Multiparametric Evaluation of the Acoustic Behavior of Halloysite Nanotubes for Medical Echographic Image Enhancement

Abstract

Halloysite nanotubes (HNTs) are nanomaterials composed of double layered aluminosilicate minerals characterized by a wide range of medical applications. Nonetheless, systematic investigations of their imaging potential are still poorly documented. This paper shows a parametric assessment of the effectiveness of HNTs as scatterers for safe ultrasound (US)-based molecular imaging. Quantitative evaluation of average signal enhancement produced by HNTs with varying set up configuration was performed. The influence of different levels of power (20%, 50%, and 80%) of the signal emitted by clinical equipment was determined, to assess the efficacy of different HNT concentrations (1.5, 3, and 5 mg/mL) at conventional ultrasonic frequencies (5.7-7 MHz), even in case of specific limitation regarding US mechanical interaction with target tissues. Different samples of HNT containing agarose gel were imaged through a commercially available echographic system and acquired data were processed through a dedicated prototypal platform to extract the average ultrasonic signal amplitude. The rate of signal enhancement achieved by different concentration values was quantified and the contribution of frequency increment was separately evaluated. Despite influencing the level of mechanical excitation on HNTs and tissues, our results demonstrated how increasing the power of the emitted signal negatively affected the measured backscatter. Conversely, noticeable improvements in signal backscatter could be achieved incrementing HNT concentration and the echographic frequency employed; specifically the signal enhancement over the used concentration range could be improved by averagely 20%, corresponding to 4.86 ± 0.80 (a.u.), when employing the higher value of echographic frequency.

Multicavity halloysite–amphiphilic cyclodextrin hybrids for co-delivery of natural drugs into thyroid cancer cells

“…For instance, biomedical applications of HNTs include their use as gene delivery systems, cancer cell isolation, stem cell isolation, ultrasound contrast agents, bone implants, teeth fillers, cosmetics and controlled drug delivery. [3][4][5][6][7][8] Cyclodextrins (CDs) are very promising materials in several fields. It is known that these macrocyclic compounds form inclusion complexes with small-and medium-sized organic molecules and the complexation reactions that are involved are highly important in drug delivery systems.…”

An Innovative Ultrasound Signal Processing Technique to Selectively Detect Nanosized Contrast Agents in Echographic Images

“…This specific trend has become more evident after the introduction of the novel nanosized contrast agents, potentially capable of adding molecular sensitivity, which was previously limited to nuclear medicine techniques, also to nonionizing imaging approaches [2]- [9]. The cheapest and most common nonionizing imaging technology is represented by US-based methods, which could also take the mentioned advantages from the employment of suitable nanosized contrast agents.…”

“…An Innovative Ultrasound Signal Processing Technique to Selectively Detect Nanosized Contrast Agents in Echographic Images agent particles able to target specific pathological cells within the body after intravenous injection [2]- [9], with enormous improvements in disease detection accuracy toward the so-called molecular imaging [10]. In this context, ultrasound (US)-based imaging techniques, which, because of their well-known advantages (the absence of ionizing radiation, low costs, portability, and wide availability), are being continuously improved and optimized [11]- [15], might gain particular benefits, since the newer NP agents can directly overcome the specific limitations of the current clinically available US contrast agents, consisting of encapsulated gas-filled microbubbles.…”

Automatic image detection of Halloysite clay Nanotubes as a future ultrasound theranostic agent for tumoral cell targeting and treatment

“…Our results denote that sensitivity values increased from the lowest to the highest employed HNT concentration, whereas specificity decreased of a considerably smaller amount (Fig.3). [19], [28], allowing harmonic ultrasound imaging [29] and multimodal imaging combining ultrasound and magnetic resonance imaging [29]- [31]. whereas cellular and animal studies of HNT tolerability are available, future work will be devoted to further characterize HNT as UCA and theranostic vector for clinical application.…”