Hydroxypropylmethyl cellulose (HPMC) crosslinked chitosan (CH) based scaffolds containing bioactive glass (BG) and zinc oxide (ZnO) for alveolar bone repair

A comprehensive review on crosslinked network systems of zinc oxide-organic polymer composites

In recent years, the synergistic crosslinked networks formed by zinc oxide (ZnO) particles and organic polymers have gained significant attention. This importance is ascribed due to the valuable combination of low band gap containing ZnO particles with responsive behavior containing organic polymers. These properties of both ZnO and organic polymers make a suitable system of crosslinked ZnO-organic polymer composite (CZOPC) for various applications in the fields of biomedicine, catalysis, and environmental perspectives. The literature extensively provided the diverse morphologies and structures of CZOPC, and these architectural structures play a crucial role in determining their efficiency across various applications. Consequently, the careful design of CZOPC shapes tailored to specific purposes has become a focal point. This comprehensive review provides insights into the classifications, synthetic approaches, characterizations, and applications of ZnO particles decorated in organic polymers with crosslinked network. The exploration extends to the adsorption, environmental, catalytic, and biomedical applications of ZnO-organic polymer composites. Adopting a tutorial approach, the review systematically investigates and elucidates the applications of CZOPC with a comprehensive understanding of their diverse capabilities and uses.

Development, Evaluation, and Molecular Dynamics Study of Ampicillin-Loaded Chitosan-Hyaluronic Acid Films as a Drug Delivery System

Periodontitis is an inflammatory periodontal disease defined by the progressive loss of tissues surrounding the tooth. Ampicillin is an antibiotic for managing and treating specific bacterial infections, including periodontitis. Periodontal pockets occur due to periodontal disease progression and act as a natural reservoir that is easily reachable for the insertion of a delivery system, and the amount of drug to be released has a major role in the efficiency of treatment of the disease. Polyelectrolyte complexes (PECs), particularly those based on chitosan and hyaluronic acid combinations, offer a promising avenue to overcome the challenges associated with drug delivery. These complexes are both biodegradable and biocompatible, making them an optimal choice for enabling targeted drug delivery. This study centers on developing and assessing the structure and dynamic attributes of a drug-PEC system encompassing ampicillin and chitosan-hyaluronic acid components, which represents a targeted drug delivery system to better alleviate the periodontitis. To achieve this goal, we conducted experiments including weight and drug content uniformity, swelling ındex, drug release %, FT-IR and SEM analyses, and atomistic molecular dynamics simulations on the drug PECs loaded with ampicillin with varying amounts of hyaluronic acid. All simulations and the experimental analysis suggested that increased HA amount resulted in an increase in drug release % and swelling index. The simulation outcomes provide insights into the nature of the drug and PEC interactions alongside transport properties such as drug diffusion coefficients. These coefficients offer valuable insights into the molecular behavior of ampicillin-PEC drug delivery systems, particularly in the context of their application in periodontitis treatment.

Tissue engineered periosteum: Fabrication of a gelatin basedtrilayer composite scaffold with biomimetic properties for enhanced bone healing

The periosteum, a vascularized tissue membrane, is essential in bone regeneration following fractures and bone loss due to some other reasons, yet there exist several research gaps concerning its regeneration. These gaps encompass reduced cellular proliferation and bioactivity, potential toxicity, heightened stiffness of scaffold materials, unfavorable porosity, expensive materials and procedures, and suboptimal survivability or inappropriate degradation rates of the implanted materials. This research used an interdisciplinary approach by forming a new material fabricated through electrospinning for the proposed application as a layer-by-layer tissue-engineered periosteum (TEP). TEP comprises poly(ε-caprolactone) (PCL), PCL/gelatin/magnesium-doped zinc oxide (vascular layer), and gelatin/bioactive glass/COD liver oil (osteoconductive layer). These materials were selected for their diverse properties, when integrated into the scaffold formation, successfully mimic the characteristics of native periosteum. Scanning electron microscopy (SEM) was employed to confirm the trilayer structure of the scaffold and determine the average fiber diameter. In-vitro degradation and swelling studies demonstrated a uniform degradation rate that matches the typical recovery time of periosteum. The scaffold exhibited excellent mechanical properties comparable to natural periosteum. Furthermore, the sustained release kinetics of COD liver oil were observed in the trilayer scaffold. Cell culture results indicated that the three-dimensional topography of the scaffold promoted cell growth, proliferation, and attachment, confirming its non-toxicity, biocompatibility, and bioactivity. This study suggests that the fabricated scaffold holds promise as a potential artificial periosteum for treating periostitis and bone fractures.

