Peptide Modification for Diagnostic Tools

Peptides are composed of amino acids and are highly specific and biocompatible. In modern medical research and clinical applications, peptide modification technology is widely used in the development of diagnostic tools. These modifications, including fluorescent labeling, peptide-modified metal clusters, etc., greatly improve the accuracy and efficiency of diagnosis. This article will explore the application of peptide modification in diagnostic tools and provide examples to help understand.

Peptide-modified metal clusters in cancer diagnosis

Metal clusters offer a cohesive data processing standard for the multidimensional diagnosis and detection of body fluids, cells, and tissues, thereby enhancing diagnostic accuracy and consistency. For instance, research has demonstrated that peptide-modified metal clusters present notable advantages in cancer diagnosis. By integrating peptides with metal clusters, cancer cells can be efficiently identified and imaged, leading to more precise early cancer detection. The superior biocompatibility of metal clusters within the body and their rapid renal clearance makes them exceptionally suitable for practical applications, further advancing their development in the realms of bioanalysis and diagnostics. Consequently, metal clusters are poised to become a cornerstone technology in medical diagnostics, contributing to more reliable and timely disease detection and monitoring.

Fig.1 Application of peptide modified metal clusters in cancer diagnosis. (Su Dongdong, et al., 2020)

Table 1. Peptide modification service at Creative Peptides

Peptide-modified nanoprobes in molecular probes

Peptide-modified nanoprobes take advantage of the unique properties of nanomaterials, such as high surface area and versatility, making them promising for a wide range of applications in disease diagnosis. Peptide modifications can enhance the targeting and biocompatibility of nanoprobes, thereby improving their stability and detection sensitivity in vivo. For example, peptide-modified nanoprobes can be used for the detection of tumor markers. By combining peptides that specifically recognize tumor markers with nanomaterials, the probe can efficiently capture and detect target markers, enabling early tumor diagnosis. In addition, there is an increasing demand for intraoperative navigation imaging, which is expected to provide doctors with clear vision through high-contrast and stable fluorescence imaging. Based on Bioactivated In Vivo Assembly Nanotechnology (BIVA), Li's team constructed near-infrared nanoprobes for intraoperative navigation imaging of micro-orthotopic pancreatic tumors through modular peptide probe molecular design, realizing accurate intraoperative navigation imaging of microscopic lesions and greatly improving the success rate of clinical tumor surgery.

Fig.2 Chemical structure and application of probe BIVA. (Li Li-Li, et al., 2022)

Fluorescent peptide modifications in bioimaging

Fluorescent peptides are the chemical method of attaching a fluorophore to a peptide molecule so that it fluoresces under light excitation at a specific wavelength. Fluorescent peptides can be used for imaging, localization, and research models, and they have important applications in biomedical imaging. Fluorescently labeled peptides can be used to identify specific biological targets, such as in angiography, which can label vascular structures to help doctors better observe and diagnose vascular diseases. A specific application example is the use of fluorescent peptides in enzyme activity assays. Enzymes are important catalysts in living organisms, and the activity of enzymes can be monitored in real-time through the modification of fluorescent peptides. For example, researchers can use fluorescently labeled peptides to detect the activity of proteolytic enzymes, thereby screening for enzyme inhibitors with potential therapeutic effects. This is of great significance for the development of novel disease models and understanding of disease mechanisms.

Functional peptides for CT examinations

CT is a powerful diagnostic tool based on differences in X-ray absorption, providing high-resolution 3D tomography images. CT imaging often uses high X-ray attenuating contrast agents such as iodine, barium, bismuth, etc., to enhance contrast. The dosage of metal contrast agents is high, the adverse reaction is large, and the use is inconvenient. Functional peptides, on the other hand, are easy to prepare and store, stable in nature, and have rapid metabolic clearance in vivo, making them ideal compounds for CT molecular imaging probes. A research team synthesized a 99Tcm-labeled CTP peptide (APWHL SSQYS RT) to target heart tissue, and radiochemical experiments have shown that a sufficient amount of radiation can be delivered to the heart using microgram level (7-15 μg) of CTP, which is similar to the current clinical dose of 99Tcm-methoxy isobutyl isobutonitrile (99Tcm-Sestamibi), and the peak myocardial uptake reaches at the fastest 5 min after administration, which is mainly excreted by the kidneys to shorten the residence time in the body. The effects of contrast radiation are minimized. In addition, experiments with human IPSCs have shown that CTP is not limited to species restrictions, not only for its transduction ability to the mouse heart, but also for it has potential for human application as a novel cardiac targeting vector for diagnostic imaging and targeted therapy.

Summary

As a new technology in the field of diagnostic tools, peptide modification has shown a wide range of potential applications. The adjustment of peptide structure and the optimization of chemical properties are the key ways to improve the sensitivity, specificity, and stability of peptides in diagnosis. These advantages not only significantly improve the accuracy and consistency of diagnostic tools, but also help achieve more accurate results in important areas such as early cancer diagnosis. The technological progress and in-depth research of peptide modification predict its wide application in medical diagnosis and bioanalysis. For example, by precisely controlling the structure of peptides, highly selective probes for specific biomarkers can be designed, enabling more precise quantitative and qualitative analyses in the diagnosis of body fluids, cells, and tissues. The development of these technologies not only expands the application range of current diagnostic tools, but also provides strong support for future innovations and is expected to play an important role in molecular diagnostics, personalized medicine, and drug therapy monitoring.

References

1. Thakur, Reena, et al., Peptides as diagnostic, therapeutic, and theranostic tools: Progress and future challenges. Critical ReviewsTM in Therapeutic Drug Carrier Systems 40.1 (2023).
2. Su, Dongdong, et al., Peptide and protein modified metal clusters for cancer diagnostics. Chemical Science 11.22 (2020): 5614-5629.
3. Yin, Hong, et al., iRGD as a tumor‑penetrating peptide for cancer therapy. Molecular medicine reports 15.5 (2017): 2925-2930.
4. Li, Li-Li, et al., A bioactivated in vivo assembly (BIVA) nanotechnology fabricated NIR probe for small pancreatic tumor intraoperative navigation imaging. Nat Commun 13, 418 (2022).
5. Pan, Deng, et al., A general strategy for developing cell-permeable photo-modulatable organic fluorescent probes for live-cell super-resolution imaging. Nature communications 5.1 (2014): 5573.