectable Hydrogel Composites in Biomedical Research and Therapy

Injectable hydrogels have gained popularity for their controlled release, targeted delivery, and enhanced mechanical properties. They hold promise in cardiac regeneration, joint diseases, postoperative analgesia, and ocular disorder treatment. Hydrogels enriched with nano-hydroxyapatite show potential in bone regeneration, addressing challenges of bone defects, osteoporosis, and tumor-associated regeneration. In wound management and cancer therapy, they enable controlled release, accelerated wound closure, and targeted drug delivery. Injectable hydrogels also find applications in ischemic brain injury, tissue regeneration, cardiovascular diseases, and personalized cancer immunotherapy. This manuscript highlights the versatility and potential of injectable hydrogel nanocomposites in biomedical research. Moreover, it includes a perspective section that explores future prospects, emphasizes interdisciplinary collaboration, and underscores the promising future potential of injectable hydrogel nanocomposites in biomedical research and applications.

Polymeric Nanocomposite Hydrogel Scaffolds in Craniofacial Bone Regeneration: A Comprehensive Review

Nanocomposite biomaterials combine a biopolymeric matrix structure with nanoscale fillers. These bioactive and easily resorbable nanocomposites have been broadly divided into three groups, namely natural, synthetic or composite, based on the polymeric origin. Preparing such nanocomposite structures in the form of hydrogels can create a three-dimensional natural hydrophilic atmosphere pivotal for cell survival and new tissue formation. Thus, hydrogel-based cell distribution and drug administration have evolved as possible options for bone tissue engineering and regeneration. In this context, nanogels or nanohydrogels, created by cross-linking three-dimensional polymer networks, either physically or chemically, with high biocompatibility and mechanical properties were introduced as promising drug delivery systems. The present review highlights the potential of hydrogels and nanopolymers in the field of craniofacial tissue engineering and bone regeneration.

Role of FGF-18 in Bone Regeneration

In tissue engineering, three key components are cells, biological/mechanical cues, and scaffolds. Biological cues are normally proteins such as growth factors and their derivatives, bioactive molecules, and the regulators of a gene. Numerous growth factors such as VEGF, FGF, and TGF-β are being studied and applied in different studies. The carriers used to release these growth factors also play an important role in their functioning. From the early part of the 1990s, more research has beenconductedon the role of fibroblast growth factors on the various physiological functions in our body. The fibroblast growth factor family contains 22 members. Fibroblast growth factors such as 2, 9, and 18 are mainly associated with the differentiation of osteoblasts and in bone regeneration. FGF-18 stimulates the PI3K/ERK pathway and smad1/5/8 pathway mediated via BMP-2 by blocking its antagonist, which is essential for bone formation. FGF-18 incorporated hydrogel and scaffolds had showed enhanced bone regeneration. This review highlights these functions and current trends using this growth factor and potential outcomes in the field of bone regeneration.

Highly resilient porous polyurethane composite scaffolds filled with whitlockite for bone tissue engineering

The present work is intended to provide a base for further investigation of the composite scaffolds for bone tissue engineering, and whitlockite/polyurethane (WH/PU) scaffolds, in particular. WH Ca₁₈Mg₂(HPO₄)₂(PO₄)₁₂ was successfully prepared by means of a chemical reaction between Ca(OH)₂, Mg(OH)₂ and H₃PO₄. WH/PU scaffolds were synthesized via in situ polymerization. Synthesized WH particles and WH/PU composite scaffolds were characterized using FTIR, XRD, SEM and EDS. The porosity of scaffolds was calculated by the liquid displacement method. The water contact angle of scaffolds was tested. Mechanical characterization of WH/PU composite scaffolds was evaluated according to monotonic and cyclic compression examination. MC3T3-E1 cells were employed to evaluate the cytocompatibility of scaffolds. The results showed that WH and PU were completely integrated into composite biomaterials. The maximum compressive strength and elastic modulus of WH/PU composite scaffold reached up to 5.2 and 14.1 MPa, respectively. WH/PU composite scaffold had maximum 73% porosity. The minimum contact angle of WH/PU composite scaffold was 89.16°. WH/PU composite scaffolds have a good elasticity. Cyclic compression tests showed that scaffold could recover 90% of its original shape 1 h after removing the load. WH/PU composite scaffolds exhibited a high affinity to MC3T3-E1 cells. WH/PU composite scaffolds significantly promoted proliferation and alkaline phosphatase activity of MC3T3-E1 cells when compared to those grown on tissue culture well plates. It is suggested that the WH/PU scaffolds might be suitable for the application of bone tissue engineering.

