@article{song_li_chen_keshavarz_chapman_tracy_mckinley_holten-andersen_2022, title={Dynamics of dual-junction-functionality associative polymer networks with ion and nanoparticle metal-coordinate cross-link junctions}, volume={66}, ISSN={["1520-8516"]}, DOI={10.1122/8.0000410}, abstractNote={We provide a canonical introduction to dual-junction-functionality associative polymer networks, which combine high and low functionality (f) dynamic cross-link junctions to impart load-bearing, dissipation, and self-repairing ability to the network. This unique type of network configuration offers an alternative to traditional dual-junction networks consisting of covalent and reversible cross-links. The high-f junctions can provide load-bearing abilities similar to a covalent cross-link while retaining the ability to self-repair and concurrently confer stimuli-responsive properties arising from the high-f junction species. We demonstrate the mechanical properties of this design motif using metal-coordinating polymer hydrogel networks, which are dynamically cross-linked by different ratios of metal nanoparticle (high-f) and metal ion (low-f) cross-link junctions. We also demonstrate the spontaneous self-assembly of nanoparticle-cross-linked polymers into anisotropic sheets, which may be generalizable for designing dual-junction-functionality associative networks with low volume fraction percolated high-f networks.}, number={6}, journal={JOURNAL OF RHEOLOGY}, author={Song, Jake and Li, Qiaochu and Chen, Pangkuan and Keshavarz, Bavand and Chapman, Brian S. and Tracy, Joseph B. and McKinley, Gareth H. and Holten-Andersen, Niels}, year={2022}, month={Nov}, pages={1333–1345} }
 @article{yadav_rizvi_kuttich_mishra_chapman_lynch_kraus_oldenburg_tracy_2021, title={Plasmon-Coupled Gold Nanoparticles in Stretched Shape-Memory Polymers for Mechanical/Thermal Sensing}, volume={4}, ISSN={["2574-0970"]}, url={https://doi.org/10.1021/acsanm.1c00309}, DOI={10.1021/acsanm.1c00309}, abstractNote={The organization of plasmonic nanoparticles (NPs) determines the strength and polarization dependence of coupling of their surface plasmons. In this study, plasmon coupling of spherical Au NPs with...}, number={4}, journal={ACS APPLIED NANO MATERIALS}, publisher={American Chemical Society (ACS)}, author={Yadav, Prachi R. and Rizvi, Mehedi H. and Kuttich, Bjoern and Mishra, Sumeet R. and Chapman, Brian S. and Lynch, Brian B. and Kraus, Tobias and Oldenburg, Amy L. and Tracy, Joseph B.}, year={2021}, month={Apr}, pages={3911–3921} }
 @article{chapman_mishra_tracy_2019, title={Direct electrospinning of titania nanofibers with ethanol}, volume={48}, ISSN={["1477-9234"]}, url={https://doi.org/10.1039/C9DT01872G}, DOI={10.1039/c9dt01872g}, abstractNote={TiO2 nanofibers with average diameters of ∼70 nm were prepared by direct electrospinning.}, number={34}, journal={DALTON TRANSACTIONS}, publisher={Royal Society of Chemistry (RSC)}, author={Chapman, Brian S. and Mishra, Sumeet R. and Tracy, Joseph B.}, year={2019}, month={Sep}, pages={12822–12827} }
 @article{zhao_steves_chapman_tracy_knappenberger_2018, title={Quantification of Interface-Dependent Plasmon Quality Factors Using Single-Beam Nonlinear Optical Interferometry}, volume={90}, ISSN={["1520-6882"]}, url={https://doi.org/10.1021/acs.analchem.8b04101}, DOI={10.1021/acs.analchem.8b04101}, abstractNote={A method for quantification of plasmon mode quality factors using a novel collinear single-beam interferometric nonlinear optical (INLO) microscope is described. A collinear sequence of phase-stabilized femtosecond laser pulses generated by a series of birefringent optics is used for the INLO experiments. Our experimental designs allow for the creation of pulse replicas (800 nm carrier wave) that exhibit interpulse phase stability of 33 mrad (approximately 14 attoseonds), which can be incrementally temporally delayed from attosecond to picosecond time scales. This temporal tuning range allows for resonant electronic Fourier spectroscopy of plasmonic