Ag Colloidal Solution Research Articles

A simple green synthesis of pure and sterling silver nanoparticles via pulsed laser ablation in deionized water: characterization and comparison

Pure silver (Ag) and its alloy nanoparticles (NPs) with intense and tunable SPR bands in the visible region are widely exploited for biosensors, information storage, and solar energy systems. Pure Ag and Sterling silver (Ag92.5Cu7.5) NPs were synthesized by the laser ablation method in deionized water using a pulsed Nd:YAG laser. The prepared NPs were characterized and compared for their structural, morphological, and optical properties. The x-ray diffraction (XRD) and selected area electron diffraction (SAED) results revealed that the NPs have polycrystalline nature with five lattice directions. The diffraction peak positions for Ag92.5Cu7.5 NPs exhibited an average redshift of 0.1 ̊ compared to pure Ag NPs due to the presence of copper atoms in the composite crystal unit cell structure. The formation of spherical NPs with an average size of 9.1 nm and 8.4 nm for Ag and Ag92.5Cu7.5 NPs was confirmed using transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). It was found that the concentration of synthesized Ag92.5Cu7.5 alloy NPs was considerably higher than that of pure Ag NPs. Going from pure to alloy silver NPs, the wavelength of surface plasmonic resonance (SPR) peak shifted from 400 nm to 395 nm. The UV–vis absorption spectra at different aging times revealed that pure Ag colloidal solution is relatively stable. Both colloidal solutions exhibited a similar pattern of photoluminescence (PL) emission spectra with peaks in the blue region.

Effect of Au and Ag nanoparticles addition on the morphological, structural and optical properties of ZnO thin films deposited by sol-gel method

In the present study, ZnO thin films were deposited on quartz substrates by sol-gel spincoating method. Zinc-diacetate ((Zn(CH3COO)2.2H2O), diolamine (DEA) (HN(CH2CH2OH)2) and ethylene glycol monomethyl ether (CH3OCH2CH2OH) were used as a precursor, stabilizer agent, and solvent, respectively. Au and Ag NPs were synthesized by (PLAL) technique using “Q-Switched ND-YAG laser” system with laser parameters (520 mJ laser energy, 1064 nm wavelength, 450 laser pulses, and 1Hz frequency). The volumetric ratios of ZnO source solution to Au and Ag colloidal solutions were 3:2 and 4:1, respectively. The morphological, structural and optical properties of ZnO thin films embedded with Au and Ag NPs were investigated. The patterns of x-ray diffraction (XRD) showed peaks indexed to (100), (002) and (101) planes for ZnO and (111), (200) and (220) for Au and Ag NPs. The surface morphology of the films was examined by FESEM and the Raman spectra of ZnO thin films embedded with Ag and Au NPs were investigated. Furthermore, the optical properties of the films were analyzed by UV-Vis spectroscopy measurements. The optical band gap of the films increased with increasing the volumetric ratios of ZnO embedded with Au and Ag NPs.

Synergistic Effect of Field Emission Properties on Growth of CNTs by One-Pot Preparation of Various Concentrations Composite Catalyst

Multi-walled carbon nanotubes (MWCNTs) were grown on Silicon (Si) substrate by using low-pressure chemical vapor deposition (LPCVD) technique where iron (Fe) and silver (Ag) colloidal solution act as a catalyst were prepared by chemical route. The as-prepared solutions in varied concentrations were deposited on a Si substrate using a spin coating process at 700[Formula: see text]rpm. The purpose of Fe in composite catalysts is to have high carbon solubility and diffusion rate, and Ag utilization can change catalyst activity temperature and enhance carbon yields. In this work, we demonstrate the growth of carbon nanotubes (CNTs) on different catalyst concentrations ([Formula: see text]Fe/[Formula: see text]Ag), ([Formula: see text]Fe/[Formula: see text]Ag), ([Formula: see text]Fe/[Formula: see text]Ag) and ([Formula: see text]Fe/[Formula: see text]Ag) catalytic films. Field Emission Scanning Electron Microscopy (FESEM) was used to image the morphologies of various catalyst concentrations MWCNTs. The natures of the synthesized CNTs were determined using Raman spectroscopy and it was revealed that as-prepared CNTs are MWCNTs due to the absence of radial breathing mode (RBM). Raman spectroscopy demonstrated the lower ID/IG ratio (Ratio of the intensity of D-Raman peak and G-Raman peak) of ([Formula: see text]Fe/[Formula: see text]Ag) MWCNTs. The ID/IG ratio for ([Formula: see text]Fe/[Formula: see text]Ag) catalyzed MWCNTs was 0.76, while the ID/IG ratio for ([Formula: see text]Fe/[Formula: see text]Ag) catalyzed MWCNTs was 0.89. The ([Formula: see text]Fe/[Formula: see text]Ag) catalyzed MWCNTs were found to be more defective as compared to other. Electron Emission from ([Formula: see text]Fe/[Formula: see text]Ag) catalyzed MWCNTs were much stronger than from other samples, as demonstrated by Field Emission measurement using diode configuration. The turn-on field for ([Formula: see text]Fe/[Formula: see text]Ag) catalyzed MWCNTs was (0.92 V/[Formula: see text]m) which is slightly lower than that of ([Formula: see text]Fe/[Formula: see text]Ag) catalyzed MWCNTs (1.83 V/[Formula: see text]m), indicating superior enhancement.

