Development of a novel method based on extraction mediated by a semipermeable membrane to determine Cd and Cr in sugar by graphite furnace atomic absorption spectrometry.

This work proposes a novel method to determine the Cd(II) and Cr(III) content in commercial sugar samples. It is based on the extraction of the analytes (as ammonium pyrrolidine dithiocarbamate complexes) into a semipermeable membrane device (SPMD) filled with CHCl3. After extraction, the SPMD was deployed and opened, and the analytes were recovered from the organic phase by back extraction with a 4.2 mol L-1 HNO3 solution. The analytes present in the acid extract were measured with graphite furnace atomic absorption spectrometry. Under optimized conditions, the limit of quantification of the method was 1.2 and 3.1 ng g-1 for Cd(II) and Cr(III), respectively. Twelve samples of different types of sugar were analyzed. In addition, a recovery test was performed to evaluate the accuracy of the method. The recovery percentage was 90 %-102 % for Cd(II) and 85.2 %-103 % for Cr(III).

Environmentally friendly screen-printed electrodes for the selective detection of 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in forensic analysis.

In response to the growing need for sustainable analytical methods, this study explores the repurposing of screen-printed electrodes (SPEs) that would otherwise be discarded. This involves recoating the working electrode surface with a graphite (Gr) and chitosan (CTS) dispersion, creating a reusable SPE (SPE-Gr/CTS). Demonstrating its utility, SPE-Gr/CTS was employed for the detection of 4-bromo-2,5-dimethoxyphenethylamine (2C-B), a phenylethylamine commonly used for recreational proposes. Identifying 2C-B in fluid oral and seized samples is of great interest for forensic and toxicological applications. The 2C-B detection using SPE-Gr/CTS was optimized in Britton-Robinson buffer solution (0.1 mol L-1) at pH 2.0, employing square-wave adsorptive stripping voltammetry. The electrochemical behavior of 2C-B on SPE-Gr/CTS exhibited one irreversible oxidation and a reversible redox process. The proposed method presented a dynamic linear range for 2C-B determination (0.05 to 7.5 µmol L-1) with a low LOD (0.015 µmol L-1). Moreover, the stability of 2C-B electrochemical responses on SPE-Gr/CTS was confirmed using the same or different electrodes (N = 3), with a relative standard deviation of less than 5.0%. Interference studies with seventeen other illicit drugs and adulterants demonstrated that the proposed method is selective for 2C-B detection even in the presence of these substances. Real seized and oral fluid samples containing 2C-B were analyzed using this method, and the results were confirmed by LC-MS. The proposed device demonstrates to be an environmentally friendly and selective sensor for 2C-B detection in forensic analysis, offering a rapid and straightforward screening method for seized and biological samples. In addition, a portable and sensitive determination of 2C-B in forensic samples is presented with minimal sample consumption (50 µL).

Cost-effective quantification of uric acid using niobium oxide and graphene oxide-modified pencil-drawn electrodes on PVC substrates.

This study introduces a cost-effective approach for quantifying uric acid (UA), the main antioxidant species in human physiology and implicated in inflammatory regulation. Using a PVC substrate and pencil drawing technique, electrodes were fabricated and modified with niobium oxide and graphene oxide via a straightforward "drop casting" method. The nanostructures of the substrate, electrode, and modified electrode were evaluated using SEM images. The synergistic effect between these materials significantly facilitated the uric acid oxidation process with a 400 mV peak potential shift and 45% current increase. The evaluation of the electrode's response to common blood and urine components showed minimal deviation. Among the components tested-ascorbic acid, glucose, nitrate, nitrite, cysteine, urea, creatinine, and ammonium ion-only the ammonium ion exhibited a 10% interference at concentrations commonly found in urine. The sensors showed a good detection limit of 8.7 µmol L-1, with a wide linear range from 8.7 to 2000 µmol L-1 with a correlation factor of 0.9993 for five different sensors. The reproducibility and repeatability of the produced sensors were estimated by the RSD at 4% and 1%, respectively. Synthetic urine samples spiked exhibited reliable analysis, with recovery values within a 5% error margin. This work presents a practical, simple, and affordable sensor platform for rapid and accurate UA quantification.

The therapeutic potential of reduced graphene oxide in attenuating cuprizone-induced demyelination in mice.

