The mechanism of photocatalytic CO2 reduction by graphene-supported Cu2O probed by sacrificial electron donors

[EN] Cu2O nanoparticles of 5 nm average size have been adsorbed (1.74 wt% loading) on defective graphene (Cu2O/G) previously obtained by the pyrolysis of alginic acid sodium salt. The Cu2O crystal phase was determined by XRD. XPS shows that the external layers of the Cu2O nanoparticles are constituted mainly of Cu+ although a certain percentage of CuII+ was also present. Cu2O/G is a photocatalyst for the CO2 reduction to methane in the presence of sacrificial agents, and the rate of CH4 production depends on the oxidation potential of the electron donor. This relationship supports a mechanism involving photo-induced charge separation with the generation of electrons and holes. The highest CH4 formation rate upon UV-Vis irradiation of Cu2O/G with a 300 W Xe lamp was achieved for dimethylaniline reaching 326 mu mol CH4 per g per h. The spectral response of the Cu2O photocatalyst shows, however, that the response of the photocatalyst is mainly due to UV irradiation, indicating that light absorption at the low Cu2O loading on the Cu2O/G photocatalyst occurs mainly on the graphene component.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa SEV2016-0683, GRAPAS, and CTQ2015-69563-CO2-R1) and the Generalitat Valenciana (Prometeo 2015-083) is gratefully acknowledged. J. A. thanks the Universitat Politecnica de Valencia for a postdoctoral scholarship. D. M. also thanks the Spanish Ministry of Science for the PhD scholarship.Mateo-Mateo, D.; Asiri, AM.; Albero-Sancho, J.; García Gómez, H. (2018). The mechanism of photocatalytic CO2 reduction by graphene-supported Cu2O probed by sacrificial electron donors. Photochemical & Photobiological Sciences. 17(6):829-834. https://doi.org/10.1039/c7pp00442gS82983417

Combination of exosomes and near-infrared responsive gold nanoparticles: new selective and specific therapeutic vehicle

P602 Exosomes are extracellular vesicles (50 -150 nm of diameter) considered key elements for the intercellular communication. Although they are proposed to be ideal vehicles for the targeting of novel therapies, very little is known about the selectiveness and specificity of the transference processes involving exosomes released from different cells. PEGylated Hollow gold nanoparticles (PEG-HGNs) are near-infrared (NIR) responsive nanoparticles (NPs) which are able to generate localized heat by the use of NIR light leading to cell death when applying optical hyperthermia. In this study, we demonstrate the selectivity of in vitro exosomal transfer between certain cell types and how this phenomenon can be exploited to develop new specific vectors for advanced therapies. Firstly, PEG-HGNs were successfully incorporated in the exosome biogenesis pathway of placental stem cells (MSCs) and they were released as PEG-HGNs-loaded exosomes (PEGHGNs_ MSCs_EXOs). Exosomes were characterized by confocal microscopy, western blot, nanosight, zeta potential and electronic microscopy. Afterwards, time lapse microscopy and atomic emission spectroscopy demonstrated the selective transfer of the ..

All-carbon microporous graphitic photocatalyst-promoted reduction of CO2 to CO in the absence of metals or dopant elements

[EN] Microporous graphitic carbon (mp-C) derived from the pyrolysis of alpha-, beta-, and gamma-cyclodextrins exhibited photocatalytic activity in CO2-saturated acetonitrile-water upon irradiation with UV-Vis light and in the presence of triethanolamine, forming H-2 (19 mu mol h(-1)) and CO (23 mu mol h(-1)) accompanied by a lesser proportion of CH4 (4 mu mol h(-1)). The most efficient was the mp-C material derived from alpha-cyclodextrin (mp-C-alpha) and having a pore dimension of 0.68 nm. The process also occured, although to a much lesser extent, under simulated sunlight or with UV-Vis irradiation in the absence of a sacrificial agent, with H2O being the electron donor. The origin of the CO was proved by isotopic C-13 labelling experiments. Photocurrent measurements proved the occurrence of charge separation and the increase in photocurrent intensity in the presence of CO2. Transient absorption spectroscopy was used to detect the charge separate state decay in the microsecond time scale and proved that a fraction of the photogenerated electrons were able to react with CO2.Financial support by the Spanish Ministry of Science and Innovation (Severo Ochoa, PID-2021-12607OB-C21 and RTI2018-89237-CO2-1) and Generalitat Valenciana (Prometeo 2021/083) are gratefully acknowledged. A. G.-M. thanks the Spanish Ministry of Science and Innovation for a postgraduate scholarship.Garcia-Mulero, A.; Asiri, AM.; Albero-Sancho, J.; Primo Arnau, AM.; García Gómez, H. (2022). All-carbon microporous graphitic photocatalyst-promoted reduction of CO2 to CO in the absence of metals or dopant elements. Nanoscale. 14(32):11575-11582. https://doi.org/10.1039/d2nr02655d1157511582143

