A microfluidic platform for combinatorial synthesis and optimization of targeted polymeric nanoparticles for cancer therapy

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, February 2013."November 2012." Cataloged from PDF version of thesis.Includes bibliographical references.The use of nanotechnology to engineer drug delivery vehicles comprised of controlled release polymers with targeting molecules has the potential to revolutionize cancer therapy, among other diseases. Although a myriad of nanotherapeutics have been developed at the bench side, many of them stay at the research stage due to their complexity and difficulty in their optimization. A key challenge for optimization of nanoparticles (NPs) for drug delivery is the ability to systematically and combinatorially create and screen libraries of NPs with distinct physicochemical properties, from which promising formulations can be moved forward to preclinical and clinical studies. In this work, the development of a controlled method to synthesize libraries of NPs with distinct properties is described. The procedure uses a microfluidic platform that rapidly mixes reagents and provides homogeneous reaction environments, resulting in the reproducible, single-step synthesis of NPs with well-defined properties and narrow size distributions. The microfluidic system is composed of a mixing unit and a NP assembly unit. The mixing unit consists of a multi-inlet, 2-layer mixer where different precursors such as polymers of different MW and charge, ligand- and drug-conjugated polymers, free drugs, and solvents are mixed at different ratios into a homogenous solution. In the assembly unit, the precursor solution is quickly mixed with an anti-solvent (i.e. water) using 3D hydrodynamic flow focusing where NPs self-assemble after complete mixing. With the microfluidic platform, a library of 100 NPs with different sizes (15-200nm), charge (-30 to +30mV), surface chemistry (i.e. PEG coverage), surface ligand density (0-2.510⁵ ligands/[mu]m²), and drug loading (0-5 w/w%) was producedd in a high-throughput manner by simply varying the flow ratios of precursors entering the system. This library was implemented for (i) screening for formulations (in vitro and in vivo) with optimal clinical properties for cancer treatment and (ii) deepening the understanding of how NP properties affect their biological behavior. The platform developed in this work would likely lead to better understanding of the design parameters for polymeric NPs and their smoother transition to the clinic.by Pedro M. Valencia.Ph.D

Synthesis, characterization and performance of robust poison-resistant ultrathin film yttria stabilized zirconia – nickel anodes for application in solid electrolyte fuel cells

We report on the synthesis of undoped ∼5 μm YSZ-Ni porous thin films prepared by reactive pulsed DC magnetron sputtering at an oblique angle of incidence. Pre-calcination of the amorphous unmodified precursor layers followed by reduction produces a film consisting of uniformly distributed tilted columnar aggregates having extensive three-phase boundaries and favorable gas diffusion characteristics. Similarly prepared films doped with 1.2 at.% Au are also porous and contain highly dispersed gold present as Ni-Au alloy particles whose surfaces are strongly enriched with Au. With hydrogen as fuel, the performance of the undoped thin film anodes is comparable to that of 10–20 times thicker typical commercial anodes. With a 1:1 steam/carbon feed, the un-doped anode cell current rapidly falls to zero after 60 h. In striking contrast, the initial performance of the Au-doped anode is much higher and remains unaffected after 170 h. Under deliberately harsh conditions the performance of the Au-doped anodes decreases progressively, almost certainly due to carbon deposition. Even so, the cell maintains some activity after 3 days operation in dramatic contrast with the un-doped anode, which stops working after only three hours of use. The implications and possible practical application of these findings are discussed.European Union 298300Ministerio de Economía y Competitividad MAT2013‐40852R, 201560E05

Synergistic cytotoxicity of irinotecan and cisplatin in dual-drug targeted polymeric nanoparticles

