In an article recently published in the journal Applied Surface Science, the researchers synthesized green fluorescent carbon dots (G-CDs) from 3,5-diaminobenzoic acid and citric acid. The as-prepared G-CDs were used to target the nucleolus and to carry exogenous DNA molecules into the nucleolus. In addition, the carbon dots (CDs) were used to monitor the levels of nitrite ions (NO2–) and pH in biological cells.
Role of Nucleolus, NO2– and pH in Living Cells
CDs are carbon nanomaterials considered quasispherical particles with a size of fewer than 10 nanometers. Due to their advantages, including outstanding photostability, superior photoluminescence, excellent biocompatibility low toxicity, and easy functionalization, CDs are extensively applied in biological sensing, cell imaging, gene delivery, catalysis, and fingerprints detection.
The nucleolus is located inside the nucleus and it is the site for processing ribosomal RNA (rRNA) transcripts, ribosomal DNA transcription by RNA polymerase I, and ribosome assembly. Monitoring the state of the nucleolus is critical for detecting malignant lesions and developing accurate treatment.
Although CDs were recently applied as fluorescent (FL) labeling reagents for nucleolus staining, their research application as nucleolus-targeted probes is practically unexplored.
Many human diseases are caused by genetic changes inside the nucleolus. Thus, transmitting normal genes with therapeutic efficacy into the nucleolus can exert a therapeutic role or correct gene defects. However, the internalization of naked genetic materials by target cells may be hampered due to phagocyte uptake, susceptibility to serum nuclease, or rapid renal clearance. To this end, various vectors were developed to introduce the gene into the nucleolus. However, these vectors have limitations like high toxicity and low transfection efficiency.
NO2– is used as a preservative in the food industry. Although a moderate amount of NO2– is beneficial to human health, excess presence could convert hemoglobin into methemoglobin in human blood, which may cause hypoxia and interact with secondary amines and amides present in the stomach to produce nitrosamine and may induce cancer and hypertension. Thus, detection of NO2– is critical for disease diagnosis. Similarly, pH plays a vital role in physiological processes, and irregular pH changes lead to various diseases. Measuring intracellular pH is also crucial for disease diagnosis.
G-CDs for Nucleolus Targeting, Gene Delivery, and Biosensing of NO2– and pH
In the present study, the researchers synthesized G-CDs from citric acid and 3,5-diaminobenzoic acid via a single-step hydrothermal method. As-prepared G-CDs showed excellent biocompatibility and low toxicity. The G-CDs were applied to the target nucleolus based on G-CD’s DNA-sensitive properties to carry the exogenous DNA into the nucleolus. Moreover, the G-CDs were used to monitor NO2– and pH in a biological cell.
Research Findings
Transmission electron microscope (TEM) images demonstrated G-CDs’ quasi-spherical structure with favorable dispersion and size distribution in the scope of 1-5 nanometers with an average size of 2.16 ± 0.52 nanometers. Atomic force microscopy revealed that G-CDs’ height range was between 5.2 and 5.1 nanometers.
Fourier transform infrared (FTIR) spectrum and X-ray diffraction patterns inferred the composition and functional groups. G-CD’s XRD pattern showed three characteristic peaks at 281.9, 396.9, and 528.8 electronvolts corresponding to C1s, N1s, and O1s, respectively.
The C1s spectrum illustrated four peaks corroborating the existence of the following bonds, carbon-carbon double (C=C, 284.8 electronvolts), carbon-nitrogen (C-N, 286 electronvolts), acetyl (O=C–C, 287.8 electronvolts) and carbonyl (C=O, 288.9 electronvolts). N1s spectrum decomposed into three peaks corresponding to carbon-nitrogen-carbon (C-N-C, 398.8 electronvolts) and nitrogen-hydrogen (N-H, 400.1 electronvolts). O1s spectrum also decomposed into three peaks of C=O (531.8 electronvolts) and carbon-hydroxyl (C-OH, 533.2 electronvolts), and ether (C-O-C, 533.9 electronvolts)
FTIR spectrum showed absorption bands for N–H and C–H at 2927.3 and 2579.3-centimeter inverse, respectively. The peak at 1690.9-centimeter inverse corroborated the existence of the C=O functional group, those at 1593.9 and 1464.4-centimeter inverse COO– group. Moreover, the peaks at 1394.7, 1334.8, 1210.5, and 1121.1-centimeter inverse correspond to C–H bending vibration, C-N stretching vibrations, O-H and C–O bond, respectively.
G-CD’s complex efficiency for DNA was investigated through an agarose gel electrophoresis assay by observing the movement of DNA. The results showed that free DNA had easy migration to the opposite end, while with the increasing weight ratio of G-CD to DNA, DNA binding with G-CD was gradually blocked, and complete blockage occurred when the ratio reached 50:1. Complete blockage in DNA migration confirms the effective loading of DNA in G-CDs.
