Surface Plasmon Resonance or Biocompatibility-Key Properties for Determining the Applicability of Noble Metal Nanoparticles

Precision in cancer diagnostics: ultra-sensitive detection of MCF-7 breast cancer cells by gold nanostructure-enhanced electrochemical biosensing

Timely identification of cancers is pivotal in optimizing treatment efficacy and reducing their widespread impact. This study introduces a novel biosensor for the sensitive electrochemical detection of cancer cells overexpressing mucin 1 (MUC1), a well-established model for breast cancer. The sensor substrate comprises gold columnar nanostructures obtained through glancing angle deposition (GLAD) of copper nanostructures, subsequently replaced by gold via a facile galvanic replacement process. Functionalizing these gold nanostructures with aptamers targeting the MUC1 glycoproteins, a prominent cancer biomarker, enables specific recognition of MCF-7 breast cancer cells. The proposed electrochemical sensing platform offers several advantages, including high selectivity, a wide linear range of detection, a low detection limit of 30 cells per mL, and long-term stability, rendering this sensor highly desirable for definitive breast cancer diagnosis.

Fabrication of an Au-doped Cu/Fe oxide-polymer core-shell nanoreactor with chemodynamic and photodynamic dual effects as potential cancer therapeutic agents

Nanoparticles are widely used in biomedical applications and cancer treatments due to their minute scale, multi-function, and long retention time. Among the various nanoparticles, the unique optical property derived from the localized surface plasmon resonance effect of metallic nanoparticles is a primary reason that metallic nanoparticles are researched and applied. Copper and Iron nanoparticles have the potential to generate hydroxyl radicals in excess H₂O₂ via Fenton or Fenton-like reactions. On the other hand, gold nanoparticles equipped with a photosensitizer can transfer the energy of photons to chemical energy and enhance the production of singlet oxygen, which is suitable for cancer treatment. With the actions of these two reactive oxygen species in the tumor microenvironment, cell apoptosis can further be induced. In this work, we first synthesized dual metal nanoparticles with poly[styrene-alt-(maleic acid, sodium salt)(Cu ferrite oxide-polymer) by a simple one-step hydrothermal reduction reaction. Then, gold(III) was reduced and doped into the structure, which formed a triple metal structure, Au-doped Cu ferrite nanoparticles (Au/Cu ferrite oxide-polymer NPs). The metal ratio of the product could be controlled by manipulating the Fe/Cu ratio of reactants and the sequence of addition of reactants. The core-shell structure was verified by transmission electron microscopy. Moreover, the hydroxyl radical and singlet oxygen generation ability of Au/Cu ferrite oxide-polymer was proved. The chemodynamic and photodynamic effect was measured, and the in vitro ROS generation was observed. Furthermore, the behavior of endocytosis by cancer cells could be controlled by the magnetic field. The result indicated that Au/Cu ferrite oxide-polymer core-shell nanoreactor is a potential agent for chemodynamic/photodynamic synergetic therapy.

Bismuth Oxychloride Nanomaterials Fighting for Human Health: From Photodegradation to Biomedical Applications

Environmental pollution and various diseases seriously affect the health of human beings. Photocatalytic nanomaterials (NMs) have been used for degrading pollution for a long time. However, the biomedical applications of photocatalytic NMs have only recently been investigated. As a typical photocatalytic NM, bismuth oxychloride (BiOCl) exhibits excellent photocatalytic performance due to its unique layered structure, electronic properties, optical properties, good photocatalytic activity, and stability. Some environmental pollutants, such as volatile organic compounds, antibiotics and their derivatives, heavy metal ions, pesticides, and microorganisms, could not only be detected but also be degraded by BiOCl-based NMs due to their excellent photocatalytic and photoelectrochemical properties. In particular, BiOCl-based NMs have been used as theranostic platforms because of their CT and photoacoustic imaging abilities, as well as photodynamic and photothermal performances. However, some reviews have only profiled the applications of dye degradation, hydrogen or oxygen production, carbon dioxide reduction, or nitrogen fixation of BiOCl NMs. There is a notable knowledge gap regarding the systematic study of the relationship between BiOCl NMs and human health, especially the biomedical applications of BiOCl-based NMs. As a result, in this review, the recent progress of BiOCl-based photocatalytic degradation and biomedical applications are summarized, and the improvement of BiOCl-based NMs in environmental and healthcare fields are also discussed. Finally, a few insights into the current status and future perspectives of BiOCl-based NMs are given.

