Synthesis of ZnS:Ag,Co water-soluble blue afterglow nanoparticles and application in photodynamic activation.

Silver and cobalt co-doped ZnS (ZnS:Ag,Co) water-soluble afterglow nanoparticles were synthesized using a wet chemistry method followed by aging at room temperature. The nanoparticles had a cubic zinc blende structure with average sizes of approximately 4 nm and emitted a blue fluorescence emission centered at 441 nm due to radiative transitions from surface defects to Ag(+) luminescent centers. Intense afterglow emission peaking at 475 nm from the obtained nanoparticles was observed and was red-shifted compared to the fluorescence emission peak. X-ray photoelectron spectroscopy revealed a large increase of O/S ratio, indicating a surface oxidation process during aging. The S vacancies produced accordingly may contribute to form more electron traps and enhance afterglow. The ZnS:Ag,Co afterglow nanoparticles have a very low dark-toxicity and are applied as a light source for photodynamic therapy activation by conjugating with protoporphyrin together. Our preliminary study has shown that the ZnS:Ag,Co afterglow nanoparticles can significantly reduce the x-ray dosage used in activation and thus may be a very promising candidate for future x-ray excited photodynamic therapy in deep cancer treatment.

Enhancement of protoporphyrin IX performance in aqueous solutions for photodynamic therapy.

Molecular modification of protoporphyrin IX (PpIX) was conducted to improve its water solubility and therapeutic performance for photodynamic therapy. The carboxylic acid and the two nitrogen atoms in the core of PpIX molecule were protonated following by conjugation with 3-aminopropyl triethoxysilane (APTES). Then, folic acid (FA) was conjugated to the APTES-coated PpIX (MPpIX) through chemical bonding between FA and protonated PpIX. The results showed that APTES coating can stabilize PpIX and increase its water solubility. Consequently, this leads to the enhancement in luminescence and singlet oxygen production. Upon X-ray irradiation, singlet oxygen can be detected in the MPpIX but not in PpIX. This means that MPpIX can be used for deep cancer treatment as X-ray can penetrate deeply into tissue. Molecular modification also reduces the dark toxicity of PPIX and increases their cell uptake. All these traits indicate that the Molecular modification of PpIX may potentially improve the efficacy of photodynamic therapy for cancer treatment.

X-ray-induced nanoparticle-based photodynamic therapy of cancer.

AIM: In this study, Ce(3+)-doped lanthanum(III) fluoride (LaF3:Ce(3+)) nanoparticles were synthesized by a wet-chemistry method in dimethyl sulfoxide (DMSO) and their application as an intracellular light source for photodynamic activation was demonstrated. MATERIALS & METHODS: The LaF3:Ce(3+)/DMSO nanoparticles have a strong green emission with a peak at approximately 520 nm, which is effectively overlapped with the absorption of protoporphyrin IX (PPIX). The nanoparticles were encapsulated into poly(D,L-lactide-co-glycolide (PLGA) microspheres along with PPIX. Upon irradiation with x-rays (90 kV), energy transfer from the LaF3:Ce(3+)/DMSO nanoparticles to PPIX occurs and singlet oxygen is generated for cancer cell damage. RESULTS: The LaF3:Ce(3+)/DMSO/PLGA or LaF3:Ce(3+)/DMSO/PPIX/PLGA microspheres alone caused only sublethal cytotoxicity to the cancer cells. Upon x-ray irradiation, the LaF3:Ce(3+)/DMSO/PPIX/PLGA microspheres induced oxidative stress, mitochondrial damage and DNA fragmentation on prostate cancer cells (PC3). DISCUSSION: The results indicate that x-rays can activate LaF3:Ce(3+) and PPIX nanocomposites, which can be a novel method for cancer destruction.

Enhancement of biophoton emission of prostate cancer cells by Ag nanoparticles.

