Hierarchically porous composite microparticles from microfluidics for controllable drug delivery

Advancing cancer treatments: The role of oligonucleotide-based therapies in driving progress

Although recent advancements in cancer immunology have resulted in the approval of numerous immunotherapies, minimal progress has been observed in addressing hard-to-treat cancers. In this context, therapeutic oligonucleotides, including interfering RNAs, antisense oligonucleotides, aptamers, and DNAzymes, have gained a central role in cancer therapeutic approaches due to their capacity to regulate gene expression and protein function with reduced toxicity compared with conventional chemotherapeutics. Nevertheless, systemic administration of naked oligonucleotides faces many extra- and intracellular challenges that can be overcome by using effective delivery systems. Thus, viral and non-viral carriers can improve oligonucleotide stability and intracellular uptake, enhance tumor accumulation, and increase the probability of endosomal escape while minimizing other adverse effects. Therefore, gaining more insight into fundamental mechanisms of actions of various oligonucleotides and the challenges posed by naked oligonucleotide administration, this article provides a comprehensive review of the recent progress on oligonucleotide delivery systems and an overview of completed and ongoing cancer clinical trials that can shape future oncological treatments.

Synthetic Cells from Droplet-Based Microfluidics for Biosensing and Biomedical Applications

Synthetic cells function as biological mimics of natural cells by mimicking salient features of cells such as metabolism, response to stimuli, gene expression, direct metabolism, and high stability. Droplet-based microfluidic technology presents the opportunity for encapsulating biological functional components in uni-lamellar liposome or polymer droplets. Verified by its success in the fabrication of synthetic cells, microfluidic technology is widely replacing conventional labor-intensive, expensive, and sophisticated techniques justified by its ability to miniaturize and perform batch production operations. In this review, an overview of recent research on the preparation of synthetic cells through droplet-based microfluidics is provided. Different synthetic cells including lipid vesicles (liposome), polymer vesicles (polymersome), coacervate microdroplets, and colloidosomes, are systematically discussed. Efforts are then made to discuss the design of a variety of microfluidic chips for synthetic cell preparation since the combination of microfluidics with bottom-up synthetic biology allows for reproductive and tunable construction of batches of synthetic cell models from simple structures to higher hierarchical structures. The recent advances aimed at exploiting them in biosensors and other biomedical applications are then discussed. Finally, some perspectives on the challenges and future developments of synthetic cell research with microfluidics for biomimetic science and biomedical applications are provided.

Recent Advances in Functional Hydrogel for Repair of Abdominal Wall Defects: A Review

The abdominal wall plays a crucial role in safeguarding the internal organs of the body, serving as an essential protective barrier. Defects in the abdominal wall are common due to surgery, infection, or trauma. Complex defects have limited self-healing capacity and require external intervention. Traditional treatments have drawbacks, and biomaterials have not fully achieved the desired outcomes. Hydrogel has emerged as a promising strategy that is extensively studied and applied in promoting tissue regeneration by filling or repairing damaged tissue due to its unique properties. This review summarizes the five prominent properties and advances in using hydrogels to enhance the healing and repair of abdominal wall defects: (a) good biocompatibility with host tissues that reduces adverse reactions and immune responses while supporting cell adhesion migration proliferation; (b) tunable mechanical properties matching those of the abdominal wall that adapt to normal movement deformations while reducing tissue stress, thereby influencing regulating cell behavior tissue regeneration; (c) drug carriers continuously delivering drugs and bioactive molecules to sites optimizing healing processes enhancing tissue regeneration; (d) promotion of cell interactions by simulating hydrated extracellular matrix environments, providing physical support, space, and cues for cell migration, adhesion, and proliferation; (e) easy manipulation and application in surgical procedures, allowing precise placement and close adhesion to the defective abdominal wall, providing mechanical support. Additionally, the advances of hydrogels for repairing defects in the abdominal wall are also mentioned. Finally, an overview is provided on the current obstacles and constraints faced by hydrogels, along with potential prospects in the repair of abdominal wall defects.