A brief review of mRNA therapeutics and delivery for bone tissue engineering

The therapeutics for bone tissue regeneration requires constant advancements owing to the steady increase in the number of patients suffering from bone-related disorders, and also to find efficient and cost-effective treatment modalities. One of the major advancements in the field of therapeutics is the development of mRNAs. mRNAs, which have been extensively tested for the vaccines, could be very well utilized as a potential inducer for bone regeneration. The ability of mRNAs to enter the cells and instruct the cellular machinery to produce the required native proteins such as BMP or VEGF is a great way to avoid the issues faced with growth factor deliveries such as the production cost, loss of biological function etc. However, there have been a few hurdles for using mRNAs as an effective therapeutic agent, such as proper dosing, tolerating the degradation by RNases, improving the half-life, controlling the spatio-temporal release and reducing the off-target effects. This brief review discusses the various developments in the field of mRNA therapeutics especially for bone tissue engineering, how nano-formulations are being developed to effectively deliver the mRNAs into the cells by evading the immune responses, how researchers have developed certain strategies to increase the half-life, to successfully deliver the mRNAs to specific bone defect area and bring about effective bone regeneration.

RGD-incorporated biomimetic cryogels for hyaline cartilage regeneration

Maintaining the integrity of articular cartilage is paramount to joint health and function. Under constant mechanical stress, articular cartilage is prone to injury that often extends to the underlying subchondral bone. In this study, we incorporated arginine-aspartate-glycine (RGD) peptide into chondroitin sulfate-based cryogel for hyaline cartilage regeneration. Known to promote cell adhesion and proliferation, RGD peptide is a double-edged sword for cartilage regeneration. Depending on the peptide availability in the microenvironment, RGD may aid in redifferentiation of dedifferentiated chondrocytes by mimicking physiological cell-matrix interaction or inhibit chondrogenic phenotype via excessive cell spreading. Here, we observed an increase in chondrogenic phenotype with RGD concentration. The group containing the highest RGD concentration (3 mM; RGD group) experienced a 24-fold increase inCOL2expression in the 1st week ofin vitroculture and formed native cartilage-resembling ectopic tissuein vivo. No sign of dedifferentiation (COL1) was observed in all groups. Within the concentration range tested (0-3 mM RGD), RGD promotes chondrocyte redifferentiation after monolayer expansion and thus, formation of hyaline cartilage tissue.

Peculiarities of the formation, structural and morphological properties of zinc whitlockite (Ca18Zn2(HPO4)2(PO4)12) synthesized via a phase transformation process under hydrothermal conditions

In the present work, the formation of zinc whitlockite via a dissolution–precipitation process was investigated in detail. The influence of medium pH, reaction time, temperature and concentration of precursors on the formation of the material was studied.

Silicon Nitride, a Bioceramic for Bone Tissue Engineering: A Reinforced Cryogel System With Antibiofilm and Osteogenic Effects

Silicon nitride (SiN [Si3N4]) is a promising bioceramic for use in a wide variety of orthopedic applications. Over the past decades, it has been mainly used in industrial applications, such as space shuttle engines, but not in the medical field due to scarce data on the biological effects of SiN. More recently, it has been increasingly identified as an emerging material for dental and orthopedic implant applications. Although a few reports about the antibacterial properties and osteoconductivity of SiN have been published to date, there have been limited studies of SiN-based scaffolds for bone tissue engineering. Here, we developed a silicon nitride reinforced gelatin/chitosan cryogel system (SiN-GC) by loading silicon nitride microparticles into a gelatin/chitosan cryogel (GC), with the aim of producing a biomimetic scaffold with antibiofilm and osteogenic properties. In this scaffold system, the GC component provides a hydrophilic and macroporous environment for cells, while the SiN component not only provides antibacterial properties and osteoconductivity but also increases the mechanical stiffness of the scaffold. This provides enhanced mechanical support for the defect area and a better osteogenic environment. First, we analyzed the scaffold characteristics of SiN-GC with different SiN concentrations, followed by evaluation of its apatite-forming capacity in simulated body fluid and protein adsorption capacity. We further confirmed an antibiofilm effect of SiN-GC against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as well as enhanced cell proliferation, mineralization, and osteogenic gene upregulation for MC3T3-E1 pre-osteoblast cells. Finally, we developed a bioreactor to culture cell-laden scaffolds under cyclic compressive loading to mimic physiological conditions and were able to demonstrate improved mineralization and osteogenesis from SiN-GC. Overall, we confirmed the antibiofilm and osteogenic effect of a silicon nitride reinforced cryogel system, and the results indicate that silicon nitride as a biomaterial system component has a promising potential to be developed further for bone tissue engineering applications.