Aim: Two unexplored aspects for irinotecan and cisplatin (I&C) combination chemotherapy are: actively targeting both drugs to a specific diseased cell type, and delivering both drugs on the same vehicle to ensure their synchronized entry into the cell at a well-defined ratio. In this work, the authors report the use of targeted polymeric nanoparticles (NPs) to coencapsulate and deliver I&C to cancer cells expressing the prostate-specific membrane antigen. Materials & methods: Targeted NPs were prepared in a single step by mixing four different precursors inside microfluidic devices. Results: I&C were encapsulated in 55-nm NPs and showed an eightfold increase in internalization by prostate-specific membrane antigen-expressing LNCaP cells compared with nontargeted NPs. NPs coencapsulating both drugs exhibited strong synergism in LNCaP cells with a combination index of 0.2. Conclusion: The strategy of coencapsulating both I&C in a single NP targeted to a specific cell type could potentially be used to treat different types of cancer.Prostate Cancer Foundation (Nanotherapeutics Award)MIT-Harvard Center of Cancer Nanotechnology Excellence (U54-CA151884)National Science Foundation (U.S.). Graduate Research Fellowship ProgramAmerican Society for Engineering Education. National Defense Science and Engineering Graduate Fellowshi

Microfluidic Platform for Combinatorial Synthesis and Optimization of Targeted Nanoparticles for Cancer Therapy

Taking a nanoparticle (NP) from discovery to clinical translation has been slow compared to small molecules, in part by the lack of systems that enable their precise engineering and rapid optimization. In this work we have developed a microfluidic platform for the rapid, combinatorial synthesis and optimization of NPs. The system takes in a number of NP precursors from which a library of NPs with varying size, surface charge, target ligand density, and drug load is produced in a reproducible manner. We rapidly synthesized 45 different formulations of poly(lactic-co-glycolic acid)-b-poly(ethylene glycol) NPs of different size and surface composition and screened and ranked the NPs for their ability to evade macrophage uptake in vitro. Comparison of the results to pharmacokinetic studies in vivo in mice revealed a correlation between in vitro screen and in vivo behavior. Next, we selected NP synthesis parameters that resulted in longer blood half-life and used the microfluidic platform to synthesize targeted NPs with varying targeting ligand density (using a model targeting ligand against cancer cells). We screened NPs in vitro against prostate cancer cells as well as macrophages, identifying one formulation that exhibited high uptake by cancer cells yet similar macrophage uptake compared to nontargeted NPs. In vivo, the selected targeted NPs showed a 3.5-fold increase in tumor accumulation in mice compared to nontargeted NPs. The developed microfluidic platform in this work represents a tool that could potentially accelerate the discovery and clinical translation of NPs.Prostate Cancer Foundation (Award in Nanotherapeutics)National Cancer Institute (U.S.) (Center of Cancer Nanotechnology Excellence at MIT-Harvard U54-CA151884National Heart, Lung, and Blood Institute (Programs of Excellence in Nanotechnology HHSN268201000045C)National Science Foundation (U.S.). Graduate Research FellowshipAmerican Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipNational Cancer Institute (U.S.) (Center of Cancer Nanotechnology Excellence. Graduate Research Fellowship

Interrelationship between different loads in resisted sprints, half-squat 1RM, and kinematic variables in trained athletes

Resisted sprint running is a common training method for improving sprint-specific strength. It is well-known that an athlete's time to complete a sled-towing sprint increases linearly with increasing sled load. However, to our knowledge, the relationship between the maximum load in sled-towing sprint and the sprint time is unknown, The main purpose of this research was to analyze the relationship between the maximum load in sled-towing sprint, half-squat maximal dynamic strength and the velocity in the acceleration phase in 20-m sprint. A second aim was to compare sprint performance when athletes ran under different conditions: un-resisted and towing sleds. Twenty-one participants (17.86±2.27 years; 1.77±0.06 m and 69.24±7.20 kg) completed a one repetition maximum test (1 RM) from a half-squat position (159.68±22.61 kg) and a series of sled-towing sprints with loads of 0, 5, 10, 15, 20, 25, 30% body mass (Bm) and the maximum resisted sprint load. No significant correlation (P<0.05) was found between half-squat 1 RM and the sprint time in different loaded conditions. Conversely, significant correlations (P<0.05) were found between maximum load in resisted sprint and sprint time (20-m sprint time, r=−0.71; 5% Bm, r=−0.73; 10% Bm, r=−0.53; 15% Bm, r=−0.55; 20% Bm, r=−0.65; 25% Bm, r=−0.44; 30% Bm, r=−0.63; MaxLoad, r= 0.93). The sprinting velocity significantly decreased by 4–22% with all load increases. Stride length (SL) also decreased (17%) significantly across all resisted conditions. In addition, there were significant differences in stride frequency (SF) with loads over 15% Bm. It could be concluded thatthe knowledge of the individual maximal load in resisted sprint and the effects on the sprinting kinematic with different loads, could be interesting to determinate the optimal load to improve the acceleration phase at sprint running.Actividad Física y Deport

