High-performance capillary electrophoresis to determine intact keratan sulfate and hyaluronic acid in animal origin chondroitin sulfate samples and food supplements

A review of glycosaminoglycan-modified electrically conductive polymers for biomedical applications

The application areas of electrically conductive polymers have been steadily growing since their discovery in the late 1970s. Recently, electrically conductive polymers have found their way into biomedicine, allowing the realization of many relevant applications ranging from bioelectronics to scaffolds for tissue engineering. Extracellular matrix components, such as glycosaminoglycans, build an important class of biomaterials that are heavily researched for biomedical applications due to their favorable properties. Due to their highly anionic character and the presence of sulfate groups in glycosaminoglycans, these biomolecules can be employed to functionalize conductive polymers, which enables the tailorability and improvement of cell-material interactions of conductive polymers. This review paper gives an overview of recent research on glycosaminoglycan-modified conductive polymers intended for biomedical applications and discusses the effect of different biological dopants on material characteristics, such as surface roughness, stiffness, and electrochemical properties. Moreover, the key findings of the biological characterization in vitro and in vivo are summarized, and remaining challenges in the field, particularly related to the modification of electrically conductive polymers with glycosaminoglycans to achieve improved functional and biological outcomes, are discussed. STATEMENT OF SIGNIFICANCE: The development of functional biomaterials based on electrically conductive polymers (CPs) for various biomedical applications, such as neural regeneration, drug delivery, or bioelectronics, has been increasingly investigated over the last decades. Recent literature has shown that changes in the synthesis procedure or the chosen dopant could adjust the resulting material characteristics. Hence, an interesting approach lies in using natural biomolecules as dopants for CPs to tailor the biological outcome. This review comprehensively summarizes the state of the art in the field of glycosaminoglycan-modified electrically conductive polymers for the first time, particularly highlighting the effect of the chosen dopant on material characteristics, such as surface morphology or stiffness, electrochemical properties, and consequently, cell-material interactions.

Chondroitin sulfate: are the purity and the structural features well assessed? A review on the analytical challenges

Animal origin chondroitin sulfate is employed as anti-inflammatory drug and food supplement against anti-osteoarthritis, but also as antioxidant, antitumor, anticoagulant, and immune-regulatory agent or as biomaterial in tissue engineering scaffolds and in drug-delivery systems. As its biological properties depend on the structural characteristics, multi-analytical approaches are necessary to correlate specific features of its heterogenic composition to the different bioactivities. This is of paramount importance to assess the efficacy of pharmaceuticals and food supplements, beyond safety quality control. This review would address the issue of chondroitin sulfate characterization according to the Pharmacopeia testing monograph point of view giving an update of the analytical novelties reported in the last ten years that might be employed for the product testing and releasing on the market. Not-instrumental (e.g. colorimetric assays) and instrumental techniques, most of them coupling diverse chromatographic separation methods with spectroscopic and spectrometry detection techniques, mono and bi-dimensional NMR approaches, are compared as tools to evaluate identity, titer, purity grade, monosaccharide and disaccharide composition, averaged molecular weight and viscosity, charge and sulfate content, impurities and related substances including the presence of other glycosaminoglycans.

Analytical Challenges and Metrological Approaches to Ensuring Dietary Supplement Quality: International Perspectives

The increased utilization of metrology resources and expanded application of its' approaches in the development of internationally agreed upon measurements can lay the basis for regulatory harmonization, support reproducible research, and advance scientific understanding, especially of dietary supplements and herbal medicines. Yet, metrology is often underappreciated and underutilized in dealing with the many challenges presented by these chemically complex preparations. This article discusses the utility of applying rigorous analytical techniques and adopting metrological principles more widely in studying dietary supplement products and ingredients, particularly medicinal plants and other botanicals. An assessment of current and emerging dietary supplement characterization methods is provided, including targeted and non-targeted techniques, as well as data analysis and evaluation approaches, with a focus on chemometrics, toxicity, dosage form performance, and data management. Quality assessment, statistical methods, and optimized methods for data management are also discussed. Case studies provide examples of applying metrological principles in thorough analytical characterization of supplement composition to clarify their health effects. A new frontier for metrology in dietary supplement science is described, including opportunities to improve methods for analysis and data management, development of relevant standards and good practices, and communication of these developments to researchers and analysts, as well as to regulatory and policy decision makers in the public and private sectors. The promotion of closer interactions between analytical, clinical, and pharmaceutical scientists who are involved in research and product development with metrologists who develop standards and methodological guidelines is critical to advance research on dietary supplement characterization and health effects.

