Layered HfS2 is a promising wide-bandgap semiconductor for next-generation optoelectronic and nanophotonic light-sensitive devices. It exhibits a rich Raman scattering spectrum featuring a dominant A1g mode and several low-intensity modes. At the same time, the Raman intensity of HfS2 is almost indistinguishable when the layer number is low. In this report, surface-enhanced Raman scattering (SERS) of multilayer HfS2 flakes is approached by their decoration with plasmonic silver and gold nanoparticles (NPs) of spherical and nonspherical shapes, which have absorption bands overlapping that of HfS2. Ag nanotriangles (NTs or nanoprisms) support three localized surface plasmon resonance (SPR) modes located at 566, 408 and 333 nm, and Au nanorods (NRs) have two modes located at 920 and 517 nm. Conversely, Ag and Au nanospheres (NSs) own a single SPR mode at 395 and 513 nm. The decoration of HfS2 flakes with Ag NTs, Ag NSs, Au NRs, and Au NSs enables SERS with enhancement factors of 4.9, 1.4, 3.3, and 2.5, respectively. The highest intensity is obtained using nonspherical Ag NTs, whose strong in-plane dipole SPR plasmon mode well fits the wavelength of Raman excitation of 532 nm. Even though the SPR of Au NPs coincides with the excitation wavelength, Au generates somewhat less intense plasmon field compared to that of Ag NPs. Naturally, a stronger light-matter interaction with nonspherical NPs empowers their stronger SPR and SERS due to the generation of plasmonic hot spots at their tips and sharp edges. These results provide fundamental insights into the light-matter coupling in semiconductor/metal-NP plasmonic hybrid systems as well as their SERS application.

Photodynamic therapy (PDT) is a non-invasive anticancer treatment that uses special photosensitizer molecules (PS) to generate singlet oxygen and other reactive oxygen species (ROS) in a tissue under excitation with red or infrared light. Though the method has been known for decades, it has become more popular recently with the development of new efficient organic dyes and LED light sources. Here we introduce a ternary nanocomposite: water-soluble star-like polymer/gold nanoparticles (AuNP)/temoporfin PS, which can be considered as a third-generation PDT system. AuNPs were synthesized in situ inside the polymer molecules, and the latter were then loaded with PS molecules in an aqueous solution. The applied method of synthesis allows precise control of the size and architecture of polymer nanoparticles as well as the concentration of the components. Dynamic light scattering confirmed the formation of isolated particles (120 nm diameter) with AuNPs and PS molecules incorporated inside the polymer shell. Absorption and photoluminescence spectroscopies revealed optimal concentrations of the components that can simultaneously reduce the side effects of dark toxicity and enhance singlet oxygen generation to increase cancer cell mortality. Here, we report on the optical properties of the system and detailed mechanisms of the observed enhancement of the phototherapeutic effect. Combinations of organic dyes with gold nanoparticles allow significant enhancement of the effect of ROS generation due to surface plasmonic resonance in the latter, while the application of a biocompatible star-like polymer vehicle with a dextran core and anionic polyacrylamide arms allows better local integration of the components and targeted delivery of the PS molecules to cancer cells. In this study, we demonstrate, as proof of concept, a successful application of the developed PDT system for in vitro treatment of triple-negative breast cancer cells under irradiation with a low-power LED lamp (660 nm). We consider the developed nanocomposite to be a promising PDT system for application to other types of cancer.

A comparative study of in vitro anti-cancer photodynamic activities of three-component zinc-tetraphenylporphyrin photosensitizer/dextran-graft-polyacrylamide copolymer/Au(Ag) nanoparticle (ZnTPP/D-g-PAA/Au(Ag)NP) nanohybrids on LNCaP prostate cancer cells was carried out under 420 nm light irradiation with low power. A significant cytotoxic effect was revealed for both ZnTPP/D-g-PAA/AgNP and ZnTPP/D-g-PAA/AuNP nanohybrids, where ZnTPP/D-g-PAA/AgNP nanohybrids exhibited considerably higher anticancer activity (82%) compared to ZnTPP/D-g-PAA/AuNP nanohybrids (45%). The higher activity of silver-containing nanohybrids is rationalized based on two factors. The first factor is the resonance of 420 nm light with a absorption Soret peak of the ZnTPP photosensitizer and a localized surface plasmon mode in Ag nanoparticles. Correspondingly, the plasmon enhancement of reactive oxygen species photogeneration by ZnTPP molecules was considerably higher for the nanohybrid containing silver compared to the one containing gold. The second factor is the higher cytotoxicity of Ag nanoparticles compared to Au ones. The study results prove the high potential of D-g-PAA/Ag(Au)NP nanohybrids combined with 420 nm light irradiation with low power in the photodynamic treatment of prostate cancer.

