Polyethyleneimine in designed nanocomposite based magnetic halloysite nanotubes for extraction and determination of gallic acid in green tea.

An innovative and simple nanocomposite denoted as MHNTs@PEI was synthesized for gallic acid (GA) analytical sample pretreatment. Polyethyleneimine (PEI) functionalized was binded onto magnetic halloysite nanotubes (MHNTs) to inhence adsorption capacity. MHNTs@PEI was obtained only through two steps modification (amination and PEI modification). Characterizations showed that there are layers of synthetic PEI on the tubular structure of the material and magnetic spheres on its surface, both indicating successful synthesis of the nanocomposite. Furthermore, the adsorption isotherms and kinetic modeling showed that the Langmuir model and pseudo-first-order model fit the adsorption data, respectively. MHNTs@PEI achieved an adsorption capacity of 158 mg·g-1. Overall, the abundant adsorption sites significantly improved the adsorption performance of the MHNTs@PEI. Regeneration tests demonstrated that the MHNTs@PEI exhibits effective adsorption, even after undergoing five consecutive cycles. Optimization of key parameters (ratio, volume of elution, elution time and frequency) in the process of adsorption and desorption was also conducted. The limit of detection (LOD) and that of the quantification (LOQ) were 0.19 and 0.63 µg·mL-1, respectively, and the recoveries were 95.67-99.43 %. Finally, the excellent magnetism (43.5 emu·g-1) and the adsorption feature of MHNTs@PEI enabled its successful utilization in analytical sample pretreatment through the extraction of GA from green tea.

Regulation of band gap and localized surface plasmon resonance by loading Au nanorods on violet phosphene nanosheets for photodynamic/photothermal synergistic anti-infective therapy.

In the face of the serious threat to human health and the economic burden caused by bacterial antibiotic resistance, 2D phosphorus nanomaterials have been widely used as antibacterial agents. Violet phosphorus nanosheets (VPNSs) are an exciting bandgap-adjustable 2D nanomaterial due to their good physicochemical properties, yet the study of VPNS-based antibiotics is still in its infancy. Here, a composite of gold nanorods (AuNRs) loaded onto VPNS platforms (VPNS/AuNR) is constructed to maximize the potential of VPNSs for antimicrobial applications. The loading with AuNRs not only enhances the photothermal performance via a localized surface plasmon resonance (LSPR) effect, but also enhances the light absorption capacity due to the narrowing of the band gap of the VPNSs, thus increasing the ROS generation capacity. The results demonstrate that VPNS/AuNR exhibits outstanding antibacterial properties and good biocompatibility. Attractively, VPNS/AuNR is then extensively tested for treating skin wound infections, suggesting promising in vivo antibacterial and wound-healing features. Our findings may open a novel direction to develop a versatile VPNS-based treatment platform, which can significantly boost the progress of VPNS exploration.

Synergistic chemo-photothermal therapy using gold nanorods supported on thiol-functionalized mesoporous silica for lung cancer treatment.

Cancer therapy necessitates the development of novel and effective treatment modalities to combat the complexity of this disease. In this project, we propose a synergistic approach by combining chemo-photothermal treatment using gold nanorods (AuNRs) supported on thiol-functionalized mesoporous silica, offering a promising solution for enhanced lung cancer therapy. To begin, mesoporous MCM-41 was synthesized using a surfactant-templated sol-gel method, chosen for its desirable porous structure, excellent biocompatibility, and non-toxic properties. Further, thiol-functionalized MCM-41 was achieved through a simple grafting process, enabling the subsequent synthesis of AuNRs supported on thiol-functionalized MCM-41 (AuNR@S-MCM-41) via a gold-thiol interaction. The nanocomposite was then loaded with the anticancer drug doxorubicin (DOX), resulting in AuNR@S-MCM-41-DOX. Remarkably, the nanocomposite exhibited pH/NIR dual-responsive drug release behaviors, facilitating targeted drug delivery. In addition, it demonstrated exceptional biocompatibility and efficient internalization into A549 lung cancer cells. Notably, the combined photothermal-chemo therapy by AuNR@S-MCM-41-DOX exhibited superior efficacy in killing cancer cells compared to single chemo- or photothermal therapies. This study showcases the potential of the AuNR@S-MCM-41-DOX nanocomposite as a promising candidate for combined chemo-photothermal therapy in lung cancer treatment. The innovative integration of gold nanorods, thiol-functionalized mesoporous silica, and pH/NIR dual-responsive drug release provides a comprehensive and effective therapeutic approach for improved outcomes in lung cancer therapy. Future advancements based on this strategy hold promise for addressing the challenges posed by cancer and transforming patient care.

