Conversion of PET Bottle Waste into a Terephthalic Acid-Based Metal-Organic Framework for Removing Plastic Nanoparticles from Water.

Micro- and nanoparticles of plastic waste are considered emerging pollutants with significant environmental and health impacts at high concentrations or prolonged exposure time. Here we report the synthesis and characterization of a known metal-organic framework (MOF) using terephthalic acid (TPA) recovered from the hydrolysis of polyethylene terephthalate (PET) bottle waste. This approach adds value to the existing large amounts of bottle waste in the environment. Fully characterized zinc-TPA MOF (MOF-5) was used for the extraction and removal of engineered polyvinyl chloride (PVC) and polymethylmethacrylate (PMMA) nanoparticles from water with a high efficiency of 97% and 95%, respectively. Kinetic and isotherm models for the adsorption of polymer nanoparticles (PNPs) on the MOF surface were investigated to understand the mechanism. The Qmax for PVC and PMMA NPs were recorded as 56.65 mg/g and 33.32 mg/g, respectively. MOF-5 was characterized before and after adsorption of PNPs on the surface of MOF-5 using a range of techniques. After adsorption, the MOF-5 was successfully regenerated and reused for the adsorption and removal of PNPs, showing consistent results for five adsorption cycles with a removal rate of 83-85%. MOF-5 was characterized before and after adsorption of PNPs on the surface using a range of techniques. The MOF-5 with PNPs on the surface was successfully regenerated and reused for the adsorption and removal of polymer nanoparticles, showing consistent results for five extraction cycles. As a proof of concept, MOF-5 was also used to remove plastic particles from commercially available body scrub gel solutions. Such methods and materials are needed to mitigate the health hazards caused by emerging micro- and nanoplastic pollutants in the environment.

Purification of Intramineral Peptides from Cuttlebones and In Vitro Activity in CaCO3 Biomineralization.

Living organisms develop functional hard structures such as teeth, bones, and shells from calcium salts through mineralization for managing vital functions to sustain life. However, the exact mechanism or role of biomolecules such as proteins and peptides in the biomineralization process to form defect-free hierarchical structures in nature is poorly understood. In this study, we have extracted, purified, and characterized five major peptides (CBP1-CBP5) from the soluble organic materials (SOMs) of cuttlefish bone (CB) and used for the in vitro mineralization of calcium carbonate crystals. The SOMs induced nucleation of the calcite phase at low concentrations and the vaterite phase at high concentrations. The purified peptides nucleated calcite crystals and enhanced aggregation under laboratory conditions. Among five peptides, only CBP2 and CBP3 showed concentration-dependent nucleation, aggregation, and morphological changes of the calcite crystals within 12 h. Circular dichroism studies showed that the peptides CBP2 and CBP3 are in alpha helix and ß-sheet conformation, respectively, in solution. CBP1 and CBP4 and CBP5 are in random coil and ß-sheet conformation, respectively. In addition, the peptides showed different sizes in solution in the absence (∼27 nm, low aggregation) and presence (∼118 nm, high aggregation) of calcium ions. Aragonite crystals with needle-type morphologies were nucleated in the presence of Mg2+ ions in solution. Overall, exploring the activities of such intramineral peptides from CB help to unravel the mechanism of calcium salt deposition in nature.

Understanding the biological impact of organic pollutants absorbed by nanoplastics.

Many organisms are consuming food contaminated with micro- and nanoparticles of plastics, some of which absorb persistent organic pollutants (POPs) from the environment and acting as carrier vectors for increasing the bioavailability in living organisms. We recently reported that polymethylmethacrylate (PMMA) nanoparticles at low concentrations are not toxic to animal models tested. In this study, the toxicity of diphenylamine (DPA) incorporated PMMA nanoparticles are assessed using barnacle larvae as a model organism. The absorption capacity of DPA from water for commercially available virgin PMMA microparticles is relatively low (0.14 wt%) during a 48 h period, which did not induce exposure toxicity to barnacle nauplii. Thus, PMMA nanoparticles encapsulated with high concentrations of DPA (DPA-enc-PMMA) were prepared through a reported precipitation method to achieve 40% loading of DPA inside the particles. Toxicity of DPA-enc-PMMA nanoparticles were tested using freshly spawned acorn barnacle nauplii. The observed mortality of nauplii from DPA-enc-PMMA exposure was compared to the values obtained from pure DPA exposure in water. The mortality among the exposed acorn barnacle nauplii did not exceed 50% even at a high concentration of DPA inside the PMMA nanoparticles. The results suggest that the slow release of pollutants from polymer nanoparticles may not induce significant toxicity to the organism living in a dynamic environment. The impact of long-term exposure of DPA absorbed plastic nanoparticles need to be investigated in the future.

