Evaluation of a nanocomposite of PEG-curcumin-gold nanoparticles as a near-infrared photothermal agent: an in vitro and animal model investigation.

Hyperthermia is a promising alternative modality for the conventional cancer treatments. Nanoparticle-mediated photothermal therapy (PTT) has been widely applied for hyperthermia cancer therapy by a near-infrared light irradiation. Some special nanoparticles can convert light energy into heat and destroy the tumor cells. Inspired from the photothermal efficacy of the gold nanoparticles, here we synthesized, characterized, and applied novel photothermal polyethylene glycol-curcumin-gold nanoparticles (PEG-Cur-Au NPs) in cancer PTT. The effect of PEG-Cur-Au NPs upon irradiation by an 808-nm laser on C540 (B16/F10) cell line as well as implanted (bearing) melanoma tumor in inbred C57 mice was investigated. In vitro temperature increment, cell viability evaluation, and histological analyses were performed. The results showed a dose-dependent cytotoxicity of PEG-Cur-Au NPs toward C540 (B16/F10) cell line at concentrations ≥ 25 µg mL-1 with an IC50 value of 42.7 µg mL-1 in dark (and with no toxicity for 10 µg mL-1). On the other hand, 808-nm laser irradiation alone (without using PEG-Cur-Au NPs) for 10 min induced killing effect on the C540 (B16/F10) cell line in a laser power-dependent manner at power density > 0.5 W cm-2 (no toxicity for 0.5 W cm-2). However, PPT using PEG-Cur-Au NPs was tremendously observed after laser illumination. Even under laser irradiation at a power density of 0.5 W cm-2 of PEG-Cur-Au NPs of concentrations < 10 µg mL-1, PTT of the cells was substantial. Histological analyses and volume measurements of the induced tumors in the mice revealed an appropriate control of the tumors upon PTT by PEG-Cur-Au NPs. Combination of PEG-Cur-Au NP administration and 808-nm diode laser irradiation destroyed the melanoma cancer cells in the animal model.

An ultrasensitive electrochemical genosensor for Brucella based on palladium nanoparticles.

Palladium nanoparticles were potentiostatically electrodeposited on a gold surface at a highly negative potential. The nanostructure, as a transducer, was utilized to immobilize a Brucella-specific probe and the process of immobilization and hybridization was detected by electrochemical methods. The proposed method for detection of the complementary sequence and a non-complementary sequence was applied. The fabricated genosensor was evaluated for the assay of the bacteria in the cultured and human samples with and without PCR. The genosensor could detect the complementary sequence with a sensitivity of 0.02 µA dm(3) mol(-1), a linear concentration range of 1.0 × 10(-12) to 1.0 × 10(-19) mol dm(-3), and a detection limit of 2.7 × 10(-20) mol dm(-3).

Photothermal cancer therapy by gold-ferrite nanocomposite and near-infrared laser in animal model.

Surface plasmon resonance effect of gold nanostructures makes them good candidates for photothermal therapy (PTT) application. Herein, gold-ferrite nanocomposite (GFNC) was synthesized and characterized as a photothermal agent in PTT. The aim of this study was to investigate the effect of GFNC upon laser irradiation on treatment of cancer in mice bearing melanoma cancer. Thirty mice received 1.5 × 10(6) B16/F10 cells subcutaneously. After 1 week, the mice bearing solid tumor were divided into four groups: control group (without any treatment), laser group (received laser irradiation without GFNC injection), GFNC group (only received intratumorally GFNC), and GFNC + laser group (received intratumorally GFNC upon laser irradiation). In GFNC + laser group, 200 µL of fluid, 1.3 × 10(-7) mol L(-1) gold nanoparticles, was injected intratumorally and immediately the site of tumor was exposed to continuous wave diode laser beam (808 nm, 1.6 W cm(-2)) for 15 min. All mice but four were euthanized 24 h after treatment to compare the necrotic surface area histologically by using measuring graticule. Statistical analyses revealed significant differences in necrosis extent for GFNC + laser group, compared to other groups. Four subjects (control group and GFNC + laser group, two mice each) were kept for longitudinal study. Histological analyses and tumor volume measurements of the four subjects indicated that tumor in GFNC + laser group was controlled appropriately. It was concluded that combining an 808-nm laser at a power density of 1.6 W cm(-2) with GFNC has a destruction effect in melanoma cancer cells in an animal model.