One-Pot Synthesis of nickel-modified carbon nitride layers toward efficient photoelectrochemical cells

[EN] A new method to significantly enhance the photoelectrochemical properties of phenyl-modified carbon nitride layers via the insertion of nickel ions into carbon nitride layers is reported. The nickel ions: are embedded within the carbon nitride layers by manipulating the interaction of Ni ions and molten organic molecules at elevated temperature prior to their condensation. A detailed analysis of the chemical and photophysical properties suggests that the nickel ions dissolve in the molten molecules, leading to the homogeneous distribution of nickel atoms within the carbon nitride layers. We found that the nickel atoms can alter the growth mechanism of carbon nitride layers, resulting in extended light absorption, charge transfer properties, and the total photoelectrochemical performance. For the most photoactive electrode, the Ni ions have an oxidation state of 2.8, as confirmed by soft X-ray absorption spectroscopy. Furthermore, important parameters such as absorption coefficient, exciton lifetime, and diffusion length were studied in depth, providing substantial progress in our understanding of the photoelectrochemical properties of carbon nitride films. This work opens new opportunities for the growth of carbon nitride layers and similar materials on different surfaces and provides important progress in our understanding of the photophysical and photoelectrochemical properties of carbon nitride layers toward their implantation in photoelectronic and other devices.We thank the use Katz Institute for Nanoscale Science & Technology Ben Gurion University for HR-TEM measurements. M.S. thanks Dr. Laurent Chabanne for fruitful discussion. K.M.L. is grateful for the support by the Helmholtz Association (VH-NG-1140).Zhang, W.; Albero-Sancho, J.; Xi, L.; Lange, KM.; García Gómez, H.; Wang, X.; Shalom, M. (2017). One-Pot Synthesis of nickel-modified carbon nitride layers toward efficient photoelectrochemical cells. ACS Applied Materials & Interfaces. 9(38):32667-32677. https://doi.org/10.1021/acsami.7b08022S326673267793

Isolation of exosomes from whole blood by a new microfluidic device: proof of concept application in the diagnosis and monitoring of pancreatic cancer

Background: Exosomes are endocytic-extracellular vesicles with a diameter around 100 nm that play an essential role on the communication between cells. In fact, they have been proposed as candidates for the diagnosis and the monitoring of different pathologies (such as Parkinson, Alzheimer, diabetes, cardiac damage, infection diseases or cancer). Results: In this study, magnetic nanoparticles (Fe3O4NPs) were successfully functionalized with an exosome-binding antibody (anti-CD9) to mediate the magnetic capture in a microdevice. This was carried out under flow in a 1.6 mm (outer diameter) microchannel whose wall was in contact with a set of NdFeB permanent magnets, giving a high magnetic field across the channel diameter that allowed exosome separation with a high yield. To show the usefulness of the method, the direct capture of exosomes from whole blood of patients with pancreatic cancer (PC) was performed, as a proof of concept. The captured exosomes were then subjected to analysis of CA19-9, a protein often used to monitor PC patients. Conclusions: Here, we describe a new microfluidic device and the procedure for the isolation of exosomes from whole blood, without any need of previous isolation steps, thereby facilitating translation to the clinic. The results show that, for the cases analyzed, the evaluation of CA19-9 in exosomes was highly sensitive, compared to serum samples

Polymer functionalized gold nanoparticles as non-viral gene delivery reagents.

