Publications

2017
Cezar CA, Arany P, Vermillion SA, Seo BR, Vandenburgh HH, Mooney DJ. Timed Delivery of Therapy Enhances Functional Muscle Regeneration. Adv Healthc Mater. 2017;6 (19).Abstract
Cell transplantation is a promising therapeutic strategy for the treatment of traumatic muscle injury in humans. Previous investigations have typically focused on the identification of potent cell and growth factor treatments and optimization of spatial control over delivery. However, the optimal time point for cell transplantation remains unclear. Here, this study reports how myoblast and morphogen delivery timed to coincide with specific phases of the inflammatory response affects donor cell engraftment and the functional repair of severely injured muscle. Delivery of a biomaterial-based therapy timed with the peak of injury-induced inflammation leads to potent early and long-term regenerative benefits. Diminished inflammation and fibrosis, enhanced angiogenesis, and increased cell engraftment are seen during the acute stage following optimally timed treatment. Over the long term, treatment during peak inflammation leads to enhanced functional regeneration, as indicated by reduced chronic inflammation and fibrosis along with increased tissue perfusion and muscle contractile force. Treatments initiated immediately after injury or after inflammation had largely resolved provided more limited benefits. These results demonstrate the importance of appropriately timing the delivery of biologic therapy in the context of muscle regeneration. Biomaterial-based timed delivery can likely be applied to other tissues and is of potential wide utility in regenerative medicine.
Li J, Celiz AD, Yang J, Yang Q, Wamala I, Whyte W, Seo BR, Vasilyev NV, Vlassak JJ, Suo Z, et al. Tough adhesives for diverse wet surfaces. Science. 2017;357 (6349) :378-381.Abstract
Adhesion to wet and dynamic surfaces, including biological tissues, is important in many fields but has proven to be extremely challenging. Existing adhesives are cytotoxic, adhere weakly to tissues, or cannot be used in wet environments. We report a bioinspired design for adhesives consisting of two layers: an adhesive surface and a dissipative matrix. The former adheres to the substrate by electrostatic interactions, covalent bonds, and physical interpenetration. The latter amplifies energy dissipation through hysteresis. The two layers synergistically lead to higher adhesion energies on wet surfaces as compared with those of existing adhesives. Adhesion occurs within minutes, independent of blood exposure and compatible with in vivo dynamic movements. This family of adhesives may be useful in many areas of application, including tissue adhesives, wound dressings, and tissue repair.
Kwee BJ, Mooney DJ. Biomaterials for skeletal muscle tissue engineering. Curr Opin Biotechnol. 2017;47 :16-22.Abstract
Although skeletal muscle can naturally regenerate in response to minor injuries, more severe damage and myopathies can cause irreversible loss of muscle mass and function. Cell therapies, while promising, have not yet demonstrated consistent benefit, likely due to poor survival of delivered cells. Biomaterials can improve muscle regeneration by presenting chemical and physical cues to muscle cells that mimic the natural cascade of regeneration. This brief review describes strategies for muscle repair utilizing biomaterials that can provide signals to either transplanted or host muscle cells. These strategies range from approaches that utilize biomaterials alone to those that combine biomaterials with exogenous growth factors, ex vivo cultured cells, and extensive culture time.
Alvarez MM, Aizenberg J, Analoui M, Andrews AM, Bisker G, Boyden ES, Kamm RD, Karp JM, Mooney DJ, Oklu R, et al. Emerging Trends in Micro- and Nanoscale Technologies in Medicine: From Basic Discoveries to Translation. ACS Nano. 2017;11 (6) :5195-5214.Abstract
We discuss the state of the art and innovative micro- and nanoscale technologies that are finding niches and opening up new opportunities in medicine, particularly in diagnostic and therapeutic applications. We take the design of point-of-care applications and the capture of circulating tumor cells as illustrative examples of the integration of micro- and nanotechnologies into solutions of diagnostic challenges. We describe several novel nanotechnologies that enable imaging cellular structures and molecular events. In therapeutics, we describe the utilization of micro- and nanotechnologies in applications including drug delivery, tissue engineering, and pharmaceutical development/testing. In addition, we discuss relevant challenges that micro- and nanotechnologies face in achieving cost-effective and widespread clinical implementation as well as forecasted applications of micro- and nanotechnologies in medicine.
