Customized Labeled Nano-tracer as Imaging Tools

With the development of molecular imaging and material science, single domain antibody (sdAb)-targeted imaging technology has attracted extensive attention in the academic area. Many sdAb-based tracers using either nuclear, fluorescent labels or nanobubble/microbubble have been heavily investigated pre-clinically and are currently making their way into the clinic. Armed with rich experience in the production of sdAb and non-invasive molecular imaging research, Creative Biolabs provides customized nano-tracer development services with various labels. We provide tailored imaging tools to support your research in different fields ranging from cancer, inflammation with sdAbs, tumor extracellular matrix, to checkpoint molecules and immune responses.

Radiolabeled sdAbs for Molecular Imaging

Nuclear molecular imaging requires the targeting moiety, in our case is a sdAb, to be labeled with a diagnostic radioisotope. The latter can either be a gamma-emitting isotope for single photon emission computed tomography (SPECT) or a positron-emitting isotope for positron emission tomography (PET). ^99mTc-tricarbonyl reacts site-specifically with a genetically inserted C-terminal hexahistidine tag, which can also be used for purification purposes via immobilized metal affinity chromatography. Radiolabeling of proteins with other radiometals (such as ⁶⁴Cu, ⁶⁸Ga, and ⁸⁹Zr for PET or ⁶⁷Ga and ¹¹¹In for SPECT) or radiohalogens (such as ¹⁸F and ¹²⁴I for PET and ^123/131I for SPECT) usually necessitates the use of a chelator for complexation or a prosthetic group for electrophilic substitution, respectively.

NIR dyes-conjugated SdAbs for Molecular Imaging

Different from radiolabeled imaging, fluorescence imaging requires the presence of a fluorescent label for sensitive detection. Though a wide range of fluorescent dyes are available for biotechnological purposes, for in vivo imaging applications, the choice of fluorophore is limited to those emitting in the near-infrared (NIR) region, and more specifically, those with a maximal excitation and emission wavelength between 650 and 900 nm. Commonly, hydrophilic (sulfonated) variants of cyanine dyes with a penta- or heptamethine chain are used, such as Cy5, Alexa Fluor 680, IRDye680RD, IRDye700DX or IRDye800CW.

Fig.1 Bioluminescence Imaging of Inflammation by decorated nanobubble. (Liu, 2019)

Ultrasound-targeted Nanobubble for Molecular Imaging

Active targeting rapidly and selectively enhances tumor accumulation and tumor retention. These processes could be also visualized and quantified in real-time with ultrasound. Ultrasound imaging makes use of sound waves which are reflected differently by different tissues and organs. Microbubbles are generally used as contrasting agents and sdAb mediated guidance can further aid in improving contrast at the desired location. Due to the micrometer size, the proteins targeted should be located in the vasculature of the tumor such as VCAM-1 and PSMA. The application of sdAb-targeted microbubbles is beneficial since it can provide safe, fast and inexpensive scanning together with relatively high-quality images.

Services

• sdAb generation and optional modification
• Label design and conjugation
• Molecular imaging services in the disease model
• Comprehensive data analysis

If you are interested in our customized labeled nano-tracer development services, please directly contact us for more information.

Reference

1. Liu, R.; et al. Bioluminescence imaging of inflammation in vivo based on bioluminescence and fluorescence resonance energy transfer using nanobubble ultrasound contrast agent. ACS nano. 2019, 13(5): 5124-5132.

For Research Use Only.