Selective enhanced cytotoxicity of amino acid deprivation for cancer therapy using thermozyme functionalized nanocatalyst.

BACKGROUND: Enzyme therapy based on differential metabolism of cancer cells has demonstrated promising potential as a treatment strategy. Nevertheless, the therapeutic benefit of reported enzyme drugs is compromised by their uncontrollable activity and weak stability. Additionally, thermozymes with high thermal-stability suffer from low catalytic activity at body temperature, preventing them from functioning independently. RESULTS: Herein, we have developed a novel thermo-enzymatic regulation strategy for near-infrared (NIR)-triggered precise-catalyzed photothermal treatment of breast cancer. Our strategy enables efficient loading and delivery of thermozymes (newly screened therapeutic enzymes from thermophilic bacteria) via hyaluronic acid (HA)-coupled gold nanorods (GNRs). These nanocatalysts exhibit enhanced cellular endocytosis and rapid enzyme activity enhancement, while also providing biosafety with minimized toxic effects on untargeted sites due to temperature-isolated thermozyme activity. Locally-focused NIR lasers ensure effective activation of thermozymes to promote on-demand amino acid deprivation and photothermal therapy (PTT) of superficial tumors, triggering apoptosis, G1 phase cell cycle arrest, inhibiting migration and invasion, and potentiating photothermal sensitivity of malignancies. CONCLUSIONS: This work establishes a precise, remotely controlled, non-invasive, efficient, and biosafe nanoplatform for accurate enzyme therapy, providing a rationale for promising personalized therapeutic strategies and offering new prospects for high-precision development of enzyme drugs.

Pectin wrapped halloysite nanotube reinforced Polycaprolactone films for potential wound healing application.

The current research work focuses on preparing the polycaprolactone (PCL) based nanocomposite films embedded with surface modified Halloysite Nanotube (HNT). The avenue of the study is to unravel the applicability of polymer nanocomposites for wound healing. The flexible property of HNT was taken as the major force to accomplish the addition of biopolymer pectin onto its surface. Functionalization of HNT with pectin has certainly enhanced its binding nature with the polymer. The PCL nanocomposite films were characterized by several promising techniques such as FTIR, XRD, DSC-TGA, FESEM, TEM, AFM, and mechanical properties were too examined along. When compared to the plane PCL film, the nanocomposite films manifested favorable results in terms of mechanical and chemical properties. Additionally, biometric studies such as in-vitro swelling, enzymatic degradation, and hemolysis performed on the films gave extremely good results. The haemolytic percentage recorded for the films exhibited a steady decrease with increasing amount of nanofillers. The MTT assay showed cell proliferation and its increase as the embedded HNT is more in the matrix. Wound closure study performed on NIH3T3 cell line with 1, 3 and 5wt% of films has given a strong proof for the involvement of polymer and HNT in the healing procedure.

Preparation and photothermal therapy of gold nanorods modified by Belamcanda chinensis (L.) DC polysaccharide.

In recent years, the application of nanoparticles formed by coupling metal nanomaterials of photothermal therapy with polysaccharides as modified carriers in the targeted treatment of liver cancer has attracted extensive attention. In the present work, an undescribed homogeneous polysaccharide BCP50-2 was obtained from Belamcanda chinensis (L.) DC. The structural analysis displayed that BCP50-2 contained galactose and a small amount of arabinose, and was mainly composed of six monosaccharide residues: →3,5)-α-l-Araf-(1→, →4)-ß-d-Galp-(1→, →4,6)-ß-d-Galp-(1→, →3)-α-l-Galp-(1→, terminal α-l-Araf, and terminal ß-d-Galp. To enhance the antitumor activity of BCP50-2, BCP50-2-AuNRs were prepared by coupling BCP50-2 with gold nanorods for the treatment of liver cancer. BCP50-2-AuNRs were rod-shaped with a long diameter of 26.8 nm and had good photothermal conversion effects. Under near-infrared (NIR) light irradiation, BCP50-2-AuNRs possessed photothermal effects and suppressed the growth of HepG2, A549, and MCF-7 cells. In addition, BCP50-2-AuNRs inhibited the development of liver cancer by inducing cell apoptosis, arresting the cell cycle in G2/M phases, and inhibiting cell migration. Moreover, BCP50-2-AuNRs inhibited tumor proliferation, migration, and angiogenesis in zebrafish. In summary, BCP50-2-AuNRs may be potentially useful for cancer treatment.