gold nanoparticles. The collinear geometry of the pulse pair facilitates integration into an optical microscopy platform capable of single-nanoparticle sensitivity. Analysis of the Fourier spectra in the frequency domain yields the sample plasmon resonant response and homogeneous line width; the latter provided quantification of the plasmon mode quality factor. We have applied this INLO approach to quantitatively determine the influence of encapsulation of gold nanorods with silica shells on plasmon quality factors. We have studied a series of three gold nanorod samples, distinguished by surface passivation. These include cetyltrimethylammonium bromide (CTAB)-passivated nanorods, as well as ones encapsulated by 5 and 20 nanometer-thick silica shells. The Q-factor results show a trend of increasing quality factor, increasing by 46% from 54 ± 8 to 79 ± 9, in going from CTAB- to 20 nm silica-coated AuNRs. The straightforward method of INLO enables analysis of plasmon responses to environmental influences, such as analyte binding and solvent effects, as well as quantification of structure-specific plasmon coherence dynamics.}, number={22}, journal={ANALYTICAL CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Zhao, Tian and Steves, Megan A. and Chapman, Brian S. and Tracy, Joseph B. and Knappenberger, Kenneth L., Jr.}, year={2018}, month={Nov}, pages={13702–13707} }
 @article{rowe_chapman_tracy_2018, title={Understanding and Controlling the Morphology of Silica Shells on Gold Nanorods}, volume={30}, ISSN={["1520-5002"]}, url={https://doi.org/10.1021/acs.chemmater.8b00794}, DOI={10.1021/acs.chemmater.8b00794}, abstractNote={Subtle variations in the conditions for addition of a tetraethyl orthosilicate (TEOS)/methanol (MeOH) solution to gold nanorods (GNRs) stabilized by cetyltrimethylammonium bromide (CTAB) allow for morphological control of silica (SiO2) shells deposited onto the GNRs. The concentration of TEOS in the TEOS/MeOH mixture determines whether the SiO2 shell uniformly coats whole GNRs or forms lobes on the ends of the GNRs. Changes in the optical absorbance spectrum of SiO2-coated GNRs (SiO2-GNRs) after purification with MeOH suggest CTAB can be removed by dissolution through the porous SiO2 shells. The size of the SiO2 lobes can be controlled, but there is a minimum lobe size, below which full encapsulation is favored. The following mechanism of lobe formation is proposed: Initially, a SiO2 shell fully encapsulates the CTAB-stabilized GNR core. Under optimized reaction conditions, determined by the MeOH concentration, the SiO2 shells can reshape into lobes, which requires sufficient solubility of SiO2 and damage...}, number={18}, journal={CHEMISTRY OF MATERIALS}, publisher={American Chemical Society (ACS)}, author={Rowe, Laurel R. and Chapman, Brian S. and Tracy, Joseph B.}, year={2018}, month={Sep}, pages={6249–6258} }
 @article{blackmon_kreda_sears_chapman_hill_tracy_ostrowski_oldenburg_2017, title={Direct monitoring of pulmonary disease treatment biomarkers using plasmonic gold nanorods with diffusion-sensitive OCT}, volume={9}, ISSN={["2040-3372"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000399429800007&KeyUID=WOS:000399429800007}, DOI={10.1039/c7nr00376e}, abstractNote={The solid concentration of pulmonary mucus (wt%) is critical to respiratory health. In patients with respiratory disease, such as Cystic Fibrosis (CF) and Chronic Obstructive Pulmonary Disorder (COPD), mucus hydration is impaired, resulting in high wt%. Mucus with high wt% is a hallmark of pulmonary disease that leads to obstructed airways, inflammation, and infection. Methods to measure mucus hydration in situ and in real-time are needed for drug development and personalized therapy. We employed plasmonic gold nanorod (GNR) biosensors that intermittently collide with macromolecules comprising the mucus mesh as they self-diffuse, such that GNR translational diffusion (DT) is sensitive to wt%. GNRs are attractive candidates for bioprobes due to their anisotropic