A new SERS quantitative analysis strategy for ultratrace chloramphenicol with Fe3O4@MIP nanocatalytic probe.

Three functional magnetic nanocatalytic probe, which integrates recognition, catalytic amplification, and separation enrichment, is a new approach to construct a simple, fast, highly selective, and sensitive analytical method. In this article, a new magnetic nanosurface molecularly imprinted polymer nanoprobe (Fe3O4@MIP) with trifunctionality was rapidly prepared using a microwave-assisted method with magnetic Fe3O4 nanoparticles as a substrate, chloramphenicol (CAP) as a template molecule, and methacrylic acid as a functional monomer. The characterized nanoprobe was found that could specifically recognize CAP, strongly catalyze the new indicator nanoreaction of fructose (DF)-HAuCl4. The gold nanoparticles (AuNPs) exhibit strong resonance Rayleigh scattering (RRS) and surface enhanced Raman scattering (SERS) effects. Upon addition of CAP, the SERS/RRS signals were linearly weakened. Accordingly, a new SERS/RRS analysis platform for highly sensitive and selective determination of CAP was constructed. The SERS linear range was 0.0125-0.1 nmol/L, with detection limit (DL) of 0.004 nmol/L CAP. Furthermore, it could be combined with magnet-enriched separation to further improve the sensitivity, with a DL of 0.04 pmol/L CAP. The SERS method has been used for the determination of CAP in real samples, with relative standard deviations of 2.37-9.89 % and the recovery of 95.24-107.1 %.

An aptasensor for chloramphenicol determination based on dual signal output of photoelectrochemistry and colorimetry.

In the present work, we developed an aptasensor to determine chloramphenicol (CAP) based on the dual signal output of photoelectrochemistry (PEC) and colorimetry. The Fe3+-doped porous tungsten trioxide was prepared by sol-gel method and coated on the ITO conductive glass to form ITO/p-W(Fe)O3. After assembling the captured DNA (cDNA) and the aptamer of CAP (apt) successively, the constructed ITO/p-W(Fe)O3-cDNA/apt aptasensor exhibited excellent photocurrent response under visible light irradiation in the presence of glucose, which provided the feasibility for PEC measurement with high sensitivity. In the presence of CAP, the apt left the ITO/p-W(Fe)O3 surface and AuNPs linked on the probe DNA would be assembled on it, which led to the decrease of photocurrent. Thanks to the oxidase-mimic catalytic performance of AuNPs and the recycling catalytic hydrolysis by exonuclease I, the measurement signal of the aptasensor could be amplified significantly, and the photocurrent decrease of the aptasensor was linearly related to the concentration of CAP in the range of 1.0 pM-10.0 nM and low detection limit was 0.36 pM. Meanwhile, the H2O2 produced from catalytic oxidation of glucose could oxidize TMB to blue oxTMB under HRP catalysis, which absorbance at 652 nm was linearly related to the concentration of CAP in the range of 5.0 pM-10.0 nM and low detection limit was 1.72 pM. Therefore, an aptasensor that determine CAP in real samples was successfully constructed with good precision of the relative standard deviation less than 5.7 % for PEC method and 7.3 % for colorimetric method, which can meet the analysis needs in different scenarios.

Dual emitting aggregation-induced electrochemiluminescence from tetrastyrene derivative for chloramphenicol detection.

Chloramphenicol (CAP) poses a threat to human health due to its toxicity and bioaccumulation, and it is very important to measure it accurately and sensitively. This work explored a host-guest recognition strategy to mediate dual aggregation-induced electrochemiluminescence (AIECL) of 1,1,2,2-tetrakis(4-(pyridin-4-yl) phenyl)-ethene (TPPE) for ratio detection of CAP, in which, cucurbit[8]uril (CB[8]) served as host to assemble guest TPPE. The resulting supramolecular complex CB[8]-TPPE exhibited excellent dual-AIECL-emission with signal strength approximately four times that of TPPE aggregates and black hole quencher-1 (BHQ1) could efficiently quench dual-AIECL signal. CB[8]-TPPE coupled dual-function quencher BHQ1 and high-efficiency DNA reactor to achieve ultra-sensitive detection of CAP, exhibiting a linearity range of 10 fmol·L-1-100 nmol·L-1 and limit of detection of 1.81 fmol·L-1. CB[8]-TPPE provides a novel way to improve the dual-emission of TPE derivatives and sets up a promising platform for CAP detection, demonstrating a good practical application potential.

