Bioactive glass based scaffolds coated with gelatin for the sustained release of icariin

Promoting osteogenesis and bone regeneration employing icariin-loaded nanoplatforms

There is an increasing demand for innovative strategies that effectively promote osteogenesis and enhance bone regeneration. The critical process of bone regeneration involves the transformation of mesenchymal stromal cells into osteoblasts and the subsequent mineralization of the extracellular matrix, making up the complex mechanism of osteogenesis. Icariin's diverse pharmacological properties, such as anti-inflammatory, anti-oxidant, and osteogenic effects, have attracted considerable attention in biomedical research. Icariin, known for its ability to stimulate bone formation, has been found to encourage the transformation of mesenchymal stromal cells into osteoblasts and improve the subsequent process of mineralization. Several studies have demonstrated the osteogenic effects of icariin, which can be attributed to its hormone-like function. It has been found to induce the expression of BMP-2 and BMP-4 mRNAs in osteoblasts and significantly upregulate Osx at low doses. Additionally, icariin promotes bone formation by stimulating the expression of pre-osteoblastic genes like Osx, RUNX2, and collagen type I. However, icariin needs to be effectively delivered to bone to perform such promising functions.Encapsulating icariin within nanoplatforms holds significant promise for promoting osteogenesis and bone regeneration through a range of intricate biological effects. When encapsulated in nanofibers or nanoparticles, icariin exerts its effects directly at the cellular level. Recalling that inflammation is a critical factor influencing bone regeneration, icariin's anti-inflammatory effects can be harnessed and amplified when encapsulated in nanoplatforms. Also, while cell adhesion and cell migration are pivotal stages of tissue regeneration, icariin-loaded nanoplatforms contribute to these processes by providing a supportive matrix for cellular attachment and movement. This review comprehensively discusses icariin-loaded nanoplatforms used for bone regeneration and osteogenesis, further presenting where the field needs to go before icariin can be used clinically.

Developing Chinese herbal-based functional biomaterials for tissue engineering

The role of traditional Chinese medicine (TCM) in treating diseases is receiving increasing attention. Chinese herbal medicine is an important part of TCM with various applications and the active ingredients extracted from Chinese herbal medicines have physiological and pathological effects. Tissue engineering combines cell biology and materials science to construct tissues or organs in vitro or in vivo. TCM has been proposed by the World Health Organization as an effective treatment modality. In recent years, the potential use of TCM in tissue engineering has been demonstrated. In this review, the classification and efficacy of TCM active ingredients and delivery systems are discussed based on the TCM theory. We also summarized the current application status and broad prospects of Chinese herbal active ingredients in different specialized biomaterials in the field of tissue engineering. This review provides novel insights into the integration of TCM and modern Western medicine through the application of Chinese medicine in tissue engineering and regenerative medicine.

Polymeric and Composite Carriers of Protein and Non-Protein Biomolecules for Application in Bone Tissue Engineering

Conventional intake of drugs and active substances is most often based on oral intake of an appropriate dose to achieve the desired effect in the affected area or source of pain. In this case, controlling their distribution in the body is difficult, as the substance also reaches other tissues. This phenomenon results in the occurrence of side effects and the need to increase the concentration of the therapeutic substance to ensure it has the desired effect. The scientific field of tissue engineering proposes a solution to this problem, which creates the possibility of designing intelligent systems for delivering active substances precisely to the site of disease conversion. The following review discusses significant current research strategies as well as examples of polymeric and composite carriers for protein and non-protein biomolecules designed for bone tissue regeneration.

Highly porous bio-glass scaffolds fabricated by polyurethane template method with hydrothermal treatment for tissue engineering uses

Objectives

Bioglass scaffolds, which contain a significant percentage of porosity for tissue engineering purposes, have low strength. For increasing the strength and efficiency of such structures for use in tissue engineering, fabrication of hierarchical meso/macro-porous bioglass scaffolds, developing their mechanical strength by hydrothermal treatment and adjusting pH method, and achieving the appropriate mesopore size for loading large biomolecules, were considered in this study.

