Calcium Phosphate Research Articles

Genetic and biochemical determinants in potentially toxic metals resistance and plant growth promotion in Rhizobium sp LBMP-C04.

The association of bacteria resistant to potentially toxic metals (PTMs) with plants to remove, transfer, or stabilize these elements from the soil is an appropriate tool for phytoremediation processes in metal-contaminated environments. The objective of this study was to evaluate the potential ofRhizobiumsp. LBMP-C04 forphytoremediation processes and plant growth promotion in metal-contaminated soils. Functional annotation allowed us to predict a variety of genes related to PTMs resistance and plant growth promotion in the bacterial genome. Resistance genes are mainly associated with DNA repair, and the import or export of metals in bacterial cells to maintain cell homeostasis. Genes that promote plant growth are related to mechanisms of osmotic stress tolerance, phosphate solubilization, nitrogen metabolism, biological nitrogen fixation, biofilm formation, heat shock responses, indole-3-acetic acid (IAA) biosynthesis, tryptophan, and organic acids metabolism. Biochemical tests indicated thatRhizobiumsp. LBMP-C04 can solubilize calcium phosphate and produce siderophores and IAAin vitroin the presence of the PTMs Cd2+,Cu2+,Cr3+,Cr6+, Zn2+, and Ni2+. Results indicate the possibility of usingRhizobiumsp. LBMP-C04 as a potentially efficient bacterium in phytoremediation processesin environments contaminated by PTMs and simultaneously promote plant growth.

The effect of Trichoderma asperellum with reduced rates of inorganic fertilizer for growth and yield of carrot

This study was aimed to use Sri Lankan isolate Trichoderma asperellum in combination with reduced rates of chemical fertilizers to evaluate their efficiency as biofertilizer for the growth and yield characters of carrot. Inorganic phosphate sources like Eppawala rock Phosphate (ERP), Tri Calcium Phosphate (Ca3(PO4)2), Ferric Phosphate (FePO4) and Aluminum phosphate (AlPO4) solubilizing capacity of the isolate was estimated by using qualitative and quantitative methods. The pot experiment was carried out in Completely Randomized Design (CRD), consisting of six treatments and four replications. The Treatments were namely T1 (No Fertilizer), T2 (100% NPK - DOA Recommendation), T3 (50% P + N + K), T4 (50% P + Trichoderma asperellum + N + K), T5 (75% P + N +K) and T6 (75% P + Trichoderma asperellum + N + K). The results of qualitative estimation of Trichoderma asperellum exhibit good mycelial growth in the inorganic phosphate enriched media while the quantitative estimation results showed the variable potential of the Trichoderma asperellum to solubilize inorganic phosphates. According to the results of the pot experiment, significantly (P < 0.05) better results of growth and yield parameters were observed from treatments T6, T4 and T2. The results of the present study reveals that Sri Lankan isolate Trichoderma asperellum can be a growth and yield promoter and can be used as a biofertilizer to reduce the usage of costly and environmentally toxic inorganic fertilizer.

Structure and Morphogenetic Properties of Collagen Matrixes Obtained from Connective Tissue Sheaths of Paravertebral Tendons