Conclusion
To conclude, the researchers used 3,5-diaminobenzoic acid and citric acid as precursors to develop G-CDs via a single-step hydrothermal reaction. The as-prepared G-CDs served the purpose of staining nucleolus, carrying exogenous DNA into nucleolus, and visually monitoring pH and NO2– variations in living cells. Additionally, the team anticipated that the proposed G-CDs were biocompatible gene carriers with low toxicity. Thus, these CDs have good prospects in gene therapy that targets nucleolus.
News
Could a Nasal Spray Stop Alzheimer’s Before Memory Loss Begins?
Protecting memory from Alzheimer’s may one day involve a nasal spray, with encouraging results in animals and evidence that its particles also protect human neurons grown in the lab. Alzheimer’s disease damages the connections [...]
A sceptical guide to AI agents in drug discovery
In conversation with Dr Eric Ma, Senior Principal Data Scientist at Moderna, Dr Raminderpal Singh examines what AI agents are actually good for, where the lock-in hides and why expertise has become more valuable [...]
Study identifies new targets for antiviral drugs against coronaviruses
A study led by researchers at the University of California San Diego School of Medicine and University of California, Riverside (UCR) School of Medicine has identified new targets for antiviral drugs against coronaviruses, including [...]
“Nearly Everybody Had Given Up” – Scientists Finally Solve a 60-Year Chemistry Mystery
After more than six decades of failed attempts, chemists have achieved a breakthrough involving a class of molecules long considered too unstable to isolate. Chemists have succeeded in isolating a group of molecules that [...]
Depression Symptoms Improved in Just 48 Hours After a Single Psychedelic Dose
A single dose of psilocybin produced rapid antidepressant effects in a small Swedish clinical trial, with improvements lasting for weeks. A single dose of psilocybin, the psychedelic compound found in magic mushrooms, produced rapid [...]
GHCE Concept
From the preface of the book Global Health Care Equivalency in the Age of Nanotechnology, Nanomedicine and Artificial Intelligence, Edited by Frank Boehm: Since the publication of my first book (Nanomedical Device and Systems [...]
Human Bodies Are Producing Two Billion Tons of CO2 a Year
A new study reveals that the amount of carbon dioxide produced by human metabolism has increased dramatically over three decades. The carbon dioxide produced by human bodies as they convert food into energy increased [...]
A Hidden DNA Mechanism Could Explain How 20% of Human Cancers Develop
Researchers have identified an unexpected molecular vulnerability in cancers carrying BAF mutations. Mutations found in roughly 20% of human cancers may promote tumor growth by changing how DNA is organized inside cells. Researchers have [...]
Ebola kills over 5,300 in fastest-growing outbreak on record
Africa’s latest Ebola outbreak has killed nearly 5,400 people, the vast majority of them in the Democratic Republic of Congo (DRC), according to the continent’s top health agency. Africa Centres for Disease Control and [...]
China makes early progress in using sound waves to stimulate damaged brains
Chinese researchers are testing whether focused ultrasound can help restore consciousness in patients with severe brain injuries, adding to a growing international effort to use sound waves to stimulate deep brain structures without surgery. [...]
Micro-drones fly through the body thanks to ultrasound
At the EPFL, micro-drones have been developed that can be moved without a motor or battery.No motors, no batteries, no electronics on board, just small cavities that convert sound waves into thrust: this is [...]
A Single Enzyme Could Hold the Key to Treating a Devastating Brain Disorder
Blocking an enzyme’s production restored brain growth and healthy behaviors in mice engineered to develop Angelman syndrome, pointing to a possible treatment target. Children with Angelman syndrome begin to show difficulties with thinking and [...]
Scientists Develop a Clever New Way To Kill Cancer Cells From the Inside
Scientists have developed an experimental strategy that exploits a chemical byproduct of cancer cells to produce anticancer drugs directly inside them. Scientists in Japan have developed an experimental method that uses a chemical produced [...]
Our books are available worldwide!
Online Sellers other than Amazon, Routledge, and IOPP Indigo Global Health Care Equivalency in the Age of Nanotechnology, Nanomedicine and Artifcial Intelligence Global Health Care Equivalency In The Age Of Nanotechnology, Nanomedicine And Artificial [...]
After only a short training, people in a coma managed to send targeted signals
Researchers have succeeded in communicating with brain-injured patients who are unconscious. They see enormous potential in this for future treatments. Patients who lie motionless in bed after a severe brain injury and do not [...]
MIT Scientists Reprogram Immune Cells Inside the Body To Destroy Cancer
Natural killer cells reprogrammed inside mice eliminated lymphoma tumors and helped damaged livers heal, though whether this approach could help people with cancer or autoimmune disease remains unknown. To make a cancer treatment from [...]
