Accurate and high throughput cell sorting is a critical enabling technology in molecular and cellular biology, biotechnology, and medicine. While conventional methods can provide high efficiency ...sorting in short timescales, advances in microfluidics have enabled the realization of miniaturized devices offering similar capabilities that exploit a variety of physical principles. We classify these technologies as either active or passive. Active systems generally use external fields (e.g., acoustic, electric, magnetic, and optical) to impose forces to displace cells for sorting, whereas passive systems use inertial forces, filters, and adhesion mechanisms to purify cell populations. Cell sorting on microchips provides numerous advantages over conventional methods by reducing the size of necessary equipment, eliminating potentially biohazardous aerosols, and simplifying the complex protocols commonly associated with cell sorting. Additionally, microchip devices are well suited for parallelization, enabling complete lab-on-a-chip devices for cellular isolation, analysis, and experimental processing. In this review, we examine the breadth of microfluidic cell sorting technologies, while focusing on those that offer the greatest potential for translation into clinical and industrial practice and that offer multiple, useful functions. We organize these sorting technologies by the type of cell preparation required (i.e., fluorescent label-based sorting, bead-based sorting, and label-free sorting) as well as by the physical principles underlying each sorting mechanism.
Macrophages play a key role in defending against foreign pathogens, healing wounds, and regulating tissue homeostasis. Driving this versatility is their phenotypic plasticity, which enables ...macrophages to respond to subtle cues in tightly coordinated ways. However, when this coordination is disrupted, macrophages can aid the progression of numerous diseases, including cancer, cardiovascular disease, and autoimmune disease. The central link between these disorders is aberrant macrophage polarization, which misguides their functional programs, secretory products, and regulation of the surrounding tissue microenvironment. As a result of their important and deterministic roles in both health and disease, macrophages have gained considerable attention as targets for drug delivery. Here, we discuss the role of macrophages in the initiation and progression of various inflammatory diseases, summarize the leading drugs used to regulate macrophages, and review drug delivery systems designed to target macrophages. We emphasize strategies that are approved for clinical use or are poised for clinical investigation. Finally, we provide a prospectus of the future of macrophage-targeted drug delivery systems.
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Materials for Immunotherapy Shields, C. Wyatt; Wang, Lily Li‐Wen; Evans, Michael A. ...
Advanced materials (Weinheim),
04/2020, Volume:
32, Issue:
13
Journal Article
Peer reviewed
Breakthroughs in materials engineering have accelerated the progress of immunotherapy in preclinical studies. The interplay of chemistry and materials has resulted in improved loading, targeting, and ...release of immunomodulatory agents. An overview of the materials that are used to enable or improve the success of immunotherapies in preclinical studies is presented, from immunosuppressive to proinflammatory strategies, with particular emphasis on technologies poised for clinical translation. The materials are organized based on their characteristic length scale, whereby the enabling feature of each technology is organized by the structure of that material. For example, the mechanisms by which i) nanoscale materials can improve targeting and infiltration of immunomodulatory payloads into tissues and cells, ii) microscale materials can facilitate cell‐mediated transport and serve as artificial antigen‐presenting cells, and iii) macroscale materials can form the basis of artificial microenvironments to promote cell infiltration and reprogramming are discussed. As a step toward establishing a set of design rules for future immunotherapies, materials that intrinsically activate or suppress the immune system are reviewed. Finally, a brief outlook on the trajectory of these systems and how they may be improved to address unsolved challenges in cancer, infectious diseases, and autoimmunity is presented.
Immunotherapy has established a new paradigm for the management and treatment of diseases, leading to numerous clinical breakthroughs. The means by which materials have helped overcome critical barriers associated with emerging immunotherapies are reviewed, and new opportunities for their continued advancement are discussed.
Adoptive cell transfers have emerged as a disruptive approach to treat disease in a manner that is more specific than using small-molecule drugs; however, unlike traditional drugs, cells are living ...entities that can alter their function in response to environmental cues. In the present study, we report an engineered particle referred to as a "backpack" that can robustly adhere to macrophage surfaces and regulate cellular phenotypes in vivo. Backpacks evade phagocytosis for several days and release cytokines to continuously guide the polarization of macrophages toward antitumor phenotypes. We demonstrate that these antitumor phenotypes are durable, even in the strongly immunosuppressive environment of a murine breast cancer model. Conserved phenotypes led to reduced metastatic burdens and slowed tumor growths compared with those of mice treated with an equal dose of macrophages with free cytokine. Overall, these studies highlight a new pathway to control and maintain phenotypes of adoptive cellular immunotherapies.
