Applications of QSAR study in drug design of tubulin binding inhibitors.

New drug discovery is recognized as a complicated, costly, time-consuming, and difficult process. Computer-aided drug discovery has developed as a potent and promising method for faster, cheaper, and more effective drug creation. Recently, the rapid rise of computational methods for drug discovery, including anticancer medicines, had a substantial and exceptional impact on anticancer drug design, as well as providing beneficial insights into the field of cancer therapy. In this paper, we discussed the quantitative structure-activity relationship (QSAR), which is a significant in-silico tool in rational drug design. The QSAR method is used to optimize the existing leads to improve their biological activities, and physicochemical properties and to predict the biological activities of untested and sometimes unavailable compounds, so QSAR is a significant method in drug designing. This article is a comprehensive review of various QSAR studies conducted which help to create new and potent inhibitors for targeting tubulin, a crucial target in cancer treatment. It particularly focuses on studies that provide structural insights into the compounds targeting tubulin. It should prioritize continually researching specific scaffolds, with a focus on important attachment regions, to gather more powerful molecular data and enhance models. This will lead to a better understanding of drug interactions and the development of improved cancer-targeting inhibitors for tubulin.Communicated by Ramaswamy H. Sarma.

Synthesis and characterization of PANI-ZrWPO4 nanocomposite: adsorption-reduction efficiency and regeneration potential for Cr(VI) removal.

A novel polyaniline zirconium tungstophosphate (PANI-ZrWPO4) nanocomposite was successfully synthesized through an in situ oxidative polymerization reaction followed by a microwave irradiation process. The synthesized nanocomposite was characterized by using FESEM, EDX, TEM, XRD, FTIR, Raman, TGA-DTA, XPS, and N2 adsorption-desorption analysis and chemical analysis to know about the formation of material. The results of the FTIR and Raman spectra confirmed that the conducting PANI polymer interacted with ZrWPO4 to form the PANI-ZrWPO4 nanocomposite. The XRD data showed that the composite had a crystalline nature. The TEM and FESEM images revealed that polyaniline had formed on the exterior of the PANI-ZrWPO4 nanocomposite. Further investigation was done on the efficiency of the PANI-ZrWPO4 nanocomposite as an adsorbent for Cr(VI) removal through batch adsorption experiments. The maximum Langmuir adsorption capacity of PANI-ZrWPO4 was found to be 71.4 mg g-1. The removal of Cr(VI) was optimized with the six variables namely adsorbent dose, initial concentration, Time, pH, Temperature, and stirring rate using the Box-Behnken design (BBD) model. The XPS spectra confirmed simultaneously adsorption reduction occurs Cr(VI) to Cr(III) through in situ chemical reduction. Moreover, the regeneration efficiency of PANI-ZrWPO4 was studied, and it was found to be able to remove around 80% of Cr(VI) even after five cycles, demonstrating its potential as an effective and reusable adsorbent.

In silico homology modeling, docking and sequence analysis of some bacterial laccases to unravel enzymatic specificity towards lignin biodegradation.

Laccase is a delignifying enzyme that belongs to the oxidoreductase family, and it has long been investigated as a pretreatment agent in biofuel production. In this study, amino acid sequences of five bacterial laccases from Bifidobacterium breve, Klebsiella pneumonia, Pseudodesulfovibrio hydrargyri, Pseudomonas aeruginosa and Veillonella rodentium have been retrieved from UniProtKB for sequence alignment, phylogenetic analysis using MEGA 7.0 and 3 D structure prediction by homology modeling in SWISS-MODEL. Multiple sequence alignment between all the bacterial laccase sequences revealed a similar structural fold, although the overall protein sequence varied greatly with the substrate binding sites. Further molecular docking in AutoDock Vina and MD stimulation (MDS) in GROMACS for those modelled enzymes were performed considering both apo and ligand bound structures considering both apo and its ligand bound form. Investigation of molecular interaction utilizing docking of five bacterial laccases with three substrates (ABTS, DMP and Guaiacol) revealed that ABTS with K. pneumoniae laccase had the highest binding energy of -7.00 kcal/mol. In the current MDS investigation, bacterial laccases demonstrated greater binding and substrate energy in the ligand bound complex than in the apo form for ABTS, DMP and Guaiacol. In most cases of bacterial laccase, MDS revealed that DMP bound complex was more stable within an average RMSD value lower than 0.5 nm throughout 100 ns time scale. Thus, in silico studies undertaken in this work will be useful in determining the stable enzyme-substrate complex which further might improve the enzymatic catalysis of bacterial laccases for lignin breakdown and biofuel generation.