Materials and Methods

Mesoporous bioglass (MBG) powders were synthesized using cetyltrimethylammonium bromide as a surfactant, with different amounts of calcium sources to obtain the appropriate size of the mesoporous scaffolds. Then MBG scaffolds were fabricated by a polyurethane foam templating method, and for increasing scaffold strength hydrothermal treatment (90 ^°C, for 5 days) and adjustment pH (pH=9) method was used to obtain hierarchical meso/macro-porous structures. The sample characterization was done by Simultaneous thermal analysis, Fourier transform infrared spectroscopy, Field Emission Scanning electron microscopy, small and wide-angle X-ray powder diffractions, transmission electron microscopy, and analysis of nitrogen adsorption-desorption isotherm. The mechanical strength of scaffolds was also determined.

Results

The MBG scaffolds based on 80.28 (wt.) % SiO₂- 17.89 (wt.) % CaO- 1.81 (wt.) % P₂O₅ presented interconnected large pores and pores in the range of 100-150 μm and 6-18 nm, respectively and 0.4 MPa compressive strength.

Conclusion

The total pore volume and specific surface area were obtained from the Brunauer-Emmett-Teller theory, 0.709 cm³ g^-1 and 213.83 m² g^-1, respectively. These findings could be considered in bone-cartilage tissue engineering.

Progress in Composite Hydrogels and Scaffolds Enriched with Icariin for Osteochondral Defect Healing

Osteochondral structure reconstruction by tissue engineering, a challenge in regenerative medicine, requires a scaffold that ensures both articular cartilage and subchondral bone remodeling. Functional hydrogels and scaffolds present a strategy for the controlled delivery of signaling molecules (growth factors and therapeutic drugs) and are considered a promising therapeutic approach. Icariin is a pharmacologically-active small molecule of prenylated flavonol glycoside and the main bioactive flavonoid isolated from Epimedium spp. The in vitro and in vivo testing of icariin showed chondrogenic and ostseoinductive effects, comparable to bone morphogenetic proteins, and suggested its use as an alternative to growth factors, representing a low-cost, promising approach for osteochondral regeneration. This paper reviews the complex structure of the osteochondral tissue, underlining the main aspects of osteochondral defects and those specifically occurring in osteoarthritis. The significance of icariin’s structure and the extraction methods were emphasized. Studies revealing the valuable chondrogenic and osteogenic effects of icariin for osteochondral restoration were also reviewed. The review highlighted th recent state-of-the-art related to hydrogels and scaffolds enriched with icariin developed as biocompatible materials for osteochondral regeneration strategies.

Traditional Chinese Medicine Compound-Loaded Materials in Bone Regeneration

Bone is a dynamic organ that has the ability to repair minor injuries via regeneration. However, large bone defects with limited regeneration are debilitating conditions in patients and cause a substantial clinical burden. Bone tissue engineering (BTE) is an alternative method that mainly involves three factors: scaffolds, biologically active factors, and cells with osteogenic potential. However, active factors such as bone morphogenetic protein-2 (BMP-2) are costly and show an unstable release. Previous studies have shown that compounds of traditional Chinese medicines (TCMs) can effectively promote regeneration of bone defects when administered locally and systemically. However, due to the low bioavailability of these compounds, many recent studies have combined TCM compounds with materials to enhance drug bioavailability and bone regeneration. Hence, the article comprehensively reviewed the local application of TCM compounds to the materials in the bone regeneration in vitro and in vivo. The compounds included icariin, naringin, quercetin, curcumin, berberine, resveratrol, ginsenosides, and salvianolic acids. These findings will contribute to the potential use of TCM compound-loaded materials in BTE.

