Generation Of Protein-derived Hydrogel Microcarriers For Biomedical Applications

Microcarriers are a class of miniaturized tools that can provide support for various applications such as cell culture,drug delivery,and information coding.Compared with traditional application modes,microcarrier-based operation methods have many advantages.For example,compared with two-dimensional(2D)planar cell culture,microcarrier-based three-dimensional(3D)cell culture can more realistically simulate the growing environment of cells in vivo,enhance the cell-to-cell and cell-toenvironment interactions,promote the proliferation of cells,and contribute to building functional 3D tissue structures in vitro.For drug delivery,traditional administration methods such as oral,local,or systemic routes,often have limitations including large side effects,large fluctuations in blood concentration,and difficulty in controlling.In contrast,the microcarrier-based drug delivery method can effectively reduce the toxic and side effects of the drug,improve the utilization and stability of the drug,and facilitate the targeted transportation and controlled release,thereby greatly reducing the patient’s pain and saving drug resources.Besides,microcarriers also have broad application prospects in information encoding.Due to the fluidity and suspendability of microcarriers,the microcarrier-based encoding strategy has the characteristics of high flexibility,high sensitivity,good repeatability,and parallel assays of multiple biomolecules.In addition,through the assembly of unit components,microcarriers with diversified morphologies can also be obtained,which further increases the coding amount,thereby expanding their application range.There are many materials that can be employed to construct microcarriers.Among them,hydrogels,especially natural hydrogels,known for their good biocompatibility,sensitivity to the environment,high plasticity,rich sources,and relative economical prices,have become one of the most popular materials for constructing microcarriers.As a widely existing natural polymer,protein has attracted much attention in the field of materials science due to its unique biological activity,structural diversity and tunability.Therefore,the protein-derived hydrogels have great application values and are highly feasible for building microcarriers.Based on this,we employed protein-derived hydrogels as matrix materials,and prepared microcarriers by different methods such as microfluidics,micromolding,and construction of inverse opal templates.Moreover,the biomedical applications of these microcarriers in 3D cell culture,active molecules’ delivery,information coding,anti-counterfeiting and multiplexed bioassays were also demonstrated.The specific works are as follows:(1)Taking egg white hydrogel as the matrix material,the concentration and biocompatibility of egg white hydrogel were optimized and evaluated.A singleemulsion droplet microfluidic chip was designed and constructed,and spherical microcarriers were prepared by using the optimized hydrogel.The effects of fluid parameters on the microcarriers’ size,morphology,and monodispersity were explored.The effects of different drying methods on the surface and interior morphology of the microcarriers were also explored.This work realizes the controllable generation of natural protein-derived hydrogel microcarriers with spherical shape.(2)Generation of microcarriers with inverse opal structures was studied.First,the long-range ordered inverse opal microcarriers were prepared by using egg-component materials or gelatin methacryloyl(Gel MA)to negatively replicate the silica colloidal crystal bead templates;Second,the long-range disordered inverse opal microcarriers were prepared.In this system,the functionalized multi-shell silica nanoparticles were synthesized,and the microcarrier templates with an amorphous microstructure were formed by spraying method.The templates were then negatively replicated by the matrix material to obtain hydrogel microcarriers with long-range disordered porous microstructure.This work realizes the regulation of the micro/nano structure of the protein-derived hydrogel microcarriers.(3)Different types of dynamic micromolding devices were designed and constructed to obtain microcarriers with non-spherical morphology through onedimensional(1D)linear or 2D planar assemblies of unit components(i.e.silica colloidal crystal beads or egg white inverse opal microparticles).This assembly method can greatly expand the information storage/coding amount of microcarriers.This work has developed a high-throughput microcarrier generation method,which broadens the diversity of microcarriers’ morphology and expands the scope of their application fields.(4)Using the protein-derived hydrogel microcarriers prepared above,the biomedical applications of these microcarriers in 3D cell culture,active molecules delivery(including single drug delivery,multiple drugs delivery,and controllable oxygen delivery),information coding,anti-counterfeiting and multiplexed bioassays were studied.The functions of these microcarriers were comprehensively evaluated through in vitro and in vivo experiments.This work shows the application prospects of protein-derived hydrogel microcarriers in biomedicine.