Optogenetics has revolutionized the experimental interrogation of neural circuits and holds promise for the treatment of neurological disorders. It is limited, however, because visible light cannot ...penetrate deep inside brain tissue. Upconversion nanoparticles (UCNPs) absorb tissue-penetrating near-infrared (NIR) light and emit wavelength-specific visible light. Here, we demonstrate that molecularly tailored UCNPs can serve as optogenetic actuators of transcranial NIR light to stimulate deep brain neurons. Transcranial NIR UCNP-mediated optogenetics evoked dopamine release from genetically tagged neurons in the ventral tegmental area, induced brain oscillations through activation of inhibitory neurons in the medial septum, silenced seizure by inhibition of hippocampal excitatory cells, and triggered memory recall. UCNP technology will enable less-invasive optical neuronal activity manipulation with the potential for remote therapy.
Abstract
Optical characteristics of luminescent materials, such as emission profile and lifetime, play an important role in their applications in optical data storage, document security, diagnostics, ...and therapeutics. Lanthanide-doped upconversion nanoparticles are particularly suitable for such applications due to their inherent optical properties, including large anti-Stokes shift, distinguishable spectroscopic fingerprint, and long luminescence lifetime. However, conventional upconversion nanoparticles have a limited capacity for information storage or complexity to prevent counterfeiting. Here, we demonstrate that integration of long-lived Mn
2+
upconversion emission and relatively short-lived lanthanide upconversion emission in a particulate platform allows the generation of binary temporal codes for efficient data encoding. Precise control of the particle’s structure allows the excitation feasible both under 980 and 808 nm irradiation. We find that the as-prepared Mn
2+
-doped nanoparticles are especially useful for multilevel anti-counterfeiting with high-throughput rate of authentication and without the need for complex time-gated decoding instrumentation.
SCI is a time-sensitive debilitating neurological condition without treatment options. Although the central nervous system is not programmed for effective endogenous repairs or regeneration, ...neuroplasticity partially compensates for the dysfunction consequences of SCI.
The purpose of our study is to investigate whether early induction of hypothermia impacts neuronal tissue compensatory mechanisms. Our hypothesis is that although neuroplasticity happens within the neuropathways, both above (forelimbs) and below (hindlimbs) the site of spinal cord injury (SCI), hypothermia further influences the upper limbs' SSEP signals, even when the SCI is mid-thoracic.
A total of 30 male and female adult rats are randomly assigned to four groups (n = 7): sham group, control group undergoing only laminectomy, injury group with normothermia (37°C), and injury group with hypothermia (32°C +/-0.5°C).
The NYU-Impactor is used to induce mid-thoracic (T8) moderate (12.5 mm) midline contusive injury in rats. Somatosensory evoked potential (SSEP) is an objective and non-invasive procedure to assess the functionality of selective neuropathways. SSEP monitoring of baseline, and on days 4 and 7 post-SCI are performed.
Statistical analysis shows that there are significant differences between the SSEP signal amplitudes recorded when stimulating either forelimb in the group of rats with normothermia compared to the rats treated with 2h of hypothermia on day 4 (left forelimb, p = 0.0417 and right forelimb, p = 0.0012) and on day 7 (left forelimb, p = 0.0332 and right forelimb, p = 0.0133) post-SCI.
Our results show that the forelimbs SSEP signals from the two groups of injuries with and without hypothermia have statistically significant differences on days 4 and 7. This indicates the neuroprotective effect of early hypothermia and its influences on stimulating further the neuroplasticity within the upper limbs neural network post-SCI. Timely detection of neuroplasticity and identifying the endogenous and exogenous factors have clinical applications in planning a more effective rehabilitation and functional electrical stimulation (FES) interventions in SCI patients.
The rising demand for radiation detection materials in many applications has led to extensive research on scintillators
. The ability of a scintillator to absorb high-energy (kiloelectronvolt-scale) ...X-ray photons and convert the absorbed energy into low-energy visible photons is critical for applications in radiation exposure monitoring, security inspection, X-ray astronomy and medical radiography
. However, conventional scintillators are generally synthesized by crystallization at a high temperature and their radioluminescence is difficult to tune across the visible spectrum. Here we describe experimental investigations of a series of all-inorganic perovskite nanocrystals comprising caesium and lead atoms and their response to X-ray irradiation. These nanocrystal scintillators exhibit strong X-ray absorption and intense radioluminescence at visible wavelengths. Unlike bulk inorganic scintillators, these perovskite nanomaterials are solution-processable at a relatively low temperature and can generate X-ray-induced emissions that are easily tunable across the visible spectrum by tailoring the anionic component of colloidal precursors during their synthesis. These features allow the fabrication of flexible and highly sensitive X-ray detectors with a detection limit of 13 nanograys per second, which is about 400 times lower than typical medical imaging doses. We show that these colour-tunable perovskite nanocrystal scintillators can provide a convenient visualization tool for X-ray radiography, as the associated image can be directly recorded by standard digital cameras. We also demonstrate their direct integration with commercial flat-panel imagers and their utility in examining electronic circuit boards under low-dose X-ray illumination.