The morphogenetic properties of a collagen gel prepared by acetic acid extraction from the tendon sheaths (peritenons) of the paravertebral tendons of Wistar rats were studied. The gel was used as a substrate during in vitro cultivation together with mesenchymal stromal cells for 14 days in the growth and osteogenic incubation media. It has been established that the collagen framework of the peritenon substrate is strengthened by increasing the connectivity of fibrillar nodes and is structured with the formation of lamellar and tangle formations. Sesamoid globules, penetrating into the substrate from the initial peritenon gel, during cultivation remain inert in the growth medium, but exhibit an increased ability to structure calcium phosphates in the osteogenic medium. The formation of cell-mediated structures occurs by directions of fibro-, tendo-, ligament- and osteogenic differentiation. The fibrogenic direction provides a structuring framework; the tenogenic direction – the formation of embryonic tendons according to the mechanism of lateral assembly of collagen subfibrils on cell surfaces and their autonomization in the form of tendon filament primordia; the ligamentogenic direction – structuring of collagen ribbons associated with tangles and elastic fibers; the osteogenic direction – the formation of lamellar, trabecular and nodular osteoid structures through intramembranous ossification, accompanied by activation of alkaline phosphatase and mineralization. The formation of enthesis predictors is the organization of commissures between mechanically different-phase components of osteoid structures and frame. A classification of taxonomic forms has been developed and a hypothesis has been proposed about the role of evolutionary tools in the structuring of the collagen framework in tissue cultures in vitro. The classification of taxonomic forms has been developed and a hypothesis has been proposed about the role of evolutionary tools in the structuring of the collagen framework in tissue cultures in vitro.

Real‐time measurement of heat stability of skim milk using attenuated total reflectance (ATR)‐FTIR spectroscopy

Milk proteins are susceptible to denaturation and aggregation upon heating, affecting product quality and shelf‐life. Understanding the underlying molecular changes during heating is important to the dairy industry for process optimisation and product functionality. This study used Attenuated Total Reflectance (ATR)‐Fourier Transform Infrared (FTIR) spectroscopy to non‐destructively measure changes in protein molecular structure as the precursor to heat‐induced aggregation in milk. Raw skim milk was divided into three subsamples, adjusted to pH 6.2, native pH or pH 7. Each sample was heated at 85°C on a BioATR crystal, with scans taken at 1‐min intervals over 20 min using FTIR to measure protein denaturation and aggregation. The second derivative of the amide I region was used to measure changes in protein structure, with the spectra for pH 6.2 samples changing faster than pH 6.8 or pH 7 samples, indicating a higher rate of denaturation. The peak at 1072 cm−1 related to colloidal calcium phosphate (CCP) increased with increasing temperature and pH. More extensive changes in CCP between colloidal and serum phases and protein denaturation/aggregation correlated with lower heat stability in milk. This study highlights the potential of ATR‐FTIR spectroscopy for assessing the heat stability of milk via in situ measurement of changes in protein structure and CCP.

Mesenchymal Stem Cell Plasticity: What Role Do Culture Conditions and Substrates Play in Shaping Biomechanical Signatures?

Cell functionality, driven by remarkable plasticity, is strongly influenced by mechanical forces that regulate mesenchymal stem cell (MSC) fate. This study explores the biomechanical properties of jaw periosteal cells (JPCs) and induced mesenchymal stem cells (iMSCs) under different culture conditions. We cultured both JPCs and iMSCs (n = 3) under normoxic and hypoxic environments, with and without osteogenic differentiation, and on laminin- or gelatin-coated substrates. Using atomic force microscopy, we measured cellular elasticity and Young’s modulus of calcium phosphate precipitates (CaPPs) formed under osteogenic conditions. Correlation analyses between cellular stiffness, quantity of CaPP deposition, and stiffness of formed CaPPs were evaluated. The results showed that iMSCs, despite their softer cellular consistency, tended to form CaPPs of higher elastic moduli than osteogenically differentiated JPCs. Particularly under normoxic conditions, JPCs formed stronger CaPPs with lower cellular stiffness profiles. Conversely, iMSCs cultivated under hypoxic conditions on laminin-coated surfaces produced stronger CaPPs while maintaining lower cellular stiffness. We conclude that JPCs and iMSCs display distinct biomechanical responses to culture conditions. While JPCs increase cellular stiffness during osteogenic differentiation, in particular under hypoxic conditions, iMSCs exhibit a decrease in stiffness, indicating a higher resistance to lower oxygen levels. In both cell types, a lower cellular stiffness profile correlates with enhanced mineralization, indicating that this biomechanical fingerprint serves as a critical marker for osteogenic differentiation.