Distance Learning: Homemade Colloidal Silver

To continue the experimental education of Chemical Engineering students during the SARS-Covid 19 pandemic, our school opted for assembling laboratory kits for each one of them and sending them by courier service to their homes. This arose much interest and was particularly successful in an Electrochemistry and Corrosion elective course, because up to 25 experiments were performed in each of the Fall 2020 and Spring 2021 semesters. By having their kits at home, students were also able to design experiments on their own. One such experiment –the preparation of a colloidal silver solution– only required readily available kit materials and some other home and kitchen items to produce an easily observable Ag colloidal solution. Lower classes (e.g., General Chemistry, High School Chemistry) should be able to reproduce this experiment as well. The entire procedure can be completed in 1 h.

Green synthesis of well-dissolved high-stable silver nanoparticles using hydroxypropylmethyl cellulose as a protective agent

This paper presented the synthesis of Ag nanoparticles (Ag NPs) by the chemical reduction method which is simple and environmentally friendly. Silver nitrate, hydroxypropylmethyl cellulose (HPMC), and glucose were used as silver precursors, protective agents, and reducing agents, respectively. The effects of AgNO3 concentration, glucose concentration, HPMC content, reaction time, and reaction temperature on the formation of Ag NPs were investigated. The properties of Ag NPs were analyzed by transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy, and X-ray diffraction (XRD). The results indicated that when the HPMC content was 0.01%, AgNO3 concentration was 0.05 M and glucose reducing agent concentration was 0.4%, the best reaction occurred in 9 hours at 90oC. The Ag NPs prepared under HPMC protection possessed a face-centered cubic crystal structure (FCC), a spherical shape having average sizes in the range of 8 ‒ 12 nm. The Ag colloidal solution had a suitable zeta potential (-37.21 mV) to maintain the stability and to avoid the agglomeration of Ag NPs. In addition,the paper proposed a method to indirectly determine the Ag NPs content through the separation of Ag NPs from the colloidal solution by coagulation, using the electrolyte Al(NO3)3.9H2O.

Synthesis of silver and gold nanoparticles by pulsed laser ablation for nanoparticle enhanced laser-induced breakdown spectroscopy

Chemically pure colloidal suspensions of silver and gold nanoparticles were synthesized by nanosecond pulsed laser ablation of metal plates placed in the ultrapure water. The nanoparticles were analyzed by UV-Vis spectroscopy and electron microscopy. The absorption spectra of silver and gold nanoparticles were basically the same as that of the chemically prepared nanoparticles. The diameter of almost spherically shaped Ag and Au nanoparticles prepared by 40 mJ laser energy was in the range of approximately 20–100 and 20–50 nm, respectively. The microdrops of Ag and Au colloidal solution were deposited on the surface of soda-lime glass and copper to perform nanoparticle-enhanced laser-induced breakdown spectroscopy. The results showed that Au nanoparticles cause much higher spectral enhancement, from both glass and copper targets, as compared to that of Ag nanoparticles. For the given target, type of nanoparticle and laser fluence, the enhancement factor of various spectral lines of an element was not the same. Moreover, the enhancement factor found to decrease with an increase of laser fluence, which is explained in terms of the electric field reduction due to the flow of electrons between two adjacent nanoparticles.

Synthesis of Au-Ag Alloy Nanoparticles in Deionized Water by Pulsed Laser Ablation Technique.

