Technetium-99m chelator-free radiolabeling of specific glutamine tumor imaging nanoprobe: in vitro and in vivo evaluations

Figures & data

Figure 1 Fourier transform infrared spectrum of (A) dendrimer-G₂, (B) glutamine, and (C) dendrimer–glutamine.

Figure 2 The ¹H-NMR spectrum of (A) glutamine, (B) dendrimer-G₂, (C) dendrimer–glutamine, and (D) ¹³C-NMR of dendrimer–glutamine.

Abbreviation: NMR, nuclear magnetic resonance.

Figure 3 Liquid chromatography-mass spectroscopy of glutamine conjugated to dendrimer-G₂.

Figure 4 Debye plot of glutamine conjugated to dendrimer-G₂.

Figure 5 (A) Size and (B) zeta potential. Red and black colors show the nanoconjugate and intact dendrimer, respectively.

Figure 6 Atomic force microscopy image of the (A) dendrimer and (B) nanoconjugate.

Figure 7 XTT assay: (A) A549 and (B) HEK-293 cells were exposed to the nanoconjugate for 24 and 48 hours.

Figure 8 Apoptosis/necrosis assay plots of A549 cells treated with 5.5 mg/mL of the nanoconjugate after 48 hours of incubation time.

Figure 9 In vitro stability of ^99mTc nanoconjugate complex in human serum at 37°C and PBS at room temperature.

Abbreviation: PBS, phosphate buffered saline.

Table 1 Biodistribution profile of nanoconjugate at different times (dose per gram of tissue). Data expressed as percentage ID⁄g±SD (n=3)

	1 h% ID/g	2 h% ID/g	3 h% ID/g
Liver	3.23±0.14	2.88±0.13	1.5±0.15
Kidney	4.57±0.03	3.71±0.13	2.64±0.12
Lung	1.88±0.02	1.39±0.07	0.91±0.07
Heart	3.90±0.02	3.83±0.009	2.10±0.03
Blood	1.92±0.12	1.15±0.01	0.50±0.1
Thyroid	0.71±0.13	0.50±0.06	0.46±0.07
Spleen	1.36±0.004	1.54±0.03	0.84±0.15
Intestine	0.76±0.06	2.13±0.02	1.90±0.09
Stomach	0.68±0.03	0.49±0.1	0.31±0.15
Bone (femur)	0.43±0.04	0.21±0.06	0.14±0.08
Muscle	2.06±0.08	2.85±0.07	2.28±0.05
Tumor	5.10±0.02	6.81±0.01	6.4±0.002
Tumor/muscle	2.47±0.07	2.38±0.04	2.8±0.05

Abbreviation: ID, injection dose.

Figure 10 Planar images with ^99mTc nanoconjugate in mice acquired at different time intervals up until 1 hour after injection: (A) anterior, (B) posterior. The arrows indicate the tumor site.

Figure 11 Transverse, sagittal and coronal imaging of nude mice bearing A549 tumor 1 hour after injection of 3.7 MBq of radiolabeled nanoconjugate. Arrows indicate the tumor position.

Figure 12 Tumor imaging of nude mice bearing A549 tumor 1 hour after injection of 3.7 MBq of ^99mTc nanoconjugate (A) without and (B) with coadministration of 10 mg/mL of glutamine (glutamine blocking). The arrows indicate the tumor site.

Figure 13 Biodistribution profile of nanoconjugate at different time intervals (dose per gram of tissue). P-value <0.05 was observed among various tissues.

Scheme 1 The preparation routes of dendrimer-G₂ and glutamine conjugation.

Abbreviations: DCC, N, N′-dicyclohexylcarbodiimide; DMSO, dimethyl sulfoxide.