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Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible biopolymers. These biomaterials have grown in importance in the fields of tissue engineering and tissue reconstruction for structural applications where tissue morphology is critical, such as bone, cartilage, blood vessels, and skin, among others. Furthermore, they can be used to accelerate the regeneration in combination with drugs, as drug delivery systems, thus reducing microbial infections. When cells are cultured under stress conditions, a wide variety of microorganisms produce them as a store of intracellular energy in the form of homo- and copolymers of [R]—hydroxyalkanoic acids, depending on the carbon source used for microorganism growth. This paper gives an overview of PHAs, their biosynthetic pathways, producing microorganisms, cultivation bioprocess, isolation, purification and characterization to obtain biomaterials with medical applications such as tissue engineering.

Surface Acoustic Wave (SAW) sensors with several types of polymer sensing films, containing embedded Fe3O4 nanoparticles (NPs) with various dimensions and concentrations, were studied. A sensor with a sensing film consisting of the polymer alone was used for comparison. NPs with a mean diameter of 7 nm were produced by laser ablation with 5 ns pulse durations, and NPs with 13 nm diameters were obtained with a laser having 10 ps pulse durations. The properties of the Surface Acoustic Wave sensors with such sensing films were analyzed. Their response (frequency shift, sensitivity, noise and response time) to three different volatile organic components (VOCs) at various concentrations were compared with one another. The frequency shift and sensitivity increased with increasing NP concentration in the polymer for a given NP dimension and with decreasing NP diameter for a given concentration. The best results were obtained for the smallest NPs used. The SAW sensor containing 7 nm NPs had a limit of detection (LOD) of 65 ppm (almost five times better than the sensor with polymer alone), and a response time of about 9 s for ethanol.

The effect of nanostructure of PLD (Pulsed Laser Deposition)-deposited Pd/WO3 sensing films on room temperature (RT) hydrogen sensing properties of SAW (Surface Acoustic Wave) sensors was studied. WO3 thin films with different morphologies and crystalline structures were obtained for different substrate temperatures and oxygen deposition pressures. Nanoporous films are obtained at high deposition pressures regardless of the substrate temperature. At lower pressures, high temperatures lead to WO3 c-axis nanocolumnar growth, which promotes the diffusion of hydrogen but only once H2 has been dissociated in the nanoporous Pd layer. XRD (X-ray Diffraction) analysis indicates texturing of the WO3 layer not only in the case of columnar growth but for other deposition conditions as well. However, it is only the predominantly c-axis growth that influences film sensing properties. Bilayers consisting of nanoporous Pd layers deposited on top of such WO3 layers lead to good sensing results at RT. RT sensitivities of 0.12–0.13 Hz/ppm to hydrogen are attained for nanoporous bilayer Pd/WO3 films and of 0.1 Hz/ppm for bilayer films with a nanocolumnar WO3 structure. SAW sensors based on such layers compare favorably with WO3-based hydrogen detectors, which use other sensing methods, and with SAW sensors with dense Pd/WO3 bilayers.

Biomaterials represent a distinct class of materials used in various medical applications, such as replicating the shape or function of damaged tissue caused by disease or trauma. The increasing focus on polyhydroxyalkanoate (PHA) research can be attributed to their properties, such as biodegradability, biocompatibility, and bioresorbability. PHAs can be incorporated into polymeric complexes or combined with bioceramics or bioactive substances. Films of PHO-HAp-Curcumin were prepared, and optimization studies were conducted using Design-Expert software (Stat-Ease 360-Trial Version). The effects of independent variables (amount of PHO, HAp, and curcumin) on biodegradability, film thickness, and curcumin release were studied. Statistical modeling revealed significant interactions among the components, with the 2FI and quadratic models providing strong predictive accuracy. The interaction of HAp and PHO amounts (X2X3) has a significant effect on biodegradability (Y1) and film thickness (Y3). For the degree of the cumulative release of curcumin (CDR), there was no significant interaction between the independent variables (curcumin-X1, HAp-X2, and PHO-X3). Optimized film exhibited a maximum desirability of 0.777 with 1 mg of curcumin, 100 mg of HAp, and 172.31 mg of PHO. A morphological analysis of optimized film revealed a rough, particle-rich surface favorable for biomedical use. The findings highlight the promise of PHO-HAp-Curcumin composite films in advancing tissue engineering.

