No abstract

Gold nanoparticles (AuNPs) have widely been used for 70 years in cancer treatment, but only in the last 15 years has the focus been on specific AuNPs with homogeneous size and shape for various areas in science. They constitute a perfect platform for multifunctionalization and therefore enable the enhancement of target affinity. Here we report on the development of tumor specific AuNPs as diagnostic tools intended for the detection of prostate cancer via fluorescence imaging and positron emission tomography (PET). The AuNPs were further evaluated in vitro and in vivo and exhibited favorable diagnostic properties concerning tumor cell uptake, biodistribution, clearance, and tumor retention.

Optical systems applied for tissue analysis are primarily based on single spectroscopic techniques. This paper however presents a multispectral backscattering sensor designed for in vivo application by a specially formed probe tip which allows side by side monitoring of ultraviolet, visible, near-infrared and fluorescence spectra. The practical applicability of the measurement system was demonstrated in vitro (muscle and adipose tissue) and in vivo in an animal model (mouse). By comparing associated measuring changes in biochemical, physical-morphological and colorimetric values this procedure allows a differentiation between healthy, marginal and malignant tissue.

To date, few optical imaging systems are available in clinical practice to perform noninvasive measurements transcutaneously. Instead, functional imaging is performed using ionizing radiation or intense magnetic fields in most cases. The applicability of fluorescence imaging (e.g., for the detection of fluorescently labeled objects, such as tumors) is limited due to the restricted tissue penetration of light and the required long exposure time. Thus, the development of highly sensitive and easily manageable instruments is necessary to broaden the utility of optical imaging. To advance these developments, an improved fluorescence imaging system was designed in this study that operates on the principle of noncontact laser-induced fluorescence and enables the detection of fluorescence from deeper tissue layers as well as real-time imaging. The high performance of the developed optical laser scanner results from the combination of specific point illumination, an intensified charge-coupled device (ICCD) detector with a novel light trap, and a filtering strategy. The suitability of the laser scanner was demonstrated in two representative applications and an in vivo evaluation. In addition, a comparison with a planar imaging system was performed. The results show that the exposure time with the developed laser scanner can be reduced to a few milliseconds during measurements with a penetration depth of up to 32 mm. Due to these short exposure times, real-time fluorescence imaging can be easily achieved. The ability to measure fluorescence from deep tissue layers enables clinically relevant applications, such as the detection of fluorescently labeled malignant tumors.

No abstract