Promoting Intratumoral Drug Accumulation by Bio-Membrane Regulated Active Targeting for Tumor Photothermal Therapy.

Introduction: Insufficient tumor permeability and inadequate nanoparticle retention continue to be significant limitations in the efficacy of anti-tumor drug therapy. Numerous studies have focused on enhancing tumor perfusion by improvement of tumor-induced endothelial leakage, often known as the enhanced permeability and retention (EPR) effect. However, these approaches have produced suboptimal therapeutic outcomes and have been associated with significant side effects. Therefore, in this study, we prepared tumor cell membrane-coated gold nanorods (GNR@TM) to enhance drug delivery in tumors through homogeneous targeting of tumor cell membranes and in situ real-time photo-controlled therapy. Methods: Here, we fabricated GNR@TM, and characterized it using various techniques including Ultraviolet-Visible (UV-Vis) spectrophotometer, particle size analysis, potential measurement, and transmission electron microscopy (TEM). The cellular uptake and cytotoxicity of GNR@TM were analyzed by flow cytometry, confocal laser scanning microscopy (CLSM), TEM, CCK8 assay and live/dead staining. Tissue drug distribution was determined by inductively coupled plasma mass spectrometry (ICP-MS) and immunofluorescence staining. Furthermore, to evaluate the therapeutic effect, mice bearing MB49 tumors were intravenously administered with GNR@TM. Subsequently, near-infrared (NIR) laser therapy was performed, and the mice's tumor growth and body weight were monitored. Results: The tumor cell membrane coating endowed GNR@TM with extended circulation time in vivo and homotypic targeting to tumor, thereby enhancing the accumulation of GNR@TM within tumors. Upon 780 nm laser, GNR@TM exhibited excellent photothermal conversion capability, leading to increased tumor vascular leakage. This magnification of the EPR effect induced by NIR laser further increased the accumulation of GNR@TM at the tumor site, demonstrating strong antitumor effects in vivo. Conclusion: In this study, we successfully developed a NIR-triggered nanomedicine that increased drug accumulation in tumor through photo-controlled therapy and homotypic targeting of the tumor cell membrane. GNR@TM has been demonstrated effective suppression of tumor growth, excellent biocompatibility, and significant potential for clinical applications.

Effective Distribution of Gold Nanorods in Ordered Thick Mesoporous Silica: A Choice of Noninvasive Theranostics.

Porous silica coated gold nanorod core-shell structures demonstrate a multifunctional role in bioimaging, drug delivery, and cancer therapeutics applications. Here, we address a new approach for effective distribution of gold nanorods (GNRs) in a mesoporous silica (MS) shell, viz., one nanorod in one silica particle (GMS). We have studied that silica coating presents major advantages for the better biocompatibility and stability of GNRs. In this study, two different thicknesses of silica shell over GNRs have been discussed as per the application's need; GNRs in thin silica (11 nm) are fit for phototherapy and bioimaging, whereas thick and porous silica (51 nm) coated gold nanorods are suitable for triggered drug delivery and theranostics. However, effective distribution of GNRs in ordered architecture of thick mesoporous silica (MS, more than 50 nm thickness) with high surface area (more than 1000 m2/g) is not well understood so far. Here, we present methodical investigations for uniform and highly ordered mesoporous silica coating over GNRs with tunable thickness (6 to 51 nm). Judicious identification and optimization of different reaction parameters like concentrations of silica precursor (TEOS, 1.85-43.9 mM), template (CTAB, 0.9-5.7 mM), effect of temperature, pH (8.6-10.8), stirring speed (100-400 rpm), and, most importantly, the mode of addition of TEOS with GNRs have been discussed. Studies with thick, porous silica coated GNRs simplify the highest ever reported surface area (1100 m2/g) and cargo capacity (57%) with better product yield (g/batch). First and foremost, we report a highly scalable (more than 500 mL) and rapid direct deposition of an ordered MS shell around GNRs. These engineered core-shell nanoparticles demonstrate X-ray contrast property, synergistic photothermal-chemotherapeutics, and imaging of tumor cell (96% cell death) due to released fluorescent anticancer drug molecules and photothermal effect (52 °C) of embedded GNRs. A deeper insight into their influence on the architectural features and superior theranostics performances has been illustrated in detail. Hence, these findings indicate the potential impact of individual GMS for image guided combination therapeutics of cancer.

