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Ferroptosis is an iron-dependent oxidative cell death with accumulation of lipid peroxidation and abnormal morphology of mitochondria. Although previous studies have shown that ferroptosis inducers have therapeutic potentials in several treatment-naive and drug-resistant cancer types, lacking systematic analysis of the ferroptosis sensitivity in different cancer types makes it difficult to know which cancer type is suitable for clinical usage and critical regulator determining the ferroptosis sensitivity during cancer progression is still not clear. In this study, colon cancer was identified as one of the ferroptosis-insensitive cancer types by dry and wet bench analyses. Importantly, our large-scale analysis also showed that NUDT16L1 was a novel ferroptosis repressor and overexpressed in colon cancer clinical specimens. Similar findings are also observed in the chemical-induced and genetic mouse models of colon cancer. Furthermore, NUDT16L1 loss-of-function and gain-of-function cell models and its conditional knock-in and knock-out mouse models are used to prove its crucial role in the development of colon cancer. In addition, loss of NUDT16L1 induced several key ferroptosis characteristics and impairment of mitochondrial functions while its restoration attenuated those phenomena in colon cancer cells. Mechanistically, our RNA-Seq and RIP-Seq analyses shown that NUDT16L1 directly interacted and positively regulated several crucial negative regulators of ferroptosis. More interestingly, loss of NUDT16L1 not only restores the sensitivity of ferroptosis inducer but also impairs the function of mitochondria. Finally, a specific NUDT16L1 inhibitor was shown to not only repress colon cancer growth in vitro and in vivo but also induce the ferroptosis in colon cancer. In conclusion, this is the first study to demonstrate that overexpression of NUDT16L1 promotes colon cancer progression by inhibition of ferroptosis and maintenance proper function of mitochondria. Furthermore, specific NUDT16L1 inhibitor might be a promising therapeutic strategy for colon cancer patient in the future. Citation Format: Yi-Syuan Lin, Ya-Chuan Tsai, Chia-Jung Li, Tzu-Tang Wei, Ya-Na Wu, Shang-Rung Wu, Shin-Chin Lin, Shaw-Jenq Tsai, Shih-Chieh Lin. NUDT16L1 promotes colon cancer progression via inhibition of ferroptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1372.

In this study, we demonstrated that zero-valent iron (ZVI), which is widely used to remediate environmental contamination through the production of high-energy reactive oxygen species (ROS), exhibited differential cytotoxicity in cancerous cells and nonmalignant cells. Nanoparticles (NPs) with different shells exhibited distinct potencies against cancerous cells, which depended on their iron-to-oxygen ratios. Silver-coated ZVI NPs (ZVI@Ag) had the highest potency among synthesized ZVI NPs, and they simultaneously exhibited adequate biocompatibility with nonmalignant keratinocytes. The assessment of the intracellular dynamics of iron species revealed that the uptake of ZVI@Ag was similar between cancerous cells and nonmalignant cells during the first 2 h; however, only cancerous cells rapidly converted NPs into iron ions and generated large amounts of intracellular ROS, which was followed by apoptosis and autophagy induction. The aforementioned processes were prevented in the presence of iron ion chelators or by preoxidizing NPs before administration. Neutralization of lysosomal pH effectively reduced ZVI@Ag NP-induced programmed cell death. In the xenograft mouse model, cancer growth was significantly inhibited by a single dose of systematically administered NPs without significant weight loss in animals.

Posttranscriptional modifications in RNA have been considered to contribute to disease pathogenesis and tumor progression. NOL1/NOP2/Sun domain family member 2 (NSUN2) is an RNA methyltransferase that promotes tumor progression in several cancers. Pancreatic cancer relapse inevitably occurs even in cases where primary tumors have been successfully treated. Associations of cancer progression due to reprogramming of the cancer methyl-metabolome and the cancer genome have been noted, but the effect of base modifications, namely 5-methylcytosine (m