Arginine-Loaded Nano-Calcium-Phosphate-Stabilized Lipiodol Pickering Emulsions Potentiates Transarterial Embolization-Immunotherapy.

Transarterial chemoembolization (TACE) continues to stand as a primary option for treating unresectable hepatocellular carcinoma (HCC). However, the increased tumor hypoxia and acidification will lead to the immunosuppressive tumor microenvironment (TME) featuring exhausted T cells, limiting the effectiveness of subsequent therapies following TACE. Herein, a stable water-in-oil lipiodol Pickering emulsion by employing calcium phosphate nanoparticles (CaP NPs) as stabilizers is developed and used to encapsulate L-arginine (L-Arg), which is known for its ability to modulate T-cell metabolism. The obtained L-Arg-loaded CaP-stabilized lipiodol Pickering emulsion (L-Arg@CaPL) with great emulsion stability can not only neutralize the tumor acidity via reaction of CaP NPs with protons but also enable the release of L-Arg, thereby synergistically promoting the reinvigoration of exhausted CD8+ T cells and effectively reversing tumor immunosuppression. As a result, TACE therapy with L-Arg@CaPL shows greatly improved therapeutic responses as demonstrated in an orthotopic liver tumor model in rats. This study highlights an effective yet simple nanoparticle-stabilized Pickering emulsion strategy to promote TACE therapy via modulation of the immunosuppressive TME, presenting great potential for clinical translation.

Topographic Evaluation of the Remineralizing Potential of Biomimetic Scaffolds on Enamel White Spot Lesions: An InVitro Study.

The modern approach to managing noncavitated white spot lesions (WSLs) emphasizes noninvasive strategies and biomimetic remineralization. Biomimetic scaffolds are designed to regenerate dental tissues rather than simply repair them. This study aimed to assess lesion depth, enamel structure, and the elemental composition of artificially induced WSLs after treatment with biomimetic remineralization techniques. Ninety-six freshly extracted anterior teeth, free from caries or enamel defects and extracted due to periodontal disease, were used. White spot lesions were induced on the labial surfaces, and the samples were divided into three groups based on the remineralizing agent: Group I, treated with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), which served as the positive control; Group II, treated with self-assembling peptide P11-4 (SAP-P11-4); and Group III, treated with phosphorylated nano-chitosan (Pchi-ACP). Enamel topography was analyzed at baseline and after treatment using polarized light microscopy, micro-Raman spectroscopy, and scanning electron microscopy. Statistical analysis was conducted using one-way ANOVA, Kruskal-Wallis, and Dunn's post hoc test (p = 0.05). The Kruskal-Wallis test indicated a significant difference in remineralization potential among the groups. Pchi-ACP showed the greatest reduction in lesion depth (62.65%), demonstrating significant subsurface enamel remineralization. This group also exhibited a smooth, regular enamel surface with shallow linear depressions. Elemental analysis confirmed successful calcium phosphate precipitation in Pchi-ACP, indicating a trend toward enamel regeneration. Pchi-ACP represents a promising biomimetic and minimally invasive approach for treating early WSLs, signifying a transition toward regenerative dentistry. (SAP-P11-4), while effective, was less successful than phosphorylated nano-chitosan but outperformed (CPP-ACP). Pchi-ACP demonstrates significant potential for minimally invasive treatment of early noncavitated carious lesions. By preserving natural tooth structure, this approach could greatly enhance oral health outcomes in the long term.

Synthesis and preclinical evaluation of a novel Oxy133-infused biomimetic bone graft using a rat model of posterolateral spinal fusion.

