Layer-by-Layer Deposition of Hyaluronan and Quercetin-Loaded Chitosan Nanoparticles onto Titanium for Improving Blood Compatibility

Quercetin and 5-Fu Loaded Chitosan Nanoparticles Trigger Cell-Cycle Arrest and Induce Apoptosis in HCT116 Cells via Modulation of the p53/p21 Axis

Nanoparticles (NPs) are encapsulating agents that exist in the nanometer range. They can be classified into different classes based on their properties, shapes, or sizes. Metal NPs, fullerenes, polymeric NPs, ceramic NPs, and luminescent nanoporous hybrid materials are only a few examples. This study explored the anticancer potential of quercetin and 5-fluorouracil-encapsulated chitosan nanoparticles (CS-5-FU-QCT NPs). The nanoparticles were prepared by ionic gelation, and their efficacy and mechanism of action were examined. CS-5-FU-QCT NPs were characterized using dynamic light scattering (DLS), atomic force microscopy (AFM), UV-visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR); cytotoxicity was analyzed using an MTT assay. Cells were treated with CS-5-FU-QCT NPs and incubated for 12, 24, and 36 h, and apoptosis analysis (using Annexin V/FITC), cell-cycle analysis, Western blotting, and confocal microscopic analysis were performed. Biophysical analysis revealed that the CS-5-FU-QCT NPs fall in the range of 300-400 nm with a near-spherical shape. The in vitro drug release profile indicates sustained release of drugs over a period of about 36 h. The cytotoxicity of CS-5-FU-QCT NPs was more prominent in HCT116 cells than in other cancer cells. This particular nanoformulation caused G0/G1 phase cell-cycle arrest in HCT116 cells and induced intracellular ROS generation, thereby causing apoptosis. It also downregulated Bcl2, cyclin D1, and Cdk4 and upregulated BAX, p53, and p21, causing cell-cycle arrest and apoptosis. In summary, CS-5-FU-QCT NPs hindered proliferation of HCT116 cells via ROS generation and altered the expression of key proteins in the p53/p21 axis and apoptotic machinery in a time-dependent manner.

"Jianbing" styling multifunctional electrospinning composite membranes for wound healing

Wound infection and excessive exudate can affect the process of wound healing. However, the disadvantage of the anti-microbial wound dressings is that the biological fluids are ineffectively removed. Inspired by making "Chinese Jianbing", a composite wound nano-dressing was developed consisting of a hydrophilic outer layer (chitosan&polyvinyl alcohol: CTS-PVA) and a hydrophobic inner layer (propolis&polycaprolactone: PRO-PCL) by combining casting and electrospinning methods for effective antibacterial and unidirectional removing excess biofluids. In vitro, the composite wound nano-dressing of PRO-PCL and CTS-PVA (PPCP) could strongly inhibit Pseudomonas aeruginosa. Furthermore, PPCP wound dressing had excellent antioxidant properties and blood coagulation index for effective hemostatic. Importantly, it had a preferable water absorption for removing excess biofluid. In vivo, it had anti-inflammatory properties and promoted collagen Ⅰ preparation, which realized 80% wound healing on day 7. In short, the PPCP wound dressing provides a new direction and option for antibacterial and removes excess biofluid.

Advanced Biomaterials, Coatings, and Techniques: Applications in Medicine and Dentistry

The field of biomaterials is very extensive, encompassing both the materials themselves and the manufacturing methods, which are constantly developing [...]

Surface modification strategies to improve titanium hemocompatibility: a comprehensive review

Titanium and its alloys are widely used in different biomaterial applications due to their remarkable mechanical properties and bio-inertness. However, titanium-based materials still face some challenges, with an emphasis on hemocompatibility. Blood-contacting devices such as stents, heart valves, and circulatory devices are prone to thrombus formation, restenosis, and inflammation due to inappropriate blood-implant surface interactions. After implantation, when blood encounters these implant surfaces, a series of reactions takes place, such as protein adsorption, platelet adhesion and activation, and white blood cell complex formation as a defense mechanism. Currently, patients are prescribed anticoagulant drugs to prevent blood clotting, but these drugs can weaken their immune system and cause profound bleeding during injury. Extensive research has been done to modify the surface properties of titanium to enhance its hemocompatibility. Results have shown that the modification of surface morphology, roughness, and chemistry has been effective in reducing thrombus formation. The main focus of this review is to analyze and understand the different modification techniques on titanium-based surfaces to enhance hemocompatibility and, consequently, recognize the unresolved challenges and propose scopes for future research.

