Polimery w medycynie最新文献

Coronavirus Disease 2019 (COVID-19) pandemic caused an increase in the demand for personal protective equipment (PPE) and disruptions in production chains, resulting in an acute shortage of PPE. A possible solution to this problem was additive manufacturing (AM) technology - allowing for a quick start of the production of PPE and potentially able to meet the demand until the production is restored. In addition, AM allows for the production of PPE prototypes with potentially greater comfort of use or degree of protection. In order to assess the production of PPE in AM during the COVID-19 pandemic, previously published articles in this field were analyzed. After analyzing abstracts and full texts, 30 original works were selected from the initially collected 487 articles. Based on the analyzed literature, it was found that there are not enough studies comparing traditional and AM PPE as well as not enough comparisons of the different types of AM PPE with each other. In many cases, researchers focused only on the subjective assessment of the comfort of using PPE, without assessing their effectiveness in preventing infections. Despite that, AM has a great potential to quickly produce lacking PPE. Respirators and shields made by AM were rated by the vast majority of users as comfortable to wear. Some of the respirators could be adapted to a specific user, by designing on the basis of a face scan or after warming up the finished print and modeling the shape.

Fucoidans represent the sulfated heteropolysaccharides that possess a wide range of important pharmacological properties. The properties of a fucoidan depend on several factors, including the molecular weight and the way of extraction. However, the selection of an optimal depolymerization method is necessary to enhance its therapeutic applications. Reducing the molecular weight of fucoidans will make it possible to use them in creating nanoparticles and nanocarriers for, among others, the targeted drug delivery. The molecular mass of the polymer can be changed by means of various methods of depolymerization. In this work, the possibility of application of ultrasonic destruction for decrease in the size of fucoidan molecules for the purpose of expansion of opportunities and spheres of their therapeutic application is considered. This is one of the simple and effective methods of depolymerization of fucoidan, which leads to a decrease in molecular weight without significant structural changes in macromolecules. In addition, methods and potential applications of the ultrasonic extraction of fucoidan from seaweed and the possibilities of their combination are discussed, as well as other physical or chemical methods of extraction.

Wound infection may occur in acute and chronic wounds, wounds resulting from surgery or traffic accidents, and burns. Regardless of the extent and cause of the wound, prompt treatment is essential in reducing the patient's pain and limiting the spread of contamination. Improper wound care and associated chronic diseases may hinder the therapeutic success. Bacterial cellulose (BC) is highly biocompatible and has no cytotoxic effect on cells engaged in wound healing, such as fibroblasts and keratinocytes. Its high hydration level guarantees the maintenance of a moist wound environment. High mechanical strength, flexibility and resistance to damage make BC a promising material for dressings. Unfortunately, it does not display an inhibitory effect on bacterial growth. Introducing antimicrobial agents into the structure of BC has been a subject of many studies. This paper aims to present the latest reports on the possibility of the absorption of bacteriostatic and bactericidal agents in BC, such as metal particles, essential oils, antibiotics, antiseptics, and wound irrigation solutions. Moreover, the modifications in BC culture and post-production treatments in order to improve its physical properties are discussed.

Background: Microbial pathogens, mainly bacteria, are a major cause of food spoilage resulting in several foodborne diseases. Food spoilage can be prevented by the application of chemical preservatives in the food industry but such process has harmful effects on human health and causes the introduction of chemicals in several food chains, leading to toxicity and long-term complications. Due to such adverse effects, the need to find natural preservatives that are safer to use, effective and less complicated is increasing.

Objectives: This study is based on plant extracts that play a major role in microbicidal action (the use of natural preservatives is preferred over chemical ones). Antimicrobial action of different plant extracts was assessed using Staphylococcus aureus and Escherichia coli as experimental bacterial strains.

Material and methods: Ethanolic extracts of different plants like Punica granatum, Acacia catechu and Phyllanthus emblica were highly effective against the both analyzed bacterial strains at a dosage of 10 mg/mL, while the extracts of Ocimum bacilicum and Quercus infectoria were effective only against S. aureus and E. coli, respectively.

Results: Punica granatum and Phyllanthus emblica extracts were found to be the most effective and exhibited bacteriostatic and bactericidal activities against the highly infectious strains of pathogenic bacteria causing food spoilage, with minimum inhibitory concentration (MIC) of 2.5 mg/mL and minimum bactericidal concentration (MBC) of 5 mg/mL.

