Browsing by Author "Zhao, Chao"
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Item Applications of capillary action in drug delivery(Cell Press, 2021) Li, Xiaosi; Zhao, Yue; Zhao, Chao; University of Alabama Tuscaloosa; Northwestern Polytechnical UniversityContrary to the fact that capillary action is ubiquitous in our daily lives, its role in drug delivery has not attracted attention. Therefore, its application in medicine and disease treatment has not been actively developed. This perspective begins by reviewing the principles, advantages, and limitations of the three existing drug delivery strategies: non-covalent interaction, cavity loading, and covalent conjugation. Then, we discussed the principle of capillary action in drug delivery and the influencing factors that determine its performance. To illustrate the advantages of capillary action over existing drug delivery strategies and how the capillary action could potentially address the shortcomings of the existing drug delivery strategies, we described five examples of using capillary action to design drug delivery platforms for disease treatment: marker pen for topical and transdermal drug delivery, microneedle patch with a sponge container for pulsatile drug delivery, core- shell scaffold for sustained release of growth factors, oral bolus for insulin delivery to the esophagus, and semi-hollow floating ball for intravesical and gastroprotective drug delivery. Each of the five drug delivery platforms exhibits certain unique functions that existing drug delivery technologies cannot easily achieve, hence expected to solve specific practical medical problems that are not satisfactorily resolved. As people pay more attention to capillary action and develop more drug delivery platforms, more unique functions and characteristics of capillary action in drug delivery will be explored. Thus, capillary action could become an important choice for drug delivery systems to improve therapeutic drug efficacy, treat diseases, and improve human health.Item A Biomimetic Hydrogel Based Model to Investigate the Influence of Microenvironmental Biochemical Cues on Brain Metastatic Breast Cancer Cell Behaviors(University of Alabama Libraries, 2024) Goodarzi, Kasra; Rao, ShreyasA majority of breast cancer related deaths occur due to the metastasis of breast cancer cells to distant organs. Of all the organ sites, metastasis to the brain is very aggressive and has been associated with a poor prognosis and a survival time of less than one year. Both cellular and non-cellular components of the tumor microenvironment (TME) play an important role in disease progression including regulation of dormancy versus proliferation as well as invasion. As a key component of the TME, the extracellular matrix (ECM) provides structural support, as well as biomechanical and biochemical cues that influence disease progression. However, in the context of breast cancer brain metastasis (BCBM), the role of biochemical cues in regulating dormancy versus proliferation as well as invasion in cancer cells is not well understood. This, in turn, hinders progress in developing effective therapeutic approaches for BCBM. This dissertation focuses on elucidating how ECM biochemical cues influence the dormant versus proliferative state as well as invasiveness of BCBM cells. Specifically, a hyaluronic acid (HA) hydrogel-based platform that mimics key aspects of the brain microenvironment was employed to provide a physiologically relevant environment for the cancer cells in vitro. HA hydrogels were modified via functionalization with ECM-derived proteins or peptides, including laminin protein, laminin-derived peptides IKVAV and YIGSR, as well as fibronectin-derived RGD peptide, to study the impact of the microenvironmental biochemical cues on modulating the dormant versus proliferative state of BCBM cells. Additionally, structurally decoupled HA hydrogels were utilized as a biomimetic 3D culture platform to model matrix metalloproteinase (MMP)-mediated invasion in BCBM spheroids by incorporating varying degradable sites. Taken together, this dissertation aimed to provide new insights into the regulation of dormancy versus proliferation in BCBM cells as well as invasion mediated by biochemical cues.Item Developing 3D Engineered in Vitro Models to Study the Impact of Brain Microenvironment Derived Cues and Chemotherapy Drugs on Dormancy in Brain Metastatic Breast Cancer(University of Alabama