Chia-Hua Lin

Photothermal Therapeutic Response of Cancer Cells to Aptamer–Gold Nanoparticle-Hybridized Graphene Oxide under NIR Illumination

The objective of this study was to synthesize a nanocomposite, aptamer-gold nanoparticle-hybridized graphene oxide (Apt-AuNP-GO), to facilitate targeted treatment of tumor cells by near-infrared (NIR) light-activatable photothermal therapy. We also investigated whether Apt-AuNP-GO with NIR illumination modulates heat shock proteins (HSPs) expression leading to therapeutic response in human breast cancer cells. These findings can provide strategies for improving the photothermal therapy efficacy of cancer. The self-assembled Apt-AuNP-GO nanocomposite could selectively target MUC1-positive human breast cancer cells (MCF-7) due to the specific interaction between the MUC1-binding-aptamer and the MUC1 (type I transmembrane mucin glycoprotein) on cell membrane. In addition, Apt-AuNP-GO has a high light-to-heat conversion capability for photoabsorption of NIR light, and it is able to exert therapeutic effects on MCF-7 cells at an ultralow concentration without inducing adverse effects in healthy cells. The Apt-AuNP-GO nanocomposites combine the advantages of GOs, AuNPs, and Apts, possess specific targeting capability, excellent biocompatibility, and tumor cell destruction ability, suggesting great potential for application in the photothermal therapy of breast cancer. Under NIR illumination, Apt-AuNP-GO induced transient increase in HSP70 expression, which decreased thereafter. This phenomenon may cause irreversible damage to Apt-AuNP-GO-treated MCF-7 cell under NIR illumination. We also demonstrated that the combination therapy of heat and HSP70 inhibitor could synergistically generate marked tumoricidal effects against breast cancer. These results suggest that the degree and duration of HSP70 protein expression are correlated with therapeutic effects against breast cancer for Apt-AuNP-GO-assisted photothermal therapy. We believe that such a nanocomposite can be readily extended to the construction of HSP70 inhibitors-loaded Apt-AuNP-GO, which could deliver both heat and HSP70 inhibitors to tumorigenic regions for the chemo-photothermal therapy.

One-step synthesis of biofunctional carbon quantum dots for bacterial labeling

In this study, we used a simple one-step dry heating method to synthesize mannose-modified fluorescent carbon quantum dots (Man-CQDs) from solid ammonium citrate and mannose, and successfully applied for labeling Escherichia coli. The highly soluble Man-CQDs had an average particle diameter of 3.1±1.2 nm and exhibited a quantum yield of 9.8% at excitation and emission wavelengths of 365 and 450 nm, respectively. The fluorescent Man-CQDs could selectively bind to the FimH lectin unit in the flagella of the wild-type 1 E. coli K12 strain. We optimized the labeling efficiency of the Man-CQDs by controlling the ratio of ammonium citrate to mannose during their synthesis. The specific binding of the mannose units to E. coli allowed quantitative detection of the bacteria at levels down to 450 colony forming units mL(-1) in lab samples, and facilitate the application of the Man-CQDs for bacterial analyses of real samples (tap water, apple juice, human urine). The synthesis of our Man-CQDs, their labeling, and their use in the detection of bacteria were all simple, inexpensive and efficient processes.

Synthesis of Self‐Assembled Spermidine‐Carbon Quantum Dots Effective against Multidrug‐Resistant Bacteria

This study reports a two-step method to synthesize spermidine-capped fluorescent carbon quantum dots (Spd-CQDs) and their potential application as an antibacterial agent. Fluorescent carbon quantum dots (CQDs) are synthesized by pyrolysis of ammonium citrate in the solid state and then modified with spermidine by a simple heating treatment without a coupling agent. Spermidine, a naturally occurring polyamine, binds with DNA, lipids, and proteins involved in many important processes within organisms such as DNA stability, and cell growth, proliferation, and death. The antimicrobial activity of the as-synthesized Spd-CQDs (size ≈4.6 nm) has been tested against non-multidrug-resistant E. coli, S. aureus, B. subtilis, and P. aeruginosa bacteria and also multidrug-resistant bacteria, methicillin-resistant S. aureus (MRSA). The minimal inhibitory concentration value of Spd-CQDs is much lower (>25 000-fold) than that of spermidine, indicating their promising antibacterial characteristics. The mechanism of antibacterial activity is investigated, and the results indicate that Spd-CQDs cause significant damage to the bacterial membrane. In vitro cytotoxicity and hemolysis analyses reveal the high biocompatibility of Spd-CQDs. To demonstrate its practical application, in vitro MRSA-infected wound healing studies in rats have been conducted, which show faster healing, better epithelialization, and formation of collagen fibers when Spd-CQDs are used as a dressing material.