Thelin MA, Kissler S, Vigneault F, Watters AL, White D, Koshy ST, Vermillion SA, Mooney DJ, Serwold T, Ali OA. In Vivo Enrichment of Diabetogenic T Cells. Diabetes. 2017;66 (8) :2220-2229.Abstract
Dysfunctional T cells can mediate autoimmunity, but the inaccessibility of autoimmune tissues and the rarity of autoimmune T cells in the blood hinder their study. We describe a method to enrich and harvest autoimmune T cells in vivo by using a biomaterial scaffold loaded with protein antigens. In model antigen systems, we found that antigen-specific T cells become enriched within scaffolds containing their cognate antigens. When scaffolds containing lysates from an insulin-producing β-cell line were implanted subcutaneously in autoimmune diabetes-prone NOD mice, β-cell-reactive T cells homed to these scaffolds and became enriched. These T cells induced diabetes after adoptive transfer, indicating their pathogenicity. Furthermore, T-cell receptor (TCR) sequencing identified many expanded TCRs within the β-cell scaffolds that were also expanded within the pancreata of NOD mice. These data demonstrate the utility of biomaterial scaffolds loaded with disease-specific antigens to identify and study rare, therapeutically important T cells.
Lienemann PS, Rossow T, Mao AS, Vallmajo-Martin Q, Ehrbar M, Mooney DJ. Single cell-laden protease-sensitive microniches for long-term culture in 3D. Lab Chip. 2017;17 (4) :727-737.Abstract
Single cell-laden three-dimensional (3D) microgels that can serve to mimic stem cell niches in vitro, and are therefore termed microniches, can be efficiently fabricated by droplet-based microfluidics. In this technique an aqueous polymer solution along with a highly diluted cell solution is injected into a microfluidic device to create monodisperse pre-microgel droplets that are then solidified by a polymer crosslinking reaction to obtain monodisperse single cell-laden microniches. However, problems limiting this approach studying the fate of single cells include Poisson encapsulation statistics that result in mostly empty microniches, and cells egressing from the microniches during subsequent cell culture. Here, we present a strategy to bypass Poisson encapsulation statistics in synthetic microniches by selective crosslinking of only cell-laden pre-microgel droplets. Furthermore, we show that we can position cells in the center of the microniches, and that even in protease-sensitive microniches this greatly reduces cell egress. Collectively, we present the development of a versatile protocol that allows for unprecedented efficiency in creation of synthetic protease-sensitive microniches for probing single stem cell fate in 3D.
Verbeke CS, Gordo S, Schubert DA, Lewin SA, Desai RM, Dobbins J, Wucherpfennig KW, Mooney DJ. Multicomponent Injectable Hydrogels for Antigen-Specific Tolerogenic Immune Modulation. Adv Healthc Mater. 2017;6 (6).Abstract
Biomaterial scaffolds that enrich and modulate immune cells in situ can form the basis for potent immunotherapies to elicit immunity or reëstablish tolerance. Here, the authors explore the potential of an injectable, porous hydrogel to induce a regulatory T cell (Treg) response by delivering a peptide antigen to dendritic cells in a noninflammatory context. Two methods are described for delivering the BDC peptide from pore-forming alginate gels in the nonobese diabetic mouse model of type 1 diabetes: encapsulation in poly(lactide-co-glycolide) (PLG) microparticles, or direct conjugation to the alginate polymer. While particle-based delivery leads to antigen-specific T cells responses in vivo, PLG particles alter the phenotype of the cells infiltrating the gels. Following gel-based peptide delivery, transient expansion of endogenous antigen-specific T cells is observed in the draining lymph nodes. Antigen-specific T cells accumulate in the gels, and, strikingly, ≈60% of the antigen-specific CD4(+) T cells in the gels are Tregs. Antigen-specific T cells are also enriched in the pancreatic islets, and administration of peptide-loaded gels does not accelerate diabetes. This work demonstrates that a noninflammatory biomaterial system can generate antigen-specific Tregs in vivo, which may enable the development of new therapies for the treatment of transplant rejection or autoimmune diseases.