Microfluidics-derived hierarchical microparticles for the delivery of dienogest for localized endometriosis therapy

Drug therapy is one of the most important strategies for treating gynecological diseases. Local drug delivery is promising for achieving optimal regional drug exposure, considering the complex anatomy and dynamic environment of the upper genital tract. Here, we present microparticle-based microcarriers with a hierarchical structure for localized dienogest (DNG) delivery and endometriosis treatment. The microparticles were fabricated by microfluidics and consisted of photo-crosslinked bovine serum albumin hydrogel particles (D@P-B MPs) encapsulating DNG-loaded PLGA (poly lactic-co-glycolic acid) microspheres. Such design enables the microparticles to have sustained release capacity and cell adhesion ability. Based on this, the microparticles were applied for the treatment of peritoneal endometriosis through intraperitoneal injection. The performance of the microparticles in inhibiting the growth of ectopic lesions as well as their anti-inflammatory, anti-angiogenesis, and pelvic pain-relieving effects are well demonstrated in vivo. These findings indicate that the present hierarchical microparticles are good candidates for localized treatment of endometriosis and are promising for the management of gynecological diseases. STATEMENT OF SIGNIFICANCE: We prepared photo-crosslinked bovine serum albumin hydrogel particles (D@P-B MPs) encapsulating DNG-loaded PLGA microspheres using microfluidic electrospray. Such hierarchical structure provided multiple functions of the particles as drug carriers. The hierarchical microparticles not only supported the sustained release of drugs but also provided adhesion to human ectopic endometrial stromal cells. The hierarchical microparticles represented a localized treatment method for endometriosis and is promising for the management of gynecological diseases.

Hydrogel Microparticles for Bone Regeneration

Hydrogel microparticles (HMPs) stand out as promising entities in the realm of bone tissue regeneration, primarily due to their versatile capabilities in delivering cells and bioactive molecules/drugs. Their significance is underscored by distinct attributes such as injectability, biodegradability, high porosity, and mechanical tunability. These characteristics play a pivotal role in fostering vasculature formation, facilitating mineral deposition, and contributing to the overall regeneration of bone tissue. Fabricated through diverse techniques (batch emulsion, microfluidics, lithography, and electrohydrodynamic spraying), HMPs exhibit multifunctionality, serving as vehicles for drug and cell delivery, providing structural scaffolding, and functioning as bioinks for advanced 3D-printing applications. Distinguishing themselves from other scaffolds like bulk hydrogels, cryogels, foams, meshes, and fibers, HMPs provide a higher surface-area-to-volume ratio, promoting improved interactions with the surrounding tissues and facilitating the efficient delivery of cells and bioactive molecules. Notably, their minimally invasive injectability and modular properties, offering various designs and configurations, contribute to their attractiveness for biomedical applications. This comprehensive review aims to delve into the progressive advancements in HMPs, specifically for bone regeneration. The exploration encompasses synthesis and functionalization techniques, providing an understanding of their diverse applications, as documented in the existing literature. The overarching goal is to shed light on the advantages and potential of HMPs within the field of engineering bone tissue.

Application of colloidal photonic crystals in study of organoids

As alternative disease models, other than 2D cell lines and patient-derived xenografts, organoids have preferable in vivo physiological relevance. However, both endogenous and exogenous limitations impede the development and clinical translation of these organoids. Fortunately, colloidal photonic crystals (PCs), which benefit from favorable biocompatibility, brilliant optical manipulation, and facile chemical decoration, have been applied to the engineering of organoids and have achieved the desirable recapitulation of the ECM niche, well-defined geometrical onsets for initial culture, in situ multiphysiological parameter monitoring, single-cell biomechanical sensing, and high-throughput drug screening with versatile functional readouts. Herein, we review the latest progress in engineering organoids fabricated from colloidal PCs and provide inputs for future research.

Recent Progress of Droplet Microfluidic Emulsification Based Synthesis of Functional Microparticles

The remarkable control function over the functional material formation process enabled by droplet microfluidic emulsification approaches can lead to the efficient and one-step encapsulation of active substances in microparticles, with the microparticle characteristics well regulated. In comparison to the conventional fabrication methods, droplet microfluidic technology can not only construct microparticles with various shapes, but also provide excellent templates, which enrich and expand the application fields of microparticles. For instance, intersection with disciplines in pharmacy, life sciences, and others, modifying the structure of microspheres and appending functional materials can be completed in the preparation of microparticles. The as-prepared polymer particles have great potential in a wide range of applications for chemical analysis, heavy metal adsorption, and detection. This review systematically introduces the devices and basic principles of particle preparation using droplet microfluidic technology and discusses the research of functional microparticle formation with high monodispersity, involving a plethora of types including spherical, nonspherical, and Janus type, as well as core-shell, hole-shell, and controllable multicompartment particles. Moreover, this review paper also exhibits a critical analysis of the current status and existing challenges, and outlook of the future development in the emerging fields has been discussed.