Libraries, 2023) Kondapaneni, Raghu Vamsi; Rao, Shreyas SBreast cancer cells are known to disseminate to distant organs (brain, liver, lungs, bone, and lymphnodes) to develop secondary (metastatic) tumors. Upon arriving in the secondary organ, disseminated tumor cells (DTCs) exhibit dormancy to evade cell death and gain therapeutic resistance via tumor microenvironment-derived biomechanical, cellular and/or bio-chemical cues. Metastatic breast cancers are considered to be incurable with a dismal 5-year survival rate of only 27%. Among breast cancer metastasis, breast cancer brain metastasis (BCBM) is very aggressive with a median survival rate of 15 months. A mechanistic understanding of tumor cell-brain microenvironment interactions involved in attaining a dormant state in BCBM cells is crucial inidentifying new therapeutic targets for BCBM. This dissertation focuses on studying the impact of extracellular matrix derived cues, cellular cues and chemotherapy drugs on BCBM dormancy. Specifically, hyaluronic acid (HA) hydrogels with matrix stiffness comparable to both native brain and brain metastatic niche were utilized to study the impact of biomechanical cues on tumor dormancy in BCBM cell clusters (spheroids). The impact of spheroid size on tumor dormancy was also studied. In addition, this hydrogel system was employed to study regulation of tumor mass dormancy in BCBM spheroids. Further, impact of a chemotherapeutic drug (Paclitaxel) on BCBM dormancy was studied. Finally, HA hydrogel based dormancy model was utilized to study the impact of cellular cues on theregulation of BCBM dormancy, by co-culturing dormant BCBM cells with astrocytes. Taken together, the development of such models is poised to provide key scientific insights into the mechanisms involved in BCBM dormancy.Item Development and Applications of Opioids Alternatives for Pain Management(University of Alabama Libraries, 2024) Li, Qi; Zhao, ChaoThis dissertation explores alternative pain management strategies to opioids, focusing on tetrodotoxin (TTX) and capsaicin as novel anesthetics. Acute post-surgical pain typically lasts 5-7 days, while long-term pain management can span up to 12 weeks. Opioids are commonly used but are linked to serious side effects, including addiction, nausea, cognitive impairment, and fatal overdoses. TTX is a site-1 sodium channel blocker, nearly 1000 times more potent than conventional amino-amide and amino-ester local anesthetics, and it lacks the myotoxicity and nerve toxicity often associated with these anesthetics. However, its systemic distribution can cause fatal diaphragm paralysis. To limit this, drug delivery systems were developed to refine the release kinetics of TTX. Initially, a hydration-induced void-containing hydrogel system was created to encapsulate TTX physically. Following a simple hydration process between the polymer and the TTX solution, TTX was successfully encapsulated in voids shielded by densely packed polymer, achieving 100% encapsulation efficiency. These injectable hydrogels can be stored for several months without compromising drug encapsulation and release properties. A single injection of the hydrogel/TTX formulation produced a sciatic nerve block lasting up to 10 hours.Despite progress, the duration of nerve blockade remains insufficient for clinical needs. The physical encapsulation method limits TTX dosage due to unstable release kinetics. Therefore, polymer-TTX conjugates were developed by chemically conjugating TTX to the polymer backbone and releasing it through ester bond hydrolysis. This increased the TTX dosage nearly 40-fold, prolonging the nerve blockade to more than three days.Finally, a galacturonic acid-capsaicin prodrug was developed. Capsaicin, the active component of chili peppers, selectively targets the transient receptor potential vanilloid-1 (TRPV1) receptor to block nociceptive signaling without affecting motor nerves. The prodrug utilized facilitated transport by glucose transporters across the perineurium, eliminating the side effects typically caused by capsaicin, such as burning pain, seizures, and respiratory depression. A single injection at the sciatic nerves of rats resulted in nociceptive-selective nerve blockade lasting 10 days with minimal tissue toxicity or side effects.This research aims to address the limitations of traditional pain management methods and pave the way for safer, more effective pain management solutions that could benefit