Generalized figure of merit for plasmonic dip measurement-based surface plasmon resonance sensors

We propose a theoretical framework to analyze quantitative sensing performance parameters, including sensitivity, full width at half maximum, plasmonic dip position, and figure of merits for different surface plasmon operating conditions for a Kretschmann configuration. Several definitions and expressions of the figure of merit have been reported in the literature. Moreover, the optimal operating conditions for each figure of merit are, in fact, different. In addition, there is still no direct figure of merit comparison between different expressions and definitions to identify which definition provides a more accurate performance prediction. Here shot-noise model and Monte Carlo simulation mimicking the noise behavior in SPR experiments have been applied to quantify standard deviation in the SPR plasmonic dip measurements to evaluate the performance responses of the figure of merits. Here, we propose and formulate a generalized figure of merit definition providing a good performance estimation to the detection limit. The measurement parameters employed in the figure of merit formulation are identified by principal component analysis and machine learning. We also show that the proposed figure of merit can provide a good estimation for the surface plasmon resonance performance of plasmonic materials, including gold and aluminum, with no need for a resource-demanding computation.

Bioactive Properties of Composites Based on Silicate Glasses and Different Silver and Gold Structures

Using an ideal biomaterial to treat injured bones can accelerate the healing process and simultaneously exhibit antibacterial properties; thus protecting the patient from bacterial infections. Therefore, the aim of this work was to synthesize composites containing silicate-based bioactive glasses and different types of noble metal structures (i.e., AgI pyramids, AgIAu composites, Au nanocages, Au nanocages with added AgI). Bioactive glass was used as an osteoconductive bone substitute and Ag was used for its antibacterial character, while Au was included to accelerate the formation of new bone. To investigate the synergistic effects in these composites, two syntheses were carried out in two ways: AgIAu composites were added in either one step or AgI pyramids and Au nanocages were added separately. All composites showed good in vitro bioactivity. Transformation of AgI in bioactive glasses into Ag nanoparticles and other silver species resulted in good antibacterial behavior. It was observed that the Ag nanoparticles remained in the Au nanocages, which was also beneficial in terms of antibacterial properties. The presence of Au nanoparticles contributed to the composites achieving high cell viability. The most outstanding result was obtained by the consecutive addition of noble metals into the bioactive glasses, resulting in both a high antibacterial effect and good cell viability.

Dual Sensitization via Electron and Energy Harvesting in a Nanohybrid for Improvement of Therapeutic Efficacy

We demonstrate experimental evidence of the effect of surface plasmon resonance of noble metal nanoparticles (NPs) on the activity of a well-known biomedicinal drug in the proximity of a semiconductor having a wide band gap for enhanced photodynamic therapy (PDT) efficacy. We have chosen riboflavin (Rf) (or vitamin B₂) as a model photosensitizer, attached with ZnO NPs and further attached with gold (Au) NP-decorated ZnO to increase the efficiency. The synthesized nanohybrids are characterized with the help of different microscopic, optical spectroscopic, and density functional theory (DFT)-based techniques. The DFT and time-dependent DFT-based calculations validate the experimental findings. A detailed ultrafast spectroscopic study has been carried out further to study the excited-state charge dynamics in the interface of the nanohybrids. The occurrence of a Förster resonance energy transfer (FRET) between Rf and Au has been found to be the key reason for the increased efficiency in the Rf-ZnO-Au nanohybrid over the Rf-ZnO one. The dipolar coupling between Au and Rf in the Rf-ZnO-Au nanohybrid further facilitates the generation of reactive oxygen species (ROS) in comparison to Rf-ZnO under blue-light irradiation. The greater efficiency in ROS generation by the Rf-ZnO-Au nanohybrid has been utilized for antimicrobial action against methicillin-resistant S. aureus (MRSA). Overall, the present study highlights the dual sensitization for achieving enhanced electron injection efficiency in the Rf-ZnO-Au nanohybrid in order to use it as an antibacterial agent that could be translated in PDT.