An amplified sonodynamic therapy by a nanohybrid of titanium dioxide-gold-polyethylene glycol-curcumin: HeLa cancer cells treatment in 2D monolayer and 3D spheroid models.

The utilization of ultrasound (US) to activate sonosensitizers for sonodynamic therapy (SDT) has faced challenges such as low activation efficiency and limited therapeutic outcomes, which have hampered its clinical applications. In this study, a nanohybrid of titanium dioxide-gold-polyethylene glycol-curcumin (TiO2-Au-PEG-Cur NH), as a novel US sensitizer, was synthesized, characterized, and applied for SDT of HeLa cancer cells in 2D monolayer model, and also a 3D spheroid model to bridge the gap between 2D cell culture and in vivo future studies. TiO2-Au-PEG-Cur NH contained TiO2 nanoparticles of 36 ± 11 nm in diameter, PEG-curcumin as a filler, and gold nanoparticles of 21 ± 7 nm in diameter with a high purity and a 35:17 of Ti:Au ratio (W/W), and it had a band gap of 2.4 eV, a zeta potential of -23 ± 7 mV, high stability upon US radiation cycles as well as one year storage. SDT of HeLa cells using TiO2-Au-PEG-Cur NH was investigated in the courses of cytotoxicity assessment in vitro, reactive oxygen species (ROS) generation capability, colony formation, cell migration, and the way to form spheroid. IC50 values of 122 and 38 µg mL-1 were obtained for TiO2-Au-PEG-Cur NH without and with US radiation, respectively. TiO2-Au-PEG-Cur NH not only exhibited an inherent capacity to generate ROS, but also represented an excellent therapeutic performance on the cancer cells through ROS generation and enhanced inhibitory effects on cell migration and spheroid formation.

Simultaneous chemotherapy/sonodynamic therapy of the melanoma cancer cells using a gold-paclitaxel nanostructure.

Nanodrug delivery systems are novel strategies for tumor treatment since delivery of chemotherapy drugs such as paclitaxel (PTX) is associated with substantial challenges due to its poor aqueous solubility. In addition, sonodynamic therapy (SDT) is a promising approach that can increase the uptake, accumulation, and dispersion of desirable amounts of the drugs by activating sonosensitizer and enhancing cell membrane permeability. Herein, gold-paclitaxel nanoparticles (Au-PTX NPs) were synthesized and characterized to evaluate the cytotoxicity toward C540 cancer cells in comparison of free PTX, AuNPs, and AuNPs+free PTX in the absence and presence of ultrasound radiation. Evidence shows that AuNPs have a median diameter size of 95.0 ± 15.4, while the size of Au-PTX NPs is roughly 219.7 ±  40.4 nm. Negative zeta-potential results indicate high stability and good dispersion of nanoparticles. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay results revealed that Au-PTX NPs increased the cytotoxicity compared to other treatment groups that ensure the great potential of AuNPs as a promising nano-carrier for PTX drug delivery. Moreover, the viability of C540 cells treated by Au-PTX NPs under ultrasound radiation was decreased significantly by generating more reactive oxygen species (ROS) upon STD, with representing synergism effects confirming the role of gold nanoparticles as an excellent sonosensitizer and the role of SDT as an adjunctive treatment method with chemotherapy.

An electrocatalytic transducer for L-cysteine detection based on cobalt hexacyanoferrate nanoparticles with a core-shell structure.

