A wearable gamma radiation-responsive granulocyte colony-stimulating factor microneedle system protecting against ionizing radiation-induced injury.

Exposure to a nuclear accident or a radiological attack may cause serious death events due to ionizing radiation-induced injury and acute radiation syndrome (ARS). Recombinant human granulocyte colony-stimulating factor (G-CSF) is now used for the treatment of ARS. However, the current injection formulation might not ensure treatment as early as possible after a nuclear accident, resulting in a decrease in therapeutic efficiency. In the present study, we have developed a G-CSF wearable system (GWS) consisting of a commercial microchip, a temperature sensor, a gamma-ray detection sensor, a flexible heater, and a G-CSF temperature-sensitive microneedle (GTSMN) patch. G-CSF-containing hyaluronic acid solutions were cast into the mold to obtain G-CSF microneedles (GMNs), which were coated with a temperature-sensitive layer of dodecanoic acid-cetylamine salt to obtain GTSMNs. The flexible heater was prepared by jet printing Ag nanoparticle inks. The GWS and its components are explored and optimized in the aspects of electronics, mechanics, heat transfer and drug diffusion. The γ radiation signal is sensitively monitored by the GWS. The wearable G-CSF system immediately releases G-CSF into the body in response to signal feedback and provides maximal protection against ionizing radiation-induced injury. Therefore, the GWS is a promising wearable system against emergent ionizing radiation injury. STATEMENT OF SIGNIFICANCE: Ionizing radiation-induced injury is always the very important public health problem all the global people care. Some medicines have been applied to protect the body from the injury. Unfortunately, sometimes the injuries accidently happen and the medicines cannot be administered in time, leading to serious acute radiation syndrome. Here, we design a wearable system loading G-CSF that has been approved by FDA to protect the body from ionizing radiation-induced injury. This system consists of a commercial microchip, a temperature sensor, a Gamma-ray detection sensor, a flexible heater, and a G-CSF temperature-sensitive microneedle patch. It can monitor γ radiation and immediately release G-CSF into the body to protect the body to the maximal extent. Therefore, the system is a promising wearable medical device against emergent ionizing radiation injury.

X-band TE101 rectangular aperture cavity for in vivo EPR tooth dosimetry after radiation emergency.

The TE101 mode rectangle EPR cavity was newly developed to achieve X-band in vivo EPR tooth dosimetry for the rescue of nuclear emergency. An aperture for sample detection was opened on the cavity's surface. Its characteristics were evaluated by measuring DPPH and intact human incisor samples. Remarkable radiation induced signal from EPR spectrum of 1Gy-8Gy irradiated teeth was observed. In vivo measurements of rat was performed to verify its application for in vivo tooth dosimetry.

Functional expression and purification of recombinant full-length human ATG7 protein with HIV-1 Tat peptide in Escherichia coli.

The human autophagy-related protein ATG7 (hATG7), an E1-like ubiquitin enzyme, activates two ubiquitin-like proteins, LC3 (Atg8) and Atg12, and promotes autophagosome formation. While hATG7 plays an essential role for the autophagy conjugation system, the production of full-length functional hATG7 in bacterial systems remains challenging. Previous studies have demonstrated that the HIV-1 virus-encoded Tat peptide ('GRKKRRQRRR') can increase the yield and solubility of heterologous proteins. Here, functional full-length hATG7 was expressed using the pET28b-Tat expression vector in the Escherichia coli BL21 (DE3) strain. Recombinant hATG7 protein aggregated as inclusion bodies while expressed with widely used prokaryotic expression plasmids. In contrast, the solubility of Tat-tagged hATG7 increased significantly with prolonged time compared to Tat-free hATG7. The recombinant proteins were purified to >90% homogeneity under native conditions with a single step of affinity chromatography purification. The results of in vitro pull-down and LC3B-I lipidation assays showed that Tat-tagged hATG7 directly interacted with LC3B-I and promoted LC3B-I lipidation, suggesting that Tat-tagged hATG7 has significant catalytic activity. Overall, this study provides a novel method for improving the functional expression of full-length hATG7 in bacterial systems by fusion with the Tat peptide, a process which may be applied in future studies of hATG7 structure and function.

The design of X-band EPR cavity with narrow detection aperture for in vivo fingernail dosimetry after accidental exposure to ionizing radiation.

For the purpose of assessing the radiation dose of the victims involved in the nuclear emergency or radiation accident, a new type of X-band EPR resonant cavity for in vivo fingernail EPR dosimetry was designed and a homemade EPR spectrometer for in vivo fingernail detection was constructed. The microwave resonant mode of the cavity was rectangular TE101, and there was a narrow aperture for fingernail detection opened on the cavity's wall at the position of high detection sensitivity. The DPPH dot sample and the fingernail samples were measured based on the in vivo fingernail EPR spectrometer. The measurements of the DPPH dot sample verified the preliminary functional applicable of the EPR spectrometer and illustrated the microwave power and modulation response features. The fingernails after irradiation by gamma-ray were measured and the radiation-induced signal was acquired. The results indicated that the cavity and the in vivo EPR dosimeter instrument was able to detect the radiation-induced signal in irradiated fingernail, and preliminarily verified the basic function of the instrument and its potential for emergency dose estimate after a radiation accident.

A normalization method of the volume and geometry of tooth for X-band in vivo EPR dosimetry.

