Chiral Control of Carbon Dots via Surface Modification for Tuning the Enzymatic Activity of Glucose Oxidase

Abstract

Chiral carbon dots (CDs) integrated the advantages of achiral CDs and the unique chiral property, which expand the prospect of the biological applications of CDs. However, the structure control and the origin of chirality for chiral CDs remain unclear. Herein, chiral CDs were obtained by thermal polymerization of chiral amino acids and citric acid, and their handedness of chirality could be controlled by adjusting the reaction temperature, which leads to different kinds of surface modifications. With aliphatic amino acids as a chiral source, all of the CDs that reacted at different temperatures (90–200 °C) have the same handedness of the chiral source. But with aromatic amino acids as a chiral source, CDs with maintained or inversed handedness compared with the chiral source could be obtained by adjusting the reaction temperature. Below a temperature of 120 °C, the chiral source was modified with CDs by esterification and transferred the handedness of chirality; at high temperatures (above 150 °C), which mainly connected by amidation accompanying with the formation of rigid structure generated by the π conjugation between the aromatic nucleus of chiral source and the carbon core of CDs, caused the inversing of the chiral signal. Further, we investigated the chiral effects of CDs on the glucose oxidase activity for a highly sensitive electrochemical biosensor.

Influence of the chirality of carbon nanodots on their interaction with proteins and cells

“…In fact, reports exist in which adsorption of proteins, the so-called protein corona 16 was found to depend on the chirality of the NPs 17 – 23 . Previous studies on carbon nanodots (CNDs) have focused on studying the effect of opposite chiral carbon dots in their biocompatibility and toxicity to liver HepG2 cells 9 , stereoselective interaction with the prion protein 24 , tuning enzymatic activity 25 – 27 , interaction with the Golgi apparatus 28 , studying their effect on plant growth 29 , as well as establishing methods for detecting the interaction between achiral carbon dots and proteins 30 .…”

Plasmon-Enhanced Antibacterial Activity of Chiral Gold Nanoparticles and In Vivo Therapeutic Effect

“…As for the antibacterial mechanism of d -Au NPs, we hypothesis that d -cys-modified Au NPs may specifically bind to the proteins on the cell membrane of bacteria and result in the destruction of cell membrane integrity by changing the structure of proteins [ 56 ], which was consistent with the TEM images ( Figure 3 A). Chiral nanomaterials-induced structure changes of proteins have been reported in previous works [ 57 , 58 ]. On the other hand, a portion of d -Au NPs may enter the bacteria by endocytosis, affecting the physiological activity of bacteria through interactions with proteins and DNA, resulting in cell death.…”

Carbon Nanomaterials (CNMs) and Enzymes: From Nanozymes to CNM-Enzyme Conjugates and Biodegradation

“…Therefore, its inhibition could find several useful applications [ 350 ]. Furthermore, CNDs were found to tune glucose oxidase activity, depending on their functionalization type [ 224 ], and inhibit maltase, an effect that was envisaged as an innovative means to control physiological glucose levels [ 230 ].…”

“…As can be seen from Table 1 , the vast majority of CNM-enzyme conjugates have been studied for biosensing applications. The most popular target molecule is glucose for biometric health monitoring ( Table 2 ) [ 224 , 227 , 228 , 237 , 249 , 269 , 271 , 273 ]. However, biosensors have been developed to detect many other bioactive compounds too, such as cholesterol [ 312 , 370 , 371 ] and triglycerides [ 282 ], lactose [ 220 ] and lactate [ 225 , 280 ], neurotransmitters [ 234 , 240 , 246 , 278 , 279 , 372 ] and hormones [ 239 ], various disease biomarkers [ 244 , 257 , 261 ], microRNAs [ 223 ], drugs [ 218 , 287 ], pathogens [ 219 ] and toxins [ 221 ], xanthine [ 262 ] and caffeic acid [ 373 ], p -coumaric acid [ 232 ], ferulic acid [ 233 ], trace metals [ 274 ], and oxygen [ 268 ].…”