Group A streptococcus (GAS) is an important human pathogen which can cause fatal diseases after invasion into the bloodstream. Although antibiotics and immune surveillance are the main defenses against GAS infection, GAS utilizes internalization into cells as a major immune evasion strategy. Our previous findings revealed that light chain 3 (LC3)-associated single membrane GAS-containing vacuoles in endothelial cells are compromised for bacterial clearance due to insufficient acidification after fusion with lysosomes. However, the characteristics and the activation mechanisms of these LC3-positive compartments are still largely unknown. In the present study, we demonstrated that the LC3-positive GAS is surrounded by single membrane and colocalizes with NADPH oxidase 2 (NOX2) complex but without ULK1, which are characteristics of LC3-associated phagocytosis (LAP). Inhibition of NOX2 or reactive oxygen species (ROS) significantly reduces GAS multiplication and enhances autolysosome acidification in endothelial cells through converting LAP to conventional xenophagy, which is revealed by enhancement of ULK1 recruitment, attenuation of p70s6k phosphorylation, and formation of the isolation membrane. We also clarify that the inactivation of mTORC1, which is the initiation signal of autophagy, is inhibited by NOX2- and ROS-activated phosphatidylinositol 3-kinase (PI3K)/AKT and MEK/extracellular signal-regulated kinase (ERK) pathways. In addition, streptolysin O (SLO) of GAS is identified as a crucial inducer of ROS for β1 integrin-mediated LAP induction. After downregulation of β1 integrin, GAS multiplication is reduced, accompanied with LAP inhibition and xenophagy induction. These results demonstrate that GAS infection preferentially induces ineffective LAP to evade xenophagic killing in endothelial cells through the SLO/β1 integrin/NOX2/ROS pathway.

Clostridioides difficile, a spore-forming bacterium, is a nosocomial infectious pathogen which can be found in animals as well. Although various antibiotics and disinfectants were developed, C. difficile infection (CDI) remains a serious health problem. C. difficile spores have complex structures and dormant characteristics that contribute to their resistance to harsh environments, successful transmission and recurrence. C. difficile spores can germinate quickly after being exposed to bile acid and co-germinant in a suitable environment. The vegetative cells produce endospores, and the mature spores are released from the hosts for dissemination of the pathogen. Therefore, concurrent elimination of C. difficile vegetative cells and inhibition of spore germination is essential for effective control of CDI. This review focused on the molecular pathogenesis of CDI and new trends in targeting both spores and vegetative cells of this pathogen, as well as the potential contribution of nanotechnologies for the effective management of CDI.

Our previous reports showed that the LC3-associated GAS-containing single membrane vacuoles are inefficient for bacterial clearance in endothelial cells, which may result in bacteremia. However, the characteristics and the induction mechanisms of these LC3-positive vacuoles are still largely unknown. Here we provide the first evidence that these LC3-positive GAS-containing single membrane compartments appear to be LAPosomes, which are induced by NOX2 and ROS. Through NOX2- and ROS-mediated signaling, GAS preferentially induces LAP and inhibits bacteriostatic xenophagy in endothelial cells. We also provide the first demonstration that β1 integrin acts as the receptor for LAP induction through GAS-produced SLO stimulation in endothelial cells. Our findings reveal the underlying mechanisms of LAP induction and autophagy evasion for GAS multiplication in endothelial cells., Group A streptococcus (GAS) is an important human pathogen which can cause fatal diseases after invasion into the bloodstream. Although antibiotics and immune surveillance are the main defenses against GAS infection, GAS utilizes internalization into cells as a major immune evasion strategy. Our previous findings revealed that light chain 3 (LC3)-associated single membrane GAS-containing vacuoles in endothelial cells are compromised for bacterial clearance due to insufficient acidification after fusion with lysosomes. However, the characteristics and the activation mechanisms of these LC3-positive compartments are still largely unknown. In the present study, we demonstrated that the LC3-positive GAS is surrounded by single membrane and colocalizes with NADPH oxidase 2 (NOX2) complex but without ULK1, which are characteristics of LC3-associated phagocytosis (LAP). Inhibition of NOX2 or reactive oxygen species (ROS) significantly reduces GAS multiplication and enhances autolysosome acidification in endothelial cells through converting LAP to conventional xenophagy, which is revealed by enhancement of ULK1 recruitment, attenuation of p70s6k phosphorylation, and formation of the isolation membrane. We also clarify that the inactivation of mTORC1, which is the initiation signal of autophagy, is inhibited by NOX2- and ROS-activated phosphatidylinositol 3-kinase (PI3K)/AKT and MEK/extracellular signal-regulated kinase (ERK) pathways. In addition, streptolysin O (SLO) of GAS is identified as a crucial inducer of ROS for β1 integrin-mediated LAP induction. After downregulation of β1 integrin, GAS multiplication is reduced, accompanied with LAP inhibition and xenophagy induction. These results demonstrate that GAS infection preferentially induces ineffective LAP to evade xenophagic killing in endothelial cells through the SLO/β1 integrin/NOX2/ROS pathway.