Fabrication of Cu/ZnO-loaded chitosan hydrogel for an effective wound dressing material to advanced wound care and healing efficiency after caesarean section surgery

Wound infections and delayed complications after caesarean section surgical procedure to mothers would have a prevalence of discomfort, stress and dissatisfaction in the postpartum period. In this report, one-pot synthesis is used for the preparation of chitosan (CS)-based copper nanoparticles (nCu), which was used for the preparation of zinc oxide (ZnO) hydrogel as wound dressing materials after surgery. The antibacterial activity of (CS-nCu/ZnO) developed hydrogels was studied zone of inhibition, against gram-positive and gram-negative bacteria. The antibacterial activity of the CS-nCu/ZnO hydrogel demonstrated that nanoformulated hydrogel materials have provided excellent bactericidal action against clinically approved bacterial pathogens. The biocompatibility and in vitro wound healing potential of the developed wound closure materials were studied by MTT assay and wound scratch assay methods, respectively. The MTT assay and cell migration assay results demonstrated that CS-nCu/ZnO hydrogel material induces cell compatibility and effective cell proliferation ability. These findings suggest that the CS-nCu/ZnO hydrogel outperforms CS-ZnO in terms of wound healing and could be used as a wound closure material in caesarean section wound treatment.

Mechanical properties, and in vitro biocompatibility assessment of biomimetic dual layered keratin/ hydroxyapatite scaffolds

A novel biomimetic dual layered keratin/hydroxyapatite (keratin/HA) scaffold was designed using iterative freeze-drying technique. The prepared scaffolds were studied using several analytical techniques to better understand the biological, structural, and mechanical properties. The developed multilayered, interconnected, porous keratin scaffold with different hydroxyapatite (HA) content in the outer and inner layer, mimics the inherent gradient structure of alveolar bone. SEM studies showed an interconnected porous architecture of the prepared scaffolds with seamless integration between the upper and lower layers. The incorporation of HA improved the mechanical properties keratin/HA scaffolds. The keratin/HA scaffolds exhibited superior mechanical properties in terms of Young's modulus and compressive strength in comparison to pure keratin scaffolds. The biocompatibility studies suggested that both keratin and keratin/HA scaffolds were cyto-compatible, in terms of cell proliferation. Furthermore, it showed that both the tested materials can served as an ideal substrate for the differentiation of Saos-2 cells, leading to mineralization of the extracellular matrix. In summary, ionic liquid based green technique was employed for keratin extraction to fabricate keratin/HA scaffolds and our detailed in vitro investigations suggest the great potential for these composite scaffolds for bone tissue engineering in future.

Acceptor Engineering Produces Ultrafast Nonradiative Decay in NIR-II Aza-BODIPY Nanoparticles for Efficient Osteosarcoma Photothermal Therapy via Concurrent Apoptosis and Pyroptosis

Small-molecule photothermal agents (PTAs) with intense second near-infrared (NIR-II, 1,000 to 1,700 nm) absorption and high photothermal conversion efficiencies (PCEs) are promising candidates for treating deep-seated tumors such as osteosarcoma. To date, the development of small-molecule NIR-II PTAs has largely relied on fabricating donor-acceptor-donor (D-A-D/D') structures and limited success has been achieved. Herein, through acceptor engineering, a donor-acceptor-acceptor (D-A-A')-structured NIR-II aza-boron-dipyrromethene (aza-BODIPY) PTA (SW8) was readily developed for the 1,064-nm laser-mediated phototheranostic treatment of osteosarcoma. Changing the donor groups to acceptor groups produced remarkable red-shifts of absorption maximums from first near-infrared (NIR-I) regions (~808 nm) to NIR-II ones (~1,064 nm) for aza-BODIPYs (SW1 to SW8). Furthermore, SW8 self-assembled into nanoparticles (SW8@NPs) with intense NIR-II absorption and an ultrahigh PCE (75%, 1,064 nm). This ultrahigh PCE primarily originated from an additional nonradiative decay pathway, which showed a 100-fold enhanced decay rate compared to that shown by conventional pathways such as internal conversion and vibrational relaxation. Eventually, SW8@NPs performed highly efficient 1,064-nm laser-mediated NIR-II photothermal therapy of osteosarcoma via concurrent apoptosis and pyroptosis. This work not only illustrates a remote approach for treating deep-seated tumors with high spatiotemporal control but also provides a new strategy for building high-performance small-molecule NIR-II PTAs.