Ultraweak intrinsic bioluminescence of cancer cell is a noninvasive method of assessing bioenergetic status of the investigated cells. This weak biophoton emission generated by prostate cancer cells (PC3) was measured in the presence of Ag nanoparticles and its correlation with singlet oxygen production was investigated. The comparison between nanoparticles concentration, bioluminescence intensity, and cell survival showed that Ag nanoparticles do not significantly affect cell survival at used concentration but they increase cell bioluminescent processes. It was also confirmed that singlet oxygen contributes to biophoton emission, that Ag nanoparticles increase this contribution, and that there are secondary mechanisms independent of singlet oxygen by which Ag nanoparticles contribute to increased cellular bioluminescence, possibly through plasmon resonance enhancement of intrinsic fluorescence.

Local field enhanced Au/CuS nanocomposites as efficient photothermal transducer agents for cancer treatment.

Photothermal therapy (PTT) for cancer treatment is the use of heat between 41 degrees C and 45 degrees C to damage cancer cells. As a new type of transducer agent for PPT of cancer, CuS nanoparticles have several advantages over gold nanostructures. The most favorable features are the low cost, simple and easy preparation, and small size for targeting. However, the CuS nanoparticle PTT efficacy needs to be improved for practical applications. In this study, the CuS nano-PTT efficiency was enhanced via the local field enhancement from Au nanoparticle surface plasmon coupling. The results show that absorbance of CuS nanoparticles in Au/CuS nanocomposites is enhanced about 2.2 times by Au nanoparticle surface plasmon coupling. Consequently, the PTT efficacy is enhanced and a power of 0.2 W/cm2 with a 980 nm laser was sufficient for Au/CuS nano-PTT activation. We have demonstrated for the first time that surface plasmon coupling can be used to enhance CuS nanoparticle PTT for cancer treatment.

Formation mechanism and characterization of black silicon surface by a single-step wet-chemical process.

We report a simple single-step etching method for formation of black surface on silicon wafer by using HAuCl4-HF-H2O2 etching solution, in which catalytic Au particles were deposited in situ. The black surface suppresses the reflectivity in a wide spectral region. The formation mechanism involved has been discussed.

Luminescence of lanthanide-dimethyl sulfoxide compound solutions.

Dimethyl sulfoxide (DMSO) has the ability to penetrate living tissues without causing significant damage. Of foremost importance to our understanding of the possible functions of DMSO in biological systems is its ability to replace some of the water molecules associated with the cellular constituents or to affect the structure of the omnipresent water. Luminescence probes have been widely used for biological studies such as labeling, imaging, and detection. Luminescence probes formed in DMSO may find new applications. Here luminescence compounds formed by refluxing lanthanide nitrates of Ce, La, Tb, Yb, Nd, Gd, and Eu in DMSO are reported and their luminescence properties investigated. On the basis of their luminescence spectral properties, the compounds can be classified into four classes. For compounds I with Yb, Ce, and La, the excitation and emission spectra are very broad and their excitation or emission peaks are shifted to longer wavelengths when the monitored emission or excitation wavelength is longer. For compounds II with Gd and Nd, both the excitation and emission spectra are very broad but their emission wavelengths change little at different excitation wavelengths. For Tb-DMSO as compound III, both the typical emissions from the f-f transitions of Tb(3+) and a broad emission at 445 nm are observed. At low reaction temperatures, the f-f emissions are dominant, while at high reaction temperatures such as 180 °C, the broad emission at 445 nm is dominant. For compound IV, Eu-DMSO, the dominant emissions are from the f-f transitions of Eu(3+) and only a weak broad emission is observed, which is likely from the d-f transition of Eu(2+) rather than from metal-to-ligand charge transfer states.

Interaction of porphyrins with CdTe quantum dots.

