Short-Term Facilitation of Long-Range Corticocortical Synapses Revealed by Selective Optical Stimulation.

Short-term plasticity regulates the strength of central synapses as a function of previous activity. In the neocortex, direct synaptic interactions between areas play a central role in cognitive function, but the activity-dependent regulation of these long-range corticocortical connections and their impact on a postsynaptic target neuron is unclear. Here, we use an optogenetic strategy to study the connections between mouse primary somatosensory and motor cortex. We found that short-term facilitation was strong in both corticocortical synapses, resulting in far more sustained responses than local intracortical and thalamocortical connections. A major difference between pathways was that the synaptic strength and magnitude of facilitation were distinct for individual excitatory cells located across all cortical layers and specific subtypes of GABAergic neurons. Facilitation was dependent on the presynaptic calcium sensor synaptotagmin-7 and altered by several optogenetic approaches. Current-clamp recordings revealed that during repetitive activation, the short-term dynamics of corticocortical synapses enhanced the excitability of layer 2/3 pyramidal neurons, increasing the probability of spiking with activity. Furthermore, the properties of the connections linking primary with secondary somatosensory cortex resemble those between somatosensory-motor areas. These short-term changes in transmission properties suggest long-range corticocortical synapses are specialized for conveying information over relatively extended periods.

Breathing-Assisted Selective Adsorption of C8 Alkyl Aromatics in Zn-Based Metal-Organic Frameworks.

The breathing phenomenon in metal-organic frameworks (MOFs) has revealed supramolecular host-guest interactions that could be beneficial for chemical separation in numerous industrial applications. The cost-effective purification of C8 alkyl aromatics such as o-xylene, m-xylene, p-xylene, and ethylbenzene remains challenging owing to their similar molecular structures, boiling points, kinetic diameters, polarities, etc. Herein, we report two Zn-based pillar-bilayered MOFs, denoted [Zn2 (aip)2 (pillar)] (aip=5-aminoisophthalic acid; pillar: bpy=4,4'-bipyridine or bpe=1,2-bis(4-pyridyl)ethane) that exhibit a breathing effect depending on the adsorbed guest molecules. Guest-dependent sorption studies in organic solvents such as N,N-dimethylformamide, methanol, benzene, and water vapor display reversible structural flexibility through the breathing effect in both framework compounds. The experiments conducted on C8 -alkyl aromatics resulting in both MOF compounds can access these isomers in the shrunken pores, and thereby expand the pore size by framework breathing. In C8 binary mixtures, these Zn-MOFs exhibit selective sorption properties based on the different interactions between guest C8 aromatics and the framework structure.

Breathing-Assisted Selective Adsorption of C8 Alkyl Aromatics in Zn-Based Metal-Organic Frameworks.

Invited for the cover of this issue are Purna Chandra Rao, Minyoung Yoon and co-workers at Kyungpook National University, Gachon University, POSTECH, Korea Atomic Energy Research Institute and the University of Sydney. The image depicts how single C8 isomers are selectively isolated from a mixture. Read the full text of the article at 10.1002/chem.202102640.

Association of mGluR-Dependent LTD of Excitatory Synapses with Endocannabinoid-Dependent LTD of Inhibitory Synapses Leads to EPSP to Spike Potentiation in CA1 Pyramidal Neurons.