A facile electrochemical aptasensor for chloramphenicol detection based on synergistically photosensitization enhanced by SYBR Green I and MoS2.

This study reports the development of a photocatalytic electrochemical aptasensor for the purpose of detecting chloramphenicol (CAP) antibiotic residues in water by utilizing SYBR Green I (SG) and chemically exfoliated MoS2 (ce-MoS2) as synergistically signal-amplification platforms. The Au nanoparticles (AuNPs) were electrodeposited onto the surface of an indium tin oxide (ITO) electrode. After that, the thiolate-modified cDNA, also known as capture DNA, was combined with the aptamer. Subsequently, photosensitized SG molecules and ce-MoS2 nanomaterial were inserted into the groove of the resultant double-stranded DNA (dsDNA). The activation of the photocatalytic process upon exposure to light resulted in the generation of singlet oxygen. The singlet oxygen effectively split the dsDNA, resulting in significant enhancement in the current of [Fe(CN)6]3-/4-. When the CAP was present, both SG molecules and ce-MoS2 broke away from the dsDNA, which turned off the photosensitization response, leading to significant reduction in the current of [Fe(CN)6]3-/4-. Under the optimal conditions, the aptasensor exhibited a linear relationship between the current of [Fe(CN)6]3-/4- with logarithmic concentrations of CAP from 20 to 1000 nM, with a detection of limit (3σ) of 3.391 nM. The aptasensor also demonstrated good selectivity towards CAP in the presence of interfering antibiotics, such as tetracycline, streptomycin, levofloxacin, ciprofloxacin, and sulfadimethoxine. Additionally, the results obtained from the analysis of natural water samples using the proposed aptasensor were consistent with the findings acquired through the use of a liquid chromatograph-mass spectrometer. Therefore, with its simplicity and high selectivity, this aptasensor can potentially detect alternative antibiotics in environmental water samples by replacing the aptamers based on photosensitization.

Development and validation of rapid screening of 192 veterinary drug residues in aquatic products using HPLC-HRMS coupled with QuEChERS.

The presence of veterinary drug residues in aquatic products represents a significant challenge to food safety. The current detection methods, limited in both scope and sensitivity, underscore the urgent need for more advanced techniques. This research introduces a swift and potent screening technique using high-performance liquid chromatography-high-resolution mass spectrometry (HPLC-HRMS) and a refined QuEChERS protocol, allowing simultaneous qualitative and semi-quantitative analysis of 192 residues. A comprehensive database, employing full scan mode and data-dependent secondary mass spectroscopy, enhances screening accuracy. The method involves efficient extraction using 90% acetonitrile, dehydration with Na2SO4, and acetic acid, followed by cleanup using dispersive solid-phase extract sorbent primary secondary amine. It is suitable for samples with varying fat content, offering detection limits ranging from 0.5 to 10 µg/kg, high recovery rates (60-120%), and low relative standard deviations (<20%). Practical application has validated its effectiveness for multi-residue screening, marking a significant advancement in food safety evaluation.

Membranome-based identification of amino acid substitution in Haemophilus influenzae multidrug efflux pump HmrM for reduced chloramphenicol susceptibility.