The electrocatalytic oxidation of L-cysteine (CySH) was studied on cobalt hexacyanoferrate nanoparticles with a core-shell structure (iron(III) oxide core-cobalt hexacyanoferrate shell) using cyclic voltammetry and chronoamperometry. Voltammetric studies represented two quasi-reversible redox transitions for the nanoparticles in phosphate buffer solution (pH 7.4). In the presence of CySH, the anodic peak current of the Fe(II)/Fe(III) transition was increased, followed by a decrease in the corresponding cathodic peak current, whereas the peak currents related to the Co(II)/Co(III) transition almost remained unchanged. The results indicated that the nanoparticles oxidized CySH via a surface mediation electrocatalytic mechanism. The catalytic rate constant, the electron transfer coefficient, and the diffusion coefficient involved in the electrooxidation process of CySH are reported here. Ultrasensitive and time-saving determination procedures were developed for the analysis of the CySH, and the corresponding analytical parameters are reported. According to the proposed methods, CySH was determined with detection limits of 40 and 20 nm in batch and flow systems, respectively. The proposed amperometric method was also applied to the analysis of CySH in human urine and serum blood samples.

Photo-genosensor for Trichomonas vaginalis based on gold nanoparticles-genomic DNA.

Trichomoniasis, an infectious disease caused by a parasite called Trichomonas vaginalis (T. vaginalis), enhances the risk of HIV infection, cervical and prostate cancer, and infertility. Therefore, efforts have to be made for accurate, specific, and rapid diagnosise and treatment of trichomoniasis. Today, optical nanosensors have created an opportunity for diagnosis without sophisticated and expensive tools and the need for expertise; at the same time, they are highly sensitive and fast. An optical nano-genosensor was designed by conjugation of gold nanoparticles and a specific oligonucleotide (AuNPs-probe) from repeated DNA target for specific and sensitive polymerase chain reaction diagnosis of T. vaginalis gene sequence (L23861.1). The hybridization of AuNPs-probe was investigated with different concentrations of complementary sequence in synthesized target, gene sequence of standard T. vaginalis genomic DNA extraction, and PCR products of genomic DNA samples extracted from patients. Negative samples including synthesized non-complementary sequence, genomics DNA of other pathogens, and genomics DNA of healthy persons were considered for proof of the accuracy of the sensor function. The occurrence of correct hybridization was detected by adding acid to the medium and observing the changes in the color of the medium and spectroscopic spectrum. Based on spectrophotometric results, the fabricated genosensor had detection limits of 35.16 and 31 pg µL-1 for the detection of synthetic target and genomic DNA sequences, respectively. The results confirmed the correct function of genosensor for the detection of T. vaginalis in clinical samples. Advantages such as low cost, visual detection, speed, and easy diagnosis encourage the use of this sensor in pathogen detection in the future.

Curcumin-gold-polyethylene glycol nanoparticles as a nanosensitizer for photothermal and sonodynamic therapies: In vitro and animal model studies.

Photothermal and ultrasound therapies are novel non-invasive strategies for tumor treatment which are equipped with a photosensitizer and sonosensitizer subsequent activation by laser irradiation and ultrasound exposure. In this study, curcumin-gold-polyethylene glycol nanoparticles (Cur-Au NPs-PEG) were synthesized, and the dual role in photothermal (PTT) and sonodynamic (SDT) therapies of melanoma cancer was evaluated. The toxicity effect of Cur-Au NPs-PEG against a mouse malignant melanoma cell line C540 (B16/F10) was firstly inspected in vitro. Cur-Au NPs-PEG provided a hyperthermal microenvironment and generated reactive oxygen species upon PTT and STD, respectively, with representing synergism effects. Studies in vivo in a tumor-bearing animal also demonstrate the superiority of PTT and SDT in destroying melanoma tumor.

An impedimetric genosensor for Leishmania infantum based on electrodeposited cadmium sulfide nanosheets.

It is estimated that there are 400000 new cases of visceral leishmaniasis each year, with about 30,000 deaths. Therefore, detection of this pathogen and its species is highly vital for overall health of the community. In the present research, a DNA-based biosensor, namely genosensor, was introduced for detection of genomic DNA of Leishmania infantum. The genosensor was fabricated based on the transduction of cadmium sulfide nanosheets and recognition of a particular single stranded DNA sequence, and worked in label-, marker-, tag- and PCR-free manners. Impedimetric measurements were performed in a wide range of frequency (recording Nyquist diagrams) without applying external force (working at open circuit potential) upon hybridization of DNA targets with the cadmium sulfide nanosheets surface-immobilized probe. The genosensor detected the complementary DNA strand in a concentration range of 1.0 × 10-14 to 1.0 × 10-6 mol L-1 and a detection limit (DL) of 0.81 fmol L-1 (6.5 fg mL-1), and genomic DNA of Leishmania infantum in a concentration range of 5-50 ng µL-1 and a DL of 1.2 ng µL-1. The genosensor had a very good selectivity, fabrication reproducibility and stability, and was applicable for practical applications.