Achieving efficient photon upconversion under low irradiance is not only a fundamental challenge but also central to numerous advanced applications spanning from photovoltaics to biophotonics. ...However, to date, almost all approaches for upconversion luminescence intensification require stringent controls over numerous factors such as composition and size of nanophosphors. Here, we report the utilization of dielectric microbeads to significantly enhance the photon upconversion processes in lanthanide-doped nanocrystals. By modulating the wavefront of both excitation and emission fields through dielectric superlensing effects, luminescence amplification up to 5 orders of magnitude can be achieved. This design delineates a general strategy to converge a low-power incident light beam into a photonic hotspot of high field intensity, while simultaneously enabling collimation of highly divergent emission for far-field accumulation. The dielectric superlensing-mediated strategy may provide a major step forward in facilitating photon upconversion processes toward practical applications in the fields of photobiology, energy conversion, and optogenetics.
Descriptive secondary analysis of two spinal cord injury (SCI) animal models.
To compare the somatosensory evoked potential (SSEP) and motor behavioral (BBB) assessments of the two most used rodent ...SCI models (contusion and transection), to elucidate their functional similarity and differences over the acute phase of 3 weeks.
Neuro-electrophysiology SSEP and motor behavioral BBB assessments are used to provide a comparative analysis of the functional changes among various severities of contusion and transection SCI.
Adult male and female rats randomly grouped (n = 5) as following: mild (6.25 mm), moderate (12.5 mm), severe (25 mm), and very severe (50 mm) contusion as well as right T10 hemi-transection (RxI), left T8 and right T10 double hemi-transection (DxI), and T8 complete transection (CxI) injuries, plus the control group (laminectomy with no injury). Animal weight, body temperature, anesthesia, surgical procedures, electrophysiological SSEP monitoring, locomotion BBB scoring, and statistical analysis were identical among all animal groups.
Statistical analysis of the SSEP and BBB data from both contusion and transection injury models indicate significant differences (P < 0.05). The results also show remarkable similarity for the severe and very severe contusion injuries to the complete transection, the moderate contusion injury to the double hemi-transection, and the mild contusion injury to the T10 hemi-transection injury.
Although contusion and transection spinal cord injuries have two completely different pathophysiologies, their injury progress during acute phase follow a similar trend.
Non-alcoholic steatohepatitis is a chronic liver disease characterised by the presence of hepatic steatosis, inflammation, and hepatocellular injury, for which no Food and Drug Administration ...(FDA)-approved treatment exists. FGF19 is a hormone that regulates bile acid synthesis and glucose homoeostasis. We aimed to assess the safety and efficacy of NGM282, an engineered FGF19 analogue, for the treatment of non-alcoholic steatohepatitis.
In this randomised, double-blind, placebo-controlled, phase 2 study, we recruited patients aged 18–75 years with biopsy-confirmed non-alcoholic steatohepatitis as defined by the non-alcoholic steatohepatitis clinical research network histological scoring system, from hospitals and gastroenterology and liver clinics in Australia and the USA. Key eligibility criteria included a non-alcoholic fatty liver disease activity score of 4 or higher, stage 1–3 fibrosis, and at least 8% liver fat content. Patients were randomly assigned (1:1:1) via a web-based system and stratified by diabetic status to receive either 3 mg or 6 mg subcutaneous NGM282 or placebo. The primary endpoint was the absolute change from baseline to week 12 in liver fat content. Responders were patients who achieved a 5% or larger reduction in absolute liver fat content as measured by MRI-proton density fat fraction. Efficacy analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT02443116.
Between July 14, 2015, and Aug 30, 2016, 166 patients were screened across 18 sites in Australia and the USA. 82 patients were randomly assigned to receive 3 mg NGM282 (n=27), 6 mg NGM282 (n=28), or placebo (n=27). At 12 weeks, 20 (74%) patients in the 3 mg dose group and 22 (79%) in the 6 mg dose group achieved at least a 5% reduction in absolute liver fat content from baseline (relative risk 10·0 95% CI 2·6–38·7 vs 11·4 3·0–43·8, respectively; p<0·0001 for both comparisons) versus two (7%) in the placebo group. Overall, 76 (93%) of 82 patients experienced at least one adverse event, most of which were grade 1 (55 67%), and only five (6%) were grade 3 or worse. The most commonly (≥10%) reported adverse events were injection site reactions (28 34%), diarrhoea (27 33%), abdominal pain (15 18%), and nausea (14 17%). These adverse events were reported more frequently in the NGM282 groups compared with the placebo group. No life-threatening events or patient deaths occurred during the study.