Two-dimensional peptide nanosheets functionalized with gold nanorods for photothermal therapy of tumors.

Self-assembled peptide nanomaterials exhibit great potential for applications in materials science, energy storage, nanodevices, analytical science, biomedicine, tissue engineering, and others due to their tailorable ordered nanostructures and unique physical, chemical, and biological properties. Although one-dimensional peptide nanofibers and nanotubes have been widely used for biomedical applications, the design and synthesis of two-dimensional (2D) peptide nanostructures for cancer therapy remain challenging. In this work, we describe the creation of 2D biocompatible peptide nanosheets (PNSs) through molecular self-assembly, which can provide support matrixes for conjugating gold nanorods (AuNRs) to form high-performance 2D nanomaterials for photothermal conversion. After molecular modification, AuNRs can be chemically conjugated onto the surface of 2D PNSs, and the created PNS-AuNR nanohybrids serve as a potential nanoplatform for photothermal therapy of tumor cells. The obtained results indicate that both PNSs and AuNRs contribute to the improved efficiency of photothermal therapy (PTT) of tumors, in which 2D PNSs provide high biocompatibility and a large surface area for binding AuNRs, and AuNRs show a high PTT ability towards tumors. The strategies of molecular design and functional tailoring of self-assembled peptide nanomaterials shown in this study are valuable and inspire the synthesis of biomimetic nanomaterials for biomedicine and tissue engineering applications.

NIR-II Light-Activated Gold Nanorods for Synergistic Thermodynamic and Photothermal Therapy of Tumor.

There are tricky challenges in tumor therapy due to the hypoxic tumor microenvironment, inevitably inhibiting the treatment efficacy of the traditional photodynamic therapy (PDT), radiation therapy (RT), and sonodynamic therapy (SDT). Herein, to overcome tumor hypoxia limitation, we constructed a near-infrared II (NIR-II) light-triggered thermodynamic therapy (TDT) nanoplatform of Au@mSiO2-AIPH@PCM/PEG (ASAPP) by integrating the Au nanorods (Au NRs) and thermally activated alkyl free radical-releasing molecules (AIPH). Au NRs@mSiO2 was used as a photothermally responsive material and AIPH carrier, and the hot-melt phase-change material (PCM) was used as a capping agent to prevent leakage of AIPH during blood circulation. Upon NIR-II light irradiation, heat-triggered free radical release from AIPH was successfully achieved for killing cancer cells in vitro and in vivo without oxygen dependence, leading to synergistically enhanced antitumor therapy.

Engineering near-infrared laser-activated gold nanorod vesicles with upper critical solution temperature for photothermal therapy and chemotherapy.

Multimodal synergistic therapy based on nanomedicine drug delivery systems can achieve accurate cancer treatment. The anisotropy of gold nanorods (AuNRs) allows the adjustment of the longitudinal localized surface plasmon resonance absorption to the near-infrared band, which shows potential application in the field of photothermal therapy of cancer. Here, we report a new type of thermal-sensitive gold nanorod drug-loaded vesicles (UGRV-DOX) via the self-assembly of AuNRs modified with the amphiphilic polymer (PEG45-b-PS150) and upper critical solution temperature (UCST) polymer (P(AAm-co-AN)). The hollow structure of the vesicle can increase the drug loading capacity, and the polymers on its surface are intertwined to reduce drug leakage. As-prepared UGRV-DOX vesicles exhibits excellent photothermal conversion efficiency and can achieve light-controlled drug release. In vivo anti-tumor experiments showed that UGRV-DOX could ablate HepG2 transplanted tumors significantly under 808 nm laser irradiation, and the inhibition rate was as high as 99.3 %. These tumor-specific nanovesicles prefigure great potentials for high-precision cancer treatment.