patients suffering from postoperative pain.Item Editorial: Bioactive bone regenerative materials and bionic prosthesis interfaces(Frontiers, 2022) Liu, He; Tian, Yuhang; Zhao, Chao; Ding, Jianxun; Jilin University; University of Alabama Tuscaloosa; Chinese Academy of Sciences; Changchun Institute of Applied Chemistry, CASItem Editorial: Bioengineering and translational research for bone and joint diseases(Frontiers, 2022) Dou, Yun; Fang, Yin; Zhao, Chao; Fu, Weili; Jiang, Dong; Peking University; Nanyang Technological University & National Institute of Education (NIE) Singapore; Nanyang Technological University; University of Alabama Tuscaloosa; Sichuan UniversityItem Editorial: Nanotechnology in Cardiovascular Regenerative Medicine(Frontiers Media, 2020) Cui, Wenguo; Wang, Aijun; Zhao, Chao; Zhu, Wuqiang; Shanghai Jiao Tong University; University of California System; University of California Davis; University of Alabama Tuscaloosa; Mayo Clinic; Mayo Clinic PhoenixItem Harnessing CO₂ and in-situ nanoparticles to strengthen and decarbonize Portland cement-based concrete(University of Alabama Libraries, 2025) Wang, Xiaodong; Wang, JialaiThe production of ordinary Portland cement (OPC) is responsible for nearly 8% of global anthropogenic CO₂ emissions. A promising strategy to address this challenge is to improve concrete performance, thereby reducing the amount of cement or concrete required in construction. This dissertation presents two innovative methods that significantly enhance the compressive strength of concrete, offering a practical pathway toward more efficient and sustainable cement-based construction. The first approach--biomolecule-regulated slurry carbonation (BioCarb)--utilizes concrete as a CO₂ sink through a mineralization process in which CO₂ reacts with calcium-rich cement phases to form calcium carbonate (CaCO₃), thereby enabling permanent CO₂ storage. Unlike existing carbonation methods, the BioCarb process introduces CO₂ into a lightly pre-hydrated cement slurry prior to mixing, in the presence of a multifunctional biomolecule that regulates the carbonation reaction. This biomolecule (i) chelates calcium ions to accelerate carbonation, (ii) controls the nucleation, morphology, and crystallinity of CaCO₃, (iii) promotes the formation of reactive silica gel, and (iv) disperses the resulting CaCO₃ nanoparticles. As a result, CO₂ uptake reaches levels at least 25 times higher than existing, and the 28-day compressive strength of the produced cement mortar is enhanced by more than 20%.The second approach enables the in-situ formation of silica nanoparticles using low-cost, environmentally friendly precursors. This strategy overcomes two major challenges that have hindered the practical use of nanoparticles in concrete: high cost and poor dispersion. The in-situ synthesized silica acts as both a nucleation site and a reactive pozzolan, resulting in a 10-15% increase in 28-day strength while allowing for a 10% reduction in clinker content, with strength retention of 90-95% compared to the control. Mercury intrusion porosimetry revealed a 35% reduction in critical pore diameter. Together, these two approaches offer a scalable and cost-effective solution for reducing cement consumption and decarbonizing concrete production. Both methods rely on inexpensive, widely available chemicals and require only minor modifications to current workflows--such as sealed pre-mixers and access to standard CO₂ or silicate supplies. Their compatibility with existing ready-mix infrastructure makes them well-positioned for rapid industrial adoption, paving the way for significant reductions in greenhouse gas emissions across the built environment.Item Innovative technologies and materials for treatments of hepatobiliary and pancreatic diseases(Frontiers, 2023) Li, Di; Zhao, Chao; Xu, Weiguo; Liu, Yahui; Jilin University; Chinese Academy of Sciences; Changchun Institute of Applied Chemistry, CAS; University of Alabama TuscaloosaItem Low-Cost Cenosphere Microencapsulation Technology for Phase Change Materials: a Sustainable Approach to Improving the Thermal and Mechanical Performance of Construction Materials for Operational Carbon Reduction(University of Alabama Libraries, 2024) Ismail, Abdulmalik Bamidele; Wang, JialaiOperational carbon emissions from heating, ventilating, cooling, and air conditioning in buildings account for 28% of global greenhouse gas emissions. These emissions can be reduced by improving