Advanced approaches for improving bioavailability and controlled release of anthocyanins

Anthocyanins are a group of phytochemicals responsible for the purple or red color of plants. Additionally, they are recognized to have health promoting functions including anti-cardiovascular, anti-thrombotic, anti-diabetic, antimicrobial, neuroprotective, and visual protective effect as well as anti-cancer activities. Thus, consumption of anthocyanin supplement or anthocyanin-rich foods has been recommended to prevent the risk of development of chronic diseases. However, the low stability and bioavailability of anthocyanins limit the efficacy and distribution of anthocyanins in human body. Thus, strategies to achieve target site-local delivery with good bioavailability and controlled release rate are necessary. This review introduced and discussed the latest advanced techniques of designing lipid-based, polysaccharide-based and protein-based complexes, nano-encapsulation and exosome to overcome the limitation of anthocyanins. The improved bioavailability and controlled release of anthocyanins have great significance for gastrointestinal tract absorption, transepithelial transportation and cellular uptake. The techniques of applying different biocompatible materials and modifying the solubility of anthocyanins complex could achieve target site-local delivery with negligible degradation and good bioavailability in human body.

Antibacterial and antioxidant activity of cinnamon essential oil-laden 45S5 bioactive glass/soy protein composite scaffolds for the treatment of bone infections and oxidative stress

This study aimed to fabricate cinnamon essential oil (CO)-laden 45S5 bioactive glass (BG)/soy protein (SP) scaffolds exhibiting antioxidant and antibacterial activity. In this regard, 45S5 BG-based scaffolds were produced by the foam replica method, and subsequently the scaffolds were coated with various concentrations of CO (2.5, 5 and 7 (v/v) %) incorporated SP solution. Scanning electron microscopy images revealed that the CO-laden SP effectively attached to the 45S5 BG scaffold struts. The presence of 45S5 BG, SP and CO was confirmed using Fourier transform infrared spectroscopy. Compressive strength results indicated that SP based coatings improved the scaffolds' mechanical properties compared to uncoated BG scaffolds. The loading efficiency and releasing behaviour of the different CO concentrations were tested by gas chromatography-mass spectroscopy and UV-Vis spectroscopy. The results showed that CO incorporated scaffolds have controlled releasing behaviour over seven days. Furthermore, the coating on the scaffold surfaces slightly retarded, but it did not inhibit, the in vitro bioactivity of the scaffolds. Moreover, the antioxidant and antibacterial activity of CO was studied. The free radical scavenging activity measured by DPPH was 5 ± 1, 41 ± 3, 44 ± 1 and 43 ± 1 % for BGSP, CO2.5, CO5 and CO7, respectively. The antioxidant activity was thus enhanced by incorporating CO. Agar diffusion and colony counting results indicated that the incorporation of CO increased the antibacterial activity of scaffolds against S. aureus and E. coli. In addition, cytotoxicity of the scaffolds was investigated using MG-63 osteoblast-like cells. The results showed that the BG-SP scaffold was non-toxic under the investigated conditions, whereas dose-dependent toxicity was observed in CO-laden scaffolds. Considered together, the developed phytotherapeutic agent laden 45S5 BG-based scaffolds are promising for bone tissue engineering exhibiting capability to combat bone infections and to protect against oxidative stress damage.

Biomimetic Calcium Phosphate Coatings for Bioactivation of Titanium Implant Surfaces: Methodological Approach and In Vitro Evaluation of Biocompatibility

Ti6Al4V as a common implant material features good mechanical properties and corrosion resistance. However, untreated, it lacks bioactivity. In contrast, coatings with calcium phosphates (CaP) were shown to improve cell-material interactions in bone tissue engineering. Therefore, this work aimed to investigate how to tailor biomimetic CaP coatings on Ti6Al4V substrates using modified biomimetic calcium phosphate (BCP) coating solutions. Furthermore, the impact of substrate immersion in a 1 M alkaline CaCl2 solution (pH = 10) on subsequent CaP coating formation was examined. CaP coatings were characterized via scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray spectroscopy, and laser-scanning microscope. Biocompatibility of coatings was carried out with primary human osteoblasts analyzing cell morphology, proliferation, collagen type 1, and interleukin 6 and 8 release. Results indicate a successful formation of low crystalline hydroxyapatite (HA) on top of every sample after immersion in each BCP coating solution after 14 days. Furthermore, HA coating promoted cell proliferation and reduced the concentration of interleukins compared to the uncoated surface, assuming increased biocompatibility.

