Physicochemical and Biological Characterisation of Diclofenac Oligomeric Poly(3-hydroxyoctanoate) Hybrids as β-TCP Ceramics Modifiers for Bone Tissue Regeneration

Development of Glutathione Hydrogel Carriers Containing Zinc Oxide Microparticles for Skin Regeneration Processes

Skin represents the largest organ in the human body, functioning as a protective barrier against environmental factors while playing a critical role in thermoregulation. Acne vulgaris is recognized as the most common dermatological condition affecting adolescents, and if left untreated, it can result in lasting skin damage and associated psychosocial challenges. This study aims to develop innovative polymeric biomaterials that could effectively support the treatment of acne vulgaris. The synthesis of these biomaterials involves the use of polyethylene glycol 6000, sodium alginate, and the antioxidant protein glutathione (GHS) to create polymeric hydrogels. These hydrogels were generated via a UV-mediated crosslinking process. To enhance the functional properties of the hydrogels, zinc oxide microparticles (ZnO), synthesized through a wet precipitation method, were incorporated into the formulations. Characterization of the ZnO was performed using Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), particle sizer analysis, and Scanning Electron Microscopy (SEM). Additionally, the bioactivity of the synthesized materials was evaluated through incubation in media simulating physiological body fluids. The cytotoxic effects of the biomaterials were assessed using an indirect test on mouse fibroblast (L929) cells, in accordance with ISO 10993-5 guidelines. The results of our research indicate that the developed biomaterials exhibit potential as a carrier for active substances, contributing positively to the treatment of acne vulgaris and potentially improving overall skin health.

Novel Biodegradable Nanoparticulate Chain-End Functionalized Polyhydroxybutyrate-Caffeic Acid with Multifunctionalities for Active Food Coatings

The bioactivities of polyhydroxyalkanoates have been curtailed owing to the lack of bioactive functional groups in their backbones. In this regard, polyhydroxybutyrate (PHB) produced from new locally isolated Bacillus nealsonii ICRI16 was chemically modified for enhancing its functionality, stability as well as solubility. First, PHB was transformed to PHB-diethanolamine (PHB-DEA) by transamination. Subsequently, for the first time, the chain ends of the polymer were substituted by caffeic acid molecules (CafA), generating novel PHB-DEA-CafA. The chemical structure of such a polymer was confirmed by Fourier-transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (¹H NMR). The modified polyester demonstrated improved thermal behavior compared to PHB-DEA as was shown by thermogravimetric analysis, derivative thermogravimetry, and differential scanning calorimetry analyses. Interestingly, 65% of PHB-DEA-CafA was biodegraded in a clay soil environment after 60 days at 25 °C, while 50% of PHB was degraded within the same period. On another avenue, PHB-DEA-CafA nanoparticles (NPs) were successfully prepared with an impressive mean particle size of 223 ± 0.12 nm and high colloidal stability. The nanoparticulate polyester had powerful antioxidant capacity with an IC₅₀ of 32.2 mg/mL, which was the result of CafA loading in the polymer chain. More importantly, the NPs had a considerable effect on the bacterial behavior of four food pathogens, inhibiting 98 ± 0.12% of Listeria monocytogenes DSM 19094 after 48 h of exposure. Finally, the raw polish sausage coated with NPs had a significantly lower bacterial count of 2.11 ± 0.21 log cfu/g in comparison to other groups. When all these positive features are recognized, the polyester described herein could be considered as a good candidate for commercial active food coatings.

Hydrothermal vs microwave nanoarchitechtonics of carbon dots significantly affects the structure, physicochemical properties, and anti-cancer activity against a specific neuroblastoma cell line