Reduced graphene oxide (rGO) has unique physicochemical properties that make it suitable for therapeutic applications in neurodegenerative scenarios. This study investigates the therapeutic potential of rGO in a cuprizone-induced demyelination model in mice through histomorphological techniques and analysis of biochemical parameters. We demonstrate that daily intraperitoneal administration of rGO (1 mg ml-1) for 21 days tends to reduce demyelination in theCorpus callosumby decreasing glial cell recruitment during the repair mechanism. Additionally, rGO interferes with oxidative stress markers in the brain and liver indicating potential neuroprotective effects in the central nervous system. No significant damage to vital organs was observed, suggesting that multiple doses could be used safely. However, further long-term investigations are needed to understand rGO distribution, metabolism, routes of action and associated challenges in central neurodegenerative therapies. Overall, these findings contribute to the comprehension of rGO effectsin vivo, paving the way for possible future clinical research.

Graphene Quantum Dots from Natural Carbon Sources for Drug and Gene Delivery in Cancer Treatment.

Cancer therapy is constantly evolving, with a growing emphasis on targeted and efficient treatment options. In this context, graphene quantum dots (GQDs) have emerged as promising agents for precise drug and gene delivery due to their unique attributes, such as high surface area, photoluminescence, up-conversion photoluminescence, and biocompatibility. GQDs can damage cancer cells and exhibit intrinsic photothermal conversion and singlet oxygen generation efficiency under specific light irradiation, enhancing their effectiveness. They serve as direct therapeutic agents and versatile drug delivery platforms capable of being easily functionalized with various targeting molecules and therapeutic agents. However, challenges such as achieving uniform size and morphology, precise bandgap engineering, and scalability, along with minimizing cytotoxicity and the environmental impact of their production, must be addressed. Additionally, there is a need for a more comprehensive understanding of cellular mechanisms and drug release processes, as well as improved purification methods. Integrating GQDs into existing drug delivery systems enhances the efficacy of traditional treatments, offering more efficient and less invasive options for cancer patients. This review highlights the transformative potential of GQDs in cancer therapy while acknowledging the challenges that researchers must overcome for broader application.

Non-Cytotoxic Graphene Nanoplatelets Upregulate Cell Proliferation and Self-Renewal Genes of Mesenchymal Stem Cells.

Graphene nanoplatelets (UGZ-1004) are emerging as a promising biomaterial in regenerative medicine. This study comprehensively evaluates UGZ-1004, focusing on its physical properties, cytotoxicity, intracellular interactions, and, notably, its effects on mesenchymal stem cells (MSCs). UGZ-1004 was characterized by lateral dimensions and layer counts consistent with ISO standards and demonstrated a high carbon purity of 0.08%. Cytotoxicity assessments revealed that UGZ-1004 is non-toxic to various cell lines, including 3T3 fibroblasts, VERO kidney epithelial cells, BV-2 microglia, and MSCs, in accordance with ISO 10993-5:2020/2023 guidelines. The study focused on MSCs and revealed that UGZ-1004 supports their gene expression alterations related to self-renewal and proliferation. MSCs exposed to UGZ-1004 maintained their characteristic surface markers. Importantly, UGZ-1004 promoted significant upregulation of genes crucial for cell cycle regulation and DNA repair, such as CDK1, CDK2, and MDM2. This gene expression profile suggests that UGZ-1004 can enhance MSC self-renewal capabilities, ensuring robust cellular function and longevity. Moreover, UGZ-1004 exposure led to the downregulation of genes associated with tumor development, including CCND1 and TFDP1, mitigating potential tumorigenic risks. These findings underscore the potential of UGZ-1004 to not only bolster MSC proliferation but also enhance their self-renewal processes, which are critical for effective regenerative therapies. The study highlights the need for continued research into the long-term impacts of graphene nanoplatelets and their application in MSC-based regenerative medicine.

Graphitic carbon nitride as a novel anticancer agent: potential mechanisms and efficacy in prostate cancer and glioblastoma treatment.

Carbon-derived compounds are gaining traction in the scientific community because of their unique properties, such as conductivity and strength, and promising innovations in technology and medicine. Graphitic nitride carbon (g-C3N4) stands out among these compounds because of its potential in antitumor therapies. This study aimed to assess g-C3N4's antitumor potential and cytotoxic mechanisms. Prostate cancer (DU-145) and glioblastoma (U87) cell lines were used to evaluate antitumor effects, whereas RAW 264.7 and HFF-1 non-tumor cells were used for selectivity evaluation. The synthesized g-C3N4 particles underwent comprehensive characterization, including the assessment of particle size, morphology, and oxygen content, employing various techniques, such as X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and atomic force microscopy. The results indicated that g-C3N4 significantly affected tumor cell proliferation and viability, exhibiting high cytotoxicity within 48 h. In non-tumor cells, minimal effects on proliferation were observed, except for damage to the cell membranes of RAW 264.7 cells. Moreover, g-C3N4 changed the cell morphology and ultrastructure, affecting cell migration in U87 cells and potentially enhancing migration in RAW 264.7 cells. Biochemical assays in Balb/C mice revealed alterations in alanine aminotransferase, aspartate aminotransferase, and amylase levels. In conclusion, g-C3N4 demonstrated promising antitumor effects with minimal toxicity to non-tumor cells, suggesting its potential in neoplasm treatment.

