Progress in Biomaterials最新文献

Ambroxol hydrochloride (AH), a secretion-releasing expectorant, is a good candidate for sustained delivery. Mucilages are biodegradable, inexpensive carriers in microsphere formulations. The study aimed to prepare microspheres of AH using Okra mucilage obtained from pods of Abelmoschus esculentus combined with sodium alginate at various polymer/drug ratios. Okra mucilage was characterized for morphology, swelling, viscosity and flow properties. AH microspheres were prepared by ionic emulsification method and characterized using size, entrapment efficiency, swelling index and dissolution time (t₅₀). A full 2 by 3 factorial experimental design using three factors (Okra mucilage/alginate ratio X₁; drug/polymer ratio X₂; and polymer concentration X₃), each at two levels, was used to determine the effects of formulation variables on the responses. Optimized formulations of AH microspheres had sizes ranging from 250.91 ± 16.22 to 462.10 ± 23.85 µm; swelling index 1.35 ± 0.05 and 3.20 ± 0.03 and entrapment 55.70 ± 3.55-94.11 ± 4.50%. The microspheres exhibited sustained release of AH over a prolonged period as revealed by the dissolution time (t₅₀) 2.85 ± 1.03-7.50 ± 0.96 h. Drug release kinetics generally followed zero order, implying that the process is constant and independent of the initial concentration of drug. Polymer concentration had the highest influence on microsphere size, entrapment efficiency and dissolution time while Okra/alginate ratio had the highest influence on swelling. Okra mucilage was a suitable polymer that could serve as an alternative to synthetic polymers in sustaining the release of ambroxol hydrochloride.

Since surface plays a key role in bioactivity, the response of the host to the biomaterial will determine the success or failure of the prosthesis. The purpose of this study is to make an exhaustive analysis of the histological and histochemical characteristics of new bone tissue around Zr implants anodized at 60 V (Zr60) supported by histomorphometric methods in a rat model. Fibrous tissue was observed around the control implants (Zr0) and osteoblasts were identified on the trabeculae close to the implantation site that showed typical cytological characteristics of active secretory cells, regardless of the surface condition. The histomorphometrical analysis revealed a significant increase in cancellous bone volume, trabecular thickness and in trabecular number together with a decrease in trabecular separation facing Zr60. TRAP staining showed that there was a relative increase in the number of osteoclasts for Zr60. In addition, a larger number of osteoclast with a greater number of nuclei were detected in the tibiae for Zr60. This research demonstrated that the new bone microarchitecture in contact with Zr60 is able to improve the early stages of the osseointegration process and consequently the primary stability of implants which is a crucial factor to reduce recovery time for patients.

The current study aimed to investigate the potential of carbon nanofibers to promote peripheral nerve regeneration. The carbon nanofiber-imbedded scaffolds were produced from polycaprolactone and carbon nanofibers using thermally induced phase separation method. Electrospinning technique was utilized to fabricate polycaprolactone/collagen nanofibrous sheets. The incorporation of carbon nanofibers into polycaprolactone's matrix significantly reduced its electrical resistance from 4.3 × 10⁹ ± 0.34 × 10⁹ Ω to 8.7 × 10⁴ ± 1.2 × 10⁴ Ω. Further in vitro studies showed that polycaprolactone/carbon nanofiber scaffolds had the porosity of 82.9 ± 3.7% and degradation rate of 1.84 ± 0.37% after 30 days and 3.58 ± 0.39% after 60 days. The fabricated scaffolds were favorable for PC-12 cells attachment and proliferation. Neural guidance channels were produced from the polycaprolactone/carbon nanofiber composites using water jet cutter machine then incorporated with PCL/collagen nanofibrous sheets. The composites were implanted into severed rat sciatic nerve. After 12 weeks, the results of histopathological examinations and functional analysis proved that conductive conduit out-performed the non-conductive type and induced no toxicity or immunogenic reactions, suggesting its potential applicability to treat peripheral nerve damage in the clinic.