Background: In this study we investigated the ability of PEG functionalized gold nanoparticles as non-viral vectors in the transfection of different cell lines, comparing them with commercial lipoplexes. Methods: Positively charged gold nanoparticles were synthesized using PEI as reducing and stabilizer agent and its cytotoxicity reduced by its functionalization with PEG. We bound the nanoparticles to three plasmids with different sizes (4-40 kpb). The vector internalization was evaluated by confocal and electronic microscopy. Its transfection efficacy was studied by fluorescence microscopy and flow cytometry. The application of the resulting vector in gene therapy was indirectly evaluated using ganciclovir in HeLa cells transfected to express the herpes virus thymidine kinase. Results: An appropriate ratio between the nitrogen from the PEI and the phosphorous from the phosphate groups of the DNA together with a reduced size and an elevated electrokinetic potential are responsible for an increased nanoparticle internalization and enhanced protein expression when carrying plasmids of up to 40kbp (plasmid size close to the limit of the DNA carrying capacity of viral vectors). Compared to a commercial transfection reagent, an equal or even higher expression of reporter genes (on HeLa and HEK 293T) and suicide effect on HeLa cells transfected with the herpes virus thymidine kinase gene were observed when using this novel nanoparticulated vector. Conclusions: Non-viral vectors based on gold nanoparticles covalently coupled with polyethylene glycol (PEG) and Polyethylenimine (PEI) can be used as efficient transfection reagents showing expression levels same or greater than the ones obtained with commercially available lipoplexes.pre-print3905 K

Efficiency of Antimicrobial Electrospun Thymol-Loaded Polycaprolactone Mats in Vivo

Due to the prevalence of antimicrobial resistant pathogens, natural products with long-term antimicrobial activities are considered as potential alternatives. In this work, polycaprolactone (PCL) electrospun fibers with mean diameters around 299 nm and loaded with 14.92 ± 1.31% w/w thymol (THY) were synthesized. The mats had appropriate elongation at break (74.4 ± 9.5%) and tensile strength (3.0 ± 0.5 MPa) to be potentially used as wound dressing materials. In vivo studies were performed using eight to ten week-old male SKH1 hairless mice. The infection progression was evaluated through a semiquantitative method and quantitative polymerase chain reaction. The analyses of post-mortem samples indicated that THY-loaded PCL fibers acted as inhibitors of Staphylococcus aureus ATCC 25923 strain growth being as efficient as chlorhexidine (CLXD). Histopathological and immunohistochemical studies showed that the PCL-THY-treated wounds were almost free of an inflammatory reaction. Therefore, wound dressings containing natural compounds can prevent infection and promote wound healing and prompt regeneration. Copyrigh

Drug-eluting wound dressings having sustained release of antimicrobial compounds

Wound healing is a complex and costly public health problem that should be timely addressed to achieve a rapid and adequate tissue repair avoiding or even eliminating potential pathogenic infection. Chronic infected non-healing wounds represent a serious concern for health care systems. Efficient wound dressings with tailored therapy having the best response and highest safety margin for the management of chronic non-healing wounds are still needed. The use of novel wound dressing materials has emerged as a promising tool to fulfil these requirements. In this work, asymmetric electrospun polycaprolactone (PCL)-based nanofibers (NFs) were decorated with electrosprayed poly(lactic-co-glycolic acid) microparticles (PLGA MPs) containing the natural antibacterial compound thymol (THY) in order to obtain drug eluting antimicrobial dressings having sustained release. The synthesized dressings successfully inhibited the in vitro growth of Staphylococcus aureus ATCC 25923, showing also at the same doses cytocompatibility on human dermal fibroblasts and keratinocyte cultures after treatment for 24 h, which was not observed when using free thymol. An in vivo murine excisional wound splinting model, followed by the experimental infection of the wounds with S. aureus and their treatment with the synthesized dressings, pointed to the reduction of the bacterial load in wounds after 7 days, though the total elimination of the infection was not reached. The findings indicated the relevance of the direct contact between the dressings and the bacteria, highlighting the need to tune their design considering the wound surface and the nature of the antimicrobial cargo contained