Advances in prostate specific antigen biosensors-impact of nanotechnology.

Prostate cancer is one of the most dangerous and deadly cancers in elderly men. Early diagnosis using prostate-specific antigen (PSA) facilitates disease detection, management and treatment. Biosensors have recently been used as sensitive, selective, inexpensive and rapid diagnostic tools for PSA detection. In this review, a variety of PSA biosensors such as aptasensors, peptisensors and immunesensors are highlighted. These use aptamers, peptides and antibodies in the biorecognition element, respectively, and can detect PSA with very high sensitivity via electrochemical, electrochemiluminescence, fluorescence and surface-enhanced Raman spectroscopy. To improve the sensitivity of most of these PSA biosensors, different nanostructured materials have played a critical role.

An electrochemical signal-on apta-cyto-sensor for quantitation of circulating human MDA-MB-231 breast cancer cells by transduction of electro-deposited non-spherical nanoparticles of gold.

A highly simple, sensitive, specific and low-cost electrochemical apta-cyto-sensor for determination of circulating human MDA-MB-231 breast cancer cells was fabricated. Non-spherical nanoparticles of gold were electro-deposited in the presence of ethosuximide as a shape directing and size controlling agent. The nanoparticles had dimensions ranging 50-150 nm, and covered the underlying surface with a roughness factor of 8.03. The Non-spherical nanoparticles were then employed as the apta-cyto-sensor transducer. A 83-mer DNA aptamer that is specific to capturing the cell surface proteins was immobilized on the transducer surface, and binding with the cells was followed using the ferro/ferricyanide redox marker. The aptamer was immobilized within ∼200 min on the transducer surface. The cells were quantified with an equation of regression of ΔIp(µA) = (1.028 ±â€¯0.027) log (C (cell mL-1)) + (0.2199 ±â€¯0.0944), a sensitivity of 1.028 µA (log (concentration / cell mL-1))-1 and a quantitation limit of 2 cell mL-1, in a concentration range of 5 to 2 × 106 cell mL-1. The apta-cyto-sensor selectivity was also evaluated toward AsPC-1, Calu-6, HeLa, MCF-7 and melanoma B16/F10 cell lines. The apta-cyto-sensor had a fabrication reproducibility of 4.2%, regeneration capability of 5.1%, a stability of 35 days, and a potential application for the detection of MDA-MB-231 cells in the spiked blood serum samples with a sensitivity of 0.8975 µA (log (concentration / cell mL-1))-1 and a quantitation limit of 5 cell mL-1, in a concentration range of 10 to 1 × 103 cell mL-1. The apta-cyto-sensor would be applicable for breast cancer diagnosis at early stage.

Photothermal/sonodynamic therapy of melanoma tumor by a gold/manganese dioxide nanocomposite: In vitro and in vivo studies.

Nanosized materials have favorable applications in nanomedicine including photothermal therapy (PTT) and sonodynamic therapy (SDT) of most malignancies. Since conventional methods of cancer treatment encounter limitations, development of other efficient routes is quite necessary. In this study, a gold/manganese dioxide nanocomposite (Au/MnO2 NC) was synthesized as a novel photo- and sono- responsive nanomaterial that was activated upon laser light of 808-nm wavelength irradiation or ultrasound exposure for cancer treatment applications. The synthesized nanocomposite comprised gold nanoparticles of about 125 ±â€¯66 nm in diameter adhered to manganese dioxide nanoroads of 77 ±â€¯30 nm in diameter and up to 2 µm length. Au/MnO2 NC represented a very good photothermal and sonodynamic conversion ability. Cytotoxicity of Au/MnO2 NC toward the C540 (B16/F10) cell line was evaluated through thermal ablation and reactive oxygen species (ROS) generation upon phototherapy and sonotherapy, respectively. Intratumoral injection of a low-dose of Au/MnO2 NC into a melanoma tumor-bearing animal model followed by laser and ultrasound radiation led to necrosis in the tumor tissue. The findings revealed that Au/MnO2 NC is aphotosensitizer/sonosensitizer for PTT and SDT of cancer.

