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1.
J Am Chem Soc ; 145(43): 23519-23526, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37862238

ABSTRACT

Conjugated macromolecules have a rich history in chemistry, owing to their chemical arrangements that intertwine physical and electronic properties. The continuing study and application of these systems, however, necessitates the development of atomically precise models that bridge the gap between molecules, polymers, and/or their blends. One class of conjugated polymers that have facilitated the advancement of structure-property relationships is discrete, precision oligomers that have remained an outstanding synthetic challenge with only a handful of reported examples. Here we show the first synthesis of molecular dyads featuring sequence-defined oligothiophene donors covalently linked a to small-molecule acceptor. These dyads serve as a platform for probing complex photophysical interactions involving sequence-defined oligomers. This assessment is facilitated through the unprecedented control of oligothiophene length- and sequence-dependent arrangement relative to the acceptor unit, made possible by the incorporation of hydroxyl-containing side chains at precise positions along the backbone through sequence-defined oligomerizations. We show that both the oligothiophene sequence and length play complementary roles in determining the transfer efficiency of photoexcited states. Overall, the work highlights the importance of the spatial arrangement of donor-acceptor systems that are commonly studied for a range of uses, including light harvesting and photocatalysis.

2.
Toxins (Basel) ; 15(9)2023 09 04.
Article in English | MEDLINE | ID: mdl-37755973

ABSTRACT

Reliable models of renal failure in large animals are critical to the successful translation of the next generation of renal replacement therapies (RRT) into humans. While models exist for the induction of renal failure, none are optimized for the implantation of devices to the retroperitoneal vasculature. We successfully piloted an embolization-to-implantation protocol enabling the first implant of a silicon nanopore membrane hemodialyzer (SNMHD) in a swine renal failure model. Renal arterial embolization is a non-invasive approach to near-total nephrectomy that preserves retroperitoneal anatomy for device implants. Silicon nanopore membranes (SNM) are efficient blood-compatible membranes that enable novel approaches to RRT. Yucatan minipigs underwent staged bilateral renal arterial embolization to induce renal failure, managed by intermittent hemodialysis. A small-scale arteriovenous SNMHD prototype was implanted into the retroperitoneum. Dialysate catheters were tunneled externally for connection to a dialysate recirculation pump. SNMHD clearance was determined by intermittent sampling of recirculating dialysate. Creatinine and urea clearance through the SNMHD were 76-105 mL/min/m2 and 140-165 mL/min/m2, respectively, without albumin leakage. Normalized creatinine and urea clearance measured in the SNMHD may translate to a fully implantable clinical-scale device. This pilot study establishes a path toward therapeutic testing of the clinical-scale SNMHD and other implantable RRT devices.


Subject(s)
Kidneys, Artificial , Renal Insufficiency , Humans , Swine , Animals , Creatinine , Pilot Projects , Silicon , Swine, Miniature , Dialysis Solutions , Urea
3.
J Chem Phys ; 159(7)2023 Aug 21.
Article in English | MEDLINE | ID: mdl-37602803

ABSTRACT

PbS semiconductor nanocrystals (NCs) have been heavily explored for infrared optoelectronics but can exhibit visible-wavelength quantum-confined optical gaps when sufficiently small (⌀ = 1.8-2.7 nm). However, small PbS NCs traditionally exhibited very broad ensemble absorption linewidths, attributed to poor size-heterogeneity. Here, harnessing recent synthetic advances, we report photophysical measurements on PbS ensembles that span this underexplored size range. We observe that the smallest PbS NCs pervasively exhibit lower brightness and anomalously accelerated photoluminescence decays-relative to the idealized photophysical models that successfully describe larger NCs. We find that effects of residual ensemble size-heterogeneity are insufficient to explain our observations, so we explore plausible processes that are intrinsic to individual nanocrystals. Notably, the anomalous decay kinetics unfold, surprisingly, over hundreds-of-nanosecond timescales. These are poorly matched to effects of direct carrier trapping or fine-structure thermalization but are consistent with non-radiative recombination linked to a dynamic surface. Thus, the progressive enhancement of anomalous decay in the smallest particles supports predictions that the surface plays an outsized role in exciton-phonon coupling. We corroborate this claim by showing that the anomalous decay is significantly remedied by the installation of a rigidifying shell. Intriguingly, our measurements show that the anomalous aspect of these kinetics is insensitive to temperature between T = 298 and 77 K, offering important experimental constraint on possible mechanisms involving structural fluctuations. Thus, our findings identify and map the anomalous photoluminescence kinetics that become pervasive in the smallest PbS NCs and call for targeted experiments and theory to disentangle their origin.

