Publications by authors named "Cheolhee Ahn"

Article Synopsis
  • - This study introduces a new composite material made by integrating laser-induced graphene (LIG) onto a polylactic acid (PLA) substrate, resulting in a shape memory polymer composite (SMPC) that can respond to multiple stimuli and detect its own deformation.
  • - LIG was successfully transferred onto the PLA substrate using hot compression, showing good adhesion and optimal electrical properties, which enable temperature control through Joule heating when power is applied.
  • - The composite’s ability to react to infrared light and self-sense deformation via changes in electrical resistance provides a simple manufacturing method, paving the way for advanced materials that are both responsive and capable of real-time monitoring without the need for additional components.
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  • Dynamic covalent networks can effectively dissipate high mechanical energy through reversible bonds, but understanding their efficiency related to polymer mobility and bond exchange rates is still lacking.
  • This study investigates how to enhance energy dissipation in these networks by adjusting the side chain structures and bond exchange rates, using lipoic acid-derived polymers as a primary example.
  • Results show a strong link between energy dissipation and the polymers' glass transition temperature, and employing a catalyst to speed up disulfide exchanges boosts energy dissipation; additionally, the polymers display self-healing and recycling properties.
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This study investigated the sustainable toughening of polylactic acid (PLA) by incorporating ultrafine fully vulcanized powdered natural rubber graft-copolymerized with poly-styrene-co-acrylonitrile (UFPNR-SAN). We investigated the effect of the styrene-to-acrylonitrile ratio (ST:AN) used during the grafting process on the final UFPNR-SAN compatibility with PLA. The ST:AN ratio was systematically varied during the grafting reaction to prepare UFPNR-SAN with a range of different surface energies.

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  • This study investigated how loading titanium nitride (TiN) nanoparticles into a bio-based benzoxazine/epoxy copolymer affects the performance of the composite, particularly focusing on its shape memory properties under sunlight irradiation.
  • Researchers found that varying levels of TiN (from 1 to 7 wt%) improved the light absorbance, thermal stability, and physical properties (visco-elastic and tensile) of the composites, with an optimum performance observed at TiN-5(wt%).
  • The composite with the highest TiN loading (TiN-7(wt%)) demonstrated significant enhancements in shape memory performance, achieving a shape fixity ratio of 95% and a recovery time of 38 seconds, showcasing the
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  • - This text is a correction notice for a previously published article, identified by the DOI: 10.1039/D3NA01026K.
  • - The correction is likely to address errors or inaccuracies found in the original publication.
  • - Readers are encouraged to refer to the corrected version for accurate information and findings.
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  • Endovascular embolization is a minimally invasive method for treating blood vessel lesions, using liquid agents to block blood flow under X-ray guidance.
  • Histoacryl, a common liquid embolic agent, has limitations like poor X-ray visibility and strong adhesion to the delivery device, prompting the research into alternative agents.
  • The study developed and tested a new agent called 4-iodobutyl 2-cyanoacrylate (IBCA), which showed promising results in experiments with rabbits and swine, indicating its potential for clinical use.
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Copper-based nanomaterials have been employed as therapeutic agents for cancer therapy and diagnosis. Nevertheless, persistent challenges, such as cellular toxicity, non-uniform sizes, and low photothermal efficiency, often constrain their applications. In this study, we present Cu-loaded silica nanoparticles fabricated through the chelation of Cu ions by silanol groups.

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  • Laser-induced graphene (LIG) is usually made from polyimide, but its flexible nature limits its use in certain applications; polybenzoxazine is being investigated as an alternative substrate despite its brittleness and lower thermal stability.
  • The study aims to improve the properties of polybenzoxazine by combining it with polyimide, enhancing factors like toughness, char residue, and thermal stability, and further analyzing the resultant LIG's electrical resistivity and structural features.
  • The research yielded LIG with better electrical properties and structure compared to traditional polybenzoxazine, achieving impressive results with optimal laser settings, and validated a quadratic model to describe the production process effectively.
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In confined environments such as aircraft, an increase in mass impacts the overall system's performance, thus requiring sophisticated management. To verify whether the performance characteristics of fire extinguishing systems used in aircraft are satisfied, in this study was built a 1:1 scale test model. We examined the influence of the initial charge state and nozzles.