Clinical management of Clostridium difficile infection is still far from satisfactory as bacterial spores are resistant to many chemical agents and physical treatments. Certain types of nanoparticles have been demonstrated to exhibit anti-microbial efficacy even in multi-drug resistance bacteria. However, most of these studies failed to show biocompatibility to the mammalian host cells and no study has revealed in vivo efficacy in C. difficile infection animal models. The spores treated with 500 µg/mL Fe3-δO4 nanoparticles for 20 minutes, 64% of the spores were inhibited from transforming into vegetative cells, which was close to the results of the sodium hypochlorite-treated positive control. By cryo-electron micro-tomography, we demonstrated that Fe3-δO4 nanoparticles bind on spore surfaces and reduce the dipicolinic acid (DPA) released by the spores. In a C. difficile infection animal model, the inflammatory level triple decreased in mice with colonic C. difficile spores treated with Fe3-δO4 nanoparticles. Histopathological analysis showed a decreased intense neutrophil accumulation in the colon tissue of the Fe3-δO4 nanoparticle-treated mice. Fe3-δO4 nanoparticles, which had no influence on gut microbiota and apparent side effects in vivo, were efficacious inhibitors of C. difficile spore germination by attacking its surface and might become clinically feasible for prophylaxis and therapy.

How to improve the selectivity and efficacy of anticancer agents and to reduce side effects has always been a big challenge in clinical cancer therapy. Chemotherapeutic agents are usually toxic to both cancer and normal tissues, thus rendering compromised overall clinical outcome. Here we developed zero-valent iron nanoparticles (ZVI NPs) that exhibited selectivity toward higher toxicity to most cancerous cells thus opening a new era of anti-cancer therapy or adjuvant therapy through a novel molecular signaling pathway. We used head-and-neck cancer (HNC) cells and ovarian cancer (OVCA) cells to test the anti-cancer properties of ZVI NPs. The ZVI NPs served as a strong reactive oxygen species (ROS) inducer and caused irreversible mitochondria membrane potential lost in sensitive cancer cells that lead to cancer cell autophagy and growth suppression, while not significantly affect normal cell population. Further, the cytotoxicity of the ZVI NPs is highly depended on its redox state as oxidation of the NPs upon aging reduced their cytotoxic potency. In vivo study revealed a dose dependent tumor size reduction in tumor-bearing mice model without significant weight loss and pathological signs. These results suggest that ZVI NPs may serve as a new class of anticancer agent for a wide spectra of neoplastic diseases.

To evaluate the iron ion release profile of zero-valent iron (ZVI)-based nanoparticles (NPs) and their relationship with lysosomes in cancer cells, silica and mesoporous silica-coated ZVI NPs (denoted as ZVI@SiO2 and ZVI@mSiO2) were synthesized and characterized for the following study of cytotoxicity, intracellular iron ion release, and their underlying mechanisms. ZVI@mSiO2 NPs showed higher cytotoxicity than ZVI@SiO2 NPs in the OEC-M1 oral cancer cell line. In addition, internalized ZVI@mSiO2 NPs deformed into hollow and void structures within the cells after a 24-h treatment, but ZVI@SiO2 NPs remained intact after internalization. The intracellular iron ion release profile was also accordant with the structural deformation of ZVI@mSiO2 NPs. Burst iron ion release occurred in ZVI@mSiO2-treated cells within an hour with increased lysosome membrane permeability, which induced massive reactive oxygen species generation followed by necrotic and apoptotic cell death. Furthermore, inhibition of endosome&ndash, lysosome system acidification successfully compromised burst iron ion release, thereby reversing the cell fate. An in vivo test also showed a promising anticancer effect of ZVI@mSiO2 NPs without significant weight loss. In conclusion, we demonstrated the anticancer property of ZVI@mSiO2 NPs as well as the iron ion release profile in time course within cells, which is highly associated with the surface coating of ZVI NPs and lysosomal acidification.