A decreased chloramphenicol susceptibility in Haemophilus influenzae is commonly caused by the activity of chloramphenicol acetyltransferases (CATs). However, the involvement of membrane proteins in chloramphenicol susceptibility in H. influenzae remains unclear. In this study, chloramphenicol susceptibility testing, whole-genome sequencing, and analyses of membrane-related genes were performed in 51 H. influenzae isolates. Functional complementation assays and structure-based protein analyses were conducted to assess the effect of proteins with sequence substitutions on the minimum inhibitory concentration (MIC) of chloramphenicol in CAT-negative H. influenzae isolates. Six isolates were resistant to chloramphenicol and positive for type A-2 CATs. Of these isolates, A3256 had a similar level of CAT activity but a higher chloramphenicol MIC relative to the other resistant isolates; it also had 163 specific variations in 58 membrane genes. Regarding the CAT-negative isolates, logistic regression and receiver operator characteristic curve analyses revealed that 48T > G (Asn16Lys), 85 C > T (Leu29Phe), and 88 C > A (Leu30Ile) in HI_0898 (emrA), and 86T > G (Phe29Cys) and 141T > A (Ser47Arg) in HI_1177 (artM) were associated with enhanced chloramphenicol susceptibility, whereas 997G > A (Val333Ile) in HI_1612 (hmrM) was associated with reduced chloramphenicol susceptibility. Furthermore, the chloramphenicol MIC was lower in the CAT-negative isolates with EmrA-Leu29Phe/Leu30Ile or ArtM-Ser47Arg substitution and higher in those with HmrM-Val333Ile substitution, relative to their counterparts. The Val333Ile substitution was associated with enhanced HmrM protein stability and flexibility and increased chloramphenicol MICs in CAT-negative H. influenzae isolates. In conclusion, the substitution in H. influenzae multidrug efflux pump HmrM associated with reduced chloramphenicol susceptibility was characterised.

Highly enhanced chloramphenicol adsorption performance of MIL-53-NH2(Al)-derived porous carbons modified with tannic acid.

The worldwide demand for antibiotics has experienced a notable surge, propelled by the repercussions of the COVID-19 pandemic and advancements in the global healthcare sector. A prominent challenge confronting humanity is the unregulated release of antibiotic-laden wastewater into the environment, posing significant threats to public health. The adoption of affordable carbon-based adsorbents emerges as a promising strategy for mitigating the contamination of antibiotic wastewater. Here, we report the synthesis of novel porous carbons (MPC) through a direct pyrolysis of MIL-53-NH2(Al) and tannic acid (TANA) under N2 atmosphere at 800 °C for 4 h. The effect of TANA amount ratios (0%-20%, wt wt-1) on porous carbon structure and adsorption performance was investigated. Results showed that TANA modification resulted in decreased surface area (1,600 m2 g-1-949 m2 g-1) and pore volume (2.3 cm3 g-1-1.7 cm3 g-1), but supplied hydroxyl functional groups. Adsorption kinetic, intraparticle diffusion, and isotherm were examined, indicating the best fit of Elovich and Langmuir models. 10%-TANA-MPC obtained an ultrahigh adsorption capacity of 564.4 mg g-1, which was approximately 2.1 times higher than that of unmodified porous carbon. 10%-TANA-MPC could be easily recycled up to 5 times, and after reuse, this adsorbent still remained highly stable in morphology and surface area. The contribution of H bonding, pore-filling, electrostatic and π-π interactions to chloramphenicol adsorption was clarified. It is recommended that TANA-modified MIL-53-NH2(Al)-derived porous carbons act as a potential adsorbent for removal of pollutants effectively.

Beetle-inspired AuNPs semi-embedded colloidal crystal chips for the highly sensitive and colored detection of chloramphenicol in foods.

Inspired by the desert beetle, a novel biomimetic chip was developed to detect chloramphenicol (CP). The chip was characterized by a periodic array in which hydrophobic Au nanoparticles (AuNPs) were semi-embedded on hydrophilic polymethyl methacrylate (PMMA) spheres. Among them, the AuNPs exhibited both a localized surface plasmon resonance effect to amplify the reflected signal and a synergistic effect with PMMA spheres to create a significant hydrophilic-hydrophobic interface, which facilitated the enrichment of target CP molecules and improved sensitivity. After optimization, the chip showed direct, ultrasensitive (as low as 0.2 ng/mL), fast (5 min), and selective detection of CP with a wide concentration range extending from 0.2 ng/mL to 1000 ng/mL. During detection, color changes of the chip were observed by naked eyes without any color display equipment. The recovery of CP was between 94.65 % and 108.70 % in chicken and milk samples.

Regulating the electronic structure by P-doping cobalt-based catalyst for atomic hydrogen mediated electrocatalytic dechlorination.

