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1.
J Colloid Interface Sci ; 581(Pt A): 135-147, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32771725

RESUMO

HYPOTHESIS: Molecular architecture and composition of amphiphilic bottlebrush copolymers will dictate the dominant interfacial relaxation modes and the corresponding dilatational rheology for adsorbed layers at oil/water interfaces in a way that will correlate with the emulsifying efficiency of different bottlebrush copolymers. EXPERIMENTS: Amphiphilic, xylene-soluble poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PBA) heterografted bottlebrush copolymers with controlled differences in backbone length, hydrophilicity and arm length were synthesized by atom transfer radical polymerization. Dilatational rheology of adsorbed layers at the xylene/water interface was probed via pendant drop tensiometry by measuring the interfacial stress response to either large-amplitude strain cycling or small-amplitude strain oscillation. The rheological response was recorded as a function of interfacial pressure for adsorbed layers under different compression states. Emulsifying efficiency was determined as the lowest copolymer concentration that yielded water-in-xylene emulsions with at least one-month stability against coalescence. FINDINGS: The more hydrophilic copolymers with longer PEO arms exhibited non-hysteretic stress-strain response curves in large-amplitude strain cycling and a tendency for the modulus to increase with increasing interfacial pressure. These were more efficient emulsifiers than less hydrophilic copolymers that exhibited hysteretic interfacial rheology. Mere existence of significant moduli did not correlate with high emulsifying efficiency, while an increase in modulus with increasing interfacial pressure did so.

2.
Adv Mater ; : e2004732, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-33251706

RESUMO

Photothermal energy conversion is of fundamental importance to applications ranging from drug delivery to microfluidics and from ablation to fabrication. It typically originates from absorptive processes in materials that-when coupled with non-radiative dissipative processes-allow the conversion of radiative energy into heat. Microstructure design provides versatile strategies for controlling light-matter interactions. In particular, the deliberate engineering of the band structure in photonic materials is known to be an effective approach to amplify absorption in materials. However, photonic amplification is generally tied to high optical contrast materials which limit the applicability of the concept to metamaterials such as microfabricated metal-air hybrids. This contribution describes the first observation of pronounced amplification of absorption in low contrast opals formed by the self-assembly of polymer-tethered particles. The dependence of the amplification factor on the length scale and degree of order of materials as well as the angle of incidence reveal that it is related to the slow photon effect. A remarkable amplification factor of 16 is shown to facilitate the rapid "melting" of opal films even in the absence of "visible" absorption. The results point to novel opportunities for tailoring light-matter interactions in hybrid materials that can benefit the manipulation and fabrication of functional materials.

3.
Artigo em Inglês | MEDLINE | ID: mdl-33040537

RESUMO

The vulcanization of rubber is a chemical process to improve the mechanical properties by cross-linking unsaturated polymer chains. Zinc oxide (ZnO) acts as an activator, boosting the rubbers' sulfur vulcanization. Maintaining the level of ZnO content in the rubber compounds as low as possible is desirable, not only for economic reasons but also to reduce the environmental footprint of the process. In this contribution, octylamine (OA) capped ZnO nanoparticles (5 nm diameter), prepared through a thermal decomposition method, were demonstrated to be efficient activators for the sulfur vulcanization of natural rubber, enabling the reduction of the required amount of ZnO as compared to commercial systems. The effect of different ZnO activators (OA capped ZnO/commercial indirect process ZnO) on the curing characteristics, cross-linking densities, and mechanical performance, as well as the thermal behavior of rubber compounds, were investigated. Compared to the commercial indirect process ZnO, OA capped ZnO nanoparticles not only effectively enhanced the curing efficiency of natural rubber but also improved the mechanical performance of the composites after vulcanization. This was interpreted as, by applying the OA capped ZnO nanoparticles, the ZnO levels in rubber compounding were significantly reduced under the industrial vulcanization condition (151 °C, 30 min).