Nowadays, bone diseases and defects as a result of trauma, cancers, infections and degenerative and inflammatory conditions are increasing. Consequently, bone repair and replacement have been developed with improvement of orthopedic technologies and biomaterials of superior properties. This review paper is intended to sum up and discuss the most relevant studies performed in the field of bone biology and bone regeneration approaches. Therefore, the bone tissue regeneration was investigated by synthetic substitutes, scaffolds incorporating active molecules, nanomedicine, cell-based products, biomimetic fibrous and nonfibrous substitutes, biomaterial-based three-dimensional (3D) cell-printing substitutes, bioactive porous polymer/inorganic composites, magnetic field and nano-scaffolds with stem cells and bone-biomaterials interface studies.

Active targeting of folic acid and passive targeting of magnetic nanoparticles to bring about co-delivery of hydrophobic chemotherapeutic agents were the focus of this work. Co-precipitation in alkaline environment was employed for synthesizing Fe₃O₄ nanoparticles and stabilized by oleic acid. Aqueous dispersibility of oleic acid coated nanoparticles was brought about by folic acid modified Pluronic F127 and Pluronic F127 mixture. Folic acid is used as a targeting agent which was joined to Pluronic F127 via diethylene glycol bis(3-aminopropyl) ether spacer. The nanocomposite was used to delivery hydrophobic anticancer drugs, paclitaxel, and curcumin. Successful modification at each step was confirmed by FTIR and NMR. Quantitative analysis of attached folic acid indicated a total of 84.34% amount of conjugation. Nanoparticles characterization revealed the hydrodynamic size of and nanocomposite to be 94.2 nm nanometres. Furthermore, transmission electron micrograph reveals the size of the nanoparticle to be 12.5 nm hence also shows the superparamagnetic activity. Drug encapsulation efficiency of 34.7% and 59.5% was noted for paclitaxel and curcumin, respectively. Cytotoxic property of drug-loaded nanocomposites was increased in case of folic acid functionalized nanoparticles and further increased in the presence of an external magnetic field. Cellular uptake increased in the folic acid conjugated sample. Further many folds in the presence of an external magnetic field.

Fabrication of scaffolds from biomaterials for restoration of defected mandible bone has attained increased attention due to limited accessibility of natural bone for grafting. Hydroxyapatite (Ha), collagen type 1 (Col1) and chitosan (Cs) are widely used biomaterials which could be fabricated as a scaffold to overcome the paucity of bone substitutes. Here, rabbit Col1, shrimp Cs and bovine Ha were extracted and characterized with respect to physicochemical properties. Following the biocompatibility, degradability and cytotoxicity tests for Ha, Col1 and Cs a hydroxyapatite/collagen/chitosan (Ha·Col1·Cs) scaffold was fabricated using thermally induced phase separation technique. This scaffold was cross-linked with (1) either glutaraldehyde (GTA), (2) de-hydrothermal treatment (DTH), (3) irradiation (IR) and (4) 2-hydroxyethyl methacrylate (HEMA), resulting in four independent types (Ha·Col1·Cs-GTA, Ha·Col1·Cs-IR, Ha·Col1·Cs-DTH and Ha·Col1·Cs-HEMA). The developed composite scaffolds were porous with 3D interconnected fiber microstructure. However, Ha·Col1·Cs-IR and Ha·Col1·Cs-GTA showed better hydrophilicity and biodegradability. All four scaffolds showed desirable blood biocompatibility without cytotoxicity for brine shrimp. In vitro studies in the presence of human amniotic fluid-derived mesenchymal stem cells revealed that Ha·Col1·Cs-IR and Ha·Col1·Cs-DHT scaffolds were non-cytotoxic and compatible for cell attachment, growth and mineralization. Further, grafting of Ha·Col1·Cs-IR and Ha·Col1·Cs-DHT was performed in a surgically created non-load-bearing rabbit maxillofacial mandible defect model. Histological and radiological observations indicated the restoration of defected bone. Ha·Col1·Cs-IR and Ha·Col1·Cs-DHT could be used as an alternative treatment in bone defects and may contribute to further development of scaffolds for bone tissue engineering.