This paper is based on the shanghai city award for natural sciences, award no. 1 in 2022, entitled “modern synthesis, performance regulation and basic research in biological applications of near-infrared probes in rare land”, which was completed by professor zhang fan, faculty of chemistry, university of joahan。
A long journey of discovery
The discovery of rare earth began in northern europe, where in 1787, in a village near stockholm, sweden, called yteerby, amateur mineralist c. A. Arrhenius found a black ore that he had never seen and named it yteerite by name. It opens the door to rare earth elements. Immediately thereafter, in 1794, the finnish chemist j. Gadolin discovered a new element of this mineral, the “earth” named yteelium. It is limited to the separation technology at the time, and the “plain soil” is actually a mixed rare earth oxide. Due to their similarity, rare earth elements are treated as an element. With the development of industrial purification and smelting technologies, scientists have successively discovered rare earth elements, such as platinum, platinum, etc., from this “earth”. Also in 1803, nine years after the discovery of the “earth”, the swedish chemist j. J. Berzelius and his teacher w. Hisingerr found the “earth”. It was followed by the separation of rare earth elements, such as thorium, thorium and thorium. Thus, it was not until 1947 that j. A. Marinsky, the american, and his colleagues, separated the last rare earth element from uranium waste in the atomic reactor, for a total of 153 years, to complete the full development history of 17 rare earth elements. With the discovery of rare earth elements, the technology of purification for the separation of rare earth has been improving, and it has only begun to emerge in various fields。
Shine
The magic of rare earth elements is first and foremost manifested in their special photogenic properties, in particular their photogenic properties, which were observed by polish chemists boguslaw köczyński and french chemist georges urbain as early as the late nineteenth to early twentieth centuries. They found that certain rare earth elements sent light of a specific colour when exposed to ultraviolet light or high-energy electronic bombardment. In the middle of the twentieth century, applications of rare-earth light materials in lighting and display technology became hot spots for research and were widely used in areas such as television, computer monitors and energy-saving lamps。
The luminous properties of rare earth elements derive mainly from electronic leaps in its unfilled 4f electro-orbit, resulting from the presence of rare earth ions in different forms of electronic leaps and extremely rich energy-grade leaps. Viable passages are usually found in visible and infrared areas. Thus, rare earth ions can absorb or launch a variety of wavelengths from ultraviolet to infrared areas to form a variety of light materials. In addition, rare earth elements usually have a light life of microseconds to milliseconds, which allows them to be distinguished from short-lived background fluorescent and applied to applications requiring sustained light, such as light storage materials and persistent fluorescent marks. The specific optical properties of rare earth elements provide a rich resource for the development of new optical materials and devices. In the twenty-first century, rare earth luminescence material was widely used in new display techniques (e. G. Led and old) and rare earthly mixed nanoparticles were widely used in bioimaging and sensory techniques because of their unique optical properties。
The probe
At the end of the twentieth century, scientists began to explore rare earth-mixed nanomaterials, and most of the rare earth ion-mixed nanoprobes had a narrower absorption and emit spectrum, initially focusing on their phototransformation from longer infrared to shorter wavelengths. However, the short wavelength visible light (400-700 nm) is easily absorbed and dispersed through biological tissues, thus satisfying only in vitro diagnostics and biological imaging at cell level. Near infrared light (nir, 700 to 1700 nm) can penetrate biological tissue in greater depth than visible or ultraviolet light, making it well suited to deep internal imaging. As a result, the subterranean subterranean luminous near-infrared sector window, which is a relatively “transparent” optical window for biological tissue, has deeper tissue penetration and higher imaging noise due to weaker absorption and dispersion and lower self-luminescent fluorescence, especially in the near-infrared sector 2 of 1000 nm-1700 nm. Of these, pr3+, nd3+, ho3+, er3+, tm3+, which is within a spectrum of 1,000 nm-1700 nm because of its launch wavelength, is the light centre commonly used in the transfer of light from nanoparticles. Advantages such as low toxicity, high chemical stability, narrow-band discharge and long fluorescent lifetime of rare earth-mixed nanoparticles have been increasingly applied in such areas as bioimage, optical sensing and disease treatment。
