The bionic optic nerve can mimic human visual physiology and is a future treatment for visual disorders. Photosynaptic devices could respond to light stimuli and mimic normal optic nerve function. By modifying (Poly(3,4-ethylenedioxythio-phene):poly (styrenesulfonate)) active layers with all-inorganic perovskite quantum dots, with an aqueous solution as the dielectric layer in this paper, we developed a photosynaptic device based on an organic electrochemical transistor (OECT). The optical switching response time of OECT was 3.7 s. To improve the optical response of the device, a 365 nm, 300 mW·cm ^-2 UV light source was used. Basic synaptic behaviors such as postsynaptic currents (0.225 mA) at a light pulse duration of 4 s and double pulse facilitation at a light pulse duration of 1 s and pulse interval of 1 s were simulated. By changing the way light stimulates, for example, by adjusting the intensity of the light pulses from 180 to 540 mW·cm ^-2, the duration from 1 to 20 s, and the number of light pulses from 1 to 20, the postsynaptic currents were increased by 0.350 mA, 0.420 mA, and 0.466 mA, respectively. As such, we realized the effective shift from short-term synaptic plasticity (100 s recovery of initial value) to long-term synaptic plasticity (84.3% of 250 s decay maximum). This optical synapse has a high potential for simulating the human optic nerve.
Humans ; Quantum Dots ; Bionics ; Oxides ; Optic Nerve

Semiconductor nanoparticles generate photoelectrons and photo-induced holes under light excitation, and thus may influence the growth of microbial cells. The highly oxidative holes may severely damage the cells, while the photoelectrons may promote microbial metabolism. In this study, we evaluated the effect of exogenous cadmium sulfide (CdS) nanoparticles on bacterial growth using OD₆₀₀ and colony forming unit (CFU) as indicators. The oxidase activities, the concentration of pyruvate and malondialdehyde, and the expression of relevant genes assessed by real-time fluorescent quantitative PCR were analyzed to investigate the effect of excited CdS on cellular metabolism. The results showed that the OD₆₀₀ and pyruvate accumulation of E. coli increased by 32.4% and 34.6%, respectively, under light conditions. Moreover, the relative expression level of the division protein gene ftsZ was increased more than 50%, and the tricarboxylic acid cycle pathway gene icdA and gltA increased by 86% and 103%, respectively. The results indicated that photoelectrons could be used by microorganisms, resulting in promoted growth and metabolism. This study gives a deep insight into the interaction between nanoparticles and bacteria.
Escherichia coli/metabolism* ; Nanoparticles ; Cadmium Compounds/metabolism* ; Quantum Dots

Zinc oxide quantum dots (ZnO QDs) were synthesized by gel-sol method and employed as the transdermal aloesin (Alo) carriers. ZnO QDs were surface-functionalized with amino using aminopropyltriethoxysilane (APTES). Alo was covalently bonded on the surface of ZnO QDs via N,N'-carbonyldiimidazole to obtain Alo NPs, which were characterized by transmission electron microscope (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analyzer (TGA). TEM images showed that ZnO QDs were analogously sphere and monodisperse with a reasonably narrow size distribution, of which was around 4 nm. The size of Alo NPs increased to around 8 nm due to the surface modification. The intense bands at around 3 400 cm and 1 200 cm in the FTIR spectrum of Alo NPs from the vibration of -OH indicated the linkage of Alo on the surface of ZnO QDs. The results of TGA analysis showed that the mass ratio of ZnO QDs and Alo were 39.27% and 35.14%, respectively. The penetration of Alo NPs was much higher than raw Alo according to the passive penetration experiments with Franz-type diffusion cells instrument using full-thickness cavy skin, which manifested the improvement of the penetration for Alo delivered by ZnO QDs. The pH-controlled drug release behavior was investigated. At pH 7.4, only a small amount of Alo (1.45% ± 0.21%) had been released after 2 h. In contrast, as incubation at pH 5.0 of which pH was similar to endosomal environment, Alo was released very fast (87.63% ± 0.46% in 2 h) from Alo NPs, confirming that Alo NPs could response to the pH and realize the intracellular drug release. The inhibitory effect of Alo NPs on tyrosinase was in a dose dependent manner. When the concentration of Alo NPs was 12.5 μg/mL, the inhibition rate was up to 40.32% ± 1.57%. All the results show that the Alo NPs hold a great potential in transdermal tyrosinase inhibition.
Administration, Cutaneous ; Animals ; Chromones ; administration & dosage ; Drug Delivery Systems ; Glucosides ; administration & dosage ; Guinea Pigs ; Monophenol Monooxygenase ; metabolism ; Nanoparticles ; Quantum Dots ; Zinc Oxide

