Advancing X-ray Luminescence for Imaging, Biosensing, and Theragnostics

Abstract

Conspectus X-ray luminescence is an optical phenomenon in which chemical compounds known as scintillators can emit short-wavelength light upon the excitation of X-ray photons. Since X-rays exhibit well-recognized advantages of deep penetration toward tissues and a minimal autofluorescence background in biological samples, X-ray luminescence has been increasingly becoming a promising optical tool for tackling the challenges in the fields of imaging, biosensing, and theragnostics. In recent years, the emergence of nanocrystal scintillators have further expanded the application scenarios of X-ray luminescence, such as high-resolution X-ray imaging, autofluorescence-free detection of biomarkers, and noninvasive phototherapy in deep tissues. Meanwhile, X-ray luminescence holds great promise in breaking the depth dependency of deep-seated lesion treatment and achieving synergistic radiotherapy with phototherapy. In this Account, we provide an overview of recent advances in developing advanced X-ray luminescence for applications in imaging, biosensing, theragnostics, and optogenetics neuromodulation. We first introduce solution-processed lead halide all-inorganic perovskite nanocrystal scintillators that are able to convert X-ray photons to multicolor X-ray luminescence. We have developed a perovskite nanoscintillator-based X-ray detector for high-resolution X-ray imaging of the internal structure of electronic circuits and biological samples. We further advanced the development of flexible X-ray luminescence imaging using solution-processable lanthanide-doped nanoscintillators featuring long-lived X-ray luminescence to image three-dimensional irregularly shaped objects. We also outline the general principles of high-contrast in vivo X-ray luminescence imaging which combines nanoscintillators with functional biomolecules such as aptamers, peptides, and antibodies. High-quality X-ray luminescence nanoprobes were engineered to achieve the high-sensitivity detection of various biomarkers, which enabled the avoidance of interference from the biological matrix autofluorescence and photon scattering. By marrying X-ray luminescence probes with stimuli-responsive materials, multifunctional theragnostic nanosystems were constructed for on-demand synergistic gas radiotherapy with excellent therapeutic effects. By taking advantage of the capability of X-rays to penetrate the skull, we also demonstrated the development of controllable, wireless optogenetic neuromodulation using X-ray luminescence probes while obviating damage from traditional optical fibers. Furthermore, we discussed in detail some challenges and future development of X-ray luminescence in terms of scintillator synthesis and surface modification, mechanism studies, and their other potential applications to provide useful guidance for further advancing the development of X-ray luminescence.

Editorial: Specialty grand challenge: Structure, spectroscopy, and imaging

“…Nevertheless, many spectroscopic approaches allowed remarkable enlightening advancements in the field. More recently, advanced X-ray luminescence methodologies for applications in imaging, biosensing, and theranostics, by using inorganic perovskite nanocrystal scintillators, provided high-resolution X-ray imaging of the internal structure of biological samples (Hong et al, 2023).…”

Centimeter‐Sized Single Crystals of Dion‐Jacobson Phase Lead‐Free Double Perovskite for Efficient X‐ray Detection

“…X-ray detection has been widely used in the fields of medical diagnostics, nondestructive determination, nuclear reaction monitoring, etc. [1][2][3][4][5][6][7][8] At present, traditional semiconductors have dominated the market for X-ray detecting materials, such as crystalline Si and amorphous selenium (α-Se). [9][10] However, the issues of complex fabrication techniques and high-energy 2D Dion-Jacobson (DJ) phase hybrid perovskites have shown great promise in the photoelectronic field owing to their outstanding optoelectronic performance and superior structural rigidity.…”

“…X‐ray detection has been widely used in the fields of medical diagnostics, nondestructive determination, nuclear reaction monitoring, etc. [ 1–8 ] At present, traditional semiconductors have dominated the market for X‐ray detecting materials, such as crystalline Si and amorphous selenium (α‐Se). [ 9–10 ] However, the issues of complex fabrication techniques and high‐energy consumption are the concerns that hinder their large‐scale application.…”

A sandwiched luminescent heterostructure based on lanthanide‐doped Gd2O2S@NaYF4 core/shell nanocrystals

“…This deficiency has greatly limited the application of lanthanide oxysulfide NCs in many advanced technologies such as multimodal bioimaging, nanoscintillators, and photocatalysis. [ 28–32 ]…”