Teeth are key to understanding the feeding ecology of both extant and extinct vertebrates. Recent studies have highlighted the previously unrecognized complexity of dinosaur dentitions and how specific tooth tissues and tooth shapes differ between taxa with different diets. However, it is unknown how the ultrastructure of these tooth tissues contributes to the differences in feeding style between taxa. In this study, we use third harmonic generation microscopy and scanning electron microscopy to examine the ultrastructure of the dentine in herbivorous and carnivorous dinosaurs to understand how the structure of this tissue contributes to the overall utility of the tooth. Morphometric analyses of dentinal tubule diameter, density and branching rates reveal a strong signal for dietary preferences, with herbivorous saurischian and ornithischian dinosaurs consistently having higher dentinal tubule density than their carnivorous relatives. We hypothesize that this relates to the hardness of the dentine, where herbivorous taxa have dentine that is more resistant to breakage and wear at the dentine–enamel junction than carnivorous taxa. This study advocates the detailed study of dentine and the use of advanced microscopy techniques to understand the evolution of dentition and feeding ecology in extinct vertebrates.

Class I fungal hydrophobins are small surface-active proteins that self-assemble to form amphipathic monolayers composed of amyloid-like rodlets. The monolayers are extremely robust and can adsorb onto both hydrophobic and hydrophilic surfaces to reverse their wettability. This adherence is particularly strong for hydrophobic materials. In this report, we show that the class I hydrophobins EAS and HYD3 can self-assemble to form a single-molecule thick coating on a range of nanomaterials, including single-walled carbon nanotubes (SWCNTs), graphene sheets, highly oriented pyrolytic graphite, and mica. Moreover, coating by class I hydrophobin results in a stable, dispersed preparation of SWCNTs in aqueous solutions. No cytotoxicity is detected when hydrophobin or hydrophobin-coated SWCNTs are incubated with Caco-2 cells in vitro. In addition, we are able to specifically introduce covalently linked chemical moieties to the hydrophilic side of the rodlet monolayer. Hence, class I hydrophobins provide a simple and effective strategy for controlling the surfaces of a range of materials at a molecular level and exhibit strong potential for biomedical applications. © 2012 Wiley Periodicals, Inc.

Finding a cancer-selective drug that avoids damaging healthy cells and organs is a holy grail in medical research. In our previous studies, gold-coated iron (Fe@Au) nanoparticles showed cancer selective anti-cancer properties in vitro and in vivo but were found to gradually lose that activity with storage or “ageing„. To determine the reasons for this diminished anti-cancer activity, we examined Fe@Au nanoparticles at different preparation and storage stages by means of transmission electron microscopy combined with and energy-dispersive X-ray spectroscopy, along with X-ray diffraction analysis and cell viability tests. We found that dried and reconstituted Fe@Au nanoparticles, or Fe@Au nanoparticles within cells, decompose into irregular fragments of γ-F2O3 and agglomerated gold clumps. These changes cause the loss of the particles’ anti-cancer effects. However, we identified that the anti-cancer properties of Fe@Au nanoparticles can be well preserved under argon or, better still, liquid nitrogen storage for six months and at least one year, respectively.

Gold nanoparticles have been developed for the photoacoustic imaging, delivery of genes and laser induced photothermal therapy. In this study, we have developed oligonucleotide conjugated gold nanoparticles as the carrier for simultaneous DNA and anti-cancer nucleoside delivery. The polynucleotide-nanoparticle complex presented higher capacity in carrying 5-FU anti-cancer compounds than the original gold particles. The hydrodynamic size of the gold nanoparticles increased from 25 to 35 nm with an increase in the negative surface charge from -9.58 to 21.66 mV after polynucleotide conjugation and drug loading. A positive association between environmental pH and drug release was observed in PBS, which implied their potential use in the controlled localized drug release in the lower GI tract. The MTT assay revealed dose dependent cytotoxicity to colon cancer cell line than free compounds. These results suggest the potential use of this new polynucleotide-gold nanoparticles complex as the environmental controlled anti-cancer nanocapsule, especially suitable for per oral colon cancer chemotherapy.