Black cardamom (Amomum subulatum Roxb.) fruit extracts exhibit apoptotic activity against lung cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried fruits of Amomum subulatum Roxb. (A. subulatum) are widely used as a spice. It is a part of official ayurvedic formulations used in folklore medicine to treat cancer.A. subulatum has been used in ayurvedic formulations to treat various lung conditions such as cough, lung congestion, pulmonary tuberculosis. The present traditional knowledge highlights the effectiveness of A. subulatum in treating cancer and its lung-specific efficacy. AIM OF THE STUDY: This study aims to investigate the cytotoxic potential of A. subulatum on the phenomenal and mechanistic level of lung cancer cells and identify the presence of A. subulatum actives. MATERIALS AND METHODS: The bioactivity of the extracts was tested using MTT assay, apoptotic assay, cell cycle analysis, superoxide production assay, reactive oxygen species (ROS) assay, and western blot analysis. Firstly, five different extracts were prepared using sequential extraction, and then screening of cell lines was performed using MTT assay. RESULTS: Lung cancer cells were selected as the most sensitive target, and dichloromethane extract (DE) was the most active extract. Annexin assay confirmed the mode of cell death as apoptosis. SubG1 peak found in cell cycle analysis substantiated this finding. ROS generation and superoxide showed association with apoptotic death. The upregulation and overexpression of cleaved poly(ADP-ribose)polymerase-1 (PARP-1) showed the failure of DNA repairing machinery contributes to apoptosis. LC-MS findings show the presence of cytotoxic actives cardamonin and alpinetin. CONCLUSIONS: In summary, this study shows the apoptosis-inducing potential of A. subulatum fruit extracts and confirms DNA damage as one of the causes of cell death. Further explorations using bio-fractionation and in-vivo studies are required to determine the most active constituents in A. subulatum.

Effect of Polymer Nano- and Microparticles on Calcium Carbonate Crystallization.

Molecular and macromolecular templates are known to affect the shape, size, and polymorph selectivity on the biomineralization of calcium carbonate (CaCO3). Micro- and nanoparticles of common polymers present in the environment are beginning to show toxicity in living organisms. In this study, the role of plastic nanoparticles in the biomineralization of CaCO3 is explored to understand the ecological impact of plastic pollution. As a model study, luminescent poly(methyl methacrylate) nanoparticles (PMMA-NPs) were prepared using the nanoprecipitation method, fully characterized, and used for the mineralization experiments to understand their influence on nucleation, morphology, and polymorph selectivity of CaCO3 crystals. The PMMA-NPs induced calcite crystal nucleation with spherical morphologies at high concentrations. Microplastic particles collected from a commercial face scrub were also used for CaCO3 nucleation to observe the nucleation of calcite crystals on the particle surface. Microscopic, spectroscopic, and X-ray diffraction data were used to characterize and identify the nucleated crystals. The data presented in this paper add more information on the impact of microplastics on the marine environment.

Comparison of Genotoxicity and Cytotoxicity of Polyvinyl Chloride and Poly(methyl methacrylate) Nanoparticles on Normal Human Lung Cell Lines.

High concentrations of micro- and nanoparticles of common plastic materials present in the environment are causing an adverse health impact on living organisms. As a model study, here we report the synthesis and characterization of luminescent polyvinyl chloride (PVC) and poly(methyl methacrylate) (PMMA) nanoparticles and investigate the interaction with normal human lung fibroblast cells (IMR 90) to understand the uptake, translocation, and toxicity of PVC and PMMA nanoparticles. The synthesized particles are in the size range of 120-140 nm with a negative surface potential. The colocalization and uptake efficiency of the nanoparticles were analyzed, and the cytotoxicity assay shows significant reduction in cell viability. Cellular internalization was investigated using colocalization and dynasore inhibitor tests, which showed that the PVC and PMMA nanoparticles enter into the cell via endocytosis. The polymer nanoparticles induced a reduction in viability, decrease in adenosine triphosphate, and increase in reactive oxygen species and lactate dehydrogenase concentrations. In addition, the polymer nanoparticles caused cell cycle arrest at sub-G1, G0/G1, and G2/M phases, followed by apoptotic cell death. Our results reported here are important to the emerging data on understanding the impact of common polymer particles on human health.

Understanding the interactions of poly(methyl methacrylate) and poly(vinyl chloride) nanoparticles with BHK-21 cell line.

Microplastic and nanoplastic particles are prevalent in the environment and are beginning to enter the living system through multiple channels. Currently, little is known about the impact of plastic nanoparticles in living organisms. In order to investigate the health impact of micro- and nanoparticles of common polymers in a systematic way, luminescent plastic nanoparticles from two common polymers, polyvinyl chloride (PVC) and poly (methyl methacrylate) (PMMA) with relatively narrow size distribution are prepared using a nanoprecipitation method. As a model system, BHK-21 cells were exposed to polymer nanoparticles to understand the mode of uptake, internalization and biochemical changes inside the cells. The cellular effects of the nanoparticles were evaluated by monitoring the changes in cell viability, cell morphology, concentrations of reactive oxygen species (ROS), adenine triphosphate (ATP) and lactate dehydrogenase at different concentrations of the nanoparticles and time of exposure. PVC and PMMA nanoparticles induced a reduction in the cell viability along with a reduction of ATP and increase of ROS concentrations in a dose- and time-dependent manner. The plastic nanoparticles are internalized into the cell via endocytosis, as confirmed by Dynasore inhibition assay and colocalization with latex beads. Our findings suggest that plastic nanoparticle internalization could perturb cellular physiology and affect cell survival under laboratory conditions.

Bioinspired adenine-dopamine immobilized polymer hydrogel adhesives for tissue engineering.

Nontoxic adhesive hydrogels are of great importance in tissue engineering. Herein, we report a simple synthesis of a few biocompatible hydrogels from adenine and dopamine immobilized polyacrylic acid (PAA) and alginic acid (Alg) polymers. The adenine-dopamine adduct incorporated hydrogels showed enhanced adhesiveness, transparency and biocompatibility, and induced cell proliferation in 2D and 3D-cell culture models within 24 h. Moreover, blending the modified PAA and Alg polymers (P2P4) further increased the stability and bioactivity of the hydrogel. Such biogels can be developed as smart materials for biomedical applications.