The input-output relationships in neural circuits are determined not only by synaptic efficacy but also by neuronal excitability. Activity-dependent alterations of synaptic efficacy have been extensively investigated, but relatively less is known about how the neuronal output is modulated when synaptic efficacy changes are associated with neuronal excitability changes. In this study, we demonstrate that paired pulses of low-frequency stimulation (PP-LFS) induced metabotropic glutamate receptor (mGluR)-dependent LTD at Schaffer collateral (SC)-CA1 synapses in Sprague Dawley rats (both sexes), and this LTD was associated with EPSP to spike (E-S) potentiation, leading to the increase in action potential (AP) outputs. Threshold voltage (Vth) for APs evoked by synaptic stimulation and that by somatic current injection were hyperpolarized significantly after PP-LFS. Blockers of GABA receptors mimicked and occluded PP-LFS effects on E-S potentiation and Vth hyperpolarization, suggesting that suppression of GABAergic mechanisms is involved in E-S potentiation after PP-LFS. Indeed, IPSCs and tonic inhibitory currents were reduced after PP-LFS. The IPSC reduction was accompanied by increased paired-pulse ratio, and abolished by AM251, a blocker for Type 1 cannabinoid receptors, suggesting that PP-LFS suppresses presynaptic GABA release by mGluR-dependent endocannabinoids signaling. By contrast, a Group 1 mGluR agonist, 3, 5-dihydroxyphenylglycine, induced LTD at SC-CA1 synapses but failed to induce significant IPSC reduction and AP output increase. We propose that mGluR signaling that induces LTD coexpression at excitatory and inhibitory synapses regulates an excitation-inhibition balance to increase neuronal output in CA1 neurons.SIGNIFICANCE STATEMENT Long-lasting forms of synaptic plasticity are usually associated with excitability changes, the ability to fire action potentials. However, excitability changes have been regarded to play subsidiary roles to synaptic plasticity in modifying neuronal output. We demonstrate that, when metabotropic glutamate receptor-dependent LTD is induced by paired pulses of low-frequency stimulation, the action potential output in response to a given input paradoxically increases, indicating that increased excitability is more powerful than synaptic depression. This increase is mediated by the suppression of a presynaptic GABA release via metabotropic glutamate receptor-dependent endocannabinoid signaling. Our study shows that neuronal output changes do not always follow the direction of synaptic plasticity at excitatory synapses, highlighting the importance of regulating inhibitory tone via endocannabinoid signaling.

Thermal and Optical Performance of Glass Cloth Reinforced Organic-Inorganic Hybrid Polymer Composite Film.

Recently there has been considerable interest in flexible display as the next-generation display. The flexible plastic has been recommended as a strong candidate for substrate, but these plastic substrates have many problems to provide the comparable properties of dimensional stability, thermal stability, and solvent resistance to glass in order to apply conventional thin film transistor technology to flexible display. Then in this study, a glass cloth reinforced polymer (GCRP) composite was prepared. To improve the thermal property, glass cloth with an excellent coefficient of thermal expansion (CTE) for reinforcement and organic-inorganic hybrid nanomaterial with polyhedral oligomeric silsesquioxane (POSS) material having excellent heat resistance were introduced to ensure the excellent properties like transmittance, haze, yellow index, thermal stability and chemical resistance. The optical property of GCRP composite was measured by using a spectrophotometer and the CTE of GCRP composite was observed by thermomechanical analysis (TMA).

Costimulation of AMPA and metabotropic glutamate receptors underlies phospholipase C activation by glutamate in hippocampus.

Glutamate, a major neurotransmitter in the brain, activates ionotropic and metabotropic glutamate receptors (iGluRs and mGluRs, respectively). The two types of glutamate receptors interact with each other, as exemplified by the modulation of iGluRs by mGluRs. However, the other way of interaction (i.e., modulation of mGluRs by iGluRs) has not received much attention. In this study, we found that group I mGluR-specific agonist (RS)-3,5-dihydroxyphenylglycine (DHPG) alone is not sufficient to activate phospholipase C (PLC) in rat hippocampus, while glutamate robustly activates PLC. These results suggested that additional mechanisms provided by iGluRs are involved in group I mGluR-mediated PLC activation. A series of experiments demonstrated that glutamate-induced PLC activation is mediated by mGluR5 and is facilitated by local Ca(2+) signals that are induced by AMPA-mediated depolarization and L-type Ca(2+) channel activation. Finally, we found that PLC and L-type Ca(2+) channels are involved in hippocampal mGluR-dependent long-term depression (mGluR-LTD) induced by paired-pulse low-frequency stimulation, but not in DHPG-induced chemical LTD. Together, we propose that AMPA receptors initiate Ca(2+) influx via the L-type Ca(2+) channels that facilitate mGluR5-PLC signaling cascades, which underlie mGluR-LTD in rat hippocampus.

Functional dynamics and selectivity of two parallel corticocortical pathways from motor cortex to layer 5 circuits in somatosensory cortex.