4.
Nano Lett ; 23(11): 4837-4843, 2023 Jun 14.
Article in English | MEDLINE | ID: mdl-37191568

ABSTRACT

Energy transfer processes may be engineered in van der Waals heterostructures by taking advantage of the atomically abrupt, Å-scale, and topologically tailorable interfaces within them. Here, we prepare heterostructures comprised of 2D WSe2 monolayers interfaced with dibenzotetraphenylperiflanthene (DBP)-doped rubrene, an organic semiconductor capable of triplet fusion. We fabricate these heterostructures entirely through vapor deposition methods. Time-resolved and steady-state photoluminescence measurements reveal rapid subnanosecond quenching of WSe2 emission by rubrene and fluorescence from guest DBP molecules at 612 nm (λexc = 730 nm), thus providing clear evidence of photon upconversion. The dependence of the upconversion emission on excitation intensity is consistent with a triplet fusion mechanism, and maximum efficiency (linear regime) of this process occurs at threshold intensities as low as 110 mW/cm2, which is comparable to the integrated solar irradiance. This study highlights the potential for advanced optoelectronic applications employing vdWHs which leverage strongly bound excitons in monolayer TMDs and organic semiconductors.

5.
Adv Mater ; 35(28): e2301842, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37170473

ABSTRACT

III-V colloidal quantum dots (CQDs) are promising materials for optoelectronic applications, for they avoid heavy metals while achieving absorption spanning the visible to the infrared (IR). However, the covalent nature of III-V CQDs requires the development of new passivation strategies to fabricate conductive CQD solids for optoelectronics: this work shows herein that ligand exchanges, previously developed in II-VI and IV-VI quantum dots and employing a single ligand, do not fully passivate CQDs, and that this curtails device efficiency. Guided by density functional theory (DFT) simulations, this work develops a co-passivation strategy to fabricate indium arsenide CQD photodetectors, an approach that employs the combination of X-type methyl ammonium acetate (MaAc) and Z-type ligands InBr3 . This approach maintains charge carrier mobility and improves passivation, seen in a 25% decrease in Stokes shift, a fourfold reduction in the rate of first-exciton absorption linewidth broadening over time-under-stress, and leads to a doubling in photoluminescence (PL) lifetime. The resulting devices show 37% external quantum efficiency (EQE) at 950 nm, the highest value reported for InAs CQD photodetectors.


Subject(s)
Quantum Dots , Ligands , Electric Conductivity
6.
Small ; 19(36): e2302173, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37116124

ABSTRACT

The tetratopic linker, 1,3,6,8-tetrakis(p-benzoic acid)pyrene (H4 TBAPy) along with rare-earth (RE) ions is used for the synthesis of 9 isostructures of a metal-organic framework (MOF) with shp topology, named RE-CU-10 (RE = Y(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III), and Lu(III)). The synthesis of each RE-CU-10 analogue requires different reaction conditions to achieve phase pure products. Single crystal X-ray diffraction indicates the presence of a RE9 -cluster in Y- to Tm-CU-10, while a RE11 -cluster is observed for Yb- and Lu-CU-10. The photooxidation performance of RE-CU-10 analogues is evaluated, observing competition between linker-to-metal energy transfer versus the generation of singlet oxygen. The singlet oxygen produced is used to detoxify a mustard gas simulant 2-chloroethylethyl sulfide, with half-lives ranging from 4.0 to 5.8 min, some of the fastest reported to date using UV-irradiation and < 1 mol% catalyst, in methanol under O2 saturation.

