Commonly Used Nanomaterials in Molecular Imaging

1. Commonly Used Nanomaterials in Molecular Imaging CD Fluorescence Imaging Advantages: ●High sensitivity ●Multicolor imaging ●Activatable Disadvantages: ●Low spatial resolution ●Poor tissue penetration MRI SPECT Imaging Advantages: ●High spatial resolution ●No tissue penetrating limit Advantages: ●High sensitivity ●NO tissue penetrating limit Disadvantages: ●Relatively low sensitivity ●High Cost ●Long imaging time Disadvantages: ●Radiation risk ●Low spatial resolution Target PET Imaging CT Imaging Advantages: ●High spatial resolution ●No tissue penetrating limit Advantages: ●High sensitivity ●No issue penetrating limit ●Quantitative ●Whole-body scanning Disadvantages: ●Radiation risk ●Not quantitative Disadvantages: ●Radiation risk ●High cost Ultrasound Imaging Advantages: ●Real-time ●Low cost Disadvantages: ●Operator dependent analysis ●Low resolution Email: info@creative-diagnostics.com Tel: 1-631-624-4882

2. Nanomaterials (e.g. nanoparticles) display special physical and biological behavior and unique interactions with biomolecules. They possess large surface area and inherent functionalities, making structural modifications feasible to change their pharmacokinetics, prolong their vascular circulation life-time, improve their extravasation capacity, ensure an enhanced biodistribution in vivo and sustainably control the delivering efficacy for drug cargoes. In addition, nanoparticles conjugated with specific targeting ligands show a high targeted binding capability to diseased regions. Nanomaterials have been applied as efficient carriers for targeted drug delivery and therapeutic agents as well as for gene transportation. Molecular imaging is an attractive and fast-growing research field, in which several nanomaterials have been used as imaging agents (Table 1). As an emerging interdisciplinary research field, molecular imaging combines chemistry, biology, pharmacology, and medicine to monitor in vitro and in vivo biomedical or physiological processes at molecular and cellular levels, which provides valuable information for treatment strategies for various diseases. Table 1: Characteristics of several representative nanomaterials and their biomedical applications. Imaging Modality Applicable Type of Nanoparticle Possible Surface Modifications Synthetic Protocol Size Range Biological reduction, colloidal synthesis, vapor precipitation Lipids, polymeric shell, targeting ligands or biomolecules Gold nanoparticle Several to hundreds of nm CT, optical imaging Silica nanoparticle Chemical polymerization, microemulsion, sol-gel Tens to hundreds of nm Charge, polymer, targeting ligands or biomolecules MRI, optical imaging Arc discharge, laser ablation, vapor precipitation Carbon nanotube Polymeric shell, targeting ligands or biomolecules MRI, optical, radionuclide imaging Tens of nm Colloidal synthesis, self- assembly, viral assembly Lipids, polymer, targeting ligands or biomolecules Quantum dot Several to tens of nm Optical imaging Coprecipitation, decomposition, microemulsion, sol-gel, thermal Charge, dextran, lipids, polymer, targeting ligands or biomolecules Iron oxide Several to tens of nm MRI Several nm varies from different “generation” Organic chemistry techniques Charge, polymer, targeting ligands or biomolecules Dendrimer MRI, optical imaging Charge, polymer, targeting ligands or biomolecules, viral protein coating, Tens to hundreds of nm MRI, optical, radionuclide imaging Liposome Emulsion, polymerization Emulsion, layer-by-layer fabrication, polymerization Tens to thousands of nm Polymeric shell, targeting ligands or biomolecules Microbubble Ultrasound imaging Charge, polymer, targeting ligands or biomolecules MRI, optical, radionuclide imaging Micelle Microemulsion Tens of nm Tens to hundreds of nm Charge, polymer, targeting ligands or biomolecules Adenovirus Replication in host nucleus MRI, optical imaging Email: info@creative-diagnostics.com Tel: 1-631-624-4882

3. Design and Functionalization of Nanoparticles in Molecular Imaging ◆ Five aspects need to be considered when developing an imaging agent with nanoparticles: 1) The toxicity of nanoparticles for living subjects and humans; 2) Any possible metabolites after vascular circulation or cell uptake; 3) The biocompatibility and biodegradability to avoid harmful accumulations in organs, tissues, and 4) The availability for chemical modifications of nanoparticles; 5) The in vitro and in vivo comprehensive assessments of synthesized nanoparticles before practical ◆ The common methodologies for design and functionalization strategies of nanoparticles are summarized below: 1) Select and fabricate nanoparticles core Based on imaging purposes and a specific imaging modality, the core of the nanoparticle is selected and the synthesis method of fabrication of the structure of imaging probes is determined. 2) Synthesize shell structure Compared with the core of nanoparticles, the shell structure usually possesses more complicated functions including preventing the core from the external microenvironment and improving the core stability and physical property. 3) Modify surface To maintain the nanoparticles' stability, surface coatings with stabilizers or emulsions may be necessary if the outer interface of the shell is too sensitive when exposed to bio-medium. blood; applications for living subjects or humans. Nanomaterials Used in Different Molecular Imaging • Fluorescence imaging Fluorescence imaging is one of the major techniques in optical imaging to analyze the propagation of nonionizing radiation, light photons through a medium such as tissue. It is the visualization of molecular processes or structures via fluorescent dyes or proteins. Fluorescence imaging can be applied in a wide range of experiments such as the location and dynamics of gene expression, protein expression, and molecular interactions in cells and tissues. Email: info@creative-diagnostics.com Tel: 1-631-624-4882