In the rodent whisker system, active sensing and sensorimotor integration are mediated in part by the dynamic interactions between the motor cortex (M1) and somatosensory cortex (S1). However, understanding these dynamic interactions requires knowledge about the synapses and how specific neurons respond to their input. Here, we combined optogenetics, retrograde labeling, and electrophysiology to characterize the synaptic connections between M1 and layer 5 (L5) intratelencephalic (IT) and pyramidal tract (PT) neurons in S1 of mice (both sexes). We found that M1 synapses onto IT cells displayed modest short-term depression, whereas synapses onto PT neurons showed robust short-term facilitation. Despite M1 inputs to IT cells depressing, their slower kinetics resulted in summation and a response that increased during short trains. In contrast, summation was minimal in PT neurons due to the fast time course of their M1 responses. The functional consequences of this reduced summation, however, were outweighed by the strong facilitation at these M1 synapses, resulting in larger response amplitudes in PT neurons than IT cells during repetitive stimulation. To understand the impact of facilitating M1 inputs on PT output, we paired trains of inputs with single backpropagating action potentials, finding that repetitive M1 activation increased the probability of bursts in PT cells without impacting the time-dependence of this coupling. Thus, there are two parallel but dynamically distinct systems of M1 synaptic excitation in L5 of S1, each defined by the short-term dynamics of its synapses, the class of postsynaptic neurons, and how the neurons respond to those inputs.

Functional Dynamics and Selectivity of Two Parallel Corticocortical Pathways from Motor Cortex to Layer 5 Circuits in Somatosensory Cortex.

In the rodent whisker system, active sensing and sensorimotor integration are mediated in part by the dynamic interactions between the motor cortex (M1) and somatosensory cortex (S1). However, understanding these dynamic interactions requires knowledge about the synapses and how specific neurons respond to their input. Here, we combined optogenetics, retrograde labeling, and electrophysiology to characterize the synaptic connections between M1 and layer 5 (L5) intratelencephalic (IT) and pyramidal tract (PT) neurons in S1 of mice (both sexes). We found that M1 synapses onto IT cells displayed modest short-term depression, whereas synapses onto PT neurons showed robust short-term facilitation. Despite M1 inputs to IT cells depressing, their slower kinetics resulted in summation and a response that increased during short trains. In contrast, summation was minimal in PT neurons due to the fast time course of their M1 responses. The functional consequences of this reduced summation, however, were outweighed by the strong facilitation at these M1 synapses, resulting in larger response amplitudes in PT neurons than IT cells during repetitive stimulation. To understand the impact of facilitating M1 inputs on PT output, we paired trains of inputs with single backpropagating action potentials, finding that repetitive M1 activation increased the probability of bursts in PT cells without impacting the time dependence of this coupling. Thus, there are two parallel but dynamically distinct systems of M1 synaptic excitation in L5 of S1, each defined by the short-term dynamics of its synapses, the class of postsynaptic neurons, and how the neurons respond to those inputs.

Rat primary cortical cell tri-culture to study effects of amyloid-beta on microglia function.

Introduction: The etiology and progression of sporadic Alzheimer's Disease (AD) have been studied for decades. One proposed mechanism is that amyloid-beta (Aß) proteins induce neuroinflammation, synapse loss, and neuronal cell death. Microglia play an especially important role in Aß clearance, and alterations in microglial function due to aging or disease may result in Aß accumulation and deleterious effects on neuronal function. However, studying these complex factors in vivo , where numerous confounding processes exist, is challenging, and until recently, in vitro models have not allowed sustained culture of microglia, astrocytes and neurons in the same culture. Here, we employ a tri-culture model of rat primary neurons, astrocytes, and microglia and compare it to co-culture (neurons and astrocytes) and mono-culture enriched for microglia to study microglial function (i.e., motility and Aß clearance) and proteomic response to exogenous Aß. Methods: We established cortical co-culture (neurons and astrocytes), tri-culture (neurons, astrocytes, and microglia), and mono-culture (microglia) from perinatal rat pups. On days in vitro (DIV) 7 - 14, the cultures were exposed to fluorescently-labeled Aß (FITC-Aß) particles for varying durations. Images were analyzed to determine the number of FITC-Aß particles after specific lengths of exposure. A group of cells were stained for ßIII-tubulin, GFAP, and Iba1 for morphological analysis via quantitative fluorescence microscopy. Cytokine profiles from conditioned media were obtained. Live-cell imaging with images acquired every 5 minutes for 4 hours was employed to extract microglia motility parameters (e.g., Euclidean distance, migration speed, directionality ratio). Results and discussion: FITC-Aß particles were more effectively cleared in the tri-culture compared to the co-culture. This was attributed to microglia engulfing FITC-Aß particles, as confirmed via epifluorescence and confocal microscopy. Adding FITC-Aß significantly increased the size of microglia, but had no significant effect on neuronal surface coverage or astrocyte size. Analysis of the cytokine profile upon FITC-Aß addition revealed a significant increase in proinflammatory cytokines (TNF-α, IL-1α, IL-1ß, IL-6) in tri-culture, but not co-culture. In addition, Aß addition altered microglia motility marked by swarming-like motion with decreased Euclidean distance yet unaltered speed. These results highlight the importance of cell-cell communication in microglia function (e.g., motility and Aß clearance) and the utility of the tri-culture model to further investigate microglia dysfunction in AD.