Gold nanoparticles with carbohydrate ligands attached on their surface have been synthesized and characterized with various techniques. The new nanoparticle conjugates have shown great potentials as a contrast agent for opto-acoustic imaging. Hemocompatibility measurements of human blood for the carbohydrate-gold nanoparticles have shown that the conjugates are feasible for in vivo testing. Preliminary quantitative flow measurements using the conjugates were also studied in this work based on the indicator-dilution theory. In vitro phantom experiments were designed and conducted, and results were discussed.

Fossil teeth are primary tools in the study of vertebrate evolution, but standard imaging modalities have not been capable of providing high-quality images in dentin, the main component of teeth, owing to small refractive index differences in the fossilized dentin. Our first attempt to use third-harmonic generation (THG) microscopy in fossil teeth has yielded significant submicrometer level anatomy, with an unexpectedly strong signal contrasting fossilized tubules from the surrounding dentin. Comparison between fossilized and extant teeth of crocodilians reveals a consistent evolutionary signature through time, indicating the great significance of THG microscopy in the evolutionary studies of dental anatomy in fossil teeth.

A new γ-Fe2O3 MION ferrofluid has been developed with a salt-assisted solid-state reaction. Characterizations show that the ferrofluid is composed of maghemite nanoparticles with a mean diameter of 2.7 nm. Though the nanoparticles are ultrafine, they are well crystallized, with a saturation magnetization value of 34.7 emu g−1, making them suitable for MRI applications. In spite of the absence of any surfactant, the ferrofluid can be stable for more than 6 months. An in vitro cytotoxicity test revealed good biocompatibility of the maghemite nanoparticles, suggesting that they may be further explored for biomedical applications. NMR measurements revealed significantly reduced water proton relaxation times T1 and T2. The MR images of the nanoparticles in aqueous dispersion were investigated using a 3 T clinical MR imager. These preliminary experiments have demonstrated the potential of the as-synthesized ultrafine, cap-free maghemite MIONs in functional molecular imaging for biomedical research and clinical diagnosis.

Clear 3D visualization in fossilized dentinal tissues was first discovered with extremely strong contrast by means of third harmonic generation microscopy, providing a novel approach to study the dental evolution of ancient vertebrates (dinosaurs) noninvasively.

The demand for functional imaging in clinical medicine is comprehensive. Although the gold standard for the functional imaging of human bones in clinical settings is still radionuclide-based imaging modalities, nonionizing noninvasive imaging technology in small animals has greatly advanced in recent decades, especially the diffuse optical imaging to which Britton Chance made tremendous contributions. The evolution of imaging probes, instruments, and computation has facilitated exploration in the complicated biomedical research field by allowing longitudinal observation of molecular events in live cells and animals. These research-imaging tools are being used for clinical applications in various specialties, such as oncology, neuroscience, and dermatology. The Bone, a deeply located mineralized tissue, presents a challenge for noninvasive functional imaging in humans. Using nanoparticles (NP) with multiple favorable properties as bioimaging probes has provided orthopedics an opportunity to benefit from these noninvasive bone-imaging techniques. This review highlights the historical evolution of radionuclide-based imaging, computed tomography, positron emission tomography, and magnetic resonance imaging, diffuse optics–enabled in vivo technologies, vibrational spectroscopic imaging, and a greater potential for using NPs for biomedical imaging.

A comprehensive totally aqueous phase synthesis of nickel-nitrilotriacetate (Ni-NTA) modified superparamagnetic Fe(3)O(4) nanoparticles is presented. The Fe(3)O(4)-NTA-Ni nanoparticles are able to perform efficient and specific purification of 6-His tagged proteins from crude cell lysates, as evidenced by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. The average binding capacity, as demonstrated by streptopain (M(W) 42 kDa), is 0.23 mg/mg (protein/Fe(3)O(4)-NTA-Ni). Considering the high affinity and specificity of the binding between hexahistidine motif and Ni-NTA, Ni-NTA modified nanoparticles could act as a module to carry 6-His tagged proteins on the particle surface with molecular orientation control, since only the 6-His domain could be attached. These modularly designed functional nanoparticles enhance cancer cell targeting, as supported by the in vitro receptor mediated targeting assay using RGD-4C-6-His fusion peptide. The nanoparticles show no significant hemolysis for human blood and could be investigated further for their in vivo functional imaging applications.