optical scattering that makes them easily distinguishable from native tissue using polarization-sensitive OCT. Using principles of heterodyne dynamic light scattering, we developed diffusion-sensitive optical coherence tomography (DS-OCT) to spatially-resolve changing DT in real-time. DS-OCT enables, for the first time, direct monitoring of changes in nanoparticle diffusion rates that are sensitive to nanoporosity with spatial and temporal resolutions of 4.7 μm and 0.2 s. DS-OCT therefore enables us to measure spatially-resolved changes in mucus wt% over time. In this study, we demonstrate the applicability of DS-OCT on well-differentiated primary human bronchial epithelial cells during a clinical mucus-hydrating therapy, hypertonic saline treatment (HST), to reveal, for the first time, mucus mixing, cellular secretions, and mucus hydration on the micrometer scale that translate to long-term therapeutic effects.}, number={15}, journal={NANOSCALE}, publisher={Royal Society of Chemistry (RSC)}, author={Blackmon, R. L. and Kreda, S. M. and Sears, P. R. and Chapman, B. S. and Hill, D. B. and Tracy, J. B. and Ostrowski, L. E. and Oldenburg, A. L.}, year={2017}, month={Apr}, pages={4907–4917} }
 @article{niu_mcferon_godinez-salomon_chapman_damin_tracy_augustyn_rhodes_2017, title={Enhanced Electrochemical Lithium-Ion Charge Storage of Iron Oxide Nanosheets}, volume={29}, ISSN={["1520-5002"]}, url={https://doi.org/10.1021/acs.chemmater.7b02315}, DOI={10.1021/acs.chemmater.7b02315}, abstractNote={Iron oxides are appealing cathode materials for low-cost electrochemical energy storage, but iron oxide nanoparticles (NPs) exhibit very low capacities, particularly at fast charging and discharging times, which are increasingly important for numerous applications. We report that synthesis and stabilization of iron oxide in nanosheets results in significantly improved lithium-ion charge storage capacities compared to those of iron oxide NPs at both slow and fast charging/discharging times. The iron oxide nanosheets have lateral dimensions of ∼50 nm and thicknesses of ∼1 nm and are composed of smaller crystallites. The structure of the nanosheets is consistent with maghemite, γ-Fe2O3, which contains cation defects. The γ-Fe2O3 phase is not typically observed within a nanosheet form, and γ-Fe2O3 nanosheets transform to NPs at a relatively low temperature of 200 °C. The transformation of γ-Fe2O3 from a nanosheet to an NP occurs in conjunction with removal of structural H2O. The γ-Fe2O3 nanosheets exhibited l...}, number={18}, journal={CHEMISTRY OF MATERIALS}, publisher={American Chemical Society (ACS)}, author={Niu, Sibo and McFeron, Ryan and Godinez-Salomon, Fernando and Chapman, Brian S. and Damin, Craig A. and Tracy, Joseph B. and Augustyn, Veronica and Rhodes, Christopher P.}, year={2017}, month={Sep}, pages={7794–7807} }
 @article{blackmon_kreda_sears_ostrowski_hill_chapman_tracy_oldenburg_2016, title={Diffusion-sensitive optical coherence tomography for real-time monitoring of mucus thinning treatments}, volume={9697}, ISSN={["0277-786X"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000378122900061&KeyUID=WOS:000378122900061}, DOI={10.1117/12.2208805}, abstractNote={Mucus hydration (wt%) has become an increasingly useful metric in real-time assessment of respiratory health in diseases like cystic fibrosis and COPD, with higher wt% indicative of diseased states. However, available in vivo rheological techniques are lacking. Gold nanorods (GNRs) are attractive biological probes whose diffusion through tissue is sensitive to the correlation length of comprising biopolymers. Through employment of dynamic light scattering theory on OCT signals from GNRs, we find that weakly-constrained GNR diffusion predictably decreases with increasing wt% (more disease-like) mucus. Previously, we determined this method is robust against mucus transport on human bronchial epithelial (hBE) air-liquid interface cultures (R2=0.976). Here we introduce diffusion-sensitive OCT (DS-OCT), where