Electrophysiological Activity of Primary Cortical Neuron-Glia Mixed Cultures.

Neuroinflammation plays a central role in many neurological disorders, ranging from traumatic brain injuries to neurodegeneration. Electrophysiological activity is an essential measure of neuronal function, which is influenced by neuroinflammation. In order to study neuroinflammation and its electrophysiological fingerprints, there is a need for in vitro models that accurately capture the in vivo phenomena. In this study, we employed a new tri-culture of primary rat neurons, astrocytes, and microglia in combination with extracellular electrophysiological recording techniques using multiple electrode arrays (MEAs) to determine the effect of microglia on neural function and the response to neuroinflammatory stimuli. Specifically, we established the tri-culture and its corresponding neuron-astrocyte co-culture (lacking microglia) counterpart on custom MEAs and monitored their electrophysiological activity for 21 days to assess culture maturation and network formation. As a complementary assessment, we quantified synaptic puncta and averaged spike waveforms to determine the difference in excitatory to inhibitory neuron ratio (E/I ratio) of the neurons. The results demonstrate that the microglia in the tri-culture do not disrupt neural network formation and stability and may be a better representation of the in vivo rat cortex due to its more similar E/I ratio as compared to more traditional isolated neuron and neuron-astrocyte co-cultures. In addition, only the tri-culture displayed a significant decrease in both the number of active channels and spike frequency following pro-inflammatory lipopolysaccharide exposure, highlighting the critical role of microglia in capturing electrophysiological manifestations of a representative neuroinflammatory insult. We expect the demonstrated technology to assist in studying various brain disease mechanisms.

Experiential Learning in a Biomedical Device Engineering Course: Proposal Development and Raw Research Data-Based Assignments.

There is a need for novel teaching approaches to train biomedical engineers that are conversant across disciplines and have the technical skills to address interdisciplinary scientific and technological challenges. Here, we describe a graduate-level miniaturized biomedical device engineering course that has been taught over the last decade in in-person, remote, and hybrid formats. The course employs experiential learning components, including a proposal development and review that mimic the National Institutes of Health process and technical assignments that use raw research data to simulate a research experience. The effectiveness of the course was measured via pre-/post-course concept inventory surveys as well as course evaluations with targeted questions on the learning instruments. Statistical comparison of pre-/post-course survey scores suggests that the course was effective in students achieving the learning objectives, and comparison of relative increase in pre-/post-course survey scores across different instruction formats (i.e., in-person, remote, hybrid) showed minimal difference, suggesting that the teaching elements are readily transferrable to remote instruction. Supplementary Information: The online version contains supplementary material available at 10.1007/s43683-022-00094-z.

Primary Cortical Cell Tri-Culture-Based Screening of Neuroinflammatory Response in Toll-like Receptor Activation.