Au-Ag alloy nanoparticles are physically synthesized using rapid, simple and efficient Q-switched Nd:YAG pulsed laser ablation in liquid technique (PLAL). Au and Ag colloidal solutions are separately prepared by 1064 nm laser ablation of metallic target (gold and silver) which is immersed in deionized water. Au-Ag alloy nanoparticles are prepared by irradiating the mixture of Au and Ag colloidal solutions with 532 nm of second harmonic wavelength of Nd:YAG laser at three different ratio, 3:1, 1:1 and 1:3 within different exposure times. The three of plasmon absorption bands of Au-Ag nanoparticles are shifted linearly to the lower wavelength [499.67 nm (3:1), 481.25 nm (1:1), 467.91 nm (1:3)], as compared to plasmon absorption spectra of pure Au (520 nm) and Ag (400 nm). Moreover, the change in colors are also observed from red (Au) and yellow (Ag) to orange, brown and green color due to the Au-Ag alloy formations, respectively. Transmission electron microscopy shows the Ag shell around the inner core of Au spherical metal with broad size distribution due to the three different volume ratio, respectively (1.7 nm, 0.7 nm, 1.4 nm). Energy-dispersive X-ray spectroscopy analysis confirms the presence of Au and Ag elements in Au-Ag alloy nanoparticles without any contaminations. Attenuated total reflectance fourier transform infrared spectroscopy analysis also confirms the homogenous Au-Ag alloys chemical bonding.

Development of Synergistic Antimicrobial Coating of p-Aramid Fibers Using Ag Nanoparticles and Glycidyltrimethylammonium Chloride (GTAC) without the Aid of a Cross-Linking Agent.

Functional p-aramid fibers that can express antimicrobial activity were produced by simple processing of silver nanoparticles (AgNPs), which are well known as antimicrobial agents, by using glycidyltrimethylammonium chloride (GTAC), a quaternary ammonium salt. P-aramid fibers were treated with GTAC by the pad-dry-cure process and put into an Ag colloid solution for reactions at 40 °C for 90 min to prepare GTAC/AgNPs-treated p-aramid fibers. Through these processes, GTAC was used as a substitute for existing cross-linking agents. The changes in the degree of attachment of AgNPs to the surface of p-aramid fibers were determined using a scanning electron microscope according to parameters such as GTAC concentration, Ag colloid concentration, and reaction temperature. Through this study, the following results were obtained: (i) The tensile strength of AgNPs/GTAC-treated p-aramid fibers was found to be about 80% of that of untreated p-aramid fibers; (ii) Thermogravimetric analysis showed that the thermal stability of p-aramid fibers did not change much after GTAC/AgNPs treatment and (iii) Antimicrobial activity analysis showed that AgNPs/GTAC-treated p-aramid fibers exhibited superior antibacterial properties compared to untreated p-aramid fibers, which may or may not be the effect of GTAC or AgNPs, or both.

Label-Free Optical Detection of Acute Myocardial Infarction Based on Blood Plasma Surface-Enhanced Raman Spectroscopy

This study is intended to explore the potential of silver (Ag) nanoparticle-based plasma surface-enhanced Raman spectroscopy (SERS) for providing a rapid and simple "Yes/No" assessment to detect acute myocardial infarction (AMI). A simple, rapid, and accurate method of diagnosing AMI is critical to reduce mortality and improve prognosis. Techniques such as electrocardiography examination and use of cardiac troponins have not yet met the current clinical need. Therefore, alternative approaches need to be developed. Plasma samples from 32 patients with AMI and 32 healthy control (Clt) subjects were assessed. Multivariate statistical techniques, including principal component (PC) analysis and linear discriminant analysis (PCA–LDA), were employed to develop a diagnostic algorithm for differentiating between patients with AMI and Clt subjects. Furthermore, the receiver operating characteristic was tested to evaluate the performance of the PCA–LDA algorithm for AMI detection. Each plasma sample was mixed with an equal volume of Ag colloidal solution, and the SERS measurement of each plasma sample was performed. The plasma SERS spectrum showed much stronger and sharper peaks compared with the normal Raman spectrum. Tentative assignments of Raman spectroscopy bands showed specific biomolecular (e.g., proteins, adenosine, adenine, and uric acid) changes. PC analysis and LDA were employed to discriminate patients with AMI from Clt subjects, yielding a sensitivity of 87.5% and a specificity of 93.8%. The findings of this study suggest that plasma SERS has a great potential for improving AMI in the future, and this will certainly reduce the difficulty, time to draw blood, and patients’ pain to a great extent.