Chitosan-Based Anti-Oxidation Delivery Nano-Platform: Applications in the Encapsulation of DHA-Enriched Fish Oil

Refined cobia liver oil is a nutritional supplement (CBLO) that is rich in polyunsaturated fatty acids (PUFAs), such as DHA and EPA; however, PUFAs are prone to oxidation. In this study, the fabrication of chitosan-TPP-encapsulated CBLO nanoparticles (CS@CBLO NPs) was achieved by a two-step method, including emulsification and the ionic gelation of chitosan with sodium tripolyphosphate (TPP). The obtained nanoparticles were inspected by dynamic light scattering (DLS) and showed a positively charged surface with a z-average diameter of between 174 and 456 nm. Thermogravimetric analysis (TGA) results showed the three-stage weight loss trends contributing to the water evaporation, chitosan decomposition, and CBLO decomposition. The loading capacity (LC) and encapsulation efficiency (EE) of the CBLO loading in CS@CBLO NPs were 17.77-33.43% and 25.93-50.27%, respectively. The successful encapsulation of CBLO in CS@CBLO NPs was also confirmed by the Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. The oxidative stability of CBLO and CS@CBLO NPs was monitored by FTIR. As compared to CBLO, CS@CBLO NPs showed less oxidation with a lower generation of hydroperoxides and secondary oxidation products after four weeks of storage. CS@CBLO NPs are composed of two ingredients that are beneficial for health, chitosan and fish oil in a nano powdered fish oil form, with an excellent oxidative stability that will enhance its usage in the functional food and pharmaceutical industries.

Loading Gentamicin and Zn2+ on TiO2 Nanotubes to Improve Anticoagulation, Endothelial Cell Growth, and Antibacterial Activities

Titanium and its alloys are widely used in blood-contacting implantable and interventional medical devices; however, their biocompatibility is still facing great challenges. In the present study, in order to improve the biocompatibility and antibacterial activities of titanium, TiO2 nanotubes were firstly in situ prepared on the titanium surface by anodization, followed by the introduction of polyacrylic acid (PAA) and gentamicin (GS) on the nanotube surface by layer-by-layer assembly, and finally, zinc ions were loaded on the surface to further improve the bioactivities. The nanotubes displayed excellent hydrophilicity and special nanotube-like structure, which can selectively promote the albumin adsorption, enhance the blood compatibility, and promote the growth of endothelial cells to some degree. After the introduction of PAA and GS, although the superhydrophilicity cannot be achieved, the results of platelet adhesion, cyclic guanosine monophosphate (cGMP) activity, hemolysis rate, and activated partial thromboplastin time (APTT) showed that the blood compatibility was improved, and the blood compatibility was further enhanced after zinc ion loading. On the other hand, the modified surface showed good cytocompatibility to endothelial cells. The introduction of PAA and zinc ions not only promoted the adhesion and proliferation of endothelial cells but also upregulated expression of vascular endothelial growth factor (VEGF) and nitric oxide (NO). The slow and continuous release of GS and Zn2+ over 14 days can significantly improve the antibacterial properties. Therefore, the present study provides an effective method for the surface modification of titanium-based blood-contacting materials to simultaneously endow with good blood compatibility, endothelial growth behaviors, and antibacterial properties.

Fabrication of nanostructured multi-unit vehicle for intestinal-specific delivery and controlled release of peptide

An oral multi-unit delivery system was developed by incorporating the nanoparticle (NP) into the nanofiber mat and its efficiency for intestinal-specific delivery and controlled release of a peptide (insulin) was investigated. Initially, the influence of deacetylation degree (DD) of chitosan and ionic gelation methods on the properties of NPs was studied. High DD (95%) chitosan was attributed to higher encapsulation efficiency and stability when crosslinked with polyanion tripolyphosphate. Subsequently, the multi-unit system was fabricated using a pH-sensitive polymer (sodium alginate) as the coating layer to further encapsulate the NP. Fiber mat with an average diameter of 481 ± 47 nm could significantly decrease the burst release of insulin in acidic condition and release most amount of insulin (>60%) in the simulated intestinal medium. Furthermore, the encapsulated peptide remained in good integrity. This multi-unit carrier provides the better-designed vehicle for intestinal-specific delivery and controlled release of the peptide.