Bioactive glass: A multifunctional delivery system

Bioactive glasses (BAGs) were invented five decades ago and have been widely used clinically in orthopedic and stomatology. However, in the past two decades, BAGs have been explored immensely by several researchers worldwide as a multifunctional delivery system for a multitude of therapeutics ranging from metal ions to small molecules (e.g., drugs) and macromolecules (e.g., DNA). The impetus for devising a BAG-based delivery system in the 21st century is based upon the facilitative properties it offers for entrapment of a wide range of therapeutic molecules and the tailorable controlled release kinetics to the target tissue site along with the biological activity of the ionic dissolution products in several pathological conditions such as osteoporosis, cancer, infection, and inflammation. This review comprises two parts: the first part discusses the need for a new delivery system and how the journey from melt quench progressed towards template-based sol-gel mesoporous. In the second part, we have comprehended the scientific advancements made so far, emphasizing BAGs as a delivery system ranging from therapeutic ions to phytopharmaceuticals. We have also highlighted a few loopholes that have prevented bench-to-bedside clinical translation of a plethora of elucidative researches done so far.

Architecture-Promoted Biomechanical Performance-Tuning of Tissue-Engineered Constructs for Biological Intervertebral Disc Replacement

Background: Biological approaches to intervertebral disc (IVD) restoration and/or regeneration have become of increasing interest. However, the IVD comprises a viscoelastic system whose biological replacement remains challenging. The present study sought to design load-sharing two-component model systems of circular, nested, concentric elements reflecting the nucleus pulposus and annulus fibrosus. Specifically, we wanted to investigate the effect of architectural design variations on (1) model system failure loads when testing the individual materials either separately or homogeneously mixed, and (2) also evaluate the potential of modulating other mechanical properties of the model systems. Methods: Two sets of softer and harder biomaterials, 0.5% and 5% agarose vs. 0.5% agarose and gelatin, were used for fabrication. Architectural design variations were realized by varying ring geometries and amounts while keeping the material composition across designs comparable. Results: Variations in the architectural design, such as lamellar width, number, and order, combined with choosing specific biomaterial properties, strongly influenced the biomechanical performance of IVD constructs. Biomechanical characterization revealed that the single most important parameter, in which the model systems vastly exceeded those of the individual materials, was failure load. The model system failure loads were 32.21- and 84.11-fold higher than those of the agarose materials and 55.03- and 2.14-fold higher than those of the agarose and gelatin materials used for system fabrication. The compressive strength, dynamic stiffness, and viscoelasticity of the model systems were always in the range of the individual materials. Conclusions: Relevant architecture-promoted biomechanical performance-tuning of tissue-engineered constructs for biological IVD replacement can be realized by slight modifications in the design of constructs while preserving the materials’ compositions. Minimal variations in the architectural design can be used to precisely control structure–function relations for IVD constructs rather than choosing different materials. These fundamental findings have important implications for efficient tissue-engineering of IVDs and other load-bearing tissues, as potential implants need to withstand high in situ loads.