we collect M-mode image ensembles, from which we derive depth- and temporally-resolved GNR diffusion rates. DS-OCT allows for real-time monitoring of changing GNR diffusion as a result of topically applied mucus-thinning agents, enabling monitoring of the dynamics of mucus hydration never before seen. Cultured human airway epithelial cells (Calu-3 cell) with a layer of endogenous mucus were doped with topically deposited GNRs (80x22nm), and subsequently treated with hypertonic saline (HS) or isotonic saline (IS). DS-OCT provided imaging of the mucus thinning response up to a depth of 600μm with 4.65μm resolution, over a total of 8 minutes in increments of ≥3 seconds. For both IS and HS conditions, DS-OCT captured changes in the pattern of mucus hydration over time. DS-OCT opens a new window into understanding mechanisms of mucus thinning during treatment, enabling real-time efficacy feedback needed to optimize and tailor treatments for individual patients.}, journal={OPTICAL COHERENCE TOMOGRAPHY AND COHERENCE DOMAIN OPTICAL METHODS IN BIOMEDICINE XX}, author={Blackmon, Richard L. and Kreda, Silvia M. and Sears, Patrick R. and Ostrowski, Lawrence E. and Hill, David B. and Chapman, Brian S. and Tracy, Joseph B. and Oldenburg, Amy L.}, year={2016} }
 @article{blackmon_sandhu_chapman_casbas-hernandez_tracy_troester_oldenburg_2016, title={Imaging Extracellular Matrix Remodeling In Vitro by Diffusion-Sensitive Optical Coherence Tomography}, volume={110}, ISSN={["1542-0086"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000374859600019&KeyUID=WOS:000374859600019}, DOI={10.1016/j.bpj.2016.03.014}, abstractNote={The mammary gland extracellular matrix (ECM) is comprised of biopolymers, primarily collagen I, that are created and maintained by stromal fibroblasts. ECM remodeling by fibroblasts results in changes in ECM fiber spacing (pores) that have been shown to play a critical role in the aggressiveness of breast cancer. However, minimally invasive methods to measure the spatial distribution of ECM pore areas within tissues and in vitro 3D culture models are currently lacking. We introduce diffusion-sensitive optical coherence tomography (DS-OCT) to image the nanoscale porosity of ECM by sensing weakly constrained diffusion of gold nanorods (GNRs). DS-OCT combines the principles of low-coherence interferometry and heterodyne dynamic light scattering. By collecting co- and cross-polarized light backscattered from GNRs within tissue culture, the ensemble-averaged translational self-diffusion rate, DT, of GNRs is resolved within ∼3 coherence volumes (10 × 5 μm, x × z). As GNRs are slowed by intermittent collisions with ECM fibers, DT is sensitive to ECM porosity on the size scale of their hydrodynamic diameter (∼46 nm). Here, we validate the utility of DS-OCT using pure collagen I gels and 3D mammary fibroblast cultures seeded in collagen/Matrigel, and associate differences in artificial ECM pore areas with gel concentration and cell seed density. Across all samples, DT was highly correlated with pore area obtained by scanning electron microscopy (R(2) = 0.968). We also demonstrate that DS-OCT can accurately map the spatial heterogeneity of layered samples. Importantly, DS-OCT of 3D mammary fibroblast cultures revealed the impact of fibroblast remodeling, where the spatial heterogeneity of matrix porosity was found to increase with cell density. This provides an unprecedented view into nanoscale changes in artificial ECM porosity over effective pore diameters ranging from ∼43 to 360 nm using a micron-scale optical imaging technique. In combination with the topical deposition of GNRs, the minimally invasive nature of DS-OCT makes this a promising technology for studying tissue remodeling processes.}, number={8}, journal={BIOPHYSICAL JOURNAL}, author={Blackmon, Richard L. and Sandhu, Rupninder and Chapman, Brian S. and Casbas-Hernandez, Patricia and Tracy, Joseph B. and Troester, Melissa A. and Oldenburg, Amy L.}, year={2016}, month={Apr}, pages={1858–1868} }