4. Table 2. Selected examples of nanomaterials used in fluorescence imaging. NP Type Imaging Agent Size (nm) Applications Cy5.5-substrate/AuNP Cy5.5 20 Detecting protease activity Testing caspase-3 to identify apoptosis activity in cells Cy5.5-DEVD-DOPAK/AuNP Cy5.5 37.8 Monitoring NP accumulation and dissociation kinetics in tumor QD710-Cy7-PEGylated lipids Cy7 20 QD710-Dendron/RGD (InP/ZnS core/shell QDs) Perylenediimide-containing polysiloxane core and silica shell Quantum dots 12 Targeted imaging tumor cells Perylenediimide 18, 70 Detecting nanotoxicity in alive cells AB3-UCNP(NaYF4:Yb/Tm/Er)- RB/KE108 Monitoring cellular uptake of nanoparticles and combined with therapy UCNP 14 AuNP: gold nanoparticle; QD: quantum dot; UCNP: upconverting nanoparticle. • MRI MRI, magnetic resonance imaging, is one of the most widely used and powerful tools for noninvasive clinical diagnosis. It possesses a high degree of soft-tissue contrast, spatial resolution, and depth of penetration. There are several advantages of using nanoparticles as imaging probes compared with conventional imaging agents: 1) the concentration of the imaging agent is controllable in each nanoparticle during the synthesis process; 2) the tunability of the nanoparticles' surface is beneficial to target a specific location in the body and prolong the circulation time of the agent in the blood; 3) nanoparticles can be used as multifunctional molecular imaging agents due to their two or more properties. Table 3. Selected examples of nanomaterials used in MRI. NP Type Size (nm) Applications Imaging Alpha(nu)beta(3)-Gd (paramagnetic particle) 273 Imaging angiogenesis T1 Liposomal gadolinium 125 Imaging placenta as blood-pool contrast T1 RBC encapsulated iron particles 60 Blood-pool contrast with longer lifetime T1, T2 PEGMnCaP NPs 60 PH-activatable contrast in cancer T1, T2 USPIO-PEI 100 Determining nanoparticle vehicle unpackaging for gene T2 P-selectin-MNP(iron oxide)-PBP 50 Imaging post-stroke neuroinflammation T2 NP: nanoparticle; USPIO: ultra-small superparamagnetic iron oxide; MNP: magnetic nanoparticle. Email: info@creative-diagnostics.com Tel: 1-631-624-4882

5. • CT imaging Computed tomography (CT) is an X-ray based, a whole-body imaging technique and is widely used in medicine. Although iodinated small molecules or barium suspensions are clinically approved contrast agents for CT, developing nanoparticle-based CT contrast agents have attracted more attention due to the growing population of renally impaired patients and those who are hypersensitive to iodinated contrast. Nanoparticle-based CT contrast agents possess several advantages over small molecule ones, including long blood-pool residence times, and the potential for cell tracking and targeted imaging applications. Table 4. Selected examples of nanomaterials used in CT imaging. NP Type Size (nm) Applications PSMA-specific aptamer conjugated AuNP 29.4 Imaging prostate cancer cells Liposomal iodine 400 Imaging macrophage-rich atherosclerotic plaques Tantalum oxide <6 Producing greater imaging capability than iodine AuNP 20 Incorporating RBC to image blood flow AuNP 27–176 AuNP with CT contrast capability AuNP: gold nanoparticle. • Ultrasound imaging Ultrasound (US) imaging is a diagnostic medical procedure that uses high-frequency sound waves to view inside the body. As real-time captured imaging, ultrasound images can not only show the movement of the body's internal organs but also present the blood flowing through the blood vessels. This technique does not require the use of ionizing radiation, nor the injection of nephrotoxic contrast agents. Since there is a great progress in the discovery of various disease-specific biomarkers and in the development of nanoparticle fabrication, nanoparticle-based ultrasound contrast agents have made a big development. Those contrast agents could extravasate through the leaky vasculature of a tumor into the interstitial space with less echogenic than microbubbles. Table 5. Selected examples of nanomaterials used in ultrasound imaging. NP Type Size (nm) Applications Classification Silica coated NP into perfluorobutane microbubble Ultrasound imaging agents with potential therapeutic applications Near 3000 Gas Exosome-like silica NP 30–150 Stem cell imaging agent Solid Gas-NP 290 PH related contrast agents in tumor Gas Porphyrin nanodroplet FA-PEG-CS and perfluorooctyl bromide nanocore 185 Tumor imaging contrast agent Gas 229.5 Molecular tumor imaging agents Liquid AuNP: gold nanoparticle. Email: info@creative-diagnostics.com Tel: 1-631-624-4882