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Proteolysis-targeting chimeras (PROTACs) have recently been of great interest in cancer therapy. However, the bioavailability of PROTACs is considerably restricted due to their high hydrophobicity, poor cell permeability, and thereby low tumor targeting ability. Herein, esterase-cleavable maleimide linker (ECMal)-conjugated bromodomain 4 (BRD4)-degrading PROTAC (ECMal-PROTAC) is newly synthesized to exploit plasma albumin as an 'innate drug carrier' that can be accumulated in targeted tumor tissues.

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A prodrug is bioreversible medication that is specifically converted to the active drugs by enzymes overexpressed in the tumor microenvironment, which can considerably reduce the chemotherapy-induced side effects. However, prodrug strategies usually have low antitumor efficacy compared to free drugs by delayed drug release. This is because they need time to be activated by enzymatic cleavage and they also cannot be fully recovered to the active drugs.

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  • Albumin is a promising natural drug carrier that can enhance the effectiveness and targeting of anticancer treatments by improving their pharmacokinetics and enabling passive tumor targeting through the EPR effect.
  • *The most notable example is Abraxane, an FDA-approved formulation that uses human serum albumin to deliver the cancer drug paclitaxel, but many other albumin-based formulations have struggled with low delivery efficiency and potential toxicity.
  • *This review discusses various albumin-based drug delivery systems, their challenges, and recent developments aimed at improving their clinical translation and safety for better cancer treatment outcomes.
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One of the promising cancer treatment methods is photothermal therapy (PTT), which has achieved good therapeutic efficiency through nanoparticle-based photoabsorbers. Because of the various functions of nanoparticles, such as targeting properties, high light-to-heat conversion, and photostability, nanoparticle-mediated PTT successfully induces photothermal damage in tumor tissues with minimal side effects on surrounding healthy tissues. The therapeutic efficacy of PTT originates from cell membrane disruption, protein denaturation, and DNA damage by light-induced heat, but these biological impacts only influence localized tumor areas.

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  • The blood-brain barrier (BBB) complicates drug delivery and imaging in brain disorders, prompting interest in new methods like ultrasound-mediated nanoparticle delivery.
  • Focused ultrasound (FUS) can temporarily open the BBB, allowing for better delivery of therapeutic agents and enhancing photoacoustic brain imaging techniques, which have high resolution and penetration capability.
  • The combination of ultrasound and nanoparticles shows promise for improving both the diagnosis and treatment of brain-related conditions through effective visualization and targeted therapy.*
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Prodrugs are bioreversible medications that should undergo an enzymatic or chemical transformation in the tumor microenvironment to release active drugs, which improve cancer selectivity to reduce toxicities of anticancer drugs. However, such approaches have been challenged by poor therapeutic efficacy attributed to a short half-life and low tumor targeting. Herein, we propose cathepsin B-overexpressed tumor cell activatable albumin-binding doxorubicin prodrug, Al-ProD, that consists of a albumin-binding maleimide group, cathepsin B-cleavable peptide (FRRG), and doxorubicin.

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Photothermal therapy (PTT) is one of the most promising cancer treatment methods because hyperthermal effects and immunogenic cell death via PTT are destructive to cancer. However, PTT requires photoabsorbers that absorb near-infrared (NIR) light with deeper penetration depth in the body and effectively convert light into heat. Gold nanoparticles have various unique properties which are suitable for photoabsorbers, e.