Electrocatalytic dechlorination by atomic hydrogen (H*) is efficient, but limited by the low efficiency of H* production. Herein, a phosphorus-doped cobalt nitrogen carbon catalyst (Co-NP/C) was prepared, which had high catalytic activity in a wide pH range (3-11). The turnover frequency of Co-NP/C (3.54 min-1) was 1.21-59000 times superior to that of current Pd-based and non-noble metal catalysts (0.00006-2.92 min-1). Co-NP/C significantly enhanced H* generation, which was 1.52, 2.44, and 3.77 times stronger than that of Co-N/C, NP/C, and N/C, respectively, since the introduction of phosphorus was found enhanced the electron density of cobalt and regulated the electron transfer. Co-NP/C showed outstanding catalytic performance after ten cycles and could achieve nearly complete chloramphenicol removal. This regulation method was verified to be effective for other non-noble metal (Fe, Mn, Cu, Ni) phosphorus doped catalysts, proposing a general class for efficient electrochemical dechlorination, which would be of great significance for the elimination of chlorinated organic pollutants.

Chloramphenicol alleviates 5-fluorouracil-induced cellular senescence through activation of autophagy.

5-Fluorouracil (5-FU) is a first-line treatment for colorectal cancer, but side effects such as severe diarrhea are common in clinical use and have been linked to its induction of normal cell senescence. Chloramphenicol (CAP) is an antibiotic commonly used to treat typhoid or anaerobic infections, but its senescence-related aspects have not been thoroughly investigated. Here, we used 5-FU to induce senescence in human umbilical vein endothelial cells (HUVECs) and investigated the relationship between CAP and cellular senescence at the cellular level. In a model of cellular senescence induced by 5-FU treatment, we discovered that CAP treatment reversed the rise in the percentage of senescence-associated galactosidase (SA-ß-gal)-positive cells and decreased the expression of senescence-associated proteins (p16), senescence-associated genes (p21), and senescence-associated secretory phenotypes (SASPs: IL-6, TNF-α). In addition, CAP subsequently restored the autophagic process inhibited by 5-FU and upregulated the levels of autophagy-related proteins. Mechanistically, we found that CAP restored autophagic flux by inhibiting the mTOR pathway, which in turn alleviated FU-induced cellular senescence. Our findings suggest that CAP may help prevent cellular senescence and restore autophagy, opening up new possibilities and approaches for the clinical management of colorectal cancer.

Synergistic effect on simultaneous treatment of Cr(VI) and chloramphenicol using a non-thermal plasma technology.

Toxic organic and heavy metal contaminants commonly exist in industrial waste stream(s) and treatment is of great challenge. In this study, a dielectric barrier discharge (DBD) non-thermal plasma technology was employed for the simultaneous treatment of two important contaminants, chloramphenicol (CAP) and Cr(VI) in an aqueous solution through redox transformations. More than 70% of CAP and 20% of TOC were degraded in 60 min, while Cr(VI) was completely removed in 10 min. The hydroxyl radicals were the main active species for the degradation. Meanwhile, the consumption of hydroxyl radicals was beneficial to the reduction of Cr(VI). The synergistic effect was investigated between CAP degradation and Cr(VI) reduction. The reduction of Cr(VI) would be enhanced in the presence of CAP with a low concentration and could be inhibited under a high concentration, because part of hydroxyl radicals could be consumed by the low-concentration CAP and the obtained intermediates with a higher kinetic rate. However, CAP with a high concentration could react with such reductive species as eaq- and •H, which could compete with Cr(VI) and inhibit the reduction. In addition, the presence of Cr(VI) enhanced the degradation and mineralization of CAP; the study of obtained intermediates indicated that the presence of Cr(VI) changed the degradation path of CAP as Cr(VI) would react with reductive species, enhance the generation of hydroxyl radicals, and cause more hydroxylation reactions. Moreover, the mechanism for the simultaneous redox transformations of CAP and Cr(VI) was illustrated. This study indicates that the DBD non-thermal plasma technology can be one of better solutions for simultaneous elimination of heavy metal and organic contaminants in aquatic environments.

Well-ordered Au@Ag NBPs/SiO2 nanoarray for sensitive detection of chloramphenicol via DNAzyme-assisted SERS sensing.

