Phyto-Engineered Gold Nanoparticles (AuNPs) with Potential Antibacterial, Antioxidant, and Wound Healing Activities Under in vitro and in vivo Conditions

Figures & data

Figure 1 UV-vis absorption spectra of Neat Acalypha indica leaf extract (curve A in black colour) and AuNPs synthesized from Acalypha indica (curve B in pink colour).

Abbreviations: AuNPs, gold nanoparticles; UV-vis, ultraviolet-visible.

Figure 2 XRD patterns of (A) Neat Acalypha indica leaf extract and (B) AuNPs synthesized from Acalypha indica. (* Bioinorganic constituents present in the extract).

Abbreviations: XRD, X-ray diffraction; AuNPs, gold nanoparticles

Figure 3 HPLC chromatogram profile of aqueous extract of Acalypha indica leaf at 340 nm; UV spectrum of aqueous Acalypha indica leaf extract (Inset Figure 3A).

Abbreviations: HPLC, high-performance liquid chromatography; UV, ultraviolet.

Table 1 Retention Time of Phytochemicals Present in the Acalypha indica Leaf Extract Observed at 340 nm

Compound No.	Retention Time (min)	Area %	Height %	Compound Identified	Number of Carbonyl Groups
1	4.842	28.454	29.694	Sildenafil citrate	4
2	5.142	35.951	29.385	Geniposidic acid	1
3	7.445	13.334	11.139	3,5-dimethylphenol	—
4	11.369	3.182	5.378	Palmitic acid	1
5	12.282	3.775	6.407	Borneol	—
6	13.252	5.776	8.932	2-Hexyl-1-octanol	—
7	14.331	9.528	9.065	α-Terpinyl acetate	1

Figure 4 FT-IR spectra of (A) Neat extract and (B) extract containing AuNPs synthesized from Acalypha indica.

Abbreviations: FT-IR, fourier transform-infrared; AuNPs, gold nanoparticles.

Figure 5 The proposed mechanism of reduction of gold ions to gold nanoparticles.

Figure 6 FE-SEM with EDAX images of AuNPs obtained from Acalypha indica (A and B) and HR-TEM with SAED images of AuNPs obtained AuNPs obtained from Acalypha indica (C and D).

Abbreviations: FE-SEM, field emission scanning electron microscope; EDAX, energy dispersive analysis of X-rays; HR-TEM, high-resolution transmission electron microscopy; SAED, selected area electron diffraction; AuNPs, gold nanoparticles.

Figure 7 SEM with EDAX images of (A and B) uncoated cotton, (C and D) neat extract-coated cotton and (E and F) extract containing AuNPs-coated cotton.

Abbreviations: SEM, scanning electron microscope; EDAX, energy dispersive analysis of X-rays; AuNPs, gold nanoparticles.

Figure 8 Antibacterial efficiency of AuNPs synthesized using Acalypha indica leaf extract prepared at 100 °C: (1) Uncoated cotton, (2) Extract-coated cotton, (3) Extract containing AuNPs-coated cotton.

Abbreviation: AuNPs, gold nanoparticles.

Figure 9 In vitro antioxidant activity of extract containing AuNPs.

Abbreviation: AuNPs, gold nanoparticles.

Figure 10 (A) Hematoxylin and Eosin stained microscopic images of regenerated structure of incised wounds on different days (3, 7 and 15) for treated with control, and extract containing AuNPs at 10x magnifications (scale bar 100 μm); (B) Histogram of re-epithelialization (in %); (C) Histogram of wound-cover area (in %).

Abbreviation: AuNPs, gold nanoparticles.

Figure 11 (A) Masson’s Trichrome staining images of regenerated structure of incised wounds in different days (3, 7 and 15) for treated with control, and extract containing AuNPs at 10x magnifications (scale bar 100 μm); (B) Histogram of collagen deposition (in %).

Abbreviation: AuNPs, gold nanoparticles.