Anti-SARS-CoV-2 antibodies among vaccinated healthcare workers: Repeated cross-sectional study.

Background: Since the novel SARS-CoV-2 has been detected and the ensuing pandemic, the search for a cure or prevention has been the only target of the medical fraternity. As the second wave racked havoc, vaccines seemed to be the only viable option to stop this global surge. World Health Organization (WHO) and subsequently the Government of India have issued emergency use authorization to two vaccines. Our study aims to estimate the prevalence of the anti-SARS-CoV-2 antibodies and identify predictors of antibody titers in vaccinated healthcare workers in VIMSAR, Burla. Methods: This is a part of the ongoing, repeated cross-sectional study. Participants were enrolled well above the sample size (322) to increase precision. Two rounds of the survey were conducted and are being reported. Serum IgG antibodies against spike protein of SARS-CoV-2 were estimated using Elecsys® anti-SARS-CoV-2S is an immunoassay by ECLIA-based Cobas e411 analyzer. Univariate and multivariate regression were used in statistical analysis. Results: Our results show that 95.1% and 99.5% of the vaccinated individuals have developed antispike protein antibodies after the first and second doses, respectively. Previous COVID-19 infection was significantly correlated with antibody production, and age was negatively correlated. No difference was reported for sex, occupation, and diabetes. Conclusion: Our interim analysis report is coherent with the available literature and research regarding the high efficacy of the COVID-19 vaccine as far as seroconversion is concerned.

Polymer-Induced Emission-Active Fluorine-Embedded Carbon Dots for the Preparation of Warm WLEDs with a High Color Rendering Index.

Exploration of many strategies has continuously contributed to producing aggregation-induced red-emissive carbon dots (CDs). In this work, we designed fluorine-embedded (F-embedded) CDs from 1,2,4-triaminobenzene, thiourea, and ammonium fluoride (NH4F) exhibiting polymer-induced emission (PIE). The PIE phenomenon of fluorescent CDs is obtained in poly(vinyl alcohol) (PVA), showing emissions at 611 and 617 nm in the dispersed and solid states, respectively. The CDs exhibited a red shift of 28 nm in the PVA solution because PVA hydroxyl groups formed a robust bridge-like H-bonding network between CDs. The fluorine embedded in CDs enhanced the H-bond affinity toward PVA. It showed that this H-bond restricted the coupling of CDs' surface states and inhibited the nonirradiation transfer. For the solid state, surface PVA chains eliminated the π-π interaction of the conjugated core and constructed a self-quenching resistance polymeric system around CDs. As a result, CDs showed an unexpected red shift of fluorescence emission in PVA. Furthermore, white light-emitting diodes (WLEDs) have a correlated color temperature (CCT) of 5232 K, and a high color rendering index of 95 has been fabricated by integrating the red- and green-emissive films over the UV LEDs. Interestingly, the as-synthesized CDs showed room temperature phosphorescence (RTP), which enabled us to employ the CDs in double-security protection. Simultaneously, CDs have been used in fingerprint detection.

Investigating the selectivity and interference behavior for detoxification of Cr(VI) using lanthanum phosphate polyaniline nanocomposite via adsorption-reduction mechanism.