Misuse of chloramphenicol (CAP) can lead to severe food safety issues. Therefore, the accurate and sensitive detection of CAP residues is important for public health. Herein, a convenient and reliable interfacial self-assembly technique was used to form a uniform Au@Ag nanobipyramids (NBPs) film on an ordered SiO2 nanosphere array (SiO2 NS), which served as a Raman-enhanced substrate. In conjunction with a deoxyribonucleic acid enzyme-induced signal amplification strategy, we developed a novel surface-enhanced Raman scattering (SERS) biosensor for the selective and sensitive detection of CAP. The biosensor exhibited a detection limit of 6.42 × 10-13 mol·L-1 and a detection range of 1.0 × 10-12-1.0 × 10-6 mol·L-1. The biosensor could detect CAP in spiked milk samples with a high accuracy, and its recovery rates ranged from 97.88% to 107.86%. The as-developed biosensor with the advantages of high sensitivity and high selectivity offers a new strategy for the rapid, reliable and sensitive detection of CAP, rendering it applicable to food safety control.

Ultrasensitive Ti3C2Tx@Pt-Based Immunochromatography with Catalytic Amplification and a Dual Signal for the Detection of Chloramphenicol in Animal-Derived Foods.

Herein, a catalytic amplification enhanced dual-signal immunochromatographic assay (ICA) based on Pt nanoparticles (Pt NPs) modified with Ti3C2Tx MXene (Ti3C2Tx@Pt) was first developed for chloramphenicol (CAP) in animal-derived foods. Due to the large specific surface area and abundant active sites of Ti3C2Tx@Pt, they can be loaded with hundreds of Pt NPs to enhance their catalytic activity, resulting in a significant increase in the detection sensitivity; the sensitivity was up to 50-fold more sensitive than the reported ICA for CAP. The LODs of the developed method for milk/chicken/fish were 0.01 µg/kg, the LOQs were 0.03 µg/kg and the recovery rates were 80.5-117.0%, 87.2-118.1% and 92.7-117.9%, with corresponding variations ranging from 3.1 to 9.6%, 6.0 to 12.7% and 6.0 to 13.6%, respectively. The linear range was 0.0125-1.0 µg/kg. The results of the LC-MS/MS confirmation test on 30 real samples had a good correlation with that of our established method (R2 > 0.98), indicating the practical reliability of the established method. The above results indicated that an ICA based on the Ti3C2Tx@Pt nanozyme has excellent potential as a food safety detection tool.

Detection of florfenicol resistance in opportunistic Acinetobacter spp. infections in rural Thailand.

Florfenicol (Ff) is an antimicrobial agent belonging to the class amphenicol used for the treatment of bacterial infections in livestock, poultry, and aquaculture (animal farming). It inhibits protein synthesis. Ff is an analog of chloramphenicol, an amphenicol compound on the WHO essential medicine list that is used for the treatment of human infections. Due to the extensive usage of Ff in animal farming, zoonotic pathogens have developed resistance to this antimicrobial agent. There are numerous reports of resistance genes from organisms infecting or colonizing animals found in human pathogens, suggesting a possible exchange of genetic materials. One of these genes is floR, a gene that encodes for an efflux pump that removes Ff from bacterial cells, conferring resistance against amphenicol, and is often associated with mobile genetic elements and other resistant determinants. In this study, we analyzed bacterial isolates recovered in rural Thailand from patients and environmental samples collected for disease monitoring. Whole genome sequencing was carried out for all the samples collected. Speciation and genome annotation was performed revealing the presence of the floR gene in the bacterial genome. The minimum inhibitory concentration (MIC) was determined for Ff and chloramphenicol. Chromosomal and phylogenetic analyses were performed to investigate the acquisition pattern of the floR gene. The presence of a conserved floR gene in unrelated Acinetobacter spp. isolated from human bacterial infections and environmental samples was observed, suggesting multiple and independent inter-species genetic exchange of drug-resistant determinants. The floR was found to be in the variable region containing various mobile genetic elements and other antibiotic resistance determinants; however, no evidence of HGT could be found. The floR gene identified in this study is chromosomal for all isolates. The study highlights a plausible impact of antimicrobials used in veterinary settings on human health. Ff shares cross-resistance with chloramphenicol, which is still in use in several countries. Furthermore, by selecting for floR-resistance genes, we may be selecting for and facilitating the zoonotic and reverse zoonotic exchange of other flanking resistance markers between human and animal pathogens or commensals with detrimental public health consequences.