7.
J Phys Chem Lett ; 14(7): 1899-1909, 2023 Feb 23.
Article in English | MEDLINE | ID: mdl-36780580

ABSTRACT

Nanocrystal (NC)-sensitized triplet-fusion upconversion is a rising strategy to convert long-wavelength, incoherent light into higher-energy output photons. Here, we chart the photophysics of tailor-functionalized CdSe NCs to understand energy transfer to surface-anchored transmitter ligands, which can proceed via correlated exciton transfer or sequential carrier hops. Varying NC size, we observe a pronounced acceleration of energy transfer (from kquench = 0.0096 ns-1 ligand-1 to 0.064 ns-1 ligand-1) when the barrier to hole-first sequential transfer is lowered from 100 ± 25 meV to 50 ± 25 meV. This acceleration is 5.1× the expected effect of increased carrier wave function leakage, so we conclude that sequential transfer becomes kinetically dominant under the latter conditions. Last, transient photoluminescence shows that NC band-edge and trap states are comparably quenched by functionalization (up to ∼98% for sequential transfer) and exhibit matched dynamics for t > 300 ns, consistent with a dynamic quasi-equilibrium where photoexcitations can ultimately be extracted even when a carrier is initially trapped.

8.
Expert Rev Med Devices ; 19(10): 763-778, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36373162

ABSTRACT

INTRODUCTION: Image-guided endovascular interventions, performed using the insertion and navigation of catheters through the vasculature, have been increasing in number over the years, as minimally invasive procedures continue to replace invasive surgical procedures. Such endovascular interventions are almost exclusively performed under x-ray fluoroscopy, which has the best spatial and temporal resolution of all clinical imaging modalities. Magnetic resonance imaging (MRI) offers unique advantages and could be an attractive alternative to conventional x-ray guidance, but also brings with it distinctive challenges. AREAS COVERED: In this review, the benefits and limitations of MRI-guided endovascular interventions are addressed, systems and devices for guiding such interventions are summarized, and clinical applications are discussed. EXPERT OPINION: MRI-guided endovascular interventions are still relatively new to the interventional radiology field, since significant technical hurdles remain to justify significant costs and demonstrate safety, design, and robustness. Clinical applications of MRI-guided interventions are promising but their full potential may not be realized until proper tools designed to function in the MRI environment are available. Translational research and further preclinical studies are needed before MRI-guided interventions will be practical in a clinical interventional setting.


Subject(s)
Catheters , Magnetic Resonance Imaging , Humans
9.
Chem Commun (Camb) ; 58(62): 8630-8633, 2022 Aug 02.
Article in English | MEDLINE | ID: mdl-35833569

ABSTRACT

A novel redox-active fluorene monomer is synthesized and copolymerized with 9,9-dioctylfluorene and benzo[c][1,2,5]thiadiazole via Suzuki cross-coupling to produce alternating and tertiary copolymers. Electrochemical and chemical reduction of the copolymers generates organic polymeric radical anions. Electrochemical, spectroscopic, and photophysical characterization grant insight into the structure-property relationship for open-shell conjugated polymers.

