Bioactive hydrogel-nanosilica hybrid materials: a potential injectable scaffold for bone tissue engineering

Photo-triggered caffeic acid delivery via psyllium polysaccharide- gellan gum-based injectable bionanogel for epidermoid carcinoma treatment

Here, the simultaneous effect of chemo- and photothermal therapy against epidermoid carcinoma (EC) was investigated. A novel hydrogel, termed bionanogel (BNG), was designed using psyllium mucilage polysaccharide and bacterial gellan gum, incorporated with nanocomplex carrying caffeic acid (CA) and IR-820, and further characterized. The dual effect of BNG and 808 nm laser (BNG + L) on EC was investigated. Staining and scratch assays were performed to analyze their therapeutic effect on EC. In vivo evaluations of BNG + L in xenograft models were performed. Rapid transition, limited swelling, degradability and high tensile strength indicated BNG stability and sustained drug release. Irradiation with 808 nm laser light at 1.25 W /cm2 for 4 min resulted in a temperature increase of 53 °C and facilitated cell ablation. The in vitro studies showed that BNG + L suppressed cancer progression via a late apoptotic effect. The in vivo study showed that the slow release of CA from BNG + L significantly attenuated EC with low mitotic index and downregulation of proteins involved in cancer proliferation such as EGFR, AKT, PI3K, ERK, mTOR and HIF-1α. Thus, BNG could be a novel medium for targeted and controlled drug delivery for the treatment of epidermoid cancer when triggered by NIR light.

Novel Fe3O4 Nanoparticles with Bioactive Glass-Naproxen Coating: Synthesis, Characterization, and In Vitro Evaluation of Bioactivity

Immune response to biomaterials, which is intimately related to their surface properties, can produce chronic inflammation and fibrosis, leading to implant failure. This study investigated the development of magnetic nanoparticles coated with silica and incorporating the anti-inflammatory drug naproxen, aimed at multifunctional biomedical applications. The synthesized nanoparticles were characterized using various techniques that confirmed the presence of magnetite and the formation of a silica-rich bioactive glass (BG) layer. In vitro studies demonstrated that the nanoparticles exhibited bioactive properties, forming an apatite surface layer when immersed in simulated body fluid, and biocompatibility with bone cells, with good viability and alkaline phosphatase activity. Naproxen, either free or encapsulated, reduced nitric oxide production, an inflammatory marker, while the BG coating alone did not show anti-inflammatory effects in this study. Overall, the magnetic nanoparticles coated with BG and naproxen showed promise for biomedical applications, especially anti-inflammatory activity in macrophages and in the bone field, due to their biocompatibility, bioactivity, and osteogenic potential.

Construction of a PEGDA/chitosan hydrogel incorporating mineralized copper-doped mesoporous silica nanospheres for accelerated bone regeneration

Hydrogels, integrating diverse biocompatible materials, have emerged as promising candidates for bone repair applications. This study presents a double network hydrogel designed for bone tissue engineering, combining poly(ethylene glycol) diacrylate (PEGDA) and chitosan (CS) crosslinked through UV polymerization and ionic crosslinking. Concurrently, copper-doped mesoporous silica nanospheres (Cu-MSNs) were synthesized using a one-pot method. Cu-MSNs underwent additional modification through in-situ biomineralization, resulting in the formation of an apatite layer. Polydopamine was employed to facilitate the deposition of Calcium (Ca) and Phosphate (P) ions on the surface of Cu-MSNs (Cu-MSNs/PDA@CaP). Composite hydrogels were created by integrating varied concentrations of Cu-MSNs/PDA@CaP (25, 50, 100, 150, 200 μg/mL). Characterization unveiled distinctive interconnected porous structures within the composite hydrogel, showcasing a notable 169.6 % enhancement in compressive stress (elevating from 89.01 to 240.19 kPa) compared to pure PEGDA. In vitro biocompatibility experiments illustrated that the composite hydrogel maintained elevated cell viability (up to 106.6 %) and facilitated rapid cell proliferation over 7 days. The hydrogel demonstrated a substantial 57.58 % rise in ALP expression and a surprising 235.27 % increase in ARS staining. Moreover, it significantly enhanced the expression of crucial osteogenic genes, such as run-related transcription factors 2 (RUNX2), collagen 1a1 (Col1a1), and secreted phosphoprotein 1 (Spp1), establishing it as a promising scaffold for bone regeneration. This study shows how Cu-MSNs/PDA@CaP were successfully integrated into a double network hydrogel, resulting in a composite material with good biological responses. Due to its improved characteristics, this composite hydrogel holds the potential for advancing bone regeneration procedures.