Electrochemistry of chloramphenicol on laser-induced graphene electrodes and its voltammetric determination in honey.

Laser scribing is a promising technology for the rapid and large-scale production of low-cost electrochemical sensors from diverse substrates. Polyimide has been the most popular so far because of its low cost, flexibility and capability of generating high-quality porous graphene films, known as laser-induced graphene (LIG). Herein we report the electrochemistry of chloramphenicol (CAP) on LIG electrodes and its determination in honey samples. LIG electrodes were fabricated by the photothermal conversion of sp3 carbon within the polymeric matrix into sp2 carbon using a CO2 laser cutter. The LIG electrode associated with differential pulse voltammetry (DPV) showed good linearity (R2 > 0.99) in the range from 10 to 160 µmol L-1 with a limit of detection of 1.0 µmol L-1 and good precision (RSD < 5%) for the electrochemical reduction of CAP species. Detection was possible free from the interference of other antibiotics, such as amoxicillin, tetracycline, sulfanilamide, and sulfamethoxazole. Spiked honey samples were analyzed by the standard-addition method and recovery values between 86 and 109% were obtained, which confirmed the absence of sample matrix effects. Therefore, the proposed sensor is an alternative, feasible, low-cost, and powerful analytical tool for the determination of CAP in honey.

Production of pyrite-based catalysts supported on graphene oxide and zinc oxide to treat drug mixture via advanced oxidation processes.

Advanced oxidation processes (AOP) stood out as an efficient alternative for the treatment of organic contaminants. In this work, there were proposed syntheses of mixed catalysts of pyrite and graphene oxide and pyrite and zinc oxide to treat a mixture of the drugs atenolol and propranolol in aqueous solution through the photo-Fenton process with ultraviolet radiation. The efficiency of the methodologies used in the syntheses was confirmed through different characterization analyses. It was verified that the pyrite and zinc oxide catalyst led to the best contaminant degradation percentages with values equal to 88 and 84% for the groups monitored at the wavelengths (λ) of 217 and 281 nm. The degradation kinetics presented a good fit to the kinetic model proposed by Chan and Chu (2003) with R2 equal to 0.99, indicating a pseudo-first-order degradation profile. Finally, toxicity tests were carried out with two types of seeds, watercress and cabbage, for the solution before and after treatment. The cabbage seeds showed a reduction in germination percentages for the samples after treatments, while no toxicity was observed for watercress ones. This highlights the importance of evaluating the implications caused by products in relation to different organisms representing the biota.

Digitalization of Enzyme-Linked Immunosorbent Assay with Graphene Field-Effect Transistors (G-ELISA) for Portable Ferritin Determination.

Herein, we present a novel approach to quantify ferritin based on the integration of an Enzyme-Linked Immunosorbent Assay (ELISA) protocol on a Graphene Field-Effect Transistor (gFET) for bioelectronic immunosensing. The G-ELISA strategy takes advantage of the gFET inherent capability of detecting pH changes for the amplification of ferritin detection using urease as a reporter enzyme, which catalyzes the hydrolysis of urea generating a local pH increment. A portable field-effect transistor reader and electrolyte-gated gFET arrangement are employed, enabling their operation in aqueous conditions at low potentials, which is crucial for effective biological sample detection. The graphene surface is functionalized with monoclonal anti-ferritin antibodies, along with an antifouling agent, to enhance the assay specificity and sensitivity. Markedly, G-ELISA exhibits outstanding sensing performance, reaching a lower limit of detection (LOD) and higher sensitivity in ferritin quantification than unamplified gFETs. Additionally, they offer rapid detection, capable of measuring ferritin concentrations in approximately 50 min. Because of the capacity of transistor miniaturization, our innovative G-ELISA approach holds promise for the portable bioelectronic detection of multiple biomarkers using a small amount of the sample, which would be a great advancement in point-of-care testing.