Noble Metal Nanomaterial-Based Biosensors for Electrochemical and Optical Detection of Viruses Causing Respiratory Illnesses

Noble metal nanomaterials, such as gold, silver, and platinum, have been studied extensively in broad scientific fields because of their unique properties, including superior conductivity, plasmonic property, and biocompatibility. Due to their unique properties, researchers have used them to fabricate biosensors. Recently, biosensors for detecting respiratory illness-inducing viruses have gained attention after the global outbreak of coronavirus disease (COVID-19). In this mini-review, we discuss noble metal nanomaterials and associated biosensors for detecting respiratory illness-causing viruses, including SARS-CoV-2, using electrochemical and optical detection techniques. this review will provide interdisciplinary knowledge about the application of noble metal nanomaterials to the biomedical field.

Surface Chemistry, Crystal Structure, Size and Topography Role in the Albumin Adsorption Process on TiO2 Anatase Crystallographic Faces and Its 3D-Nanocrystal: A Molecular Dynamics Study

TiO2 is widely used in biomaterial implants. The topography, chemical and structural properties of titania surfaces are an important aspect to study. The size of TiO2 nanoparticles synthetized by sol–gel method can influence the responses in the biological environment, and by using appropriate heat treatments different contents of different polymorphs can be formed. Protein adsorption is a crucial step for the biological responses, involving, in particular, albumin, the most abundant blood protein. In this theoretical work, using molecular mechanics and molecular dynamics methods, the adsorption process of an albumin subdomain is reported both onto specific different crystallographic faces of TiO2 anatase and also on its ideal three-dimensional nanosized crystal, using the simulation protocol proposed in my previous theoretical studies about the adsorption process on hydrophobic ordered graphene-like or hydrophilic amorphous polymeric surfaces. The different surface chemistry of anatase crystalline faces and the nanocrystal topography influence the adsorption process, in particular the interaction strength and protein fragment conformation, then its biological activity. This theoretical study can be a useful tool to better understand how the surface chemistry, crystal structure, size and topography play a key role in protein adsorption process onto anatase surface so widely used as biomaterial.

COVID-19 Pandemic: What about the Safety of Anti-Coronavirus Nanoparticles?

Every day, new information is presented with respect to how to best combat the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This manuscript sheds light on such recent findings, including new co-factors (i.e., neuropilin-1) and routes (i.e., olfactory transmucosal) allowing cell entry of SARS-CoV-2 and induction of neurological symptoms, as well as the new SARS-CoV-2 variants. We highlight the SARS-CoV-2 human-animal interfaces and elaborate containment strategies using the same vaccination (i.e., nanoparticle "NP" formulations of the BNT162b2 and mRNA-1273 vaccines) for humans, minks, raccoon dogs, cats, and zoo animals. We investigate the toxicity issues of anti-CoV NPs (i.e., plasmonic NPs and quantum dots) on different levels. Namely, nano-bio interfaces (i.e., protein corona), in vitro (i.e., lung cells) and in vivo (i.e., zebrafish embryos) assessments, and impacts on humans are discussed in a narrative supported by original figures. Ultimately, we express our skeptical opinion on the comprehensive administration of such antiviral nanotheranostics, even when integrated into facemasks, because of their reported toxicities and the different NP parameters (e.g., size, shape, surface charge, and purity and chemical composition of NPs) that govern their end toxicity. We believe that more toxicity studies should be performed and be presented, clarifying the odds of the safe administration of nanotoxocological solutions and the relief of a worried public.

