Highly stable gold nanoparticles green-synthesized by upcycling cartilage waste extract from yellow-nose skate (Dipturus chilensis) and evaluation of its cytotoxicity, haemocompatibility and antioxidant activity

Figures & data

Figure 1. The schematic representation for the synthesis of sk-AuNPs and cf-sk-AuNPs.

Table 1. Amino acid composition analysis of the extract.

Amino acids	Concentration (µg/mg extract)
Cys	1.60
Asp^a	30.5
Glu^b	49.9
Ser	26.3
Gly	89.2
His	30.2
Arg	31.3
Thr	18.1
Ala	35.2
Pro	41.6
Tyr	6.60
Val	15.6
Met	9.90
Ile	13.6
Leu	20.4
Phe	13.4
Trp	1.10
Lys	20.4

^a The sum of aspartate and asparagine.

^b The sum of glutamate and glutamine.

Figure 2. UV–visible spectra of sk-AuNPs.

Figure 3. HR-XRD pattern of cf-sk-AuNPs.

Figure 4. HR-TEM images of sk-AuNPs. The scale bars represent (A) 20 nm, (B) 50 nm and (C) 2 nm. The distances between two neighbouring lattice fringes were measured as 0.23 nm and 0.25 nm. (D) Size histogram of sk-AuNPs.

Figure 5. HR-TEM images and size histogram of cf-sk-AuNPs. After the centrifugation of sk-AuNPs, the pellet was recovered and re-dispersed in (A, B and C) deionised water, (D, E and F) PBS and (G, H and I) full media.

Table 2. On-the-shelf colloidal stability of cf-sk-AuNPs for 27 days.

		Day 0	Day 2	Day 6	Day 13	Day 20	Day 27	Average
UV–visible spectra	λmax (nm)	543	543	542	543	542	543	543
	Absorbancemax (AU)	1.1	1.1	1.1	1.1	1.1	1.1	1.1
Hydrodynamic size (nm)	Effective diameter (nm)	243.4	220.7	203.7	185.9	202.9	198.0	209.2 ± 20.1
	Polydispersity index	0.21	0.21	0.21	0.21	0.19	0.20	0.2 ± 0.01
Zeta potential (mV)		−42.8	−39.7	−44.3	−39.4	−37.1	−41.4	−40.8 ± 2.6

Figure 6. Colloidal stability of sk-AuNPs in PBS, DMEM and full media. sk-AuNPs were centrifuged and re-dispersed in the following solutions: (A and B) PBS, (C and D) DMEM and (E and F) full media. (A, C and E) UV–visible spectra and (B, D and F) hydrodynamic size were measured over 48 h on the shelf.

Table 3. Colloidal stability of sk-AuNPs which were centrifuged and re-dispersed in PBS, DMEM and full media.

			0 h	24 h	48 h
In PBS	UV–visible spectra	λmax (nm) of SPR	538	538	538
	Hydrodynamic size	Effective diameter (nm)	292.4	298.9	295.2
		Polydispersity index	0.27	0.27	0.30
In DMEM	UV–visible spectra	λmax (nm) of SPR	541	539	545
	Hydrodynamic size	Effective diameter (nm)	284.8	369.5	736.8
		Polydispersity index	0.26	0.24	0.29
In full media	UV–visible spectra	λmax (nm) of SPR	540	540	539
	Hydrodynamic size	Effective diameter (nm)	287.5	266.9	272.8
		Polydispersity index	0.27	0.27	0.28

Figure 7. In vitro antioxidant activity (DPPH radical scavenging activity) of cf-sk-AuNPs.

Table 4. DPPH radical scavenging activity of cf-sk-AuNPs.

cf-sk-AuNPs (Au concentration, μg/mL)	Radical scavenging activity (%)	VCEAC (μM)
15.7	9.7	36.3
31.4	13.1	43.6
62.7	26.6	72.2
125.5	37.2	95.9
251.0	63.2	149.6

VCEAC: vitamin C equivalent antioxidant capacity.

Figure 8. Cytotoxicity of cf-sk-AuNPs on seven cancer cells. (A) A549, (B) AGS, (C) HeLa, (D) HepG2, (E) HT29, (F) MDA-MB-231 and (G) PANC-1.

Figure 9. Cell morphology of HeLa cells with different concentrations of Au. (A) 0 μg/mL, (B) 16 μg/mL, (C) 32 μg/mL, (D) 63 μg/mL and (E)126 μg/mL.

Figure 10. Haemocompatibility assay.