10.
J Vasc Interv Radiol ; 33(6): 687-694, 2022 06.
Article in English | MEDLINE | ID: mdl-35301127

ABSTRACT

PURPOSE: To evaluate radiolabeled doxorubicin (Dox) analogs as tracers of baseline Dox biodistribution in vivo during hepatic intra-arterial chemotherapy and to assess the efficacy of ChemoFilter devices to bind Dox in vitro. MATERIALS AND METHODS: In an in vitro static experiment, [fluorine-18]N-succinimidyl 4-fluorobenzoate ([18F]SFB) and [fluorine-18]fluorobenzoyl-doxorubicin ([18F]FB-Dox) were added to a beaker containing a filter material (Dowex cation exchange resin, single-stranded DNA (ssDNA) resin, or sulfonated polymer coated mesh). In an in vitro flow model, [18F]FB-Dox was added into a Dox solution in phosphate-buffered saline, and the solution flowed via a syringe column containing the filter materials. In an in vitro flow experiment, using micro-positron emission tomography (PET), images were taken as [18F]SFB and [18F]FB-Dox moved through a phantom. For in vivo biodistribution testing, a catheter was placed into the common hepatic artery of a swine, and [18F]FB-Dox was infused over 30 seconds. A 10-minute dynamic image and three 20-minute static images were acquired using 3T PET/MR imaging. RESULTS: In the in vitro static experiment, [18F]FB-Dox demonstrated 76.7%, 88.0%, and 52.4% binding to the Dowex resin, ssDNA resin, and coated mesh, respectively. In the in vitro flow model, the first-pass binding of [18F]FB-Dox to the Dowex resin, ssDNA resin, and coated mesh was 76.7%, 74.2%, and 76.2%, respectively, and the total bound fraction was 80.9%, 84.6%, and 79.9%, respectively. In the in vitro flow experiment using micro-PET, the phantom demonstrated a greater amount of [18F]FB-Dox bound to both filter cartridges than of the control [18F]SFB. In in vivo biodistribution testing, the first 10 minutes depicted [18F]FB-Dox moving through the right upper quadrant of the abdomen. A region-of-interest analysis showed that the relative amount increased by 2.97 times in the gallbladder and 1.08 times in the kidney. The amount decreased by 0.74 times in the brain and 0.57 times in the heart. CONCLUSIONS: [18F]FB-Dox can be used to assess Dox binding to ChemoFilters as well as in vivo biodistribution. This sets the stage for the evaluation of ChemoFilter effectiveness in reducing systemic toxicity from intra-arterial chemotherapy.


Subject(s)
Doxorubicin , Positron-Emission Tomography , Animals , Hepatic Artery , Humans , Magnetic Resonance Imaging , Positron-Emission Tomography/methods , Swine , Tissue Distribution
11.
J Urol ; 207(5): 1077-1085, 2022 05.
Article in English | MEDLINE | ID: mdl-34981946

ABSTRACT

PURPOSE: We evaluated angioembolization (AE) use for high-grade renal trauma (HGRT) management and compared AE vs surgical repair (SR) in requiring nephrectomy. MATERIALS AND METHODS: Using National Trauma Data Bank® 2013-2018, we identified patients with HGRT who underwent AE or SR as initial management. Therapy failure was defined as performing subsequent nephrectomy, partial nephrectomy, SR or AE. Logistic regression was performed to assess the association between intervention type (AE vs SR) and nephrectomy. Analysis was repeated in a propensity score-matched cohort constructed by matching AE to SR patients on American Association for the Surgery of Trauma (AAST) grade, injury mechanism (blunt vs penetrating) and hemodynamic instability (systolic blood pressure <90 mmHg). RESULTS: There were 266 patients in the AE group and 215 in the SR group. Median age was 29.5 years and 212 patients (44.1%) had penetrating injuries. AE was successful in 94.2% and 85.3% of grade IV and V injuries, respectively, whereas SR was successful in 82.1% and 56%, respectively. Grade V injury was associated with AE failure in the adjusted analysis (OR 3.55, 95% CI 1.22-10.2, p=0.02). Nephrectomy was less likely to be performed after AE vs after SR in HGRT (6.4% vs 17.2%, p=0.01), AAST grade IV (4.2% vs 13.7%, p=0.001) and AAST grade V (12% vs 44%, p=0.001). The matched cohort comprised 528 patients. In post-match regression, AE, compared to SR, was associated with lower odds of nephrectomy (OR 0.18, 95% CI 0.04-0.70, p=0.013). CONCLUSIONS: AE achieved superior kidney salvage compared to SR in this observational cohort. These results inform both clinical practice and future prospective trials.