Fucoidan-Coated Silica Nanoparticles Promote the Differentiation of Human Mesenchymal Stem Cells into the Osteogenic Lineage

Silica nanoparticles (SiNPs) are widely used in biomedical applications, such as cancer therapy/diagnosis or tissue engineering and regenerative medicine. Herein, we synthesized SiNPs and modified them with sulfonic acid groups (by organosilylation followed by oxidation) or a sulfated polysaccharide (i.e., fucoidan, a seaweed biopolymer, by using electrostatic surface immobilization) due to the known capacity of the sulfonic/sulfate moieties to stabilize proteins and promote stem cell differentiation toward the osteogenic lineage. The developed pristine and functionalized nanoparticles were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), showing the monodisperse size distribution (between 360 and 450 nm) and the success of the coating/functionalization with fucoidan or sulfonic groups. The developed SiNPs (at a concentration of 50 μg/mL) were assessed through their contact with SaOs2 cells evidencing their cytocompatibility. Furthermore, the osteogenic differentiation of bmMSCs was evaluated by the quantification of ALP activity, as well as the expression profile of osteogenic-related genes, such as Runx2, ALP, and OP. We found that the coating of the SiNPs with fucoidan induced the osteogenic differentiation of bmMSCs, being an effective mediator of bone regeneration.

The Diamond Concept Enigma: Recent Trends of Its Implementation in Cross-linked Chitosan-Based Scaffolds for Bone Tissue Engineering

An increasing number of publications over the past ten years have focused on the development of chitosan-based cross-linked scaffolds to regenerate bone tissue. The design of biomaterials for bone tissue engineering applications relies heavily on the ideals set forth by a polytherapy approach called the "Diamond Concept". This methodology takes into consideration the mechanical environment, scaffold properties, osteogenic and angiogenic potential of cells, and benefits of osteoinductive mediator encapsulation. The following review presents a comprehensive summarization of recent trends in chitosan-based cross-linked scaffold development within the scope of the Diamond Concept, particularly for nonload-bearing bone repair. A standardized methodology for material characterization, along with assessment of in vitro and in vivo potential for bone regeneration, is presented based on approaches in the literature, and future directions of the field are discussed.

Bacterial collagen-templated synthesis and assembly of inorganic particles

Collagen has been used as a common template for mineralization and assembly of inorganic particles, because of the special arrangement of its fibrils and the presence of charged residues. Streptococcal bacterial collagen, which is inherently secreted on the surface ofStreptococcus pyogenes, has been progressively used as an alternative for type I animal collagen. Bacterial collagen is rich in charged amino acids, which can act as a substrate for the nucleation and growth of inorganic particles. Here, we show that bacterial collagen can be used to nucleate three different inorganic materials: hydroxyapatite crystals, silver nanoparticles, and silica nanoparticles. Collagen/mineral composites show an even distribution of inorganic particles along the collagen fibers, and the particles have a more homogenous size compared with minerals that are formed in the absence of the collagen scaffold. Furthermore, the gelation of silica occurring during mineralization represents a means to produce processable self-standing collagen composites, which is challenging to achieve with bacterial collagen alone. Overall, we highlight the advantage of simply combining bacterial collagen with minerals to expand their applications in the fields of biomaterials and tissue engineering, especially for bone regenerative scaffolds.

Composite Materials Based on Gelatin and Iron Oxide Nanoparticles for MRI Accuracy

The majority of recent studies have focused on obtaining MRI materials for internal use. However, this study focuses on a straightforward method for preparing gelatin-based materials with iron oxide nanoparticles (G–Fe₂O₃ and G–Fe₃O₄) for external use. The newly obtained materials must be precisely tuned to match the requirements and usage situation because they will be in close touch with human/animal skin. The biocompatible structures formed by gelatin, tannic acid, and iron oxide nanoparticles were investigated by using FTIR spectroscopy, SEM-EDAX analysis, and contact angle methods. The physico-chemical properties were obtained by using mechanical investigations, dynamic vapor sorption analysis, and bulk magnetic determination. The size and shape of iron oxide nanoparticles dictates the magnetic behavior of the gelatin-based samples. The magnetization curves revealed a typical S-shaped superparamagnetic behavior which is evidence of improved MRI image accuracy. In addition, the MTT assay was used to demonstrate the non-toxicity of the samples, and the antibacterial test confirmed satisfactory findings for all G-based materials.