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.

Cellulose-based composite scaffolds for bone tissue engineering and localized drug delivery

Natural bone constitutes a complex and organized structure of organic and inorganic components with limited ability to regenerate and restore injured tissues, especially in large bone defects. To improve the reconstruction of the damaged bones, tissue engineering has been introduced as a promising alternative approach to the conventional therapeutic methods including surgical interventions using allograft and autograft implants. Bioengineered composite scaffolds consisting of multifunctional biomaterials in combination with the cells and bioactive therapeutic agents have great promise for bone repair and regeneration. Cellulose and its derivatives are renewable and biodegradable natural polymers that have shown promising potential in bone tissue engineering applications. Cellulose-based scaffolds possess numerous advantages attributed to their excellent properties of non-toxicity, biocompatibility, biodegradability, availability through renewable resources, and the low cost of preparation and processing. Furthermore, cellulose and its derivatives have been extensively used for delivering growth factors and antibiotics directly to the site of the impaired bone tissue to promote tissue repair. This review focuses on the various classifications of cellulose-based composite scaffolds utilized in localized bone drug delivery systems and bone regeneration, including cellulose-organic composites, cellulose-inorganic composites, cellulose-organic/inorganic composites. We will also highlight the physicochemical, mechanical, and biological properties of the different cellulose-based scaffolds for bone tissue engineering applications.

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Cellulose and its derivatives are renewable and biodegradable natural polymers that with great potential for bone tissue engineering.

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Cellulose-based materials can be used various therapeutics directly to the bone to achieve bone regeneration.

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Bioinks made of cellulose-based materials hold great promise to develop patient specific solutions for bone repair using 3D printing.

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Challenges associated with inaccuracies in existing preclinical models, sterilization regulatory barriers still need to be addressed before clinical translation.

Comparative review of piezoelectric biomaterials approach for bone tissue engineering

Bone as a minerals' reservoir and rigid tissue of the body generating red and white blood cells supports various organs. Although the self-regeneration property of bone, it cannot regenerate spontaneously in severe damages and still remains as a challenging issue. Tissue engineering offers several techniques for regenerating damaged bones, where various biomaterials are examined to fabricate scaffolds for bone repair. Piezoelectric characteristic plays a crucial role in repairing and regenerating damaged bone by mimicking the bone niche behavior. Piezoelectric biomaterials show significant potential for bone tissue engineering. Herein we try to have a comparative review on piezoelectric and non-piezoelectric biomaterials used in bone tissue engineering, classified them, and discussed their effects on implanted cells and manufacturing techniques. Especially, Polyvinylidene fluoride (PVDF) and its composites are the most practically used piezoelectric biomaterials for bone regeneration. PVDF and its composites have been summarized and discussed to repair damaged bone tissues.

Aloe vera incorporated starch-64S bioactive glass-quail egg shell scaffold for promotion of bone regeneration

Simultaneous promotion of osteoconductive and osteoinductive characteristics through combining bioactive glasses with natural polymers is still a challenge in bone tissue engineering. Starch, 64S bioactive glass (BG), aloe vera (AV) and quail eggshell powder (QE) were utilized to achieve biodegradable, bioactive, biocompatible and mechanically potent multifunctional scaffolds, using freeze-drying mechanism. Cell viability for starch-BG-AV-QE scaffolds at 3 and 7 day intervals was reported to be over 95 %. Acridine orange staining was employed to study live/dead cells cultured on the scaffolds. The high sufficiency of starch-BG-AV-QE scaffolds in osteogenic differentiation and extracellular matrix mineralization was confirmed through alkaline phosphatase activity and alizarin red staining assessments after 7 and 14 days of cell culture. High compressive strength, managed biodegradability and expression of osteocalcin and osteopontin as late markers of osteogenic differentiation were also reached in the range of 30-75 % for starch-BG-AV-QE scaffolds. Hence, starch-BG-AV-QE scaffolds with ideal physico-mechanical and biological characteristics can be considered as promising candidates for promotion of bone regeneration.