To (1) create a novel tissue-engineered bone graft comprising the osteoinductive oxysterol Oxy133 and (2) compare the osteogenic capability of this novel bone graft with bone graft substitutes previously examined. Oxy133 was homogeneously incorporated into a biomimetic bone graft substitute (BioMim) comprising extracellular matrix and calcium phosphates. Two iterations of the graft were created: one corresponding to an implant-dose of 2.0mg Oxy133 (BioMim-Oxy133-Lo) and the other corresponding to an implant-dose of 20mg Oxy133 (BioMim-Oxy133-Hi). Thirty-two male Sprague Dawley rats were allocated randomly to four equally sized groups: 1) BioMim-Oxy133-Lo, 2) BioMim-Oxy133-Hi, 3) absorbable collagen sponge (ACS) with topically applied Oxy133 dissolved in dimethyl sulfoxide (ACS-Oxy133; 20mg Oxy133/graft), and 4) ACS with topically applied rhBMP-2 dissolved in water (ACS-rhBMP-2; 5.0μg rhBMP-2/graft). All animals underwent L4-L5 posterolateral spinal fusion. Spines were harvested 8 weeks postoperatively and analyzed using micro-CT imaging. Successful fusion was achieved in all animals. Grafts containing Oxy133 had significantly greater bone volume, percentage bone volume (%BV), bone surface density (BSD), and trabecular number (TbN) compared to ACS-rhBMP-2 (p<0.01 for each). Animals treated with BioMim-Oxy133-Lo had the greatest %BV, BSD, and TbN (p<0.001 for each), whereas animals treated with ACS-rhBMP-2 had the lowest %BV, BSD, TbN, and trabecular thickness (p<0.001 for each). BioMim-Oxy133 is a novel bone graft that led to superior bone volume and quality compared to ACS-rhBMP-2 in a clinically translatable rat model of spinal fusion. Future work is needed to further evaluate this material as a safe and efficacious bone graft substitute.

Bioactive Properties of Phosphate-Modified Silicon Oxycarbide Protective Coatings: Morphology and Functional Evaluation.

This article presents a study on the functional properties and morphology of coatings based on amorphous silicon oxycarbide modified with phosphate ions and comodified with aluminum and boron. The objective of this modification was to enhance the biocompatibility and bioactivity without affecting its protective properties. The comodification was aimed toward stabilization of phosphate in the structure. The coatings were prepared according to the typical procedure for polymer-derived ceramics: synthesized via the sol-gel method, deposited using the dip-coating technique, and subsequently pyrolyzed. Comprehensive analyses of the morphology, surface properties, corrosion resistance, and bioactivity were conducted to assess their functional performance. The coatings exhibited uniform and smooth surfaces, with phase separation observed in the boron-modified SiBPOC series. Surface wettability and free energy measurements demonstrated that SiPOC and SiBPOC coatings possessed moderate hydrophilicity and favorable surface free energy for cell adhesion and bone tissue mineralization. Corrosion resistance tests in Ringer's solution revealed that SiBPOC coatings provided the highest protection against ion leaching, while SiAlPOC showed decreased resistance due to surface cracks. Bioactivity tests indicated calcium phosphate precipitation on the surface of all samples with higher hydroxyapatite formation on SiPOC and SiAlPOC coatings. In vitro tests using MG-63 osteoblast-like cells confirmed the biocompatibility of the coatings, with SiPOC and SiBPOC exhibiting the best combination of bioactivity, cell adhesion, and proliferation. These findings suggest that the phosphate- and boron-modified SiOC-based coatings are promising candidates for enhancing bone integration in orthopedic implants.

SIRT2 Mediated Microtubule Acetylation in Osteogenic Differentiation.