NGM282 produced rapid and significant reductions in liver fat content with an acceptable safety profile in patients with non-alcoholic steatohepatitis. Further study of NGM282 is warranted in this patient population.
NGM Biopharmaceuticals.
NGM282, an engineered fibroblast growth factor 19 analogue, rapidly and significantly reduced liver fat content in a multicenter, randomized, double‐blind, placebo‐controlled study in patients with ...biopsy‐confirmed nonalcoholic steatohepatitis (NASH). However, it is unclear whether these changes would be accompanied by histological improvement. In this open‐label study, we assessed the histological efficacy of NGM282 in patients with biopsy‐confirmed nonalcoholic steatohepatitis. Paired liver biopsies from 43 patients who received subcutaneous NGM282 (1 mg, n = 24; 3 mg, n = 19) once daily for 12 weeks were evaluated blinded to time point, subject, and clinical information. At week 12, NGM282 significantly reduced nonalcoholic fatty liver disease activity score (NAS; −1.9; 95% confidence interval, −2.6 to −1.2; P < 0.001 in the 1 mg group; −2.2, −3.1 to −1.3; P < 0.001 in the 3 mg group) and fibrosis (−0.5; −0.9 to 0; P = 0.035 in the 3 mg group) scores. Overall, 50% and 63% of the patients receiving NGM282 1 mg or 3 mg, respectively, improved NAS by 2 or more points without fibrosis worsening. Of the patients receiving NGM282 1 mg or 3 mg, 25% and 42%, respectively, improved liver fibrosis by one stage or more without worsening of steatohepatitis. Treatment with NGM282 led to relative reductions in liver fat content (−58% and −67% in the 1 mg and 3 mg groups, respectively), corrected T1 (cT1; −8% and −9%), alanine aminotransferase (ALT) (−67% and −60%), aspartate aminotransferase (−57% and −52%), and fibrogenesis biomarkers neoepitope‐specific N‐terminal propeptide of type III collagen (Pro‐C3; −22% and −33%) and enhanced liver fibrosis score (ELF; −3% and −6%) at week 12. Greater reductions in Pro‐C3, ELF, and cT1, but not in liver fat content, 7alpha‐hydroxy‐4‐cholesten‐3‐one, or ALT, were observed in histological responders than in nonresponders. Conclusion: In this open‐label study, NGM282 improved the histological features of NASH in 12 weeks with significant reductions in NAS and fibrosis scores, accompanied by improvements in noninvasive imaging and serum markers.
Upconversion nanoparticle-mediated optogenetics enables remote delivery of upconverted visible light from a near-infrared light source to targeted neurons or areas, with the precision of a pulse of ...laser light in vivo for effective deep-tissue neuromodulation. Compared to conventional optogenetic tools, upconversion nanoparticle-based optogenetic techniques are less invasive and cause reduced inflammation with minimal levels of tissue damage. In addition to the optical stimulation, this design offers simultaneously temperature recording in proximity to the stimulated area. This chapter strives to provide life science researchers with an introduction to upconversion optogenetics, starting from the fundamental concept of photon upconversion and nanoparticle fabrication to the current state-of-the-art of surface engineering and device integration for minimally invasive neuromodulation.
Myelin formation has been identified as a modulator of neural plasticity. New tools are required to investigate the mechanisms by which environmental inputs and neural activity regulate myelination ...patterns. In this study, we demonstrate a microfluidic compartmentalized culture system with integrated electrical stimulation capabilities that can induce neural activity by whole cell and focal stimulation. A set of electric field simulations was performed to confirm spatial restriction of the electrical input in the compartmentalized culture system. We further demonstrate that electrode localization is a key consideration for generating uniform the stimulation of neuron and oligodendrocytes within the compartments. Using three configurations of the electrodes we tested the effects of subcellular activation of neural activity on distal axon myelination with oligodendrocytes. We further investigated if oligodendrocytes have to be exposed to the electrical field to induce axon myelination. An isolated stimulation of cell bodies and proximal axons had the same effect as an isolated stimulation of distal axons co-cultured with oligodendrocytes, and the two modes had a non-different result than whole cell stimulation. Our platform enabled the demonstration that electrical stimulation enhances oligodendrocyte maturation and myelin formation independent of the input localization and oligodendrocyte exposure to the electrical field.
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