Lysine-functionalized chondroitin sulfate improves the biological properties of collagen/chitosan-based injectable hydrogels

Novel bioactive collagen/chitosan/lysine-functionalized chondroitin sulfate (CS_mod) injectable hydrogels are presented. The modification of CS with amine groups introduced with lysine moieties (the degree of substitution about 21%) guarantees its covalent binding with the hydrogel network while genipin crosslinking. Both the physicochemical and biological features of developed hydrogels might be adjusted by playing with CS_mod and crosslinking agent concentrations. It was revealed that materials became more hydrophobic with increased CS_mod content, while crosslinking degree and enzymatic degradation studies established the influence of CS_mod concentration and Ch:CS_mod ratio on the crosslinking process. In situ rheological experiments verified the injectability of resulted systems. The biological in vitro evaluation demonstrated that all designed materials are biocompatible as they supported proliferation and adhesion of MG-63 cell line. In vitro biomineralization study employing simulated body fluid model revealed CS_mod-content dependent bioactivity of obtained hydrogels. Importantly for pristine collagen/chitosan materials, the formation of apatite-like structures was not observed. Our findings demonstrate that developed injectable ColChCS_mod hydrogels particularly system with the greatest CS_mod concentration exhibits high bioactive potential, without the need of applying additional inducers what renders them promising materials within 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.

Advanced bioactive nanomaterials for biomedical applications

Bioactive materials are a kind of materials with unique bioactivities, which can change the cellular behaviors and elicit biological responses from living tissues. Bioactive materials came into the spotlight in the late 1960s when the researchers found that the materials such as bioglass could react with surrounding bone tissue for bone regeneration. In the following decades, advances in nanotechnology brought the new development opportunities to bioactive nanomaterials. Bioactive nanomaterials are not a simple miniaturization of macroscopic materials. They exhibit unique bioactivities due to their nanoscale size effect, high specific surface area, and precise nanostructure, which can significantly influence the interactions with biological systems. Nowadays, bioactive nanomaterials have represented an important and exciting area of research. Current and future applications ensure that bioactive nanomaterials have a high academic and clinical importance. This review summaries the recent advances in the field of bioactive nanomaterials, and evaluate the influence factors of bioactivities. Then, a range of bioactive nanomaterials and their potential biomedical applications are discussed. Furthermore, the limitations, challenges, and future opportunities of bioactive nanomaterials are also discussed.

Addressing the Osteoporosis Problem-Multifunctional Injectable Hybrid Materials for Controlling Local Bone Tissue Remodeling

Novel multifunctional biomimetic injectable hybrid systems were synthesized. The physicochemical as well as biological in vitro and in vivo tests demonstrated that they are promising candidates for bone tissue regeneration. The hybrids are composed of a biopolymeric collagen/chitosan/hyaluronic acid matrix and amine group-functionalized silica particles decorated with apatite to which the alendronate molecules were coordinated. The components of these systems were integrated and stabilized by cross-linking with genipin, a compound of natural origin. They can be precisely injected into the diseased tissue in the form of a viscous sol or a partially cross-linked hydrogel, where they can serve as scaffolds for locally controlled bone tissue regeneration/remodeling by supporting the osteoblast formation/proliferation and maintaining the optimal osteoclast level. These materials lack systemic toxicity. They can be particularly useful for the repair of small osteoporotic bone defects.