Bacteria-Derived Cellulose Membranes Modified with Graphene Oxide-Silver Nanoparticles for Accelerating Wound Healing.

This study reports on the modification of bacterial cellulose (BC) membranes produced by static fermentation of Komagataeibacter xylinus bacterial strains with graphene oxide-silver nanoparticles (GO-Ag) to yield skin wound dressings with improved antibacterial properties. The GO-Ag sheets were synthesized through chemical reduction with sodium citrate and were utilized to functionalize the BC membranes (BC/GO-Ag). The BC/GO-Ag composites were characterized to determine their surface charge, morphology, exudate absorption, antimicrobial activity, and cytotoxicity by using fibroblast cells. The antimicrobial activity of the wound dressings was assessed against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The results indicate that the BC/GO-Ag dressings can inhibit ∼70% of E. coli cells. Our findings also revealed that the porous BC/GO-Ag antimicrobial dressings can efficiently retain 94% of exudate absorption after exposure to simulated body fluid (SBF) for 24 h. These results suggest that the dressings could absorb excess exudate from the wound during clinical application, maintaining adequate moisture, and promoting the proliferation of epithelial cells. The BC/GO-Ag hybrid materials exhibited excellent mechanical flexibility and low cytotoxicity to fibroblast cells, making excellent wound dressings able to control bacterial infectious processes and promote the fast healing of dermal lesions.

A cost-effective method for the sensitive detection of levofloxacin using a 3D composite electrode composed of nail polish, graphite and aluminium oxide.

The potential impact on human health and the environment has spurred significant interest in detecting and quantifying pharmaceutical compounds across various matrices, from environmental to biological samples. Here, we present an electrochemical approach for determining levofloxacin in drug, synthetic urine, water, and breast milk samples. An affordable sensor was constructed using 3D printing and composite material based on nail polish, graphite, and aluminum oxide. The conductive composite material was characterized spectroscopically, electrochemically, and by imaging techniques. Subsequently, an electrochemical method based on square wave voltammetry was optimized and applied. The method exhibited good sensitivity (5.11 ± 0.0912 µA L µmol-1 cm-2) and enhanced stability (RSD = 7.2%), with electrochemical responses correlating with the concentration of levofloxacin in the samples tested, yielding recovery values in the range of 98 to 111%. The developed method demonstrated a robust linear working range from 2 to 100 µmol L-1 and a nanomolar detection limit of 128 nmol L-1, rendering it suitable for quantitative analysis. The sensor also shows promise as a platform for the sensitive detection of pharmaceutical compounds, contributing to greater safety and sustainability in these domains.

Microfluid biosensor for detection of hpv in patient scraping samples: Determining E6 and E7 oncogenes.

E6 and E7 oncogenes are pivotal in the carcinogenic transformation in HPV infections and efficient diagnostic methods can ensure the detection and differentiation of HPV genotype. This study describes the development and validation of an electrochemical, label-free genosensor coupled with a microfluidic system for detecting the E6 and E7 oncogenes in cervical scraping samples. The nanostructuring employed was based on a cysteine and graphene quantum dots layer that provides functional groups, surface area, and interesting electrochemical properties. Biorecognition tests with cervical scraping samples showed differentiation in the voltammetric response. Low-risk HPV exhibited a lower biorecognition response, reflected in ΔI% values of 82.33 % ± 0.29 for HPV06 and 80.65 % ± 0.68 for HPV11 at a dilution of 1:100. Meanwhile, high-risk, HPV16 and HPV18, demonstrated ΔI% values of 96.65 % ± 1.27 and 93 % ± 0.026, respectively, at the same dilution. Therefore, the biorecognition intensity followed the order: HPV16 >HPV18 >HPV06 >HPV11. The limit of detection and the limit of quantification of E6E7 microfluidic LOC-Genosensor was 26 fM, and 79.6 fM. Consequently, the E6E7 biosensor is a valuable alternative for clinical HPV diagnosis, capable of detecting the potential for oncogenic progression even in the early stages of infection.

Analysis of human biological samples using porous graphitic carbon columns and liquid chromatography-mass spectrometry: a review.