Tailoring enzymatic loading capacity on CdS nanorods@ZnIn2S4 nanosheets 1D/2D heterojunctions: Toward ultrasensitive photoelectrochemical bioassay of tobramycin.

Despite advances in the development of photoelectrochemical (PEC) sensor, modulating the PEC response of assembled heterostructure interface is still a great challenge. Here, an ultrasensitive PEC aptasensor for tobramycin (TOB) assay was conducted based on one-dimensional/two-dimensional CdS nanorods@ZnIn2S4 nanosheets (1D/2D CdS NRs@ZnIn2S4 NSs) heterojunctions by tailoring enzymatic loading capacity. Firstly, alkaline phosphatase modified TOB aptamer (ALP-Apt) was linked via specific base complementary pairing, and insoluble precipitations were then produced through the ALP-triggered catalytic reaction with the aid of Ag+, which prevented the charge transfer and resulted in the decrement of photocurrent. In the presence of TOB, partial ALP-Apt detached from the electrode surface due to the strong affinity between TOB and its aptamer, leading to a reduction in the amount of ALP and insoluble precipitate, in turn the PEC response partially recovered. The photocurrents exhibited a wider linear range towards the TOB concentration of 1.0-5.0 × 104 pg mL-1, with a low detection limit of 0.96 pg mL-1. The constructed PEC aptasensor gained satisfactory results for TOB assay in milk samples as well, which also offered significant promise for other pollutants in environmental analysis.

Optimization of surface enhanced Raman scattering performance based on Ag nanoparticle-modified vanadium-titanium nanorods with tunable nanogaps.

The combination of new noble metal nanomaterials and surface enhanced Raman scattering (SERS) technology has become a new strategy to solve the problem of low sensitivity in the detection of traditional Chinese medicine. In this work, taking natural cicada wing (C.w.) as a template, by optimizing the magnetron sputtering experimental parameters for the growth of Ag nanoparticles (NPs) on vanadium-titanium (V-Ti) nanorods, the nanogaps between the nanorods were effectively regulated and the Raman signal intensity of the Ag15/V-Ti20/C.w. substrate was improved. The proposed homogeneous nanostructure exhibited high SERS activity through the synergistic effect of the electromagnetic enhancement mechanism at the nanogaps between the Ag NPs modified V-Ti nanorods. The analytical enhancement factor (AEF) value was as high as 1.819 × 108, and the limit of detection (LOD) was 1 × 10-11 M for R6G. The large-scale distribution of regular electromagnetic enhancement "hot spots" ensured the good reproducibility with the relative standard deviation (RSD) value less than 7.31%. More importantly, the active compound of Artemisinin corresponded the pharmacological effect of Artemisia annua was screened out by SERS technology, and achieved a LOD of 0.01 mg/l. This reliable preparation technology was practically applicable to produce SERS-active substrates in detection of pharmacodynamic substance in traditional Chinese medicine.

Rhodium-Tellurium Nanorod Synthesis Using Galvanic Replacement-Polyol Regrowth for Thermo-Dynamic Dual-Modal Cancer Phototherapy.

Rh is a noble metal introduced in bioapplications, including diagnosis and therapy, in addition to its consolidated utilization in organic catalysis and electrocatalysis. Herein, we designed the synthesis of highly crystalline Rh nanocrystal-decorated Rh-Te nanorods (RhTeNRs) through galvanic replacement of sacrificial Te nanorod (TeNR) templates and subsequent polyol regrowth. The obtained RhTeNRs showed excellent colloidal stability and efficient heat dissipation and photocatalytic activity under various laser irradiation wavelengths. Based on the confirmed biocompatibility, RhTeNRs were introduced into in vitro and in vivo cancer phototherapies. The results confirmed the selective physical death of cancer cells in the local area through laser irradiation. While chemotherapy does not guarantee successful treatment due to side effects and resistance, phototherapy using heat and reactive oxygen species generation of RhTeNRs induces physical death.

Keratin/alginate hybrid hydrogels filled with halloysite clay nanotubes for protective treatment of human hair.