This review elucidates the role of nanotechnology in tackling global health issues, with a particular emphasis on Ukraine’s research efforts in creating nanodrugs for cancer and antimicrobial therapy. Nanomaterials offer promising applications in disease diagnosis, treatment, and prevention, and their properties can be tailored for specific uses via control of nanoparticle size, shape, synthesis conditions, and more. However, the rising incidence of cancer, a leading cause of death worldwide, poses a significant challenge. In Ukraine, cancer rates have seen a substantial increase, fueled by both multifactorial causes and the devastating effects of military aggression. Environmental pollution, including contamination from modern weaponry and the degradation of water and food quality, coupled with chronic stress, exacerbates the risk of cancer. The country’s mortality rate from cancer significantly surpasses that of the EU. Ukrainian studies focused on the development of polymer-based nanodrugs for photodynamic therapy, chemotherapy, and antibacterial hydrogels, highlighting the potential of these nanotechnologies in devising effective cancer prevention and treatment strategies.

Perspective applications of Ag nanoparticles (NPs) stimulate intense research on their affordable synthesis, including green routes. The use of fungi extracts has advantages over other organisms, because of their relatively easy isolation and higher efficiency in a reduction of metal ions and NP formation. Here we report mycosynthesis of AgNPs based on Ganoderma lucidum fruit body extract with different pH values as the bioreducing and stabilising agent. Stable NPs colloids with distinct plasmonic resonance peaking at 408–418 nm are obtained by using photoreduction in a broad pH range (5 to 11). Synthesis efficiency drops only at very acidic conditions, pH = 2.5. The NP size and morphology are studied by dynamic light scattering and scanning electron microscopy. An analysis of FTIR spectra of pure analyte and NP sample indicates that stabilisation of the AgNPs by the components of Ganoderma lucidum extract may take place via forming chemical bonds with the NP surface. These bio-friendly AgNPs are both optically and chemically active, as inferred from surface-enhanced Raman scattering of a standard dye analytes and charge transfer-induced quenching of the photoluminescence of both dye and inorganic NPs, and can be studied for various applications which require direct access to the AgNP surface.

Introduction:Cancer chemotherapy faces two major challenges - high toxicity of active substances and tumor resistance to drugs. Low toxic nanocarriers in combination with anticancer agents can significantly increase the effectiveness of therapy. Modern advances in nanotechnology make it easy to create materials with the necessary physical and chemical properties.Methods:Two hybrid nanosystems of dextran-polyacrylamide/ zinc oxide nanoparticles (D-PAA/ZnO NPs) were synthesized in aqueous solution with zinc sulphate (D-PAA/ZnO NPs (SO42-)) and zinc acetate (D-PAA/ZnO NPs (-OAc)). The light absorption, fluorescence, dynamic light scattering and transmission electron microscopy for nanocomposite characterization were used. MTT, neutral red uptake and scratch assays were selected as fibroblasts cytotoxicity assays. Cytotoxicity was tested in vitro for normal fibroblasts, MAEC, prostate (LNCaP, PC-3, DU-145) and breast (MDA-MB-231, MCF-7) cancer cells lines. Immunocytochemical methods were used for detection of Ki-67, p53, Bcl-2, Bax, e-cadherin, N-cadherin and CD44 expression. Acridine orange was used to detect morphological changes in cells.Results:The radius of ZnO NPs (SO42-) was 1.5 nm and ZnO NPs (-OAc) was 2 nm. The nanosystems were low-toxic to fibroblasts, MAEC. Cells in the last stages of apoptosis with the formation of apoptotic bodies were detected for all investigated cancer cell lines. Proapoptotic proteins expression in cancer cells indicates an apoptotic death. Increased expression of E-cadherin and N-cadherin was registered for cancer cells line LNCaP, PC-3, DU-145 and MCF-7 after 48 h incubation with D-PAA/ZnO NPs (SO42-).Conclusion:The nanosystems were low-toxic to fibroblasts, MAEC. The D-PAA/ZnO NPs nanosystem synthesized using zinc sulphate demonstrates high cytotoxicity due to destruction of various types of cancer cells in vitro and potentially increases adhesion between cells. Thus, our findings indicate the selective cytotoxicity of D-PAA/ZnO NPs against cancer cells and can be potentially used for cancer treatment.

