Topics in Current Chemistry (2020) 378:15
1 3
properties and tubular shape. Silviana Fiorito et al. [185] reported the activation of
microglia using MWCNTs with highly electro-conductive properties, polarizing the
microglia cells into M1 state (pro-inflammatory) after 24 h of cell exposure and M2
state (anti-inflammatory) after 48 h of exposition. They detected this phenomenon
in vitro using primary rat microglial cells, suggesting that the electro-stimulation of
these CNTs could modulate microglial responses.
The use of carbon nanotubes as scaffolds for neurons has also been well studied,
as they are good platforms for protecting neuron damage in ischemia [186]. Jung
Lee et al. pretreated rats with amine-modified SWCNTs before an ischemic surgery,
finding less tissue damage and better motor function in the treated animals after the
insult. More recently, CNTs were reported as good scaffolds for different types of
neurons, like retinal neurons or sciatic nerve [187]. In this work, the authors studied retinal cell growth in vitro using MWCNTs as frame to these cells. They followed the procedure with rat and human retinal cells, finding an efficient growth for
both of them. Salehi et al. [188] developed a conduit produced from polylactic acid,
MWCNTs, and gelatin nanofibrils coated with the recombinant human erythropoietin-loaded chitosan nanoparticles. They loaded this conduit with Schwann cells and
implanted it in rats with sciatic nerve defect, finding improved recovery rate. Finally,
carbon nanotubes have also shown some neuroprotector properties. Xue et al. [189]
reported that C57BL/6J mice pretreated with aggregated SWCNTs significantly
inhibited self-administration of methamphetamine. The electrochemical assays indicated that nanotubes made the oxidation of extracellular dopamine in the striatum
easier, suggesting the potential use of aggregated SWCNTs for the treatment of
methamphetamine addiction.
4.3 Theranostic Applications
Theranostic compounds are nanoparticles integrating both diagnostic and therapeutic capabilities into a platform. CNTs have been intensively studied for theranostic
applications [163], as they can be easily coupled with different molecules/structures
achieving synergetic analytic and curative effects [190]. Basically, this approach
relies on the CNT functionalization with structures carrying abilities for detecting
and treating the disease, achieving at the same time cell targeting and delivering
of the drug under microenvironmental stimuli. Some examples have already been
presented in earlier. Mashal et al. [191] constructed tissue-mimicking materials and
found that SWCNTs could enhance dielectric contrast between tumoral and healthy
tissue for microwave detection and hyperthermia treatment in breast cancer. More
recently, Al Faraj et al. [192] described the preparation and the in vitro and in vivo
characterization of drug-conjugated SWCNTs as nanocarriers for breast cancer therapy. The authors aimed to target a stem cell subpopulation with a combination of
therapeutic drugs (paclitaxel and salinomycin) selectively delivered via biocompatible CD44 antibody-conjugated SWCNTs with a pH-responsive release. The therapy
was non-invasively monitored in tumor-bearing mice with MRI and bioluminescence imaging (BLI), and the results clearly showed enhanced therapeutic effect of
200
Reprinted from the journal
1 3
properties and tubular shape. Silviana Fiorito et al. [185] reported the activation of
microglia using MWCNTs with highly electro-conductive properties, polarizing the
microglia cells into M1 state (pro-inflammatory) after 24 h of cell exposure and M2
state (anti-inflammatory) after 48 h of exposition. They detected this phenomenon
in vitro using primary rat microglial cells, suggesting that the electro-stimulation of
these CNTs could modulate microglial responses.
The use of carbon nanotubes as scaffolds for neurons has also been well studied,
as they are good platforms for protecting neuron damage in ischemia [186]. Jung
Lee et al. pretreated rats with amine-modified SWCNTs before an ischemic surgery,
finding less tissue damage and better motor function in the treated animals after the
insult. More recently, CNTs were reported as good scaffolds for different types of
neurons, like retinal neurons or sciatic nerve [187]. In this work, the authors studied retinal cell growth in vitro using MWCNTs as frame to these cells. They followed the procedure with rat and human retinal cells, finding an efficient growth for
both of them. Salehi et al. [188] developed a conduit produced from polylactic acid,
MWCNTs, and gelatin nanofibrils coated with the recombinant human erythropoietin-loaded chitosan nanoparticles. They loaded this conduit with Schwann cells and
implanted it in rats with sciatic nerve defect, finding improved recovery rate. Finally,
carbon nanotubes have also shown some neuroprotector properties. Xue et al. [189]
reported that C57BL/6J mice pretreated with aggregated SWCNTs significantly
inhibited self-administration of methamphetamine. The electrochemical assays indicated that nanotubes made the oxidation of extracellular dopamine in the striatum
easier, suggesting the potential use of aggregated SWCNTs for the treatment of
methamphetamine addiction.
4.3 Theranostic Applications
Theranostic compounds are nanoparticles integrating both diagnostic and therapeutic capabilities into a platform. CNTs have been intensively studied for theranostic
applications [163], as they can be easily coupled with different molecules/structures
achieving synergetic analytic and curative effects [190]. Basically, this approach
relies on the CNT functionalization with structures carrying abilities for detecting
and treating the disease, achieving at the same time cell targeting and delivering
of the drug under microenvironmental stimuli. Some examples have already been
presented in earlier. Mashal et al. [191] constructed tissue-mimicking materials and
found that SWCNTs could enhance dielectric contrast between tumoral and healthy
tissue for microwave detection and hyperthermia treatment in breast cancer. More
recently, Al Faraj et al. [192] described the preparation and the in vitro and in vivo
characterization of drug-conjugated SWCNTs as nanocarriers for breast cancer therapy. The authors aimed to target a stem cell subpopulation with a combination of
therapeutic drugs (paclitaxel and salinomycin) selectively delivered via biocompatible CD44 antibody-conjugated SWCNTs with a pH-responsive release. The therapy
was non-invasively monitored in tumor-bearing mice with MRI and bioluminescence imaging (BLI), and the results clearly showed enhanced therapeutic effect of
200
Reprinted from the journal