Fabrication, characterization, and application in surface-enhanced Raman spectrum of assembled type-I collagen-silver nanoparticle multilayered films

Biomedical and ecosafety assessment of marine fish collagen capped silver nanoparticles

In the rapidly evolving landscape of silver nanoparticles (Ag NPs) synthesis, the focus has predominantly been on plant-derived sources, leaving the realm of biological or animal origins relatively uncharted. Breaking new ground, our study introduces a pioneering approach: the creation of Ag NPs using marine fish collagen, termed ClAg NPs, and offers a comprehensive exploration of their diverse attributes. To begin, we meticulously characterized ClAg NPs, revealing their spherical morphology, strong crystalline structure, and average diameter of 5 to 100 nm. These NPs showed potent antibacterial activity, notably against S. aureus (gram-positive), surpassing their efficacy against S. typhi (gram-negative). Additionally, ClAg NPs effectively hindered the growth of MRSA biofilms at 500 μg/mL. Impressively, they demonstrated substantial antioxidant capabilities, out performing standard gallic acid. Although higher concentrations of ClAg NPs induced hemolysis (41.804 %), lower concentrations remained non hemolytic. Further evaluations delved into the safety and potential applications of ClAg NPs. In vitro cytotoxicity studies on HEK 293 and HeLa cells revealed dose-dependent toxicity, with IC50 of 75.28 μg/mL and 79.13 μg/mL, respectively. Furthermore, ClAg NPs affected seed germination, root, and shoot lengths in Mung plants, underscoring their relevance in agriculture. Lastly, zebrafish embryo toxicity assays revealed notable effects, particularly at 500 μg/mL, on embryo morphology and survival rates at 96 hpf. In conclusion, our study pioneers the synthesis and multifaceted evaluation of ClAg NPs, offering promise for their use as versatile nano therapeutics in the medical field and as high-value collagen-based nanobiomaterial with minimal environmental impact.

Synthesis of two-dimensional Ti3C2Tx/Au nanosheets with SERS performance

This study proposes a new method for the preparation of novel MXenes/metal composites with unique chemical properties using reducing agent action. The effect of the reduction reaction time on the preparation conditions of ${{\rm Ti}_3}{{\rm C}_2}{{\rm T}_x}/{\rm Au}$Ti₃C₂T_x/Au nanocomposites is studied, and the contribution of the prepared nanocomposites to the surface Raman reinforcement is analyzed. This study further explores the application of MXene in surface-enhanced Raman spectroscopy.

Self-Assembled Ag-Cu₂O Nanocomposite Films at Air-Liquid Interfaces for Surface-Enhanced Raman Scattering and Electrochemical Detection of H₂O₂

We employ a facile and novel route to synthesize multifunctional Ag-Cu₂O nanocomposite films through the self-assembly of nanoparticles at an air-liquid interface. In the ethanol-water phase, AgNO₃ and Cu(NO₃)₂ were reduced to Ag-Cu₂O nanoparticles by NaBH₄ in the presence of cinnamic acid. The Ag-Cu₂O nanoparticles were immediately trapped at the air-liquid interface to form two-dimensional nanocomposite films after the reduction reaction was finished. The morphology of the nanocomposite films could be controlled by the systematic regulation of experimental parameters. It was found that the prepared nanocomposite films serving as the substrates exhibited strong surface-enhanced Raman scattering (SERS) activity. 4-aminothiophenol (4-ATP) molecules were used as the test probes to examine the SERS sensitivity of the nanocomposite films. Moreover, the nanocomposite films synthesized by our method showed enhanced electrocatalytic activity towards hydrogen peroxide (H₂O₂) and therefore could be utilized to fabricate a non-enzymatic electrochemical H₂O₂ sensor.

The interfacing structural effect of Ag/graphene oxide nanohybrid films on surface enhanced Raman scattering

The interfacing structural effect of Ag/graphene oxide (GO) nanohybrid films on SERS was investigated by using Ag nanostructures immobilized on polyallylamine hydrochloride (PAA) functionalized-GO and reduced GO (RGO) films. We found that the electron transfer from Ag nanostructures to GO derivatives dominantly occurred at the interfaces between Ag nanostructures and the sp² carbon domains of GO and RGO films. By utilizing 4-aminothiophenol (4-ATP) as a Raman probe, it was revealed that this electron transfer process augmented the enhancement factor (EF) of 4-ATP up to ∼1.8 fold on Ag/PAA-RGO nanohybrid films compared to Ag/PAA-GO nanohybrid films with the increasing interfacing area between Ag nanostructures and the sp² carbon domains of GO derivatives through wet-chemical processes.