the energy efficiency of buildings. One way to do this involves incorporating phase change materials (PCM) into cementitious composites to optimize thermal energy storage and regulation. The challenge lies in preventing PCM leakage and maintaining heat transfer efficiency, as existing PCM microcapsules (MPCMs) are costly and compromise the strength of cementitious composites due to their inherent low mechanical properties.To address these limitations, a novel microencapsulation technique was proposed. This involved utilizing cenosphere, a low-cost, high-strength, hollow microsphere derived from coal-burning power plants, as the protective shell for the new MPCM. The PCM in liquid phase can be loaded into the cenosphere after removing a thin silica film through chemical etching, resulting in a cenosphere-PCM microcapsule (CPCM). To seal perforations induced during production, three novel and cost-effective coatings (silica, ethyl cellulose, and bio-inspired silica) were applied to the CPCM.An extensive experimental plan was executed to optimize the etching process, characterize the coated CPCMs, evaluate their energy density, and assess the impact of each coating on the strengths of resulting cementitious composites. Additionally, the thermal performance of the cementitious composites with incorporated microcapsules was thoroughly examined. The results showed that the concentration of the etching agent significantly affects the etching duration, morphology, and size of the perforations on the cenosphere. Furthermore, the results showed that all the microcapsules exhibited superior thermal and mechanical properties compared to existing microcapsules due to their high crushing strength. Generally, the coatings improved the thermal stability of the CPCM accompanied by some reduction in latent heat. This reduction is largely attributed to the thickness of the coating layer. Bio-inspired silica-coated CPCM exhibited the best thermal performance, delayed the thermal decomposition of the PCM by about 50°C, and showed the best thermal performance profile. Cenosphere provides huge potential for the integration of PCM into building materials for thermal energy storage while still maintaining the structural integrity of the cementitious composites.Item Low-cost, ubiquitous biomolecule as next generation, sustainable admixture to enhance the performance of ordinary portland cement-based concretes(University of Alabama Libraries, 2021) Fang, Yi; Wang, Jialai; University of Alabama TuscaloosaThe production of ordinary Portland cement (OPC) is highly energy-intensive and responsible for approximately 6% of anthropogenic greenhouse gas emissions. To reduce the carbon footprint of OPC based concrete, this research proposes to use a low-cost, ubiquitous, naturally occurring compound, tannic acid (TA) as a small-dose additive to significantly enhance the strength of OPC based concrete.This study is inspired by biosystems’ protein-based materials, which generally exhibit superior strength and toughness owing to their hierarchical structures via hydrogen-bonding assembly. With abundant reactive terminal phenolic hydroxyl groups, TA has an ability to complex or cross-link macromolecules sites through multiple interactions. Thus, TA can be used to complex or cross-link hydration products of cement at multi-binding sites so that the strength and durability of concrete can be significantly improved. A comprehensive research plan has been carried out to evaluate the potential of TA on performance enhancement of OPC-based concrete, understand how TA modifies the hydration of cement, mitigate the retardation of TA on cement’s hydration, and evaluate application potentials in concretes with SCMs. Experimental studies show that TA can strongly retard the hydration of cement and alite due to its ability to bind to various particles and chelate with calcium ions, causing less calcium hydroxide produced by the hydration. The strong interaction between the TA and hydration products leads to morphology change of the hydration products and generates nanoparticles at early age. Furthermore, addition of TA can significantly densify the nanostructure of cement pastes. Particularly, capillary pores smaller than 70nm are drastically reduced by TA. This finding is not only explaining why TA can enhance the micromechanical properties of concrete, but also opening a new approach to tune the nanoscale pores in concrete. Besides, a pre-hydration