The parameters of the shell and interface in semiconductor core/shell nanocrystals (NCs) are determinant for their optical properties and charge transfer but are challenging to be studied. Raman spectroscopy was shown earlier to be a suitable informative probe of the core/shell structure. Here, we report the results of a spectroscopic study of CdTe NCs synthesized by a facile route in water, using thioglycolic acid (TGA) as a stabilizer. Both core-level X-ray photoelectron (XPS) and vibrational (Raman and infrared) spectra show that using thiol during the synthesis results in the formation of a CdS shell around the CdTe core NCs. Even though the spectral positions of the optical absorption and photoluminescence bands of such NCs are determined by the CdTe core, the far-infrared absorption and resonant Raman scattering spectra are dominated by the vibrations related with the shell. The physical mechanism of the observed effect is discussed and opposed to the results reported before for thiol-free CdTe Ns as well as CdSe/CdS and CdSe/ZnS core/shell NC systems, where the core phonons were clearly detected under similar experimental conditions.

Plasmonic cavity metasurfaces based on metal laser-induced periodic surface structures (LIPSSs) and non-spherical metal nanoparticles (NPs) were shown to provide the highly sensitive detection and imaging of biomolecules at room temperature without their special labelling. We studied the enhancement of Raman scattering of 5’-deoxyadenosine monophosphate (dAMP) deposited on two types of fabricated cavity metasurfaces: 1) Ag LIPSSs and Ag triangular nanoprisms, 2) crystalline Si LIPSSs and a pre-deposited thin gold film modified during laser treatment. Both types of the metasurfaces contain metal or metal-semiconductor substrates processed with femtosecond laser radiation in a single step. An enhancement of more than 100 times for some Raman peaks of dAMP at Ag nanoprisms/Ag LIPSSs was achieved. In the case of Au NPs/Si LIPSS metasurface a slight increase of Raman spectrum of dAMP was revealed. This effect additionally emphasizes the crucial role of the near-field coupling of the localized surface plasmon modes of Ag nanoprisms and the propagating surface plasmon polaritons of Ag surfaces and consequent formation of collective plasmonic gap modes of the entire plasmonic cavity that determine the appearance of hot spots at such metasurfaces.

Colloidal silver nanoparticles (NPs) synthesized using fungi extract (Ganoderma lucidum) as a reducing and stabilizing agent are studied as a “substrate” for enhancement of Raman scattering (SERS) of analyte molecules. The NPs obtained are nearly spherical with a mean size of 20–30 nm, as proved by scanning electron microscopy (SEM) and dynamic light scattering (DLS). Close values of the hydrodynamic NPs size derived from DLS and the size of a bare silver part of the NP seen in SEM indicate that the passivating layer formed on the NP surface is only a few nm thick, making these NPs suitable for various applications involving both plasmonic enhancement and charge or energy transfer phenomena. The capability of plasmonic coupling is confirmed by a good SERS efficiency demonstrated for standard dye analytes (Rhodamine 6G, R6G, and crystal violet, CV). The charge transfer capability is proved by quenching of the R6G and CV fluorescence. In addition to the dependence of the SERS efficiency on the AgNP synthesis conditions, we discuss spectral effects that can be related to the adsorption geometry of the analyte molecule in a solution and a dried film. A comparable SERS efficiency being obtained for AgNPs synthesized in a broad range of pH values (5 to 11) enables a broad range of the molecules and processes, to which the obtained NPs can be applied.