Combined X-ray radiotherapy and laser photothermal therapy of melanoma cancer cells using dual-sensitization of platinum nanoparticles.

Metal nanostructures are promising agents sensitizing by laser light and X-ray in photothermal therapy (PTT) and radiotherapy (RT) of cancer that improve treatment strategies of cancer. Nanoscale platinum materials are favorable in nanomedicine applications. In this study, platinum nanoparticles (PtNPs) were synthesized and applied for cancer therapy upon 808-nm laser light and X-ray radiation, or their combination. Two power densities of laser (1.0 and 1.5 W cm-2) and three X-ray doses (2, 4 and 6 Gy) were selected for irradiation of B16/F10 cell line at 24 and 72 h-post treatment. The synthesized PtNPs had a spherical shape with a diameter of 12.2 ± 0.7 nm, and were cytocompatible up to 250 µg mL-1. A photothermal conversion activity in a concentration-dependent manner at 72 h-post treatment was observed. Also, PtNPs represented cytotoxicity upon X-ray radiation doses of 2, 4, and 6 Gy after 24 h, while, 72-h time passing led to deeper outcomes. Dual radiation of laser light and X-ray into PtNPs considerably improved the treatment via reactive oxygen species (ROS) production. PtNPs can act as a novel dual absorber of laser light and X-ray, a common sensitizer, for treatment of cancer. The results of this study can be considered after further clinical investigations for treatment of tumor models.

A comparison between adjuvant and delivering functions of calcium phosphate, aluminum hydroxide and chitosan nanoparticles, using a model protein of Brucella melitensis Omp31.

Vaccination is the most efficient and economic approach used to hinder infection and intense consequences caused by viruses, bacteria, or other pathogenic organisms. Since the intrinsic immunogenicity of recombinant antigens is usually low, safe and potent vaccine adjuvants are needed to ensure the success of those recombinant vaccines. Nanoparticles (NPs) have attracted much interest as adjuvants and delivery systems. Previous studies have shown that calcium phosphate (CP), aluminum hydroxide (AH) and chitosan (CS) NPs are promising delivery systems for immunization. In addition, it has been determined that Omp31 is a good candidate for inducing protection against Brucella (B) melitensis and B. ovis. Our aim in the present study was to compare the functions of CP, AH and CS NPs for stimulation of the immune response and protection against B. melitensis by using omp31 as a model protein. Based on the cytokine profile and subclasses of the antibody, vaccination with Omp31 load CP (CP/Omp31) and Omp31 load AH (AH/Omp31) NPs induced T helper type 1 (Th1)-T helper type 2 (Th2) immune response, whereas immunization by Omp31 load CS (CS/Omp31) NPs induced Th1 immune response. CP/Omp31 NPs elicited protection toward B. melitensis challenge equivalent to the vaccine strain B. melitensis Rev.1. Compared to CS/Omp31 NPs, CP/Omp31 NPs elicited a low increase in protection level against B. melitensis 16 M. In conclusion, the obtained results indicated that CP NPs were potent antigen delivery systems to immunize brucellosis.

Antimicrobial Photothermal Treatment of Pseudomonas Aeruginosa by a Carbon Nanoparticles-Polypyrrole Nanocomposite.