Biomedical applications of PLGA nanoparticles in nanomedicine: advances in drug delivery systems and cancer therapy

INTRODUCTION

During the last decades, the ever-increasing proportion of patients with cancer has been led to serious concerns worldwide. Therefore, the development and use of novel pharmaceuticals, like nanoparticles (NPs)-based drug delivery systems (DDSs), can be potentially effective in cancer therapy.

AREA COVERED

Poly lactic-co-glycolic acid (PLGA) NPs, as a kind of bioavailable, biocompatible, and biodegradable polymers, have approved by the Food and Drug Administration (FDA) for some biomedical and pharmaceutical applications. PLGA is comprised of lactic acid (LA) and glycolic acid (GA) and their ratio could be controlled during various syntheses and preparation approaches. LA/GA ratio determines the stability and degradation time of PLGA; lower content of GA results in fast degradation. There are several approaches for preparing PLGA NPs that can affect their various aspects, such as size, solubility, stability, drug loading, pharmacokinetics, and pharmacodynamics, and so on.

EXPERT OPINION

These NPs have indicated the controlled and sustained drug release in the cancer site and can use in passive and active (via surface modification) DDSs. This review aims to provide an overview of PLGA NPs, their preparation approach and physicochemical aspects, drug release mechanism and the cellular fate, DDSs for efficient cancer therapy, and status in the pharmaceutical industry and nanomedicine.

Porous Structural Microfluidic Device for Biomedical Diagnosis: A Review

Microfluidics has recently received more and more attention in applications such as biomedical, chemical and medicine. With the development of microelectronics technology as well as material science in recent years, microfluidic devices have made great progress. Porous structures as a discontinuous medium in which the special flow phenomena of fluids lead to their potential and special applications in microfluidics offer a unique way to develop completely new microfluidic chips. In this article, we firstly introduce the fabrication methods for porous structures of different materials. Then, the physical effects of microfluid flow in porous media and their related physical models are discussed. Finally, the state-of-the-art porous microfluidic chips and their applications in biomedicine are summarized, and we present the current problems and future directions in this field.

Recent Advances in Drug Delivery System Fabricated by Microfluidics for Disease Therapy

Traditional drug therapy faces challenges such as drug distribution throughout the body, rapid degradation and excretion, and extensive adverse reactions. In contrast, micro/nanoparticles can controllably deliver drugs to target sites to improve drug efficacy. Unlike traditional large-scale synthetic systems, microfluidics allows manipulation of fluids at the microscale and shows great potential in drug delivery and precision medicine. Well-designed microfluidic devices have been used to fabricate multifunctional drug carriers using stimuli-responsive materials. In this review, we first introduce the selection of materials and processing techniques for microfluidic devices. Then, various well-designed microfluidic chips are shown for the fabrication of multifunctional micro/nanoparticles as drug delivery vehicles. Finally, we describe the interaction of drugs with lymphatic vessels that are neglected in organs-on-chips. Overall, the accelerated development of microfluidics holds great potential for the clinical translation of micro/nanoparticle drug delivery systems for disease treatment.

Multicompartmental Microcapsules for Enzymatic Cascade Reactions Prepared through Gas Shearing and Surface Gelation

Inspired by the structure of eukaryotic cells, multicompartmental microcapsules have gained increasing attention. However, challenges remain in the fabrication of "all-aqueous" (i.e., oil-free) microcapsules composed of accurately adjustable hierarchical compartments. This study reports on multicompartmental microcapsules with an innovative architecture. While multicompartmental cores of the microcapsules were fabricated through gas shearing, a shell was applied on the cores through surface gelation of alginate. Different from traditional multicompartmental microcapsules, thus obtained microcapsules have well-segregated compartments while the universal nature of the surface-gelation method allows us to finely tune the shell thicknesses of the microcapsules. The microcapsules are highly stable and cytocompatible and allow repeated enzymatic cascade reactions, which might make them of interest for complex biocatalysis or for mimicking physiological processes.