Subject(s)
Kidney , Wounds, Nonpenetrating , Adult , Hospitals , Humans , Injury Severity Score , Kidney/injuries , Kidney/surgery , Registries , Retrospective Studies , Wounds, Nonpenetrating/surgery
12.
Chem Sci ; 12(42): 14111-14120, 2021 Nov 03.
Article in English | MEDLINE | ID: mdl-34760195

ABSTRACT

Photon upconversion is a strategy to generate high-energy excitations from low-energy photon input, enabling advanced architectures for imaging and photochemistry. Here, we show that ultra-small PbS nanocrystals can sensitize red-to-blue triplet-fusion upconversion with a large anti-Stokes shift (ΔE = 1.04 eV), and achieve max-efficiency upconversion at near-solar fluences (I th = 220 mW cm-2) despite endothermic triplet sensitization. This system facilitates the photo-initiated polymerization of methyl methacrylate using only long-wavelength light (λ exc: 637 nm); a demonstration of nanocrystal-sensitized upconversion photochemistry. Time-resolved spectroscopy and kinetic modelling clarify key loss channels, highlighting the benefit of long-lifetime nanocrystal sensitizers, but revealing that many (48%) excitons that reach triplet-extracting carboxyphenylanthracene ligands decay before they can transfer to free-floating acceptors-emphasizing the need to address the reduced lifetimes that we determine for molecular triplets near the nanocrystal surface. Finally, we find that the inferred thermodynamics of triplet sensitization from these ultra-small PbS quantum dots are surprisingly favourable-completing an advantageous suite of properties for upconversion photochemistry-and do not vary significantly across the ensemble, which indicates minimal effects from nanocrystal heterogeneity. Together, our demonstration and study of red-to-blue upconversion using ultra-small PbS nanocrystals in a quasi-equilibrium, mildly endothermic sensitization scheme offer design rules to advance implementations of triplet fusion, especially where large anti-Stokes wavelength shifts are sought.

13.
ACS Nano ; 15(11): 18085-18099, 2021 Nov 23.
Article in English | MEDLINE | ID: mdl-34705409

ABSTRACT

Kesterite Cu2ZnSnS4 (k-CZTS) nanocrystals have received attention for their tunable optoelectronic properties, as well as the earth abundance of their constituent atoms. However, the phase-pure synthesis of these quaternary NCs is challenging due to their polymorphism, as well as the undesired formation of related binary and ternary impurities. A general synthetic route to tackle this complexity is to pass through intermediate template nanocrystals that direct subsequent cation exchange toward the desired quaternary crystalline phase, particularly those that are thermodynamically disfavored or otherwise synthetically challenging. Here, working within this model multinary system, we achieve control over the formation of three binary copper sulfide polymorphs, cubic digenite (Cu1.8S), hexagonal covellite (CuS), and monoclinic djurleite (Cu1.94S). Controlled experiments with Cu0 seeds show that selected binary phases can be favored by the identity and stoichiometry of the sulfur precursor alone under otherwise comparable reaction conditions. We then demonstrate that the nature of the Cu2-xS template dictates the final polymorph of the CZTS nanocrystal products. Through digenite, the cation exchange reaction readily yields the k-CZTS phase due to its highly similar anion sublattice. Covellite nanocrystals template the k-CZTS phase but via major structural rearrangement to digenite that requires elevated temperatures in the absence of a strong reducing agent. In contrast, we show that independently synthesized djurleite nanorods template the formation of the wurtzite polymorph (w-CZTS) but with prominent stacking faults in the final product. Applying this refined understanding to the standard one-pot syntheses of k- and w-CZTS nanocrystals, we identify that these reactions are each effectively templated by binary intermediates formed in situ, harnessing their properties to guide the overall synthesis of phase-pure quaternary materials. Our results provide tools for the careful development of tailored nanocrystal syntheses in complex polymorphic systems.