method is proposed and verified to mitigate the retarding effect of TA for widely adopted in practical application. Significant strength improvement at late age can be achieved by pre-hydration with TA without losing of strength at early age. TA is also successfully used in mortars with silica fume to achieve over 30% strength improvement, suggesting its huge potential to reduce the carbon footprint of concrete.Item A Novel Magnetic Drug Screening Nanoplatform for the Identification of Drug Leads from Complex Matrices(University of Alabama Libraries, 2024) Mansur, Shomit; Bao, YupingTransmembrane proteins have reached a significant value as drug targets with more than half of modern drugs targeting them. However, the identification of new drug leads specifically targeting transmembrane receptors has been complicated as they need to be functionalized by boundary lipids. Current drug discovery tools such as high throughput screening assays require the isolation of individual compounds and are not suitable for screening complex matrices. Therefore, it is highly desirable to design a drug discovery tool that can screen identified compounds from complex matrices by immobilizing the transmembrane protein target on a solid surface. Here, we establish a screening method to identify specific transmembrane protein binders from complex matrices. Using voltage-gated sodium ion channels as a model system, we report the immobilization of this protein on magnetic superparticles of controlled size and surface chemistry, where the functional VGSCs directly fish out specific binders from a mixture and superparticles enable rapid isolation through magnetic separation. This dissertation aims to elucidate the efficacy of our proposed drug screening system by utilizing different complex matrices on more than one transmembrane protein target. We first successfully synthesized and characterized superparamagnetic iron oxide superparticles of controlled size, shape, and surface chemistry. Then we successfully immobilized the transmembrane protein target around a negative surface charge magnetic superparticles, enabling a complete membrane encapsulation, as characterized by transmission electron microscopy and dynamic light scattering. We used this membrane encapsulated-superparticles as a screening tool to effectively fish out specific binders from complex mixtures. The specific binders were analyzed by ultra-high-performance liquid chromatography followed by quadrupole time-of-flight mass spectrometry. The identified binders were then evaluated to determine their modulatory effect on protein targets in vitro. Finally, we emphasized on a targeted delivery system for the identified binders and explored the potential of extracellular vesicles (EVs) as biomimetic nanocarriers. EVs showed high potential as vehicles to deliver drugs to a subcellular region of their origin cell, where drugs can specifically bind to their target and modulate their activity. However, further studies need to be performed to determine the effect of these parental cell-derived EVs on their cells of origin. Our future studies will delve deeper into understanding the subcellular effect of EVs as drug vehicles and their potential to cross the blood-brain barrier without adverse effects. Subsequent studies will also emphasize on re-evaluating the drug screening nanoplatform to elucidate the interfacial chemistry effects of the superparticle surface with the membrane and their potential in binding selectivity.Item Plasma Assisted Catalytic Dry Reforming of Methane Over CEO? Supported Ruthenium Nanocatalysts(University of Alabama Libraries, 2022) Ahasan, Md Robayet; Wang, RuigangThermodynamic barriers of dry reforming of methane (DRM) determine that the reaction requires high operating temperature (>750°C), and its side reactions lead to carbon deposition and catalyst deactivation. Under plasma conditions, high energy electrons and excited radicals can collide with bulk gas molecules, causing bond breaking of molecules and formation of highly reactive species (i.e., vibrationally and electronically excited ions and free radicals) at temperatures at which such species are thermally inaccessible. Dielectric barrier discharge (DBD) reactor has been mostly used as a plasma source in catalytic DRM systems due to its simple configuration with low cost as well as easy control of several reactor parameters. This project takes the advantages of non-equilibrium plasma