A novel Lanthanum phosphate polyaniline (LaPO4-PANI) nanocomposite was synthesized by the simple sol-gel technique. The nanocomposite prepared at 1:1 ratio provided the highest ion exchange capacity and selective adsorption of Cr(VI). The phase composition and particle morphology of the as-prepared material was evaluated by XRD, FESEM and TEM analyses. The FTIR, Raman, and TGA data inferred the definite chemical interaction between the organic and inorganic counterparts in the formation of LaPO4-PANI. The selective adsorption of Cr(VI) was estimated by evaluating the distribution coefficient, electrical double layer theory as well as valency and Pauling's ionic radii of interfering ions (phosphate, iodide, sulfate, chloride, sulfide). The high tolerance capability of LaPO4-PANI against the interfering ions made it appropriate for selective and efficient removal of Cr(VI) ions from solutions. The nanocomposite showed the highest removal percentage of 98.6% towards Cr(VI) in a wide pH range of 2-6 at room temperature, as compared to sole lanthanum phosphate (56%) and polyaniline (75%). The XPS analysis revealed the adsorption mechanism due to the combined effect of both adsorption and reduction. Cr(VI) is adsorbed through electrostatic interactions while the = N-/-NH- group facilitated the in situ chemical reduction. The procured results make the LaPO4-PANI nanocomposite a promising adsorbent for the removal of Cr(VI).

Visible light active Zr- and N-doped TiO2 coupled g-C3N4 heterojunction nanosheets as a photocatalyst for the degradation of bromoxynil and Rh B along with the H2 evolution process.

Herein, we drastically increased the l ight-harvesting abilities of TiO2 by creating a defect level with doping using zirconium (Zr) and nitrogen (N). Titanium was substantially replaced by Zr from its lattice point, and N was bound on the surface as (NO)x. The doped system comes with a reduced band edge of 2.8 eV compared to pure TiO2 (3.2 eV), and the doping was accompanied by a higher rate of recombination of photogenerated electron-hole pairs. A heterostructure was fabricated between the modified titania and g-C3N4 to efficiently separate the carriers. An easy and cost-effective sol-gel process followed by a co-calcination technique was used to synthesize the nanostructured composite. The optimum dopant concentration and the extent of doping were investigated via XRD, Raman, XPS, TEM, and PL analyses, followed by a photocatalytic study. The impact of the band positions was investigated via UV-DRS and EIS. The dynamic nature of the band alignment at the depletion region of the heterojunction increased the carrier mobility from the bulk to active sites. The photogenerated electrons and holes retained their characteristic redox abilities to generate both OH˙ and O2 -˙ through a z-scheme mechanism. The photocatalytic activity resulted in superior photocatalytic H2 evolution along with the defragmentation of bromoxynil, a persistent herbicide. The active catalyst exhibited 97% degradation efficiency towards pollutants along with 0.86% apparent quantum efficiency during the H2 evolution reaction.

Waning of Anti-spike Antibodies in AZD1222 (ChAdOx1) Vaccinated Healthcare Providers: A Prospective Longitudinal Study.