Gold-coated iron nanoparticles (NPs) selectively and significantly (P0.0001) inhibit proliferation of oral- and colorectal-cancer cells in vitro at doses as low as 5 μg/mL, but have little adverse effect on normal healthy control cells. The particle treatment caused delay in cell-cycle progression, especially in the S-phase. There was no significant difference in the NP uptake between cancer and control cells, and cytotoxicity resulted primarily from the iron core, before oxidation, rather than from the Fe ions released from the core. In contrast with magnetic NPs that usually serve as drug carriers, diagnostic probes or hyperthermia media, the iron, before oxidation, in the NPs selectively suppressed cancer cell growth and left healthy control cells unaffected in vitro and in vivo. This novel nanomaterial holds great promise as a therapeutic tool in nanomedicine.Gold-coated iron nanoparticles (NPs) selectively suppressed squamous cell carcinoma (SCC) and colorectal cancer (CRC) cell growth, but left healthy control cells unaffected both in vitro and in vivo. The particles were equally uptaken by all cells, but delayed cell progression only for cancer cells. The origin is related to the iron core: neither iron ions nor the oxidized NPs have the same outcome.

The wind stroke is a common syndrome in clinical disease; the physicians of past generations accumulated much experience in long-term clinical practice and left abundant literature. Looking from this literature, the physicians of past generations had different cognitions of the wind stroke, especially the concept of wind stroke. The connotation of wind stroke differed at different stages, going through a gradually changing process from exogenous disease, true wind stroke, apoplectic wind stroke to cerebral apoplexy.

Ultrasound imaging is a relatively low cost, portable and non-invasive medical imaging modality for the diagnosis of a wide spectrum of diseases. Molecular imaging of diseases provide valuable information for improved disease diagnosis and management and has been developed to integrate into various medical imaging platform. However, no molecular probes has been developed for ultrasound imaging to date. In this study, we synthesized gold nano rod (AuNRs) with controllable aspect ratio as the core of molecular probe. The AuNR was modified with poly-ethylene glycol (PEG) and monocolonal antibody specific for the target biomolecules such as Her-2, CXCR4, EGFR in this research. The molecular photoacoustic ultrasonography. The AuNR probe exhibit surface plasmonic resonance frequency (SPR) proportional to their aspect ratio. Two type of AuNR with SPR at 785 nm and 1000 nm, respectively, were synthesized. The SPR spectra fall into NIR range of biological optical window and thus enabled better tissue penetration of the laser light. Interaction of AuNRs with laser irradiation was able to generate acoustic wave for image reconstruction and precision dynamic measurement of local fluid flow. In vitro study demonstrated a significant photoacoustic molecular imaging of Her-2 in the wild type cancer cells compared to the gene knock down cells mediated by stable transfection of RNAi. The use of molecular probes with different peak SPR frequencies enabled a differential molecular diagnosis of expression level of EGFR or Her2 oncogenes in two cell line models by modulation of laser wavelength. Molecular imaging of cancer bearing animals also obtained primary success with an augmentation in signal intensity from 3 db to 5 db by using multiple cocktail molecular probes. In addition, AuNR was found to absorb laser light with corresponding SPR frequency to generate local heat at nanometer scale range, which could be applied for precision hyperthermia therapy. AuNRs conjugated HER-2 antibodies successfully target tumor cells of high expression level and induced cancer cell death upon laser irradiation while spare the control cell line of low expression level. A laser wave length guided selective targeting cancer cell therapy was demonstrated using two types of molecular probes (anti-EGFR and anti-Her2) with different peak SPR and four different cancer cell lines. Combined cocktail probes targeting to the same cancer cell significantly improve therapeutic efficacy. In conclusion, a novel AuNR-molecular probe system that combined the power of photoacoustic molecular imaging and targeting therapy in one was developed and demonstrated to be effective. Future preclinical and clinical evaluation is warranted.