The activation of toll-like receptors (TLRs) in the central nervous system (CNS) can lead to neuroinflammation and contribute to many neurological disorders, including autoimmune diseases. Cell culture models are powerful tools for studying specific molecular and cellular mechanisms that contribute to these disease states and identifying potential therapeutics. However, most cell culture models have limitations in capturing biologically relevant phenomena, due in part to the non-inclusion of necessary cell types. Neurons, astrocytes, and microglia (critical cell types that play a role in neuroinflammation) all express at least a subset of TLRs. However, the response of each of these cell types to various TLR activation, along with their relative contribution to neuroinflammatory processes, is far from clear. In this study, we demonstrate the screening capabilities of a primary cortical cell tri-culture of neuron, astrocyte, and microglia from neonatal rats. Specifically, we compare the neuroinflammatory response of tri-cultures to that of primary neuron-astrocyte co-cultures to a suite of known TLR agonists. We demonstrate that microglia are required for observation of neurotoxic neuroinflammatory responses, such as increased cell death and apoptosis, in response to TLR2, 3, 4, and 7/8 activation. Additionally, we show that following TLR3 agonist treatment, microglia and astrocytes play opposing roles in the neuroinflammatory response, and that the observed response is dictated by the degree of TLR3 activation. Overall, we demonstrate that microglia play a significant role in the neuroinflammatory response to TLR activation in vitro and, hence, the tri-culture has the potential to serve as a screening platform that better replicates the in vivo responses.

Dopamine Receptor Supports the Potentiation of Intrinsic Excitability and Synaptic LTD in Temporoammonic-CA1 Synapse.

Dopaminergic projection to the hippocampus from the ventral tegmental area or locus ceruleus has been considered to play an essential role in the acquisition of novel information. Hence, the dopaminergic modulation of synaptic plasticity in the hippocampus has been widely studied. We examined how the D1 and D2 receptors influenced the mGluR5-mediated synaptic plasticity of the temporoammonic-CA1 synapses and showed that the dopaminergic modulation of the temporoammonic-CA1 synapses was expressed in various ways. Our findings suggest that the dopaminergic system in the hippocampal CA1 region regulates the long-term synaptic plasticity and processing of the novel information.

Barriers and Facilitators of Obtaining Social Determinants of Health of Patients With Cancer Through the Electronic Health Record Using Natural Language Processing Technology: Qualitative Feasibility Study With Stakeholder Interviews.

BACKGROUND: Social determinants of health (SDoH), such as geographic neighborhoods, access to health care, education, and social structure, are important factors affecting people's health and health outcomes. The SDoH of patients are scarcely documented in a discrete format in electronic health records (EHRs) but are often available in free-text clinical narratives such as physician notes. Innovative methods like natural language processing (NLP) are being developed to identify and extract SDoH from EHRs, but it is imperative that the input of key stakeholders is included as NLP systems are designed. OBJECTIVE: This study aims to understand the feasibility, challenges, and benefits of developing an NLP system to uncover SDoH from clinical narratives by conducting interviews with key stakeholders: (1) oncologists, (2) data analysts, (3) citizen scientists, and (4) patient navigators. METHODS: Individuals who frequently work with SDoH data were invited to participate in semistructured interviews. All interviews were recorded and subsequently transcribed. After coding transcripts and developing a codebook, the constant comparative method was used to generate themes. RESULTS: A total of 16 participants were interviewed (5 data analysts, 4 patient navigators, 4 physicians, and 3 citizen scientists). Three main themes emerged, accompanied by subthemes. The first theme, importance and approaches to obtaining SDoH, describes how every participant (n=16, 100%) regarded SDoH as important. In particular, proximity to the hospital and income levels were frequently relied upon. Communication about SDoH typically occurs during the initial conversation with the oncologist, but more personal information is often acquired by patient navigators. The second theme, SDoH exists in numerous forms, exemplified how SDoH arises during informal communication and can be difficult to enter into the EHR. The final theme, incorporating SDoH into health services research, addresses how more informed SDoH can be collected. One strategy is to empower patients so they are aware about the importance of SDoH, as well as employing NLP techniques to make narrative data available in a discrete format, which can provide oncologists with actionable data summaries. CONCLUSIONS: Extracting SDoH from EHRs was considered valuable and necessary, but obstacles such as narrative data format can make the process difficult. NLP can be a potential solution, but as the technology is developed, it is important to consider how key stakeholders document SDoH, apply the NLP systems, and use the extracted SDoH in health outcome studies.

One-step-immunoassay of procalcitonin enables rapid and accurate diagnosis of bacterial infection.