Functionalization and Antibacterial Applications of Cellulose-Based Composite Hydrogels

Pathogens, especially drug-resistant pathogens caused by the abuse of antibiotics, have become a major threat to human health and public health safety. The exploitation and application of new antibacterial agents is extremely urgent. As a natural biopolymer, cellulose has recently attracted much attention due to its excellent hydrophilicity, economy, biocompatibility, and biodegradability. In particular, the preparation of cellulose-based hydrogels with excellent structure and properties from cellulose and its derivatives has received increasing attention thanks to the existence of abundant hydrophilic functional groups (such as hydroxyl, carboxy, and aldehyde groups) within cellulose and its derivatives. The cellulose-based hydrogels have broad application prospects in antibacterial-related biomedical fields. The latest advances of preparation and antibacterial application of cellulose-based hydrogels has been reviewed, with a focus on the antibacterial applications of composite hydrogels formed from cellulose and metal nanoparticles; metal oxide nanoparticles; antibiotics; polymers; and plant extracts. In addition, the antibacterial mechanism and antibacterial characteristics of different cellulose-based antibacterial hydrogels were also summarized. Furthermore, the prospects and challenges of cellulose-based antibacterial hydrogels in biomedical applications were also discussed.

Fluorescence-Raman dual-mode quantitative detection and imaging of small-molecule thiols in cell apoptosis with DNA-modified gold nanoflowers

The monitoring of small-molecule thiols (especially glutathione) has attracted widespread attention due to their involvement in numerous physiological processes in living organisms and cells. In this work, a dual-mode nanosensor was designed to detect small-molecule thiols, which is based on the "on-off" switch of fluorescence resonance energy transfer (FRET) and surface-enhanced Raman scattering (SERS). Briefly, DNA was modified by Cy5 (signal probe) and disulfide bonds (recognition element). Gold nanoflowers (AuNFs) were used as the fluorescence-quenching and SERS-enhancing substrate. However, small-molecule thiols can cleave disulfide bonds and release short Cy5-labeled chains, causing the recovery of the fluorescence signal and a decrease of the SERS signal. The nanosensor showed a sensitive response to small-molecule thiols represented by GSH, with a linear range of 0.01-3 mM and a detection limit of 913 nM. In addition, it competed with other related biological interferences and presented good stability and better selectivity towards small-molecule thiols. Most importantly, the developed nanosensor had been successfully applied to in situ imaging and quantitative monitoring of the concentration of small-molecule thiols which changed during T-2 toxin-induced apoptosis in HeLa cells. Meanwhile, nanosensors are also versatile with their potential applications and can be easily extended to the detection and imaging of other human cell lines. The proposed method combines the dual advantages of fluorescence and SERS, which has broad prospects for in situ studies of physiological processes involving small-molecule thiols in biological systems.

Effect of ZnO-doped magnesium phosphate cements on osteogenic differentiation of mBMSCs in vitro

The insufficient osteogenesis of magnesium phosphate cements (MPCs) limits its further application. It is significant to develop a bioactive MPC with osteogenic properties. In this work, MPCs were reinforced by zinc oxide nanoparticles (ZnO-NPs). The composition, microstructure, setting time, compressive strength and degradation of ZnO-NPs/MPCs (ZNMPCs) were evaluated. The results showed that the setting times of MPCs were prolonged from 8.2 to 25.3 min (5.0ZNMPC). The exothermic temperatures were reduced from 45.8 ± 0.4℃ (MPCs) to 39.3 ± 0.5℃ (1.0ZNMPC). The compressive strength of ZNMPC composite cement with 1 wt. % ZnO-NPs (1.0ZNMPC) was the highest (42.9 MPa) among all the composite cements. Furthermore, the ZNMPCs were cultured with mouse bone marrow mesenchymal stem cells (mBMSCs). The results yielded that the ZNMPCs exhibited good cytocompatibility with enhanced differentiation, proliferation, and mineralization on mBMSCs, and it also pronouncedly elevated the expressions of genes and proteins involving osteogenesis. These findings suggested that ZNMPCs could drive the differentiation toward osteogenesis and mineralization of mBMSCs, providing a simple way to the MPC with enhanced osteogenesis for further orthopedic applications.

