Microparticles (MPs) with controlled morphologies and sizes have been investigated by several researchers due to their importance in pharmaceutical, ceramic, cosmetic, and food industries to just name a few. In particular, the electrospray (ES) technique has been shown to be a viable alternative for the development of single particles with different dimensions, multiple layers, and varied morphologies. In order to adjust these properties, it is necessary to optimize different experimental parameters, such as polymer solvent, voltage, flow rate (FR), type of collectors, and distance between the collector and needle tip, which will all be highlighted in this review. Moreover, the influence and contributions of each of these parameters on the design and fabrication of polymeric MPs are described. In addition, the most common configurations of ES systems for this purpose are discussed, for instance, the main configuration of an ES system with monoaxial, coaxial, triaxial, and multi-capillary delivery. Finally, the main types of collectors employed, types of synthesized MPs and their applications specifically in the pharmaceutical and biomedical fields will be emphasized. To date, ES is a promising and versatile technology with numerous excellent applications in the pharmaceutical and biomaterials field and such MPs generated should be employed for the improved treatment of cancer, healing of bone, and other persistent medical problems.

CaWO 4 nanocrystals were synthesized by the coprecipitation method of with different solvent ratio (water/ethylene glycol)

Osteoporosis is a public health problem, with bone loss being the main consequence. Hydroxyapatite (HA) has been largely used as a bioceramic to stimulate bone growth. In our work, a cerium-containing HA (Ce-HA) has been proposed and its effects on the antimicrobial and bone-inducing properties were investigated. The synthesis of the materials occurred by the suspension–precipitation method (SPM). The XRD (X-ray Diffraction) confirmed the crystalline phase, and the Rietveld refinement confirmed the crystallization of HA and Ce-HA in a hexagonal crystal structure in agreement with ICSD n° 26205. Characterizations by FT-IR (Fourier Transform Infrared Spectroscopy), XPS (X-ray Photoemission Spectroscopy), and FESEM-EDS (Field Emission Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) confirmed the presence of cerium (Ce3+ and Ce4+). The antibacterial activity of Has was evaluated against Staphylococcus aureus 25,923 and Escherichia coli 25,922 strains, which revealed that the material has antimicrobial properties and the cytotoxicity assay indicated that Ce-containing HA was classified as non-toxic. The effects of Ce-HA on bone repair, after application in bone defects in the tibia of female rats with osteoporosis induced by ovariectomy (OVX), were evaluated. After 15 and 30 days of implantation, the samples were analyzed by Raman, histology and X-ray microtomography. The results showed that the animals that had the induced bone defects filled with the Ce-HA materials had more expressive bone neoformation than the control group.

Hydroxyapatite (HAp) is a ceramic material composing the inorganic portion of bones. Ionic substitutions enhance characteristics of HAp, for example, calcium ions (Ca2+) by cerium ions (Ce3+). The use of HAp is potentialized through biopolymers, cashew gum (CG), and gellan gum (GG), since CG/GG is structuring agents in the modeling of structured biocomposites, scaffolds. Ce-HApCG biocomposite was synthesized using a chemical precipitation method. The obtained material was frozen (–20 °C for 24 h), and then vacuum dried for 24 h. The Ce-HApCG was characterized by X-Ray diffractograms (XRD), X-ray photoemission spectra (XPS), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy (EDS). XRD and FTIR showed that Ce-HApCG was successfully synthesized. XRD showed characteristic peaks at 2θ = 25.87 and 32.05, corresponding to the crystalline planes (0 0 2) and (2 1 1), respectively, while phosphate bands were present at 1050 cm−1 and 1098 cm−1, indicating the success of composite synthesis. FESEM showed pores and incorporated nanostructured granules of Ce-HApCG. The mechanical test identified that Ce-HApCG has a compressive strength similar to the cancellous bone’s strength and some allografts used in surgical procedures. In vitro tests (MTT assay and hemolysis) showed that scaffold was non-toxic and exhibited low hemolytic activity. Thus, the Ce-HApCG has potential for application in bone tissue engineering.

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Bacterial cellulose (BC) is a nanofibrous biomaterial biosynthetized by a series of acetic bacteria with unique properties with application in many tissue engineering purposes. Calcium phosphates (CPs), mainly hydroxyapatite, are bioceramics that possess similar composition of host bones and are able to stimulate osteoconduction and osteointegration to living tissues. Bacterial cellulose-calcium phosphates composites have caught the attention of researchers by their excellent mechanical properties and biocompatibility, being considered an excellent proposal to development of new synthetic grafts to bone tissue engineering. The minireview presented here focuses on various fabrication methods used to prepare and novel applications of BC-CPs composites and their applications in BTE.Keywords:

The development of photocatalystsor their modification to obtain new photocatalytic performances for the removal of contaminants is a challenge. Hydroxyapatite (HAp), (Ca10(PO4)6(OH)2), is an inorganic component with a high superficial area and low toxicity and the presence of metal in its structure can be an interesting strategy for the photocatalytic approach. This work aimed to synthesize gallium-containing HAp (Ga-HAp) as a promising material for photocatalytic performance. The synthesis was performed by the suspension–precipitation method. The material was characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Morphological analysis employed field emission scanning electron microscope (FESEM) and the elemental analysis by energy-dispersive spectroscopy (EDS). To evaluate the photocatalytic activity, methylene blue (MB) dye was used as a pollutant model under UV light for 120 min. The influence of Ga-HAp concentration (0.25, 0.50, and 1.00 g·L−1) and kinetic reaction was also studied. The Ga-HAp was successfully obtained by the suspension–precipitation method. The structural characterization by XRD and FESEM-EDS elucidated the presence of gallium in the structure of hydroxyapatite. The XPS results indicated the substitution of gallium in the crystal lattice of the material. The discoloration rate of MB dye using Ga-Hap was calculated by pseudo first-order kinetics, and the best rate constant was 7.5 × 10−3 min−1 using 1.00 g·L−1 of photocatalyst. The concentration of Ga-HAp influenced the photocatalytic process, because the discoloration rate increased as a function of the concentration of material. Therefore, Ga-HAp is a promising material for environmental remediation.

To produce polysaccharide-based hydrogels and cerium (Ce3+) doped hydroxyapatite plus chitosan and collagen to enable future applications in the treatment of joint degeneration. Hydrogel production and characterization were performed with Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis (TGA) and cytotoxicity testing with MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]. A final biomaterial composition was Kelcogel® Gelana (58%), chitosan (22.3%), Ce3+ doped hydroxyapatite (10.7%) and bovine collagen (9%), or selected aspect material gelatinous physical color with whitish color and can be injected. The biomaterial composition was proven in the FTIR and TGA, which also provided the maximum supported temperature. In the MTT assay, despite the reduction in viability of the experimental group compared to the control group, cell viability remained approximately 90%. In the FTIR and TGA tests, the material composition was proven. The material does not present cytotoxic behavior for the MTT test, being an alternative for the treatment of joint diseases.