This study investigates the fabrication and characterization of polymeric nanoparticles based on polyhydroxyalkanoates (PHAs) loaded with curcumin for biomedical applications. PHAs, biodegradable and biocompatible polymers, were synthesized via bacterial fermentation and used to encapsulate curcumin using the nanoprecipitation method. The resulting nanoparticles were characterized for their particle size, polydispersity index, and encapsulation efficiency, achieving high entrapment rates (above 80%) and nanometric size distribution. Stability assessments demonstrated prolonged structural integrity under storage conditions. In vitro release studies conducted in phosphate-buffered saline at pH 5 and 7.4 revealed sustained drug release profiles. Biocompatibility and cytotoxicity assays using human astrocytes and fibroblasts confirmed the nanoparticles’ safety, while antiproliferative tests on glioblastoma and colon cancer cell lines indicated potential therapeutic efficacy. Additionally, skin irritation and corrosion tests using the EpiDerm™ model classified the formulations as non-irritant and non-corrosive. These findings suggest that PHA-based nanoparticles offer a promising nanocarrier system for curcumin delivery, with potential applications in cancer treatment and regenerative medicine. Future research should focus on optimizing the formulation and evaluating in vivo therapeutic effects.

Laser-deposited gold immobilization layers with different porosities were incorporated into Love Wave Surface Acoustic Wave sensors (LW-SAWs). Acetylcholinesterase (AChE) enzyme was immobilized onto three gold interfaces with different morphologies, and the sensor response to chloroform was measured. The response of the sensors to various chloroform concentrations indicates that their sensing properties (sensitivity, limit of detection) are considerably improved when the gold layers are porous, in comparison to a conventional dense gold layer. The results obtained can be used to improve properties of SAW-based biosensors by controlling the nanostructure of the gold immobilization layer, in combination with other enzymes and proteins, since the design of the present sensor is the same as that for a Love Wave biosensor.

The paper aims at the synthesis and characterization of a wollastonite ceramic layer (belonging to the CaO-SiO 2 system) deposited by PLD (pulsed laser deposition) method on a titanium metal substrate, in order to improve titanium biocompatibility and bioactivity. The silicate precursor mixture was synthesized by the sol–gel method. From this precursor was obtained the ceramic target by sintering at 1150 °C for 6 h. The obtained films on the titanium metal substrate were characterized by x-ray diffraction, scanning microscopy and by determination of the contact angle. Also, the materials were tested in vitro to determine the bioactivity and biocompatibility of thin films. The obtained results indicate the presence of wollastonite in films composition and a good bioactivity in the presence of cells, which suggests that this type of thin films is suitable for medical implants.

Helichrysum arenarium (L.) Moench, belonging to the Asteraceae family, is known in traditional medicine for its diuretic, choleretic, and anti-inflammatory properties. This review focuses on the superiority of Helichrysum arenarium (sandy everlasting) over other known plants as a source of active pharmacological compounds used in complementary medicine to prevent digestive and hepatobiliary illnesses. Because the species exists both in spontaneous flora and in crops, this article highlights the development of a controlled culture of H. arenarium, following the reproducible quality of the plant as a biological material. The diversity of phytocompounds, especially well-characterized flavonoid extracts, and the differences between extraction procedures are discussed. Antiviral, antibacterial, and antifungal activities against human pathogens proved by different plant extracts and their mechanisms of action are analyzed. This study aims to contribute to the insufficient knowledge regarding the effects of Helichrysum species and to reveal that their extracts can be a valuable source for new active pharmaceutical ingredients.

Laser deposition was used to obtain Pd/ZnO bilayers, which were used as sensing layers in surface acoustic wave (SAW) sensors. The effect of laser deposition parameters such as deposition pressure, laser energy per pulse, laser wavelength or pulse duration on the porosity of the Pd and ZnO films used in the sensors was studied. The effect of the morphology of the Pd and ZnO components on the sensor response to hydrogen was assessed. Deposition conditions producing more porous films lead to a larger sensor response. The morphology of the ZnO component of the bilayer is decisive and has an influence on the sensor properties in the same order of magnitude as the use of a bilayer instead of a single Pd or ZnO layer. The effect of the Pd film morphology is considerably smaller than that of ZnO, probably due to its smaller thickness. This has implications in other bilayer material combinations used in such sensors and for other types of analytes.

A Surface Acoustic Wave (SAW) hydrogen sensor with a Pd/ZnO bilayer structure for room temperature sensing operation has been obtained by Pulsed Laser Deposition (PLD). The sensor structure combines a Pd layer with optimized porosity for maximizing mass effects, with the large acoustoelectric effect at the Pd/ZnO interface. The large acoustoelectric effect is due to the fact that ZnO has a surface conductivity which is highly sensitive to chemisorbed gases. The sensitivity of the sensor was determined for hydrogen concentrations between 0.2% and 2%. The limit of detection (LOD) of the bilayer sensor was about 4.5 times better than the single ZnO films and almost twice better than single Pd films.