A Systematic Review of Tissue Engineering Scaffold in Tendon Bone Healing in vivo

Background: Tendon-bone healing is an important factor in determining the success of ligament reconstruction. With the development of biomaterials science, the tissue engineering scaffold plays an extremely important role in tendon-bone healing and bone tissue engineering. Materials and Methods: Electronic databases (PubMed, Embase, and the Web of Science) were systematically searched for relevant and qualitative studies published from 1 January 1990 to 31 December 2019. Only original articles that met eligibility criteria and evaluated the use of issue engineering scaffold especially biomaterials in tendon bone healing in vivo were selected for analysis. Results: The search strategy identified 506 articles, and 27 studies were included for full review including two human trials and 25 animal studies. Fifteen studies only used biomaterials like PLGA, collage, PCL, PLA, and PET as scaffolds to repair the tendon-bone defect, on this basis, the rest of the 11 studies using biological interventions like cells or cell factors to enhance the healing. The adverse events hardly ever occurred, and the tendon bone healing with tissue engineering scaffold was effective and superior, which could be enhanced by biological interventions. Conclusion: Although a number of tissue engineering scaffolds have been developed and applied in tendon bone healing, the researches are mainly focused on animal models which are with limitations in clinical application. Since the efficacy and safety of tissue engineering scaffold has been proved, and can be enhanced by biological interventions, substantial clinical trials remain to be done, continued progress in overcoming current tissue engineering challenges should allow for successful clinical practice.

Recent advances in the application of mesoporous silica-based nanomaterials for bone tissue engineering

Silica nanomaterials (SNMs) and their composites have recently been investigated as scaffolds for bone tissue engineering. SNM scaffolds possess the ability to encourage bone cell growth and also allow the simultaneous delivery of biologically active biomolecules that are encapsulated in the mesopores. Their high mechanical strength, low cytotoxicity, ability to stimulate both the proliferation and osteogenic differentiation of progenitor cells make the SNMs appropriate scaffolds. Their physiochemical properties facilitate the cell spreading process, allow easy access to nutrients and help the cell-cell communication process during bone tissue engineering. The ability to deliver small biomolecules, such as dexamethasone, different growth factors, vitamins and mineral ions depends on the morphology, porosity, and crystallinity of SNMs and their composites with other polymeric materials. In this review, the abilities of SNMs to perform as suitable scaffolds for bone tissue engineering are comprehensively discussed.

Preparation and effect of lyophilized platelet-rich fibrin on the osteogenic potential of bone marrow mesenchymal stem cells in vitro and in vivo

Objectives

The goal of this study was to prepare lyophilized platelet-rich fibrin (L-PRF) and analyze the combined use of L-PRF and osteogenic bone marrow mesenchymal stem cell (BMSC) sheet fragments for bone tissue engineering via in vivo injection.

Methods

First, fresh PRF (F-PRF) was lyophilized to prepare L-PRF, the characteristics of which were examined through gross morphological, and histological and microstructural observations. In addition, the kinetics of growth factor release from L-PRF and F-PRF were also determined by enzyme-linked immunosorbent assay (ELISA). Subsequently, after assessing the proliferation and osteogenic differentiation of BMSCs exposed to L-PRF or F-PRF in vitro, we subcutaneously injected BMSC sheet fragments with L-PRF or F-PRF into nude mice and assessed bone formation through microcomputed tomography and histological analyses.

Results

We observed that L-PRF released growth factors that favored BMSC proliferation and osteogenic differentiation in vitro. The combined use of L-PRF and osteogenic BMSC sheet fragments enabled bone tissue regeneration in vivo, and no significant difference between the F-PRF and L-PRF groups was observed (P = 0.24).

Conclusions

The results of this study demonstrate that the combined use of L-PRF and osteogenic BMSC sheets may have potential in the fabrication of engineered bone.

Modification of Titanium Implant and Titanium Dioxide for Bone Tissue Engineering

Bone tissue engineering using titanium (Ti) implant and titanium dioxide (TiO₂) with their modification is gaining increasing attention. Ti has been adopted as an implant material in dental and orthopedic fields due to its superior properties. However, it still requires modification in order to achieve robust osteointegration between the Ti implant and surrounding bone. To modify the Ti implant, numerous methods have been introduced to fabricate porous implant surfaces with a variety of coating materials. Among these, plasma spraying of hydroxyapatite (HA) has been the most commonly used with commercial success. Meanwhile, TiO₂ nanotubes have been actively studied as the coating material for implants, and promising results have been reported about improving osteogenic activity around implants recently. Also porous three-dimensional constructs based on TiO₂ have been proposed as scaffolding material with high biocompatibility and osteoconductivity in large bone defects. However, the use of the TiO₂ scaffolds in load-bearing environment is somewhat limited. In order to optimize the TiO₂ scaffolds, studies have tried to combine various materials with TiO₂ scaffolds including drug, mesenchymal stem cells, Al₂O₃-SiO₂ solid and HA. This article will shortly introduce the properties of Ti and Ti-based implants with their modification, and review the progress of bone tissue engineering using the TiO₂ nanotubes and scaffolds.