Procalcitonin (PCT) (i.e. a precursor of calcitonin) attracts much attention as a reliable biomarker of bacterial infections because its concentration increases rapidly in the blood when bacterial infections occur in the body. Sepsis may occur due to indiscriminate and vigorous proliferation of infectious bacteria, and accordingly early diagnosis and treatment of bacterial infection are of crucial importance. However, current diagnostic methods for sepsis suffer from long assay time, multiple and complex assay steps, inaccuracy, and requirement of analytical equipments. The goal of this study is to develop an advanced one-step-immunoassay that enables quick and accurate diagnosis of sepsis through measuring the PCT concentration in patient sera, which is based on self-enhancement of optical detection signals from large gold particles (i.e. clusters of gold nanoparticles) that are formed on the agglomerates of PCT-bound 3-dimensional (3D) probes. The 3D probe is constructed through attaching polyclonal anti-PCT antibodies (IgGs) to the surface of a modified hepatitis B virus (HBV) capsid, where both tandem repeats of the B domain of Staphylococcal protein A (SPAB) and the hexa-histidine tag are inserted into each HBV core protein (i.e. subunit of HBV capsid). That is, anti-PCT IgGs are attached via strong interaction between the Fc region and surface-exposed SPAB. Furthermore, hook effect-free and PCT concentration-dependent optical signals were consistently generated by adding both bovine serum albumin (BSA) and nickel ions to patient sera and also by optimally adjusting the 3D probe concentration. Compared to conventional chemiluminescent microparticle immunoassay (CMIA) showing poor linearity of detection signals, this novel immunoassay accurately detected PCT with good linearity between PCT concentrations and optical signals in a wide range of PCT concentrations (0.05-200 ng mL-1) and also showed a sufficiently low limit of detection, resulting in 100% sensitivity and 100% specificity when tested with 30 sepsis patients and 30 healthy individuals.

Avenanthramide C Prevents Neuronal Apoptosis via PI3K/Akt/GSK3ß Signaling Pathway Following Middle Cerebral Artery Occlusion.

Avenanthramides are a group of phenolic alkaloids that have been shown to have anti-inflammatory, anti-oxidant, anti-atherogenic, and vasodilation effects. The aim of the present study was to investigate the neuroprotective effect of avenanthramide-c (Avn-c) in focal brain ischemia and reperfusion injury using middle cerebral artery occlusion (MCAo) model with mice. Male C57BL/6 mice were divided into 4 groups: sham, control (MCAo), Avn-c, and Avn-c + LY294002 (phosphoinositide 3-kinase inhibitor) group. They were subjected to 60 min MCAo followed by reperfusion. Brain infarct volume and neurological deficit scores were measured after 24 h of reperfusion. We evaluated the blood brain barrier (BBB) integrity (ZO-1, VE-cadherin and occludin) and apoptosis (Bax, Bcl2, caspase3, Cytochrome C, and poly ADP ribose polymerase(PARP)-1). We also measured GSK3ß for evaluation of the downstream mechanism of Akt. We examined the effect of the Avn-c in the phosphoinositide 3-kinase pathway. Avn-c reduced neurological score and infarction size. Avn-c inhibited the MCAo-induced disruption of tight junction proteins. Avn-c decreased apoptotic protein expression (Bax, Cytochrome C, and cleaved PARP-1) and increased anti-apoptotic protein expression (Bcl2) after MCAo. Akt and GSK3ß were decreased in MCAo group and were restored in Avn-c group. This effect of Avn-c was abolished by PI3K inhibitor. In summary, Avn-c showed neuroprotective effects through PI3K-Akt-GSK3ß signaling pathway.

Thiol chitosan-wrapped gold nanoshells for near-infrared laser-induced photothermal destruction of antibiotic-resistant bacteria.

Developing new antibacterial nanomaterials and novel therapeutic strategies for the destruction of human pathogenic bacteria that cause infectious diseases is becoming more crucial, because infections caused by antibiotic-resistant bacteria are becoming more and more difficult to be effectively cured with commercially available antibiotics. In this study, we successfully developed new thiol chitosan-wrapped gold nanoshells (TC-AuNSs) as an antibacterial agent for the near-infrared (NIR) laser-triggered photothermal destruction of antibiotic-resistant pathogens, such as Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), owing to their high water solubility, biocompatibility, strong NIR absorption, and outstanding photothermal properties. More interestingly, TC-AuNSs (115 µg/mL) were capable of completely destroying S. aureus, P. aeruginosa, and E.coli within 5 min of NIR laser irradiation, and no bacterial growth was detected on the tryptic soy agar (TSA) plate after 48 h of laser irradiation, indicating that TC-AuNSs along with laser irradiation are highly efficient and can kill bacteria quickly and prevent bacterial regrowth. We believe that TC-AuNSs deserve much more attention as an antibacterial agent, to be used in effectively combating pathogenic bacteria associated with public health problems and monitoring of environmental pollution for hygiene and safety.