Polyacrylamide-based hydrogels were loaded with cephalosporin antibiotics to obtain antimicrobial wound and burn dressings. At the stage of synthesis, small additives of dextrans of different molecular weights were used to affect the internal structure of the final polyacrylamide-based hydrogels. The control of antibiotic content, as well as its release into an aqueous solution, was performed using the HPLC–UV method. Antibacterial activity of the antibiotic-loaded hydrogels was tested in vitro on wild strains of Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae. Compared to polyacrylamide hydrogels, dextran-graft-polyacrylamide hydrogels containing the same antibiotics demonstrated some differences in the antimicrobial activity that should be considered when creating an antimicrobial hydrogel formulation. Successful use of the synthesized antimicrobial hydrogels was shown in vivo in a rat model.

The thermoresponsive Zinc TetraPhenylPorphyrin photosensitizer/Dextran poly (N-isopropylacrylamide) graft copolymer/Au Nanoparticles (ZnTPP/D-g-PNIPAM/AuNPs) triple hybrid nanosystem was synthesized in aqueous solution as a nanodrug for potential use in thermally driven and controlled photodynamic therapy applications. The aqueous solution of the nanosystem has demonstrated excellent stability in terms of aggregation and sedimentation several days after preparation. Optimal concentrations of the components of hybrid nanosystem providing the lowest level of aggregation and the highest plasmonic enhancement of electronic processes in the photosensitizer molecules have been determined. It has been revealed that the shrinking of D-g-PNIPAM macromolecule during a thermally induced phase transition leads to the release of both ZnTPP molecules and Au NPs from the ZnTPP/D-g-PNIPAM/AuNPs macromolecule and the strengthening of plasmonic enhancement of the electronic processes in ZnTPP molecules bound with the polymer macromolecule. The 2.7-fold enhancement of singlet oxygen photogeneration under resonant with surface plasmon resonance has been observed for ZnTPP/D-g-PNIPAM/AuNPs proving the plasmon nature of such effect. The data obtained in vitro on wild strains of Staphylococcus aureus have proved the high potential of such nanosystem for rapid photodynamic inactivation of microorganisms particular in wounds or ulcers on the body surface.

Two-dimensional (2D) MoS2 is emerging as a promising candidate for novel optoelectronics and flexible devices, but the photoluminescence (PL) efficiency is still limited for actual photonic applications. Plasmonic enhancement is the best way to increase the PL emission of 2D materials. In this study, the PL enhancement of 2D MoS2 decorated with Au nanorods (NRs) and nanospheres (NSs) at room temperature is investigated, focusing in particular on the effect of the nonspherical shape of NRs. To have a proper comparison, both nanoparticles have very similar diameters of 13-14 nm, while the NR average length is 81 nm. After decorating with Au NRs and NSs, the average PL enhancement of few-layer MoS2 is about 4.3 and 2 times, respectively. The Raman spectra are similarly enhanced, 3.8 and 2.4 times (A(1g) mode), respectively. The maximal enhancement is observed for the samples with Au NRs: this feature can be related to highly localized plasmonic hot spots in vicinity of the NR tips. A strong electric field within the hot spots causes the generation of additional free electron-hole pairs and, in turn, the enhancement of exciton excitation and the increase of the PL intensity. Simultaneously, the injection of hot electrons from the metal increases the probability of trions generation, thus contributing to the PL enhancement.

A triple thermosensitive polymer Dextran-g-Poly(N-isopropylacrylamide)/Au nanoparticles/Perylenediimide (D-g-PNIPAM/AuNPs/PDI) hybrid nanosystem was formulated in aqueous solution for potential use as thermores-ponsive fluorescent optical switch and label. The completely reversible effect of sharp enhancement-quenching of the photoluminescence of D-g-PNIPAM/AuNPs/PDI nanosystem was revealed during the heating-cooling cycle in the narrow temperature range of 25-47 ?C, containing the temperature point of the LCST phase transition of the thermosensitive polymer. The sharp change in the intensity of photoluminescence was shown to result from the competing effects of plasmonic enhancement and non-radiative FRET transfer of electronic excitation energy during thermo-induced LCST transition of the D-g-PNIPAM macromolecule. The observed effect allows to carry out the temperature control of the photoluminescence intensity, which appears to be particularly important for potential applications of D-g-PNIPAM/AuNPs/PDI hybrid nanosystem in photonics, biology and medicine, such as thermosensitive fluorescent optical switch and label or intracellular fluorescent thermometer.