Genipin crosslinked bioactive collagen/chitosan/hyaluronic acid injectable hydrogels structurally amended via covalent attachment of surface-modified silica particles

Collagen, chitosan and hyaluronic acid based multicomponent injectable and in situ gellating biomimetic hybrid materials for bone tissue engineering applications were prepared in one-step procedure. The bioactive phase in the form of surface-modified silica particles was introduced to the solutions of biopolymers and simultaneously crosslinked with genipin both the biopolymer matrix and dispersed particles at 37 °C. The novel approach presented here involved the use of silica particles which surfaces were priory functionalized with amino groups. That modification makes possible the covalent attachment of silica particles to the polymeric hydrogel network on crosslinking with genipin. That methodology is especially important as it makes possible to obtain the hybrid materials (biopolymer-silica particles) in which the problems related to the potential phase separation of mineral particles, hindering their in vivo application can be eliminated. The hybrids of various compositions were obtained and their physicochemical and biological properties were determined. The in vitro experiments performed under simulated body fluid conditions revealed that the amino-functionalized silica particles covalently attached to the biopolymeric network are still bioactive. Finally, the in vitro cell culture studies shown that the materials developed are biocompatible as they supported MG-63 cells adhesion, proliferation as well as Alkaline phosphatase (ALP) expression.

Anti-inflammatory and antimicrobial activity of bioactive hydroxyapatite/silver nanocomposites

Biomaterials are often used in orthopedic surgery like cavity fillings. However, related complications often require long-term systemic antibiotics, device removal, and extended rehabilitation. Hydroxyapatite/silver (HA/Ag) composites have been proposed as implantation biomaterials owing to the osteogenic properties of hydroxyapatite and to the antimicrobial efficiency of silver. Nevertheless, higher silver concentrations induce cytotoxic effects. The aim of this study was to synthesize and characterize HA/Ag nanocomposites that will allow us to use lower concentrations of silver nanoparticles with better antimicrobial efficiency and anti-inflammatory properties. The characterization of HA/Ag was performed by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, and laser diffraction. Bioactivity was evaluated under a simulated body fluid. The viability of osteoblast like-cells (MG-63) was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) and the antimicrobial activity was evaluated by the standard McFarland method. The detection of nitric oxide was measured by a colorimetric assay and the inflammatory cytokines by flow cytometry. We obtained particulate composites of calcium phosphates identified as hydroxyapatite and silver nanoparticles. The bioactivity of the HA/Ag nanocomposites on SFB was confirmed by apatite formations. The viability of MG-63 cells was not affected. We also found antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans owing to the presence of silver nanoparticles at non-cytotoxic concentrations. HA/Ag reduced the release of nitric oxide and decreased the secretion of IL-1 and TNF-α in cells stimulated with Lipopolysaccharide (LPS). In conclusion, the inflammatory and antimicrobial capacity of the HA/Ag nanocomposites, as well as its bioactivity and low cytotoxicity make it a candidate as an implantation biomaterial for bone tissues engineering and clinical practices in orthopedic, oral and maxillofacial surgery.

Effects of Silicon Compounds on Biomineralization, Osteogenesis, and Hard Tissue Formation

Bioinspired stem cell-based hard tissue engineering includes numerous aspects: The synthesis and fabrication of appropriate scaffold materials, their analytical characterization, and guided osteogenesis using the sustained release of osteoinducing and/or osteoconducting drugs for mesenchymal stem cell differentiation, growth, and proliferation. Here, the effect of silicon- and silicate-containing materials on osteogenesis at the molecular level has been a particular focus within the last decade. This review summarizes recently published scientific results, including material developments and analysis, with a special focus on silicon hybrid bone composites. First, the sources, bioavailability, and functions of silicon on various tissues are discussed. The second focus is on the effects of calcium-silicate biomineralization and corresponding analytical methods in investigating osteogenesis and bone formation. Finally, recent developments in the manufacturing of Si-containing scaffolds are discussed, including in vitro and in vivo studies, as well as recently filed patents that focus on the influence of silicon on hard tissue formation.

