As nanomedicines are developing fast in both academic and market areas, building up suitable methods for nanomedicine analysis with proper techniques is an important subject, requiring further research. The techniques, which could be employed for grain size analysis of nanomedicines, were reviewed. Several key techniques were discussed with their principles, scope of applications, advantages and defects. Their applications to nanomedine analysis were discussed according to the properties of different nanomedicines, with the purpose of providing some suggestions for the control and administration of nanomedicines.
Drug Delivery Systems ; Light ; Microscopy, Electron ; methods ; Microscopy, Scanning Probe ; methods ; Nanoparticles ; analysis ; chemistry ; classification ; Particle Size ; Scattering, Radiation ; Scattering, Small Angle ; Spectrum Analysis, Raman ; methods ; X-Ray Diffraction ; methods

OBJECTIVE: To develop a fast, sensitive and cost-effective method based on resonance light scattering (RLS) for characterization of protein solubility to facilitate detection of changes in solubility of mutant proteins. METHODS: We examined the response curve of RLS intensities to the protein concentrations in synchronous scanning mode. The curve intersection points were searched to predict the maximal concentrations of the protein in dispersion state, which defined the solubility of the protein in this given state. Bovine serum albumin (BSA, 0-50 g/L) was used as the model to investigate the influences of pH values (6.5, 7.0, and 7.4) and salt concentrations (0.05, 0.10, 0.15, and 0.20 mol/L) on the determined solubility. The solubility of glutathione S-transferase isoenzymes alpha (GSTA, 0-27.0 g/L) and Mμ (GSTM, 0-20.0 g/L) were estimated for comparison. The RLS-based method was used to determine the solubility of uricase (MGU, 0-0.4 g/L) to provide assistance in improving the solubility of its mutants. RESULTS: We identified two intersection points in the RLS response curves of the tested proteins, among which the lower one represented an approximation of the maximal concentration (or the solubility of the protein) in single molecular dispersion, and the higher one the saturated concentration of the protein in multiple molecular aggregation. In HEPES buffer, the two intersection points of BSA (isoelectric point 4.6) both increased with the increase of pH (6.5-7.4), and their values were ~1.2 g/L and ~33 g/L at pH 7.4, respectively; the latter concentration approached the solubility of commercial BSA in the same buffer at the same pH. The addition of NaCl reduced the values of the two intersection points, and increasing salt ion concentration decreased the values of the lower intersection points. Further characterizations of GSTA and GSTM showed that the low concentration intersection points of the two proteins were ~0.7 g/L and ~0.8 g/L, and their high concentration intersection points were ~10 g/L and ~11 g/L, respectively, both lower than those of BSA, indicating the feasibility of the direct characterization of protein solubility by RLS. The two concentration intersection points of MGU were 0.24 g/L and 0.30 g/L, respectively, and the low concentration intersection point of its selected mutant was increased by 2 times. CONCLUSIONS RLS allows direct characterization of the solubility of macromolecular proteins. This method, which is simple and sensitive and needs only a small amount of proteins, has a unique advantage for rapid comparison of solubility of low-abundance protein mutants.
Hydrogen-Ion Concentration ; Light ; Scattering, Radiation ; Solubility ; Spectrum Analysis

Silver nanoparticles were synthesized from the extract of Fagopyri Dibotryis Rhizoma and the optimization of synthesis was studied. The absorbance of UV-visible spectroscopy was determined under the different influencing factors such as extracting time of Fagopyri Dibotryis Rhizoma powder, reation temperature of synthesis, volume of Fagopyri Dibotryis Rhizoma extract and concentration of AgNO3 to seek the optimization conditions. By means of FT-IR, TEM, DLS and XRD, the silver nanoparticles were characterized. The results showed that when the boiling time of Fagopyri Dibotryis Rhizoma powder was 5 min, resultant temperature was 25 degrees C, the volume ratio of 0.1 g x mL(-1) Fagopyri Dibotryis Rhizoma extract and 1 mmol x L(-1) AgNO3 was 1 to 10, and the reaction time was 3.5 h, the obtained silver nanoparticles had mean size about 27 nm and Zeta potential about -34.3 mV with good uniformity and dispersivity. Therefore, the green synthesis method of silver nanoparticles using extract of traditional Chinese medicine is stable and feasible.
Fagopyrum ; chemistry ; Light ; Metal Nanoparticles ; chemistry ; ultrastructure ; Microscopy, Electron, Transmission ; Particle Size ; Plant Extracts ; chemistry ; Rhizome ; chemistry ; Scattering, Radiation ; Silver ; chemistry ; Silver Nitrate ; chemistry ; Spectroscopy, Fourier Transform Infrared ; Temperature ; X-Ray Diffraction

The fundamental research field of medical ultrasound has been the characterization of tissue scatterers. The signal processing method is widely used in this research field. A new method of Chirp-Z Transform Cepstrum for mean spacing estimation of tissue scatterers using ultrasonic scattered signals has been developed. By using this method together with conventional AR cepstrum method, we processed the backscattered signals of mimic tissue and pig liver in vitro. The results illustrated that the Chirp-Z Transform Cepstrum method is effective for signal analysis of ultrasonic scattering and characterization of tissue scatterers, and it can improve the resolution for mean spacing estimation of tissue scatterers.
Algorithms ; Animals ; Computer Simulation ; Humans ; Liver ; diagnostic imaging ; Scattering, Radiation ; Signal Processing, Computer-Assisted ; Swine ; Ultrasonography