4.
J Am Chem Soc ; 142(35): 14843-14847, 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32790294

RESUMO

In this study, we report lubrication properties of physisorbed zwitterionic bottlebrush polymers in the presence of multivalent ions using the surface force apparatus. Unlike polyelectrolyte brushes, the lubrication properties of which diminish drastically in the presence of multivalent ions at concentrations as low as 0.1 mM, zwitterionic bottlebrush polymers exhibit friction coefficients as low as ∼10-3 at such concentrations of multivalent ions up to intermediate normal loads. This lubrication ability persists until surface wear occurs at high normal loads. The surface wear is demonstrated to be triggered by the multivalent ions bridging the polymer chains and dehydrating the zwitterionic moieties. Finally, the analysis of the polymer film stability suggests that the partial desorption of polymers in the presence of the ions does not affect the lubrication performance. Therefore, even in the physisorbed state, zwitterionic brushes perform significantly better than covalently grafted polyelectrolyte brushes in the presence of multivalent ions.

5.
Chem Rev ; 120(17): 9363-9419, 2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32786418

RESUMO

Heteroatom-doped porous carbon materials (HPCMs) have found extensive applications in adsorption/separation, organic catalysis, sensing, and energy conversion/storage. The judicious choice of carbon precursors is crucial for the manufacture of HPCMs with specific usages and maximization of their functions. In this regard, polymers as precursors have demonstrated great promise because of their versatile molecular and nanoscale structures, modulatable chemical composition, and rich processing techniques to generate textures that, in combination with proper solid-state chemistry, can be maintained throughout carbonization. This Review comprehensively surveys the progress in polymer-derived functional HPCMs in terms of how to produce and control their porosities, heteroatom doping effects, and morphologies and their related use. First, we summarize and discuss synthetic approaches, including hard and soft templating methods as well as direct synthesis strategies employing polymers to control the pores and/or heteroatoms in HPCMs. Second, we summarize the heteroatom doping effects on the thermal stability, electronic and optical properties, and surface chemistry of HPCMs. Specifically, the heteroatom doping effect, which involves both single-type heteroatom doping and codoping of two or more types of heteroatoms into the carbon network, is discussed. Considering the significance of the morphologies of HPCMs in their application spectrum, potential choices of suitable polymeric precursors and strategies to precisely regulate the morphologies of HPCMs are presented. Finally, we provide our perspective on how to predefine the structures of HPCMs by using polymers to realize their potential applications in the current fields of energy generation/conversion and environmental remediation. We believe that these analyses and deductions are valuable for a systematic understanding of polymer-derived carbon materials and will serve as a source of inspiration for the design of future HPCMs.

6.
Biomacromolecules ; 21(9): 3867-3877, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32786529

RESUMO

Organophosphorus nerve agents (OPNAs), used in chemical warfare, irreversibly inhibit essential cholinesterases (ChEs) in the cholinergic neurotransmission system. Several potent nucleophilic oximes have been approved for the treatment of acute poisoning by OPNAs, but they are rapidly cleared from blood circulation. Butyrylcholinesterase (BChE) stoichiometrically binds nerve agents, but because the molecular weight of a nerve agent is about 500-fold less than the enzyme, the bioscavenger has had limited utility. We synthesized BChE-polymer-oxime conjugates using atom transfer radical polymerization (ATRP) and azide-alkyne "click" chemistry. The activity of the BChE-polymer-oxime conjugates was dependent on the degree of oxime loading within the copolymer side chains. The covalent modification of oxime-containing copolymers prolonged the activity of BChE in the presence of the VX- and cyclosarin-fluorogenic analogues EMP-MeCyC and CMP-MeCyC, respectively. After complete inactivation by VX and cyclosarin fluorogenic analogues, the conjugates demonstrated efficient self-reactivation of up to 80% within 3-6 h. Repeated inhibition and high-level self-reactivation assays revealed that the BChE-polymer-oxime conjugates were excellent reactivators of OPNA-inhibited BChE. Recurring self-reactivation of BChE-polymer-oxime conjugates following repeated BChE inhibition by fluorogenic OPNAs (Flu-OPNAs) opens the door to developing the next generation of nerve agent "catalytic" bioscavengers.