N-Doped graphene as a metal-free catalyst for glucose oxidation to succinic acid

[EN] N-Containing graphenes obtained either by simultaneous amination and reduction of graphene oxide or by pyrolysis of chitosan under an inert atmosphere have been found to act as catalysts for the selective wet oxidation of glucose to succinic acid. Selectivity values over 60% at complete glucose conversion have been achieved by performing the reaction at 160 degrees C and 18 atm O-2 pressure for 20 h. This activity has been attributed to graphenic-type N atoms on graphene. The active N-containing graphene catalysts were used four times without observing a decrease in conversion and selectivity of the process. A mechanism having tartaric and fumaric acids as key intermediates is proposed.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa, Grapas and CTQ2015-69153-CO2-R1) and Generalitat Valenciana (Prometeo 2013-014) is gratefully acknowledged. Prof. Simona M. Coman kindly acknowledges UEFISCDI for financial support (project PN-II-PT-PCCA-2013-4-1090, Nr. 44/2014). Cristina Bucur acknowledges Core Programme, Project PN-480103/2016.Rizescu, C.; Podolean, I.; Albero-Sancho, J.; Parvulescu, VI.; Coman, SM.; Bucur, C.; Puche Panadero, M.... (2017). N-Doped graphene as a metal-free catalyst for glucose oxidation to succinic acid. Green Chemistry. 19(8):1999-2005. https://doi.org/10.1039/C7GC00473GS19992005198Alonso, D. M., Wettstein, S. G., & Dumesic, J. A. (2012). Bimetallic catalysts for upgrading of biomass to fuels and chemicals. Chemical Society Reviews, 41(24), 8075. doi:10.1039/c2cs35188aCherubini, F. (2010). The biorefinery concept: Using biomass instead of oil for producing energy and chemicals. Energy Conversion and Management, 51(7), 1412-1421. doi:10.1016/j.enconman.2010.01.015Christensen, C. H., Rass-Hansen, J., Marsden, C. C., Taarning, E., & Egeblad, K. (2008). The Renewable Chemicals Industry. ChemSusChem, 1(4), 283-289. doi:10.1002/cssc.200700168Lange, J.-P. (2007). Lignocellulose conversion: an introduction to chemistry, process and economics. Biofuels, Bioproducts and Biorefining, 1(1), 39-48. doi:10.1002/bbb.7Corma, A., Iborra, S., & Velty, A. (2007). Chemical Routes for the Transformation of Biomass into Chemicals. Chemical Reviews, 107(6), 2411-2502. doi:10.1021/cr050989dCliment, M. J., Corma, A., & Iborra, S. (2011). Converting carbohydrates to bulk chemicals and fine chemicals over heterogeneous catalysts. Green Chemistry, 13(3), 520. doi:10.1039/c0gc00639dBjerre, A. B., Olesen, A. B., Fernqvist, T., Plöger, A., & Schmidt, A. S. (2000). Pretreatment of wheat straw using combined wet oxidation and alkaline hydrolysis resulting in convertible cellulose and hemicellulose. Biotechnology and Bioengineering, 49(5), 568-577. doi:10.1002/(sici)1097-0290(19960305)49:53.0.co;2-6Klinke, H. B., Ahring, B. K., Schmidt, A. S., & Thomsen, A. B. (2002). Characterization of degradation products from alkaline wet oxidation of wheat straw. Bioresource Technology, 82(1), 15-26. doi:10.1016/s0960-8524(01)00152-3Schmidt, A. S., & Thomsen, A. B. (1998). Optimization of wet oxidation pretreatment of wheat straw. Bioresource Technology, 64(2), 139-151. doi:10.1016/s0960-8524(97)00164-8Gogate, P. R., & Pandit, A. B. (2004). A review of imperative technologies for wastewater treatment I: oxidation technologies at ambient conditions. Advances in Environmental Research, 8(3-4), 501-551. doi:10.1016/s1093-0191(03)00032-7Mishra, V. S., Mahajani, V. V., & Joshi, J. B. (1995). Wet Air Oxidation. Industrial & Engineering Chemistry Research, 34(1), 2-48. doi:10.1021/ie00040a001Zakzeski, J., Bruijnincx, P. C. A., Jongerius, A. L., & Weckhuysen, B. M. (2010). The Catalytic Valorization of Lignin for the Production of Renewable Chemicals. Chemical Reviews, 110(6), 