Summary of bi-functional MFQDs developed for different biomedical applications in the last few years.

Types	Components	Sizes (nm)	Applications	Magnetic property	Ref.
Core–shell	CuInS2–Zn1−xMnxS	2.5–4	MR and fluorescence imaging of cancer cells	T 1 relaxivity (r1) (mM−1 s−1), ∼7.2	67
Mn doped QDs	Zn–Cu–In–(S,Se)/Zn1−xMnxS	8 ± 2	In vivo imaging of the regional lymph nodes in mice in both NIRFI and MRI	T 1-relaxivities up to 1400 mM−1 [QD] s−1 at 7 T and 300 K	68
Gd-based CuInS2/ZnS QDs	QD@PMO–Gd–FA	∼2.5	Dual modality magnetic resonance/optical imaging	T 1 relaxivity (r1 = 3.7231 mM−1 s−1)	137
Engineered Gd-doped CQDs	Gd-doped CDs	∼18	MR imaging-guided radiotherapy: in vivo evaluation of radiosensitivity in mice bearing herps tumors	r 1 relaxivity 6.45 mM−1 s−1	127
Silica nanohybrids integrated system	SiO2 nanohybrids containing CuInS2/ZnS QDs and Fe3O4	15–60	Cisplatin anticancer drug delivery into tumor cells for suppressing the growth of MCF-7 breast cancer cells	T 1 relaxivity (r1 = 214 mM−1 s−1)	136
Nitrogen, cobalt co-doped CQDs	N,Co-CDs	2–4.8	Detection of cholesterol and uric acid	Saturated magnetization value of 1.476 emu g−1 and a coercive force (Hc) of 9.68 × 103 Oe	128
Core–shell	Folic acid-conjugated ZnS : Mn/ZnS QDs	5.2 ± 1.0	Confocal microscopy with biphotonic excitation of T47D cancer cells	—	138
Ternary hollow nanospheres	Cd0.57Mn0.43S Cd0.29Mn0.71S	200–300	In vivo T 1-weighted transverse MR images of mouse liver	r 1 value 6.8 & 4.3 mM−1 s−1	139
Transition metal ion doped CQDs	Mn2+, Fe2+, Co2+, and Ni2+ doped C-dots	3.12, 2.73, 3.69, 2.72	In vivo magneto-fluorescent dual modality bioimaging of zebrafish	r 1 relaxivity: for Mn/C-dots & Ni/C-dots 0.341 and 0.356 mM−1 s−1, respectively	140
Core–shell	Fe3O4–CdSe	∼10	Nanosensing, molecular separation, and bio-assaying	Superparamagnetic at 300 K and become ferromagnetic at 5 K	111
Gd(iii) chelates functionalized CQDs	CQD–DTPA–Gd	4–6	Fluorescence and magnetic resonance dual-modal bioimaging	Longitudinal relaxivity 56.72 mM−1 s−1	135
Paramagnetic GQDs	Folate–GdGQDs	1.2	Dual-modality bioimaging and tumor-targeted drug delivery	Relaxivity r1 11.49 mM−1 s−1	141
Graphene oxide QDs decorated magnetic nanoplatform	GOQDs-coated amine functionalized MNPs	∼40	Efficient capture & two-photon imaging of rare tumor cells	Saturation magnetization of 37.8 emu g−1	142