Bioactive glass-biopolymers‑gold nanoparticle based composites for tissue engineering applications

Biomaterials based on bioactive glass with gold nanoparticle composites have many applications in tissue engineering due to their tissue regeneration and angiogenesis capacities. The objectives of the study were to develop new composites using bioactive glass with gold nanospheres (BGAuSP) and gold nanocages (BGAuIND), individually introduced in alginate-pullulan (Alg-Pll) polymer, to evaluate their biocompatibility potential, and to compare the obtained results with those achieved when β-tricalcium phosphate-hydroxyapatite (βTCP/HA) replaced the BG. The novel composites underwent structural and morphological characterization followed by in vitro viability testing on fibroblast and osteoblast cell lines. Additionally, the biomaterials were subcutaneously implanted in Sprague Dawley rats, for in vivo biocompatibility assessment during 3 separate time frames (14, 30 and 60 days). The biological effects were evaluated by histopathology and immunohistochemistry. The physical characterization revealed the cross-linking between polymers and glasses/ceramics and demonstrated a suitable thermal stability for sterilization processes. The in vitro assays demonstrated adequate form, pore size of composites ranging from few micrometers up to 100 μm, while the self-assembled apatite layer formed after simulated body fluid immersion confirmed the composites' bioactivity. Viability assays have highlighted optimal cellular proliferation and in vitro biocompatibility for all tested composites. Furthermore, based on the in vivo subcutaneous analyses the polymer composites with BGAuNP have shown excellent biocompatibility at 14, 30 and 60 days, exhibiting marked angiogenesis while, tissue proliferation was confirmed by high number of Vimentin positive cells, in comparison with the polymer composite that contains βTCP/HA, which induced an inflammatory response represented by a foreign body reaction. The obtained results suggest promising, innovative, and biocompatible composites with bioactive properties for future soft tissue and bone engineering endeavours.

Fabrication of Anisotropic Cu Ferrite-Polymer Core-Shell Nanoparticles for Photodynamic Ablation of Cervical Cancer Cells

In this work we developed methylene blue-immobilized copper-iron nanoparticles (MB-CuFe NPs) through a facile one-step hydrothermal reaction to achieve a better phototherapeutic effect. The Fe/Cu ratio of the CuFe NPs was controllable by merely changing the loading amount of iron precursor concentration. The CuFe NPs could serve as a Fenton catalyst to convert hydrogen peroxide (H2O2) into reactive oxygen species (ROS), while the superparamagnetic properties also suggest magnetic resonance imaging (MRI) potential. Furthermore, the Food and Drug Administration (FDA)-approved MB photosensitizer could strongly adsorb onto the surface of CuFe NPs to facilitate the drug delivery into cells and improve the photodynamic therapy at 660 nm via significant generation of singlet oxygen species, leading to enhanced cancer cell-damaging efficacy. An MTT (thiazolyl blue tetrazolium bromide) assay proved the low cytotoxicity of the CuFe NPs to cervical cancer cells (HeLa cells), namely above 80% at 25 ppm of the sample dose. A slight dissolution of Cu and Fe ions from the CuFe NPs in an acidic environment was obtained, providing direct evidence for CuFe NPs being degradable without the risk of long-term retention in the body. Moreover, the tremendous photo-to-thermal conversion of CuFe NPs was examined, which might be combined with photodynamic therapy (PDT) for promising development in the depletion of cancer cells after a single pulse of deep-red light irradiation at high laser power.

Phyto-nano-hybrids of Ag-CuO particles for antibacterial activity against drug-resistant pathogens

Background

The present study reports the antibacterial potential of phyto-nano-hybrid particles Ag-CuO (silver-copper oxide) against drug-resistant pathogens isolated from a Russian hospital in Krasnoyarsk, Siberia. The synthesis of nano-hybrid was achieved by phytogenic source by using leaves of Murraya koenigii. The nano-hybrid particles were well characterized using hyphenated techniques and results of the antibacterial assay was tabulated.