Conclusions: The plant extracts used in the study were highly effective in reducing bacterial contamination and can be used as an alternative to chemical preservatives to avoid and control foodborne diseases and for preservation of food with no health-related hazards caused by chemicals.

Background: Pre-gelatinization is one of the most common physical methods of starch modification, which involves heating to bring about significant changes in the nature of starch, such as high swelling, loss of crystallinity, solubility in cold water, and improved pasting.

Objectives: To evaluate the structural and physicochemical properties of starch from Neorautanenia mitis tubers, and determine the effect of pre-gelatinization on the functional properties of this starch.

Material and methods: Properties of the pre-gelatinized starch (NMPS), such as flow, swelling power, hydration capacity, pH, morphology, Fourier-infrared spectroscopy (FTIR), differential scanning calorimetry, and pasting characteristics, were compared with those of the native starch (NMNS).

Results: Pre-gelatinized starch had good flow with the angle of repose at 33.69°. Carr's index was 10.90% and 7.50%, and the Hausner ratio was 1.12 and 1.05 for NMNS and NMPS, respectively. Both starches had neutral to near-neutral pH (7.00 and 6.04, respectively). The hydration capacity of NMPS (59.00%) was about 2 times higher than that of NMNS (25.80%), while the swelling power of NMPS between 40°C and 60°C was higher than that of NMNS, and maximum swelling for both starches was observed at 80°C. Morphology showed that NMNS granules were discrete, smooth and spherical, while those of NMPS were aggregated, with rough surfaces. The FTIR spectra of both starches showed identical absorption peaks but the enthalpy of gelatinization differed for both starches. The pasting properties also varied significantly among the starch samples. Native starch had better peak viscosity, breakdown viscosity and pasting temperature, while NMPS presented better trough viscosity, final viscosity, setback viscosity, and pasting time.

Conclusions: The results showed that pre-gelatinized starch from N. mitis tubers possesses high swelling and hydration abilities and significant pasting properties, and may be used as a disintegrant in solid dosage formulations and in products requiring low viscosities and bond strength.

Background: The pH of the skin surface is usually between 5.4 and 5.9 and functions as a barrier against bacteria and fungi; thus, the composition of the topically applied drug form may be of high importance for proper medication.

Objectives: To evaluate the influence of the measurement conditions in aqueous solutions of ointments, creams, and gels, which include polymeric components, on the pH and conductivity results.

Material and methods: The pH and electrolytic conductivity of aqueous dispersions of commercially available ointments, creams and gels were tested and compared to reference vehicles.

Results: The results of the dilution method measurements of the pH and electrolytic conductivity of the ointment preparations are highly diverse, ranging from 5.88 to 6.27, whereas the reference pH for Unguentum simplex was between 5.40 and 5.43. Furthermore, the measurements of the pH and electrolytic conductivity with the dilution method for creams did not provide repeatable results with a small sample size, and the pH of commercial preparations was in the range between 5.79 and 6.37, compared to the reference pH of 5.23-5.46. However, the dilution method for measurements of the pH and electrolytic conductivity was suitable for hydrogel preparations and the obtained results were repeatable in the range of 6.11-6.90, while the reference preparations were in the range of 5.19-5.62.

Conclusions: Evaluation methods of the electrolytic conductivity and pH of the preparations applied on the skin should be further evaluated; however, the pH of the commercial preparation seems to differ from the physiological skin pH, which covers the range of reference preparations.

Background: Neomycin is a natural aminoglycoside antibiotic produced by actinomycete Streptomyces fradiae. It exerts bacteriostatic and bactericidal activity against Gram-negative bacteria, certain Gram-positive bacteria and Mycobacterium tuberculosis. Neomycin inhibits the biosynthesis of bacterial proteins by impairing their life functions, leading to death of cells.

Objectives: To examine the effect of molecular weight of polylactide (PLA), the applied stabilizer as well as mixing speed used in the encapsulation process on the size of obtained spheres. Examination of the kinetics of neomycin release from the obtained PLA spheres and determination of the antimicrobial activity of the neomycin-containing spheres against selected strains of bacteria, yeast and fungi have also been necessary.