catalysis and surface engineered catalyst synthesis techniques, to convert two major greenhouse gases (CH4 and CO2) to syngas and/or value added chemicals below 550 °C in a DBD reactor, which could mitigate the nanocatalyst deactivation due to aging and carbon deposition at elevated temperature. In this thesis, 1 wt% Ru nanocatalysts supported on irreducible SiO2 and reducible CeO2 with two different morphologies (CeO2 nanorods: CeO2-NR and CeO2 nanocubes: CeO2-NC), exposing facets with {110}/{100}/{1 1 1} , respectively, were prepared to investigate the non-thermal plasma influence as well as the support shape effect on the DRM reaction rate and selectivity. All the prepared nanocatalysts were characterized by XRD, BET, Raman spectroscopy, H2-TPR, CO2-TPD, XPS, HRTEM, and EDS. From quadrupole mass spectrometer (QMS) data, it is concluded that introducing non-thermal plasma significantly promotes simultaneous conversion of CH4 and CO2 at lower temperatures than under thermal only conditions, due to highly energetic electrons, ions, and radicals in the plasma region. The molar concentrations of CO and H2 products were 16% and 9% respectively for plasma assisted thermo-catalytic DRM at 350°C while it was zero (0%) conversion for thermo-catalytic DRM. The exposed crystal planes of oxide support also play a crucial role in the distribution and valence state of Ru species and conversion rate/selectivity of CH4 and CO2. For instance, at 450 °C, 1 wt% Ru/CeO2 NR sample showed higher catalytic activity with 51% CH4 and 37% CO2 conversion compared to 1 wt% Ru/CeO2 NC with 40% CH4 and 30% CO2 conversion. This clearly indicates the shape effect of CeO2 support. This enhanced DRM activity is ascribed to the specific exposed surface facets of CeO2 NR that provide higher amounts of oxygen vacancy and surface defects than CeO2 NC.Item Recent Development of pH-Responsive Polymers for Cancer Nanomedicine(MDPI, 2019) Tang, Houliang; Zhao, Weilong; Yu, Jinming; Li, Yang; Zhao, Chao; Southern Methodist University; Merck & Company; University of Alabama Tuscaloosa; Harvard University; Harvard Medical School; Boston Children's HospitalCancer remains a leading cause of death worldwide with more than 10 million new cases every year. Tumor-targeted nanomedicines have shown substantial improvements of the therapeutic index of anticancer agents, addressing the deficiencies of conventional chemotherapy, and have had a tremendous growth over past several decades. Due to the pathophysiological characteristics that almost all tumor tissues have lower pH in comparison to normal healthy tissues, among various tumor-targeted nanomaterials, pH-responsive polymeric materials have been one of the most prevalent approaches for cancer diagnosis and treatment. In this review, we summarized the types of pH-responsive polymers, describing their chemical structures and pH-response mechanisms; we illustrated the structure-property relationships of pH-responsive polymers and introduced the approaches to regulating their pH-responsive behaviors; we also highlighted the most representative applications of pH-responsive polymers in cancer imaging and therapy. This review article aims to provide general guidelines for the rational design of more effective pH-responsive nanomaterials for cancer diagnosis and treatment.Item Strategies to Obtain Encapsulation and Controlled Release of Small Hydrophilic Molecules(Frontiers, 2020) Li, Qi; Li, Xiaosi; Zhao, Chao; University of Alabama TuscaloosaThe therapeutic effect of small hydrophilic molecules is limited by the rapid clearance from the systemic circulation or a local site of administration. The unsuitable pharmacokinetics and biodistribution can be improved by encapsulating them in drug delivery systems. However, the high-water solubility, very hydrophilic nature, and low molecular weight make it difficult to encapsulate small hydrophilic molecules in many drug delivery systems. In this mini-review, we highlight three strategies to efficiently encapsulate small hydrophilic molecules and achieve controlled release: physical encapsulation in micro/nanocapsules, physical adsorption via electronic interactions, and covalent conjugation. The principles, advantages, and disadvantages of each strategy are discussed. This review paper could be a guide for scientists, engineers, and medical doctors who want to improve the therapeutic efficacy of small hydrophilic drugs.Item Synthesis and characterization of