Recent developments in sustainably sourced protein-based biomaterials

Research into the development of sustainable biomaterials is increasing in both interest and global importance due to the increasing demand for materials with decreased environmental impact. This research field utilises natural, renewable resources to develop innovative biomaterials. The development of sustainable biomaterials encompasses the entire material life cycle, from desirable traits, and environmental impact from production through to recycling or disposal. The main objective of this review is to provide a comprehensive definition of sustainable biomaterials and to give an overview of the use of natural proteins in biomaterial development. Proteins such as collagen, gelatin, keratin, and silk, are biocompatible, biodegradable, and may form materials with varying properties. Proteins, therefore, provide an intriguing source of biomaterials for numerous applications, including additive manufacturing, nanotechnology, and tissue engineering. We give an insight into current research and future directions in each of these areas, to expand knowledge on the capabilities of sustainably sourced proteins as advanced biomaterials.

Production of Soda Lime Glass Having Antibacterial Property for Industrial Applications

This study was aimed to produce and characterize the first commercial glass materials with enhanced antibacterial property using conventional melting method. For this purpose, typical container glass composition that contains some specific metal ions, such as silver, strontium, and copper, was used to obtain antibacterial glass samples using classical melting method. After the melting process, antibacterial tests and migration tests were applied to the glasses, and it was found that the glass doped with 2% Ag₂O was the best composition. X-rays diffractometer (XRD), thermal expansion coefficient, density, refractive index, hardness, and elastic module results showed that the glass doped with 2% Ag₂O was a suitable material as a container glass. High Temperature Melting Observation System studies were performed on the produced antibacterial glass composition, and it was found that the antibacterial glass can be produced in soda lime glass furnaces without changing any furnace design and production parameters. As a result of the characterization studies, it was concluded that the produced container glass doped with silver can be a good candidate for food and pharmaceutical products where bacterial growth is absolutely undesirable.

Spatial Presentation of Tissue-Specific Extracellular Matrix Components along Electrospun Scaffolds for Tissue Engineering the Bone-Ligament Interface

The bone-ligament interface transitions from a highly organized type I collagen rich matrix to a nonmineralized fibrocartilage region and finally to a mineralized fibrocartilage region that interfaces with the bone. Therefore, engineering the bone-ligament interface requires a biomaterial substrate capable of maintaining or directing the spatially defined differentiation of multiple cell phenotypes. To date the appropriate combination of biophysical and biochemical factors that can be used to engineer such a biomaterial substrate remain unknown. Here we show that microfiber scaffolds functionalized with tissue-specific extracellular matrix (ECM) components can direct the differentiation of MSCs toward the phenotypes seen at the bone-ligament interface. Ligament-ECM (L-ECM) promoted the expression of the ligament-marker gene tenomodulin (TNMD) and higher levels of type I and III collagen expression compared to functionalization with commercially available type I collagen. Functionalization of microfiber scaffolds with cartilage-ECM (C-ECM) promoted chondrogenesis of MSCs, as evidenced by adoption of a round cell morphology and increased SRY-box 9 (SOX9) expression in the absence of exogenous growth factors. Next, we fabricated a multiphasic scaffold by controlling the spatial presentation of L-ECM and C-ECM along the length of a single electrospun microfiber construct, with the distal region of the C-ECM coated fibers additionally functionalized with an apatite layer (using simulated body fluid) to promote endochondral ossification. These ECM functionalized scaffolds promoted spatially defined differentiation of MSCs, with higher expression of TNMD observed in the region functionalized with L-ECM, and higher expression of type X collagen and osteopontin (markers of endochondral ossification) observed at the end of the scaffold functionalized with C-ECM and the apatite coating. Our results demonstrate the utility of tissue-specific ECM derived components as a cue for directing MSC differentiation when engineering complex multiphasic interfaces such as the bone-ligament enthesis.