Results

The UV-visible spectra displayed absorption at 420 nm with the shoulder peak at 355 nm indicating the hybridization. The FTIR analysis revealed the presence of phenol, amine, methyl, carbohydrate and aromatic as major functional groups. The XRD analysis revealed the presence of Bragg’s intensities at 2 theta angle depicting the crystalline nature of Ag-CuO nano-hybrid. The TEM analysis displayed the polydispered properties of Ag-CuO nano-hybrid with the size in the range of 60–80 nm exhibiting different shapes ranging from spherical, rod and oval. The antibacterial activity of Ag-CuO nano-hybrid was tested against multidrug-resistant pathogens that resulted in highest activity against P. aeruginosa strain with an inhibition zone of 14 mm in diameter. The MIC concentrations ranged from 0.3125 to 2.5 μg/ml and broth dilution assay displayed dose-dependent properties of Ag-CuO nano-hybrid particles.

Conclusion

The obtained results are interesting to report the preliminary insight to develop biocompatible hybrid particles to combat drug-resistant pathogens. The developed nano-hybrid particles displayed activity against all the test pathogens investigated against both Gram-positive and Gram-negative bacteria. Thus, the study forms preliminary investigation to report nano-hybrid particles as broad spectrum antibacterial agents.

Nanoparticle-hydrogel superstructures for biomedical applications

The incorporation of nanoparticles into hydrogels yields novel superstructures that have become increasingly popular in biomedical research. Each component of these nanoparticle-hydrogel superstructures can be easily modified, resulting in platforms that are highly tunable and inherently multifunctional. The advantages of the nanoparticle and hydrogel constituents can be synergistically combined, enabling these superstructures to excel in scenarios where employing each component separately may have suboptimal outcomes. In this review, the synthesis and fabrication of different nanoparticle-hydrogel superstructures are discussed, followed by an overview of their use in a range of applications, including drug delivery, detoxification, immune modulation, and tissue engineering. Overall, these platforms hold significant clinical potential, and it is envisioned that future development along these lines will lead to unique solutions for addressing areas of pressing medical need.

Hydrothermal Galvanic-Replacement-Tethered Synthesis of Ir-Ag-IrO2 Nanoplates for Computed Tomography-Guided Multiwavelength Potent Thermodynamic Cancer Therapy

Beyond the synthesis of typical nanocrystals, various breakthrough approaches have been developed to provide more useful structural features and functionalities. Among them, galvanic replacement, a structural transformation reaction accompanied by constituent element substitution, has been applied to various areas. However, the innovative improvement for galvanic replacement needs to be considered because of the limitation of applicable element pairs to maintain structural stability. To expand the boundary of galvanic-replacement-mediated synthesis, we have become interested in the Group 9 metallic element Ir, which is considered a fascinating element in the field of catalysis, but whose size and shape regulation has been conventionally regarded as difficult. To overcome the current limitations, we developed a hydrothermal galvanic-replacement-tethered synthetic route to prepare Ir-Ag-IrO₂ nanoplates (IrNPs) with a transverse length of tens of nanometers and a rough surface morphology. A very interesting photoreactivity was observed from the prepared IrNPs, with Ag and IrO₂ coexisting partially, which showed photothermal conversion and photocatalytic activity at different ratios against extinction wavelengths of 473, 660, and 808 nm. The present IrNP platform showed excellent photothermal conversion efficiency under near-infrared laser irradiation at 808 nm and also represented an effective cancer treatment in vitro and in vivo through a synergistic effect with reactive oxygen species (ROS) generation. In addition, computed tomography (CT) imaging contrast effects from Ir and IrO₂ composition were also clearly observed.