fly ash based self-dispersing, self-sensing geopolymer(University of Alabama Libraries, 2020-12) Pan, Wei; Wang, Jialai; University of Alabama TuscaloosaExtensive studies have been carried out to use carbon nanotubes (CNTs) to reinforce cementitious materials because of the extraordinary strength of CNTs. More importantly, new functions such as self-sensing ability can be introduced to the materials due to the excellent electrical conductivity of CNTs. However, the application of CNTs in reinforcing materials is hampered by three major challenges: proper dispersion of the nanoscale additives, scale-up of laboratory results and implementation on larger scale, and a lowering of the cost benefit ratio. It is not easy to disperse CNTs into cementitious materials. Aiming to address all these three challenges simultaneously, this study proposes to produce CNTs reinforced cementitious materials through directly growing CNTs on fly ash particles using a novel Poptube method. Unlike any other exiting methods, Poptube method uses microwave irradiation as heating source, and a single chemical (e.g., ferrocene) to provide both the carbon source and the catalyst for CNTs’ growth. Compared with existing methods, the Poptube method is much more cost-effective and can be easily scaled-up for mass production. CNT reinforced geopolymer can be produced by mixing these CNTs grown fly ash particles with other ingredients. In this way, the time-consuming and difficult task of dispersion of CNTs is eliminated since CNTs are self-dispersed into the matrix by the fly ash particles on which CNTs were grown. To evaluate the effect of growing CNTs on the reactivity of fly ash particles, a series of tests were carried out, including dissolution testing, electric conductivity testing, and imaging with scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM). Results show that growing CNTs on the surface of fly ash does not reduce the reactivity of the fly ash because of the seeding effect provided by the CNTs. The composite effect induced by the CNTs was confirmed by Raman Spectrometer, which shows that the D-band of the CNTs varies with the applied thermal stress, suggesting effectively stress transfer from the geopolymer matrix to CNTs. This finding suggests that stress in CNTs reinforced geopolymer can be sensed by a Roman Spectrometer in a non-contact fashion. The self-sensing function of the nanocomposite mortar is evaluated using a four-electrode-DC method. At early age, geopolymer mortar is piezoresistive because of its high electric conductivity. However, DC induced polarization effect is very serious at this age. This polarization effect reduces with reaction time and becomes negligible at 35d. Similar piezoresitivity was achieved by the geopolymeric nanocomposite produced by using fly ash grown with CNTs using Poptube method, which is three orders magnitude more sensitive than the geopolymer one without any CNTs.Item Zero-Order Controlled Release of Water-Soluble Drugs Using a Marker Pen Platform(American Chemical Society, 2021) Li, Xiaosi; Li, Qi; Zhao, Chao; University of Alabama TuscaloosaZero-order drug release that releases drugs at a constant rate is beneficial to prolong the therapeutic effect and avoid the side effects of drugs. However, due to the weak interaction between the drug and the carrier, it is particularly challenging to achieve zero-order release of water-soluble drugs. Inspired by the marker pen, which stores the water-based ink in the sponge core and releases a constant amount of ink from the tip for writing, we explore the marker pen as a drug delivery platform to achieve zero-order release of water-soluble drugs. Through the capillary interaction between the material and water, the pen core can absorb the aqueous drug solution to encapsulate and store the water-soluble drug model sodium fluorescein (SF) and can release the encapsulated SF by moving the pen tip across the surface. The results show that the marker pen can release a constant amount of SF at the nanogram level per unit length of the line drawn with the pen, and the cumulative SF release amount has a linear relationship with the length of the line. In addition, the amount of released SF is linear with respect to the SF concentration in the aqueous solution. Moreover, the SF-filled marker pen has excellent long-term stability as evidenced by that the amount of SF released from the pen remains constant within two weeks after filling.