Porphyrins may be used as photosensitizers for photodynamic therapy, photocatalysts for organic pollutant dissociation, agents for medical imaging and diagnostics, applications in luminescence and electronics. The detection of porphyrins is significantly important and here the interaction of protoporphyrin-IX (PPIX) with CdTe quantum dots was studied. It was observed that the luminescence of CdTe quantum dots was quenched dramatically in the presence of PPIX. When CdTe quantum dots were embedded into silica layers, almost no quenching by PPIX was observed. This indicates that PPIX may interact and alter CdTe quantum dots and thus quench their luminescence. The oxidation of the stabilizers such as thioglycolic acid (TGA) as well as the nanoparticles by the singlet oxygen generated from PPIX is most likely responsible for the luminescence quenching. The quenching of quantum dot luminescence by porphyrins may provide a new method for photosensitizer detection.

Nonlinear enhancement of spontaneous biophoton emission of sweet potato by silver nanoparticles.

Ultraweak biophoton emission of cutting-injured sweet potato is enhanced by the incubation with Ag nanoparticles in a nonlinear way. The late peak of the emission after the cutting injury is amplified as much as 15 times, while only little amplification was identified for the emission measured immediately after the cutting. The effect requires the presence of nutritive media to support the active metabolic processes and is also affected by the timing of the addition of the Ag nanoparticles. Proposed mechanisms of reactive oxygen species generation and energy resonance transfer are discussed.

Folic acid-CdTe quantum dot conjugates and their applications for cancer cell targeting.

In this study, we report the preparation, luminescence, and targeting properties of folic acid-CdTe quantum dot conjugates. Water-soluble CdTe quantum dots were synthesized and conjugated with folic acid using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-N-hydroxysuccinimide chemistry. The influence of folic acid on the luminescence properties of CdTe quantum dots was investigated, and no energy transfer between them was observed. To investigate the efficiency of folic acid-CdTe nanoconjugates for tumor targeting, pure CdTe quantum dots and folic acid-coated CdTe quantum dots were incubated with human nasopharyngeal epidermal carcinoma cell line with positive expressing folic acid receptors (KB cells) and lung cancer cells without expression of folic acid receptors (A549 cells). For the cancer cells with positive folate receptors (KB cells), the uptake for CdTe quantum dots is very low, but for folic acid-CdTe nanoconjugates, the uptake is very high. For the lung cancer cells without folate receptors (A549 cells), the uptake for folic acid-CdTe nanoconjugates is also very low. The results indicate that folic acid is an effective targeting molecule for tumor cells with overexpressed folate receptors.

Quantum events of biophoton emission associated with complementary and alternative medicine therapies: a descriptive pilot study.

INTRODUCTION: Biophoton emission (BPE) is a quantum event characterized by a relatively stable but ultralow- rate emission of visible photons from living organisms. It has been associated with high energy processes such as: cell metabolism, growth, phagocytosis, neural activity, and oxidative stress. BPE has also been suggested to reflect the organism's global state of health as well as the response to stimulation including therapeutic interventions. If BPE changes occur as a result of various complementary and alternative medical interventions, this could prove useful to monitor both the patient's response to a specific treatment and global changes in their health status. This descriptive study attempts to identify BPE changes associated with three different chiropractic techniques that use different energetic approaches: mechanical, gravitational, and bioenergetic. MATERIALS AND METHODS: The BPE was measured at the neck and/or the lower back of 3 asymptomatic adult male volunteers. The measurements were made before and after different chiropractic interventions. The treatment techniques included a high velocity joint manipulation with the aid of a drop table, Sacro-Occipital Technique, and Bio-Energetic Synchronization Technique. Enough time was allotted for measurements in order to differentiate between natural fluctuation of the BPE and the changes induced by the interventions. RESULTS: All techniques induced small (up to 20%) but statistically significant changes (p < 0.05 in one case, p < 0.001 in the other two) in the BPE. Each technique demonstrated a different pattern of BPE change that may be specific to the technique. CONCLUSION: The intensity of BPE is a noninvasive indicator of the health of the human body and is significantly altered in different ways by chiropractic interventions. Future research is necessary to explore more features of BPE and its utility as an indicator of health, as well as the theoretical and clinical significance of these findings.