Recent Development of Drug Delivery Systems through Microfluidics: From Synthesis to Evaluation

Conventional drug administration usually faces the problems of degradation and rapid excretion when crossing many biological barriers, leading to only a small amount of drugs arriving at pathological sites. Therapeutic drugs delivered by drug delivery systems to the target sites in a controlled manner greatly enhance drug efficacy, bioavailability, and pharmacokinetics with minimal side effects. Due to the distinct advantages of microfluidic techniques, microfluidic setups provide a powerful tool for controlled synthesis of drug delivery systems, precisely controlled drug release, and real-time observation of drug delivery to the desired location at the desired rate. In this review, we present an overview of recent advances in the preparation of nano drug delivery systems and carrier-free drug delivery microfluidic systems, as well as the construction of in vitro models on-a-chip for drug efficiency evaluation of drug delivery systems. We firstly introduce the synthesis of nano drug delivery systems, including liposomes, polymers, and inorganic compounds, followed by detailed descriptions of the carrier-free drug delivery system, including micro-reservoir and microneedle drug delivery systems. Finally, we discuss in vitro models developed on microfluidic devices for the evaluation of drug delivery systems, such as the blood–brain barrier model, vascular model, small intestine model, and so on. The opportunities and challenges of the applications of microfluidic platforms in drug delivery systems, as well as their clinical applications, are also discussed.

Droplet microfluidics-based biomedical microcarriers

Droplet microfluidic technology provides a new platform for controllable generation of microdroplets and droplet-derived materials. In particular, because of the ability in high-throughput production and accurate control of the size, structure, and function of these materials, droplet microfluidics presents unique advantages in the preparation of functional microcarriers, i.e., microsized liquid containers or solid particles that serve as substrates of biomolecules or cells. These microcarriers could be extensively applied in the areas of cell culture, tissue engineering, and drug delivery. In this review, we focus on the fabrication of microcarriers from droplet microfluidics, and discuss their applications in the biomedical field. We start with the basic principle of droplet microfluidics, including droplet generation regimes and its control methods. We then introduce the fabrication of biomedical microcarriers based on single, double, and multiple emulsion droplets, and emphasize the various applications of microcarriers in biomedical field, especially in 3D cell culture, drug development and biomedical detection. Finally, we conclude this review by discussing the limitations and challenges of droplet microfluidics in preparing microcarriers. STATEMENT OF SIGNIFICANCE: Because of its precise control and high throughput, droplet microfluidics has been employed to generate functional microcarriers, which have been widely used in the areas of drug development, tissue engineering, and regenerative medicine. This review is significant because it emphasizes recent progress in research on droplet microfluidics in the preparation and application of biomedical microcarriers. In addition, this review suggests research directions for the future development of biomedical microcarriers based on droplet microfluidics by presenting existing shortcomings and challenges.

Recent Advances of Microfluidic Platforms for Controlled Drug Delivery in Nanomedicine

Nanomedicine drug delivery systems hold great potential for the therapy of many diseases, especially cancer. However, the controlled drug delivery systems of nanomedicine bring many challenges to clinical practice. These difficulties can be attributed to the high batch-to-batch variations and insufficient production rate of traditional preparation methods, as well as a lack of technology for fast screening of nanoparticulate drug delivery structures with high correlation to in vivo tests. These problems may be addressed through microfluidic technology. Microfluidics, for example, can not only produce nanoparticles in a well-controlled, reproducible, and high-throughput manner, but it can also continuously create three-dimensional environments to mimic physiological and/or pathological processes. This overview gives a top-level view of the microfluidic devices advanced to put together nanoparticulate drug delivery systems, including drug nanosuspensions, polymer nanoparticles, polyplexes, structured nanoparticles and therapeutic nanoparticles. Additionally, highlighting the current advances of microfluidic systems in fabricating the more and more practical fashions of the in vitro milieus for fast screening of nanoparticles was reviewed. Overall, microfluidic technology provides a promising technique to boost the scientific delivery of nanomedicine and nanoparticulate drug delivery systems. Nonetheless, digital microfluidics with droplets and liquid marbles is the answer to the problems of cumbersome external structures, in addition to the rather big pattern volume. As the latest work is best at the proof-of-idea of liquid-marble-primarily based on totally virtual microfluidics, computerized structures for developing liquid marble, and the controlled manipulation of liquid marble, including coalescence and splitting, are areas of interest for bringing this platform toward realistic use.