14.
Radiology ; 299(1): 167-176, 2021 04.
Article in English | MEDLINE | ID: mdl-33560189

ABSTRACT

Background For patients with acute ischemic stroke undergoing endovascular mechanical thrombectomy with x-ray angiography, the use of adjuncts to maintain vessel patency, such as stents or antiplatelet medications, can increase risk of periprocedural complications. Criteria for using these adjuncts are not well defined. Purpose To evaluate use of MRI to guide critical decision making by using a combined biplane x-ray neuroangiography 3.0-T MRI suite during acute ischemic stroke intervention. Materials and Methods This retrospective observational study evaluated consecutive patients undergoing endovascular intervention for acute ischemic stroke between July 2019 and May 2020 who underwent either angiography with MRI or angiography alone. Cerebral tissue viability was assessed by using MRI as the reference standard. For statistical analysis, Fisher exact test and Student t test were used to compare groups. Results Of 47 patients undergoing acute stroke intervention, 12 patients (median age, 69 years; interquartile range, 60-77 years; nine men) underwent x-ray angiography with MRI whereas the remaining 35 patients (median age, 80 years; interquartile range, 68-86 years; 22 men) underwent angiography alone. MRI results influenced clinical decision making in one of three ways: whether or not to perform initial or additional mechanical thrombectomy, whether or not to place an intracranial stent, and administration of antithrombotic or blood pressure medications. In this initial experience, decision making during endovascular acute stroke intervention in the combined angiography-MRI suite was better informed at MRI, such that therapy was guided in real time by the viability of the at-risk cerebral tissue. Conclusion Integrating intraprocedural 3.0-T MRI into acute ischemic stroke treatment was feasible and guided decisions of whether or not to continue thrombectomy, to place stents, or to administer antithrombotic medication or provide blood pressure medications. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Lev and Leslie-Mazwi in this issue.


Subject(s)
Cerebral Angiography/methods , Decision Making , Ischemic Stroke/diagnostic imaging , Ischemic Stroke/surgery , Magnetic Resonance Imaging/methods , Stroke/diagnostic imaging , Stroke/surgery , Thrombectomy/methods , Aged , Female , Humans , Infant, Newborn , Intraoperative Period , Male , Middle Aged , Retrospective Studies
15.
J Phys Chem Lett ; 11(15): 6404-6412, 2020 Aug 06.
Article in English | MEDLINE | ID: mdl-32787286

ABSTRACT

Colloidal quantum dots (QDs) suffer from pervasive photoluminescence intermittency that frustrates applications and correlates with irreversible photodegradation. In single-QD spectroscopies, blinking manifests as sporadic switching between ON and OFF states without a characteristic time scale, and the longstanding search for mechanisms has been recently accelerated by techniques to controllably modulate the QD environment. Here, we develop an all-optical modulation scheme and demonstrate that sub-bandgap light tuned to the stimulated emission transition perturbs the blinking statistics of individual CdSe/ZnS core/shell QDs. Resonant optical modulation progressively suppresses long-duration ON events, quantified by a power-law slope that is more negative on average (ΔαON = 0.46 ± 0.09), while OFF distributions and truncation times are unaffected. This characteristic effect is robust to choices in background subtraction and statistical analysis but supports mechanistic descriptions beyond first-order kinetics. This demonstration of all-optical perturbation of QD blinking dynamics provides an experimental avenue to disentangle the complex photophysics of photoluminescence intermittency.

16.
IEEE Trans Biomed Eng ; 67(3): 876-882, 2020 03.
Article in English | MEDLINE | ID: mdl-31247538

ABSTRACT

Interventional magnetic resonance imaging (MRI) could allow for diagnosis and immediate treatment of ischemic stroke; however, such endovascular catheter-based procedures under MRI guidance are inherently difficult. One major challenge is tracking the tip of the catheter, as standard fabrication methods for building inductively coupled coil markers are rigid and bulky. Here, we report a new approach that uses aerosol jet deposition to three-dimensional (3-D) print an inductively coupled RF coil marker on a polymer catheter. Our approach enables lightweight conforming markers on polymer catheters and these low-profile markers allow the catheter to be more safely navigated in small caliber vessels. Prototype markers with an inductor with the geometry of a double helix are incorporated on catheters for in vitro studies, and we show that these markers exhibit good signal amplification. We report temperature measurements and, finally, demonstrate feasibility in a preliminary in vivo experiment. We provide material properties and electromagnetic simulation performance analysis. This paper presents fully aerosol jet-deposited and functional wireless resonant markers on polymer catheters for use in 3T clinical scanners.