BACKGROUND: Nowadays, it is needed to explore new routes to treat infectious bacterial pathogens due to prevalence of antibiotic-resistant bacteria. Antimicrobial photothermal therapy (PTT), as a new strategy, eradicates pathogenic bacteria. OBJECTIVE: In this study, the antimicrobial effects of a carbon nanoparticles-polypyrrole nanocomposite (C-PPy) upon laser irradiation were investigated to destroy the pathogenic gram-negative Pseudomonas aeruginosa. MATERIAL AND METHODS: In this experimental study, the bacterial cells were incubated with 50, 100 and 250 µg mL-1 concentrations of C-PPy and irradiated with a 808-nm laser at two power densities of 0.5 and 1.0 W cm-2. CFU numbers were counted for the irradiated cells, and compared to an untreated sample (kept in dark). To explore the antibacterial properties and mechanism(s) of C-PPy, temperature increment, reactive oxygen species formation, and protein and DNA leakages were evaluated. Field emission scanning electron microscopy was also employed to investigate morphological changes in the bacterial cell structures. RESULTS: The results showed that following C-PPy attachment to the bacteria surface, irradiation of near-infrared light resulted in a significant decrement in the bacterial cell viability due to photothermal lysis. Slightly increase in protein leakage and significantly increase intracellular reactive oxygen species (ROS) were observed in the bacteria upon treating with C-PPy. CONCLUSION: Photo-ablation strategy is a new minimally invasive and inexpensive method without overdose risk manner for combat with bacteria.

Repression of melanoma tumor in vitro and in vivo by photothermal effect of carbon xerogel nanoparticles.

Nanosized carbonaceous materials are favorable in biomedicine applications including photothermal therapy (PTT) of cancer. Since conventional strategies of cancer treatment have not responded to this serious disease, development of efficient alternative and promising strategies is highly desirable. In this study, carbon xerogel nanoparticles (CX-NPs) were synthesized as a novel photothermal nanomaterial and activated upon laser light of 808-nm wavelength for cancer phototherapy application. The synthesized CX-NPs had a spherical shape with a size of about 16 nm that showed nice photothermal conversion ability. Upon light irradiation with a power density of 1.0 W cm-2 for 15 min, a temperature increment occurred. A concentration-dependent cytotoxicity was also obtained for CX-NPs toward the C540 (B16/F10) cell line upon light irradiation, while CX-NPs presented biocompatibility in the mice model in dark. Photothermal property of CX-NPs efficiently led to reduction in the cell viability. A low-dose of CX-NPs was also applied in PTT of a melanoma tumor-bearing animal model. Based on tumor histopathological evaluations and volume change measurements in mice, a very good control of tumor situations after PTT by CX-NPs was attained. The findings revealed that CX-NPs is a good and novel photoabsorber for PTT of cancer.

Sonodynamic cancer therapy by a nickel ferrite/carbon nanocomposite on melanoma tumor: In vitro and in vivo studies.

Reactive oxygen species (ROS)-mediated cancer therapy using light or ultrasound (US) has been widely approached as a non-invasive and inspiring alternative treatment. Sonodynamic therapy (SDT), a non-invasive therapeutic modality of cancer, is an outcome of low-intensity US effect on cancer cells using a sonosensitizer, which results in heat and ROS production followed by cell death. The aim of this study was synthesis, characterization and cancer SDT application of a nickel ferrite/carbon nanocomposite (NiFe2O4/C), as a sonosensitizer. SDT was carried out by applying a 1.0-MHz US radiation at 1.0 W cm-2 of power density and 100% pulse ratio for 60 s. A significant C540 (B16/F10) cell killing was observed in vitro due to ROS production of 100 µg mL-1 of NiFe2O4/C upon SDT. In addition, SDT of melanoma cancer in a mouse model using intratumorally injected NiFe2O4/C of 100 µg mL-1 produced remarkable efficacious recovery in the tumor and significant necrosis (up to 60%) in histological assessments, while injection of NiFe2O4/C or US irradiation alone induced no healing effect. Therefore, SDT using NiFe2O4/C attained success in destroying melanoma cancer and can be developed and introduced as an alternative treatment strategy for melanoma cancer. In furtherance of SDT, magnetic resonance (MR) imaging (1.5 T) in an agarose phantom indicated the effectiveness of NiFe2O4/C as a negative contrast agent in transverse relaxation time-weighted imaging with a corresponding relaxation rate (r2) of 78.9 mmol L-1 s-1. The results confirmed the applicability of the nanocomposite as a theranostics agent for simultaneous SDT and MR imaging.

Carbon@polypyrrole nanotubes as a photosensitizer in laser phototherapy of Pseudomonas aeruginosa.