Validation of electrochemical device setup for detection of dual antibiotic drug release from hydrogel.

Due to antimicrobial resistance that occurs throughout the world, antibiotic-releasing hydrogel with at least two drugs that synergistically treat stubborn bacteria is preferable for infection prevention. Hydrogel can serve as a drug reservoir to gradually release drugs in a therapeutic window to effectively treat microorganisms with minimal side effects. The study and development of drug releasing hydrogels requires a reliable, straightforward, cost-effective, fast, and low labor-intensive drug detection technique. In this study, we validate the electrochemical technique and device setup for real-time determination of dual antibacterial drugs released from a hydrogel. Concentrations of two representative antibacterial drugs, tetracycline (TC) and chloramphenicol (CAP), were determined using square wave voltammetry (SWV) mode that yields the lower limit of detection at 2.5 µM for both drugs. Measurement accuracy and repeatability were verified by 36 known drug combination concentrations. Capability in long-term measurement was confirmed by the measurement stability which was found to last for at least 72 h. Stirring was revealed as one of the significant factors for accurate real-time detection. Real-time measurement was ultimately performed to demonstrate the determination of multiple drug releases from a drug releasing hydrogel and validated by high-performance liquid chromatography (HPLC). All the results support that the electrochemical technique with the proposed device design and setup can be used to accurately and simultaneously determine dual drugs that are released from a hydrogel in real-time.

Chloramphenicol-imprinted polychitosan bounded with carbon dots as fluorescent sensor, dispersive sorbent, and drug carrier.

Chitosan, an abundant natural polysaccharide, was conjugated with carbon dots (CDs) and self-polymerized with chloramphenicol (CAP) templates to synthesize CD-incorporated and molecularly CAP-imprinted polychitosan (CD-MIC). The CD-MIC was used for fluorescent sensing, dispersive sorption, and dosage release of CAP at different pH levels. The sphere of action mechanism, approved by emission and excitation fluorescence, UV-Vis absorption, and fluorescence lifetime measurements, regulated the fluorescence static quenching. By the Perrin model, the quenching extent was linearly correlated to CAP within 0.17 - 33.2 µM (LOD = 37 nM) at pH 7.0. With an imprinting factor of 3.1, the CD-MIC was more selective for CAP than CD, although it was less sensitive to CAP. The recoveries of 5.0 µM CAP from milk matrix were 95% (RSD = 2.3%) for CD-MIC probes and 62% (RSD = 4.5%) for CD. The Langmuir and pseudo-second-order models preferably described the isothermal and kinetic sorptions of CAP into the imprinted cavities in CD-MICs, respectively. The Weber - Morris kinetic model showed three stages involved in intraparticle diffusion, which was pH-dependent and gradually arduous at the later stage, and showed external diffusion partly engaged in the diffusion mechanism. The 20 - 70% of CAP formulated in CAP-embedded CD-MICs were released in 8 - 48 h. The release percentage was lower at pH 7.0 than at pH 5.0 and 9.0, but the equilibrium time was shorter. At pH 7.0, the release percentage reached 45% at 10 min and slowly increased to 51% at 24 h.

In vitro determination of the susceptibility of Malassezia furfur biofilm to different commercially used antimicrobials.

