Abstract: The present application provides a method for preparing a probiotic-loaded microcapsule including: (1) dissolving sodium alginate in a solvent to obtain a sodium alginate solution; (2) evenly mixing a probiotic with the sodium alginate solution obtained in step (1) to obtain a probiotic suspension; and (3) spraying the probiotic suspension obtained in step (2) into a salt solution, stirring and curing, to obtain the probiotic-loaded microcapsule. The microcapsule is prepared by a spraying method in conjunction with an ion curing method by using sodium alginate as the wall material of the microcapsule, so that the prepared microcapsule has a good spherical shape, a small particle size, good dispersibility and high pH sensitivity, forms a denser surface under an acidic condition to effectively protect probiotics, and can meet requirements for subsequent in vivo animal evaluations.

Abstract: A method of fluorescence imaging is disclosed that uses a non-labeled fluorescent microsphere comprising a primary amine polymer, wherein the microsphere does not contain an additional fluorescent substance, and wherein at least one primary amine group in the primary amine polymer has the structure of —N?R—, in which R is a residue after the reaction of an aldehyde-type cross-linking substance, and the other primary amine groups have the structure of —NH2. The fluorescence color of the microspheres can be adjusted by selecting different aldehyde-type cross-linking substances or combinations, and the fluorescence intensity of the microspheres can be controlled not only by the addition of the aldehyde-type cross-linking substances and the time of the cross-linking reaction, but also by adjusting the diameters of the microspheres.

Abstract: The invention discloses the microspheres comprising the following structure in the composition thereof and the uses as tracers and fluorescent standard calibration products. wherein, groups A, B and C are linked to hydrocarbon chain , and at least one of A, B and C has the structure of —N?R—, in which R is a residue after the reaction of an aldehyde-type cross-linking substance, and the others of A, B and C are —NH2 structure. The microspheres comprising the above structure have an obvious phenomenon of self-fluorescence, and the fluorescence output of each microsphere is significantly larger than the fluorescence outputted by the microsphere embedded with fluorescent substances. The microspheres have toleration to light-bleach and the dependency on other environments without modifying the surface property of the microspheres themselves. The invention further discloses the preparation method of the above fluorescent microspheres.