Graphene is a two-dimensional carbon nanomaterial with hexagonal honeycomb lattice composed of carbon atoms with sp2 hybrid orbitals.
Graphene has excellent optical, electrical, and mechanical properties, and has important application prospects in materials science, micro / nano processing, energy, biomedicine, and drug delivery. It is considered to be a revolutionary material in the future. Physicists Andre Gem and Konstantin Novoselov of the University of Manchester, UK, successfully separated graphene from graphite by micromechanical exfoliation, and thus won the 2010 Nobel Prize in Physics.
Application of Graphene / Graphene Oxide (G / GO) in Biomedical Field
Biosensor and bioimaging
Superparamagnetically functionalized G-Fe3O4 @ Au is used for magnetron solid state electroluminescent biosensing. The conjugate was found to have long-term stability, high emission intensity, high reproducibility, excellent electron transfer and superparamagnetism And it has high sensitivity for Hela cell imaging. Co3O4-G modified carbon electrode can selectively detect atropine in biological fluids. Non-covalently functionalized monolayer G can be used as a sensitive enhanced surface plasmon resonance immunosensor. G-Cu conjugates are used as surface-enhanced Raman scattering (SERS) substrates to detect adenosine by chemical vapor deposition in methanesulfonic acid and hydrogen. The GO-CD mixture can be used for the selective labeling of cytoplasm. GO will serve as a substrate for fixed quaternary ammonium-modified carbohydrates, so that it can preferentially label the cytoplasm, and the carbon dots will enter the nucleus as fluorescent labels.
Biological therapy
The small size GO flakes show high NIR light absorption and biocompatibility, and can be used as a potential material for photothermal therapy. Transdermal nano-GO-hyaluronic acid (NGO-HA) conjugates can be used to treat melanoma under near-infrared laser irradiation. Atom transfer radical polymerization (ATRP) was introduced to contain the starting point of disulfide bonds on the surface of GO, and then GO was modified by ATRP and (2-diamino) ethyl methacrylate (DMAEMA) to synthesize a series of organic- Inorganic complexes (abbreviated as SS-GPDs), have good gene transfer effect. SS-GPD materials can attach and absorb aromatic water-insoluble drugs, such as CPT. Due to the conjugate structure of the GO substrate plane, it can effectively kill cancer cells.
Non-covalently functionalized G / GO nanomaterials can be used as drug carriers. The non-covalent hydrophobicity of π-π conjugation with the drug's aromatic ring produces a drug-loading effect. And glutathione can destroy the π-π conjugated and non-covalent hydrophobic interaction of GO aromatic ring and cause drug release. The complex formed by rGO with branched polyethyleneimine (BPEI) and polyethylene glycol (PEG) through π-π conjugate (PEG-BPEI-rGO) is a good carrier for doxorubicin (DOX). After PEG-BPEI-rGO enters the cell through endocytosis, the conjugated system is destroyed by the photothermal effect, it can escape from the cell, and the drug is released into the cytoplasm. By using poly (L-lactide) (PLA) and polyethylene glycol (PEG) grafted GQDs to synthesize multifunctional conjugates as specific gene targeting agents, it has good physiological stability and biocompatibility And long-lasting photoluminescence properties. Targeted miRNA-21 is adsorbed on the surface of GQDs to achieve targeted gene therapy for cancer cells, which shows a significant inhibitory effect on the growth of cancer cells.