Preparation of the bioglass/chitosan-alginate composite scaffolds with high bioactivity and mechanical properties as bone graft materials

Bioglass/chitosan-alginate (BCA) composite scaffolds with remarkable performance for bone tissue engineering are successfully prepared by freeze-drying method. The influence of the addition amount of sodium alginate (SA) on the microstructure, porosity, pore size, swelling ratio, degradation ratio, mechanical properties and mineralization ability of BCA composite scaffolds is studied and characterized by various techniques of the scanning electron microscopy, X-ray diffraction, infrared absorption spectrometer and so on. The results show that the BCA composite scaffolds have the three-dimensional interconnected network structure with the high porosity of 82%-87% and a suitable average pore size of 140-200 μm. With the increase of SA addition, the porosity and pore size of BCA gradually reduced and the thickness of pore wall increased. The swelling and degradation ratios decreased gradually with the raising SA and increased with the prolongation of soaking time in PBS. The mechanical strength of BCA was also significantly enhanced, and the mineralization ability of bioglass was effectively deployed with the adding SA of BCA. The improved performance of BCA may be attributed to the formed 3D network structure, activated bioavailability and crosslinking ability between chitosan and SA. It indicates that BCA composite scaffolds have potential applications in bone issues engineering.

Hydroxypropylmethyl cellulose (HPMC) crosslinked keratin/hydroxyapatite (HA) scaffold fabrication, characterization and in vitro biocompatibility assessment as a bone graft for alveolar bone regeneration

Wool derived keratin has garnered significant advancements in the field of biomaterials for hard tissue regeneration. The main limitation of keratin-based biomaterials for bone tissue engineering is their fragile nature. This paper proposes the development of a novel hydroxypropyl methylcellulose (HPMC) crosslinked keratin scaffold, containing hydroxyapatite as a major inorganic component by freeze drying technique for alveolar bone regeneration. The prepared keratin/hydroxyapatite/HPMC (K/HA/HPMC) scaffold was characterized to study its chemical, physical, and mechanical properties by Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDX), X-Ray diffractometric (XRD) analysis. The SEM images of the scaffolds showed highly porous interconnected architecture with average pore size of 108.36 ± 22.56 while microcomputed tomographic analysis measured total porosity as 79.65 %±. Energy dispersive X-ray spectroscopic (EDX) analysis confirmed that inorganic component of scaffold was mainly composed of calcium and phosphorous ions having Ca/P molar ration of 1.6. The maximum compressive strength was found to be in the range of 0.841 ± 0.37 MPa. Furthermore, the K/HA/HPMC scaffold was structurally stable and weight loss of about 26% was observed when soaked in phosphate buffered solution (PBS) for 28 days. In vitro biocompatibility testing showed that K/HA/HPMC scaffold was cytocompatible and supported the attachment, proliferation of osteoblast (Saos-2) cells. Thus, the development of a non-toxic chemical cross-linking system with HPMC was investigated to fabricate K/HA/HPMC scaffold and our results showed great potential of these scaffolds to regenerate alveolar bone due to their structural similarity and excellent in vitro biocompatibility.

Mineralization of phosphorylated cellulose/sodium alginate sponges as biomaterials for bone tissue engineering

The incorporation of SA in the cellulose matrix effectively increased the macroporous ability of composite scaffolds. Furthermore, the phosphorylation has a certain induction capability for the growth of HA.