Injectable nanocomposite hydrogels as an emerging platform for biomedical applications: A review

Hydrogels have attracted much attention for biomedical and pharmaceutical applications due to the similarity of their biomimetic structure to the extracellular matrix of natural living tissues, tunable soft porous microarchitecture, superb biomechanical properties, proper biocompatibility, etc. Injectable hydrogels are an exciting type of hydrogels that can be easily injected into the target sites using needles or catheters in a minimally invasive manner. The more comfortable use, less pain, faster recovery period, lower costs, and fewer side effects make injectable hydrogels more attractive to both patients and clinicians in comparison to non-injectable hydrogels. However, it is difficult to achieve an ideal injectable hydrogel using just a single material (i.e., polymer). This challenge can be overcome by incorporating nanofillers into the polymeric matrix to engineer injectable nanocomposite hydrogels with combined or synergistic properties gained from the constituents. This work aims to critically review injectable nanocomposite hydrogels, their preparation methods, properties, functionalities, and versatile biomedical and pharmaceutical applications such as tissue engineering, drug delivery, and cancer labeling and therapy. The most common natural and synthetic polymers as matrices together with the most popular nanomaterials as reinforcements, including nanoceramics, carbon-based nanostructures, metallic nanomaterials, and various nanosized polymeric materials, are highlighted in this review.

Three-dimensional-poly(lactic acid) scaffolds coated with gelatin/magnesium-doped nano-hydroxyapatite for bone tissue engineering

BACKGROUND

Treatment of critical-sized bone defects has progressively evolved over the years from metallic implants to more ingenious three-dimensional-based scaffolds. The use of three-dimensional scaffolds for bone regeneration from biodegradable polymers like poly(lactic acid) (PLA) is gaining popularity. Scaffolds with surface functionalization using gelatin (Gel) have the advantages of biocompatibility and cell adhesion. Nano-hydroxyapatite (nHAp) is one of the most promising implant materials utilized in orthopaedics. The osteogenic potential of the nHAp can be improved by the substitution of magnesium (Mg) ions onto the crystal lattice of nHAp. Thus, the goal of this work was to make three-dimensional-PLA scaffolds covered with Gel/Mg-nHAp for osteogenic effect.

METHODS AND RESULTS

The designed three-dimensional-PLA/Gel/Mg-nHAp scaffolds were attributed to various characterizations for the examination of their physicochemical, mechanical properties, cyto-compatibility, and biodegradability as well as their ability to promote osteogenesis in vitro. Mouse mesenchymal stem cells (mMSCs) were cytocompatible with these scaffolds. The osteogenic potential of three-dimensional-PLA/Gel/Mg-nHAp scaffolds employing mMSCs was validated at the cellular and molecular levels. The three-dimensional-PLA/Gel/Mg-nHAp scaffolds stimulated the differentiation of mMSCs towards osteoblastic lineage.

CONCLUSION

Based on these findings, we suggest that the three-dimensional-PLA/Gel/Mg-nHAp scaffolds' osteogenic capability may be advantageous in the mending of bone defects in orthopedic applications.

