Functionalization of gold nanoparticles by β-cyclodextrin as a probe for the detection of heavy metals in water and photocatalytic degradation of textile dye

Gold nanocomposites in colorectal cancer therapy: characterization, selective cytotoxicity, and migration inhibition

The third most prevalent type of cancer in the world, colorectal cancer, poses a significant treatment challenge due to the nonspecific distribution, low efficacy, and high systemic toxicity associated with chemotherapy. To overcome these limitations, a targeted drug delivery system with a high cytotoxicity against cancer cells while maintaining a minimal systemic side effects represents a promising therapeutic approach. Therefore, the aim of this study was to develop an efficient gold nanocarrier for the targeted delivery of the anticancer agent everolimus to Caco-2 cells. A novel gold nanocomposite (EV-β-CD-HA-Chi-AuNCs) functionalized with a targeting ligand (hyaluronic acid), a permeation enhancement excipient (chitosan), and an anticancer inclusive compound consisting of beta-cyclodextrin and everolimus was proposed and prepared via Turkevich method. Characterization was performed with a UV spectrometer, FTIR, Zetasizer, and HRTEM. Its drug release profile was also evaluated in media with three different pH values. Cytotoxicity and biocompatibility studies were performed on a colorectal cancer cell line (Caco-2) and a normal fibroblast line (MRC-5), respectively, via xCELLigence real-time cellular analysis (RTCA) technology. The inhibitory effect on migration was also further tested via the xCELLigence RTCA technique and a scratch assay. Characterization studies revealed the successful formation of EV-β-CD-HA-Chi-AuNCs with a size and charge which are suitable for the use as targeted drug delivery carrier. In the cytotoxic study, the EV-β-CD-HA-Chi-AuNCs showed a lower IC50 (16 ± 1 µg/ml) than the pure drug (25 ± 3 µg/ml) toward a colorectal cell line (Caco-2). In the biocompatibility study, the EV-β-CD-HA-Chi-AuNCs have minimal toxicity, while the pure drug has severe toxicity toward healthy fibroblasts (MRC-5) despite its low concentration. In the cell migration study, the EV-β-CD-HA-Chi-AuNCs also showed a greater inhibitory effect than the pure drug. Compared with the pure drug, the EV-β-CD-HA-Chi-AuNCs exhibit an excellent selective cytotoxicity between cancerous colorectal Caco-2 cells and healthy MRC-5 cells, making it a potential carrier to carry the drug to the cancerous site while maintaining its low toxicity to the surrounding environment. In addition, an increase in the cytotoxic activity of the EV-β-CD-HA-Chi-AuNCs toward cancerous colorectal Caco-2 cells was also observed, which can potentially improve the treatment of colorectal cancer.

Exploring the anticancer and antioxidant potential of gold nanoparticles synthesized from Pterocarpus marsupium bark extract against oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a disease of significant concern with higher mortality rates. Conventional treatment approaches have several drawbacks, leading to the opening of new research avenues in the field of nanoparticle-based cancer therapeutics. The study aimed at the synthesis of gold nanoparticles (Pm-AuNPs) from the aqueous bark extract of Pterocarpus marsupium, followed by its characterization and in vitro anticancer evaluation against OSCC. The synthesized Pm-AuNPs were characterized using UV-visible spectroscopy, particle size analyser, zeta potential, FTIR and SEM techniques. The anticancer potential of the Pm-AuNPs was evaluated against OSCC cell lines (SCC29b, SSC154 and OECM-1) through in vitro assays. The IC50 value was found to be 25 ± 1.2, 45 ± 1.5 and 75 ± 2.1 µg/mL for the three OSCC cell lines, elucidating Pm-AuNPs cytotoxic effects and mechanism of action. Intracellular ROS and SOX detection, mitochondrial transmembrane potential analysis and apoptosis detection were used to confirm the activity of Pm-AuNPs against OSCC. Acute toxicity studies on Wistar rats confirmed the non-toxic nature of the Pm-AuNPs at a higher dose concentration up to 2000 mg/kg body weight. The findings underscore Pm-AuNPs as promising candidates for future anticancer therapeutics, providing insights into their mechanism of action and therapeutic efficacy against OSCC.