Intense Raman scattering on hybrid Au/Ag nanoplatforms for the distinction of MMP-9-digested collagen type-I fiber detection

Well-ordered Au-nanorod arrays were fabricated using the focused ion beam method (denoted as fibAu_NR). Au or Ag nanoclusters (NCs) of various sizes and dimensions were then deposited on the fibAu_NR arrays using electron beam deposition to improve the surface-enhanced Raman scattering (SERS) effect, which was verified using a low concentration of crystal violet (10(-)(5)M) as the probe molecule. An enhancement factor of 6.92 × 10(8) was obtained for NCsfibAu_NR, which is attributed to the combination of intra-NC and NR localized surface plasmon resonance. When 4-aminobenzenethiol (4-ABT)-coated Au or Ag nanoparticles (NPs) were attached to NCsfibAu_NR, the small gaps between 4-ABT-coated NPs and intra-NCs allowed detection at the single-molecule level. Hotspots formed at the interfaces of NCs/NRs and NPs/NCs at a high density, producing a strong local electromagnetic effect. Raman spectra from as-prepared type I collagen (Col-I) and Ag-NP-coated Col-I fibers on NCsfibAu_NR were compared to determine the quantity of amino acids in their triple helix structure. Various concentrations of matrix-metalloproteinase-9-digested Col-I fibers on NCsfibAu_NR were qualitatively examined at a Raman laser wavelength of 785nm to determine the changes of amino acids in the Col-I fiber structure. The results can be used to monitor the growth of healing Col-I fibers in a micro-environment.

Using a Macroporous Silver Shell to Coat Sulfonic Acid Group-Functionalized Silica Spheres and Their Applications in Catalysis and Surface-Enhanced Raman Scattering

In this paper, novel organic sulfonic acid group-functionalized silica spheres (SiO2-SO3H) were chosen as a template for fabricating core-shell SiO2-SO3H@Ag composite spheres by the seed-mediated growth method. The SiO2-SO3H spheres could be obtained easily by oxidation of the thiol group-terminated silica spheres (SiO2-SH) with H2O2. Due to the presence of sulfonic acid groups, the [Ag(NH3)2](+) ions were captured on the surface of the silica spheres, followed by in-site reduction to silver nanoseeds for further growth of the silver shell. By this strategy, the complete silver shell could be obtained, and the surface morphologies and structures of the silver shell could be controlled by adjusting the number of sulfonic acid groups on the silica spheres. A large number of sulfonic acid groups on the SiO2-SO3H spheres favored the formation of the macroporous silver shell, which was unique and exhibited good catalytic performance and a high surface-enhanced Raman scattering (SERS) enhancement ability.

Vibrational spectroscopic investigation on interaction of sago starch capped silver nanoparticles with collagen: a comparative physicochemical study using FT-IR and FT-Raman techniques

Vibrational spectroscopies as analytical tools to investigate the interaction of sago starch-capped silver nanoparticles with collagen scaffolds for biomedical applications.

Protein-directed approaches to functional nanomaterials: a case study of lysozyme

Using lysozyme as a model, protein-directed approaches to functional nanomaterials were reviewed, making rational materials design possible in the future.

Functionalizing metal nanostructured film with graphene oxide for ultrasensitive detection of aromatic molecules by surface-enhanced Raman spectroscopy

Surface-enhanced Raman spectroscopy (SERS) as a powerful analytical tool has gained extensive attention. Despite of many efforts in the design of SERS substrates, it remains a grand challenge for creating a general substrate that can detect diverse target analytes. Herein, we report our attempt to address this issue by constructing a novel metal-graphene oxide nanostructured film as SERS substrate. Taking advantages of the high affinity of graphene oxide (GO) toward aromatic molecules and the SERS property of nanostructured metal, this structure exhibits great potential for diverse aromatic molecules sensing, which is demonstrated by using crystal violet (CV) with positive charge, amaranth with negative charge, and neutral phosphorus triphenyl (PPh(3)) as model molecules.

Insulin amyloid superstructures as templates for surface enhanced Raman scattering

Nanostructuring of noble metal surfaces with biomorphic and biological templates facilitates a variety of applications of surface enhanced Raman scattering (SERS). Here we show that the newly reported insulin amyloid superstructures may be employed as stable nanoscaffolds for metallic Au films providing an effective substrate for SERS on covalently bound molecules of 4-mercaptobenzoic acid (4-MBA). The vortex-aligned insulin fibrils are capable of templating nanopatterns in sputtered Au layers without overlapping the SERS spectra of 4-MBA with vibrational bands stemming from the protein. This holds true regardless of whether the incident laser beam is directly backscattered from the 4-MBA layer, or after passage through the insulin amyloid layer.