7.
ACS Nano ; 14(9): 10954-10965, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32628009

RESUMO

Climate change is increasing the severity and length of heat waves. Heat stress limits crop productivity and can make plants more sensitive to other biotic and abiotic stresses. New methods for managing heat stress are needed. Herein, we have developed ∼30 nm diameter poly(acrylic acid)-block-poly(N-isopropylacrylamide) (PAA-b-PNIPAm) star polymers with varying block ratios for temperature-programmed release of a model antimicrobial agent (crystal violet, CV) at plant-relevant pH. Hyperspectral-Enhanced Dark field Microscopy was used to investigate star polymer-leaf interactions and route of entrance. The majority of loaded star polymers entered plant leaves through cuticular and epidermis penetration when applied with the adjuvant Silwet L-77. Up to 43 wt % of star polymers (20 µL at 200 mg L-1 polymer concentration) applied onto tomato (Solanum lycopersicum) leaves translocated to other plant compartments (younger and older shoots, stem, and root) over 3 days. Without Silwet L-77, the star polymers penetrated the cuticle, but mainly accumulated at the epidermis cell layer. The degree of the star polymer temperature responsiveness for CV release in vitro in the range of 20 to 40 °C depends on pH and the ratio of the PAA to PNIPAm blocks. Temperature-responsive release of CV was also observed in vivo in tomato leaves. These results underline the potential for PAA-b-PNIPAm star polymers to provide efficient and temperature-programmed delivery of cationic agrochemicals into plants for protection against heat stress.

8.
ACS Nano ; 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32649179

RESUMO

Liquid metal (LM) micro/nano droplets have promising applications in various fields such as flexible electronics, catalysis, and soft composites as well as biomedicines. However, the preparation of highly stable LM nanodroplets suspension based on eutectic gallium/indium (EGaIn) alloys is still challenging. Herein, we report a general and robust strategy to fabricate EGaIn nanodroplets stabilized by polymer brushes (polymer brushes/EGaIn nanodroplets) via in situ attachment of well-defined diblock copolymers with short poly(acrylic acid) (PAA) anchoring segments. Under ultrasonication, the anchoring PAA block is in situ attached onto the gallium oxide "skin" layer of EGaIn nanodroplets to form polymer brushes. The attachable diblock copolymer surfactants allow for highly efficient formation of EGaIn nanodroplets in high yield and with narrow size distribution. The polymer brushes/EGaIn nanodroplets contain very low fractions of attached polymer (<1 wt %) and exhibit high colloidal stability (>30 days) and good redispersibility. Precise control of polymer architecture by atom-transfer radical polymerization was employed to prepare various block copolymers for suspensions in a variety of solvents.

9.
Macromol Rapid Commun ; 41(14): e2000264, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32529731

RESUMO

Halogen exchange in atom transfer radical polymerization (ATRP) is an efficient way to chain-extend from a less active macroinitiator (MI) to a more active monomer. This has been previously achieved by using CuCl/L in the equimolar amount to Pn -Br MI in the chain extension step. However, this approach cannot be effectively applied in systems based on regeneration of activators (ARGET ATRP), since they operate with ppm amounts of catalysts. Herein, a catalytic halogen exchange procedure is reported using a catalytic amount of Cu in miniemulsion ARGET ATRP to chain-extend from a less active poly(n-butyl acrylate) (PBA) MI to a more active methyl methacrylate (MMA) monomer. Influence of different reagents on the initiation efficiency and dispersity is studied. Addition of 0.1 m NaCl or tetraethylammonium chloride to ATRP of MMA initiated by methyl 2-bromopropionate leads to high initiation efficiency and polymers with low dispersity. The optimized conditions are then employed in chain extension of PBA MI with MMA to prepare diblock and triblock copolymers.

10.
Artigo em Inglês | MEDLINE | ID: mdl-32416006

RESUMO

A facile and efficient two-step synthesis of p-substituted tris(2-pyridylmethyl)amine (TPMA) ligands to form Cu complexes with the highest activity to date in atom transfer radical polymerization (ATRP) is presented. In the divergent synthesis, p-Cl substituents in tris(4-chloro-2-pyridylmethyl)amine (TPMA3Cl ) were replaced in one step and high yield by electron-donating cyclic amines (pyrrolidine (TPMAPYR ), piperidine (TPMAPIP ), and morpholine (TPMAMOR )) by nucleophilic aromatic substitution. The [CuII (TPMANR2 )Br]+ complexes exhibited larger energy gaps between frontier molecular orbitals and >0.2 V more negative reduction potentials than [CuII (TPMA)Br]+ , indicating >3 orders of magnitude higher ATRP activity. [CuI (TPMAPYR )]+ exhibited the highest reported activity for Br-capped acrylate chain ends in DMF, and moderate activity toward C-F bonds at room temperature. ATRP of n-butyl acrylate using only 10-25 part per million loadings of [CuII (TPMANR2 )Br]+ exhibited excellent control.