To assess the role of microtubule acetylation in the transportation of amorphous calcium phosphate (ACP)-containing vesicles that mediate the osteogenic differentiation process of rat bone mesenchymal stem cells (BMSCs). Rat BMSCs were cultured and transfected with sirtuin 2 (SIRT2) overexpression plasmids for an in vitro model. The microtubule acetylation-related protein levels were detected by western blots. The microtubule acetylation and the secretion rate of extracellular ACPcontaining vesicles were observed with immunofluorescence and live cell fluorescence imaging. The secretion of ACP was observed by transmission electron microscopy. The mineralised nodule formation was stained with Alizarin Red S staining and observed by microscopy. Microtubule acetylation was increased during osteogenic differentiation of BMSCs, and microtubule transport efficiency was enhanced. Mechanically, microtubule acetylation is the key reason for the increased transportation rate of ACP-containing vesicles and enhanced osteogenic differentiation, as both were blocked after SIRT2-mediated microtubule acetylation inhibition. Microtubule acetylation mainly promotes the transportation and secretion of ACP vesicles, and ultimately promotes the osteogenic differentiation process.

Highly efficient synthesis of pyrimidine-5-carbonitrile derivatives over a robust biowaste bone char-Bronsted solid acid catalyst

In this study, the conversion of bones (waste of food industry) into bone char is described. The presence of calcium phosphate and graphitic carbon gives bone char unique properties, with different possible uses. The catalytic behavior of bone char modified with chlorosulfonic acid is tested as reusable and eco-friendly solid acid biocatalyst in synthesis of pyrimidine-5-carbonitrile derivatives. The catalyst properties were characterized by different techniques such as FT-IR, BET, SEM, TEM, TGA, EDS and XRD. The bone char catalyst can be reused several times without reducing catalyst efficiency. In addition to the various reported benefits, the first use of bone char as a catalyst support for organic synthesis is an important novelty of this study.

Comparative Evaluation of Mathematical Model and In Vivo Study of Calcium Phosphate Bone Grafts

One of the key factors of the interaction ‘osteoplastic material—organism’ is the state of the implant surface. Taking into account the fact that the equilibrium in regeneration conditions is reached only after the reparative histogenesis process is completed, the implant surface is constantly modified. This work is devoted to the numerical description of the dynamic bilateral material–medium interaction under close to physiological conditions, as well as to the assessment of the comparability of the model with in vitro and in vivo experimental results. The semi-empirical model obtained on the basis of chemical kinetics allows us to describe numerically the processes occurring in the in vitro systems and extrapolates well to assess the behavior of dicalcium phosphate dihydrate (DCPD) material under conditions of ectopic (subcutaneous) implantation in Wistar rats. It is shown that an experiment conducted using a perfusion–diffusion bioreactor in a cell culture medium with the addition of fetal bovine serum (FBS) allows for achieving morphologically and chemically identical changes in the surface of the material in comparison with the real organism. This fact opens up wide possibilities for the creation of an analog of a ‘laboratory-on-a-chip’ and the transition from classical in vivo models to more controlled and mathematically based in vitro systems.

Enhanced biological activity of ACPs/cc/cs/PVA composite bone cement: a study on degradation, mineralization, and bone repair properties

The application of calcium phosphate cement in bone repair is often limited by its restricted degradation and mineralization capabilities. Here, we developed a novel composite material integrating amorphous calcium phosphates (ACPs) and calcium citrate (CC) to enhance biological activity. The composite was combined with powdered chitosan (CS) and liquid polyvinyl alcohol (PVA) to formulate the ACPs/CC/CS/PVA bone cement. We investigated the influence of varying PVA concentrations (0.3%, 0.6%, 1.0%, and 1.5%) on the cement’s setting time, hydrophilicity, compressive strength, pH, calcium release rate, and degradation rate. We find the ACPs/CC/CS/PVA bone cement demonstrates favorable injectability and anti-washout characteristics within the PVA concentration range of 0.3–1.5%. An elevated PVA concentration is correlated with enhanced anti-washout properties and improved compressive strength, reaching 42.8 MPa, which is essential for maintaining mechanical stability at the defect site. Additionally, the 1.5% PVA cement formulation ensures an adequate calcium ion concentration (6.5–9.5 mg/L) for the beginning of bone repair. Furthermore, in vivo animal studies have confirmed the biocompatibility of the ACPs/CC/CS/PVA bone cement. Controlled release of Ca2+ and PO4 3− ions from ACPs is suggested to facilitate osteoconduction and osteogenesis, highlighting the material’s prospect in bone repair applications.