Introduction Coronavirus disease 2019 (COVID-19) vaccines are nothing short of a miracle story halting the pandemic across the globe. Nearly half of the global population has received at least one dose. Nevertheless, antibody levels in vaccinated people have shown waning, and breakthrough infections have occurred. Our study aims to measure antibody kinetics following AZD1222 (ChAdOx1) vaccination six months after the second dose and the factors affecting the kinetics. Materials and methods We conducted a prospective longitudinal study monitoring for six months after the second of two AZD1222 (ChAdOx1) vaccine doses in healthcare professionals and healthcare facility employees at Veer Surendra Sai Institute of Medical Sciences and Research (included doctors, nurses, paramedical staff, security and sanitary workers, and students). Two 0.5-mL doses of the vaccine were administered intramuscularly, containing 5 x 1010 viral particles 28 to 30 days between doses. We collected blood samples one month after the first dose (Round 1), one month after the second dose (Round 2), and six months after the second dose (Round 3). We tested for immunoglobulin G (IgG) levels against the receptor-binding domain of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by chemiluminescence microparticle immunoassay. We conducted a linear mixed model analysis to study the antibody kinetics and influencing factors. Results Our study included 122 participants (mean age, 41.5 years; 66 men, 56 women). The geometric mean IgG titers were 138.01 binding antibody units (BAU)/mL in Round 1, 176.48 BAU/mL in Round 2, and 112.95 BAU/mL in Round 3. Seven participants showed seroreversion, and 11 had breakthrough infections. Eighty-six participants showed a substantial decline in antibody titer from Rounds 2 to 3. Persons aged 45 or older had higher mean titer than people aged younger than 45 years. Overweight and obese (BMI ≥ 25 kg/m2) had a higher mean titer than average or underweight persons. The only significant predictor of IgG titers at six months was SARS-CoV-2 infection on mixed model analysis. Conclusion We found a substantial decline in antibody levels leading to seven cases of seroreversion in healthcare professionals who received the ChAdOx1 vaccine. History of prior COVID-19 was the only significant factor in antibody levels at six months. Seroreversion and breakthrough infection warrant further research into the optimal timing and potential benefits of booster doses of the AZD1222 (ChAdOx1) COVID-19 vaccine.

COVID-19 Lab: A Whistlestop Journey at a Tertiary Health Care Center.

Purpose Right now, our world is in the grip of the COVID-19 pandemic. The global spread of COVID-19 (SARS-CoV-2) has dramatically increased the number of suspected cases with an expanding geographical area. The rapid identification of asymptomatic and mildly symptomatic contacts is the priority for clinical management and outbreak control. Suspected cases should be screened for the virus with a nucleic acid amplification test (NAAT) such as real-time reverse transcriptase-polymerase chain reaction (RT-PCR) under the guidance of laboratory experts. Materials and methods This manuscript details the process of the establishment of a COVID-19 lab, which is a medical college virology lab (Viral Research Diagnostic Lab), in less than a months' time. Detailed data of the tests were studied over the initial one month and reported. Results Within one and a half months of the start of the lab, 3196 tests were conducted, which caters to five adjoining districts in Western Odisha. These included both symptomatic and asymptomatic cases (contacts with a travel history from affected areas), and six COVID-19 positive cases were detected. Conclusion Though the establishment of a COVID-19 lab in a short time is a challenge, it can be achieved through determination, teamwork, and support from the authorities.

Effect of Solvent-Derived Highly Luminescent Multicolor Carbon Dots for White-Light-Emitting Diodes and Water Detection.

Recently, the multicolor fluorescent carbon dots (CDs) have drawn much attention due to their various applications. Herein, we report multicolor emissive CDs by solvent-controlled and solvent-responded approaches. The blue to red color emissive CDs are obtained by the solvothermal method by varying the solvent during the reaction. The red color emissive CDs (R-CDs) with good quantum yield is obtained in a water medium. The detailed characterization revealed that the solvent controls the particle size, band gap, and nitrogen doping concentration. Specifically, in the protic solvent, the high N content and presence of imine nitrogen are the reason for red emission. However, in an aprotic solvent, the least N doping and a lack of C-O groups are responsible for a blueshift. Interestingly, it was observed that the R-CDs provide a full range of visible color by dispersing in different immiscible solvents. The fluorescence emission in immiscible solvents is redshifted by enhancing the polarity. Moreover, the developed CDs detected the low water concentrations (≤0.2%, v/v) visually and fluorometrically in various organic solvents. Simultaneously, we have employed synthesized CDs in white-light-emitting diodes and fluorescent ink.

Kendu (Diospyros melanoxylon Roxb) fruit peel activated carbon-an efficient bioadsorbent for methylene blue dye: equilibrium, kinetic, and thermodynamic study.

