Image-Guided Precision Treatments.

Chemotherapy, radiotherapy, and surgery are traditional cancer treatments, which usually produce unpredictable side effects and potential risks to normal healthy organs/tissues. Thus, safe and reliable treatment strategies are urgently required for maximized therapeutic efficiency to lesions and minimized risks to healthy regions. To this end, molecular imaging is responsible to undertake a specific targeting therapy. Besides that, the image guidance as a precision visualized approach for real-time in situ evaluations as well as an intraoperational navigation approach has earned attractive attention in the past decade. Along with the rapid development of multifunctional micro-/nanobiomaterials, versatile cutting-edge and advanced therapy strategies (e.g., thermal therapy, dynamic therapy, gas therapy, etc.) have been achieved and greatly contributed to the image-guided precision treatments in every aspect. Therefore, this chapter aims to discuss about both traditional and advanced cancer treatments and especially to elucidate the important roles that visualized medicine has been playing in the image-guided precision treatments.

Imaging-Navigated Surgery.

It is vitally important to guide or navigate therapeutic proceedings with a direct and visual approach in order to carefully undertake precision medical manipulations and efficiently evaluate the treatments. Imaging-navigated surgery is one of the common and prevailing technologies to realize this target, and more importantly it merges visualized medicine into next-generation theranostic paradigms in modern medicine. Endoscopes, surgical robots, and nanorobots are three major domains in terms of imaging-navigated surgery. The history of endoscopy has seen upgraded developments since the early 1800s. In contrast, surgical robots have been widely used and investigated in recent years, and they came into clinical uses only in the past decades. Nanorobots which closely depend on innovated and multifunctional biomaterials are still in their infancy. All these imaging-navigated technologies show similar and apparent advantages such as minimal invasiveness, minimized pain, positive prognosis, and relatively expected recovery, which have greatly improved surgery efficiency and patients' life quality. Therefore, the imaging-navigated surgery will be discussed in this chapter, and advanced clinical and preclinical medical applications will also be demonstrated for a diverse readers and comprehensive understanding.

Functional micro/nanobubbles for ultrasound medicine and visualizable guidance.

Chemically functionalized gas-filled bubbles with a versatile micro/nano-sized scale have witnessed a long history of developments and emerging applications in disease diagnosis and treatments. In combination with ultrasound and image-guidance, micro/nanobubbles have been endowed with the capabilities of biomedical imaging, drug delivery, gene transfection and disease-oriented therapy. As an external stimulus, ultrasound (US)-mediated targeting treatments have been achieving unprecedented efficiency. Nowadays, US is playing a crucial role in visualizing biological/pathological changes in lives as a reliable imaging technique and a powerful therapeutic tool. This review retrospects the history of ultrasound, the chemistry of functionalized agents and summarizes recent advancements of functional micro/nanobubbles as US contrast agents in preclinical and transclinical research. Latest ultrasound-based treatment modalities in association with functional micro/nanobubbles have been highlighted as their great potentials for disease precision therapy. It is believed that these state-of-the-art micro/nanobubbles will become a booster for ultrasound medicine and visualizable guidance to serve future human healthcare in a more comprehensive and practical manner.

Single-molecule imaging reveals transforming growth factor-beta-induced type II receptor dimerization.

Transforming growth factor-beta (TGF-beta) elicits its signals through two transmembrane serine/threonine kinase receptors, type II (TbetaRII) and type I receptors. It is generally believed that the initial receptor dimerization is an essential event for receptor activation. However, previous studies suggested that TGF-beta signals by binding to the preexisting TbetaRII homodimer. Here, using single molecule microscopy to image green fluorescent protein (GFP)-labeled TbetaRII on the living cell surface, we demonstrated that the receptor could exist as monomers at the low expression level in resting cells and dimerize upon TGF-beta stimulation. This work reveals a model in which the activation of serine-threonine kinase receptors is also accomplished via dimerization of monomers, suggesting that receptor dimerization is a general mechanism for ligand-induced receptor activation.

Single-molecule study of lateral mobility of epidermal growth factor receptor 2/HER2 on activation.

The transmembrane protein HER2, a member of the epidermal growth factor receptor family of tyrosine kinase, plays important roles in many fundamental cellular processes as well as the pathogenesis of many cancers. In this work, we have applied the single-molecule fluorescence microscopic method to study lateral mobility change of HER2 on activation by imaging and tracking individual GFP-tagged HER2 molecules on the membrane of living cells. The single HER2 molecules displayed different diffusion rates and modes. It was interesting to find that the mobility of HER2 increased upon stimulation by heregulin beta1, the specific ligand of HER3. The faster diffusion was related to the tyrosine phosphorylation of HER2 or EGFR. The results provided new information for the understanding of HER2 activation and molecular mechanism of signal transduction through HER2/HER3 heterodimerization.

Conjugation of a water-soluble gadolinium endohedral fulleride with an antibody as a magnetic resonance imaging contrast agent.