Interaction of a converging laser beam with a Ag colloidal solution during the ablation of a Ag target in water

We studied the nanosecond laser-induced shape modifications of Ag colloids exposed to a converging laser beam during the ablation of a Ag target in water. To this end, we performed a series of laser ablation experiments in which the laser energy was varied while all other parameters were kept constant. In addition to transmission electron microscopy (TEM), the shape distribution of the Ag nanoparticles was determined by modelling the extinction spectra of the final colloidal solutions using theoretical calculations based on shape distributed effective medium theory (SDEMT). From these calculations, two physical parameters named sphericity and dispersity were introduced and used to gauge the evolution of the shape distribution of the particles. As the laser energy on the target was increased from 5 to 20 mJ/pulse, an apparently abrupt modification of the shape distribution of the particles was evidenced by both TEM and SDEMT calculations. This change is explained in terms of competitive fragmentation, growth and reshaping processes. On the basis the heating–melting–vaporization model, we demonstrate how the competition between these processes, occurring at different locations of the converging beam, determines the shape distribution of the final product. We highlight the relevance of the fluence gradient along the beam path and the laser interaction volume on the laser-induced modifications of the suspended particles during the ablation process.

Plasmonic ELISA based on the controlled growth of silver nanoparticles.

Herein, we demonstrate a plasmonic ELISA based on the alkaline phosphatase (ALP)-mediated growth of silver nanoparticles (AgNPs) for the sensitive, rapid, and naked-eye detection of cancer biomarkers in clinical serum samples. This approach was used to measure the low-abundance alpha fetal protein (AFP) in clinical sera, which demonstrates its great capability in the differentiation of cancers and evaluation of therapeutic responses. Impressively, the readout of the plasmonic assay depends on the rapid formation of Ag colloidal solutions with various degrees of yellow color, which can be distinguished by the naked eye, without the need for sophisticated platforms. The limit of detection of the plasmonic ELISA for alpha fetal protein (AFP) can be as low as 0.23 ng mL-1, which is approximately 10 folds lower than that of conventional ELISA. This plasmonic ELISA opens a new avenue for the early detection of cancers and monitoring of cancer reoccurrence especially in resource-poor regions where convenient diagnostic tools are highly desirable.

Synthesis of Ag@Cu2O core-shell metal-semiconductor nanoparticles and conversion to Ag@Cu core-shell bimetallic nanoparticles

Ag@Cu2O core-shell metal-semiconductor nanoparticles (NPs) were prepared by using solution phase strategy. It was found that Ag@Cu2O core-shell NPs were easily converted to Ag@Cu bimetallic core-shell NPs with the help of surfactant PVP and excessive reducer ascorbic acid in air at room temperature, which is a unique phenomenon. Varying volumes of Ag colloidal solutions were added into the reaction mixtures containing fixed initial concentrations of Cu2+ and PVP, Ag@Cu2O and Ag@Cu core-shell NPs with fixed core size but varying outer shell thicknesses could be obtained. The composites, structures, morphologies and extinction properties of Ag@Cu2O and Ag@Cu core-shell NPs were systematically characterized by XRD, TEM and extinction spectra. Both of these NPs show wide tunable optical properties. The extinction peaks could be shifted from 421 nm to 700 nm. FTIR results reveal that Cu+ ions on the surface of Cu2O nanocrystalline coordinate with N and O atoms in PVP and further are reduced to metallic Cu by excessive ascorbic acid and then form a nucleation site on the surface of Cu2O nanocrystalline. PVP binds onto a different site to proceed with the reduction until all the Cu sources in Cu2O NPs are completely assumed. And the shell of Cu2O is converted to Cu shell. The synthesis approach in this paper is simple and also a promising reference for synthesizing other core-shell NPs. Ag@Cu2O NPs can be easily converted to Ag@Cu NPs in air at room temperature, which is promising to be used in electronic devices.