Polycyclic aromatic hydrocarbons are associated with increased risk of chronic obstructive pulmonary disease during haze events in China

Although exposure to particulate matter with a diameter of <2.5μm (PM2.5) is associated with chronic obstructive pulmonary disease (COPD), the major components of PM2.5 in COPD pathogenesis are controversial. Here we employed the human lung epithelial cell line BEAS-2B to elucidate the association between COPD and the organic and water-soluble components of PM2.5. We found that the PM2.5 organic extract was a potential major risk factor for pulmonary epithelial barrier dysfunction through the depletion of proteins from the zonula occludens. This extract induced severe oxidative stress that increased DNA damage and the production of proinflammatory cytokines by BEAS-2B cells as well as decreased α1-antitrypsin expression, suggesting a mechanism that increases the risk of COPD. These effects were mainly mediated by polycyclic aromatic hydrocarbons (PAHs) through the aryl hydrocarbon receptor pathway. PAHs with high benzo(a)pyrene (BaP)-equivalent concentrations, but not major PAH components, have an increased risk of causing COPD, suggesting that BaP-equivalent concentrations represent a PM2.5-induced COPD risk metric, which may contribute to provide a rationale for the remediation of air pollution.

Improved Anticancer Photothermal Therapy Using the Bystander Effect Enhanced by Antiarrhythmic Peptide Conjugated Dopamine-Modified Reduced Graphene Oxide Nanocomposite

&NA; Despite tremendous efforts toward developing novel near‐infrared (NIR)‐absorbing nanomaterials, improvement in therapeutic efficiency remains a formidable challenge in photothermal cancer therapy. This study aims to synthesize a specific peptide conjugated polydopamine‐modified reduced graphene oxide (pDA/rGO) nanocomposite that promotes the bystander effect to facilitate cancer treatment using NIR‐activated photothermal therapy. To prepare a nanoplatform capable of promoting the bystander effect in cancer cells, we immobilized antiarrhythmic peptide 10 (AAP10) on the surface of dopamine‐modified rGO (AAP10‐pDA/rGO). Our AAP10‐pDA/rGO could promote the bystander effect by increasing the expression of connexin 43 protein in MCF‐7 breast‐cancer cells. Because of its tremendous ability to absorb NIR absorption, AAP10‐pDA/rGO offers a high photothermal effect under NIR irradiation. This leads to a massive death of MCF‐7 cells via the bystander effect. Using tumor‐bearing mice as the model, it is found that NIR radiation effectively ablates breast tumor in the presence of AAP10‐pDA/rGO and inhibits tumor growth by ≈100%. Therefore, this research integrates the bystander and photothermal effects into a single nanoplatform in order to facilitate an efficient photothermal therapy. Furthermore, our AAP10‐pDA/rGO, which exhibits both hyperthermia and the bystander effect, can prevent breast‐cancer recurrence and, therefore, has great potential for future clinical and research applications. &NA; In vitro and in vivo models are used to explore the therapeutic effect in human cancer cells exposed to NIR‐irradiated antiarrhythmic peptide 10 on the surface of dopamine‐modified reduced graphene oxide (AAP10‐pDA/rGO). The AAP10‐pDA/rGO nanoplatform, which exhibits both hyperthermia and the bystander effect, can facilitate the photothermal cancer treatment and prevent cancer recurrence. The findings of this study offer a better understanding of the design of graphene‐based nanocomposites for cancer photothermal therapy. Figure. No caption available.

Nano Zerovalent Iron Particles Induce Pulmonary and Cardiovascular Toxicity in an in Vitro Human Co-culture Model

Abstract Despite promising environmental applications for nano zerovalent iron (nZVI), concerns remain about the potential accumulation and toxic effects of nZVI particles. Here, we use an alveolar-capillary co-culture model to investigate a possible link between low-level epithelial exposure to nZVI and pulmonary and cardiovascular toxicity. While nZVI was unable to pass through the epithelial barrier into the endothelium, nZVI exposure did cause oxidative and inflammatory responses in both epithelial and endothelial cells. Therefore, toxic effects induced by nZVI are not restricted to epithelial cells but can be transferred into the endothelium. Communication between A549 and EA.hy926 cells is responsible for amplification of nZVI-induced toxic responses. Decreases in transepithelial electrical resistance and zonula occludens proteins after epithelial exposure to nZVI impaired epithelial barrier integrity. Increases in oxidized α1-antitrypsin and oxidized low-density lipoprotein in the co-culture model suggest that nZVI exposure increases the risk of chronic obstructive pulmonary disease and atherosclerosis. Therefore, inhalation of nZVI has the potential to induce cardiovascular disease through oxidative and inflammatory mediators produced from the damaged lung epithelium in chronic lung diseases.

