Recent advances in biomedical applications of carbon and graphene quantum dots: A review.

The carbon-based nanostructures have led to the development of theranostic nanoplatforms for simultaneous diagnosis and therapy due to their effective cell membrane-penetration ability, low degree of cytotoxicity, excellent pore volume, substantial chemical stability, and reactive surface. In the last few years, extensive efforts were made to design multifunctional nanoplatform strategies based on carbon nanostructures, involving multimodal imaging, controlled drug release capabilities, sensing in vitro, efficient drug loading capacity, and therapy. Carbon and graphene quantum dots (CQDs and GQDs) were the recent entrants, contingently being assessed for drug delivery and bioimaging. With the advancements, these quantum dots have ignited remarkable research interest and are now widely evaluated for diagnosis, bioimaging, sensing, and drug delivery applications. The last decade has witnessed their remarkable electrical, optical, and biocompatible properties since their inception. It is presumed that both of them have high potential as drug carriers and would serve as the next generation of approaches to address numerous unresolved therapeutic challenges. This review examined the recent advances of CQD and GQD based drug delivery applications, challenges, and future perspectives to pave the way for further studies in the future.

Relation of soya bean meal level to the concentration of plasma free amino acids and body growth in white rats.

Amino acid (AA) levels in plasma and body growth were determined in rats (n20) fed diets with different soya bean meal levels. Free AA in plasma was determined by reversed-phase high-pressure liquid chromatography. We have used four levels of protein diets like 8%, 15%, 23% and 35% in this trial. Rats which were fed the low-protein (8%) diet with low percentage of soya bean meal were found to be growth-retarded. The body weight gain of high protein group (35%) was lower than that of the 23% groups. In the rats fed with the low-soya bean meal diet, some nonessential AA (NEAA) in plasma like asparagine, aspartic acid, cysteine, glutamic acid and serine increased, whereas the essential AA (EAA), with the exception of arginine, methionine and valine decreased. Here, plasma EAA-to-NEAA ratios were not correlated to growth and experimental diet. We hypothesize that AA metabolism is associated to changes in growth in rats on different protein intake. This study has showed the sensitivity of body mass gain, feed intake, feed conversion rate of rats to four levels of protein in the diet under controlled experimental conditions.

Carbon nanocubes and nanobricks from pyrolysis of rice.

Carbon nanocubes and nanobricks were synthesized by pyrolyzing rice powder at 600 degrees C under nitrogen atmosphere. Purification with concentrated nitric acid introduced approximately 0.1 mol/g of carboxylic acid groups as found by acid-base titrimetric analysis. XRD pattern showed the 0.15 mol/g basic graphitic structure of these nano carbon materials. Their SEM and TEM images revealed cube or brick shaped nano crystals. These nanocrystals are further characterized by FT-IR, Raman, and EDAX analysis. High density wrapping of carboxylated acid groups introduces surface passivation of these nano carbon cubes and nano carbon bricks exhibiting photoluminescence. Solid state electronic spectrum showed several bands in the ultraviolet and visible region and excitation at 336 and 474 nm generates photoluminescence respectively in the ultraviolet and visible region.

Synthesis of carbon nanosheet from barley and its use as non-enzymatic glucose biosensor.

In this work, carbon nanosheet (CNS) based electrode was designed for electrochemical biosensing of glucose. CNS has been obtained by the pyrolysis of barley at 600-750 °C in a muffle furnace; it was then purified and functionalized. The CNS has been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopic techniques. The electrochemical activity of CNS-based electrode was investigated by linear sweep voltammetry (LSV) and square wave voltammetry (SWV), for the oxidation of glucose in 0.001 M H2SO4 (pH 6.0). The linear range of the sensor was found to be 10-4-10-6 M (1-100 µM) within the response time of 4 s. Interestingly, its sensitivity reached as high as ~26.002±0.01 µA/µM cm2. Electrochemical experiments revealed that the proposed electrode offered an excellent electrochemical activity towards the oxidation of glucose and could be applied for the construction of non-enzymatic glucose biosensors.