Microfluidics for Drug Development: From Synthesis to Evaluation

Drug development is a long process whose main content includes drug synthesis, drug delivery, and drug evaluation. Compared with conventional drug development procedures, microfluidics has emerged as a revolutionary technology in that it offers a miniaturized and highly controllable environment for bio(chemical) reactions to take place. It is also compatible with analytical strategies to implement integrated and high-throughput screening and evaluations. In this review, we provide a comprehensive summary of the entire microfluidics-based drug development system, from drug synthesis to drug evaluation. The challenges in the current status and the prospects for future development are also discussed. We believe that this review will promote communications throughout diversified scientific and engineering communities that will continue contributing to this burgeoning field.

Droplet Microfluidics for Tumor Drug-Related Studies and Programmable Artificial Cells

Anticancer drug development is a crucial step toward cancer treatment, that requires realistic predictions of malignant tissue development and sophisticated drug delivery. Tumors often acquire drug resistance and drug efficacy, hence cannot be accurately predicted in 2D tumor cell cultures. On the other hand, 3D cultures, including multicellular tumor spheroids (MCTSs), mimic the in vivo cellular arrangement and provide robust platforms for drug testing when grown in hydrogels with characteristics similar to the living body. Microparticles and liposomes are considered smart drug delivery vehicles, are able to target cancerous tissue, and can release entrapped drugs on demand. Microfluidics serve as a high-throughput tool for reproducible, flexible, and automated production of droplet-based microscale constructs, tailored to the desired final application. In this review, it is described how natural hydrogels in combination with droplet microfluidics can generate MCTSs, and the use of microfluidics to produce tumor targeting microparticles and liposomes. One of the highlights of the review documents the use of the bottom-up construction methodologies of synthetic biology for the formation of artificial cellular assemblies, which may additionally incorporate both target cancer cells and prospective drug candidates, as an integrated "droplet incubator" drug assay platform.

Emerging Functional Biomaterials as Medical Patches

Medical patches have been widely explored and applied in various medical fields, especially in wound healing, tissue engineering, and other biomedical areas. Benefiting from emerging biomaterials and advanced manufacturing technologies, great achievements have been made on medical patches to evolve them into a multifunctional medical device for diverse health-care purposes, thus attracting extensive attention and research interest. Here, we provide up-to-date research concerning emerging functional biomaterials as medical patches. An overview of the various approaches to construct patches with micro- and nanoarchitecture is presented and summarized. We then focus on the applications, especially the biomedical applications, of the medical patches, including wound healing, drug delivery, and real-time health monitoring. The challenges and prospects for the future development of the medical patches are also discussed.

Introduction of Enzyme-Responsivity in Biomaterials to Achieve Dynamic Reciprocity in Cell-Material Interactions

Much effort has been made in the development of biomaterials that synthetically mimic the dynamics of the natural extracellular matrix in tissues. Most of these biomaterials specifically interact with cells, but lack the ability to adapt and truly communicate with the cellular environment. Communication between biomaterials and cells is achieved by the development of various materials with enzyme-responsive moieties in order to respond to cellular cues. In this perspective, we discuss different enzyme-responsive systems, from surfaces to supramolecular assemblies. Additionally, we highlight their further prospects in order to create, inspired by nature, fully autonomous adaptive biomaterials that display dynamic reciprocal behavior. This Perspective shows new strategies for the development of biomaterials that may find broad utility in regenerative medicine applications, from scaffolds for tissue engineering to systems for controlled drug delivery.

NIR responsive AuNR/pNIPAM/PEGDA inverse opal hydrogel microcarriers for controllable drug delivery

A novel inverse opal microcarrier with both NIR-controlled release and visual color changes for drug delivery.

Spontaneous droplet generation via surface wetting

A surface wetting-driven droplet generation microfluidic chip was developed, and could produce droplets spontaneously once adding a drop of oil and an aqueous sample on the chip without any power source and equipment. The chip is simply composed of three drilled holes connected by a single microchannel. The aqueous sample dropped in the middle hole could be converged and segmented into monodispersed droplets spontaneously by preloading oil in the side hole, and then flow into the other side hole through the microchannel. To address the high throughput and stability in practical applications, a siphon pump was further integrated into the microfluidic chip by simply connecting oil-filled tubing also acting as a collector. In this way, droplets can be generated spontaneously with a high uniformity (CV < 3.5%) and adjustable size (30-80 μm). Higher throughput (280 Hz) and multi-sample emulsification are achieved by parallel integration of a multi-channel structure. Based on that, the microfluidic chip was used as the droplet generator for the ddPCR to absolutely quantify S. mutans DNA. This is the first time that the feasibility of droplet generation driven only by oil wettability on hydrophobic surfaces is demonstrated. It offers great opportunity for self-sufficient and portable W/O droplet generation in biomedical samples, thus holding the potential for point-of-care testing (POCT).