Synthesis of β-Cyclodextrin@gold Nanoparticles and Its Application on Colorimetric Assays for Ascorbic Acid and Salmonella Based on Peroxidase-like Activities

The peroxidase-like behaviors of gold nanoparticles (AuNPs) have the potential to the development of rapid and sensitive colorimetric assays for specific food ingredients and contaminants. Here, using NaBH4 as a reducing agent, AuNPs with a supramolecular macrocyclic compound β-cyclodextrin (β-CD) capped were synthesized under alkaline conditions. Monodispersal of β-CD@AuNPs possessed a reduction in diameter size and performed great peroxidase-like activities toward both substrates, H2O2 and TMB. In the presence of H2O2, the color change of TMB oxidization to oxTMB was well-achieved using β-CD@AuNPs as the catalyst, which was further employed to develop colorimetric assays for ascorbic acid, with a limit of detection as low as 0.2 μM in ddH2O. With the help of the host-guest interaction between β-CD and adamantane, AuNPs conjugated with nanobodies to exhibit peroxidase-like activities and specific recognition against Salmonella Typhimurium simultaneously. Based on this bifunctional bioprobe, a selective and sensitive one-step colorimetric assay for S. Typhimurium was developed with a linear detection from 8.3 × 104 to 2.6 × 108 CFU/mL and can be provided to spiked lettuce with acceptable recoveries of 97.31% to 103.29%. The results demonstrated that the excellent peroxidase-like behaviors of β-CD@AuNPs can be applied to develop a colorimetric sensing platform in the food industry.

Selective and Accurate Detection of Nitrate in Aquaculture Water with Surface-Enhanced Raman Scattering (SERS) Using Gold Nanoparticles Decorated with β-Cyclodextrins

A surface-enhanced Raman scattering (SERS) method for measuring nitrate nitrogen in aquaculture water was developed using a substrate of β-cyclodextrin-modified gold nanoparticles (SH-β-CD@AuNPs). Addressing the issues of low sensitivity, narrow linear range, and relatively poor selectivity of single metal nanoparticles in the SERS detection of nitrate nitrogen, we combined metal nanoparticles with cyclodextrin supramolecular compounds to prepare a AuNPs substrate enveloped by cyclodextrin, which exhibits ultra-high selectivity and Raman activity. Subsequently, vanadium(III) chloride was used to convert nitrate ions into nitrite ions. The adsorption mechanism between the reaction product benzotriazole (BTAH) of o-phenylenediamine (OPD) and nitrite ions on the SH-β-CD@AuNPs substrate was studied through SERS, achieving the simultaneous detection of nitrate nitrogen and nitrite nitrogen. The experimental results show that BTAH exhibits distinct SERS characteristic peaks at 1168, 1240, 1375, and 1600 cm-1, with the lowest detection limits of 3.33 × 10-2, 5.84 × 10-2, 2.40 × 10-2, and 1.05 × 10-2 μmol/L, respectively, and a linear range of 0.1-30.0 μmol/L. The proposed method provides an effective tool for the selective and accurate online detection of nitrite and nitrate nitrogen in aquaculture water.

β-Cyclodextrin capped ZnS nanoparticles for CER-assisted colorimetric and spectrophotometric detection of Pb2⁺, Cu2⁺, and Hg2⁺ in an aqueous solution

Herein, simple, low-cost, and room-temperature synthesis of beta-cyclodextrin (β-CD) stabilized zinc sulfide nanoparticle (ZnS NP) through the chemical precipitation method has been reported for cation exchange reaction (CER) based colorimetric sensing of Pb2+, Cu2+, and Hg2+. Formation of β-CD stabilized ZnS NPs (ZnS@β-CD) was verified by physicochemical characterization techniques such as XRD, XPS, FE-SEM, and TEM. ZnS@β-CD NPs showed color change selectively for the metal ions Pb2⁺, Cu2⁺, and Hg2⁺ among the various metal ions including Sn2⁺, Cr³⁺, Mn2⁺, Fe³⁺, Co2⁺, Ni2⁺, and Cd2⁺. The solubility product of reactants and the transformed products are the reason for selective CER of ZnS@β-CD NPs towards Pb2⁺, Cu2⁺, and Hg2⁺ ions. ZnS@β-CD NPs dispersion revealed rapid color change from white to orange, black, and bright yellow on the addition of higher concentrations of Pb2⁺, Cu2⁺, and Hg2⁺ respectively. This color change is due to the formation of complete CER-transformed nanostructures such as PbS, CuS, and HgS in higher concentrations (10⁻1- 10⁻³ M) of corresponding metal ions. The partial CER altered products Zn1-x,PbxS, Zn1-xCuxS and Zn1-xHgxS were detected due to the appearance of pale color in the lower metal ions concentrations of 10⁻⁴ - 10⁻⁶ M. This CER assisted transformation was also monitored through spectrophotometric methods. Moreover, infrared spectroscopic analysis was used to testify the structure of CER transformed product. The synthesized ZnS@β-CD NPs act as an efficient CER-based sensor for distinguishing and determining Pb2⁺, Cu2⁺, and Hg2⁺ at different level concentrations in the aqueous solution.