In order to study the intestinal absorption behaviors of three active constituents, columbianetin acetate, osthole and columbianadin in Radix Angelicae Pubescentis extracts, in situ rat single pass intestine perfusion (SPIP) was carried out by the perfusion solution of the extract I containing less than 10% total coumarins. The absorption of extract II containing more than 60% total coumarins was compared with that of extract I by rat colon SPIP to elucidate the influence on absorption of the different coumarin content extracts of the Chinese traditional medicine. The samples of the perfusion solution were collected in certain intervals. The concentrations of three active components in the perfusion samples were determined by HPLC method. The results demonstrated that the absorption rate constants (Ka) or apparent permeability coefficients (Papp) of columbianetin acetate, osthole and columbianadin from extract I had no significant difference among concentration ranges of 62-555 microg x mL(-1), 101-887 microg x mL(-1), 19-186 microg x mL(-1), respectively. The absorption quantity of three components was proportional to its concentration respectively and the saturate absorption phenomena were not observed. This suggested that the absorption of columbianetin acetate, osthole and columbianadin showed the passive diffusion process. Three components could be absorbed in whole intestinal sections. The Ka and Papp of three components all showed colonduodenumjejunumileum in four different regions of rat intestine. At colon, Ka and P app were significant different from the others. The Ka or Papp of three components from the extract I was significantly more than that of same components from extract II. The extract I redounded to increase the absorption of three active components.

Silicon-On-Insulator (SOI) based nanowire field-effect-transistors were used to detect the molecular charges on the wire surface. The sensors hold great potential for various biomedical applications (Li et al., 2004) due to their intrinsic advantages in many aspects including high sensitivity with minimal requirement of the target molecules, capability for multiplex parallel processing, and requiring no tedious sample labeling process. The variations of the molecular charges can be detected by measuring the changes of the wire conductance. In this work, we show that when incorporated with surface APTES molecules, the SOI-based silicon nanowires can act as a detector for DNA-hybridization. The high charge sensitivity of the nanowires allowed real time detection of hybridization of ssDNA with lengths as short as 15 mer, and with high degree of specificity. Details about device and microfluidic channel fabrication processes, and procedures for surface modification, DNA immobilization are provided in the following sections.

Cancer cells presented altered surface molecules to encourage their growth and metastasis. Expression of oncogeneic surface molecules also play important roles in the prediction of clinical outcome and treatment response of anti-cancer drugs. It is thus conceivable that imaging of cancer lesions while simultaneously obtaining their pathogenic information at molecular level of as many oncogenic proteins as possible is of great clinical significance. Gold nanoparticles have been used as a contrast agent for photoacoustic imaging. In addition, gold nanoparticles can be bioconjugated to probe certain molecular processes. An intriguing property of gold nanoparticles is its ability to tailor its optical properties. For example, size effects on the surface plasmon absorption of spherical gold nanoparticles have shown that the peak optical absorption red-shifts with the increasing particle size. In addition, the optical absorption spectrum of cylindrical gold nanoparticles (i.e., gold nanorods) exhibits a strong absorption band that is directly related to the aspect ratio. With these unique characteristics, selective targeting can be achieved in photoacoustic molecular imaging. Specifically, gold nanorods with different aspect ratios can be bioconjugated to different antibodies. Multiple targeting and simultaneous detection can then be achieved by using laser irradiation at the respective peak optical absorption wavelength. In this study, photoacoustic multiple targeting using gold nanorods is experimentally demonstrated. We have chosen Her2 and CXCR4 as our primary target molecule as Her2 expression is associated with growth characteristics and sensitivity to Herceptin chemotherapy. On the other hand, CXCR4 expression predict the organ-specific metastatic potential of the cancer cells for clinical intervention in advance. Monoclonal antibody (mAb) against Her2/neu was conjugated to nanorods with several different aspect ratios. The agarose gel is suitable for photoacoustic signal acquisition. A wavelength tunable Ti-Sapphire laser was used for laser irradiation and a 1 MHz ultrasound transducer was used for acoustic detection. The optical wavelength of the laser was tuned between 800 nm and 940 nm, corresponding to gold nanorods of an aspect ratio ranging from 3.7 to 5.9. The results clearly show the potential of photoacoustic molecular imaging with multiple targeting in revealing different oncogene expression levels of the cancer cells.