Brain disease is one of the greatest threats to public health. Brain theranostics is recently taking shape, indicating the treatments of stroke, inflammatory brain disorders, psychiatric diseases, neurodevelopmental disease, and neurodegenerative disease. However, several factors, such as lack of endophenotype classification, blood-brain barrier (BBB), target determination, ignorance of biodistribution after administration, and complex intercellular communication between brain cells, make brain theranostics application difficult, especially when it comes to clinical application. So, a more thorough understanding of each aspect is needed. In this review, we focus on recent studies regarding the role of exosomes in intercellular communication of brain cells, therapeutic effect of graphene quantum dots, transcriptomics/epitranscriptomics approach for target selection, and in vitro/in vivo considerations.
Blood-Brain Barrier ; Brain Diseases ; Brain ; Classification ; Endophenotypes ; Exosomes ; Graphite ; Neurodegenerative Diseases ; Public Health ; Quantum Dots ; Stroke ; Theranostic Nanomedicine

BACKGROUND: Fat grafting, or lipofilling, represent frequent clinically used entities. The fate of these transplants is still not predictable, whereas only few animal models are available for further research. Quantum dots (QDs) are semiconductor nanocrystals which can be conveniently tracked in vivo due to photoluminescence. METHODS: Fat grafts in cluster form were labeled with cadmium-telluride (CdTe)-QD 770 and transplanted subcutaneously in a murine in vivo model. Photoluminescence levels were serially followed in vivo. RESULTS: Tracing of fat grafts was possible for 50 days with CdTe-QD 770. The remaining photoluminescence was 4.9%±2.5% for the QDs marked fat grafts after 30 days and 4.2%± 1.7% after 50 days. There was no significant correlation in the relative course of the tracking signal, when vital fat transplants were compared to non-vital graft controls. CONCLUSIONS: For the first-time fat grafts were tracked in vivo with CdTe-QDs. CdTe-QDs could offer a new option for in vivo tracking of fat grafts for at least 50 days, but do not document vitality of the grafts.
Adipocytes ; Adipose Tissue* ; Models, Animal ; Quantum Dots* ; Transplantation ; Transplants*

BACKGROUND AND OBJECTIVES: Maintaining a permissive microenvironment is essential for adequate nerve regeneration. Cell-based therapy has the potential based cell replacement and promotion of axonal growth. The adipose tissue derived mesenchymal stromal cells (Ad-MSC) attract interest because neuroregenerative and anti-inflammatory properties. The aim of this study was to evaluate the effects of canine and murine Ad-MSC transplantation on the sciatic nerve regeneration. METHODS: Forty Wistar rats were divided randomly into: control group - CG (n=8); denervated group - DG (n=8); decellularized vein group - VG (n=8); decellularized vein+canine MSC–cMSC (n=8); descellularized vein+murine MSC–mMSC (n=8). After 10-mm nerve gap, the tubulation technique was performed with decellularized vein filled with 10⁶ MSC labeled with quantum dots (Qtracker 665®). The sciatic nerve functional index (SFI) and electroneuromyography (ENMG) measurements were carried and morphometric and immunohistochemistry analysis of the tissue. RESULTS: The SFI values were higher in the cMSC and mMSC groups at day 27 (p<0.020) and day 35 (p<0.011). The ENMG analysis also revealed better results in the mMSC group. Density, number, and total area of the fibers were increased in the mMSC and cMSC groups. Brain-derived neurotrophic factor BDNF and S-100 protein positive immunoreactivity showed a higher expression for both in the nerve of the mMSC and cMSC groups. The MSC labeled with quantum dots were detected at day 35, indicating neuronal survival long after the nerve damage. CONCLUSIONS: Murine and canine Ad-MSC associated with decellularized vein scaffold had positive effects on sciatic nerve regeneration in rats.
Adipose Tissue ; Animals ; Axons ; Brain-Derived Neurotrophic Factor ; Immunohistochemistry ; Mesenchymal Stromal Cells* ; Nerve Regeneration ; Neurons ; Peripheral Nerves* ; Quantum Dots ; Rats ; Rats, Wistar ; Regeneration* ; Regenerative Medicine ; S100 Proteins ; Sciatic Nerve ; Veins