Carbon dots (CDs) from glucose were synthesized using two of the most common bottom-up methods, namely, microwave assisted (MW) and hydrothermal carbonization (HT). Synthetic parameters such as reaction time, temperature, and precursor concentration were changed to study the effects of each parameter on CD size, structure, surface functionalities, charge, photoluminescence behavior, quantum yield, cytotoxicity, blood-brain barrier (BBB) crossing ability and bioimaging. A detailed analysis is performed to compare the structure and properties of the CDs synthesized in ten different conditions. We show that the synthesis route drastically changes the structure, properties, and related functions of glucose-derived CDs yielding two different subtypes of CDs. Surprisingly, CDs that was synthesized via HT method showed specific anticancer activity against a neuroblastoma cell line while being non-toxic towards healthy cell lines, indicating significant potential for therapeutic applications. CDs synthesized via MW crosses the BBB in zebrafish and rat models, and accumulates in neurons. CDs synthesized via MW method showed high biocompatibility and a great potential to be used for bioimaging applications in vitro and in vivo targeting neurons. Finally, a formation mechanism of CDs is proposed for both HT and MW synthesis routes.

The Influence of Novel, Biocompatible, and Bioresorbable Poly(3-hydroxyoctanoate) Dressings on Wound Healing in Mice

The human body's natural protective barrier, the skin, is exposed daily to minor or major mechanical trauma, which can compromise its integrity. Therefore, the search for new dressing materials that can offer new functionalisation is fully justified. In this work, the development of two new types of dressings based on poly(3-hydroxyoctanoate) (P(3HO)) is presented. One of the groups was supplemented with conjugates of an anti-inflammatory substance (diclofenac) that was covalently linked to oligomers of hydroxycarboxylic acids (Oli-dicP(3HO)). The novel dressings were prepared using the solvent casting/particulate leaching technique. To our knowledge, this is the first paper in which P(3HO)-based dressings were used in mice wound treatment. The results of our research confirm that dressings based on P(3HO) are safe, do not induce an inflammatory response, reduce the expression of pro-inflammatory cytokines, provide adequate wound moisture, support angiogenesis, and, thanks to their hydrophobic characteristics, provide an ideal protective barrier. Newly designed dressings containing Oli-dicP(3HO) can promote tissue regeneration by partially reducing the inflammation at the injury site. To conclude, the presented materials might be potential candidates as excellent dressings for wound treatment.

Review of the Developments of Bacterial Medium-Chain-Length Polyhydroxyalkanoates (mcl-PHAs)

Synthetic plastics derived from fossil fuels—such as polyethylene, polypropylene, polyvinyl chloride, and polystyrene—are non-degradable. A large amount of plastic waste enters landfills and pollutes the environment. Hence, there is an urgent need to produce biodegradable plastics such as polyhydroxyalkanoates (PHAs). PHAs have garnered increasing interest as replaceable materials to conventional plastics due to their broad applicability in various purposes such as food packaging, agriculture, tissue-engineering scaffolds, and drug delivery. Based on the chain length of 3-hydroxyalkanoate repeat units, there are three types PHAs, i.e., short-chain-length (scl-PHAs, 4 to 5 carbon atoms), medium-chain-length (mcl-PHAs, 6 to 14 carbon atoms), and long-chain-length (lcl-PHAs, more than 14 carbon atoms). Previous reviews discussed the recent developments in scl-PHAs, but there are limited reviews specifically focused on the developments of mcl-PHAs. Hence, this review focused on the mcl-PHA production, using various carbon (organic/inorganic) sources and at different operation modes (continuous, batch, fed-batch, and high-cell density). This review also focused on recent developments on extraction methods of mcl-PHAs (solvent, non-solvent, enzymatic, ultrasound); physical/thermal properties (Mw, Mn, PDI, Tm, Tg, and crystallinity); applications in various fields; and their production at pilot and industrial scales in Asia, Europe, North America, and South America.

Post-Synthetic Enzymatic and Chemical Modifications for Novel Sustainable Polyesters

Because of their biodegradability, compostability, compatibility and flexible structures, biodegradable polymers such as polyhydroxyalkanoates (PHA) are an important class of biopolymers with various industrial and biological uses. PHAs are thermoplastic polyesters with a limited processability due to their low heat resistance. Furthermore, due to their high crystallinity, some PHAs are stiff and brittle. These features result sometimes in very poor mechanical characteristics with low extension at break values which limit the application range of some natural PHAs. Several in vivo approaches for PHA copolymer modifications range from polymer production to enhance PHA-based material performance after synthesis. The methods for enzymatic and chemical polymer modifications are aiming at modifying the structures of the polyesters and thereby their characteristics while retaining the biodegradability. This survey illustrates the efficient use of enzymes and chemicals in post-synthetic PHA modifications, offering insights on these green techniques for modifying and improving polymer performance. Important studies in this sector will be reviewed, as well as chances and obstacles for their stability and hyper-production.

