Mass Spectrometry-Based Analyses of Carbon Nanodots: Structural Elucidation.

Carbon nanodots (CNDs) are nanomaterials with ubiquitous applications in health for diagnosis and treatments. The key to enhancing the applications of carbon nanodots in various fields lies on how deep its structure is understood. Here, we review the mass spectroscopy (MS) techniques employed for carbon nanodot analysis. We aimed to revive the use of MS to support the structural elucidation of carbon nanodots. General techniques used in nanomaterials characterization include laser desorption/ionization (LDI), matrix-assisted LDI (MALDI), inductively coupled plasma (ICP), and electrospray ionization (ESI) MS. For CNDs characterization, LDI-MS, MALDI-MS, and ESI-MS were employed. The techniques required further instrumentations of time-of-flight (TOF), for MALDI, and TOF, quadrupole (Q), and tandem (MS/MS) for ESI. LDI-MS could be applied to prove the surface and core structural composition of carbon nanodots. Meanwhile, MALDI-MS was used to elucidate the surface structures of CNDs. Finally, ESI-MS could provide significant insight into the carbon nanodots' structural composition and bonding patterns. In summary, MS could be combined with other techniques to unambiguously elucidate the structure of carbon nanodots.

A Perspective on Using Organic Molecules Composing Carbon Dots for Cancer Treatment.

Fluorescent Carbon dots (CDs) derived from biologically active sources have shown enhanced activities compared to their precursors. With their prominent potentiality, these small-sized (<10nm) nanomaterials could be easily synthesized from organic sources either by bottom-up or green approach. Their sources could influence the functional groups present on the CDs surfaces. A crude source of organic molecules has been used to develop fluorescent CDs. In addition, pure organic molecules were also valuable in developing practical CDs. Physiologically responsive interaction of CDs with various cellular receptors is possible due to the robust functionalization on their surface. In this review, we studied various literatures from the past ten years that reported the potential application of carbon dots as alternatives in cancer chemotherapy. The selective cytotoxic nature of some of the CDs towards cancer cell lines suggests the role of surface functional groups towards selective interaction, which results in over-expressed proteins characteristic of cancer cell lines. It could be inferred that cheaply sourced CDs could selectively bind to overexpressed proteins in cancer cells with the ultimate effect of cell death induced by apoptosis. In most cases, CDs-induced apoptosis directly or indirectly follows the mitochondrial pathway. Therefore, these nanosized CDs could serve as alternatives to the current kinds of cancer treatments that are expensive and have numerous side effects.

An intestinal Candida albicans model for monomicrobial and polymicrobial biofilms and effects of hydrolases and the Bgl2 ligand.

Background and Aim: Candida albicans is the most prevalent human fungal pathogen. In biofilms, C. albicans becomes more resistant to antifungal agents because of the production of an extracellular matrix (ECM) that protects the yeast cells. This study aimed to determine the effects of hydrolase enzymes and the Bgl2 ligand on monomicrobial and polymicrobial biofilms. Materials and Methods: Biofilm induction in rats was carried out using streptomycin (25 mg/kg) and gentamicin (7.5 mg/kg) administered orally once per day for 5 days. Rats were injected subcutaneously with cortisone acetate (225 mg/kg) as an immunosuppressant on day 5. In addition, rats were orally administered C. albicans for the single microbial model and a combination of C. albicans with Escherichia coli for the polymicrobial model. Following the biofilm production, the groups were treated with glucosamine (8.57 mg/kg body weight) and Achatina fulica hydrolases (1.5 mL) orally for 2 weeks. The reduction of the biofilm was measured using confocal laser scanning microscopy (CLSM). Data were analyzed using a t-test, with a significance value of 95%. Results: CLSM images revealed a strong association between C. albicans and E. coli in the polymicrobial biofilm. On the contrary, the combination treatment using glucosamine and A. fulica hydrolases reduced the ECM of the single microbial biofilm (53.58%). However, treatment effectiveness against the matrix (19.17%) was reduced in the polymicrobial model. Conclusion: There is a strong association between C. albicans and E. coli in the formation of polymicrobial biofilms. The combination of glucosamine and the A. fulica enzyme can reduce the single microbial biofilm ECM; however, it is ineffective in the polymicrobial model.