Keratin/alginate hydrogels filled with halloysite nanotubes (HNTs) have been tested for the protective coating of human hair. Preliminary studies have been conducted on the aqueous colloidal systems and the corresponding hydrogels obtained by using Ca2+ ions as crosslinkers. Firstly, we have investigated the colloidal properties of keratin/alginate/HNTs dispersions to explore the specific interactions occurring between the biomacromolecules and the nanotubes. Then, the rheological properties of the hydrogels have been studied highlighting that the keratin/alginate interactions and the subsequent addition of HNTs facilitate the biopolymer crosslinking. Finally, human hair samples have been treated with the hydrogel systems by the dipping procedure. The protection efficiency of the hydrogels has been evaluated by studying the tensile properties of hair fibers exposed to UV irradiation. In conclusion, keratin/alginate hydrogel filled with halloysite represents a promising formulation for hair protective treatments due to the peculiar structural and rheological characteristics.

Cyclodextrin-Functionalized Gold Nanorods Loaded with Meclofenamic Acid for Improving N6-Methyladenosine-Mediated Second Near-Infrared Photothermal Immunotherapy.

Cancer immunotherapy has achieved considerable clinical progress in recent years on account of its potential to treat metastatic tumors and inhibit recurrence. However, low patient response rates and dose-limiting toxicity are the major limitations of immunotherapy. Nanoparticle-based photothermal immunotherapy can amplify antitumor immune responses, although poor tumor penetration depth of near-infrared radiation (NIR) and the immunosuppressive tumor microenvironment significantly dampen its effects. We designed a nanoplatform based on gold nanorods for NIR-II-mediated photothermal therapy (PTT) combined with N6-methyladenosine (m6A) demethylase inhibition to achieve enhanced photothermal immunotherapy against prostate cancer. The GNRs were assembled layer by layer with polystyrenesulfonate as the interconnecting layer and then coated with a cationic polymer of γ-cyclodextrin (CD)-cross-linked low-molecular-weight polyethylenimine that was conjugated to an 8-mer peptide targeting the prostate tumor-specific gastrin-releasing peptide receptor. The m6A RNA demethylase inhibitor meclofenamic acid (MA) was then loaded into the CD cavity through hydrophobic interactions. GNR-CDP8MA specifically targeted the prostate tumor cells and selectively accumulated at the tumor site in vivo. In addition, GNR-CDP8MA almost completely ablated prostate cancer cell-derived tumors upon 1208 nm laser irradiation. Mechanistically, NIR-II triggered the release of MA from GNR-CDP8MA, which increased global mRNA m6A methylation and decreased the stability of PDL1 transcripts. Furthermore, GNR-CDP8MA-mediated PTT-induced immunogenic cell death in the primary tumor and consequently enhanced antitumor immunity by activating the antigen-presenting dendritic cells and tumor-specific effector T cells in the metastatic tumors. This study offers insights into synergistic m6A RNA methylation and PTT as an effective strategy for cancer immunotherapy.

Liver cancer treatment with integration of laser emission and microwave irradiation with the aid of gold nanoparticles.

This paper studies the effectiveness of the integration of microwave field irradiation and laser emission in liver cancer therapy with the aid of gold nanorods, in order to find out the influences of these combinational methods in tumor necrosis. Hepatocellular carcinoma is a kind of liver cancer that usually has a complicated structure, including both of superficial and deep sections. In current research, in deep regions of cancerous tissue, microwave antenna is utilized and in superficial regions, laser beams are irradiated. A Pulsed laser with heating time of 50 s and cooling time of 20 s is utilized for hyperthermia treatment. It should be mentioned that gold nanorods are injected into the tumorous region to enhance the treatment process and reduce the patient's exposure time. Simulation results showed that at the first step, without any injection of gold nanoparticles, 0.17% of the tumor's volume encountered necrosis, while at the next stage, after injection of gold nanorods, the necrosis rate increased to 35%, which demonstrates the efficiency of gold nanorods injection on the tumor treatments. Furthermore, the combinational applying of both microwave antenna and laser illumination can eradiate the tumor tissue completely.

Antimicrobial potential and osteoblastic cell growth on electrochemically modified titanium surfaces with nanotubes and selenium or silver incorporation.