Liquid chromatography-mass spectrometry (LC-MS) has emerged as a powerful analytical technique for analyzing complex biological samples. Among various chromatographic stationary phases, porous graphitic carbon (PGC) columns have attracted significant attention due to their unique properties-such as the ability to separate both polar and non-polar compounds and their stability through all pH ranges and to high temperatures-besides the compatibility with LC-MS. This review discusses the applicability of PGC for SPE and separation in LC-MS-based analyses of human biological samples, highlighting the diverse applications of PGC-LC-MS in analyzing endogenous metabolites, pharmaceuticals, and biomarkers, such as glycans, proteins, oligosaccharides, sugar phosphates, and nucleotides. Additionally, the fundamental principles underlying PGC column chemistry and its advantages, challenges, and advances in method development are explored. This comprehensive review aims to provide researchers and practitioners with a valuable resource for understanding the capabilities and limitations of PGC columns in LC-MS-based analysis of human biological samples, thereby facilitating advancements in analytical methodologies and biomedical research.

Graphene-enhanced PCL electrospun nanofiber scaffolds for cardiac tissue engineering.

Cardiovascular diseases, particularly myocardial infarction, have significant healthcare challenges due to the limited regenerative capacity of injured heart tissue. Cardiac tissue engineering (CTE) offers a promising approach to repairing myocardial damage using biomaterials that mimic the heart's extracellular matrix. This study investigates the potential of graphene nanopowder (Gnp)-enhanced polycaprolactone (PCL) scaffolds fabricated via electrospinning to improve the properties necessary for effective cardiac repair. This work aimed to analyze scaffolds with varying graphene concentrations (0.5%, 1%, 1.5%, and 2% by weight) to determine their morphological, chemical, mechanical, and biocompatibility characteristics. The results presented that incorporating graphene improves PCL scaffolds' mechanical properties and cellular interactions. The optimal concentration of 1% graphene significantly enhanced mechanical properties and biocompatibility, promoting cell adhesion and proliferation. These findings suggest that Gnp-enhanced PCL scaffolds at this concentration can serve as a potent substrate for CTE providing insights into designing more effective biomaterials for myocardial restoration.

The Tunable Parameters of Graphene-Based Biosensors.

Graphene-based surface plasmon resonance (SPR) biosensors have emerged as a promising technology for the highly sensitive and accurate detection of biomolecules. This study presents a comprehensive theoretical analysis of graphene-based SPR biosensors, focusing on configurations with single and bimetallic metallic layers. In this study, we investigated the impact of various metallic substrates, including gold and silver, and the number of graphene layers on key performance metrics: sensitivity of detection, detection accuracy, and quality factor. Our findings reveal that configurations with graphene first supported on gold exhibit superior performance, with sensitivity of detection enhancements up to 30% for ten graphene layers. In contrast, silver-supported configurations, while demonstrating high sensitivity, face challenges in maintaining detection accuracy. Additionally, reducing the thickness of metallic layers by 30% optimizes light coupling and enhances sensor performance. These insights highlight the significant potential of graphene-based SPR biosensors in achieving high sensitivity of detection and reliability, paving the way for their application in diverse biosensing technologies. Our findings pretend to motivate future research focusing on optimizing metallic layer thickness, improving the stability of silver-supported configurations, and experimentally validating the theoretical findings to further advance the development of high-performance SPR biosensors.

A promising poly (e-caprolactone)/graphene-based scaffold as an antibacterial in regenerating bone tissue.

Scaffolds are 3D biomaterials that provide an environment for cell regeneration. In the context of bone remodeling, poly(e-caprolactone) (PCL) combined with graphene has been developed as the scaffold. It is imperative for scaffolds to possess antibacterial properties in order to properly reduce the risk of potential infections.Therefore, this study aims to analyze the antibacterial characteristics of PCL/graphene scaffolds against Staphylococcus aureus (S. aureus) and Porphyromonas gingivalis (P. gingivalis) in vitro. In this study, five different groups were used, including PCL (K-), Amoxicillin (K+), PCL/Graphene 0.5 wt%, PCL/graphene 1 wt% and PCL/Graphene 1.5 wt%. All experiments were performed in triplicates and were repeated three times, and the diffusion method by Kirby-Bauer test was used. The disc was incubated with S. aureus and P. gingivalis for 24 hours and then the diameter of the inhibition zone was measured. The results showed that the PCL/graphene scaffolds exhibited dose-dependent antibacterial activity against S. aureus and P. gingivalis. The inhibition zone diameter (IZD) against S. aureus of PCL/graphene 1 wt% was 9.53 ± 0.74 mm, and increased to 11.93 ± 0.92 mm at a concentration of 1.5 wt% of graphene. The PCL/graphene scaffold with 1.5 wt% exhibited a greater inhibitory effect, with an IZD of 12.56 ± 0.06 mm against P. gingivalis, while the inhibitory activity of the 1 wt% variant was relatively lower at 10.46 ± 0.24 mm. The negative control, PCL, and PCL/graphene 0.5 wt% exhibited no antibacterial activity sequentially (p = 1). Scaffolds of poly(e-caprolactone)/graphene exhibited an antibacterial activity at 1, and 1.5 wt% on S. aureus and P. gingivalis. The antibacterial properties of this scaffold make it a promising candidate for regenerating bone tissue.