Skin wound regeneration with bioactive glass-gold nanoparticles ointment

The bioactive glasses can lead to the promotion of growth of granulation tissue, while the gold nanoparticles (AuNPs) can induce the acceleration of wound healing including tissue regeneration, connective tissue formation, and angiogenesis. The aim of this study was to evaluate the impact of using the bioactive glass (BG) and BG-AuNPs composites on skin wound healing in experimental rat models for 14 days. Sol-gel derived BGs and BG-AuNPs composites mixed with Vaseline at 6, 12 and 18 wt% were used to evaluate the repair response of the skin. During the process of healing, granulomatous reaction was observed in the wound treated with 12 and 18 wt% BG-Vaseline ointments. Furthermore, a strong vascular proliferation and complete wound regeneration were found in 18%BG-AuNPs-Vaseline treated groups. The results derived from the performed investigations revealed that the 18% BG-AuNPs-Vaseline ointment is a promising candidate for wound healing applications.

Recent insights in magnetic hyperthermia: From the "hot-spot" effect for local delivery to combined magneto-photo-thermia using magneto-plasmonic hybrids

Magnetic hyperthermia which exploits the heat generated by magnetic nanoparticles (MNPs) when exposed to an alternative magnetic field (AMF) is now in clinical trials for the treatment of cancers. However, this thermal therapy requires a high amount of MNPs in the tumor to be efficient. On the contrary the hot spot local effect refers to the use of specific temperature profile at the vicinity of nanoparticles for heating with minor to no long-range effect. This magneto-thermal effect can be exploited as a relevant external stimulus to temporally and spatially trigger drug release. In this review, we focus on recent advances in magnetic hyperthermia. Indirect experimental proofs of the local temperature increase are first discussed leading to a good estimation of the temperature at the surface (from 0.5 to 6 nm) of superparamagnetic NPs. Then we highlight recent studies illustrating the hot-spot effect for drug-release. Finally, we present another recent strategy to enhance the efficacity of thermal treatment by combining photothermal therapy with magnetic hyperthermia mediated by magneto-plasmonic nanoplatforms.

Bioactive Glasses and Glass-Ceramics for Healthcare Applications in Bone Regeneration and Tissue Engineering

The discovery of bioactive glasses (BGs) in the late 1960s by Larry Hench et al. was driven by the need for implant materials with an ability to bond to living tissues, which were intended to replace inert metal and plastic implants that were not well tolerated by the body. Among a number of tested compositions, the one that later became designated by the well-known trademark of 45S5 Bioglass® excelled in its ability to bond to bone and soft tissues. Bonding to living tissues was mediated through the formation of an interfacial bone-like hydroxyapatite layer when the bioglass was put in contact with biological fluids in vivo. This feature represented a remarkable milestone, and has inspired many other investigations aiming at further exploring the in vitro and in vivo performances of this and other related BG compositions. This paradigmatic example of a target-oriented research is certainly one of the most valuable contributions that one can learn from Larry Hench. Such a goal-oriented approach needs to be continuously stimulated, aiming at finding out better performing materials to overcome the limitations of the existing ones, including the 45S5 Bioglass®. Its well-known that its main limitations include: (i) the high pH environment that is created by its high sodium content could turn it cytotoxic; (ii) and the poor sintering ability makes the fabrication of porous three-dimensional (3D) scaffolds difficult. All of these relevant features strongly depend on a number of interrelated factors that need to be well compromised. The selected chemical composition strongly determines the glass structure, the biocompatibility, the degradation rate, and the ease of processing (scaffolds fabrication and sintering). This manuscript presents a first general appraisal of the scientific output in the interrelated areas of bioactive glasses and glass-ceramics, scaffolds, implant coatings, and tissue engineering. Then, it gives an overview of the critical issues that need to be considered when developing bioactive glasses for healthcare applications. The aim is to provide knowledge-based tools towards guiding young researchers in the design of new bioactive glass compositions, taking into account the desired functional properties.