Symmetry-guided syntheses of mixed-linker Zr metal-organic frameworks with precise linker locations.

While the one-pot reaction of zirconium metal ions with a mixture of two dicarboxylate heterolinkers yielded a 12-c fcu Zr MOF with randomly distributed linkers, the symmetry-guided stepwise reaction produced the same MOF with both linkers precisely located in the framework. In the latter method, linear terephthalic acid (H2BDC) derivatives with mmm symmetry were inserted into the mmm-symmetry sites of the flexible Zr MOF with 8-c bcu topology (ZRN-bcu), which is composed of zigzag 2,6-naphthalenedicarboxylic acid with 2/m symmetry. Although the length of the symmetry-matching BDC2- derivatives was much shorter than the distance between the unlinked nearest-neighbor Zr clusters in ZRN-bcu, induced fitting of the derivatives into the framework was possible, resulting in well-defined locations for the two different dicarboxylate linkers. Thus, controlled synthesis of MOFs with the desired topology and functionality can be achieved using a symmetry-guided approach.

Anti-EGFR antibody conjugated thiol chitosan-layered gold nanoshells for dual-modal imaging-guided cancer combination therapy.

Developing a novel multifunctional theranostic agent for cancer combination therapy has attracted tremendous attention in recent years. In this report, we designed and developed a new multifunctional nanocarrier based on anti-epidermal growth factor receptor antibody-conjugated and paclitaxel loaded-thiol chitosan-layered gold nanoshells (anti-EGFR-PTX-TCS-GNSs) as a theranostic agent for the first time used for fluorescence/photoacoustic dual-modal imaging-guided chemophotothermal synergistic therapy. The resulting anti-EGFR-PTX-TCS-GNSs showed excellent biosafety, biocompatibility, broad near-infrared (NIR) absorbance, photostability, fast and laser irradiation-controllable drug release, and higher targeting efficiency for efficient chemophotothermal combination therapy of cancer under the guidance of photoacoustic imaging (PAI). The combination therapy was investigated in vitro and in vivo, displaying a powerful anticancer efficiency. More importantly, an in vivo experiment of anti-EGFR-PTX-TCS-GNSs with laser irradiation showed heavy damage to the tumor tissue, killing the tumor cells almost completely. Anti-EGFR-PTX-TCS-GNSs also showed a powerful capacity to visualize tumors, and therefore it is considered a new PAI contrast agent for subsequent therapy. Histological analysis and TUNEL assay further showed much more apoptotic cells, confirming the value of anti-EGFR-PTX-TCS-GNSs. Our results provide a new concept and a promising strategy to develop a novel multifunctional nanotheranostic agent for future clinical applications in diagnosis and therapy.

Chitosan/fucoidan multilayer coating of gold nanorods as highly efficient near-infrared photothermal agents for cancer therapy.

Photothermal therapy (PTT) using chitosan/fucoidan multilayer coating of gold nanorods (CS/F-GNRs) has emerged as an alternative strategy for cancer therapy. In this study, biocompatible CS/F-GNRs were synthesized as a new generation of photothermal therapeutic agents for in vivo cancer treatments owing to their good biocompatibility, photostability, and strong absorption in the near-infrared (NIR) region. The CS/F-GNRs showed a good size distribution (51.87 ± 3.03 nm), and the temperature variation of the CS/F-GNRs increased by 54.4 °C after laser irradiation (1.0 W/cm2) for 5 min. The in vitro photothermal efficiency of CS/F-GNRs indicated that significantly more cancer cells were killed under laser irradiation at 1.0 W/cm2 for 5 min. On the 20th day of treatment, the MDA-MB-231 tumor cells in mice treated with CS/F-GNRs under laser irradiation had almost completely disappeared. Therefore, the biocompatible CS/F-GNRs have shown great promise as safe and highly efficient near-infrared photothermal agents for future cancer therapy.