Agglomeration in core-shell structure of CuAg nanoparticles synthesized by the laser ablation of Cu target in aqueous solutions

Metallic copper Cu and bimetallic copper–silver CuAg nanoparticles (NPs) are generated by the ablation of copper bulk target in water and aqueous Ag colloidal solution, respectively. The experiments were performed using nanosecond Nd:YAG laser operating at 1064 nm. The generated NPs are characterized by UV–vis absorption spectroscopy, laser-induced breakdown spectroscopy, dynamic light scattering and scanning electron microscopy. The conducted investigations can be summarized as follows: (i) CuAg NPs colloidal solution possess the absorption in UV–vis spectral region, which can be attributed to the Cu-component; (ii) the primary bimetallic CuAg NPs have near uniform dimensions with diameter of about 15 nm, and as a rule, they are grouped into larger agglomerates without defined morphology; (iii) the obtained Cu NPs have mainly spherical form with average diameters up to 20 nm. Both types of NPs show a tendency towards the formation of large agglomerates with different morphology. Bimetallic NPs show the plasmon resonance in the vicinity of 640 nm with a good coincidence with formation of the colloidal solution of pure Cu NPs. The results also demonstrate that the core–shell structure (Ag-rich core/Cu-rich shell) is important for the formation of the bimetallic NPs, also agreeing very well with theory.

Au/Ag composite nanorings based on galvanic reaction of the Ag nanoparticles induced by laser ablation in water

A simple route is presented to fabricate Au/Ag composite nanorings based on the galvanic reaction of the silver colloidal solution by addition of chloroaurate solution. The silver colloidal solution with near monodispersion in size is firstly prepared by laser ablation of Ag target in pure water and subsequent additional irradiation. It has been found that addition of chloroaurate solution to the Ag colloidal solution can produce the Au/Ag composite nanoparticles, which are the ring-like Ag single crystals embedded with ultrafine Au nanoparticles. Further experiments have revealed that appropriate molar ratio of Au to Ag in the solution and round original Ag nanoparticles are crucial to formation of such composite nanorings. This study provides a simple way to fabricate noble metal nanorings with different sizes. Such composite nanorings have exhibited the surface plasmon resonance properties in near-infrared (NIR) bands and could thus be used as the NIR-excited surface enhanced Raman scattering (SERS) substrates for detection of trace amount molecules and some other nanophotonic devices.

Au nanoparticle-built mesoporous films based on co-electrophoresis deposition and selective etching

A simple and facile strategy is presented to fabricate mesoporous Au spherical nanoparticle films based on the combination of co-electrophoresis deposition in the mixed colloidal solutions of Au and Ag and selective etching of the Ag nanoparticles which act as a sacrificial metal. The film is homogeneous in the macroscale but with numerous nanoscaled pores. The film configuration can be easily tuned by the size of Au colloidal nanoparticles and the amount of Ag colloidal solution mixed. Importantly, such structured mesoporous film exhibits strong surface-enhanced Raman scattering activity with good reproducibility and repeatability. Additionally, this study provides a novel method for the controllable construction of other mesoporous films from simple metals to multicomponent hybrids, by using nanoparticles as building blocks.

Ag/DNQ-novolac-based nanocomposite films for controllable UV lithography morphological patterning

In this study, the detailed characterisation of silver (Ag) nanoparticles/polymer nanocomposite chemical structure and morphology of grating has been carried out. Scanning electron microscopy measurements show spherical shape of Ag nanoparticles (40–80 nm in diameter) prepared in chloroform by reduction of silver nitrate. In the positive photoresist based on 2-diazo-2H-naphthalen-1-one (DNQ)–novolac, Ag nanoparticles were deposited from organic colloidal solution. The content of nanoparticles in the polymer matrix was varied by increasing the concentration of Ag colloidal solution. Grating was formed by contact lithography. The quantification of Ag nanoparticles and chemical analysis of Ag/DNQ-novolac-based nanocomposite was performed by means of energy dispersive X-ray analyzer and SEM/EDS. In order to study the effect of Ag nanoparticles on the DNQ-novolac-based nanocomposite structure, investigations with Fourier transform infrared spectroscopy were conducted. Ag nanoparticles cause changes associated with substituent-sensitive out-of-plane C–H bending vibrations of aromatic ring. Ag/DNQ-novolac-based nanocomposite film surface morphology and grating topography imaging were performed using atomic force microscopy. Added Ag nanoparticles change the geometrical parameters of the gratings. The split of corrugations was achieved in Ag/DNQ-novolac-patterned films. Their morphology can be tailored by altering the content of Ag nanoparticles.