In this work, activated carbon was synthesized by the carbonization of kendu fruit peel followed by chemical activation using ammonium carbonate as an activating agent to get modified kendu fruit peel (MKFP). The SEM and FESEM images of the biomaterial illustrated a highly porous honeycomb-like structure, further supported by the N2 sorption isotherm analysis. The FTIR spectra specified the presence of oxygen-containing functional groups such as carboxyl, carbonyl, and hydroxyl on the adsorbent surface. Batch experiments were performed for the optimization of methylene blue (MB) dye removal. The adsorption process followed pseudo-second-order kinetic model and Langmuir isotherm model with a maximum adsorption capacity of 144.9 mg g-1. No desorption was found because the adsorbent surface was bonded with the chromophoric group of the MB dye by means of strong chemical interaction evident from the high adsorption energy (E = 10.42 kJ mol-1) and enthalpy change (∆H = 42.7 kJ mol-1). Hence, the MKFP has the potential to act as an efficient bioadsorbent for MB dye removal. Graphical abstract.

Facile synthesis of poly o-toluidine modified lanthanum phosphate nanocomposite as a superior adsorbent for selective fluoride removal: A mechanistic and kinetic study.

This work reports the synthesis of a new adsorbent material (LaP-POT), synthesised by sol-gel polymerisation method from lanthanum phosphate (LaP) and poly o-toluidine (POT). The sustainability and selectivity of the material as a potential adsorbent is evaluated for the removal of fluoride from aqueous as well as real water samples using batch experimental techniques. FESEM and TEM images showed the successful incorporation of rod-shaped lanthanum phosphate into the poly o-toluidine polymer matrix. The increased degradation temperature of LaP-POT from TGA curve inferred a definite interaction between two. XPS study revealed the successful binding of fluoride onto LaP-POT. The selectivity of fluoride ion onto LaP-POT material was ascertained by the distribution coefficient value. The co-anions showed little effect on fluoride removal. Kinetic study suggested that intraparticle diffusion is not the only rate controlling step; the external mass transfer or chemical interaction also impacts the fluoride adsorption. The maximum adsorption was observed at room temperature with a maximum Langmuir uptake capacity of 10.94 mg g-1. The reusability of the material is tested up to 5 successive cycles for a workable commercial application purpose. The results showed that LaP-POT provides more active sites, thus making it a promising adsorbent for the removal of fluoride.

Facile Strategy to Synthesize Magnetic Upconversion Nanoscale Metal-Organic Framework Composites for Theranostics Application.

Recently, the design of a theranostics system has involved increasing attention in the area of biomedical applications. In many cases, the intricate synthesis process of upconversion nanoparticle-based composite materials limits the use of theranostics applications. To address this challenge, a nanocomposite has been successfully fabricated by the conjugation of magnetic NaGdF4:Yb/Er nanoparticles as an imaging agent and MIL-53(Fe) as a drug carrier through a single step. Simultaneously, folic acid is encapsulated on the surface of the nanocomposite by conjugation chemistry to achieve the targeted drug delivery applications. The synthesized nanocomposite exhibits a sufficient amount of loading ability toward the model anticancer doxorubicin and possesses pH-responsive drug release. The functionalized nanocomposite not only possesses excellent colloidal stability and good magnetic and fluorescence property but also shows superior biocompatibility, strong tumor cell growth inhibitory effect, and cancer-enhanced cellular uptake. It is expected that the synthesized nanocomposite can also serve as a platform for both T1 and T2 MRI contrast agents.

In situ synthesized lactobionic acid conjugated NMOFs, a smart material for imaging and targeted drug delivery in hepatocellular carcinoma.

