The Control of the Adsorption of Doxorubicin on Gold Surfaces Tracked by Surface-Enhanced Raman Scattering Spectroscopy

Pessanha, Pedro Victor A.; Sant’Ana, Antonio Carlos

doi:10.21577/0103-5053.20250121

Figures (6)
Tables (1)

Figure 1 (A) UV-Vis-NIR spectra of (a) DOX 1.0 × 10^-4 mol L^-1 aqueous solution; (b) AuNP aqueous suspension; (c) adsorption kinetic of DOX 1.0 × 10^-4 mol L^-1 on AuNP (ten overlapped spectra taken during 1 h); (d) sum of “a” and “b” spectra. Size distributions of unmodified AuNP against (B) scattered light intensity and (C) number of particles.

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Figure 2 UV-Vis-NIR spectra from aggregation kinetics of AuNP, after addition of (a) KCl aqueous solution at 1.0 × 10^-3 mol L^-1 final concentration; (b) ME ethanolic solution at 1.0 × 10^-8 mol L^-1 final concentration.

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Figure 3 (a) Molecular structure of DOX, indicating the anthraquinone portion (AP), I, II, III and IV rings, side chain (SC) and sugar moiety (SM); (b) optimized DOX geometry and (c) its electrostatic potential surface at B3LYP/6-31+G(d,p) level of theory; (d) optimized geometry of DOX interacting with Au₆ cluster at B3LYP/6-31+G(d,p)/LanL2DZ level of theory.

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Figure 4 Raman spectra of DOX in solid state, by using (a) 1064 nm and (b) 785 nm laser lines; (c) RR spectrum of DOX in 1.0 × 10^-3 mol L^-1 aqueous solution, excited in 632.8 nm; (d) simulated Raman spectrum of DOX.

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Figure 5 (a) Raman spectra of DOX in solid state; SERS spectra of DOX 1.0 × 10^-5 mol L^-1 on AuNP surface, in aqueous suspensions (b) modified with KCl 1.0 × 10^-3 mol L^-1 and (c) modified with ME 1.0 × 10^-8 mol L^-1. All Raman and SERS spectra exciting with λ₀ = 1064 nm. Insert: schematic representations of adsorption geometries of DOX on AuNP surfaces, for each SERS pattern.

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Figure 6 (a) RR spectra of DOX in 1.0 × 10^-3 mol L^-1 aqueous solution; SERRS spectra of DOX 1.0 × 10^-5 mol L^-1 on AuNP surface, modified with KCl 1.0 × 10^-3 mol L^-1 (b) in suspension and (c) as dried film (average spectrum, see Figure S1). All Raman and SERRS spectra excited with λ₀ = 632.8 nm.

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Table 1 Tentative assignment of Raman and SERS bands present in the spectra of DOX and corresponding calculated frequencies

Raman (solid) 1064 nm / cm^-1	Raman (aq) 632.8 nm / cm^-1	SERS (KCl aq) 632.8 nm / cm^-1	SERS (KCl film) 632.8 nm / cm^-1	SERS (KCl aq) 1064 nm / cm^-1	SERS (ME aq) 1064 nm / cm^-1	Raman (theor.) / cm^-1	Assignment
1731	-	-	-	-	-	1806	ν(CO)_SC
1644	1667(sh)	1660(sh)	1669(sh)	1685	1673(sh)	1681	ν(CO) + ν(CC)_AP
1609	1638	1637	-	1641	1654	1641	ν(CC)_{Ring III} + δ(COH)_{Ring III}
-	-	-	-	1618	1607	1627	ν(CC)_{Ring I} + ν(CC)_{Ring III}
1581	1575	1577	1571	1583	1575(sh)	1625	ν(CC)_{Ring I} + ν(CC)_{Ring III} + δ(NH₃)
1462	-	-	-	1452	1466	1513	ν(CC)_AP + ν(CO) + δ(COH)_{Ring III} + δ(CH₃)_Metoxi
1439(sh)	1437	1432	1443	-	-	1473	δ(CH₃)_Metoxi + δ(CH)_{Ring IV} + δ(CH)_SC
1427	1410(sh)	1410(sh)	1407	1419	1416	1410	δ(CH₃)_Metoxi + ν(CC)_{Ring II} + δ(NH₃) + δ(CH)_SC
1291	1299	1287	1296	-	1299	1329	ν(CC)_AP + ω(CH₂) + δ(OH)_{Ring III} + τ(NH₃)
1251	-	-	-	1284	1283	1260	ν(CC)_AP + τ(CH₂)
1233	1238(sh)	1234(sh)	1258	-	-	1257	ν(CC)_AP + τ(CH₂) + τ(NH₃)
1205	1209	1202	1220	1138	-	1233	ν(CC)_AP + ν(CO)_Metoxi+ ν(CN)
1087	1079	1070	1096	1080	1084	1105	ν(CC)_AP + ν(CO)_SC,Metoxi
991	991	979	989	-	1014	1009	ν(CN) + ν(CC)_{Ring I} + ν(CO)_SM,Metoxi
875	-	-	-	-	826	881	δ(CC)_AP + γ(CC)_AP + ν(CC)_SM
796	-	-	-	796	799	801	γ(CC)_AP + ν(CC)_SM
503	-	-	-	507	494	505	ν(CC)_{Ring II/III} + ν(CC)_{Ring I} + δ(CCO)
466		-	-	-	-	474	ν(CC)_{Ring II/III} + δ(OH)
450		-	-	-	-	465	γ(CC)_AP
443 (sh)	437	433	449	465	455	449	ν(CC)_{Ring II/III} + δ(CC)_{Ring IV}
346	347	-	-	-	-	353	γ(CC)_AP + ν(CC)_SM

The Control of the Adsorption of Doxorubicin on Gold Surfaces Tracked by Surface-Enhanced Raman Scattering Spectroscopy

Abstract