Spatial confinement growth of high-performance persistent luminescence nanoparticles for image-guided sonodynamic therapy.

Near-infrared (NIR) persistent luminescence nanoparticles (PLNPs) have significant potential in diagnostic and therapeutic applications owing to their unique persistent luminescence (PersL). However, obtaining high-performance NIR PLNPs remains challenging because of the limitations of current synthesis methods. Herein, we introduce a spatial confinement growth strategy for synthesizing high-performance NIR PLNPs using hollow mesoporous silica (hmSiO2). By calcining precursor ions in the hollow cavity, the yolk size of NIR PLNPs was regulated, yielding well-dispersed Zn1.3Ga1.4Sn0.3O4: Cr0.005, Y0.003@hmSiO2 (ZS) with a yolk-shell structure. Compared to the conventional template method, ZS synthesized via the spatial confinement growth strategy exhibited a 7.7-fold increase in PersL intensity and a threefold increase in specific surface area. As a proof of concept, ZS@PpIX@CaP-AMD (ZPSC-AMD) nanoparticles, with potential for sonodynamic therapy (SDT), were synthesized by loading the sonosensitizer protoporphyrin IX (PpIX) into ZS, coating it with a calcium phosphate (CaP) shell, and modifying it with a tumor-targeting molecule plerixafor (AMD-3100). The tumor enrichment behavior of ZPSC-AMD was monitored by sensitive NIR PersL to guide SDT. Simultaneously, ZPSC-AMD enabled the precise monitoring of tumor accumulation, thereby guiding effective SDT. In addition, Ca2+ released from CaP degradation increased the level of reactive oxygen species during SDT, promoting tumor cell apoptosis. This study outlines a reliable design and synthesis approach for high-performance NIR PLNPs and promotes their development in biomedical applications. STATEMENT OF SIGNIFICANCE: The potential of near infrared (NIR) persistent luminescence nanoparticles (PLNPs) in bio applications is hindered by limitations in the synthesis method. In this article, we proposed a spatial confinement growth strategy of high-performance NIR PLNPs. The obtained PLNPs with yolk-shell structure showed a 7.7-fold increase in PersL intensity and a 3-fold increase in specific surface area, compared with the commonly used template method. Due to the advantages, sonodynamic therapeutic nanoparticles were constructed based on the above PLNPs, where persistent luminescence was used for ultrasensitive imaging to determine the optimal timing in sonodynamic therapy. In addition, the multifunctional calcium phosphate shell elevated the intracellular reactive oxygen species level to promote tumor cell apoptosis.

Review of &lt;i&gt;Siddha&lt;/i&gt; Marine Drug - &lt;i&gt;Muthuchippi&lt;/i&gt; (Pearl Oyster Shell) for Various Medicinal Properties

The Siddha system of medicine uses an opulent source of plants, metals, minerals, and marine and animal products for the preparation of medicine. The pearl oyster shell is a bivalve mollusc that lives in fresh and saltwater and generates pearls. The three major structural components of pearls are oblong, conchiolin, and calcium carbonate (CaCO3). Recently, interest in developing medications from marine materials has surged. In the fields of cancer, pain, and inflammation, many marine natural compounds are presently undergoing clinical trials. Pearl oyster shell, also known as Muthuchippi, is a key sea-derived medicine in the Siddha system of medicine. These shells include iron oxide, alumina, silica, calcium carbonate, phosphate, and sulfate of calcium and magnesium. Since it has been specially recommended to improve the strength, nutrition, and vitality of weak patients as well as for palpitations, digestion, heart tonic, and appetizer, pearl oysters are important in Siddha medicine. Traditionally, the calcined pearl oyster shell has been used to treat musculoskeletal diseases, anorectal diseases, respiratory diseases, and gastrointestinal diseases due to their high calcium carbonate content. This study aims to review several papers on the therapeutic potential of pearl oyster shells in treating various ailments. A comprehensive search of multiple databases, including PubMed and Google Scholar, yielded several papers for evaluation. According to this study, pearl oyster shells are utilized to cure a wide range of illnesses in all traditional Indian medical systems. Yet, there is scanty scientific data to support the efficacy of numerous indications. To substantiate this significant drug in the research forum, additional in-vitro and in-vivo studies must be carried out.