Biomimetic mineralization of novel hydroxyethyl cellulose/soy protein isolate scaffolds promote bone regeneration in vitro and in vivo

Although various strategies have been utilized to accelerate bone regeneration in bone tissue engineering (BTE), the treatment and repair of large bone defects remains a clinical challenge worldwide. Inspired by the natural extracellular matrix of bone tissue, organic-inorganic composite scaffolds with three-dimensional (3D) porous structures, sufficient mechanical properties, excellent cytocompatibility, osteoconductivity, and osteogenic potential have received considerable attention within the field of bone engineering. In this work, a novel epichlorohydrin (ECH)-crosslinked hydroxyethyl cellulose (HEC)/soy protein isolate (SPI) porous bi-component scaffold (EHSS) with hydroxyapatite (HAp) functionalization (EHSS/HAp) was constructed for bone defect repair via the combination of lyophilization and in situ biomimetic mineralization. Systematic characterization experiments were performed to assess the morphology, HAp-forming properties, mechanical properties and degradation rate of the scaffold. The results indicated that the prepared scaffolds exhibited an interconnected porous structure, a biomimetic HAp coating on their surfaces, improved mechanical properties in compression and a controllable degradation rate. In particular, semiquantitative analysis showed that the calcium/phosphorus (Ca/P) ratio of EHSS/HAp with 70% SPI content (1.65) was similar to that of natural bone tissue (1.67) according to energy dispersive X-ray spectroscopy analysis. In vitro cell culture experiments indicated that the EHSS/HAp with 70% SPI content showed improved cytocompatibility and was suitable for MC3T3-E1 cell attachment, proliferation and growth. Consistently, in vitro osteogenic differentiation studies showed that EHSS/HAp with 70% SPI content can significantly accelerate the expression of osteogenesis-related genes (Col-1, Runx2, OPN, and OCN) during osteogenic differentiation of MC3T3-E1 cells. Furthermore, when applied to the repair of critical-sized cranial defects in a rat model, EHSS/HAp with 70% SPI was capable of significantly promoting tissue regeneration and integration with native bone tissue. Microscopic computed tomography (micro-CT) results demonstrated that the bone defect site was nearly occupied with newly formed bone at 12 weeks after implantation of EHSS/HAp with 70% SPI content into the defect. Hematoxylin and eosin (H&E) staining and Masson's trichrome staining of histological sections further confirmed that EHSS/HAp with 70% SPI markedly promoted new bone formation and maturation. Collectively, our results demonstrate the potential of EHSS/HAp scaffolds with 70% SPI for successful bone defect repair and regeneration.

Preparation of Zn doped mesoporous silica nanoparticles (Zn-MSNs) for the improvement of mechanical and antibacterial properties of dental resin composites

OBJECTIVE

The purpose of this work was to explore the enhancement effect of zinc doped mesoporous silica nanoparticles (Zn-MSNs), which could form micromechanical interlocking with resin matrix and sustainably release Zn²⁺, on the mechanical and antibacterial properties of the dental resin composites.

METHODS

Zn-MSNs were prepared by a sol-gel method, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N₂ adsorption/desorption. The mechanical properties of the dental composites reinforced by Zn-MSNs were measured by a universal mechanical testing machine. Antibacterial activities of dental composites were evaluated by both qualitative and quantitative analysis using Streptococcus mutans (S. mutans). The cytotoxicity of the Zn-MSNs filled dental composites was investigated by osteoblasts (OBs).

RESULTS

The synthesized Zn-MSNs possessed good monodispersity with an average particle size of about 138nm. The mechanical properties of the composites gradually increased with the increase of the content of Zn-MSNs. The flexural strength, flexural modulus, compressive strength and micro-hardness of the composites containing 15wt% Zn-MSNs were 31.21%, 50.47%, 53.83% and 26.79% higher than the samples with no Zn-MSNs, respectively. The antibacterial performance was significantly improved by the addition of Zn-MSNs and the antibacterial rate of the composite with 15wt% of Zn-MSNs reached 100%. Cytotoxicity tests revealed that all the composites were biocompatible during OBs incubation.

SIGNIFICANCE

The prepared Zn-MSNs can effectively improve the mechanical and antibacterial properties of the dental resin composites.