Water-soluble gadofullerides exhibited high efficiency as magnetic resonance imaging (MRI) contrast agents. In this paper, we report the conjugation of the newly synthesized gadofulleride, Gd@C82O6(OH) 16(-)(NHCH2CH2COOH)8, with the antibody of green fluorescence protein (anti-GFP), as a model for "tumor targeted" imaging agents based on endohedral metallofullerenes. In this model system, the activity of the anti-GFP conjugate can be conveniently detected by green fluorescence protein (GFP), leading to in vitro experiments more direct and facile than those of tumor antibodies. Objective-type total internal reflection fluorescence microscopy revealed that each gadofulleride aggregate conjugated on average five anti-GFPs, and the activity of anti-GFPs was preserved after conjugation. In addition, the gadofulleride/antibody conjugate exhibited higher water proton relaxivity (12.0 mM (-1) s (-1)) than the parent gadofulleride aggregate (8.1 mM (-1) s (-1)) in phosphate buffered saline at 0.35 T, as also confirmed by T1-weighted images of phantoms. These observations clearly indicate that the synthesized gadofulleride/antibody conjugate not only has targeting potential, but also exhibits higher efficiency as an MRI contrast agent.

Single-molecule force spectroscopy study of interaction between transforming growth factor beta1 and its receptor in living cells.

Transforming growth factor beta1 (TGF-beta1) regulates many important cellular processes such as cell proliferation, differentiation, and apoptosis, etc. Its signaling is initiated by binding to and bringing together TGF-beta type II receptor (TbetaRII) and type I receptor (TbetaRI). However, it is not fully understood how the TGF-beta1 ligand-receptor interaction occurs in living cells and what is the molecular mechanism of the signaling complex TGF-beta1/TbetaRII/TbetaRI formation. In this study, we have investigated the interaction between TGF-beta1 and its receptors in living cells with single-molecule force spectroscopy for the first time. By positioning TGF-beta1-modified atomic force microscope (AFM) tips on the cells expressing fluorescent protein tagged TGF-beta receptors, the living-cell force measurement was realized with a combined fluorescence microscope and AFM. We found that coexpression of TbetaRI with TbetaRII enhanced the binding force of TGF-beta1 with its receptors, whereas the expressed TbetaRI itself exhibited no binding affinity to TGF-beta1. Moreover, the unbinding dynamics of TGF-beta1/TbetaRII and TGF-beta1/TbetaRI/TbetaRII were investigated with dynamic force spectroscopy under different AFM loading rates. The dissociation rate constants of TGF-beta1 with its receptors as well as other parameters characterizing their dissociation pathways were obtained. The results suggested a more stable binding of TGF-beta1 with the receptor after TbetaRI is recruited and the important contribution of TbetaRI to the signaling complex formation during TGF-beta1 signaling.

Energy landscape of aptamer/protein complexes studied by single-molecule force spectroscopy.

Aptamers are single-stranded nucleic acid molecules selected in vitro to bind to a variety of target molecules. Aptamers bound to proteins are emerging as a new class of molecules that rival commonly used antibodies in both therapeutic and diagnostic applications. With the increasing application of aptamers as molecular probes for protein recognition, it is important to understand the molecular mechanism of aptamer-protein interaction. Recently, we developed a method of using atomic force microscopy (AFM) to study the single-molecule rupture force of aptamer/protein complexes. In this work, we investigate further the unbinding dynamics of aptamer/protein complexes and their dissociation-energy landscape by AFM. The dependence of single-molecule force on the AFM loading rate was plotted for three aptamer/protein complexes and their dissociation rate constants, and other parameters characterizing their dissociation pathways were obtained. Furthermore, the single-molecule force spectra of three aptamer/protein complexes were compared to those of the corresponding antibody/protein complexes in the same loading-rate range. The results revealed two activation barriers and one intermediate state in the unbinding process of aptamer/protein complexes, which is different from the energy landscape of antibody/protein complexes. The results provide new information for the study of aptamer-protein interaction at the molecular level.

Lateral diffusion of TGF-beta type I receptor studied by single-molecule imaging.

In this report, we investigated the lateral diffusion of transforming growth factor beta (TGF-beta) type I receptor (TbetaRI) in living cells by imaging and tracking individual green fluorescent protein tagged TbetaRI on the cell membrane. We found that when co-expressed with TGF-beta type II receptor (TbetaRII), the mobility of TbetaRI decreased significantly after TGF-beta1 stimulation. However, in the cells that had been depleted of cholesterol with Nystatin or methyl-beta-cyclodextrin, the diffusion rate of TbetaRI was not changed by TGF-beta1 treatment. Our observations suggest that membrane lipid-rafts provide an environment that facilitates the association of TbetaRI and TbetaRII for cell signaling.

[TLC-FT-SERS study on a pair of optic isomers in ephedra].

A new method for analyzing the ingredients of a pair of optic isomers in ephedra, nor-ephedrine and nor-pseudo-ephedrine, using hyphenated high-efficiency thin layer chromatography (TLC) and surface-enhanced Raman spectroscopy (SERS) techniques, is reported. The results show that the characteristic spectral bands of nor-ephedrine and nor-pseudo-ephedrine can be obtained from the TLC spot with 8 microg sample of about 2.0 mm in diameter. The difference between the SERS and solid spectra was found. Spectral bands at 1004 cm(-1) and 1605 cm(-1) were found greatly enhanced. Molecule was absorbed in surface silver sol by pi electrons in ring. Under similar experimental conditions the spectral information of Levo-nor-ephedrine ramifications TLC-SERS is rich with strong credibility, whereas dextral-nor-ephedrine ramifications show a relatively strong fluorescence backdrop with less spectral information and weak credibility. The effective combination of TLC and SERS can be used to analyse the chemical ingredients with high sensitivity.