The aim of the present research was to assess the cytotoxicity of gold and silver nanoparticles synthesized into dextran-graft-polyacrylamide (D-PAA) polymer nanocarrier, which were used as a basis for further preparation of multicomponent nanocomposites revealed high efficacy for antitumor therapy. The evaluation of the influence of Me-polymer systems on the viability and metabolic activity of fibroblasts and eryptosis elucidating the mechanisms of the proeryptotic effects has been done in the current research. The nanocomposites investigated in this study did not reduce the survival of fibroblasts even at the highest used concentration. Our findings suggest that hybrid Ag/D-PAA composite activated eryptosis via ROS- and Ca2+-mediated pathways at the low concentration, in contrast to other studied materials. Thus, the cytotoxicity of Ag/D-PAA composite against erythrocytes was more pronounced compared with D-PAA and hybrid Au/polymer composite. Eryptosis is a more sensitive tool for assessing the biocompatibility of nanomaterials compared with fibroblast viability assays.

We report a new pathway for the synthesis of plasmonic gold nanoparticles (Au NPs) in a bio-compatible medium. A modified room temperature approach based on the standard Turkevich synthesis, using sodium citrate as a reducing and stabilizing agent, results in a highly stable colloidal suspension of Au NPs in dimethyl sulfoxide (DMSO). The mean NP size of about 15 nm with a fairly low size distribution is revealed by scanning electron microscopy. The stability test through UV-vis absorption spectroscopy indicates no sign of aggregation for months. The Au NPs are also characterized by X-ray photoelectron, Raman scattering, and FTIR spectroscopies. The stabilisation mechanism of the Au NPs in DMSO is concluded to be similar to that of NPs synthesized in water. The Au NPs obtained in this work are applicable as SERS substrates, as proved by common analytes. In terms of bio-applications, they do not possess such side-effects as pronounced antibacterial activity, based on the tests performed on non-pathogenic Gram-positive or Gram-negative bacteria.

Plasmonic metasurfaces with coupled gap and collective surface plasmon polariton modes are of interest for a variety of optoelectronic devices. The coupling between the gap and plasmon polariton modes leads to tunable extinction spectra that provide flexibility when used in various photonic applications. We demonstrate both experimentally and numerically the polarization and angle dependent tunable optical extinction spectra of a gold nanoparticles monolayer on a glass substrate in close proximity to a thin aluminum film. The monolayer of gold nanoparticles is separated from the aluminum thin film by a dielectric shellac spacer. We observe three angle and polarization dependent peaks in the extinction spectra when the shellac spacer is 10 nm. The three peaks degenerate into one hybrid mode when the spacer thickness is 30 nm. By using a finite-difference-time-domain (FDTD) numerical method, we confirm the position of both the collective surface plasmon and the gap modes. Changing the polarization of the incident light leads to a change of the width and a shift of the wavelength of the peaks.

The temperature-driven plasmon-exciton coupling in thermoresponsive dextran-graft-PNIPAM/Au nanoparticle/CdTe quantum dot (D-g-PNIPAM/Au NPs/CdTe QDs) hybrid nanosystem was studied. A significant (0.84 eV) splitting of the absorption peak was observed in the absorption spectrum of the nanosystem, which reflects the fact of formation of plexcitons, occurring due to strong plasmon-exciton coupling. An increasing with time plasmonic enhancement of the photoluminescence of CdTe QDs was revealed, as a result of the penetration of quantum dots into the volume of the D-g-PNIPAM/Au NP hybrid nanosystem and bonding to it. The heating–cooling cycle of the aqueous solution of the studied nanosystem leads to a reversible quenching-recovery alteration of the QD photoluminescence. The quenching was rationalized as a result of an increased probability of nonradiative resonance energy transfer (RET) from CdTe QDs to Au NPs, which occurs due to shortening of the NP-QD distance, caused by shrinking of the macromolecule due to cooling-induced lower critical solution temperature phase transition. Increasing the NP-QD distance in the heating stage recovers the QD PL intensity. The observed effect opens up opportunities for the controlled reversible temperature-driven tuning of the photoluminescence intensity of D-g-PNIPAM/Au NP/CdTe QD nanosystem, which is highly important for its potential use in photonics and biomedical applications.