However, due to the relatively small absorption cross-section of rare earth ion and the fact that the leap between the f-f orbits is prohibited, the conversion of light into nanoparticles is less efficient in the general field, and the development of high sensitivity fluorescent systems has been an important element in the study of rare earth immersion of nanoparticles. It's also the key to the clinical application of rare earth to nanoprospecting needles. As nanotechnologies develop, the synthesis process and sex of rare earth near-infrared probes can be further enhanced, with common rare earth light-modulation strategies, including dye sensitization, element mixing, hull structure design, surface alteration, etc。
The zhang fan team at the university of joadan has been working on the development of near-infrared fluorescent molecule probes and has long been engaged in the design synthesis and application of rare-earth fluorescent nanomaterials. Zhangfan graduated in 2008 from the zhao dong councillors ' team at the faculty of chemistry at the university of jordan. Initially, zhangfan followed mr. Zhao in research into the inorganic and porous material field, and in the course of the study, zhang zhang zhang zhang slowly found in literature reading areas of more luminous material of his own interest. With the support of mr. Zhao, zhang fan has embarked on a course of research with light materials during his doctorate, and has produced excellent research results. Zhang van went to the united states of america to join professor galen stucky, united states of america, at the university of california in santa barbara, after his graduation in 2008, to conduct post-doctoral research and continue research on rare earth. Since the return of the post-doctoral study from the united states in 2010, professor zhang has focused on the field of near-infrared 2 imaging, including rare earthen nanometer probes, organic small molecule probes, chemical light probes, etc., and professor zhang has outlined his research as an exploration of the “infrared optical imaging window of the living deep organization”。
In an ongoing in-depth study of rare-earth luminous nanomaterials, the zhang team found that the exploration of in situ biological mechanisms for living animals is of particular importance for the diagnosis and treatment of diseases, but that the optical penetration and imaging resolution of near-infrared fluorescent imaging has not yet been fully developed as a result of the dispersion and absorption of tissues (such as skin, fat, bones, etc.) in organisms during light transmission。
In order to increase the light intensity of the rare earth, the zhang team, in its exploration, tried to increase the absorption cross of the rare earth ion by means of the hull structure, and proposed a single-atom continuous growth method to construct the hull structure of the rare earth nanoparticles to increase the light efficiency and stability of near-infrared probes through layer construction. They have also tried to explain the mechanisms for regulating the energy transport of the luminous nanoshell layer of rare earth ion through precision regulation of the structure of the hull at the level of yanami, and have therefore constructed a series of near-infrared second-window fluorescent probes with different wavelengths, which provide important tools for bioimaging of living organisms。
In addition, in order to further overcome the impact of tissues on light dispersion and absorption in organisms, zhang's team attempted to use the long fluorescent lifetime characteristics of rare earth ions to develop time-dimensional bioimaging methods, using the fluorescent lifetime detection techniques of the near-infrared second window of the rare earth ion, to achieve multiple imaging of the living body in which the tissue penetrates at depths of 3 cm to 5 cm, to significantly increase the sensitivity of detection and organizational penetration in the analysis of living body imaging, and to address the challenge of the multi-quantitative detection of near-infrared fluorescent probes at the living body depth。
For more than a decade, the zhang fan team has been working on the preparation of near-infrared light probes, giving a multi-materialization character to rare-earth nanoparticles by increasing their fluorescent launch and fluorescent fluorescent life and combining the surface functionality of nanomaterials. At the same time, important breakthroughs have been made in the construction of near-infrared bioimaging instruments and in live fluorescent life imaging technologies, which have contributed significantly to biomedical analytical research。
As professor zhang zhang has stated, rare earth near-infrared light probes are like opening a window to observe the insides of organisms, and are automatically located in an organ or tissue through rare earth nanomaterials, allowing for precision detection of specific organisms, and obtaining information on the dynamics of organisms such as intestinal worms, tumour cell evaporation and blood vessels distribution. Its immediate, high-resolution and ingenuity advantages provide better prospects for application in the field of precision surgical navigation techniques and are expected to be a new and innovative method of diagnosis of oncological pathology. The combination of rare earthen nanomaterials with other treatments (e. G. Photothermal therapy, photodynamic therapy, target delivery to drugs) may provide entirely new treatment strategies for major diseases such as cancer。