3552-3599. doi:10.1021/cr900354uPodolean, I., Rizescu, C., Bala, C., Rotariu, L., Parvulescu, V. I., Coman, S. M., & Garcia, H. (2016). Unprecedented Catalytic Wet Oxidation of Glucose to Succinic Acid Induced by the Addition ofn-Butylamine to a RuIIICatalyst. ChemSusChem, 9(17), 2307-2311. doi:10.1002/cssc.201600474Huang, C., Li, C., & Shi, G. (2012). Graphene based catalysts. Energy & Environmental Science, 5(10), 8848. doi:10.1039/c2ee22238hNavalon, S., Dhakshinamoorthy, A., Alvaro, M., & Garcia, H. (2014). Carbocatalysis by Graphene-Based Materials. Chemical Reviews, 114(12), 6179-6212. doi:10.1021/cr4007347Su, D. S., Perathoner, S., & Centi, G. (2013). Nanocarbons for the Development of Advanced Catalysts. Chemical Reviews, 113(8), 5782-5816. doi:10.1021/cr300367dDhakshinamoorthy, A., Primo, A., Concepcion, P., Alvaro, M., & Garcia, H. (2013). Doped Graphene as a Metal-Free Carbocatalyst for the Selective Aerobic Oxidation of Benzylic Hydrocarbons, Cyclooctane and Styrene. Chemistry - A European Journal, 19(23), 7547-7554. doi:10.1002/chem.201300653Huang, H., Huang, J., Liu, Y.-M., He, H.-Y., Cao, Y., & Fan, K.-N. (2012). Graphite oxide as an efficient and durable metal-free catalyst for aerobic oxidative coupling of amines to imines. Green Chemistry, 14(4), 930. doi:10.1039/c2gc16681jLi, X.-H., Chen, J.-S., Wang, X., Sun, J., & Antonietti, M. (2011). Metal-Free Activation of Dioxygen by Graphene/g-C3N4Nanocomposites: Functional Dyads for Selective Oxidation of Saturated Hydrocarbons. Journal of the American Chemical Society, 133(21), 8074-8077. doi:10.1021/ja200997aSun, H., Wang, Y., Liu, S., Ge, L., Wang, L., Zhu, Z., & Wang, S. (2013). Facile synthesis of nitrogen doped reduced graphene oxide as a superior metal-free catalyst for oxidation. Chemical Communications, 49(85), 9914. doi:10.1039/c3cc43401jYang, J.-H., Sun, G., Gao, Y., Zhao, H., Tang, P., Tan, J., … Ma, D. (2013). Direct catalytic oxidation of benzene to phenol over metal-free graphene-based catalyst. Energy & Environmental Science, 6(3), 793. doi:10.1039/c3ee23623dRocha, R. P., Gonçalves, A. G., Pastrana-Martínez, L. M., Bordoni, B. C., Soares, O. S. G. P., Órfão, J. J. M., … Pereira, M. F. R. (2015). Nitrogen-doped graphene-based materials for advanced oxidation processes. Catalysis Today, 249, 192-198. doi:10.1016/j.cattod.2014.10.046Wang, Y., Xie, Y., Sun, H., Xiao, J., Cao, H., & Wang, S. (2016). Efficient Catalytic Ozonation over Reduced Graphene Oxide for p-Hydroxylbenzoic Acid (PHBA) Destruction: Active Site and Mechanism. ACS Applied Materials & Interfaces, 8(15), 9710-9720. doi:10.1021/acsami.6b01175Duan, X., Su, C., Zhou, L., Sun, H., Suvorova, A., Odedairo, T., … Wang, S. (2016). Surface controlled generation of reactive radicals from persulfate by carbocatalysis on nanodiamonds. Applied Catalysis B: Environmental, 194, 7-15. doi:10.1016/j.apcatb.2016.04.043Kang, J., Duan, X., Zhou, L., Sun, H., Tadé, M. O., & Wang, S. (2016). Carbocatalytic activation of persulfate for removal of antibiotics in water solutions. Chemical Engineering Journal, 288, 399-405. doi:10.1016/j.cej.2015.12.040Sun, H., Kwan, C., Suvorova, A., Ang, H. M., Tadé, M. O., & Wang, S. (2014). Catalytic oxidation of organic pollutants on pristine and surface nitrogen-modified carbon nanotubes with sulfate radicals. Applied Catalysis B: Environmental, 154-155, 134-141. doi:10.1016/j.apcatb.2014.02.012Wang, X., Qin, Y., Zhu, L., & Tang, H. (2015). Nitrogen-Doped Reduced Graphene Oxide as a Bifunctional Material for Removing Bisphenols: Synergistic Effect between Adsorption and Catalysis. Environmental Science & Technology, 49(11), 6855-6864. doi:10.1021/acs.est.5b01059Lai, L., Potts, J. R., Zhan, D., Wang, L., Poh, C. K., Tang, C., … Ruoff, R. S. (2012). Exploration of the active center structure of nitrogen-doped graphene-based catalysts for oxygen reduction reaction. Energy & Environmental Science, 5(7), 7936. doi:10.1039/c2ee21802jLi, X., Wang, H., Robinson, J. T., Sanchez, H., Diankov, G., & Dai, H. (2009). Simultaneous Nitrogen Doping and Reduction of Graphene Oxide. Journal of the American Chemical Society, 131(43), 15939-15944. doi:10.1021/ja907098fLong, D., Li, W., Ling, L., Miyawaki, J., Mochida, I., & Yoon, S.