•We developed injectable Dox-chitin-PLA CNGs for liver cancer.•Chitin-PLA CNGs showed controlled swelling and degradation and non-hemolytic.•Chitin-PLA CNGs showed sustained drug release of ...Dox.•Dox-chitin-PLA CNGs showed dose dependent cytotoxicity toward HepG2 cells.
Hepatic carcinoma (HCC) is one of the most common cancer and its treatment has been considered a therapeutic challenge. Doxorubicin (Dox) is one of the most important chemotherapeutic agents used in the treatment for liver cancer. However, the efficacy of Dox therapy is restricted by the dose-dependent toxic side effects. To overcome the cardiotoxicity of Dox as well as the current problems of conventional modality treatment of HCC, we developed a locally injectable, biodegradable, and pH sensitive composite nanogels for site specific delivery. Both control and Dox loaded composite nanogel systems were analyzed by DLS, SEM, FTIR and TG/DTA. The size ranges of the control composite nanogels and their drug loaded counterparts were found to be 90±20 and 270±20nm, respectively. The control chitin-PLA CNGs and Dox-chitin-PLA CNGs showed higher swelling and degradation in acidic pH. Drug entrapment efficiency and in vitro drug release studies were carried out and showed a higher drug release at acidic pH compared to neutral pH. Cellular internalization of the nanogel systems was confirmed by fluorescent microscopy. The cytotoxicity of the composite nanogels was analyzed toward HepG2 (human liver cancer) cell lines. Furthermore, the results of in vitro hemolytic assay and coagulation assay substantiate the blood compatibility of the system. Overall Dox-chitin-PLA CNGs system could be a promising anticancer drug delivery system for liver cancer therapy.
A new mineralized collagen matrix combined with or without growth factor was used for the posterolateral spinal fusion in the rabbit lumbar spine.
The availability of a new osteoconductive matrix ...with or without recombinant osteoinductive growth factors offers a possible alternative to the use of autogenous bone for grafting indications. This study evaluated the bone-forming activity of the biomimetic matrix: nano-hydroxyapatite/collagen/polylactic acid (nHAC/PLA) combined without or with recombinant human bone morphogenetic protein-2 (rhBMP-2) in a rabbit posterolateral spinal fusion.
Many bone grafting materials such as titanium alloy, ceramics, and polymers were used to repair bony defects. However, each has specific disadvantaged. The permanent implantation still has possibility to be eroded in vivo, which is caused by late breakdown and abscess formation. The acidic outcome of polymer biodegradation was also negatively affected in the later-stage results of bone repair. It needed a promising material for an alternative to the use of autogenous bone for grafting indications.
Sixty-four rabbits were randomly divided into four groups: autologous iliac crest bone group (ACB), nHAC/PLA composite group (nHAC/PLA), autologous iliac crest bone mixed with nHAC/PLA composite group (ACB + nHAC/PLA), nHAC/PLA composite with recombinant human BMP-2 group (nHAC/PLA + rhBMP-2). The lumbar intertransverse process fusions were assessed by manual palpation, radiographic, histologic, and mechanical strength, and scanning electronic microscopy (SEM) in a 10-week observation.
Optimal formulations of the ACB + nHAC/PLA and nHAC/PLA + rhBMP-2 groups were shown to perform similar to ACB in both the fusion ratio and mechanical strength in the 6 and 10 weeks after surgery. From the microstructure analysis of the samples, there was no negative effect when the compound implanted this composite with autogenous iliac crest, and there was also new bone-like tissue formation implanted this composite without combined rhBMP-2 early at the second week after surgery.
This study shows the effective results of nHAC/PLA in rabbit posterolateral spinal fusion combined with rhBMP-2. It is an alternative method to autograft by compounding this osteoconductive matrix with growth factors.
Polylactic acid (PLA) and PLA-hydroxyapatite (Hap)-chitosan (CS) composite have been extensively used for biomedical applications, and numerous studies were reported on their recycling in the past ...two decades. But hitherto less has been testified on the effect of primary (1°) and secondary (2°) recycling of PLA and its composite for biomedical and sensing applications. In this study, 1° and 2° recycling of PLA and PLA-Hap-CS composite were performed with twin-screw extrusion (TSE) followed by preparation of feedstock strand for 3D printing. Further rheological, electrical, mechanical, morphological properties and bond characteristics of prepared strands were compared for 1° and 2° recycled PLA and its composite. Results of the study suggest that while 1° recycling of PLA there was a 73.99% increase in flowability (after 1st cycle) whereas in the case of 2° recycling of PLA flowability increase was 125.83%. As regards tensile properties, it was observed that while 1° recycling of PLA (after 1st cycle), there was a reduction of 8.86% in peak strength, whereas, in the case of 2° recycling, 23.25% reduction was noticed. On the other hand, significant improvement in Young’s modulus (
E
) was noticed while 1° and 2° recycling after the 2nd cycle. Further, based on the surface analysis of the prepared feedstock strand, it was observed that the porosity was increased in both 1° and 2° recycling of PLA and its composite. The electrical characteristics reveal that the electric resistance was increased for both 1° and 2° recycling. The study suggests that when the strand prepared by TSE is recycled 2nd time (for both 1° and 2° recycling), it shows better sensing properties for biomedical applications. The results are supported with scanning electron microscopy (SEM), energy-dispersive spectroscopy, Fourier transformed infrared spectroscopy-attenuated total reflectance analysis.
