Polimery w medycynie最新文献

Background: Skin, the first barrier to pathogens, loses its integrity and function after an injury. The presence of an antibacterial dressing at the wound site may prevent bacterial invasion and also improve the healing process.

Objectives: The current study aimed to fabricate a biomimetic membrane with antibacterial properties for healing chronic wounds.

Material and methods: The membranes, fabricated through electrospinning, are comprised of poly(ethylene oxide) (PEO) and zinc oxide nanoparticles (ZnO-NPs) as the main biomaterial and antibacterial agent, respectively. Antibacterial activity, cell attachment and viability were tested to evaluate the biological properties of the membranes. The optimal cell compatible concentration of ZnO-NPs was determined for further studies. In vitro characterization of the membranes was performed to confirm their suitable properties for wound healing.

Results: The antibacterial PEO/ZnO-NP membrane containing 2% of nanoparticles showed no cell toxicity, and human fibroblast cells were able to adhere and proliferate on the scaffold. The in vitro results from the tensile test, wettability, porosity, and protein adsorption revealed appropriate properties of the membrane as a scaffold for skin tissue engineering.

Conclusions: Synthetic polymers have been widely used for tissue engineering applications. The proper characteristics of PEO nanofibers, including a high ratio of surface/volume, moderate hydrophilicity and good mechanical properties, make this polymer interesting for skin regeneration. The results demonstrate the potential of the antibacterial PEO/ZnO-NP membrane to be used as an engineered scaffold to improve the wound healing process.

In the development of drug delivery systems, an oral drug delivery system is the preferred route of drug administration. Many components play an important role in developing a drug delivery system. Amongst those components, polymers have evolved with these systems. Macromolecule compounds consisting of many monomer units which are joined to each other by different bonds are known as polymers. For drugs that are absorbed primarily in the upper gastrointestinal tract, floating drug delivery systems offer an additional advantage. The purpose behind this review was to focus on different types of floating drug delivery systems and different types of polymers used in floating drug delivery systems, focusing on acrylic acid derivatives and their applications. In this review, the main emphasis is on acrylic acid derivative polymers, their formulation and grades, and various patents on these types of polymers. Based on the literature survey, mainly 2 types of polymers are used in this drug delivery system; i.e., natural and synthetic. Examples of natural polymers are xanthan gum, guar gum or chitosan, and synthetic polymers include acrylic acid derivatives and hydroxylpropyl methylcellulose (HPMC). Eudragit and Carbopol are the most widely used acrylic acid derivatives.

Background: Green route biosynthesis of silver nanoparticles using Trichoderma viride (T. viride) filtrate (TVFSNPs) can serve as an alternative to antibiotics and as an effective drug delivery to combat cancer and act as an immune-stimulator.

Objectives: To biosynthesize silver nanoparticles (SNPs) with T. viride filtrate using green route and to characterize and determine the cytotoxic and immunomodulatory potential of nanoparticles.

Material and methods: Trichoderma viride filtrate was used for biosynthesizing SNPs. The biosynthesized SNPs were characterized using UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The cytotoxic properties against Hep‑2C and rotavirus and the immunomodulatory potential were evaluated.

Results: Trichoderma viride filtrate was able to bio-reduce AgNO3 to SNPs. The surface plasmon resonance peak was at 450 nm. The presence of aldehydes, amino acids, ethers, esters, carboxylic acids, hydroxyl groups, and phenol among others indicates the capping and stabilization of proteins in the nanoparticles. The nanoparticles were spherical with a size of 0.1-10.0 nm. The EDX analysis revealed a strong signal of silver (Ag). The TVFSNPs had a cytotoxic effect on Hep2C and rotavirus in a dose-dependent manner and increased the production of immunoglobulin (Ig) A (IgA) and IgM.

Conclusions: Trichoderma viride filtrate contained some biochemicals that can bio-reduce silver nitrate (AgNO3) for SNPs biosynthesis. The anticancer and immunostimulatory potential justifies the biomedical application and biotechnological relevance of T. viride.

Free light chains accumulation is the reason of kidney injury in patients with multiple myeloma. The removal of free light chains can improve patients prognosis and survival, and in some cases allows for dialysotherapy discontinuation. Unfortunately, conventional dialysis is not effective enough in terms of free light chains removal. New high cut-off (HCO) techniques remove free light chains more effectively than conventional dialysis. In some cases, this technique may turn out better than hemodiafiltration. However, there are some differences between specific techniques in the removal of kappa and lambda light chains. Lambda light chains are better removed by polymethyl methacrylate membranes with a change of filter during dialysis. Kappa light chains are thoroughly removed by polymethyl methacrylate membranes and HCO (35,000 Da) polysulfone membranes. Unfortunately, it is very difficult to differentiate between the effect of HCO dialysis therapy and concomitant chemotherapy because some of the data is not fully conclusive. Using the proper technique for an individual patient may give optimally effective treatment results.

Background: Using positron annihilation lifetime spectroscopy (PALS), microstructural changes in commercial dental restorative composites under light-curing polymerization were identified as a modification in mixed positron/Ps trapping, where the decay of positronium (Ps; the bound state of positrons and electrons) is caused by free-volume holes mainly in the polymer matrix, and positron trapping is defined by interfacial free-volume holes in a mixed filler-polymer environment. In loosely packed composites with a filler content of <70-75%, this process was related to the conversion of Ps-to-positron trapping.

Objectives: To disclose such peculiarities in densely packed composites using the example of he commercially available acrylate-based composite ESTA-3® (ESTA Ltd., Kiev, Ukraine), which boasts a polymerization volumetric shrinkage of only 1.5%.

Material and methods: ESTA‑3® was used as a commercially available acrylate-based dental restorative composite. A fast-fast coincidence system of 230‑ps resolution based on 2 photomultiplier tubes coupled to a BaF2 detector and ORTEC® electronics was used to register lifetime spectra in normal-measurement statistics. The raw PAL spectra were treated using x3-x2-CDA (coupling decomposition algorithm).

Results: The annihilation process in the densely packed dental restorative composites (DRCs), as exemplified by the commercially available acrylate-based composite ESTA‑3®, is identified as mixed positron/ Ps trapping, where o-Ps decay is caused by free-volume holes in the polymer matrix and interfacial filler-polymer regions, and free positron annihilation is defined by free-volume holes between filler particles. The most adequate model-independent estimation of the polymerization volumetric shrinkage can be done using averaged positron annihilation lifetime. A meaningful description of the transformations in Psand positron-trapping sites under light curing can be developed on the basis of a semiempirical model exploring x3‑x2‑CDA. There is a strong monolithization of agglomerated filler nanoparticles in these composites, caused by the photo-induced disappearing of positron traps at the cost of Ps-decaying holes.

Conclusions: Governing the polymerization void-evolution process in densely packed DRC ESTA‑3® occurs mainly in the filler sub-system as positron-to-Ps trapping conversion, which is the reason for the low corresponding volumetric shrinkage.