Biotic tissues are a kind of highly scattering random media; studies on laser light propagation in biotic tissues play an important role in bio-medical diagnostics and therapeutics. The propagation and distribution of infinitely narrow photon beam in tissues are simulated by Monte Carlo method in this paper. Also presented are the energy distribution with regard to depths, light distribution in tissues, reflection and transmittance on the upper and lower surface. The optical parameters adopted in this study are g, albedo and microa, which have influence on energy distribution. The results show: The energy distribution decreases more quickly with the increase of depths and reveals a peak value close to the surface; g factor plays an important part in the lost energy on the upper surface and lower surface; the decrease of g factor causes weaking of the forward moving ability, so the penetration depth becomes smaller and the energy becomes dispersives variation of albedo has distinct effect on the shallow and deep tissues.
Computer Simulation ; Energy Transfer ; Light ; Models, Biological ; Monte Carlo Method ; Optics and Photonics ; Photochemotherapy ; methods ; Scattering, Radiation

In order to study the light propagation in biological tissue, we analyzed the divergent beam propagation in turbid medium. We set up a Monte Carlo simulation model for simulating the divergent beam propagation in a semi-infinite bio-tissue. Using this model, we studied the absorbed photon density with different tissue parameters in the case of a divergent beam injecting the tissue. The simulation results showed that the rules of optical propagation in the tissue were found and further the results also suggested that the diagnosis and treatment of the light could refer to the rules of optical propagation.
Computer Simulation ; Light ; Models, Biological ; Monte Carlo Method ; Optics and Photonics ; Scattering, Radiation

OBJECTIVETo establish a HPLC-ELSD fingerprint of Marsdenia tenacissima from different habitats, in order to provide a reliable method for scientific assessment and effective quality control.

METHODHPLC-ELSD was adopted to determine 25 baches of M. tenacissima herbs from different habitats. Traditional Chinese medicine chromatographic fingerprint similarity software assessment system 2004 developed by China Pharmacopoeia Committee was adopted to establish a common mode chart and assess chromatographic similarity based on the degree of correlation.

RESULTThe common mode for M. tenacissima herb C21 steroidal fingerprint was established, including 11 common characteristic peaks. Among them, 10 were identified. According to the assessment on the similarity of 25 batches of samples, 80% of them showed a similarity of over 0.80 in steroidal HPLC-ELSD fingerprint.

CONCLUSIONThe method can be used to assess the quality of M. tenacissima.

OBJECTIVETo establish the fingerprints of the active fractions from Tian-wang-bu-xin-wan decoction by HPLC, and to explain the role of Radix Platycodi in the decoction prescription.

METHODThe experimental conditions of the HPLC method were established as follows: Hanbon Lichrospher C18 column (4.6 mm x 250 mm, 5 microm), mobile phase were methanol and 0.012 5 mol L(-1) ammonium acetate/acetic acid buffer, eluted with a linear gradient, flow rate was 1.0 mL min(-1), the photodiode array detector (PDA) and evaporative light scattering detector (ELSD) were connected in series.

RESULTIn the same conditions and used same method, the extract amount of whole prescription was higher than that of excepting Radix Platycodi. The method provided two kinds of fingerprints with satisfied separation, which were the HPLC-PDA (Max Plot) fingerprint and the HPLC-ELSD fingerprint. And, they had good correlation and complementaritiy.

CONCLUSIONThe Radix Platycodi can enhance the decoction yield of the prescription; and increase the dissolution and the contents of some ingredients in the decoction.

Scatter coincident events are the important factor that affects the quality of positron emission tomography (PET) images. In this paper, according to the characters of projection data, a scatter correction method which uses maximum likelihood expectation maximization (MLEM) algorithm based on poisson model is proposed. We compared the sinograms and reconstructed images corrected by MLEM algorithm and deconvolution method respectively. The results indicate that the algorithm proposed in this paper increases the contrast of images while correcting scatter. It is better than the traditional method.
Algorithms ; Image Processing, Computer-Assisted ; methods ; Nonlinear Dynamics ; Poisson Distribution ; Positron-Emission Tomography ; methods ; Scattering, Radiation

OBJECTIVETo determine such molecular characteristic parameters as absolute molecular weight, molecular weight distribution, root-mean-square turning radius (Rg) and polydispersity index (Mw/Mn) of four components contained in Hedysari Radix polysaccharide 3 (HPS-3) and map weight-average molecular weight (Mw) with root-mean-square turning radius (Rg), in order to calculate conformations of the four components at solution state.

METHODThe gel permeation chromatography-multi angle laser light scatting (GPC-MALLS) was adopted, with 0.1 mol x L(-1) NaNO3 contained 0.02% NaN3 as the mobilephase, Ultrahydrogel 1000 connected in series with Ultrahydrogel500.

RESULTAmong the four components of HPS-3, HPS-3-C showed the highest weight average molecular weight of 1.986 x 10(5) g x mol(-1), followed by HPS-3-B 1.113 x 10(5) g x mol(-1) and HPS-3-D 8.457 x 10(4) g x mol(-1) HPS-3-A showed the lowest weight average molecular weight of 1. 223 x 10(4) g x mol(-1) but the highest square radius of gyration, that is 55.5 nm. HPS-3-D had the widest range of molecular weight distribution in four components, with the polydispersity index (Mw/Mn) of 2.543. In the mobile phase, HPS-3-A was globular structure, HPS-3-C was random coil, HPS-3-B and HPS-3-D were both highly branched structure.

CONCLUSIONThe results provided necessary basis for further studies on molecular characteristics of the four components contained in HPS-3 and their relationship with bioactivity.