Controlled Delivery of Pan-PAD-Inhibitor Cl-Amidine Using Poly(3-Hydroxybutyrate) Microspheres

This study deals with the process of optimization and synthesis of Poly(3-hydroxybutyrate) microspheres with encapsulated Cl-amidine. Cl-amidine is an inhibitor of peptidylarginine deiminases (PADs), a group of calcium-dependent enzymes, which play critical roles in a number of pathologies, including autoimmune and neurodegenerative diseases, as well as cancer. While Cl-amidine application has been assessed in a number of in vitro and in vivo models; methods of controlled release delivery remain to be investigated. P(3HB) microspheres have proven to be an effective delivery system for several compounds applied in antimicrobial, wound healing, cancer, and cardiovascular and regenerative disease models. In the current study, P(3HB) microspheres with encapsulated Cl-amidine were produced in a size ranging from ~4–5 µm and characterized for surface morphology, porosity, hydrophobicity and protein adsorption, in comparison with empty P(3HB) microspheres. Cl-amidine encapsulation in P(3HB) microspheres was optimized, and these were found to be less hydrophobic, compared with the empty microspheres, and subsequently adsorbed a lower amount of protein on their surface. The release kinetics of Cl-amidine from the microspheres were assessed in vitro and expressed as a function of encapsulation efficiency. There was a burst release of ~50% Cl-amidine in the first 24 h and a zero order release from that point up to 16 days, at which time point ~93% of the drug had been released. As Cl-amidine has been associated with anti-cancer effects, the Cl-amidine encapsulated microspheres were assessed for the inhibition of vascular endothelial growth factor (VEGF) expression in the mammalian breast cancer cell line SK-BR-3, including in the presence of the anti-proliferative drug rapamycin. The cytotoxicity of the combinatorial effect of rapamycin with Cl-amidine encapsulated P(3HB) microspheres was found to be 3.5% more effective within a 24 h period. The cells treated with Cl-amidine encapsulated microspheres alone, were found to have 36.5% reduction in VEGF expression when compared with untreated SK-BR-3 cells. This indicates that controlled release of Cl-amidine from P(3HB) microspheres may be effective in anti-cancer treatment, including in synergy with chemotherapeutic agents. Using controlled drug-delivery of Cl-amidine encapsulated in Poly(3-hydroxybutyrate) microspheres may be a promising novel strategy for application in PAD-associated pathologies.

Polyhydroxyalkanoates, bacterially synthesized polymers, as a source of chemical compounds for the synthesis of advanced materials and bioactive molecules

Research into polyhydroxyalkanoates (PHAs) is growing exponentially. These bacterially derived polyesters offer a spectrum of possible applications, such as in manufacturing of daily-use objects, production of medical devices and implantable objects, or as synthons in chemical and pharmaceutical industries. Thanks to their broad physicochemical features, PHAs can be seen as polymers of the future, which can replace traditional petrochemical equivalents. As they are synthesized by bacteria through fermentation processes, these polyesters can be obtained from virtually any carbon source in a sustainable manner. Characterized by biodegradability and biocompatibility, they are used in many industries, ranging from production of everyday objects to medical applications. Furthermore, as they are built from bioactive monomers, namely (R)-3-hydroxyacids, they provide a platform for the synthesis of advanced chemical compounds. In this mini review, the reader will be acquainted with recent studies conducted at the Jerzy Haber Institute of Catalysis and Surface Chemistry of the Polish Academy of Sciences in collaboration with other groups that have contributed to the development of PHA-based medical materials, bioactive molecules and novel green solvents derived from PHA monomers.Key points• Polyhydroxyalkanoates are emerging polymers for biomedical applications• Polyhydroxyalkanoates can be modified easily to provide novel materials• (R)-3-Hydroxyacids are good synthons for bioactive substances and green solvents.