Optical Gas Sensing of Ammonia and Amines Based on Protonated Porphyrin/TiO2 Composite Thin Films

Open porous and transparent microcolumnar structures of TiO2 prepared by physical vapour deposition in glancing angle configuration (GLAD-PVD) have been used as host matrices for two different fluorescent cationic porphyrins, 5-(N-methyl 4-pyridyl)-10,15,20-triphenyl porphine chloride (MMPyP) and meso-tetra (N-methyl 4-pyridyl) porphine tetrachloride (TMPyP). The porphyrins have been anchored by electrostatic interactions to the microcolumns by self-assembly through the dip-coating method. These porphyrin/TiO2 composites have been used as gas sensors for ammonia and amines through previous protonation of the porphyrin with HCl followed by subsequent exposure to the basic analyte. UV–vis absorption, emission, and time-resolved spectroscopies have been used to confirm the protonation–deprotonation of the two porphyrins and to follow their spectral changes in the presence of the analytes. The monocationic porphyrin has been found to be more sensible (up to 10 times) than its tetracationic counterpart. This result has been attributed to the different anchoring arrangements of the two porphyrins to the TiO2 surface and their different states of aggregation within the film. Finally, there was an observed decrease of the emission fluorescence intensity in consecutive cycles of exposure and recovery due to the formation of ammonium chloride inside the film.We thank the Junta de Andalucía (Project: FQM-2310), the European Regional Development Funds program (EU-FEDER) and the Spanish Ministry of Economy and Competitiveness (Projects: MAT2013-40852-R, MAT2013-42900-P, MAT2014-57652-C2-2-R, MAT2015-69035-REDC, MINECO-CSIC 201560E055, PCIN-2015-169-C02-02 under a 2014 M-Era.Net project and RECUPERA 2020), for financial support. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

TreeDet: a web server to explore sequence space

The TreeDet (Tree Determinant) Server is the first release of a system designed to integrate results from methods that predict functional sites in protein families. These methods take into account the relation between sequence conservation and evolutionary importance. TreeDet fully analyses the space of protein sequences in either user-uploaded or automatically generated multiple sequence alignments. The methods implemented in the server represent three main classes of methods for the detection of family-dependent conserved positions, a tree-based method, a correlation based method and a method that employs a principal component analyses coupled to a cluster algorithm. An additional method is provided to highlight the reliability of the position in the alignments. The server is available at

Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase

Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s-1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s-1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration.Actividad Física y Deport

Microfluidic technologies for accelerating the clinical translation of nanoparticles

Using nanoparticles for therapy and imaging holds tremendous promise for the treatment of major diseases such as cancer. However, their translation into the clinic has been slow because it remains difficult to produce nanoparticles that are consistent ‘batch-to-batch’, and in sufficient quantities for clinical research. Moreover, platforms for rapid screening of nanoparticles are still lacking. Recent microfluidic technologies can tackle some of these issues, and offer a way to accelerate the clinical translation of nanoparticles. In this Progress Article, we highlight the advances in microfluidic systems that can synthesize libraries of nanoparticles in a well-controlled, reproducible and high-throughput manner. We also discuss the use of microfluidics for rapidly evaluating nanoparticles in vitro under microenvironments that mimic the in vivo conditions. Furthermore, we highlight some systems that can manipulate small organisms, which could be used for evaluating the in vivo toxicity of nanoparticles or for drug screening. We conclude with a critical assessment of the near- and long-term impact of microfluidics in the field of nanomedicine

Spontaneous Formation of Heterogeneous Patches on Polymer-Lipid Core-Shell Particle Surfaces during Self-Assembly

Spontaneous formation of heterogeneous patches on the surface of lipid-based nanoparticles (NPs) and microparticles (MPs) due to the segregation of two different functional groups. Patch formation is observed when tracing the functional groups with quantum dots, gold nanoparticles, and fluorescent dyes. This discovery could have important implications for the future design of self-assembled NPs and MPs for different biomedical applications