The effects of the temperature on the surface plasmon resonance (SPR) in noble metal nanoparticles at various temperatures ranging from 77 to 1190 K are reviewed. A temperature increase results in an appreciable red shift and leads to a broadening of the SPR in the nanoparticles (NPs). This observed thermal expansion along with an increase in the electron-phonon scattering rate with rising temperature emerge as the dominant physical mechanisms producing the red shift and broadening of the SPR. Strong temperature dependence of surface plasmon enhanced photoluminescence from silver (Ag) and copper (Cu) NPs is observed. The quantum photoluminescence yield of Ag nanoparticles decreases as the temperature increases, due to a decrease in the plasmon enhancement resulting from an increase in the electron-phonon scattering rate. An anomalous temperature dependence of the photoluminescence from Cu nanoparticles was also observed; the quantum yield of photoluminescence increases with the temperature. The interplay between the SPR and the interband transitions plays a critical role in this effect. The surface-plasmon involved laser heating of a dense 2D layer of gold (Au) NPs and of Au NPs in water colloids is also examined. A strong increase in the Au NP temperature occurs, when the laser frequency approaches the SPR. This finding supports the resonant plasmonic character of the laser heating of metal NPs. The sharp blue shift of the surface plasmon resonance in colloidal Au NPs at temperatures exceeding the water boiling point indicates the vapor-bubble formation near the surface of the NPs.

A zinc tetraphenylporphyrin photosensitizer/dextran graft polyacrylamide anionic copolymer/Au nanoparticles (ZnTPP/D-g-PAAan/AuNPs) triple hybrid nanosystem was synthesized in water-based solution as a nanodrug for potential photodynamic therapy applications. Dynamic light scattering studies showed that the nanosystem is stable against aggregation and sedimentation for several days after preparation. The dependence of the ZnTPP fluorescence intensity on the gold concentration in the ZnTPP/D-g-PAAan/AuNPs nanosystem has been revealed to be non-monotonic, with a maximum 2.5-fold enhancement at a concentration of 0.008 g L-1. The non-monotonic dependence was explained to be caused by two competing processes, namely plasmonic enhancement and FRET, indicating the existence of an optimal concentration of Au NPs that can provide the highest plasmonic enhancement of the electronic processes involving the ZnTPP photosensitizer. A 2.6-fold enhancement of singlet oxygen photogeneration under excitation resonant with the localized surface plasmon resonance of the Au NPs has been detected for ZnTPP/D-g-PAAan/AuNPs, proving the plasmonic origin of this phenomenon. The high bactericidal efficiency of ZnTPP/D-g-PAAan/AuNPs water-based solution under 420 nm and 530 nm light irradiation was revealed against wild strains of Staphylococcus aureus. Therefore, the ZnTPP/D-g-PAAan/AuNPs nanosystem can potentially be used in photodynamic therapy for the prevention and treatment of the bacterial contamination of open wounds.

Cu2ZnSnS4 (CZTS) thin films deposited using direct current magnetron sputtering and sulfurized at argon atmosphere pressures of 950, 460, and 50 mbar are studied in a view of solar cell absorber fabrication. The main novelty in the work is the influence of the radio frequency (RF) electromagnetic field treatment on the Cu2−xS secondary phase. The treatment reduces the amount of the Cu2−xS secondary phase, which is confirmed by Raman spectroscopy. The RF effect is long-term, at least one year later. So, this treatment is a promising technique to achieve higher purities of CZTS absorber layers for solar cells.