Tanshinone IIA Delivery Silk Fibroin Scaffolds Significantly Enhance Articular Cartilage Defect Repairing via Promoting Cartilage Regeneration

Cartilage tissue engineering is a promising approach for repairing articular cartilage defects and requires proper scaffolds and necessary growth factors. Herein, tanshinone IIA (TAN) delivery silk fibroin scaffolds were prepared for efficient cartilage defect repair by bioactivities of TAN. By incubating with the TAN delivery silk fibroin scaffold, the transcription of the chondrocytic activity-related genes was enhanced in chondrocytes, and it also can inhibit cell apoptosis and reduce the oxidative stress by regulating the transcription of related genes, indicating that these scaffolds may promote cartilage regeneration. TAN10 delivery silk fibroin scaffolds, in which the concentration of TAN is 10 μg/mL, significantly promotes chondrocytes to generate the cartilage-specific extracellular matrix and tissue both in vitro and in vivo, compared with silk fibroin scaffolds. By treating rabbit articular cartilage defects with TAN10 delivery silk fibroin scaffolds, cartilage defects were filled with hyaline-cartilage-like tissue that integrated with the surrounding cartilage perfectly and displayed strong mechanical properties and higher extracellular matrix content. Hence, TAN facilitates cartilage regeneration, and TAN delivery silk fibroin scaffolds can be potentially applied in the clinics treating cartilage defects in the future.

Macroporous scaffolds developed from CaSiO3 nanofibers regulating bone regeneration via controlled calcination

Calcium silicate (CS) is envisioned as a good substrate for bone tissue engineering applications because it can provide bioactive ions like Ca²⁺ and Si⁴⁺ to promote bone regeneration. Calcination temperature is a critical factor in determining the crystallinity of CS ceramic, which subsequently influences its degradation and ion release behaviors. To investigate the effect of calcination temperature on the capacity of CS in inducing bone regeneration, CS nanofibers were fabricated via electrospinning of precursor sol-gel and subsequent sintering at 800 °C, 1000 °C or 1200 °C. As the calcination temperature was increased, the obtained CS nanofibers displayed higher crystallinity and slower degradation rate. The CS nanofibers calcined at 800 °C (800 m) would like to cause high pH (>9) in cell culture medium due to its rapid ion release rate, displaying adverse effect on cell viability. Among all the preparations, it was found the CS nanofibers calcined at 1000 °C (1000 m) demonstrated the strongest promotion effect on the osteogenic differentiation of bone marrow mesenchymal stromal cells. To facilitate in vivo implantation, the CS nanofibers were shaped into three-dimensional macroporous scaffolds and coated with gelatin to improve their mechanical stability. By implanting the scaffolds into rat calvarial defects, it was confirmed the scaffold made of CS nanofibers calcined at 1000 °C was able to enhance new bone formation more efficiently than the scaffolds made of CS nanofibers calcined at 800 °C or 1200 °C. To summarize, calcination temperature could be an effective and useful tool applied to produce CS bioceramic substrates with improved potential in enhancing osteogenesis by regulating their degradation and bioactive ion release behaviors.

Icariin controlled release on a silk fibroin/mesoporous bioactive glass nanoparticles scaffold for promoting stem cell osteogenic differentiation

The treatment of bone defects caused by various reasons is still a major problem in orthopedic clinical work. Many studies on osteogenic implant materials have used various biologically active factors such as osteogenic inducers, but these biologically active factors have various side effects. Therefore, in this study, silk fibroin (SF) was used as a scaffold material, mesoporous bioactive glass nanoparticles (MBGNs) as a sustained release carrier, and the traditional Chinese drug icariin (ICA) was loaded to promote bone formation. The experiments in this study have proven that SF/MBGNs-ICA scaffolds can successfully load and release ICA for a long time, and the sustained-release ICA can promote the proliferation and differentiation of BMSCs for a long time. This controlled-release ICA organic/inorganic two-component scaffold material is expected to become a new bone grafting solution.