In the last two decades, advances in micro‐ and nanofabrication have enabled the development of a wide variety of active or “self‐propelling” microparticles, which convert energy from their ...environment into directed motion. While these autonomous entities have shown promise for efficient locomotion on the microscale, their practical utility remains unrealized due to their inability to perform multiple useful tasks on demand. From an engineering perspective, the active particle behavior can be encoded on an individual level by tailoring key design elements such as shape, polarizability, surface pattern, and bulk functionality. This feature article focusses on active particles powered by electric and magnetic fields, as these sources of energy allow the particles to: (1) move in several phenomenologically unique ways, (2) respond in a reliable manner to the field parameters, and (3) interact synergistically to enable multiple functions. It is hypothesized how future generations of such particles may remotely harvest and transduce energy to perform several useful tasks such as biosensing and delivering drugs. As a step toward realizing such particles, several new types of active particles are demonstrated. Finally, a perspective on the future directions of this emerging field is provided by discussing current challenges, potential applications as well as future opportunities.
Engineered active particles exist outside of equilibrium by harvesting energy to self‐propel. Such particles can in the future perform complex operations such as delivering drugs to remote areas in the body. The use of electric and magnetic fields allows these particles to move in complex trajectories by independently propelling and steering them, and powering additional functionalities.
Approaches to safely and effectively augment cellular functions without compromising the inherent biological properties of the cells, especially through the integration of biologically labile ...domains, remain of great interest. Here, a versatile strategy to assemble biologically active nanocomplexes, including proteins, DNA, mRNA, and even viral carriers, on cellular surfaces to generate a cell‐based hybrid system referred to as “Cellnex” is established. This strategy can be used to engineer a wide range of cell types used in adoptive cell transfers, including erythrocytes, macrophages, NK cells, T cells, etc. Erythrocytenex can enhance the delivery of cargo proteins to the lungs in vivo by 11‐fold as compared to the free cargo counterpart. Biomimetic microfluidic experiments and modeling provided detailed insights into the targeting mechanism. In addition, Macrophagenex is capable of enhancing the therapeutic efficiency of anti‐PD‐L1 checkpoint inhibitors in vivo. This simple and adaptable approach may offer a platform for the rapid generation of complex cellular systems.
A simple, adaptable, polyphenol‐based molecular engineering platform “Cellnex” is reported as a rapid and efficient approach to functionalize cell surfaces with biomolecules. This platform enables the customized engineering of a wide range of mammalian cells with diverse classes of biomolecules. Cells engineered with this approach are capable of achieving targeted biomolecule delivery and improving the biological outcomes of respective biomolecules.
Remotely powered microrobots are proposed as next‐generation vehicles for drug delivery. However, most microrobots swim with linear trajectories and lack the capacity to robustly adhere to soft ...tissues. This limits their ability to navigate complex biological environments and sustainably release drugs at target sites. In this work, bubble‐based microrobots with complex geometries are shown to efficiently swim with non‐linear trajectories in a mouse bladder, robustly pin to the epithelium, and slowly release therapeutic drugs. The asymmetric fins on the exterior bodies of the microrobots induce a rapid rotational component to their swimming motions of up to ≈150 body lengths per second. Due to their fast speeds and sharp fins, the microrobots can mechanically pin themselves to the bladder epithelium and endure shear stresses commensurate with urination. Dexamethasone, a small molecule drug used for inflammatory diseases, is encapsulated within the polymeric bodies of the microrobots. The sustained release of the drug is shown to temper inflammation in a manner that surpasses the performance of free drug controls. This system provides a potential strategy to use microrobots to efficiently navigate large volumes, pin at soft tissue boundaries, and release drugs over several days for a range of diseases.