Roche ET, Horvath MA, Wamala I, Alazmani A, Song S-E, Whyte W, Machaidze Z, Payne CJ, Weaver JC, Fishbein G, et al. Soft robotic sleeve supports heart function. Sci Transl Med. 2017;9 (373).Abstract
There is much interest in form-fitting, low-modulus, implantable devices or soft robots that can mimic or assist in complex biological functions such as the contraction of heart muscle. We present a soft robotic sleeve that is implanted around the heart and actively compresses and twists to act as a cardiac ventricular assist device. The sleeve does not contact blood, obviating the need for anticoagulation therapy or blood thinners, and reduces complications with current ventricular assist devices, such as clotting and infection. Our approach used a biologically inspired design to orient individual contracting elements or actuators in a layered helical and circumferential fashion, mimicking the orientation of the outer two muscle layers of the mammalian heart. The resulting implantable soft robot mimicked the form and function of the native heart, with a stiffness value of the same order of magnitude as that of the heart tissue. We demonstrated feasibility of this soft sleeve device for supporting heart function in a porcine model of acute heart failure. The soft robotic sleeve can be customized to patient-specific needs and may have the potential to act as a bridge to transplant for patients with heart failure.
Mao AS, Shin J-W, Utech S, Wang H, Uzun O, Li W, Cooper M, Hu Y, Zhang L, Weitz DA, et al. Deterministic encapsulation of single cells in thin tunable microgels for niche modelling and therapeutic delivery. Nat Mater. 2017;16 (2) :236-243.Abstract
Existing techniques to encapsulate cells into microscale hydrogels generally yield high polymer-to-cell ratios and lack control over the hydrogel's mechanical properties. Here, we report a microfluidic-based method for encapsulating single cells in an approximately six-micrometre layer of alginate that increases the proportion of cell-containing microgels by a factor of ten, with encapsulation efficiencies over 90%. We show that in vitro cell viability was maintained over a three-day period, that the microgels are mechanically tractable, and that, for microscale cell assemblages of encapsulated marrow stromal cells cultured in microwells, osteogenic differentiation of encapsulated cells depends on gel stiffness and cell density. We also show that intravenous injection of singly encapsulated marrow stromal cells into mice delays clearance kinetics and sustains donor-derived soluble factors in vivo. The encapsulation of single cells in tunable hydrogels should find use in a variety of tissue engineering and regenerative medicine applications.
2016
Li J, Mooney DJ. Designing hydrogels for controlled drug delivery. Nature Reviews Materials. 2016;1 :16071. Publisher's VersionAbstract
Hydrogel delivery systems can leverage therapeutically beneficial outcomes of drug delivery and have found clinical use. Hydrogels can provide spatial and temporal control over the release of various therapeutic agents, including small-molecule drugs, macromolecular drugs and cells. Owing to their tunable physical properties, controllable degradability and capability to protect labile drugs from degradation, hydrogels serve as a platform on which various physiochemical interactions with the encapsulated drugs occur to control drug release. In this Review, we cover multiscale mechanisms underlying the design of hydrogel drug delivery systems, focusing on physical and chemical properties of the hydrogel network and the hydrogel–drug interactions across the network, mesh and molecular (or atomistic) scales. We discuss how different mechanisms interact and can be integrated to exert fine control in time and space over drug presentation. We also collect experimental release data from the literature, review clinical translation to date of these systems and present quantitative comparisons between different systems to provide guidelines for the rational design of hydrogel delivery systems.
Shin J-W, Mooney DJ. Extracellular matrix stiffness causes systematic variations in proliferation and chemosensitivity in myeloid leukemias. Proc Natl Acad Sci U S A. 2016;113 (43) :12126-12131.Abstract
Extracellular matrix stiffness influences biological functions of some tumors. However, it remains unclear how cancer subtypes with different oncogenic mutations respond to matrix stiffness. In addition, the relevance of matrix stiffness to in vivo tumor growth kinetics and drug efficacy remains elusive. Here, we designed 3D hydrogels with physical parameters relevant to hematopoietic tissues and adapted them to a quantitative high-throughput screening format to facilitate mechanistic investigations into the role of matrix stiffness on myeloid leukemias. Matrix stiffness regulates proliferation of some acute myeloid leukemia types, including MLL-AF9(+) MOLM-14 cells, in a biphasic manner by autocrine regulation, whereas it decreases that of chronic myeloid leukemia BCR-ABL(+) K-562 cells. Although Arg-Gly-Asp (RGD) integrin ligand and matrix softening confer resistance to a number of drugs, cells become sensitive to drugs against protein kinase B (PKB or AKT) and rapidly accelerated fibrosarcoma (RAF) proteins regardless of matrix stiffness when MLL-AF9 and BCR-ABL are overexpressed in K-562 and MOLM-14 cells, respectively. By adapting the same hydrogels to a xenograft model of extramedullary leukemias, we confirm the pathological relevance of matrix stiffness in growth kinetics and drug sensitivity against standard chemotherapy in vivo. The results thus demonstrate the importance of incorporating 3D mechanical cues into screening for anticancer drugs.