Bioactive glass ions induce efficient osteogenic differentiation of human adipose stem cells encapsulated in gellan gum and collagen type I hydrogels

BACKGROUND

Due to unmet need for bone augmentation, our aim was to promote osteogenic differentiation of human adipose stem cells (hASCs) encapsulated in gellan gum (GG) or collagen type I (COL) hydrogels with bioactive glass (experimental glass 2-06 of composition [wt-%]: Na₂O 12.1, K₂O 14.0, CaO 19.8, P₂O5 2.5, B₂O₃ 1.6, SiO₂ 50.0) extract based osteogenic medium (BaG OM) for bone construct development. GG hydrogels were crosslinked with spermidine (GG-SPD) or BaG extract (GG-BaG).

METHODS

Mechanical properties of cell-free GG-SPD, GG-BaG, and COL hydrogels were tested in osteogenic medium (OM) or BaG OM at 0, 14, and 21 d. Hydrogel embedded hASCs were cultured in OM or BaG OM for 3, 14, and 21 d, and analyzed for viability, cell number, osteogenic gene expression, osteocalcin production, and mineralization. Hydroxyapatite-stained GG-SPD samples were imaged with Optical Projection Tomography (OPT) and Selective Plane Illumination Microscopy (SPIM) in OM and BaG OM at 21 d. Furthermore, Raman spectroscopy was used to study the calcium phosphate (CaP) content of hASC-secreted ECM in GG-SPD, GG-BaG, and COL at 21 d in BaG OM.

RESULTS

The results showed viable rounded cells in GG whereas hASCs were elongated in COL. Importantly, BaG OM induced significantly higher cell number and higher osteogenic gene expression in COL. In both hydrogels, BaG OM induced strong mineralization confirmed as CaP by Raman spectroscopy and significantly improved mechanical properties. GG-BaG hydrogels rescued hASC mineralization in OM. OPT and SPIM showed homogeneous 3D cell distribution with strong mineralization in BaG OM. Also, strong osteocalcin production was visible in COL.

CONCLUSIONS

Overall, we showed efficacious osteogenesis of hASCs in 3D hydrogels with BaG OM with potential for bone-like grafts.

Inorganic polymerization: an attractive route to biocompatible hybrid hydrogels

The sol–gel process is one of the main techniques leading to hybrid hydrogels that can be used in a wide scope of applications, especially in the biomedical field.

Facile Fabrication of Composite Electrospun Nanofibrous Matrices of Poly(ε-caprolactone)-Silica Based Pickering Emulsion

Functionalized matrices have been sought for their application in sensors, filtration, energy storage, catalysis, and tissue engineering. We report formation of an inorganic-organic composite matrix based on poly(ε-caprolactone) (PCL) functionalized with hydrophobically modified silica (m-silica) fabricated with reduced organic solvent usage. The matrix was obtained via electrospinning of a water-in-oil emulsion of PCL that was stabilized by judicious choice of m-silica as a Pickering agent resulting into an emulsifier free matrix. Inclusion of m-silica in PCL matrix resulted in enhancing tensile properties and cell proliferation efficiency. The electrospun composite matrix was free from any emulsifier or template polymer; thus any abrupt loss in mechanical properties was prevented when the matrix was subjected to aqueous conditions. The inorganic-organic biodegradable composite matrices thus produced using an emulsifier free emulsion find applications in tissue engineering and may further be evaluated for other areas including selective sorption and separation.

Injectable hydrogels for cartilage and bone tissue engineering

Tissue engineering has become a promising strategy for repairing damaged cartilage and bone tissue. Among the scaffolds for tissue-engineering applications, injectable hydrogels have demonstrated great potential for use as three-dimensional cell culture scaffolds in cartilage and bone tissue engineering, owing to their high water content, similarity to the natural extracellular matrix (ECM), porous framework for cell transplantation and proliferation, minimal invasive properties, and ability to match irregular defects. In this review, we describe the selection of appropriate biomaterials and fabrication methods to prepare novel injectable hydrogels for cartilage and bone tissue engineering. In addition, the biology of cartilage and the bony ECM is also summarized. Finally, future perspectives for injectable hydrogels in cartilage and bone tissue engineering are discussed.

