## 2 Preparation of Magnetic-Fluorescent Nanocomposites
### Fluorescent Polymer Coated Magnetic Nanoparticles
#### 2.2.3 Polymer and QDs-Magnetic-Fluorescent Nanocomposites
Chitosan (CS) coated magnetic-fluorescent nanoparticles (CS-Fe\({}_{3}\)O\({}_{4}\)@ZnS:Mn) were synthesized in aqueous media under ambient pressure [64]. Chitosan encapsulated iron oxide, CdS QDs and podophyllotoxin were synthesised by [PERSON] et al. [65]. Fe\({}_{3}\)O\({}_{4}\) magnetic NPs acts as the magnetic targeting carrier and Gd(aspirin)\({}_{3}\)\(\cdot\)2H\({}_{2}\)O as the fluorescent-labelled drug. These two components were incorporated into chitosan microspheres to prepare magnetic and fluorescent chitosan microspheres as a drug delivery system [66]. Figure 7: Schematic diagrams illustrating surface functionalization of MNSs: (**a**) Conjugation of amine-functionalized quantum dots (QDs) to the surface of carboxylate-functionalized MNSs using conventional NHS/EDC coupling method; (**b**) PTX loading using a thin PLGA coat on the surface of QD-MNSs. Adapted from ref. [62]. Figure 8: Morphological and structural characterizations of CNT-SPIO (**a–d**) and CNT-SPIO-CdTe nanohybrids (**e–j**) prepared by LBLassembly in combination with covalent connection technique: (**a**) bright field TEM image of CNT-SPIO; (**b**) HRTEM image of CNT-SPIO; (**c,d**) EDX elemental mapping of C and Fe with a specific CNT-SPIO nanohybrid respectively; (**e**) bright field TEM image of CNT-SPIO-CdTe; (**f,g**) HRTEM images of CNT-SPIO-CdTe; (**h–j**) EDX elemental mapping of C, Fe and Cd with a specific CNT-SPIO-CdTenaohybrid respectively. Adapted from ref. [63]. The synthesis of a hydrophilic colloidal bimodal nanoprobe (FePt-CdS) was carried out through a seed-mediated nucleation and growth technique. In this synthesis of the complex nanostructure, glutathione (GSH) was used as the capping agent to render biocompatibility and dispersibility [67]. A chitosan-based drug delivery system, composed of Fe\({}_{3}\)O\({}_{4}\) magnetic NPs, CdTe@ZnS QDs and the anti-cancer drug DOX, was designed and fabricated by [PERSON] et al. [68]. A polymer solution of high molecular weight polystyrene, superparamagnetic magnetite NPs and coumarin-153 dye were used to prepare nanowires in the range of 200 nm in length. The material was prepared by a facile route using vacuum infiltration in porous alumina membranes. The resultant nanowires were functionalised with Inmonoglobulin-G and AntiCD54 antibodies to confer dual imaging and immunoresponse modality [69]. Rhodamine-coated cobalt ferrite magnetic fluorescent (MF) nanoparticles linked to a quenching molecular system containing a miR124a binding sequence (MF-miR124a beacon) were synthesized xdzsaw [70]. Superparamagnetic nanoparticles (20-40 nm) of maghemite, \(\gamma\)-Fe\({}_{2}\)O\({}_{3}\), with a well-defined stoichiometric structure, are synthesized by the borohydride reduction of ferric chloride at an elevated temperature (100 \({}^{\circ}\)C) followed by thermal treatment of the reaction product. The binding of the magnetic material with rhodamine B isothiamate results in the fluorescent magnetic nanocarrier providing, at the same time, a spacer arm for covalent immobilization of other biosubstances, including enzymes [71]. Water-soluble poly(poly(ethylenedyl)monomethacrylate)-grafted (P(PEGMA)-grafted) Fe\({}_{3}\)O\({}_{4}\) nanoparticles synthesized via a solvent-free atom transfer radical polymerization (ATRP) method were conveniently surface-modified with 3-aminopropyltrimethoxysilane as anchor molecules to donate NH\({}_{2}\) groups. Fluorescent magnetic NPs were then obtained by covalently bonding FITC to the NH\({}_{2}\) groups (Figure 9) [72]. [PERSON] et al. used a second-generation photosensitizer Chlorin e6 (Ce6) that was covalently conjugated to the surface of the magnetic nanoparticles with a silane coupling agent. Ce6 molecules retained their spectroscopic properties and functionalisation to be used in various imaging applications [73]. [PERSON] et al.