Microwave assisted hydrothermally synthesized cobalt doped zinc ferrites nanoparticles for the degradation of organic dyes and antimicrobial applications

A novel photocatalyst based cobalt doped zinc ferrites nanoparticles (Co-ZnFe₂O₄ NPs) was prepared to actively concentrate degradation of organic dyes in water. The aim this study is to investigate the effect of substitution of Co²⁺ for Zn²⁺ in zinc ferrites nanoparticles and is characterized with UV-visible spectroscopy, XRD, TEM, SEM, Photoluminescence and Vibrating sample magnetometer technique. When the calcinations temperature increases from 150 °C to 450 °C the amorphous ferrites begins to vanish and the characteristic reflections of cubic spinal Co-ZnFe₂O₄ phase are only observed at 450 °C. The band gap energy (E_g) of sample calcined at 250 °C is calculated at 5.2 eV and that of 450 °C is 4.5 eV. The observed value of band gap energy decreased with increasing calcinations temperature in the samples. The increase in PL peak intensity is due to collective emissions and light-scattering. The doping material, cobalt substitution at spinel zinc ferrites surface, and hence gradually decrease the amorphous effect, increase the saturation magnetization and decrease the coercivity while increasing the temperature. The compounds calcined at 250 °C and 450 °C were investigated for their in vitro antimicrobial activity against Staphylococcus aureus. A sample with 450 °C calcination temperature leads to higher efficiencies in the inhibition of growth of bacteria and degradation of organic dyes. Hence, this study provides a novel photocatalyst of Co-ZnFe₂O₄ NPs in the tile to degrade and analyze the environmentally ignored organic compounds.

UV light assisted photocatalytic degradation of textile waste water by Mg0.8-xZnxFe2O4 synthesized by combustion method and in-vitro antimicrobial activities

In this paper, Magnesium Zinc Ferrite (MZF) nanoparticles (Mg0.8-xZnxFe2O4, where x = 0.2, 0.4 and 0.6) are successfully fabricated by combustion process. The prepared nanoparticles are characterized through XRD, FTIR, UV, SEM, EDS and TEM. It has been confirmed that the samples produced cubic spinel structure with crystal size in the range of 13-15 nm. From the ultraviolet spectrum, the optical band gap is calculated which ranges from 5.6 to 4.6 eV. TEM micrographs confirm the nanocrystalline nature of combustion derived ferrite nanoparticles with average particle diameter of 7-28 nm. Antibacterial studies confirmed that the nanoparticles are toxic to Pseudomonas aeruginosa consists of greatest zone of inhibition of 25 mm. The antibacterial and photocatalytic studies exhibited improved activity which is strongly influenced by the zinc doping. Photocatalytic degradation study reveal that the prepared nanoparticles function as perfect catalyst for degradation of Methylene Blue (MB) dye and Textile Dyeing Waste Water (TDWW) under UV light, thus revealing their potential usage on organic pollutants.

Recent advances in the targeted delivery of paclitaxel nanomedicine for cancer therapy

Cancer cases have reached an all-time high in the current era.

Metal nanoparticles and its application on phenolic and heavy metal pollutants

The perpetual exposure of several manmade materials and their activities such as urbanization, industrialization, transportation, mining, construction, petroleum refining, manufacturing, preservatives, disinfectants etc., release various pollutants like organic, inorganic, and heavy metals which pollute the air, water, and soil. This poses various environmental issues which are relevant to the ecosystem and human wellbeing that intensify the implementation of new expedient treatment technologies. Likewise, phenolic and heavy metal pollutants find their way into the environment. These phenolic and heavy metals are toxic to the liver, heart and carcinogenic. Therefore, the removal of these kinds of pollutants from the environment is a highly challenging issue. As conventional treatment technologies have consequent drawbacks, new interests have been developed to remediate and remove pollutants from the ecosystem using metal nanoparticles (MPNs). To date, many researchers all over the world have been investigating novel approaches to enhance various remediation application technologies. One such approach that the researchers are constantly showing interest in is the use of nanomaterials with potential applications towards the environment. In this regard, MPNs like Copper (Cu), Nickel (Ni), Palladium (Pd), Gold (Au), Silver (Ag), Platinum (Pt), Titanium (Ti), and other nano metals are serving as a suitable agent to eliminate emerging contaminants in various fields, particularly in the removal of phenolic and heavy metal pollutants. This chapter discusses the mechanism and application of various MPNs in eliminating various phenolic and heavy metal pollutants from the environment.