Bioactive polymeric scaffolds for osteogenic repair and bone regenerative medicine

The loss of bone tissue is a striking challenge in orthopedic surgery. Tissue engineering using various advanced biofunctional materials is considered a promising approach for the regeneration and substitution of impaired bone tissues. Recently, polymeric supportive scaffolds and biomaterials have been used to rationally promote the generation of new bone tissues. To restore the bone tissue in this context, biofunctional polymeric materials with significant mechanical robustness together with embedded materials can act as a supportive matrix for cellular proliferation, adhesion, and osteogenic differentiation. The osteogenic regeneration to replace defective tissues demands greater calcium deposits, high alkaline phosphatase activity, and profound upregulation of osteocalcin as a late osteogenic marker. Ideally, the bioactive polymeric scaffolds (BPSs) utilized for bone tissue engineering should impose no detrimental impacts and function as a carrier for the controlled delivery and release of the loaded molecules necessary for the bone tissue regeneration. In this review, we provide comprehensive insights into different synthetic and natural polymers used for the regeneration of bone tissue and discuss various technologies applied for the engineering of BPSs and their physicomechanical properties and biological effects.

Generation of scaffold incorporated with nanobioglass encapsulated in chitosan/chondroitin sulfate complex for bone tissue engineering

Over the past decade, various composite materials fabricated using natural or synthetic biopolymers incorporated with bioceramic have been widely investigated for the regeneration of segmental bone defect. In the present study, nano-bioglass incorporated osteoconductive composite scaffolds were fabricated through polyelectrolyte complexation/phase separation and resuspension of separated complex in gelatin matrix. Developed scaffold exhibits controlled bioreactivity, minimize abrupt pH rise (~7.8), optimal swelling behavior (2.6+-3.1) and enhances mechanical strength (0.62 ± 0.18 MPa) under wet condition. Moreover, in-vitro cell study shows that the fabricated scaffold provide suitable template for cellular attachment, spreading, biomineralization and collagen based matrix deposition. Also, the developed scaffold was evaluated for biocompatibility and bone tissue regeneration potential through implantation in non-union segmental bone defect created in rabbit animal model. The obtained histological analysis indicates strong potential of the composite scaffold for bone tissue regeneration, vascularization and reconstruction of defects. Thus, the developed composite scaffold might be a suitable biomaterial for bone tissue engineering applications.

Glycaemic control in diabetic rats treated with islet transplantation using plasma combined with hydroxypropylmethyl cellulose hydrogel

Islet transplantation is one of the most efficient cell therapies used in clinics and could treat a large proportion of patients with diabetes. However, it is limited by the high requirement of pancreas necessary to provide the sufficient surviving islet mass in the hepatic tissue and restore normoglycaemia. Reduction in organ procurement requirements could be achieved by extrahepatic transplantation using a biomaterial that enhances islet survival and function. We report a plasma-supplemented hydroxypropyl methylcellulose (HPMC) hydrogel, engineered specifically using a newly developed technique for intra-omental islet infusion, known as hOMING (h-Omental Matrix Islet filliNG). The HPMC hydrogel delivered islets with better performance than that of the classical intrahepatic infusion. After the validation of the HPMC suitability for islets in vivo and in vitro, plasma supplementation modified the rheological properties of HPMC without affecting its applicability with hOMING. The biomaterial association was proven to be more efficient both in vitro and in vivo, with better islet viability and function than that of the current clinical intrahepatic delivery technique. Indeed, when the islet mass was decreased by 25% or 35%, glycaemia control was observed in the group of plasma-supplemented hydrogels, whereas no regulation was observed in the hepatic group. Plasma gelation, observed immediately post infusion, decreased anoïkis and promoted vascularisation. To conclude, the threshold mass for islet transplantation could be decreased using HPMC-Plasma combined with the hOMING technique. The simplicity of the hOMING technique and the already validated use of its components could facilitate its transfer to clinics. STATEMENT OF SIGNIFICANCE: One of the major limitations for the broad deployment of current cell therapy for brittle type 1 diabetes is the islets' destruction during the transplantation process. Retrieved from their natural environment, the islets are grafted into a foreign tissue, which triggers massive cell loss. It is mandatory to provide the islets with an 3D environment specifically designed for promoting isletimplantation to improve cell therapy outcomes. For this aim, we combined HPMC and plasma. HPMC provides suitable rheological properties to the plasma to be injectable and be maintained in the omentum. Afterwards, the plasma polymerises around the graft in vivo, thereby allowing their optimal integration into their transplantation site. As a result, the islet mass required to obtain glycaemic control was reduced by 35%.