In this article, we investigated the properties of thermoplastic starch (TPS) with pineapple leaf fiber (PALF)/poly(lactic acid) (PLA) composite compared to both TPS with a PALF composite and TPS/PLA ...blend. The composite is prepared by a single-screw extruder. It appears that the TPS with PALF/PLA composite gives better mechanical properties and water resistance than the TPS/PLA blend, but it presents the same flow behavior (based on the power law index) as the PLA alone.
Recently, conductive polymers have attracted attention in the field of advanced materials. Conducting polymers include polypyrrole (PPy), which is a material with commercial applications due to its ...stability and electrical conductivity. As technology demands increasingly flexible devices, PPy was mixed with a biodegradable and flexible polymer, polylactic acid, in order to create a composite possessing of newer properties. As it is a new material, thermal properties of this composite such as thermal diffusivity, thermal effusivity, specific heat capacity, and thermal conductivity have been investigated through the application of photoacoustic calorimetry and photopyroelectric techniques.
Toddy palm fruit have an apparent density below 0.8 g/cm3 and offer an interesting lightweight construction potential in polylactide (PLA) composites reinforced with 37 mass-% fibres. Single fibre ...bundles show similar mechanical properties compared with coir: tensile strength
of 240 MPa, Young's modulus of 3.8 GPa and an elongation at break of 31%. However, density and diameter (∼ 50 μm) of fruit fibre bundles are significantly lower. The compression moulded composites have a density of 0.9 g/cm3 and achieved an unnotched Charpy impact strength
of 12 kJ/m2, a tensile strength of 25 MPa, Young's modulus of 1.9 GPa and an elongation at break of 9%. Due to the high porosity of the composites and the different stress-strain behaviour of fibre and matrix the fibre-reinforcement potential could not be fully used. Maximum stress
of the composite was reached at the elongation at break of the PLA-matrix (∼2%) while the fibre achieved its maximum stress at an elongation of ∼31%. After reaching the maximum stress of the composite, the fibres were pulled out from the matrix with low energy absorption, resulting
in a decrease in stress and a limited reinforcement potential. Additionally, the study investigates whether an insect attack by the Asian fruit fly on the mesocarp has a significant influence on the mechanical fibre characteristics. The results have shown that only the rough surface of the
fibre bundles is smoothed by insect infestation. The mechanical properties were not significantly affected. For this reason insect-infested fruits of the toddy palm, which are no longer suitable for food production, can be used for the production of sustainable composite materials.
Silicon oxide (SiO
x
) films are widely used as barrier layers in different types of commodity packaging and have caught the interest of manufacturers and researchers alike owing to their high ...barrier functionality, good acid and alkali resistance, ability to withstand high-temperature and microwave treatments, and good transparency. In this study, we first synthesized polylactic acid (PLA) films by extrusion calendaring and then deposited a SiO
x
layer on the PLA films by plasma-enhanced chemical vapor deposition to prepare SiO
x
/PLA composite films. We then evaluated the barrier functionality of the SiO
x
layer and elucidated its underlying mechanism. We also analyzed its effect on the mechanical properties of the composite films by comparing the oxygen and water vapor transmission rates, soil degradation performances, and surface morphologies of the two types of synthesized films (uncoated and coated with SiO
x
). The results showed that, because of the SiO
x
layer, the barrier properties and mechanical properties of the SiO
x
/PLA composite films were better than those of the uncoated films. In particular, the oxygen and water vapor transmission rates of the composite films were approximately 8–10 and 6–8 times lower, respectively, than those of the uncoated PLA films. In addition, the SiO
x
layer lowered the rate of soil degradation of the composite films, owing to which the weight-loss rates of the composite films were also lower than those of the uncoated films. Further, the tensile strengths and elongations at break of the composite films were higher because of the SiO
x
layer.
Graphical Abstract
A synthesis of nano-hydroxyapatite:polylactide acid (n-HA:PLA) composites based on natural materials has been performed. The synthesis was performed using sonication method, with a variation of ...n-HA:PLA ratio of 90:10, 80:20, 70:30, 60:40, 50:50 in %wt. The crystal structure and morphology of the sample were characterized by using X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The bioactivity and biodegradable tests were performed in vitro using Krebs solution. Meanwhile, the biocompatibility test was performed by a separate bath organ method. The results show that for all compositions of n-HA:PLA exhibit a biocompatible characteristic. The sample with a ratio of 90:10 %wt shows higher bioactivity and biodegradability properties than other compositions. Our result would give a good understanding of the synthesis and biocompatibility, bioactivity, and biodegradability of n-HA:PLA composite, which is crucial for bone regeneration.
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