Systematic preparation of colloidal silver nanoparticles for effective SERS substrates

Optimized parameters to produce aggregated silver colloidal nanoparticles in solution for the effective surface-enhanced Raman scattering (SERS) substrates were systematically determined. The sizes of the prepared silver nanoparticles were identified in TEM images, which were 31±5nm and almost all of them were aggregated in three or four particles in solution. The optimum condition was determined by relative enhancement of the SERS signal in the spectra of benzoic acid. The observed SERS signals in the prepared solution were remarkably reproducible and the solution was stable for a week at least. The SERS spectrum of biphenyl carboxylic acid in Ag colloidal solution prepared in the present method was obtained for comparison to the one previously reported. In addition, the SERS spectrum of 4,4’-biphenyl dicarboxylic acid was measured for the first time in solution and spectral assignments were provided.

Evaluation of Optical Properties of Ag, Cu, and Co Nanoparticles Synthesized in Organic Medium

The surface plasmon resonance evaluation of colloidal metal nanoparticles, synthesized in organic medium, is reported in this work. Metal salts were dissolved in dioxane/AOT solution and reduced by hydrazine hydrate under vigorous stirring. Optical properties of obtained colloidal nanoparticles were investigated by UV VIS spectroscopy. Theoretical predictions of optical properties of metal nanoparticles were made by means of the Mie theory and the Drude free-electron model. Geometrical parameters and distribution of metal nanoparticles in colloidal solutions were characterized by atomic force microscopy. The results show that Ag, Cu, and Co nanoparticles, synthesized in organic medium distinguish plasmonic properties. Surface plasmon resonance bands were obtained in all cases: Ag at 430 nm, Cu at 570 nm, Co at 350 nm (SPR1) and 430 nm (SPR2). Comparing theoretical evaluation of nanoparticles size with atomic force microscopy analysis, we can assume that our calculations are accurate. It was found that dominating nanoparticles diameter in Ag colloidal solution is ≈ 150 nm, in Cu colloidal solution is ≈ 70 80 nm and in Co colloidal solution is ≈ 150 nm. It can be concluded that nanoparticles with enhanced plasmonic properties synthesized in organic medium can be widely used in order to increase e ciency of various optical elements.

Synthesis and characterization of L-histidine capped silver nanoparticles

L-histidine capped Ag nanoparticles have been synthesized by a hydrothermal method. Spherical Ag nanoparticles with average diameter ranging from 9 to 21nm can be obtained by tuning the reaction pH and the reactant ratio. The topography, surface and internal structures of the histidine capped Ag nanoparticles have been characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering, X-ray photoelectron spectroscopy (XPS), X-ray Diffraction (XRD), Raman spectroscopy and UV–vis absorption spectroscopy. Surface enhanced Raman scattering (SERS) results revealed that the Ag colloid in present study have a structure that the imidazole moiety of histidine is bound on the Ag surface and COO− group is exposed outward. The as-synthesized Ag colloidal solution was very stable and can be stored at room temperature at least one month. In addition, it was found that the solution color of Ag colloid can change from yellow to reddish-brown by addition of the NiCl2 solution, which may have potential application for Ni2+ detection.

SERS Microspectroscopy of Biomolecules on Dried Ag Colloidal Drops

We report the application of dried Ag hydroxylamine‐reduced colloidal drops to surface‐enhanced (resonance) Raman scattering (SE(R)RS) study of biomolecules using Raman microspectroscopy. 5,10,15,20‐tetrakis(1‐methyl‐4‐pyridyl)porphyrin (TMPyP), amino acid tryptophan, and phospholipid 1,2‐distearoyl‐sn‐glycero‐3‐phosphocholine (DSPC) served as testing biomolecules. Ag colloid/biomolecule drop dried on glass support forms a ring in the edge part of the drop in which almost all nanoparticles are clustered. This specific drying process promotes adsorption of the studied biomolecules in highly enhancing sites (“hot spots”) as well as concentrates them in the ring. We were able to obtain SE(R)RS spectra from the ring that cannot be acquired directly from Ag colloidal solutions (SERRS spectrum of 1 × 10−10 M TMPyP by 1 s accumulation time, SERS spectrum of 2 × 10−7 M DSPC). Despite the spectral irreproducibility and problems with spurious bands in some cases, SERS microspectroscopy of studied biomolecules using dried Ag colloid/adsorbate systems improves SERS applicability and sensitivity in comparison to measurements directly from Ag colloidal solution.