Malassezia furfur is a yeast known as the etiological agent of seborrheic dermatitis. We evaluated the action of five different antimicrobials (amphotericin B, chloramphenicol, ketoconazole, fluconazole, and nystatin) on inhibiting biofilm formation and removing biofilm already formed by M. furfur. The assays were carried out using the microdilution method, and scanning electron microscopy images were used to analyze the biofilm structure. According to the results obtained, the percentage of inhibition was higher for chloramphenicol, followed by ketoconazole, nystatin, and amphotericin B. Regarding the eradication of the biofilm formed, the highest percentage was chloramphenicol, followed by ketoconazole and nystatin. Amphotericin B did not affect biofilm eradication, whereas fluconazole did not cause significant changes inhibiting or removing M. furfur biofilm. Therefore, except for fluconazole, all evaluated antimicrobials had inhibiting effects on the biofilm of M. furfur, either in its formation and/or eradication. Although the results achieved with chloramphenicol have been highlighted, further in vitro and in vivo studies are still needed in order to include this antimicrobial in the therapy of seborrheic dermatitis due to its toxicity, especially to the bone marrow.

Obtaining New Biocompatible Composite Materials with Antibacterial Properties Based on Diatomite and Biologically Active Compounds.

This study aimed to create new composite materials based on diatomite-a non-organic porous compound-through its surface modification with bioactive organic compounds, both synthetic and natural. Chloramphenicol, tetrahydroxymethylglycoluril and betulin were used as modifying substances. Composite materials were obtained by covering the diatomite surface with bioactive substance compounds as a solution and material dispersion in it. The materials were characterized by IR spectroscopy, SEM and X-ray photoelectron spectroscopy. For the biocomposites, the hemolytic effect, plasma proteins' adsorption on the surface and the antibacterial activity of the obtained materials were studied. Results show that the obtained materials are promising for medicine and agriculture.

Ultrasensitive detection of chloramphenicol in water using functionalized polymers with an aluminium organic framework.

Metal-Organic Frameworks (MOFs) are extensively used as electrode material in various sensing applications due to their efficacious porous nature and tunable properties. However, pristine MOFs lack conductive attributes that hinder their wide usage in electrochemical applications. Electropolymerization of several aromatic monomers has been a widely used strategy for preparing conducting electrode materials for various sensing applications in the past decades. Herein, we report a similar approach by employing the electropolymerization method to create a functional polymer layer to enhance the sensitivity of an Aluminium Organic Framework (DUT-4) for the selective detection of Chloramphenicol (CAP) antibiotic in aqueous environment. The combined strategy using the conducting polymer layer with the porous Al MOF provides surpassing electrochemical performance for sensing CAP with regard to the very low detection limit (LOD = 39 nM) and exceptionally high sensitivity (11943 µA mM-1 cm-2). In addition, the fabricated sensor exhibited good selectivity, reproducibility and stability. The developed method was successfully evaluated in various real samples including lake water and river water for CAP detection with good recovery percentages even at lower concentrations.

Nanomaterials Based on 2,7,12,17-Tetra-tert-butyl-5,10,15,20-tetraaza-21H,23H-porphine Exhibiting Bifunctional Sensitivity for Monitoring Chloramphenicol and Co2.

Monitoring antibiotic retention in human body fluids after treatment and controlling heavy metal content in water are important requirements for a healthy society. Therefore, the approach proposed in this study is based on developing new optical sensors using porphyrin or its bifunctional hybrid materials made with AuNPs to accomplish the accurate detection of chloramphenicol and cobalt. To produce the new optical chloramphenicol sensors, 2,7,12,17-tetra-tert-butyl-5,10,15,20-tetraaza-21H,23H-porphine (TBAP) was used, both alone in an acid medium and as a hybrid material with AuNPs in a water-DMSO acidified environment. The same hybrid material in the unchanged water-DMSO medium was the sensing material used for Co2+ monitoring. The best results of the hybrid materials were explained by the synergistic effects between the TBAP azaporphyrin and AuNPs. Chloramphenicol was accurately detected in the range of concentrations between 3.58 × 10-6 M and 3.37 × 10-5 M, and the same hybrid material quantified Co2+ in the concentration range of 8.92 × 10-5 M-1.77 × 10-4 M. In addition, we proved that AuNPs can be used for the detection of azaporphyrin (from 2.66 × 10-5 M to 3.29 × 10-4 M), making them a useful tool to monitor porphyrin retention after cancer imaging procedures or in porphyria disease. In conclusion, we harnessed the multifunctionality of this azaporphyrin and of its newly obtained AuNP plasmonic hybrids to detect chloramphenicol and Co2+ quickly, simply, and with high precision.