11.
Molecules ; 25(7)2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32260141

RESUMO

Catalysts are essential for mediating a controlled polymerization in atom transfer radical polymerization (ATRP). Copper-based catalysts are widely explored in ATRP and are highly efficient, leading to well-controlled polymerization of a variety of functional monomers. In addition to copper, iron-based complexes offer new opportunities in ATRP catalysis to develop environmentally friendly, less toxic, inexpensive, and abundant catalytic systems. Despite the high efficiency of iron catalysts in controlling polymerization of various monomers including methacrylates and styrene, ATRP of acrylate-based monomers by iron catalysts still remains a challenge. In this paper, we review the fundamentals and recent advances of iron-catalyzed ATRP focusing on development of ligands, catalyst design, and techniques used for iron catalysis in ATRP.

12.
J Am Chem Soc ; 142(6): 3158-3164, 2020 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-31967475

RESUMO

The use of zerovalent iron (Fe0)-coated plates, which act both as a source of catalyst and as a reducing agent during surface-initiated atom transfer radical polymerization (SI-ATRP), enables the controlled growth of a wide range of polymer brushes under ambient conditions utilizing either organic or aqueous reaction media. Thanks to its cytocompatibility, Fe0 SI-ATRP can be applied within cell cultures, providing a tool that can broadly and dynamically modify the substrate's affinity toward cells, without influencing their viability. Upon systematically assessing the application of Fe-based catalytic systems in the controlled grafting of polymers, Fe0 SI-ATRP emerges as an extremely versatile technique that could be applied to tune the physicochemical properties of a cell's microenvironments on biomaterials or within tissue engineering constructs.

13.
Macromol Rapid Commun ; 41(1): e1900424, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31631429

RESUMO

Small molecule biomimetics inspired by the active site of the [FeFe]-hydrogenase enzymes have shown promising electrocatalytic activity for hydrogen (H2 ) generation. However, most of the active-site mimics based on [2Fe-2S] clusters are not water-soluble which limits the use of these electrocatalysts to organic media. Polymer-supported [2Fe-2S] systems, in particular, single-site metallopolymer catalysts, have shown drastic improvements for electrocatalytic H2 generation in aqueous milieu. [2Fe-2S] complexes functionalized within well-defined macromolecular supports via covalent bonding have demonstrated water solubility, enhanced site-isolation, and improved chemical stability during catalysis. In this report, the synthesis of a new propanedithiolate (pdt)-[2Fe-2S] complex bearing a single α-bromoester moiety for use in atom transfer radical polymerization (ATRP) is demonstrated as a novel metalloinitiator to prepare water-soluble poly(2-dimethylaminoethyl methacrylate) grafted (PDMAEMA-g-[2Fe-2S]) metallopolymers. Using this approach, metallopolymers with controllable molecular weights (Mn = 5-40 kg mol-1 ) and low dispersity (D, Mw /Mn = 1.09-1.36) are prepared, which allows for the first time observation of the effect of the metallopolymers' chain length on the electrocatalytic activity. The ability to control the composition and molecular weight of these metallopolymers enables macromolecular engineering via ATRP of these materials to determine optimal structural features of metallopolymer catalysts for H2 production.