Nano- and Micropatterned Polycaprolactone Cellulose Composite Surfaces with Tunable Protein Adsorption, Fibrin Clot Formation, and Endothelial Cellular Response

This work describes the interaction of the human blood plasma proteins albumin, fibrinogen, and γ-globulins with micro- and nanopatterned polymer interfaces. Protein adsorption studies were correlated with the fibrin clotting time of human blood plasma and with the growth of primary human pulmonary artery endothelial cells (hECs) on these patterns. It was observed that blends of polycaprolactone (PCL) and trimethylsilyl-protected cellulose form various thin-film patterns during spin coating, depending on the mass ratio of the polymers in the spinning solutions. Vapor-phase acid-catalyzed deprotection preserves these patterns but yields interfaces that are composed of hydrophilic cellulose domains enclosed by hydrophobic PCL. The blood plasma proteins are repelled by the cellulose domains, allowing for a suggested selective protein deposition on the PCL domains. An inverse proportional correlation is observed between the amount of cellulose present in the films and the mass of irreversibly adsorbed proteins. This results in significantly increased fibrin clotting times and lower masses of deposited clots on cellulose-containing films as revealed by quartz crystal microbalance with dissipation measurements. Cell viability of hECs grown on these surfaces was directly correlated with higher protein adsorption and faster clot formation. The results show that presented patterned polymer composite surfaces allow for a controllable blood plasma protein coagulation and a significant biological response from hECs. It is proposed that this knowledge can be utilized in regenerative medicine, cell cultures, and artificial vascular grafts by a careful choice of polymers and patterns.

Chitosan capped copper oxide/copper nanoparticles encapsulated microbial resistant nanocomposite films

Chitosan (CH) capped inorganic nanomaterials have been considered as significant antibacterial materials in the clinical field. This work shows the synthesis of two new different antibacterial composite films as a result of the incorporation of CH capped copper oxide (CHCuO) and copper (CHCu) nanoparticles (NPs). Here, CHCuO and CHCu NPs were achieved by a facile chemical reduction of Cu²⁺ ions using sodium hydroxide and ascorbic acid. TEM analysis revealed the morphology as rod-type nanoflakes for CHCuO and a spherical shape for CHCu NPs with ~7 ± 2 nm size. Antimicrobial activity of the developed materials was studied by the inhibition zone method, against both gram-negative and gram-positive bacteria. The antimicrobial activity revealed that the CHCuO NPs and CHCuO-CH film showed a higher inhibition zone than the other nanomaterials. The results suggested that the synthesized materials can be used in wound dressing applications.

Emulsion Template Method for the Fabrication of Gelatin-Based Scaffold with a Controllable Pore Structure

The porous microstructure of scaffolds is an essential consideration for tissue engineering, which plays an important role for cell adhesion, migration, and proliferation. It is crucial to choose optimum pore sizes of scaffolds for the treatment of various damaged tissues. Therefore, the proper porosity is the significant factor that should be considered when designing tissue scaffolds. Herein, we develop an improved emulsion template method to fabricate gelatin-based scaffolds with controllable pore structure. Gelatin droplets were first prepared by emulsification and then solidified by genipin to prepare gelatin microspheres. The microspheres were used as a template for the fabrication of porous scaffolds, which were gathered and tightened together by dialdehyde amylose. The results showed that emulsification can produce gelatin microspheres with narrow size distribution. The size of gelatin microspheres was easily controlled by adjusting the concentration of gelatin and the speed of mechanical agitation. The gelatin-based scaffolds presented macroporous and interconnected structure. It is interesting that the pore size of scaffolds was directly related to the size of gelatin microspheres, displaying the same trend of change in size. It indicated that the gelatin microspheres can be used as the proper template to fabricate gelatin-based scaffold with a desired pore structure. In addition, the gelatin-based scaffolds possessed good blood compatibility and cytocompatibility. Overall, the gelatin-based scaffolds exhibited great potential in tissue engineering.