Spectral dependent values of the third-harmonic-generation susceptibility chi(3)(3omega:omega,omega,omega) of Ag-nanoparticles have been successfully determined. When the third-harmonic-generation wavelength coincides with the Ag-nanoparticlespsila plasmon-resonant frequency, strong chi(3)(3omega:omega,omega,omega) enhancement is experimentally proved for the first time.

In the current study, amine surface modified iron-oxide nanoparticles of 6 nm diameter without polymer coating were fabricated in an aqueous solution by organic acid modification as an adherent following chemical coprecipitation. Structure and the superparamagnetic property of magnetite nanoparticles were characterized by selected area electron diffraction (SAED) and superconducting quantum interference measurement device (SQUID). X-ray photoelectron spectrometer (XPS) and zeta potential measurements revealed cationic surface mostly decorated with terminal -NH(3)(+). This feature enables them to function as a magnetic carrier for nucleotides via electrostatic interaction. In addition, Fe(3)O(4)/trypsin conjugates with well-preserved functional activity was demonstrated. The nanoparticles displayed excellent in vitro biocompatibility. The NMR and the in vitro MRI measurements showed significantly reduced water proton relaxation times of both T(1) and T(2). Significantly reduced T(2) and T(2)*-weighted signal intensity were observed in a 1.5 T clinical MR imager. In vivo imaging contrast effect showed a fast and prolonged inverse contrast effect in the liver that lasted for more than 1 week. In addition, it was found that the spherical Fe(3)O(4) assembled as rod-like configuration through an aging process in aqueous solution at room temperature. Interestingly, TEM observation of the liver tissue revealed the rod-like shape but not the spherical-type nanoparticles being taken up by the Kupffer cells 120 h after tail vein infusion. Combining these results, we have demonstrated the potential applications of the newly synthesized magnetite nanoparticles in a broad spectrum of biomedical applications.

We demonstrate molecular-specific third-harmonic-generation microscopy in cultured oral squamous cell carcinoma lines by using silver nano-particles as contrast agent. Through surface plasmon resonance enhancement, cancer cells are clearly identified with their molecular signature.

AIM: To characterise differences between three widely used colorectal cancer cell lines using ultrastructural selective staining for glycogen to determine variation in metastatic properties. METHODS: Transmission electron microscopy was used in this investigation to help identify intracellular structures and morphological features which are precursors of tumor invasion. In addition to morphological markers, we used selective staining of glycogen as a marker for neoplastic cellular proliferation and determined whether levels of glycogen change between the three different cell lines. RESULTS: Ultrastructural analysis revealed morphological differences between the cell lines, as well as differentiation into two sub-populations within each cell line. Caco-2 cells contained large glycogen deposits as well as showing the most obvious morphological changes between the two sub-populations. SW480 cells also contained large glycogen stores as well as deep cellular protrusions when grown on porous filter membranes. HT-29 cells had trace amounts of glycogen stores with few cellular projections into the filter pores and no tight junction formation. CONCLUSION: Morphology indicative of metastatic properties coincided with larger glycogen deposits, providing strong evidence for the use of selective staining to determine the neoplastic properties of cells.

The use of gold nanorods for photoacoustic molecular imaging in vivo with simultaneous multiple selective targeting is reported. The extravasation of multiple molecular probes is demonstrated, and used to probe molecular information of cancer cells. This technique allows molecular profiles representing tumor characteristics to be obtained and a heterogeneous population of cancer cells in a lesion to be determined. The results also show that the image contrast can be enhanced by using a mixture of different molecular probes. In this study, HER2, EGFR, and CXCR4 were chosen as the primary target molecules for examining two types of cancer cells, OECM1 and Cal27. OECM1 cells overexpressed HER2 but exhibited a low expression of EGFR, while Cal27 cells showed the opposite expression profile. Single and double targeting resulted in signal enhancements of up to 3 dB and up to 5 dB, respectively, and hence has potential in improving cancer diagnoses.