Whitlockite-Enabled Hydrogel for Craniofacial Bone Regeneration

Growth-factor-free bone regeneration remains a challenge in craniofacial engineering. Here, we engineered an osteogenic niche composed of a commercially modified alginate hydrogel and whitlockite microparticles (WHMPs), which impart tunable physicochemical properties that can direct osteogenesis of human gingival mesenchymal stem cells (GMSCs). Our in vitro studies demonstrate that WHMPs induce osteogenesis of GMSCs more effectively than previously demonstrated hydroxyapatite microparticles (HApMPs). Alginate-WHMP hydrogels showed higher elasticity without any adverse effects on the viability of the encapsulated GMSCs. Moreover, the alginate-WHMP hydrogels upregulate the mitogen-activated protein kinase (MAPK) pathway, which in turn orchestrates several osteogenic markers, such as RUNX2 and OCN, in the encapsulated GMSCs. Concurrent coculture studies with human osteoclasts demonstrate that GMSCs encapsulated in alginate-WHMP hydrogels downregulate osteoclastic activity, potentially due to release of Mg2+ ions from the WHMPs along with secretion of osteoprotegerin from the GMSCs. In vivo studies demonstrated that the GMSCs encapsulated in our osteogenic niche were able to promote bone repair in calvarial defects in murine models. Altogether, our results confirmed the development of a promising treatment modality for craniofacial bone regeneration based on an injectable growth-factor-free hydrogel delivery system.

Mussel-Inspired Bisphosphonated Injectable Nanocomposite Hydrogels with Adhesive, Self-Healing, and Osteogenic Properties for Bone Regeneration

Injectable hydrogels have received much attention because of the advantages of simulation of the natural extracellular matrix, microinvasive implantation, and filling and repairing of complex shape defects. Yet, for bone repair, the current injectable hydrogels have shown significant limitations such as the lack of tissue adhesion, deficiency of self-healing ability, and absence of osteogenic activity. Herein, a strategy to construct mussel-inspired bisphosphonated injectable nanocomposite hydrogels with adhesive, self-healing, and osteogenic properties is developed. The nano-hydroxyapatite/poly(l-glutamic acid)-dextran (nHA/PLGA-Dex) dually cross-linked (DC) injectable hydrogels are fabricated via Schiff base cross-linking and noncovalent nHA-BP chelation. The chelation between bisphosphonate ligands (alendronate sodium, BP) and nHA favors the uniform dispersion of the latter. Moreover, multiple adhesion ligands based on catechol motifs, BP, and aldehyde groups endow the hydrogels with good tissue adhesion. The hydrogels possess excellent biocompatibility and the introduction of BP and nHA both can effectively promote viability, proliferation, migration, and osteogenesis differentiation of MC3T3-E1 cells. The incorporation of BP groups and HA nanoparticles could also facilitate the angiogenic property of endothelial cells. The nHA/PLGA-Dex DC hydrogels exhibited considerable biocompatibility despite the presence of a certain degree of inflammatory response in the early stage. The successful healing of a rat cranial defect further proves the bone regeneration ability of nHA/PLGA-Dex DC injectable hydrogels. The developed tissue adhesive osteogenic injectable nHA/PLGA-Dex hydrogels show significant potential for bone regeneration application.

Addition of lactoferrin and substance P in a chitin/PLGA-CaSO4 hydrogel for regeneration of calvarial bone defects

Calcium-based injectable hydrogels with various bioactive active molecules possess a great potential for bone regeneration. Herein, we have synthesized a chitin-PLGA-calcium sulfate hydrogel (CSG) containing bioactive molecules - lactoferrin (LF) and substance P (SP). SEM and XRD analysis revealed that CS crystal growth was altered with the addition of LF. Rheological measurements indicated that the injectability of the hydrogels was maintained after the addition of LF, however, there was a reduction in storage modulus after LF addition. The addition of LF increased stem cell proliferation whereas, SP enhanced the cell migration. Osteogenic gene expression revealed that LF concentration at 25 μg/mg of CSG was optimal for a favourable outcome. To this optimized LF containing CSG, SP was incorporated and 0.05 μg/mg was found to be most effective (CSG-L3S2) in vitro studies. Further, the μ-CT and histological studies confirmed that CSG-L3S2 showed enhanced bone regeneration compared to the controls in critical-sized calvarial defect of mice. Thus the results indicate that a combination of the chemotactic agent (SP), pleiotropic growth protein (LF), and CS in the chitin-PLGA hydrogel could be a promising approach for non-load bearing bone defects.