-H. (2010). Preparation of Nitrogen-Doped Graphene Sheets by a Combined Chemical and Hydrothermal Reduction of Graphene Oxide. Langmuir, 26(20), 16096-16102. doi:10.1021/la102425aLavorato, C., Primo, A., Molinari, R., & Garcia, H. (2013). N-Doped Graphene Derived from Biomass as a Visible-Light Photocatalyst for Hydrogen Generation from Water/Methanol Mixtures. Chemistry - A European Journal, 20(1), 187-194. doi:10.1002/chem.201303689Primo, A., Atienzar, P., Sanchez, E., Delgado, J. M., & García, H. (2012). From biomass wastes to large-area, high-quality, N-doped graphene: catalyst-free carbonization of chitosan coatings on arbitrary substrates. Chemical Communications, 48(74), 9254. doi:10.1039/c2cc34978gPrimo, A., Sánchez, E., Delgado, J. M., & García, H. (2014). High-yield production of N-doped graphitic platelets by aqueous exfoliation of pyrolyzed chitosan. Carbon, 68, 777-783. doi:10.1016/j.carbon.2013.11.068Chan, L. H., Hong, K. H., Xiao, D. Q., Lin, T. C., Lai, S. H., Hsieh, W. J., & Shih, H. C. (2004). Resolution of the binding configuration in nitrogen-doped carbon nanotubes. Physical Review B, 70(12). doi:10.1103/physrevb.70.125408Guo, B., Liu, Q., Chen, E., Zhu, H., Fang, L., & Gong, J. R. (2010). Controllable N-Doping of Graphene. Nano Letters, 10(12), 4975-4980. doi:10.1021/nl103079jSun, L., Wang, L., Tian, C., Tan, T., Xie, Y., Shi, K., … Fu, H. (2012). Nitrogen-doped graphene with high nitrogen level via a one-step hydrothermal reaction of graphene oxide with urea for superior capacitive energy storage. RSC Advances, 2(10), 4498. doi:10.1039/c2ra01367cAsedegbega-Nieto, E., Perez-Cadenas, M., Morales, M. V., Bachiller-Baeza, B., Gallegos-Suarez, E., Rodriguez-Ramos, I., & Guerrero-Ruiz, A. (2014). High nitrogen doped graphenes and their applicability as basic catalysts. Diamond and Related Materials, 44, 26-32. doi:10.1016/j.diamond.2014.01.019Jiang, H., Yu, X., Nie, R., Lu, X., Zhou, D., & Xia, Q. (2016). Selective hydrogenation of aromatic carboxylic acids over basic N-doped mesoporous carbon supported palladium catalysts. Applied Catalysis A: General, 520, 73-81. doi:10.1016/j.apcata.2016.04.009Primo, A., Parvulescu, V., & Garcia, H. (2016). Graphenes as Metal-Free Catalysts with Engineered Active Sites. The Journal of Physical Chemistry Letters, 8(1), 264-278. doi:10.1021/acs.jpclett.6b0199

Cancer-derived exosomes loaded with ultrathin palladium nanosheets for targeted bioorthogonal catalysis

The transformational impact of bioorthogonal chemistries has inspired new strategies for the in vivo synthesis of bioactive agents through non-natural means. Among these, Pd catalysts have played a prominent role in the growing subfield of bioorthogonal catalysis by producing xenobiotics and uncaging biomolecules in living systems. However, delivering catalysts selectively to specific cell types still lags behind catalyst development. Here, we have developed a bioartificial device comprising cancer-derived exosomes that are loaded with Pd catalysts by a method that enables the controlled assembly of Pd nanosheets directly inside the vesicles. This hybrid system mediates Pd-triggered dealkylation reactions in vitro and inside cells, and displays preferential tropism for their progenitor cells. The use of Trojan exosomes to deliver abiotic catalysts into designated cancer cells creates the opportunity for a new targeted therapy modality; that is, exosome-directed catalyst prodrug therapy, whose first steps are presented herein with the cell-specific release of the anticancer drug panobinostat