Photothermal effect and cytotoxicity of CuS nanoflowers deposited over folic acid conjugated nanographene oxide

Herein, we present the rational synthesis of a multimode photothermal agent, NGO-FA-CuS, for the advancement of photothermal therapy of cancer. The hierarchical architecture created in NGO-FA-CuS was attained by the covalent conjugation of folic acid (FA) to nanographene oxide (NGO) through amide bonding, followed by the hydrothermal deposition of CuS nanoflowers. In this approach, instead of mere mixing or deposition, FA was covalently bonded to NGO, which helped in retaining their intrinsic properties after binding and allowed to access them in the resulting hybrid nanostructure. In this specifically designed photothermal agent, NGO-FA-CuS, each component has an explicit task, i.e., NGO, FA and CuS act as the quencher, cancer cell-targeting moiety and photothermal transduction agent, respectively. Prior to the grafting of FA molecules and the deposition of CuS nanoflowers, sulfonic acid groups were introduced into NGO to provide stability under physiological conditions. Under irradiation using a 980 nm laser, NGO-FA-CuS was able to attain a temperature of 63.1 °C within 5 min, which is far beyond the survival temperature for cancer cells. Therefore, the resulting temperature recorded for NGO-FA-CuS was sufficient to induce hyperthermia in cancer cells to cause their death. When coming into contact with cancer cells, NGO-FA-CuS can cause a rapid increase in the temperature of their nucleus, destroy the genetic substances, and ultimately lead to exhaustive apoptosis under illumination using a near-infrared (NIR) laser. An excellent photothermal efficiency of 46.2% under illumination using a 980 nm laser and outstanding cytotoxicity against HeLa, SKOV3 and KB cells were attained with NGO-FA-CuS. Moreover, NGO-FA-CuS displays exceptional persistent photo-stability without photo-corrosiveness. The photothermal effect of NGO-FA-CuS was found to be dependent on its concentration and the power density of the laser source. It was found that its cytotoxicity toward cancer cells was enhanced with an increase in the concentration of NGO-FA-CuS and the incubation period.

Identification of Phytotoxic Levels of Copper and Nickel in Commercial Organic Soil Amendments Recycled from Poultry Farms and Municipal Wastes

Commercial-scale recycling of agricultural and municipal wastes into organic soil amendments facilitates safe disposal of waste and reduces environmental contamination. However, phytotoxicity of commercial organic amendments to crops is a major concern to farmers. Consistent with this, commercial chicken manure and Milorganite (recycled from municipal waste) were found to be phytotoxic. Chicken manure aqueous extract contains 10.8 ppm Cu and 0.7 ppm Ni. The level of Cu and Ni in Milorganite is lower. The current study identified an aqueous solution containing 5 ppm Cu, lower than in chicken manure aqueous extract, was highly phytotoxic to mustard seeds germination. Therefore, phytotoxicity of chicken manure is in part due to Cu. An aqueous solution containing 1 ppm Ni was not phytotoxic; whereas 0.125 ppm Ni was phytotoxic when 62.5 ppm Na, which is nontoxic, was added to the solution. Therefore, synergistic effects of chemicals in the organic amendments may induce phytotoxicity.

Synthesis and characterization of Zinc/Chitosan-Folic acid complex

Therapeutic drug delivery systems using polymeric materials is an emerging field of research. However, the use of certain polymers has gained much-needed attention by the researchers due to their low toxic nature. In recent years, chitosan has gained popularity as a potential biodegradable polymer that can be used as a component in drug delivery systems. In this study, we synthesized a chitosan derivative that is composed of both folic acid and zinc and may serve as a viable component of a drug delivery system. The results of Fourier Transform Infrared Spectroscopy (FTIR), solid-state 13C Nuclear Magnetic Resonance Spectroscopy (NMR) and UV-visible Spectroscopy demonstrated a substantial difference between chitosan and ZnS/Chitosan-Folic acid derivative. The results were also confirmed using Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM-EDS) techniques. The average particle size of the ZnS/Chitosan-Folic acid system was measured to be 463.67 ± 5.76 nm, showing that the product is within the nano-size range.

ABO-blood-group types and protection against severe, Plasmodium falciparum malaria

Although the ABO blood group of the human host has been reported to influence malarial infection, there have been few clinical observations on this effect. A hospital-based, comparative study was therefore performed to investigate the relationship between blood-group type and severe disease i nPlasmodium falciparum malaria. Overall, 243 cases of malaria (163 uncomplicated and 80 severe) and 65 patients with severe, non-malarial infections were studied. In terms of ABO-blood-group composition, the patients with severe malaria were significantly different from the patients with the uncomplicated disease (P<0.001) and also from a population control described previously (P<0.0001). The patients with uncomplicated malaria or severe but non-malarial disease were, however, similar to the population control. The cases of severe malaria were significantly less likely to be of blood group O (P=0.0003), and significantly more likely to be of group AB (P<0.0001), than the patients with nonsevere malaria. It appears that individuals who are of blood-group O are relatively resistant to the severe disease caused by P. falciparum infection.

TNFalpha*2 marks high risk of severe disease during Plasmodium falciparum malaria and other infections in Sri Lankans

We have investigated the association between alleles of the genes for tumour necrosis factor-alpha (TNF-alpha) and TNF-beta and severity of disease during malarial (Plasmodium falciparum) and other infections in the Sri Lankan population. Patients were categorized as having either (i) uncomplicated malaria, (ii) severe and complicated malaria, or (iii) severe and complicated infection in which a diagnosis of malaria had been excluded. For all the patients, as well as for a group of matched healthy controls, TNF-alpha and TNF-beta allelic types were identified using the polymerase chain reaction (PCR) and allele-specific oligonucleotide probes and restriction enzyme digestion. The odds in favour of carrying the TNFalpha*2 allele, mainly of the heterozygous genotype (TNFalpha*1,*2), were two to three times greater among individuals with severe disease, of either malarial or other infectious origin, relative to healthy controls or to those with uncomplicated malarial infections. No significant risk was associated with either of the alleles of TNF-beta.

Technical considerations for the use of independent collimators to achieve optimal photon field matching in radiotherapy

The dose uniformity across a junction between two abutting photon fields can be optimised by creating non-divergent field edges using independent collimators. Current linear accelerator specifications for the positional accuracy of such collimators are not rigorous enough to ensure that a clinically acceptable match is produced. Confirmation of the junction dose is required prior to clinical use and additional quality assurance is necessary to ensure that the strict requirement for positional accuracy is maintained.