Natural marine sponges for bone tissue engineering: The state of art and future perspectives

Marine life and its rich biodiversity provide a plentiful resource of potential new products for the society. Remarkably, marine organisms still remain a largely unexploited resource for biotechnology applications. Among them, marine sponges are sessile animals from the phylum Porifera dated at least from 580 million years ago. It is known that molecules from marine sponges present a huge therapeutic potential in a wide range of applications mainly due to its antitumor, antiviral, anti-inflammatory, and antibiotic effects. In this context, this article reviews all the information available in the literature about the potential of the use of marine sponges for bone tissue engineering applications. First, one of the properties that make sponges interesting as bone substitutes is their structural characteristics. Most species have an efficient interconnected porous architecture, which allows them to process a significant amount of water and facilitates the flow of fluids, mimicking an ideal bone scaffold. Second, sponges have an organic component, the spongin, which is analogous to vertebral collagen, the most widely used natural polymer for tissue regeneration. Last, osteogenic properties of marine sponges is also highlighted by their mineral content, such as biosilica and other compounds, that are able to support cell growth and to stimulate bone formation and mineralization. This review focuses on recent studies concerning these interesting properties, as well as on some challenges to be overcome in the bone tissue engineering field. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1717-1727, 2017.

Monitoring/Imaging and Regenerative Agents for Enhancing Tissue Engineering Characterization and Therapies

The past three decades have seen numerous advances in tissue engineering and regenerative medicine (TERM) therapies. However, despite the successes there is still much to be done before TERM therapies become commonplace in clinic. One of the main obstacles is the lack of knowledge regarding complex tissue engineering processes. Imaging strategies, in conjunction with exogenous contrast agents, can aid in this endeavor by assessing in vivo therapeutic progress. The ability to uncover real-time treatment progress will help shed light on the complex tissue engineering processes and lead to development of improved, adaptive treatments. More importantly, the utilized exogenous contrast agents can double as therapeutic agents. Proper use of these Monitoring/Imaging and Regenerative Agents (MIRAs) can help increase TERM therapy successes and allow for clinical translation. While other fields have exploited similar particles for combining diagnostics and therapy, MIRA research is still in its beginning stages with much of the current research being focused on imaging or therapeutic applications, separately. Advancing MIRA research will have numerous impacts on achieving clinical translations of TERM therapies. Therefore, it is our goal to highlight current MIRA progress and suggest future research that can lead to effective TERM treatments.

Improved properties of composite collagen hydrogels: protected oligourethanes and silica particles as modulators

This paper reports the structure–property relationship of novel biomedical hydrogels derived from collagen, water-soluble oligourethanes, and silica.

A fluorescent, self-healing and pH sensitive hydrogel rapidly fabricated from HPAMAM and oxidized alginate with injectability

Multifunctional hydrogels were fabricated from HPAMAM and oxidized Alginate via electrostatic force, hydrogen bonds and acylhydrazone bonds. They are injectable, fluorescent, pH sensitive, biodegradable, and also able to release drug and self-heal.

Composites of Polymer Hydrogels and Nanoparticulate Systems for Biomedical and Pharmaceutical Applications

Due to their unique structures and properties, three-dimensional hydrogels and nanostructured particles have been widely studied and shown a very high potential for medical, therapeutic and diagnostic applications. However, hydrogels and nanoparticulate systems have respective disadvantages that limit their widespread applications. Recently, the incorporation of nanostructured fillers into hydrogels has been developed as an innovative means for the creation of novel materials with diverse functionality in order to meet new challenges. In this review, the fundamentals of hydrogels and nanoparticles (NPs) were briefly discussed, and then we comprehensively summarized recent advances in the design, synthesis, functionalization and application of nanocomposite hydrogels with enhanced mechanical, biological and physicochemical properties. Moreover, the current challenges and future opportunities for the use of these promising materials in the biomedical sector, especially the nanocomposite hydrogels produced from hydrogels and polymeric NPs, are discussed.