14.
Biomacromolecules ; 20(12): 4272-4298, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31738532

RESUMO

Proteins, nucleic acids, lipid vesicles, and carbohydrates are the major classes of biomacromolecules that function to sustain life. Biology also uses post-translation modification to increase the diversity and functionality of these materials, which has inspired attaching various other types of polymers to biomacromolecules. These polymers can be naturally (carbohydrates and biomimetic polymers) or synthetically derived and have unique properties with tunable architectures. Polymers are either grafted-to or grown-from the biomacromolecule's surface, and characteristics including polymer molar mass, grafting density, and degree of branching can be controlled by changing reaction stoichiometries. The resultant conjugated products display a chimerism of properties such as polymer-induced enhancement in stability with maintained bioactivity, and while polymers are most often conjugated to proteins, they are starting to be attached to nucleic acids and lipid membranes (cells) as well. The fundamental studies with protein-polymer conjugates have improved our synthetic approaches, characterization techniques, and understanding of structure-function relationships that will lay the groundwork for creating new conjugated biomacromolecular products which could lead to breakthroughs in genetic and tissue engineering.

15.
Molecules ; 24(21)2019 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-31684005

RESUMO

Copper is the most common metal catalyst used in atom transfer radical polymerization (ATRP), but iron is an excellent alternative due to its natural abundance and low toxicity compared to copper. In this work, two new iron-porphyrin-based catalysts inspired by naturally occurring proteins, such as horseradish peroxidase, hemoglobin, and cytochrome P450, were synthesized and tested for ATRP. Natural protein structures were mimicked by attaching imidazole or thioether groups to the porphyrin, leading to increased rates of polymerization, as well as providing polymers with low dispersity, even in the presence of ppm amounts of catalysts.


Assuntos
Biomimética , Ferro/química , Polimerização , Porfirinas/química , Catálise , Cobre/química , Sistema Enzimático do Citocromo P-450/química , Hemoglobinas/química , Peroxidase do Rábano Silvestre/química , Imidazóis/química , Estrutura Molecular , Oxirredução , Polímeros/química , Sulfetos/química
16.
Nat Commun ; 10(1): 4718, 2019 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-31624254

RESUMO

Almost all commercial proteins are purified using ammonium sulfate precipitation. Protein-polymer conjugates are synthesized from pure starting materials, and the struggle to separate conjugates from polymer, native protein, and from isomers has vexed scientists for decades. We have discovered that covalent polymer attachment has a transformational effect on protein solubility in salt solutions. Here, protein-polymer conjugates with a variety of polymers, grafting densities, and polymer lengths are generated using atom transfer radical polymerization. Charged polymers increase conjugate solubility in ammonium sulfate and completely prevent precipitation even at 100% saturation. Atomistic molecular dynamic simulations show the impact is driven by an anti-polyelectrolyte effect from zwitterionic polymers. Uncharged polymers exhibit polymer length-dependent decreased solubility. The differences in salting-out are then used to simply purify mixtures of conjugates and native proteins into single species. Increasing protein solubility in salt solutions through polymer conjugation could lead to many new applications of protein-polymer conjugates.


Assuntos
Polimerização , Polímeros/química , Proteínas/química , Solubilidade , Eletroforese em Gel de Poliacrilamida , Polímeros/metabolismo , Conformação Proteica , Proteínas/metabolismo , Sais , Soluções/química
17.
ACS Appl Mater Interfaces ; 11(42): 38531-38536, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31599570

RESUMO

Titanium (Ti) and its alloys are used in orthopedic and dental implants due to their excellent physical properties and biocompatibility. Although Ti exhibits superior osteoconductive properties compared to those of polymer-based implants, improved bone-on growth properties are required for enhanced surgical outcomes and improved recovery surgical interventions. Herein, we demonstrate a novel surface modification strategy to enhance the osteoconductivity of Ti surfaces through the grafting-from procedure of a reactive copolymer via surface-initiated atom transfer radical polymerization (SI-ATRP). Then, postpolymerization conjugation of the P15 peptide, an osteoblast binding motif, was successfully carried out. Subsequent in vitro studies revealed that the surface modification promoted osteoblast attachment on the Ti discs at 6 and 24 h. Moreover, mineral matrix deposition by osteoblasts was greater for the surface-modified Ti than for plain Ti and P15 randomly absorbed onto the Ti surface. These results suggest that the strategy for postpolymerization incorporation of P15 onto a Ti surface with a polymer interface may provide improved osseointegration outcomes, leading to enhanced quality of life for patients.