Titanium nanotube surfaces containing silver, zinc, and copper have shown antimicrobial effects without decreasing osteoblastic cell growth. In this in-vitro study we present first results on the biological evaluation of surface modifications by incorporating selenium and silver compounds into titanium-dioxide (TiO2) nanotubes by electrochemical deposition. TiO2-nanotubes (TNT) and Phosphate-doped TNT (pTNT) were grown on the surface of Ti6Al4V discs by anodization. Hydroxyapatite (HA), selenium (Se) and silver (Ag) compounds were incorporated by electrochemical deposition. Colony forming units of Staphylococcus epidermidis (DSM 3269) were significantly decreased in SepTNT (0.97 ± 0.18 × 106 CFU/mL), SepTNT-HA (1.2 ± 0.39 × 106 CFU/mL), AgpTNT (1.36 ± 0.42 × 106 CFU/mL) and Ag2SepTNT (0.999 ± 0.12 × 106 CFU/mL) compared to the non-modified control (2.2 ± 0.21 × 106 CFU/mL). Bacterial adhesion was calculated by measuring the covered area after fluorescence staining. Adhesion was lower in SepTNT (37.93 ± 12%; P = 0.004), pTNT (47.3 ± 6.3%, P = 0.04), AgpTNT (24.9 ± 1.8%; P < 0.001) and Ag2SepTNT (14.9 ± 4.9%; P < 0.001) compared to the non-modified control (73.7 ± 11%). Biofilm formation and the growth of osteoblastic cells (MG-63) was observed by using Crystal Violet staining. Biofilm formation was reduced in SepTNT (22 ± 3%, P = 0.02) and Ag2SepTNT discs (23 ± 11%, P = 0.02) compared to the non-modified control (54 ± 8%). In comparison with the non-modified control the modified SepTNT-HA and pTNT surfaces showed a significant higher covered area with osteoblastic MG-63-cells. Scanning electron microscope (SEM) images confirmed findings regarding bacterial and osteoblastic cell growth. These findings show a potential synergistic effect by combining selenium and silver with titanium nanotubes.

Enhancement of Thermoplasmonic Neural Modulation Using a Gold Nanorod-Immobilized Polydopamine Film.

Photothermal neural activity inhibition has emerged as a minimally invasive neuromodulation technology with submillimeter precision. One of the techniques involves the utilization of plasmonic gold nanoparticles (AuNPs) to modulate neural activity by photothermal effects ("thermoplasmonics"). A surface modification technique is often required to integrate AuNPs onto the neural interface. Here, polydopamine (pDA), a multifunctional adhesive polymer with a wide light absorption spectrum, is introduced both as a primer layer for the immobilization of gold nanorods (GNRs) on the neural interface and as an additional photothermal agent by absorbing near-infrared red (NIR) lights for more efficient photothermal effects. First, the optical and photothermal properties of pDA as well as the characteristics of GNRs attached onto the pDA film are investigated for the optimized photothermal neural interface. Due to the covalent bonding between GNR surfaces and pDA, GNRs immobilized on pDA showed strong attachment onto the surface, yielding a more stable photothermal platform. Lastly, when photothermal neural stimulation was applied to the primary rat hippocampal neurons, the substrate with GNRs immobilized on the pDA film allowed more laser power-efficient photothermal neuromodulation as well as photothermal cell death. This study suggests the feasibility of using pDA as a surface modification material for developing a photothermal platform for the inhibition of neural activities.

Escherichia coli Mimetic Gold Nanorod-Mediated Photo- and Immunotherapy for Treating Cancer and Its Metastasis.

Most cancer-related deaths are due to metastasis or recurrence. Therefore, the ultimate goal of cancer therapy will be to treat metastatic and recurrent cancers. Combination therapy for cancer will be one of trial for effective treating metastasis and recurrence. In this study, Escherichia coli-mimetic nanomaterials are synthesized using Escherichia coli membrane proteins, adhesion proteins, and gold nanorods, which are named E. coli mimetic AuNRs (ECA), for combination therapy against cancer and its recurrence. ECA treatment with 808 nm laser irradiation eliminates CT-26 or 4T1 tumors via a photothermal effect. ECA with laser irradiation induces activation of immune cells in the tumor-draining lymph nodes. The mice cured from CT-26 or 4T1 tumor by ECA are rechallenged with those cancer in the lung metastatic form, and the results showed that ECA treatment for the first CT-26 or 4T1 tumor challenge prevents cancer infiltration to the lung in the second challenge. This preventive effect of ECA against tumor growth in the second challenge is aided by cancer antigen-specific T cell immunity. Overall, these findings show that ECA is a nanomaterial with dual functions as a photothermal therapy for treating primary cancers and as immunotherapy for preventing recurrence and metastasis.