Microfluidic Generation of Nanomaterials for Biomedical Applications

As nanomaterials (NMs) possess attractive physicochemical properties that are strongly related to their specific sizes and morphologies, they are becoming one of the most desirable components in the fields of drug delivery, biosensing, bioimaging, and tissue engineering. By choosing an appropriate methodology that allows for accurate control over the reaction conditions, not only can NMs with high quality and rapid production rate be generated, but also designing composite and efficient products for therapy and diagnosis in nanomedicine can be realized. Recent evidence implies that microfluidic technology offers a promising platform for the synthesis of NMs by easy manipulation of fluids in microscale channels. In this Review, a comprehensive set of developments in the field of microfluidics for generating two main classes of NMs, including nanoparticles and nanofibers, and their various potentials in biomedical applications are summarized. Furthermore, the major challenges in this area and opinions on its future developments are proposed.

Nanostructured lipid carrier delivering chlorins e6 as in situ dendritic cell vaccine for immunotherapy of gastric cancer

The recent scientific progress has shown the promising effect of the vaccine in immunotherapy of cancer, which relies on the antigen processing/presentation capability of dendritic cells (DCs). As a result, cancer vaccines targeting DC, which also named as DC vaccine, was a hot-spot in vaccine development. Herein, a nanostructured lipid carrier (NLC) was employed to load chlorin e6 (Ce6) to serve as a potential in situ DC vaccine (NLC/Ce6) for effective immunotherapy of gastric cancer. Taking advantage of the photodynamic effect of Ce6 to generate reactive oxygen species (ROS) under laser irradiation, the NLC/Ce6 was able to trigger cell death and expose tumor-associated antigen (TAA). Moreover, mimicking the natural inflammatory response, the ROS can also recruit the DC for the effective processing/presentation of the in situ exposed TAA. As expected, we observed strong capability DC vaccination efficacy of this platform to effectively inhibit the growth of both primary and distant gastric tumors.

Photoresponsive Delivery Microcarriers for Tissue Defects Repair

Intelligent responsive microcarriers have emerged as a promising class of biomaterials for therapeutic delivery and tissue regeneration, since they can respond to external stimuli and release the loaded drugs in an active manner. Among various available stimuli, near-infrared (NIR) light is particularly attractive because it can penetrate biotic tissues with sufficient intensity and minimal damage. In this work, a kind of photoresponsive delivery microcarriers (PDMs) is developed using microfluidics. The microcarriers consist of NIR-absorbing graphene oxide, thermosensitive poly(N-isopropylacrylamide), and biocompatible gelatin methacrylate. Under NIR light, the PDMs exhibit an evident volume shrinkage and effectively trigger the drug release. After the NIR light is switched off, the shrunken microcarriers return to their original size. This reversible process can be stably repeated for many cycles. An in vitro experiment demonstrates that the NIR-radiated PDMs can actively release vascular endothelial growth factors and improve the tube formation of human umbilical vein endothelial cells. The results from the in vivo experiment also show an obvious photothermal effect and superior therapeutic efficacy of these PDMs in a rat model of tissue defects. These features make the PDMs an excellent drug delivery system and represent a great potential for clinical applications in tissue repair.

Microfluidics for silica biomaterials synthesis: opportunities and challenges

The rational design and controllable synthesis of silica nanomaterials bearing unique physicochemical properties is becoming increasingly important for a variety of biomedical applications from imaging to drug delivery. Microfluidics has recently emerged as a promising platform for nanomaterial synthesis, providing precise control over particle size, shape, porosity, and structure compared to conventional batch synthesis approaches. This review summarizes microfluidics approaches for the synthesis of silica materials as well as the design, fabrication and the emerging roles in the development of new classes of functional biomaterials. We highlight the unprecedented opportunities of using microreactors in biomaterial synthesis, and assess the recent progress of continuous and discrete microreactors and the associated biomedical applications of silica materials. Finally, we discuss the challenges arising from the intrinsic properties of microfluidics reactors for inspiring future research in this field.

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.