Synthesis of superparamagnetic Fe3O4-graphene oxide-based material for the photodegradation of clonazepam.

The global concern over water pollution caused by contaminants of emerging concern has been the subject of several studies due to the complexity of treatment. Here, the synthesis of a graphene oxide-based magnetic material (GO@Fe3O4) produced according to a modified Hummers' method followed by a hydrothermal reaction was proposed; then, its application as a photocatalyst in clonazepam photo-Fenton degradation was investigated. Several characterization analyses were performed to analyze the structure, functionalization and magnetic properties of the composite. A 23 factorial design was used for the optimization procedure to investigate the effect of [H2O2], GO@Fe3O4 dose and pH on clonazepam degradation. Adsorption experiments demonstrated that GO@Fe3O4 could not adsorb clonazepam. Photo-Fenton kinetics showed that total degradation of clonazepam was achieved within 5 min, and the experimental data were better fitted to the PFO model. A comparative study of clonazepam degradation by different processes highlighted that the heterogeneous photo-Fenton process was more efficient than homogeneous processes. The radical scavenging test showed that O 2 · - was the main active free radical in the degradation reaction, followed by hydroxyl radicals (•OH) and holes (h+) in the valence layer; accordingly, a mechanism of degradation was proposed to describe the process.

Electrochemical detection of poly(3-hydroxybutyrate) production from Burkholderia glumae MA13 using a molecularly imprinted polymer-reduced graphene oxide modified electrode.

The development and application of an electrochemical sensor is reported for detection of poly(3-hydroxybutyrate) (P3HB) - a bioplastic derived from agro-industrial residues. To overcome the challenges of molecular imprinting of macromolecules such as P3HB, this study employed methanolysis reaction to break down the P3HB biopolymer chains into methyl 3-hydroxybutyrate (M3HB) monomers. Thereafter, M3HB were employed as the target molecules in the construction of molecularly imprinted sensors. The electrochemical device was then prepared by electropolymerizing a molecularly imprinted poly (indole-3-acetic acid) thin film on a glassy carbon electrode surface modified with reduced graphene oxide (GCE/rGO-MIP) in the presence of M3HB. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy with field emission gun (SEM-FEG), Raman spectroscopy, attenuated total reflection Fourier-transform infrared (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS) were employed to characterize the electrode surface. Under ideal conditions, the MIP sensor exhibited a wide linear working range of 0.1 - 10 nM and a detection limit of 0.3 pM (n = 3). The sensor showed good repeatability, selectivity, and stability over time. For the sensor application, the bioproduction of P3HB was carried out in a bioreactor containing the Burkholderia glumae MA13 strain and sugarcane byproducts as a supplementary carbon source. The analyses were validated through recovery assays, yielding recovery values between 102 and 104%. These results indicate that this MIP sensor can present advantages in the monitoring of P3HB during the bioconversion process.

Graphene Oxide Nanosheets for Bone Tissue Regeneration.

Bone tissue engineering is a promising alternative to repair wounds caused by cellular or physical accidents that humans face daily. In this sense, the search for new graphene oxide (GO) nanofillers related to their degree of oxidation is born as an alternative bioactive component in forming new scaffolds. In the present study, three different GOs were synthesized with varying degrees of oxidation and studied chemically and tissue-wise. The oxidation degree was determined through infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron (XPS), and Raman spectroscopy (RS). The morphology of the samples was analyzed using scanning electron microscopy (SEM). The oxygen content was deeply described using the deconvolution of RS and XPS techniques. The latter represents the oxidation degree for each of the samples and the formation of new bonds promoted by the graphitization of the material. In the RS, two characteristic bands were observed according to the degree of oxidation and the degree of graphitization of the material represented in bands D and G with different relative intensities, suggesting that the samples have different crystallite sizes. This size was described using the Tuinstra-Koenig model, ranging between 18.7 and 25.1 nm. Finally, the bone neoformation observed in the cranial defects of critical size indicates that the F1 and F2 samples, besides being compatible and resorbable, acted as a bridge for bone healing through regeneration. This promoted healing by restoring bone and tissue structure without triggering a strong immune response.