Bubble‐containing microrobots with asymmetric fins propel within a mouse bladder at ultrafast speeds. Due to their fast speeds and sharp fins, microrobots can mechanically pin themselves to the bladder epithelium. The sustained release of drugs from the microrobots tempers inflammatory phenotypes of immune cells in a manner that surpasses the performance of the free drug.
Lab-on-a-chip tools have played a pivotal role in advancing modern biology and medicine. A key goal in this field is to precisely transport single particles and cells to specific locations on a chip ...for quantitative analysis. To address this large and growing need, magnetophoretic circuits have been developed in the last decade to manipulate a large number of single bioparticles in a parallel and highly controlled manner. Inspired by electrical circuits, magnetophoretic circuits are composed of passive and active circuit elements to offer commensurate levels of control and automation for transporting individual bioparticles. These specifications make them unique compared to other technologies in addressing crucial bioanalytical applications and answering fundamental questions buried in highly heterogeneous cell populations. In this comprehensive review, we describe key theoretical considerations for manufacturing and simulating magnetophoretic circuits. We provide a detailed tutorial for operating magnetophoretic devices containing different circuit elements (e.g., conductors, diodes, capacitors, and transistors). Finally, we provide a critical comparison of the utility of these devices to other microchip-based platforms for cellular manipulation, and discuss how they may address unmet needs in single-cell biology and medicine.
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Microrobots are being explored for biomedical applications, such as drug delivery, biological cargo transport, and minimally invasive surgery. However, current efforts largely focus on ...proof-of-concept studies with nontranslatable materials through a "
" approach, limiting the potential for clinical adaptation. While these proof-of-concept studies have been key to advancing microrobot technologies, we believe that the distinguishing capabilities of microrobots will be most readily brought to patient bedsides through a "
" approach, which involves focusing on unsolved problems to inform the design of microrobots with practical capabilities. As outlined below, we propose that the clinical translation of microrobots will be accelerated by a judicious choice of target applications, improved delivery considerations, and the rational selection of translation-ready biomaterials, ultimately reducing patient burden and enhancing the efficacy of therapeutic drugs for difficult-to-treat diseases.
Combination chemotherapy is the leading clinical option for cancer treatment. The current approach to designing drug combinations includes in vitro optimization to maximize drug cytotoxicity and/or ...synergistic drug interactions. However, in vivo translatability of drug combinations is complicated by the disparities in drug pharmacokinetics and activity. In vitro cellular assays also fail to represent the immune response that can be amplified by chemotherapy when dosed appropriately. Using three common chemotherapeutic drugs, gemcitabine (GEM), irinotecan (IRIN), and a prodrug form of 5-flurouracil (5FURW), paired with another common drug and immunogenic cell death inducing agent, doxorubicin (DOX), we sought to determine the in vitro parameters that predict the in vivo outcomes of drug combinations in the highly aggressive orthotopic 4T1 murine breast cancer model. With liposomal encapsulation of each drug pair, we enabled uniform drug pharmacokinetics across the drug combinations, thus allowing us to study the inherent benefits of the drug pairs and compare them to DOX liposomes representative of DOXIL®. Surprisingly, the Hill coefficient (HC) of the in vitro dose-response Hill equation provided a better prediction of in vivo efficacy than drug IC50 or combination index. GEM/DOX liposomes exhibited a high HC in vitro and an increase in M1/M2 macrophage ratio in vivo. Hence, GEM/DOX liposomes were further investigated in a long-term survival study and compared against doxorubicin liposomes and gemcitabine liposomes. The GEM/DOX liposome-treated group had the longest median survival time, double that of the DOX liposome-treated group and 3.4-fold greater than that of the untreated controls. Our studies outline the development of a more efficacious formulation than clinically representative liposomal doxorubicin for breast cancer treatment and presents a novel strategy for designing cancer drug combinations.
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•Nanoparticles containing chemotherapeutic drug combinations suffer from unpredictable in vitro to in vivo translation.•In vitro assays also fail to capture the extremely nuanced immune response to chemotherapy in the tumor microenvironment.•Different liposomal drug combinations were designed based on in vitro parameters and studied for a tumor immune response.•Drug combinations with high in vitro dose-response Hill Coefficients showed the strongest correlation with tumor response.
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