Phototherapy has been offered as an alternative and promising antibacterial strategy to overcome the antibiotic resistance problem. This study evaluated the antibacterial and phototherapy effects of carbon nanotubes with a polypyrrole coating in a core@shell structure (CNTs@PPy) on Pseudomonas aeruginosa (P. aeruginosa). P. aeruginosa was treated with CNTs@PPy at different concentrations (50-500 µg mL-1) in dark or laser light irradiation with a wavelength of 808 nm, a power density of 1000 mW cm-2 for 20 min. Temperature increment, cell viability, formation of reactive oxygen species (ROS) and protein/nucleic acid leakage subsequent the P. aeruginosa treatment were evaluated. The results showed that near-infrared laser irradiation of CNTs@PPy caused to a temperature increment confirming the ability of powerful photokilling of P. aeruginosa in a photothermal route. On the other hand, while CNTs@PPy represented just a 30-50% P. aeruginosa killing rate in dark, laser irradiation of 250 and 500 µg mL-1 concentrations of CNTs@PPy resulted in a ˜70% P. aeruginosa killing rate, along with significant ROS production into the medium and protein and nucleic acid leakage from P. aeruginosa. These later effects were assigned to a photodynamic route activity of CNTs@PPy upon laser irradiation. Therefore, CNTs@PPy acted as a photosensitizer in both photothermal and photodynamic therapies to present an enhanced bactericidal activity to annihilate and destroyed the gram-negative bacteria P. aeruginosa, a cause of many infectious diseases.

Electrochemical biosensing of 16s rRNA gene sequence of Enterococcus faecalis.

Some of microorganisms are potential pathogens that can be infectious agents under some circumstances, and development of new detection methods of the pathogens is of high interest. In the present study, an Enterococcus faecalis (E. faecalis) DNA biosensor (ef-biosensor) was fabricated to quantify the bacterium genome. A specific E. faecalis DNA probe was selected from 16S rRNA sequence of E. faecalis and immobilized on a gold electrode surface in an optimized time to fabricate the ef-biosensor. The ef-biosensor detected a synthetic target of the probe with a detection limit of 3.3 amol L-1 and with a nice selectivity to resolve from one-, two- and three-base mismatched sequences. In addition, the bacterium genomic DNA was quantified with a detection limit of 7.1 × 10-9 ng mL-1 in a concentration range of 1.1 × 10-7 to 1.1 ng mL-1. The ef-biosensor had a long time stability, good fabrication reproducibility and good regeneration ability. The ef-biosensor was successfully applied for E. faecalis detection in human samples.

Enhanced melanoma cell-killing by combined phototherapy/radiotherapy using a mesoporous platinum nanostructure.

BACKGROUND: Metal nanomaterials have a significant potential as photosensitizer and radiosensitizer. The purpose of this study was to evaluate the cytotoxicity of a platinum mesoporous nanostructure (Pt MN) toward a melanoma cancer cell line upon combined laser radiation (808 nm, 1 and 1.5 W cm-2) and X-ray irradiation (6 MV, 2, 4, and 6 Gy). METHODS: Pt MN was synthesized by a simple procedure and characterized by field emission scanning and transmission electron microscopy. A mouse malignant melanoma cell line C540 (B16/F10) was treated with Pt MN, laser light and/or X-ray. RESULTS: Pt MN had a mesoporous structure with a sponge-resemble shape comprised of ensembles of very small adhered particles of <11 nm and about 5-nm pores. While Pt MN represented a low toxicity toward and considerable uptake into the cell line in a concentration range of 10-100 µg mL-1, laser light radiation alone was also not toxic, and X-ray irradiation alone induced a limited toxicity, Pt MN was toxic against the cells in a dose dependent manner upon laser light radiation, X-ray irradiation, or their combined exposure. The killing efficacy of Pt MN upon X-ray irradiation was more obvious at 72 h post-treatment. The combined exposure (laser radiation followed by X-ray irradiation) led to a deep cell killing and a very low melanoma cell viability (∼1%). Significant melanoma cancer cell killing of Pt MN was due to reactive oxygen species (ROS) production upon combined exposure of laser and X-ray, while cell killing upon laser light radiation was due to heat generation. CONCLUSION: Pt MN was introduced as a supreme laser/X-ray sensitizer for treatment of cancer with a high ability to produce ROS and a potent impact on decreasing cell viability.