Yuxiao Liu

Photonic Crystal Microbubbles as Suspension Barcodes

A novel suspension array was developed that uses photonic crystal (PhC) microbubbles as barcode particles. The PhC microbubbles have an outer transparent polymeric shell, a middle PhC shell, and an inner bubble core, and they were achieved by extraction-derived self-assembly of colloidal nanoparticles in semipermeable solid microcapsules. The encoded elements of the microbubbles originated from their PhC structure with a coated shell, which not only improved the stability of the codes but also provided a flexible surface for bioassays. By using multicompartmental microcapsule templates, PhC microbubbles with substantial coding levels and controllable movement could also be achieved. In addition, as the size of the encapsulated bubbles could be tailored, the overall density of the PhC microbubbles could be adjusted to match the density of a detection solution and to remain in suspension. These remarkable properties make the PhC microbubbles excellent barcode particles.

Composite core-shell microparticles from microfluidics for synergistic drug delivery

Microparticles have a demonstrated value for drug delivery systems. The attempts to develop this technology focus on the generation of featured microparticles for improving the function of the systems. Here, we present a new type ofmicroparticles with gelatinmethacrylate (GelMa) cores and poly(L-lactide-co-glycolide) (PLGA) shells for synergistic and sustained drug delivery applications. The microparticles were fabricated by using GelMa aqueous solution and PLGA oil solution as the raw materials of the microfluidic double emulsion templates, in which hydrophilic and hydrophobic actives, such as doxorubicin hydrochloride (DOX, hydrophilic) and camptothecine (CPT, hydrophobic), could be loaded respectively. As the inner cores were polymerized in the microfluidics when the double emulsions were formed, the hydrophilic actives could be trapped in the cores with high efficiency, and the rupture or fusion of the cores could be avoided during the solidification of the microparticle shells with other actives. The size and component of the microparticles can be easily and precisely adjusted by manipulating the flow solutions during the microfluidic emulsification. Because of the solid structure of the resultant microparticles, the encapsulated actives were released from the delivery systems only with the degradation of the biopolymer layers, and thus the burst release of the actives was avoided. These features of the microparticlesmake them ideal for drug delivery applications.摘要微胶囊在药物递送系统中具有重要的应用价值. 目前关于该领域的研究主要集中于开发新型微胶囊来提高药物递送系统的效率. 本 文提出了一种可协同运输和缓慢释放药物的微胶囊, 其由明胶甲基丙烯酸接枝共聚物(GelMa)内核和聚乳酸羟基乙酸共聚物(PLGA)外壳 组成. 在微胶囊的制备过程中, 使用液滴微流控技术, 将溶有盐酸阿霉素(DOX)的GelMa水溶液和溶有喜树碱(CPT)的PLGA油溶液乳化成 均匀的双乳液模板, 通过紫外固化模板内核, 通过溶剂挥发固化模板壳层. 该过程避免了乳液的破损及包裹液的流出, 因此可显著提高药 物的包裹效率. 通过调节微流控的流速, 还可精确地调节微粒的尺寸和结构. 由于所制备的微胶囊内核和外壳都为固化状态, 其包裹的活 性药物只能随着载体材料的降解而缓慢释放出来, 这就避免了其他种类药物载体所面临的药物突释现象. 本研究所开发的微胶囊的这些 优良特性使其成为药物递送系统中的理想选择.

Biomimetic enzyme cascade reaction system in microfluidic electrospray microcapsules

Biomimetic enzyme cascade reaction systems in microcapsules are developed for mimicking biocatalysis of organelles. Mimicking subcellular compartments containing enzymes in organisms is considered a promising approach to substitute for missing or lost cellular functions. Inspired by the multicompartment structures of cellular architectures, we present a novel multienzyme system based on hollow hydrogel microcapsules with flexible enzymatic inverse opal particles. Benefiting from the precise operation capability of the microfluidic electrospray and the remarkable structural color marks in the inverse opal particles, we developed a multienzyme system with controllable number, type, and spatial arrangement of the encapsulated enzymes. The hydrogel shells also could improve enzyme stability against proteolysis in the system. The multienzyme system containing alcohol oxidase and catalase could act as a cascade biocatalyst and reduce alcohol levels in media, providing an alternative antidote and prophylactic for alcohol intoxication. These features indicated that our strategy provides an ideal enzyme cascade reaction system for complex biocatalysis and biomimetic functions of some organelles or organs.

Egg Component-Composited Inverse Opal Particles for Synergistic Drug Delivery

Microparticles have a demonstrated value in drug delivery systems. The attempts to develop this technology focus on the generation of functional microparticles by using innovative but accessible materials. Here, we present egg component-composited microparticles with a hybrid inverse opal structure for synergistic drug delivery. The egg component inverse opal particles were produced by using egg yolk to negatively replicate colloid crystal bead templates. Because of their huge specific surface areas, abundant nanopores, and complex nanochannels of the inverse opal structure, the resultant egg yolk particles could be loaded with different kinds of drugs, such as hydrophobic camptothecin (CPT), by simply immersing them into the corresponding drug solutions. Attractively, additional drugs, such as the hydrophilic doxorubicin (DOX), could also be encapsulated into the particles through the secondary filling of the drug-doped egg white hydrogel into the egg yolk inverse opal scaffolds, which realized the synergistic drug delivery for the particles. It was demonstrated that the egg-derived inverse opal particles were with large quantity and lasting releasing for the CPT and DOX codelivery, and thus could significantly reduce cell viability, and enhance therapeutic efficacy in treating cancer cells. These features of the egg component-composited inverse opal microparticles indicated that they are ideal microcarriers for drug delivery.