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  • Transarterial chemoembolization (TACE) targets hepatocellular carcinoma by blocking blood supply to the tumor and enhancing anticancer drug delivery, using embolic agents such as drug-eluting beads (DEBs).
  • This study developed new size-controlled polymeric microspheres (PLGA MSs) that are radiopaque (visible on X-rays) and biodegradable, potentially overcoming limitations of existing DEBs.
  • The PLGA MSs effectively delivered anticancer drugs in animal tests, and their success was confirmed by imaging and observing kidney atrophy in the treated subjects, suggesting they could be a promising option for treating liver cancer.
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  • Co-delivery of microbubbles (MBs) with anticancer drugs can improve drug delivery and ultrasound imaging using the sonoporation effect, but challenges exist in drug loading and MB stability.
  • This study introduces a novel type of MB called MB-self-aggregate complexes (MB-SAs) that effectively encapsulate hydrophobic drugs without compromising MB stability.
  • The research demonstrated that GC@MBs (glycol chitosan self-aggregates attached to MBs) enhance cellular uptake and increase drug accumulation in tumors by 1.85 times with ultrasound, showing promise for improved cancer treatment and imaging.
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Injectable hydrogels have been studied as drug delivery systems because of their minimal invasiveness and sustained drug release properties. Pluronic F127, consisting of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers, exhibits thermo-responsive properties and hence is injectable due to its rapid sol-gel transition. Unmodified Pluronic F127-based hydrogels, however, have limited long-term stability and controllable release of drugs entrapped within them.

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  • Lymph node mapping is crucial in cancer immunotherapy as it helps evaluate immune responses, and new theragnostic glycol-chitosan-coated gold nanoparticles (GC-AuNPs) enhance lymph node visibility in ultrasound-guided photoacoustic imaging.
  • The engineered OVA-GC-AuNPs effectively deliver tumor antigens to macrophages in lymph nodes, showing strong endocytosis and resulting in robust photoacoustic signals.
  • After injecting GC-AuNPs in mice, imaging demonstrates increased accumulation over time in lymph nodes, revealing their potential for improved cancer immunotherapy by presenting tumor antigens to activate immune responses.
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  • * The study introduces a new method using laser desorption ionization mass spectrometry (LDI-MS) combined with tungsten disulfide nanosheets, which improves sensitivity and reproducibility for drug monitoring.
  • * This innovative approach enables high-throughput analysis of blood samples, successfully tested on 80 patient cases, showing promise to replace existing methods and improve drug management for organ transplant patients.
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Islet cell transplantation has been an effective method for the treatment of type 1 diabetes. The transplanted islets release insulin in response to changes in blood glucose levels. The clinical application of islet transplantation, however, has been hindered because of some critical problems including immune responses to grafted islets and side effects caused by overdosed immunosuppressive drugs.

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Utility of glycol-chitosan-coated gold nanoparticles (GC-AuNPs) as a photoacoustic contrast agent for cancer cell imaging was demonstrated. Through the synergistic effect of glycol chitosan and gold nanoparticles, GC-AuNPs showed cellular uptake in breast cancer cells and resulted in strong photoacoustic signals in tissue-mimicking cell phantoms. The performance of GC-AuNPs as contrast agents was established with photoacoustic imaging and confirmed with dark-field microscopy.

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This study aims to develop a novel surface modification technology to prolong the survival time of pancreatic islets in a xenogenic transplantation model, using 3,4-dihydroxyphenethylamine (DOPA) conjugated poly(lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) nanoparticles (DOPA-NPs) carrying immunosuppressant FK506 (FK506/DOPA-NPs). The functionalized DOPA-NPs formed a versatile coating layer for antigen camouflage without interfering the viability and functionality of islets. The coating layer effectively preserved the morphology and viability of islets in a co-culture condition with xenogenic lymphocytes for 7 days.

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  • Thrombosis is a significant factor in cardiovascular diseases, leading to oxygen deprivation and tissue damage due to thrombus formation.
  • Researchers developed a new imaging tool using thrombin-activatable fluorescent peptide (TAP) and silica-coated gold nanoparticles (TAP-SiO@AuNPs) for enhanced thrombus detection via dual near-infrared fluorescence (NIRF) and micro-computed tomography (micro-CT).
  • In in vitro tests, the TAP-SiO@AuNPs showed a strong increase in fluorescence when thrombin was present, allowing for clear distinction between thrombotic lesions and surrounding tissues in a mouse model, highlighting their potential for clinical use in diagnosing and treating thrombosis.
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