Lipid nanoparticles and transcranial focused ultrasound enhance the delivery of SOD1 antisense oligonucleotides to murine brain

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease with extremely limited therapeutic options. One key pathological feature of ALS is the abnormal accumulation of misfolded proteins within motor neurons. Hence, reducing the burden of misfolded protein has emerged as a promising therapeutic approach. Antisense oligonucleotides (ASOs) have the potential to effectively silence proteins with gain-of-function mutations, such as superoxide dismutase 1 (SOD1). However, ASO delivery to the central nervous system (CNS) is hindered by poor blood-brain barrier (BBB) penetration and the invasiveness of intrathecal administration. In the current study, we demonstrate effective systemic delivery of a next-generation SOD1 ASO (Tofersen) into the brain of wildtype and G93A-SOD1 transgenic C57BL/6 mice using calcium phosphate lipid nanoparticles (CaP lipid NPs). We show that transcranial focused ultrasound (FUS) with intravenously administered microbubbles can significantly enhance ASO-loaded nanoparticle delivery into the mouse brain. Magnetic resonance imaging (MRI) and immunohistological analysis showed reduced SOD1 expression in the FUS-exposed brain regions and increased motor neuron count in the spinal cord of treated mice suggesting decreased motor neuron degeneration. Importantly, the BBB opening was transient without evidence of structural changes, neuroinflammation or damage to the brain tissue, indicating that the treatment is well tolerated. Overall, our results highlight FUS-assisted nanoparticle delivery of ASOs as a promising non-invasive therapeutic strategy for the treatment of ALS and CNS diseases more broadly.

Enhancing the porosity of biphasic calcium phosphate using polyethylene glycol as the porogen for bone regeneration applications

Biphasic calcium phosphate (BCP) has been used as a material to support bone grafting, repair, recovery, and regeneration over the past decades. However, the inherent weakness of BCP is its low porosity, which limits the infiltration, differentiation, and proliferation of bone cells. To address this issue, porous BCP was synthesized using polyethylene glycol (PEG) 1000 with weight ratio ranging from 20%-60% in BCP as the porogen through the powder-forming method. Analytical methods such as Fourier transform infrared spectroscopy, x-ray diffraction, scanning electron microscopy were used to demonstrate the purity, morphology and functional groups on the material surface of the obtained BCP samples. Structurally, the BCP sample with 60% PEG, named B60, possessed the highest porosity of 71% and its pore diameters ranging from 5 to 75 µm. Besides, thein vitrobiocompatibility of B60 material have been demonstrated on the L929 cell line (90% cell viability) and simulated body fluid (apatite formation after 1 d). These results suggested that B60 should be further studied as a promising artificial material for bone regenerating applications.

A comparative evaluation of green surfactant-assisted calcium phosphate (CaP) coatings developed through electrodeposition and biomimetic routes