Tofu-inspired microcarriers from droplet microfluidics for drug delivery

Microcarriers have attracted increasing interests in drug delivery. In order to develop this technique, it is prone to focus on the generation of functional particles through using simple approaches and novel but accessible materials. Here, inspired by the formation mechanism of tofu that through the mixing of soymilk and brine for cross-linking soybean proteins, we present novel soybean protein microcarriers by using microfluidic generation approach for drug delivery. Since the soybean protein droplets are generated by microfluidic emulsification method, the tofu microparticles present highly monodisperse and homogeneous morphologies. Because of the excellent biocompatibility of the soybean protein and the interconnected porous structures throughout the whole microparticles after freeze-drying, various kinds of drugs and active molecules could be absorbed and loaded in the microcarriers, which makes them versatile for drug delivery. It can be anticipated that the microfluidic-generated tofu microcarriers will have great potential in the biomedical field.

Vitamin metal–organic framework-laden microfibers from microfluidics for wound healing

Vitamin MOF-laden microfibers with alginate shells and copper- or zinc-vitamin framework cores are controllably generated by using a coaxial capillary microfluidic spinning approach. The practical value of these MOF-laden hydrogel microfibers in improving tissue wound healing has also been explored based on the antibiosis and antioxidation of the controllably released vitamins, copper ions and zinc ions of the compound materials.

Quantum-dot-encapsulated core–shell barcode particles from droplet microfluidics

The development of robust quantum dot (QD) barcode particles with specific compositions and simple identification is important to meet the demand for high-throughput assays. Here, we present a multiple-inner phase channel capillary microfluidic approach to generate novel QD-encapsulated core-shell barcode particles with distinctive features for multiplexing analysis. By using different QD dispersed polyethylene glycol diacrylate (PEGDA) solutions as the inner phases, the particles were endowed with hydrogel locked QD cores, which could maintain the dispersed status and provide distinctive identification for the particles. The shells of the barcode particles were silica nanoparticle-dispersed ethoxylated trimethylolpropane triacrylate (ETPTA) resin, which could not only improve the stability and biocompatibility of QDs, but also provide functional groups for immobilization of biomolecules due to the assembling of the silica nanoparticles on their surfaces. Due to the advanced emulsification capability of the capillary microfluidic device, double emulsion templates with multiple inner droplet phases and their resultant multicomponent QD-encapsulated core-shell barcode particles could be continually generated. These particles showed remarkable spectral coding capacity in practice, which make them ideal for biomedical applications.

Silk Fibroin Microparticles with Hollow Mesoporous Silica Nanocarriers Encapsulation for Abdominal Wall Repair

Therapeutic vascularization appears to be an effective way of repairing abdominal wall defects. Attempts to implement this treatment tend to focus on the generation of featured drug carriers with the ability effectively to encapsulate the angiogenesis-stimulating agents and control their release to maintain an appropriate concentration at the injured area. Here, a new type of composite microparticle (CM) composed of silk fibroin (SF) and hollow mesoporous silica nanocarriers (HMSNs) is presented for therapeutic agent delivery. The CMs are generated by drying microfluidic emulsion templates of HMSN-dispersed SF solution. The resultant CMs have a distinctive micro-nanostructure, in which two barriers control the drug release. The encapsulated HMSNs increase the drug-carrying capacity of the CMs, and also form the first barrier via physical absorption. The microfluidic SF microparticles not only provide a shell with excellent monodispersity and biocompatibility but also form the second barrier via efficient encapsulation. Because of these superior properties of the CMs, the loaded drugs can be delivered with a satisfactory activity at the required rate, making them ideal for implementing therapeutic vascularization and repairing abdominal wall defects.

Multifunctional Chitosan Inverse Opal Particles for Wound Healing

Wound healing is one of the most important and basic issues faced by the medical community. In this paper, we present biomass-composited inverse opal particles with a series of advanced features for drug delivery and wound healing. The particles were derived by using chitosan biomass to negatively replicate spherical colloid crystal templates. Because of the interconnected porous structures, various forms of active drugs, including fibroblast growth factor could be loaded into the void spaces of the inverse opal particles and encapsulated by temperature-responsive hydrogel. This endowed the composited particles with the capability of intelligent drug release through the relatively high temperature caused by the inflammation reaction at wound sites. Because the structural colors and characteristic reflection peaks of the composited inverse opal particles are blue-shifted during the release process, the drug delivery can be monitored in real time. It was demonstrated that the biomass-composited microcarriers were able to promote angiogenesis, collagen deposition, and granulation-tissue formation as well as reduce inflammation and thus significantly contributed to wound healing. These features point to the potential value of multifunctional biomass inverse opal particles in biomedicine.