Assuntos
Ligas/farmacologia , Colágeno/química , Osseointegração/efeitos dos fármacos , Fragmentos de Peptídeos/química , Titânio/química , Ligas/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Implantes Dentários , Camundongos , Osteoblastos/citologia , Osteoblastos/metabolismo
18.
ACS Omega ; 4(14): 16247-16255, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31592088

RESUMO

Developing visible-light-regulated controlled/living radical polymerization techniques for the synthesis of polymers with a predictable molecular weight, spatial and temporal control, and well-defined end-group functionality is being pursued by the macromolecular community worldwide. In this study, a new metal-free photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization system was developed for controlled macromolecular synthesis in both heterogeneous and homogeneous systems by structural engineering of graphitic carbon nitrides (g-C3N4) to improve the textural, optical, and electronic properties. A heteroatom-mediated synthesis enabled the preparation of g-C3N4 with improved structural properties and increased absorption in the visible light region. Enhanced PET-RAFT polymerization of vinyl monomers with low dispersity (D < 1.2), temporal control, and high chain-end fidelity was achieved under mild blue light irradiation (λmax = 465 nm, 3 mW/cm2). Moreover, we demonstrate, for the first time, that the g-C3N4-catalyzed RAFT polymerization could be realized in a homogeneous system after structural evolution of bulk g-C3N4 into soluble nanosheets with enhanced photocatalytic efficiency up to high monomer conversion. This study provides new insights into the structure-performance relationship of g-C3N4 for photoregulated PET-RAFT polymerization under visible light. Moreover, the development of a homogeneous g-C3N4-catalyzed photosynthesis system should broaden the application scope of these fascinating photocatalysts while benefiting synthetic upscaling by continuous flow and/or microfluidic reactors.

19.
Langmuir ; 35(48): 15535-15542, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31478669

RESUMO

Challenges associated with nonspecific adsorption of proteins on sensor surfaces have steered the development of novel antifouling materials and strategies. Inspired by human synovial fluid composition and structure, we designed synergistic antifouling coatings with mixtures of hyaluronic acid (HA) and a zwitterionic bottlebrush polymer (BB). Using a fast and convenient online surface modification method, the polymers were immobilized on the Au surface, significantly increasing its hydrophilicity. Using surface plasmon resonance (SPR), a 10:1 ratio of HA to BB was found optimal to provide the best antifouling performance. Bovine serum albumin (BSA) adsorption on HA-BB coated surfaces was 0.2 ng/cm2, which was 60 times lower than BB or HA alone and 25 times lower than the commonly accepted ultralow adsorption limit (<5 ng/cm2), demonstrating the synergistic effect of HA and BB against nonspecific protein adsorption. This was found to be independent of BSA concentration up to physiological concentrations. Furthermore, the antifouling performance of HA-BB coated surfaces was tested against milk and serum, showing almost 92% lower protein adsorption than that on bare surfaces, suggesting the potential efficacy of this antifouling coating in real life settings.

20.
ACS Nano ; 13(9): 10555-10565, 2019 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-31436946

RESUMO

Exosomes show potential as ideal vehicles for drug delivery because of their natural role in transferring biological cargo between cells. However, current methods to engineer exosomes without negatively impacting their function remain challenging. Manipulating exosome-secreting cells is complex and time-consuming, while direct functionalization of exosome surface proteins suffers from low specificity and low efficiency. We demonstrate a rapid, versatile, and scalable method with oligonucleotide tethers to enable diverse surface functionalization on both human and murine exosomes. These exosome surface modifiers, which range from reactive functional groups and small molecules to aptamers and large proteins, can readily and efficiently enhance native exosome properties. We show that cellular uptake of exosomes can be specifically altered with a tethered AS1411 aptamer, and targeting specificity can be altered with a tethered protein. We functionalize exosomes with an immunomodulatory protein, FasL, and demonstrate their biological activity both in vitro and in vivo. FasL-functionalized exosomes, when bioprinted on a collagen matrix, allows spatial induction of apoptosis in tumor cells and, when injected in mice, suppresses proliferation of alloreactive T cells. This oligonucleotide tethering strategy is independent of the exosome source and further circumvents the need to genetically modify exosome-secreting cells.

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