This study compares the properties of green surfactant-assisted calcium phosphate (CaP) coatings developed on 316L stainless steel (316L SS) substrates using electrodeposition (ED) and biomimetic (BM) methods. The influence of biosurfactants (BS) on these coatings' properties, deposited through both processes, is also investigated. X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FTIR) confirm the presence of brushite and hydroxyapatite (HAp) in the ED coatings, while BM coatings show only HAp without BS and both brushite and HAp phases with BS. The SEM analysis reveals distinct morphologies, with BS-assisted coatings showing more organized structures. The presence of BS results in more uniform coatings in both ED and BM methods. Atomic force microscopy (AFM) analysis indicates that BM coatings are smoother than ED coatings, and BS further reduces surface roughness. The comprehensive evaluations through nanoindentation, scratch testing, and corrosion studies reveal that BS-assisted ED coatings exhibit superior hardness (H), elastic modulus (E), adhesion strength, and corrosion resistance. Cytocompatibility studies using the MTT assay demonstrate that all coatings support cell attachment and proliferation without cytotoxic effects, with BM coatings showing slightly better cell viability. This study highlights the potential of green surfactant-assisted CaP coatings developed using ED and BM methods, for improving the biocompatibility and other biological properties of 316L SS implants.

Multifunctional alumina scaffolds with enhanced bioactivity and antimicrobial properties for bone tissue engineering

Inert ceramic implants suffer from significant complications such as lack of osseointegration, biofilm formation, and infections, necessitating the development of novel materials with both osteogenic and antibacterial properties to prevent implant failure. In this study, we aimed to multifunctionalize a tridimensional macroporous alumina scaffold with a biomimetic calcium phosphate (CaP) coating combined with a silver-based extra-thin film to enhance bioactivity and provide an additional antibacterial effect. The porous alumina scaffolds were fabricated through a powder metallurgy technique, followed by biomimetic deposition and DC magnetron sputtering. The coatings were characterized using SEM/EDS and AFM measurements to examine their morphology and topography. To evaluate the osteoconductive response of the materials, in vitro tests were conducted by immersing the samples in Simulated Body Fluid (SBF). The bioactivity tests revealed that the CaP-AgO coating, in line with the roughness surface and free surface energy values, exhibited a higher Ca/P ratio formation. This indicated an increased affinity for apatite adhesion, ultimately leading to a higher osseointegration ability compared to the CaP-Ag coating. Furthermore, the CaP-AgO coating demonstrated superior activity against S. aureus. These findings demonstrate the potential of the multifunctional coatings to address the challenges associated with inert ceramic implants by promoting bioactivity and combating bacterial infections.

Translation into Portuguese (Brazil), cultural adaptation and validation of Parathyroid Assessment of Symptoms (PAS) in patients with chronic kidney disease and hyperparathyroidism.

Chronic kidney disease (CKD) is related to high morbidity and mortality and loss of quality of life. Likewise, hyperparathyroidism is associated to progressive loss of renal function, with increased phosphate and decrease calcium levels, which induce the secretion of parathyroid hormone. To translate into Portuguese (Brazil), culturally adapt and validate the questionnaire Parathyroid Symptoms Assessment (PAS), following reliability and validity criteria in patients with chronic kidney disease and hyperparathyroidism. Methodological and cross-sectional study, carried out at São Lucas Hospital/PUCRS, Porto Alegre, Brazil. The PAS questionnaire validation process followed protocols from previous studies. After translating into Portuguese, it was applied to 100 patients with secondary (SHPT) and tertiary or persistent (THPT) hyperparathyroidism. For PAS validation data, patients responded to the Short Form Health 36 (SF-36) questionnaire. Reliability criteria were evaluated using intraclass correlation coefficient (ICC) and Cronbach's alpha (α-C). Validity was assessed by Spearman's correlation coefficient between PAS and SF-36 values. Participant's mean age was 55.6 ± 15.6 years, 61% was male, and 68% was diagnosed with SHPT. Among 100 patients, 53% performed a PAS retest (ICC = 0.83). The internal reliability by α-C was 0.86. Negative correlations were observed between PAS questions and SF-36 physical and mental domains, which ranged from 0.3 to 0.7. The Brazilian version of the PAS questionnaire was found to be valid and reliable. The PAS questionnaire can be used to evaluate quality of life in Brazilian patients with hyperparathyroidism who speak Portuguese.