6. • PET/SPECT imaging As a powerful and widely used nuclear medicine technology, PET (positron emission tomography) possesses high tissue penetration and high sensitivity and is ideal for real-time quantitative imaging analysis. Similar to PET, SPECT (single-photon emission computed tomography) is also widely used nuclear medicine technology which can detect abnormal biochemical function before changes in anatomy. Both of them are suffered from high costs and radioactive exposure. Nanoparticles in PET/SPECT are generally used for tumor detection. Tumor imaging can occur through specific binding to receptors or via the EPR effect as well as being acquired through active and passive accumulation in target lesions. Table 6. Selected examples of nanomaterials used in PET/SPECT imaging. NP Type Size (nm) Applications Imaging Modality 18 F-labeled DBCO-PEGylated MSN 100–150 Imaging tumor PET 64 Cu labeled CANF-comb nanoparticle Imaging natriuretic peptide clearance receptor in prostate cancer Imaging macrophages in inflammatory atherosclerosis 16–22 PET 64 Cu-TNP 20 PET 125 I silver nanoparticle 12 Monitoring distribution of nanoparticles SPECT Detecting cancer cells and imaging tumor sites 125 I labeled cRGD-PEG-AuNP 31 SPECT MSN: mesoporous silica nanoparticle; TNP: tri-reporter nanoparticle; AuNP: gold nanoparticle. Each imaging modality has its own unique strengths. Multimodality imaging, combining two or more imaging modalities, can provide more comprehensive structural, functional and molecular information, which offers the prospect of improved diagnostics and therapeutic monitoring abilities. Nanoparticles have been used for the development of dual-modal or multimodal probes at an incredibly fast rate. For example, as dual-modal imaging probes, nanoparticles administrate a single contrast agent for different types of imaging modalities and possess signal consistency at the target region. Creative Diagnostics has presented a summary of commonly used nanomaterials in molecular imaging. If you desire any raw materials mentioned above, please visit our website to see more. Email: info@creative-diagnostics.com Tel: 1-631-624-4882

7. References: 1. Polyak, A., & Ross, T. L. (2018). Nanoparticles for SPECT and PET imaging: towards personalized medicine and theranostics. Current medicinal chemistry, 25(34), 4328-4353. 2. Pratiwi, F. W., Kuo, C. W., Chen, B. C., & Chen, P. (2019). Recent advances in the use of fluorescent nanoparticles for bioimaging. Nanomedicine, 14(13), 1759-1769. 3. Cormode, D. P., Naha, P. C., & Fayad, Z. A. (2014). Nanoparticle contrast agents for computed tomography: a focus on micelles. Contrast media & molecular imaging, 9(1), 37-52. 4. Mallidi, S., Wang, B., Mehrmohammadi, M., Qu, M., Chen, Y. S., Joshi, P., ... & Sokolov, K. (2009, September). Ultrasound-based imaging of nanoparticles: From molecular and cellular imaging to therapy guidance. In 2009 IEEE International Ultrasonics Symposium (pp. 27-36). IEEE. 5. Lee, D. E., Koo, H., Sun, I. C., Ryu, J. H., Kim, K., & Kwon, I. C. (2012). Multifunctional nanoparticles for multimodal imaging and theragnosis. Chemical Society Reviews, 41(7), 2656-2672. 6. Estelrich, J., Sánchez-Martín, M. J., & Busquets, M. A. (2015). Nanoparticles in magnetic resonance imaging: from simple to dual contrast agents. International journal of nanomedicine, 10, 1727. 7. Burke, B. P., Cawthorne, C., & Archibald, S. J. (2017). Multimodal nanoparticle imaging agents: design and applications. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 375(2107), 20170261. 8. Liu, Z., Kiessling, F., & Gätjens, J. (2010). Advanced nanomaterials in multimodal imaging: design, functionalization, and biomedical applications. Journal of Nanomaterials, 2010, 51. 9. Han, X., Xu, K., Taratula, O., & Farsad, K. (2019). Applications of nanoparticles in biomedical imaging. Nanoscale, 11(3), 799-819. For more information, view our website: www.cd-bioparticles.com Tel: 1-631-624-4882 Email: info@creative-diagnostics.com Fax: 1-631-938-8221 Address: 45-1 Ramsey Road, Shirley, NY 11967, USA 5