Consecutive evaluation of graphene oxide and reduced graphene oxide nanoplatelets immunotoxicity on monocytes

The biocompatibilities of graphene-family nanomaterials (GFNs) should be thoroughly evaluated before their application in drug delivery and anticancer therapy. The present study aimed to consecutively assess the immunotoxicity of graphene oxide nanoplatelets (GONPs) and reduced GONPs (rGONPs) on THP-1 cells, a human acute monocytic leukemia cell line. GONPs induced the expression of antioxidative enzymes and inflammatory factors, whereas rGONPs had substantially higher cellular uptake rate, higher levels of NF-κB expression. These distinct toxic mechanisms were observed because the two nanomaterials differ in their oxidation state, which imparts different affinities for the cell membrane. Because GONPs have a higher cell membrane affinity and higher impact on membrane proteins compared with rGONPs, macrophages (THP-1a) derived from GONPs treated THP-1cells showed a severer effect on phagocytosis. By consecutive evaluation the effects of GONPs and rGONPs on THP-1 and THP-1a, we demonstrated that their surface oxidation states may cause GFNs to behave differently and cause different immunotoxic effects.

Carbon black aggregates cause endothelial dysfunction by activating ROCK

Carbon black nanoparticles (CBNs) have been associated with the progression of atherosclerosis. CBNs normally enter the bloodstream and crosslink together to form agglomerates. However, most studies have used nano-sized CB particles to clarify the involvement of CBN exposure in CBN-induced endothelial dysfunction. Herein, we studied endothelial toxicity of CBN aggregates (CBA) to human EA.hy926 vascular cells. Cell viability, lactate dehydrogenase leakage, and oxidative stress were affected by the highest concentration of CBA. Moreover, transmission electron microscopic results showed that CBA entered cells through membrane enclosed vesicles. Rho-associated kinase (ROCK) is involved in regulating vascular diseases. Thus, we co-treated with the of ROCK inhibitor Y-27632 to study whether other adverse effects caused by CBA are related to activating ROCK. As expected, co-treatment with Y-27632 attenuated CBA-induced cytoskeletal damage, dysfunction of the endothelial barrier, and expression of inflammatory factors. Taken together, these results demonstrate that aggregated CBNs can cause endothelial dysfunction possibly by activating ROCK.

Industrial PM2.5 cause pulmonary adverse effect through RhoA/ROCK pathway

According to the Chinese Ministry of Health, industrial pollution-induced health impacts have been the leading cause of death in China. While industrial fine particulate matter (PM2.5) is associated with adverse health effects, the major action mechanisms of different compositions of PM2.5 are currently unclear. In this study, we treated normal human lung epithelial BEAS-2B cells with industrial organic and water-soluble PM2.5 extracts under daily alveolar deposition dose to elucidate the molecular mechanisms underlying adverse pulmonary effects induced by PM2.5, including oxidative damage, inflammatory response, lung epithelial barrier dysfunction, and the recruitment of macrophages. We found that water-soluble PM2.5 extracts caused more severe cytotoxic effects on BEAS-2B cells compared with that of organic extracts. Both organic and water-soluble PM2.5 extracts induced activation of the RhoA/ROCK pathway. Inflammatory response, epithelial barrier dysfunction, and the activation of NF-кB caused by both PM2.5 extracts were attenuated by ROCK inhibitor Y-27632. This indicated that both PM2.5 extracts could cause damage to epithelial cells through RhoA/ROCK-dependent NF-кB activation. Furthermore, the upregulation of macrophage adhesion induced by both PM2.5 extracts was also attenuated by Y-27632 in a co-culture model of macrophages and the epithelial cells. Therefore, our results support that industrial PM2.5 extracts-induced activation of the RhoA/ROCK-dependent NF-кB pathway induces pulmonary adverse effect. Thus, pharmacological inhibition of ROCK activation might have therapeutic potential in preventing lung disease associated with PM2.5.

ROCK inhibitor Y-27632 attenuated early endothelial dysfunction caused by occupational environmental concentrations of carbon black nanoparticles

The unique properties of carbon black nanoparticles (CBNs) make them feasible for new applications and raise concerns about cardiovascular disorders. Exposure to CBNs has been associated with the progression of atherosclerosis, whereas little is known about the mechanism. Here, we used CBNs to investigate whether the RhoA/Rho-associated coiled-coil containing protein kinase (ROCK) pathway is required to elevate the risk of developing endothelial dysfunction under realistic occupational environmental concentrations. The effect of a specific inhibitor of ROCK, Y-27632, on CBN-induced endothelial dysfunction was evaluated using endothelial monoculture and co-culture models. We evaluated the endothelial barrier integrity by measuring endothelial cell migration, transendothelial electrical resistance, tight-junction proteins, and cytoskeletal rearrangement. CBNs significantly induced endothelial barrier dysfunction, which was attenuated by Y-27632. Furthermore, upregulation of monocyte adhesion and migration was attenuated by Y-27632 in a co-culture model of monocytes, macrophages, and endothelial cells. Finally, a change in oxidized low-density lipoprotein and endothelial nitric oxide synthase, which contributes to the development of atherosclerosis, was also inhibited by Y-27632. Our results indicate that the RhoA/ROCK signaling pathway may upregulate inflammatory stress and mediate the development of early endothelial dysfunction induced by realistic occupational environmental concentrations of CBNs. Pharmacological inhibition of ROCK may have therapeutic potential in preventing CBN-associated endothelial dysfunction.