Development of an electrospun polycaprolactone/silk scaffold for potential vascular tissue engineering applications

Long-distance (⩾10 mm) arterial vascular defect injury was a massive challenge affecting human health. Compared with autologous transplantation, tissue-engineered scaffolds such as biocompatible silk fibroin (SF) scaffolds have been developed because they exhibit equivalent functional repair effects without adverse reactions. However, its mechanical strength and structural stability needed to be further improved to match the longer repair cycle of blood vessels while maintaining the original biological safety. Hence, we designed and prepared SF and hydrophobic polycaprolactone (PCL) composite microfibers by an improving electrospinning method. It was found that when the weight ratio of PCL to SF was 1: 1, a microfiber scaffold with high strength (6.16 N) and minimum degradability can be obtained. More importantly, compared with natural silk fibroin, the novel composite microfiber scaffolds can slightly inhibit cell infiltration and inflammation through co-culture with HUVECs in vitro and rabbit back transplantation in vivo. Furthermore, the fabricated scaffolds also demonstrated excellent structural stability in vivo because of the well-organized PCL doping in the structure. All these results indicated that the novel PCL/SF composite microfiber scaffolds were promising candidates for vascular tissue engineering applications.

Nanoparticles in Polyelectrolyte Multilayer Layer-by-Layer (LbL) Films and Capsules—Key Enabling Components of Hybrid Coatings

Originally regarded as auxiliary additives, nanoparticles have become important constituents of polyelectrolyte multilayers. They represent the key components to enhance mechanical properties, enable activation by laser light or ultrasound, construct anisotropic and multicompartment structures, and facilitate the development of novel sensors and movable particles. Here, we discuss an increasingly important role of inorganic nanoparticles in the layer-by-layer assembly—effectively leading to the construction of the so-called hybrid coatings. The principles of assembly are discussed together with the properties of nanoparticles and layer-by-layer polymeric assembly essential in building hybrid coatings. Applications and emerging trends in development of such novel materials are also identified.

Optimization of Thiolated Chitosan Nanoparticles for the Enhancement of in Vivo Hypoglycemic Efficacy of Sitagliptin in Streptozotocin-Induced Diabetic Rats

Sitagliptin (SGN) is an antidiabetic drug used for treatment of diabetes mellitus type II. The objectives of this study were to formulate SGN in form of thiolated chitosan (TC) nanoparticles to enhance the mucoadhesion properties of SGN to the gastrointestinal tract, prolong drug release, decrease side effects, and enhance patient compliance. Seventeen batches of SGN-TC nanoparticles were designed by Box-Behnken design and prepared using the ionic gelation method using tripolyphosphate (TPP) as crosslinking agent. The prepared formulations were evaluated for particle size, entrapment efficiency %, and in vitro drug release. Based on the results of optimization, three formulations (F1-F3) were prepared with different drug polymer ratios (1:1, 1:2, and 1:3). The mucoadhesion study and in vivo hypoglycemic activity of three formulations were evaluated in comparison to free SGN in streptozotocin (STZ)-induced diabetic rats. The seventeen SGN-TC nanoparticles showed small particle sizes, high entrapment efficiency, and prolonged drug release. The concentration of TC polymers had highest effect on these responses. The percentage of SGN-TC nanoparticles adhered to tissue was increased and the release was prolonged as the concentration of TC polymer increased (F3 > F2 > F1). The hypoglycemic effect of SGN-TC nanoparticles was significantly higher than resulted by free SGN. It was concluded that TC nanoparticles had the ability to enhance the mucoadhesion properties of SGN and prolong the drug release. SGN-TC nanoparticles significantly reduced plasma glucose levels compared to free SGN in STZ-induced diabetic rats.