Fabrication of chitosan-coated porous polycaprolactone/strontium-substituted bioactive glass nanocomposite scaffold for bone tissue engineering

In the present study, porous (about 70 vol%) nanocomposite scaffolds made of polycaprolactone (PCL) and different amounts (0 to 15 wt%) of 45S bioactive glass (BG) nanoparticles (with a particle size of about 40 nm) containing 7 wt% strontium (Sr) were fabricated by solvent casting technique for bone tissue engineering. Then, a selected optimum scaffold was coated with a thin layer of chitosan containing 15 wt% Sr-substituted BG nanoparticles. Several techniques such as X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), tensile test, and water contact angle measurement were used to characterize the fabricated samples. In vitro experiments including degradation, bioactivity, and biocompatibility (i.e., cytotoxicity, alkaline phosphate activity, and cell adhesion) tests of the fabricated scaffold were performed. The biomedical behavior of the fabricated PCL-based composite scaffold was interpreted by considering the presence of the porosity, Sr-substituted BG nanoparticles, and the chitosan coating. In conclusion, the fabricated chitosan-coated porous PCL/BG nanocomposite containing 15 wt% BG nanoparticles could be utilized as a good candidate for bone tissue engineering.

Icariin-Functionalized Coating on TiO2 Nanotubes Surface to Improve Osteoblast Activity In Vitro and Osteogenesis Ability In Vivo

Surface modification of titanium is encouraged to facilitate early osseointegration in dental and orthopedic fields. Icariin is the main active constituents of Herba Epimedii, which has good bone-promoting ability. We established an icariin-functionalized coating composed of icariin and poly (lactic-co-glycolic acid) (PLGA) on TiO2 nanotubes surface (NT-ICA-PLGA) to promote osteoblast cell activity and early osseointegration. Surface topography, wettability and drug release pattern of the established NT-ICA-PLGA surface were characterized by scanning electron microscopy (SEM), contact angle test and drug release test. MC3T3-E1 osteoblast cell activity tests were performed using SEM, immunofluorescent staining, cell counting kit-8 and alkaline phosphatase assays. The osteogenic effects of different surfaces were observed using a rat model. Surface characterization proved the successful fabrication of the icariin-functionalized coating on the TiO2 nanotube structure, with increased wettability. The NT-ICA-PLGA substrate showed sustained release of icariin until two weeks. Osteoblast cells grown on the NT-ICA-PLGA substrate displayed improved cell adhesion, proliferation and differentiation ability than the control Ti surface. The in vivo experiment also revealed superior bone forming ability on the NT-ICA-PLGA surface, compared to the pure Ti control. These results imply that the developed NT-ICA-PLGA substrate has a promising future use as functionalized coating for implant surface modification.

Preparation and characterization of general-purpose gelatin-based co-loading flavonoids nano-core structure

Flavonoids (FLAs) possess anti-cancer, anti-viral, anti-bacterial, and anti-oxidant properties. In this study, gelatin nanoparticles (GNPs) with controllable surface potential and diameter was prepared through a modified two-step desolvation. Two well-known flavonoids, namely, low-molecular weight Genistein (GEN) and high-molecular weight Icariin (ICA), were adsorbed onto the surface of GNPs (FLA@GNPs). The characteristics of GNPs and the main parameters affecting flavonoid adsorption were studied to evaluate the adsorption capacity and structural stability of FLA@GNPs. Furthermore, co-adsorption of GEN and ICA was detected. The adsorption mechanism of GNPs with FLA was further discussed. Results showed that the low-molecular weight GEN could be effectively adsorbed by GNPs, and their entrapment efficiencies were over 90% under optimized conditions. The total drug loading of the co-adsorbed FLA@GNPs was significantly higher than that of the single drug loaded (GEN or ICA). GEN@GNPs could maintain its structural stability under acidic conditions (pH = 2) at room temperature (25 °C). This protective function enables both ICA and GEN to be bioactive at room temperature for at least 180 days. The characteristics of GNPs adsorption indicate that the hydrogen bonding theory of the combination of gelatin molecules with polyphenols cannot sufficiently explain the binding of GNPs with polyphenols. FLA@GNPs is a promising general-purpose gelatin-based co-loading preload structure with simplified operation and storage condition.