Screening of the Chemical Composition and Identification of Hyaluronic Acid in Food Supplements by Fractionation and Fourier-Transform Infrared Spectroscopy

Hyaluronic acid, together with collagen, vitamins or plant extracts, is a part of many cosmetic and food preparations. For example, this polysaccharide is used in formulation of many food supplements due to its protective effects on human health. In this work, the screening of the chemical composition of three chosen dietary supplements (powder, tablets and capsules) containing hyaluronic acid was carried out using Fourier-transform infrared spectroscopy. Because of the low amount of analyte in all these samples, it was isolated or concentrated prior to the analysis using a suitable sequential fractionation protocol. Individual isolation procedures were established for each sample based on their declared composition. Firstly, the major components such as collagen or vitamins were removed to obtain polysaccharide fractions by the enzymatic treatment and/or washing out with the appropriate solvents. In some cases, the water insoluble part was removed from the rest dissolved in water. Then, hyaluronic acid was precipitated with copper(II) cations and thus separated from the other polysaccharides. Finally, the analyte was identified in the enriched fractions by the characteristic vibrational bands. The amount of hyaluronic acid in the purified fractions was determined in three ways: gravimetrically, spectrophotometrically, and using isotachophoresis. The combination of the appropriate preparative and analytical steps led to the successful evaluation of chemical composition, finding and quantification of hyaluronic acid in all the studied samples.

Handheld laser-induced fluorescence detection systems with different optical configurations

There is a growing urgent requirement for miniaturized laser-induced fluorescence (LIF) detection systems in many research fields. In this work, miniaturized LIF detectors with three different optical configurations of orthogonal, confocal, and oblique were developed, using a laser diode as the excitation source and a photodiode as the photodetector. The computer simulation and experimental methods were used to investigate the distributions of laser scattered light and fluorescent light near the detection window. Other conditions including the solution preparation, sample flow rate, alignment method and filter model were also optimized. Under the optimized conditions, the detection limits of sodium fluorescein for orthogonal and confocal LIF detectors were 40 pM and 50 pM, respectively, while the limit of detection (LOD) for oblique LIF detector were 1 nM (45°) and 7 nM (67.5°). We further built a fully integrated handheld orthogonal LIF detector with a total size of 50 × 20 × 46 mm³, a cost of $380, and a detection limit of 10 pM for sodium fluorescein. It is expected that such a LIF detector could be applied in field analysis as a portable instrument or in other analysis systems as a detection module.

Chondroitin Sulfate in USA Dietary Supplements in Comparison to Pharma Grade Products: Analytical Fingerprint and Potential Anti-Inflammatory Effect on Human Osteoartritic Chondrocytes and Synoviocytes

The biological activity of chondroitin sulfate (CS) and glucosamine (GlcN) food supplements (FS), sold in USA against osteoarthritis, might depend on the effective CS and GlcN contents and on the CS structural characteristics. In this paper three USA FS were compared to two pharmaceutical products (Ph). Analyses performed by HPAE-PAD, by HPCE and by SEC-TDA revealed that the CS and GlcN titers were up to −68.8% lower than the contents declared on the labels and that CS of mixed animal origin and variable molecular weights was present together with undesired keratan sulfate. Simulated gastric and intestinal digestions were performed in vitro to evaluate the real CS amount that may reach the gut as biopolymer. Chondrocytes and synoviocytes primary cells derived from human pathological joints were used to assess: cell viability, modulation of the NF-κB, quantification of cartilage oligomeric matrix protein (COMP-2), hyaluronate synthase enzyme (HAS-1), pentraxin (PTX-3) and the secreted IL-6 and IL-8 to assess inflammation. Of the three FS tested only one (US FS1) enhanced chondrocytes viability, while all of them supported synoviocytes growth. Although US FS1 proved to be less effective than Ph as it reduced NF-kB, it could not down-regulate COMP-2; HAS-1 was up-regulated but with a lower efficacy. Inflammatory cytokines were markedly reduced by Ph while a slight decrease was only found for US-FS1.