Development of multifunctional nanoscale materials for targeted drug delivery in liver tumor cells has been realized in this work. Recently, nanoscale metal organic frameworks (NMOFs) have been used as a potential drug carrier for its unique characteristic properties. Here we have demonstrated a single step approach for the fabrication of lactobionic acid (LA) modified NH2-MIL-53(Al) NMOFs via green synthetic process. The anticancer drug doxorubicin (DOX) is loaded for targeted delivery in hepatocellular carcinoma cell lines (HepG2). The LA-targeted NMOFs have no cytotoxicity in both normal and hepatocellular cell lines. Human hepatocellular carcinoma cell lines are enriched of asialoglycoprotein receptors and simultaneously LA has strong recognition ability towards this receptor. The MTT assay reveals the DOX loaded LA-embedded NMOFs show greater cytotoxicity towards HepG2 cell lines in compare to normal cell lines. The FACS study also indicates that DOX-loaded LA-targeted NMOFs show greater cell death than bare NMOFs. More importantly, the NH2-MIL-53 NMOFs possess inherent fluorescent property and also the fluorescence intensity remains unaltered after conjugation of LA. So, the developed LA-embedded multifunctional NMOFs have good therapeutic efficacy for cell imaging and targeted drug delivery.

Facile synthesis of carbon fiber reinforced polymer-hydroxyapatite ternary composite: A mechanically strong bioactive bone graft.

Carbon fiber reinforced carboxymethyl cellulose-hydroxyapatite ternary composites have been synthesized by a simple wet precipitation method for weight bearing orthopedic application. Composites were synthesized with the incorporation of chemically functionalized carbon fibers. The functional groups onto the surface of fibers induced the formation of hydroxyapatite at the bridging position through which fibers were effectively bound with matrix. Consequently, the flexural strength and compressive strength of composite have reached to 140 MPa and 118 MPa, respectively. The flexural modulus of the composite is in the range of 9-22 GPa. In-vitro cell study showed that the composite possesses excellent cell proliferation and differentiation ability. With these excellent mechanical and biological properties, synthesized composite exhibits potential to be used as a mechanically compatible bioactive bone graft.

Synthesis and characterization of magnetic bio-adsorbent developed from Aegle marmelos leaves for removal of As(V) from aqueous solutions.

A novel magnetic bio-adsorbent was prepared from the leaves of Aegle marmelos tree (Indian bael) and Fe2O3 nanoparticles. The AMP@Fe2O3 nanocomposite (Aegle marmelos leaf powder) was synthesized by pyrolysis process and applied for As(V) removal through batch adsorption process. The synthesized AMP@Fe2O3 nanocomposite was analyzed by several instrumental techniques like XRD, FESEM, TEM, HRTEM, FTIR, BET, and VSM studies. Maximum amount of As(V) was removed at pH 3, contact time of 250 min, adsorbent dose of 0.1 g/L, and initial concentration of 0.5 mg/L at room temperature. The model study revealed that the pseudo-second-order kinetics and Langmuir isotherm models were best fitted with the experimental data. The nanocomposite showed a maximum adsorption capacity of 69.65 mg/g. The endothermic nature of the adsorption process was ascertained from the thermodynamics studies. The zeta potential and FTIR analysis before and after adsorption demonstrated two types of adsorption mechanism. The first one was the electrostatic attraction between negatively charged As(V) ions (H2AsO4-) and protonated -OH group present on the Fe2O3 surface and the second one was ligand exchange between the surface hydroxyl groups and As(V) ions. The AMP@Fe2O3 nanocomposite was desorbed with 0.5 M NaOH solutions and also used up to four cycles without any major decrease in removal efficiency. Thus, AMP@Fe2O3 nanocomposite can be applied as a potential adsorbent for As(V) removal from wastewater.

IRMOF-3: A fluorescent nanoscale metal organic frameworks for selective sensing of glucose and Fe (III) ions without any modification.

The amine functionalized isoreticular metal-organic framework-3 (IRMOF-3) is synthesized by hydrothermal method. Till now, it's widely used in the area of gas separation, adsorption, and catalysis due to large surface area, structural stability, and tunability. Here, we have reported the use of fluorescent nanoscale IRMOF-3 for highly selective detection of glucose as well as Fe3+ ions without any modification. This is due to NH2 and COOH groups are present on the surface of IRMOF-3 to bind cis-diols of the glucose molecule via host-guest interaction, and Fe3+ ions via ligand to metal charge transfer. The Synthesized IRMOF-3 has average diameter of 160 ±â€¯20 nm and interestingly possess deep blue fluorescent emission spectra at 460 nm with quantum yield 17.3%. Using fluorometric assay, the limit of detection (LOD) of glucose and Fe3+ ions was found to be 0.56 µM and 4.2 nM respectively. More importantly, the synthesized IRMOF-3 is also utilized for detection of glucose and Fe3+ ions in bio-environmental samples.

