Topics in Current Chemistry (2020) 378:40
1 3
Zheng et al. [234] synthetized a tumor-specific peptide-decorated liposome containing payloads of IONPs and an anti-cancer drug in their inner core and lipid bilayer,
respectively. Like the protocol described above, the combination in a single pot reaction
of egg phosphatidylcholine, cholesterol, paclitaxel (PTX), different 1,2-distearoyl-snglycero-3-phosphoethanolamine (DSPE) phospholipids, such as DSPE-PEG and cell
penentrating peptide-modified DSPE-PEG, and hydrophilic SPION, generated a theranostic liposome. The results confirmed the effectiveness for tumor targeting and antitumor activity through MRI in vivo experiments.
3.1.4 Nanogels
Nanogels (NGs) are nanosized water-soluble particles formed by crosslinked polymer
networks with loading capacity of therapeutics. Stimuli-responsive NGs are a class of
smart particles that respond to external physical changes, such as pH, temperature or
redox agents [235, 236]. This behavior allows the controlled-release of payloads from
NGs, minimizing possible side effects and avoiding the use of high doses. NGs can also
be loaded with diagnostic agents, such as magnetic NPs, enabling their visualization
and follow-up by MRI. These characteristics, together with the ease of uptake by cancer cells and tumor tissues due to their softness and fluidity, make NG-based nanosystems a high potential theranostic material [237, 238].
Qian et al. [239] prepared a hybrid NG system based on a thermo-responsive copolymer [N-isopropylacrylamide, methacrylic acid and poly (ethylene glycol) methacrylate] that stabilizes hydrophobic IONPs and 10-hydroxy camptothecin (HCPT) in
its inner compartment. The obtained IONP/HCPT-NG generated an increase in reactive
oxygen species (ROS), allowed the enrichment of NG at the tumor site by applying an
external magnetic field, and offered the possibility of being used as nanocarrier for photothermal therapy due to its absorption in the near infrared (NIR) range. In vivo results
demonstrated that the combination of PTT and chemotherapy with external magnetic
fields on IONP/HCPT-NGs, reduced the growth of primary tumors and prevented
metastasis [239].
Alginate (AG) is a natural polysaccharide that has been gaining attraction in recent
years for the synthesis of polymeric nanomaterials with biomedical applications thanks
to its biocompatibility, biodegradability and ease of gelation [240]. For instance, Hao
et al. [241] designed alginate NGs loaded with IONPs and bone mesenchymal stem
cells (BMSCs) for enhanced tumour MR imaging (Fig. 5). The potential advantage of
using BMSCs as tumor delivery vehicles is that they are not tumorigenic and minimally immunogenic. In this way, polyethilenimine (PEI)-functionalized IONPs were
crosslinked to AG NGs previously synthesized by a double emulsion method. The
resulting AG/PEI-NP NGs were taken up by BMSCs without affecting cell characteristics. BSMC-AG/PEI-NP NGs were then used successfully for the in vivo diagnosis of
different tumor models [241].
66
Reprinted from the journal
1 3
Zheng et al. [234] synthetized a tumor-specific peptide-decorated liposome containing payloads of IONPs and an anti-cancer drug in their inner core and lipid bilayer,
respectively. Like the protocol described above, the combination in a single pot reaction
of egg phosphatidylcholine, cholesterol, paclitaxel (PTX), different 1,2-distearoyl-snglycero-3-phosphoethanolamine (DSPE) phospholipids, such as DSPE-PEG and cell
penentrating peptide-modified DSPE-PEG, and hydrophilic SPION, generated a theranostic liposome. The results confirmed the effectiveness for tumor targeting and antitumor activity through MRI in vivo experiments.
3.1.4 Nanogels
Nanogels (NGs) are nanosized water-soluble particles formed by crosslinked polymer
networks with loading capacity of therapeutics. Stimuli-responsive NGs are a class of
smart particles that respond to external physical changes, such as pH, temperature or
redox agents [235, 236]. This behavior allows the controlled-release of payloads from
NGs, minimizing possible side effects and avoiding the use of high doses. NGs can also
be loaded with diagnostic agents, such as magnetic NPs, enabling their visualization
and follow-up by MRI. These characteristics, together with the ease of uptake by cancer cells and tumor tissues due to their softness and fluidity, make NG-based nanosystems a high potential theranostic material [237, 238].
Qian et al. [239] prepared a hybrid NG system based on a thermo-responsive copolymer [N-isopropylacrylamide, methacrylic acid and poly (ethylene glycol) methacrylate] that stabilizes hydrophobic IONPs and 10-hydroxy camptothecin (HCPT) in
its inner compartment. The obtained IONP/HCPT-NG generated an increase in reactive
oxygen species (ROS), allowed the enrichment of NG at the tumor site by applying an
external magnetic field, and offered the possibility of being used as nanocarrier for photothermal therapy due to its absorption in the near infrared (NIR) range. In vivo results
demonstrated that the combination of PTT and chemotherapy with external magnetic
fields on IONP/HCPT-NGs, reduced the growth of primary tumors and prevented
metastasis [239].
Alginate (AG) is a natural polysaccharide that has been gaining attraction in recent
years for the synthesis of polymeric nanomaterials with biomedical applications thanks
to its biocompatibility, biodegradability and ease of gelation [240]. For instance, Hao
et al. [241] designed alginate NGs loaded with IONPs and bone mesenchymal stem
cells (BMSCs) for enhanced tumour MR imaging (Fig. 5). The potential advantage of
using BMSCs as tumor delivery vehicles is that they are not tumorigenic and minimally immunogenic. In this way, polyethilenimine (PEI)-functionalized IONPs were
crosslinked to AG NGs previously synthesized by a double emulsion method. The
resulting AG/PEI-NP NGs were taken up by BMSCs without affecting cell characteristics. BSMC-AG/PEI-NP NGs were then used successfully for the in vivo diagnosis of
different tumor models [241].
66
Reprinted from the journal