Park J, Ku SK, Seo D, Hur K, Jeon H, Shvartsman D, Seok H-K, Mooney DJ, Lee K. Label-free bacterial detection using polydiacetylene liposomes. Chem Commun (Camb). 2016;52 (68) :10346-9.Abstract
Polydiacetylene (PDA) liposomes were prepared to selectively capture target released from bacteria. Specific interplay between released-surfactin and PDA resulted in a conformal change in the structure of PDA, highlighting the potential of indirect interactions between bacteria and PDA in the construction of new label-free bacterial sensors.
Zhang L, Cai L-H, Lienemann PS, Rossow T, Polenz I, Vallmajo-Martin Q, Ehrbar M, Na H, Mooney DJ, Weitz DA. One-Step Microfluidic Fabrication of Polyelectrolyte Microcapsules in Aqueous Conditions for Protein Release. Angew Chem Int Ed Engl. 2016;55 (43) :13470-13474.Abstract
We report a microfluidic approach for one-step fabrication of polyelectrolyte microcapsules in aqueous conditions. Using two immiscible aqueous polymer solutions, we generate transient water-in-water-in-water double emulsion droplets and use them as templates to fabricate polyelectrolyte microcapsules. The capsule shell is formed by the complexation of oppositely charged polyelectrolytes at the immiscible interface. We find that attractive electrostatic interactions can significantly prolong the release of charged molecules. Moreover, we demonstrate the application of these microcapsules in encapsulation and release of proteins without impairing their biological activities. Our platform should benefit a wide range of applications that require encapsulation and sustained release of molecules in aqueous environments.
Gu L, Mooney DJ. Biomaterials and emerging anticancer therapeutics: engineering the microenvironment. Nat Rev Cancer. 2016;16 (1) :56-66.Abstract
The microenvironment is increasingly recognized to have key roles in cancer, and biomaterials provide a means to engineer microenvironments both in vitro and in vivo to study and manipulate cancer. In vitro cancer models using 3D matrices recapitulate key elements of the tumour microenvironment and have revealed new aspects of cancer biology. Cancer vaccines based on some of the same biomaterials have, in parallel, allowed for the engineering of durable prophylactic and therapeutic anticancer activity in preclinical studies, and some of these vaccines have moved to clinical trials. The impact of biomaterials engineering on cancer treatment is expected to further increase in importance in the years to come.
Cezar CA, Roche ET, Vandenburgh HH, Duda GN, Walsh CJ, Mooney DJ. Biologic-free mechanically induced muscle regeneration. Proc Natl Acad Sci U S A. 2016;113 (6) :1534-9.Abstract
Severe skeletal muscle injuries are common and can lead to extensive fibrosis, scarring, and loss of function. Clinically, no therapeutic intervention exists that allows for a full functional restoration. As a result, both drug and cellular therapies are being widely investigated for treatment of muscle injury. Because muscle is known to respond to mechanical loading, we investigated instead whether a material system capable of massage-like compressions could promote regeneration. Magnetic actuation of biphasic ferrogel scaffolds implanted at the site of muscle injury resulted in uniform cyclic compressions that led to reduced fibrous capsule formation around the implant, as well as reduced fibrosis and inflammation in the injured muscle. In contrast, no significant effect of ferrogel actuation on muscle vascularization or perfusion was found. Strikingly, ferrogel-driven mechanical compressions led to enhanced muscle regeneration and a ∼threefold increase in maximum contractile force of the treated muscle at 2 wk compared with no-treatment controls. Although this study focuses on the repair of severely injured skeletal muscle, magnetically stimulated bioagent-free ferrogels may find broad utility in the field of regenerative medicine.