Naproxen release behaviour from graphene oxide/cellulose acetate composite nanofibers.

The present study investigated the effect of graphene oxide in cellulose acetate-based composite nanofibers on the transdermal delivery of naproxen. The composite nanofibers were successfully produced via the electrospinning process by directly mixing cellulose acetate, graphene oxide, and naproxen solution with varied compositions. The formation of the nanofibers was confirmed by electron microscopy and other characterization techniques to prove the existence of graphene oxide and naproxen itself. Surprisingly, graphene oxide encourages the production of nanofibers with smaller average diameter, higher conductivity, higher mechanical strength, and higher naproxen release from the cellulose acetate nanofibers. Once combined with naproxen, the composite nanofiber exhibited antibacterial activity with an inhibitory zone of 9.15 mm. The cytotoxicity evaluation also showed that the addition of naproxen increased the death of HeLa cells with a CC50 of up to 29.33 µg mL-1. The kinetic model of naproxen release follows the Korsmeyer-Peppas and Higuchi models with acceleration at neutral pH. These results are promising for further applications for wound healing purposes.

Addition of binahong (Anredera cordifolia) leaf powder to diets to produce eggs with low cholesterol.

AIM: The aim of this study was to evaluate the effect of the addition of binahong leaf powder to quail rations on the production and quality of eggs. MATERIALS AND METHODS: The study involved the use of two hundred 7-week-old quails housed evenly in 20 wire cages with a body weight of 123.77±0.72 g. The quails were treated as follows: Ration without binahong leaf powder (T0), addition 2% of binahong leaf powder (T1), addition 4% of binahong leaf powder (T2), and addition 6% of binahong leaf powder (T3). The study used a completely randomized design. The parameters measured were the production, weight, and characteristics of the eggs, as well as the cholesterol, triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and egg protein content in the yolk. RESULTS: The addition of 2-6% binahong powder did not significantly affect egg production, egg characteristics, or egg protein content, but significantly (p<0.05) affected the cholesterol, triglyceride, HDL, and LDL contents in yolk. The cholesterol, triglyceride, and LDL contents decreased significantly in T1, whereas HDL increased significantly in T2 and T3. CONCLUSION: The addition of 2% binahong was enough to obtain healthy quail eggs with low levels of cholesterol, triglyceride, and LDL.

A Novel 1,3-Β-Glucanase Gene from the Metagenomic Expression Library of Achatina Fulica's Digestive Gland.

1,3-ß-glucanase enzyme has been proved as antibiofilm by hydrolyzing the main component of extracellular matrix of C. albicans polymicrobial biofilm, to prevent resistancy during the use of antibiotics. The aim of this study is to construct a metagenomic expression library from Achatina fulica's digestive gland and to screen for a novel 1,3-ß-glucanase genes by using its specific substrate of laminarin. A cDNA expression library was constructed using the λTriplEx2 vector in the E. coli strain XL1-Blue. Cre-recombinase circularization was used to convert λTriplEx2 to pTriplEx2 in the E. coli strain BM 25.8;then IPTG induction was used to express 1,3-ß-glucanase. High-efficiency cDNA library of A. fulica's digestive gland was constructed, from where we obtained seventeen halo positive plaques, among them is a novel 1,3-ß-glucanase gene designated MkafGlu1. Its nucleotide sequence has similarities to the endo-1,3-ß-glucanase from Gossypium hirsutum, as well as the ß-glucanases from Paenibacillus mucilaginosus, Verticillium alfalfa, and Cryptopygus antarcticus of 45%, 40%, 38% and 37%, respectively. An open reading frame of 717 bp encoded a protein of 239 amino acids. A novel 1,3-ß-glucanase gene called MkafGlu1 was successfully expressed in E.coli BM 25.8 with activity of 1.07 U mL-1.