Subject(s)
Catheters , Magnetic Resonance Imaging, Interventional/instrumentation , Magnetic Resonance Imaging, Interventional/methods , Wireless Technology/instrumentation , Animals , Equipment Design , Female , Swine , Temperature
17.
J Phys Chem Lett ; 10(23): 7463-7469, 2019 Dec 05.
Article in English | MEDLINE | ID: mdl-31751145

ABSTRACT

We demonstrate that a structurally rigid, weakly coupled molecular dimer can replace traditional monomeric annihilators for triplet fusion upconversion (TUC) in solution by observing emitted photons (λ = 540 nm) from a norbornyl-bridged tetracene homodimer following excitation of a triplet sensitizer at λ = 730 nm. Intriguingly, steady-state spectroscopy, kinetic simulations, and Stern-Volmer quenching experiments show that the dimer exhibits qualitatively different photophysics than its parent monomer: it is less effective at diffusion-mediated triplet exciton transfer, but it fuses extracted triplets more efficiently. Our results support the development of composite triplet-fusion platforms that go beyond diffusion-mediated triplet extraction, ultimately circumventing the concentration dependence of solution-phase TUC.

18.
J Phys Chem Lett ; 10(19): 5897-5901, 2019 Oct 03.
Article in English | MEDLINE | ID: mdl-31536364

ABSTRACT

The use of excess PbCl2 in the synthesis of PbS nanocrystals has become a convenient route to produce narrow-line-width infrared emitters. However, these materials have found limited adoption in optoelectronic devices-even compared to PbS nanocrystals prepared with lead oleate. Here, using both transmission electron microscopy and small-angle X-ray scattering, we show that excess PbCl2 results in larger-diameter PbS nanocrystals for the same excitonic features, which is consistent with the formation of an intrinsic insulating shell. We observe further differences in excess-lead-chloride nanocrystals consistent with a shell, including lattice strain and smaller Stokes shifts for intermediate sizes (⌀: 4.8-6.8 nm) that match the passivation/rigidification predicted for a chloride-terminate surface. Our results clarify and rationalize the divergent properties of PbS nanocrystals prepared using different synthetic methodologies, give guidance for device implementation, and offer a new target for synthetic control.

20.
ACS Cent Sci ; 5(3): 419-427, 2019 Mar 27.
Article in English | MEDLINE | ID: mdl-30937369

ABSTRACT

Despite efforts to develop increasingly targeted and personalized cancer therapeutics, dosing of drugs in cancer chemotherapy is limited by systemic toxic side effects. We have designed, built, and deployed porous absorbers for capturing chemotherapy drugs from the bloodstream after these drugs have had their effect on a tumor, but before they are released into the body where they can cause hazardous side effects. The support structure of the absorbers was built using 3D printing technology. This structure was coated with a nanostructured block copolymer with outer blocks that anchor the polymer chains to the 3D printed support structure and a middle block that has an affinity for the drug. The middle block is polystyrenesulfonate which binds to doxorubicin, a widely used and effective chemotherapy drug with significant toxic side effects. The absorbers are designed for deployment during chemotherapy using minimally invasive image-guided endovascular surgical procedures. We show that the introduction of the absorbers into the blood of swine models enables the capture of 64 ± 6% of the administered drug (doxorubicin) without any immediate adverse effects. Problems related to blood clots, vein wall dissection, and other biocompatibility issues were not observed. This development represents a significant step forward in minimizing toxic side effects of chemotherapy.

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