Material and methods: Polylactide (Mn 3000-40,000 g/mol) was obtained in-house. Other materials used in the study were as follows: L-lactic acid (PLLA; Mn 66,500 g/mol and 86,000 g/mol), polyvinyl alcohol (PVA) as a stabilizer of emulsion (Mw 30,000 g/mol, 130,000 g/mol; degree of hydrolysis 88%) as well as dichloromethane, p.a. and dimethyl sulfoxide (DMSO), p.a. as solvents. Distilled water was obtained in-house. Neomycin sulfate was used for encapsulation; phosphate (pH 7.2) and acetate (pH 4.5) buffers were used for the examination of the active pharmaceutical ingredient (API) dissolution profile. Antimicrobial activity was tested using commercial cell lines and the following media: Mueller-Hinton agar (MHA), Mueller-Hinton broth (MHB), yeast extract peptone dextrose (YPD), and potato dextrose agar (PDA).

Results: Neomycin-containing PLA spheres were obtained using an emulsion method. The average molecular weight of PLA, the average molecular weight of PVA and mixing speed on the size of obtained spheres were investigated. Furthermore, the profile of API dissolution from the spheres and antimicrobial activity of neomycin-containing spheres against certain strains of bacteria, yeast and fungi were determined.

Conclusions: We demonstrated that efficient encapsulation of neomycin requires spheres of a <200 mm diameter.

Poly(glycerol sebacate) (PGS) is an aliphatic polyester which attracted significant scientific attention in recent years due to its vast potential in biomedical applications with regard to tissue engineering. It has been presented in the literature in the form of 2D films, porous scaffolds or nonwovens, to name just a few. Moreover, various applications have been proposed as a component of composite materials or polymer blends. Its physicochemical properties can be significantly adjusted by means of synthesis and post-synthetic modifications, including cross-linking or chemical modification, such as copolymerization. Many scientists have discussed PGS as a new-generation polymer for biomedical applications. Its regenerative potential has been confirmed, in particular, in tissue engineering of soft tissues (including nerve, cartilage and cardiac tissues). Therefore, we must anticipate a growing importance of PGS in contemporary biomedical applications. This brief review aims to familiarize the readers with this relatively new polymeric material for tissue engineering applications.

Natural polymers have been commonly applied in medicine and pharmacy. Their primary function is to enhance drug delivery, tissue regeneration or wound healing, and diagnostics. Natural polymers appear promising for photodynamic protocols, including photodiagnosis (PDD) and photodynamic therapy (PDT). Currently, the most challenging issue with natural polymers is to appropriately select the most effective material regarding the type of cancer treated. The technological achievements enable functionalization of natural polymers by specific antibodies, or enhancement using fluorescent or quantum dot markers for diagnostic applications. This review will discuss the types and properties of natural polymers and available applications of PDD and PDT which seem to be promising in cancer treatment. Treatment of neoplastic diseases is still a challenge for both physicians and scientists, so the search for alternative methods of treatment and diagnosis based on natural materials is relevant.

Background: Plant-extract-reduced metal nanoparticles provide means of overcoming microbial resistance. Incorporating them into appropriate pharmaceutical formulations will enhance their portability and ease of administration.

Objectives: To synthesize silver nanoparticles using methanol extracts of the seeds of Blighia sapida as capping agents and formulating the products in antimicrobial films.

Material and methods: Phytochemical screening of the methanol extract of Blighia sapida K.D. Koenig (ackee) seeds was performed and its antioxidant properties were determined using DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. The green synthesis of ackee seed extract silver nanoparticles (ASAgNPs) was accomplished with reacting 1 mM of aqueous silver nitrate (AgNO3) and the methanol extract in a flask; the bioreduction was performed at 37°C for 72 h. The resulting nanoparticles were lyophilized and characterized using UV-visible spectrophotometry, Fourier-transform infrared spectroscopy (FTIR) and photomicrography. The nanoparticles were further formulated into films using starch and carboxymethyl cellulose using the solvent evaporation method. The extract, biosynthesized nanoparticles and film formulations were screened for antimicrobial activity against several pathogens using the agar well diffusion method.

Results: The methanol seed extracts of the ackee fruit contained saponins, tannins, flavonoids, terpenoids, and anthraquinones. The extract exhibited significant antioxidant properties. The nanoparticles and film formulations had a broader range of activity against microbes than the plant extract, exhibiting significant activity against Escherichia coli ATCC 700728, Salmonella typhi ATCC 14028, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853. Activity was also observed with Candida krusei, C. albicans, and Penicillium sp. It is noteworthy that this last organism showed resistance to fluconazole.

Conclusions: Ackee seed extract silver nanoparticles exhibited a synergistic antimicrobial activity against several pathogens. Film formulations of the nanoparticles retained this antimicrobial activity and allowed the product to be presented in a consumer-ready form.