Koshy ST, Desai RM, Joly P, Li J, Bagrodia RK, Lewin SA, Joshi NS, Mooney DJ. Click-Crosslinked Injectable Gelatin Hydrogels. Adv Healthc Mater. 2016;5 (5) :541-7.Abstract
Injectable gelatin hydrogels formed with bioorthogonal click chemistry (ClickGel) are cell-responsive ECM mimics for in vitro and in vivo biomaterials applications. Gelatin polymers with pendant norbornene (GelN) or tetrazine (GelT) groups can quickly and spontaneously crosslink upon mixing, allowing for high viability of encapsulated cells, establishment of 3D elongated cell morphologies, and biodegradation when injected in vivo.
Li WA, Lu BY, Gu L, Choi Y, Kim J, Mooney DJ. The effect of surface modification of mesoporous silica micro-rod scaffold on immune cell activation and infiltration. Biomaterials. 2016;83 :249-56.Abstract
Biomaterial scaffold based vaccines show significant potential in generating potent antigen-specific immunity. However, the role of the scaffold surface chemistry in initiating and modulating the immune response is not well understood. In this study, a mesoporous silica micro-rod (MSR) scaffold was modified with PEG, PEG-RGD and PEG-RDG groups. PEG modification significantly enhanced BMDC activation marker up-regulation and IL-1β production in vitro, and innate immune cell infiltration in vivo. PEG-RGD MSRs and PEG-RDG MSRs displayed decreased inflammation compared to PEG MSRs, and the effect was not RGD specific. Finally, the Nlrp3 inflammasome was found to be necessary for MSR stimulated IL-1β production in vitro and played a key role in regulating immune cell infiltration in vivo. These findings suggest that simply modulating the surface chemistry of a scaffold can regulate its immune cell infiltration profile and have implications for the design and development of new material based vaccines.
Shin J-W, Mooney DJ. Improving Stem Cell Therapeutics with Mechanobiology. Cell Stem Cell. 2016;18 (1) :16-9.Abstract
In recent years, it has become clear that mechanical cues play an integral role in maintaining stem cell functions. Here we discuss how integrating physical approaches and engineering principles in stem cell biology, including culture systems, preclinical models, and functional assessment, may improve clinical application in regenerative medicine.
Ali OA, Lewin SA, Dranoff G, Mooney DJ. Vaccines Combined with Immune Checkpoint Antibodies Promote Cytotoxic T-cell Activity and Tumor Eradication. Cancer Immunol Res. 2016;4 (2) :95-100.Abstract
We demonstrate that a poly(lactide-co-glycolide) (PLG) cancer vaccine can be used in combination with immune checkpoint antibodies, anti-CTLA-4 or anti-PD-1, to enhance cytotoxic T-cell (CTL) activity and induce the regression of solid B16 tumors in mice. Combination therapy obviated the need for vaccine boosting and significantly skewed intratumoral reactions toward CTL activity, resulting in the regression of B16 tumors up to 50 mm(2) in size and 75% survival rates. These data suggest that combining material-based cancer vaccines with checkpoint antibodies has the potential to mediate tumor regression in humans.
Cheung AS, Koshy ST, Stafford AG, Bastings MMC, Mooney DJ. Adjuvant-Loaded Subcellular Vesicles Derived From Disrupted Cancer Cells for Cancer Vaccination. Small. 2016;12 (17) :2321-33.Abstract
Targeted subunit vaccines for cancer immunotherapy do not capture tumor antigenic complexity, and approaches employing tumor lysate are often limited by inefficient antigen uptake and presentation, and low immunogenicity. Here, whole cancer cells are processed to generate antigen-rich, membrane-enclosed subcellular particles, termed "reduced cancer cells", that reflect the diversity and breadth of the parent cancer cell antigen repertoire, and can be loaded with disparate adjuvant payloads. These vesicular particles enhance the uptake of the adjuvant payload, and potentiate the activation of primary dendritic cells in vitro. Similarly, reduced cancer cell-associated antigens are more efficiently presented by primary dendritic cells in vitro than their soluble counterparts or lysate control. In mice, vaccination using adjuvant-loaded reduced cancer cells facilitates the induction of antigen-specific cellular and humoral immune responses. Taken together, these observations demonstrate that adjuvant-loaded reduced cancer cells could be utilized in cancer vaccines as an alternative to lysate.

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