Smart Nanomaterials for Biomedical Applications-A Review

Abstract

Recent advances in nanotechnology have forced the obtaining of new materials with multiple functionalities. Due to their reduced dimensions, nanomaterials exhibit outstanding physio-chemical functionalities: increased absorption and reactivity, higher surface area, molar extinction coefficients, tunable plasmonic properties, quantum effects, and magnetic and photo properties. However, in the biomedical field, it is still difficult to use tools made of nanomaterials for better therapeutics due to their limitations (including non-biocompatible, poor photostabilities, low targeting capacity, rapid renal clearance, side effects on other organs, insufficient cellular uptake, and small blood retention), so other types with controlled abilities must be developed, called "smart" nanomaterials. In this context, the modern scientific community developed a kind of nanomaterial which undergoes large reversible changes in its physical, chemical, or biological properties as a consequence of small environmental variations. This systematic mini-review is intended to provide an overview of the newest research on nanosized materials responding to various stimuli, including their up-to-date application in the biomedical field.

Keywords: biomedical applications; smart nanomaterials; stimuli-responsive polymers.

Figure 4

(a) Examples of photoisomerizable groups for reversible light-responsive nanomaterials. Reproduced from [65], with permission from © The Royal Society of Chemistry 2017. (b) Synthesis of PNc and UV light drug release. (c) Synthesis and photoisomerization process of PNSC amphiphilic copolymer. Reproduced from [70], with permission from © 2020 Mena-Giraldo, Perez-Buitrago, Londono-Berrío, Ortiz-Trujillo, Hoyos-Palacio, and Orozco under CC BY 4.0.

Figure 1

Classification and biomedical applications of smart nanomaterials as a function of their nanostructure.

Figure 2

Zwitterionic thermosensitive PNS nanogels. (a) Schematic synthesis of PNS nanogels. (b) Temperature dependence of hydrodynamic diameters and (c) temperature dependence of PNS transmittance. (d) TEM image. (e) Photos of the sol–gel phase transition. (f) Rheology of the sol–gel phase transition. (g) In vivo antitumor effect: the corresponding photographs of the peeled tumors after intratumoral injection for 14 days. Reproduced from [29], with permission from © The Royal Society of Chemistry 2020.

Figure 3

The hydrogel-based electroresponsive microfluidic actuator platform: (a) Illustration of the components of the electroresponsive microfluidic actuator platform. (b) Photo of microfluidic system, scale is 1 cm. (c) Proposed synthesis of peptide-conjugated gold nanorods. SEM images of (d) silver nanowires, (e) collagen I gels, and (f) electrosensitive hydrogels. (g) Elemental analysis of the electrosensitive hydrogel, scale is 1 µm. (h) Fluorescent images of “on/off” electrical stimuli influence on the fluorescein isothiocyanate–dextran propagation in the platform, scale is 500 µm. Reproduced from [57], with permission from © The Royal Society of Chemistry 2020.

Figure 5

Neuronal regeneration in a magnetic-responsive 3D hydrogel system. (a) Schematic presentation of magnetic-driven neuronal regeneration. SEM images of (b) random collagen fiber orientation from spontaneous solidified suspension; (c) aligned collagen fiber from magnetic field-directed solidified suspension. Confocal reflectance microscopy images of (d) random collagen fiber orientation from spontaneous solidified suspension; (e) aligned collagen fiber (light blue) from magnetic field-directed solidified suspension. Reproduced from [40], with permission from © 2016 American Chemical Society.

Figure 6

(a) Illustration of synthesis of PCBSA-@-nanodiamonds (NDs): 3-Amin-opropyltriethoxysilane (APTES) (i); 3(((benzylthio)carbonothioyl)thio)propanoic acid (BSPA) (ii); carboxybetaine methacrylate (CBMA) (iii); benzene sulfonamide (iv). (b) Schematic representation of the PCBSA-@-NDs’ performance at surface conversional charge and tumor cell uptake; (c) images of fluorescence microscopy for HepG2 treated with PCBMA-@-NDs at different pH values (scale is 50 µm). Reproduced from [82], with permission from © Higher Education Press 2020.

Figure 7

Representation of fluorescence “off” and “on” with the release of CPT from redox-responsive P(MACPTS-co-MAGP)@AgNPs nanoparticles. Reproduced from [88], with permission from © 2020 Elsevier.

Figure 8

A glucose-sensitive platform: schematic representation of (a) synthesis of glucose-responsive microspheres; (b) scaffold preparation. (c) The chemical structure of system components. SEM images of (d) surface, (e) cross-section, and (f) scaffold containing insulin-loaded microspheres. Reproduced from [105], with permission from © 2018 Elsevier.

Figure 9

The enzyme-sensitive nanosystem. (a) The illustration of the mechanism for obtaining LBL@MSN-Ag-Ti substrates. (b) Illustration of infection cure and bone tissue growth. (c) The osteogenic response after implantation in infected femurs in rats. (d) The antibacterial activity on the different implant surfaces after one week of implantation. Reproduced from [110], with permission from © The Royal Society of Chemistry 2020.

Figure 10

Scheme of internal and external multi-stimuli action in the case of a polymeric nanoparticle material. Reproduced from [127], with permission from © 2013 Elsevier.

Figure 11

A nanoplatform made of a silica-coated carbon nanocomposite with redox/NIR/pH stimuli-responsive release ability and superior chemo-photothermal combined antitumor treatment activity. (a) Schematic illustration of synthesis of DOX/MCN@Si-CDs and MCN@Si-CDs. (b) Schematic illustration of chemo-photothermal combined antitumor treatment. (c) Schematic therapy plan for in vivo treatments: ① intravenous injection in rat tail; ② NIR tumor irradiation. (d) Organs and tumor fluorescence images. (e) Excised tumors images. (f) Mice thermal imaging photographs. Reproduced from [136], with permission from © 2020 Elsevier.