Nanotechnology is the engineering and manipulation of materials and devices with sizes in the nanometer range. Colloidal gold, iron oxide nanoparticles and quantum dot semiconductor nanocrystals are examples of nanoparticles, with sizes generally ranging from 1 to 20 nm. These nanotechnologies have been researched tremendously in the last decade and this has led to a new area of “nanomedicine” which is the application of nanotechnology to human healthcare for diagnosis, monitoring, treatment, prediction and prevention of diseases. Recently progress has been made in overcoming some of the difficulties in the human use of nanomedicines. In the mid-1990s, Doxil was approved by the FDA, and now various nanoconstructs are on the market and in clinical trials. However, there are many obstacles in the human application of nanomaterials. For translation to clinical use, a detailed understanding is needed of the chemical and physical properties of particles and their pharmacokinetic behavior in the body, including their biodistribution, toxicity, and biocompatibility. In this review, we provide a broad introduction to nanomedicines and discuss the preclinical and clinical trials in which they have been evaluated.
Delivery of Health Care ; Diagnosis ; Gold Colloid ; Humans ; Iron ; Nanomedicine ; Nanoparticles ; Nanostructures ; Nanotechnology ; Quantum Dots

OBJECTIVETo study the effects of graphene quantum dots (GQDs) on hematopoietic system in rats.

METHODSThirty male SD rats were randomly divided into three groups (n = 10): control group, high dose group (10 mg/kg · d), low dose group (5 mg/kg · d), The rats in experimental group were intravenous injected with GQDs for 28 days and those in control group were injected with normal saline at the same volume. Routine blood and the function of liver and kidney were detected by instrument analysis. The cycle and apoptosis of bone marrow mononuclear cells (BMCs) were detected by FCM. The other three only healthy male SD rat bone marrow mononuclear cells (BMCs) were cultured by joining GQDs for 24 h, 48 h,72 h in vitro, the proliferation was assayed by CCK-8, the content of granulocyte macrophage colony stimulating factor (GM-CSF) from cultural supernatants were detected by ELISA.

RESULTSThe amount of red blood cell and concentration of hemoglobin from experimental group were increased significantly compared with those of control groups (P < 0.05), the concentration of triglyceride and high density lipoprotein were decreased. DNA synthesis period was prolonged (P < 0.01), there was no significant difference in apoptosis. BMCs were promoted proliferation clearly after using GQDs for 72 h (P < 0.05). The content of GM-CSF was increased (P < 0.01) .

CONCLUSIONGQDs may promote hematopoietic function in rats.

Animals ; Apoptosis ; Bone Marrow Cells ; drug effects ; Granulocyte-Macrophage Colony-Stimulating Factor ; metabolism ; Graphite ; pharmacology ; Hematopoiesis ; drug effects ; Male ; Quantum Dots ; chemistry ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo evaluate the bio-safety of graphene quantum dots (GQDs), we studied its effects on the embryonic development of zebrafish.

METHODSIn vivo, biodistribution and the developmental toxicity of GQDs were investigated in embryonic zebrafish at exposure concentrations ranging from 12.5-200 μg/mL for 4-96 h post-fertilization (hpf). The mortality, hatch rate, malformation, heart rate, GQDs uptake, spontaneous movement, and larval behavior were examined.

RESULTSThe fluorescence of GQDs was mainly localized in the intestines and heart. As the exposure concentration increased, the hatch and heart rate decreased, accompanied by an increase in mortality. Exposure to a high level of GQDs (200 μg/mL) resulted in various embryonic malformations including pericardial edema, vitelline cyst, bent spine, and bent tail. The spontaneous movement significantly decreased after exposure to GQDs at concentrations of 50, 100, and 200 μg/mL. The larval behavior testing (visible light test) showed that the total swimming distance and speed decreased dose-dependently. Embryos exposed to 12.5 μg/mL showed hyperactivity while exposure to higher concentrations (25, 50, 100, and 200 μg/mL) caused remarkable hypoactivity in the light-dark test.

CONCLUSIONLow concentrations of GQDs were relatively non-toxic. However, GQDs disrupt the progression of embryonic development at concentrations exceeding 50 μg/mL.

Animals ; Behavior, Animal ; Dose-Response Relationship, Drug ; Embryo, Nonmammalian ; abnormalities ; drug effects ; Graphite ; administration & dosage ; chemistry ; toxicity ; Larva ; drug effects ; Quantum Dots ; administration & dosage ; chemistry ; toxicity ; Zebrafish ; embryology

Optical imaging techniques use visual and near infrared rays. Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage. Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system. This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications. Emerging new optical imaging techniques and their potential are also described.
Contrast Media/diagnostic use ; Fluorescent Dyes/diagnostic use ; Humans ; Lymph Nodes/pathology/*radiography ; Lymphatic System/*pathology ; Lymphography ; Magnetic Resonance Imaging ; *Optical Imaging ; Positron-Emission Tomography ; Quantum Dots/diagnostic use ; Spectroscopy, Near-Infrared