Fabrication of a Hierarchical TiO2 Microsphere/Carbon Dots Photocatalyst for Oxygen Evolution and Dye Degradation Under Visible Light.

Anatase hierarchical TiO2 microsphere/carbon dots composite (HTM/CDs) was fabricated by a facile method for active visible light photocatalysis. The phase, morphology, microstructure and optical properties were investigated by X-ray diffraction, scanning electronmicroscopy, transmission electron microscopy and UV-VIS diffuse reflectance spectroscopy respectively. Under visible light illumination, the fabricated HTM/CDs composite was exhibited an enhanced photo catalytic activity compared to that of pure hierarchical TiO2 microspheres (HTM). Such an enhancement in photocatalytic activity can be attributed to an increase in the absorption of visible light. The photocatalytic activity was investigated by the degradation of a model dyemalachite green (MG) and oxygen production through water splitting.We believe that this type of hybrid material could be used as a highly active and stable visible light photocatalyst to remove pollutants as well as energy production with high performance.

One pot synthesis of carbon dots decorated carboxymethyl cellulose- hydroxyapatite nanocomposite for drug delivery, tissue engineering and Fe3+ ion sensing.

In this work, carbon dots conjugated carboxymethyl cellulose-hydroxyapatite nanocomposite has been synthesized by one-pot synthesis method and used for multiple applications like metal ion sensing, osteogenic activity, bio-imaging and drug carrier. The structure and morphology of the nanocomposite were systematically characterized by FTIR, XRD, TGA, FESEM, TEM and DLS. Results clearly demonstrated the formation of fluorescent enabled carbon dots conjugated nanocomposite from carboxymethyl cellulose-hydroxyapatite nanocomposite by a simple thermal treatment. The synthesized nanocomposite is smaller than 100 nm and exhibits fluorescence emission band around 440 nm upon excitation with 340 nm wavelength. In the meantime, the nanocomposite was loaded with a chemotherapeutic drug, doxorubicin to evaluate the drug loading potential of synthesized nanocomposite. Moreover, the as-synthesized nanocomposite showed good osteogenic properties for bone tissue engineering and also exhibited excellent selectivity and sensitivity towards Fe3+ ions.

Fabrication of nitrogen- and phosphorous-doped carbon dots by the pyrolysis method for iodide and iron(III) sensing.

A facile and novel strategy to synthesize nitrogen- and phosphorous-doped carbon dots (NPCDs) by single step pyrolysis method is described here. Citric acid is used as carbon source and di-ammonium hydrogen phosphate is used as both nitrogen and phosphorous sources, respectively. Through the extensive study on optical properties, morphology and chemical structures of the synthesized NPCDs, it is found that as-synthesized NPCDs exhibited good excitation-dependent luminescence property, spherical morphology and high stability. The obtained NPCDs are stable in aqueous medium and possess a quantum yield of 10.58%. In this work, a new assay method is developed to detect iodide ions using the synthesized NPCDs. Here, the inner filter effect is applied to detect the iodide ion and exhibited a wide linear response concentration range (10-60 µM) with a limit of detection (LOD) of 0.32 µM. Furthermore, the synthesized NPCDs are used for the selective detection of iron(III) (Fe3+ ) ions and cell imaging. Fe3+ ions sensing assay shows a detection range from 0.2 to 30 µM with a LOD of 72 nM. As an efficient photoluminescence sensor, the developed NPCDs have an excellent biocompatibility and low cytotoxicity, allowing Fe3+ ion detection in HeLa cells.