The accuracy of in vivo EPR tooth dosimetry may be influenced by the volume and geometry variations in teeth, especially when there is considerable non-uniform sensitivity distribution in the active detection area of the cavity. To solve this problem, the present research proposed a normalization method specifically for X-band EPR in vivo tooth dosimetry. The volume and geometry of the measured tooth were reconstructed by digital image processing with images of the tooth impression slices, which were obtained by a custom-made impression module. The sensitivity distribution in the active detection area was established based on experiments with a point sample. Consequently, a composite normalization process that could calibrate the evaluated dose effectively was carried out by taking into account the influences not only from tooth volume and geometry but also from the non-uniform distribution of sensitivity. The effect and practicability of the method were evaluated by incisor samples. Results showed that the standard deviation could be reduced a maximum of 54.8% approximately after the composite normalization, an improvement compared to results from solely tooth volume. The correlation coefficient of the dose-response curve could be improved from 0.731 to 0.986. The preliminary method provides an approach potentially useful on site after radiation accidents when dealing with the influence of variations in the tooth volume and geometry for X-band EPR in vivo dose estimations.

Study of new practical ESR dosimeter based on carbonated hydroxyapatite and its dosimetric properties.

The development of new dosimeters with good dosimetric properties is important for quality control in radiation applications. A new practical electron spin resonance (ESR) dosimeter based on carbonated hydroxyapatite that simulated the composition and structure of tooth enamel was specially synthesized. The synthesized material was investigated by transmission electron microscope, X-ray diffraction, fourier transform infrared spectroscopy and X-ray photo electron spectroscopy to confirm to the main composition of carbonated hydroxyapatite with CO32- successfully doped into the crystal lattice through optimizing the synthesis process of C/P molar ratio, pH value dynamical adjustment, annealing temperature and time. The dosimetric properties were systematically investigated by ESR spectroscopy. The results indicated that the radiation induced signal had a good dose response within a relatively wide dose range. The dose response was linear in the dose range of 0-400 Gy with a correlation coefficient of 0.9999 and had dose accumulative effect in the experimental dose range of 0-100 Gy. In a wider dose range up to 30 kGy, the dose response also presented linear feature in double-logarithmic coordinate system with a correlation coefficient of 0.9970. The dose detection limit was about 0.34Gy with a given probability of 95% confidence level depending upon a rigid calculation algorithm. The signal was extremely stable in the observation time of 360 days with a variation coefficient of 3.8%. The radiation sensitivity of the material showed no remarkable variation against photon energy from 662 KeV to 1.25 MeV and dose rate from 0.86 Gy/min to 12.17 Gy/min. The material showed more sensitive in lower photon energy range below 662 keV, which hint additional calibration may need when using in special photon energy condition. The preliminary results suggested that this newly developed dosimeter was potential to become a practical dosimeter that would expand the application fields of ESR dosimetry.

Effect of the tooth surface water on the accuracy of dose reconstructions in the X-band in vivo EPR dosimetry.

The X-band in vivo EPR tooth dosimetry is promising as a tool for the initial triage after a large-scale radiation accident. The dielectric losses caused by water on the tooth surface (WTS) are one of the major sources of inaccuracies in this method. The effect was studied by theoretical simulation calculations and experiments with water films of various thicknesses on teeth. The results demonstrate the possibility of sufficiently accurate measurements of the radiation-induced signal of the tooth enamel provided that the thickness of the water film on the tooth is below 60 µm. The sensitivity of the cavity decreases with increasing thickness of the water layer. The interference of WTS can be diminished by normalization of the radiation-induced signal to the signal of a reference sample permanently present in the cavity.

The Application and Distribution of Magnetic Field Modulation in the Detection Apertures of X-band EPR Cavities for In Vivo Tooth Dosimetry.

In vivo electron paramagnetic resonance tooth dosimetry could be a practical and ideal tool for quick mass triage of victims in the rescue following a disaster event involving irradiation radiation. Magnetic field modulation is an important issue to improve the sensitivity of X-band in vivo tooth dosimetry. We designed a couple of trapezoidal modulation coil sets fixed on the magnet poles that could be used to apply sufficient magnet field modulation into the detection aperture of the resonant cavity. Measurements of irradiated teeth with such coil sets demonstrated significant radiation-induced signals. The modulation generation efficiencies and magnetic field distributions in apertures with different cavity geometries were analytically calculated, simulated by a finite element method and evaluated by measurements of a free radical point sample to study the influences caused by the geometries of the apertures and other factors.

Calibration ruler for CW-EPR distance measurement using diradical molecule of rigid structure.

Many experimental factors and uncontrollable factors may introduce errors in the distance measurement by continuous wave electron paramagnetic resonance. To deal with this problem, several C60 nitroxide diradical adducts with rigid structure and definite molecular dimension were used as distance calibration rulers. Based on the improvement of distance calculation program via adding simulation programs of experimental spectra and dipolar broadening function, respectively, the distance calibration method was developed under different conditions such as different solvent, solution concentration, measuring temperature, and microwave power. As a result, stable distance calibration rulers were established within the range of 8-13 Å. The distance calibration effect was evaluated resulting in a corresponding distance measurement precision of 0.84 Å. The results suggested that the influence of non-dipolar spectral broadening factors could be overcome, and the established experimental and calculation methods were suitable to a wide range of situations. The developed method will ensure more accurate and objective distance measurement in biomacromolecular analysis.