High-amylose starch: Structure, functionality and applications.

Starch with a high amylose (AM) content (high AM starch, HAS) has attracted increasing research attention due to its industrial application potential, such as functional foods and biodegradable packaging. In the past two decades, HAS structure, functionality, and applications have been the research hotspots. However, a review that comprehensively summarizes these areas is lacking, making it difficult for interested readers to keep track of past and recent advances. In this review, we highlight studies that benefited from rapidly developing techniques, and systematically review the structure, functionality, and applications of HAS. We particularly emphasize the relationships between HAS molecular structure and physicochemical properties.

Pollution Levels and Risk Assessment of Heavy Metals in the Soil of a Landfill Site: A Case Study in Lhasa, Tibet.

As an important ecological security barrier in China, the ecological environment of Tibet has aroused widespread concern domestically and overseas. Landfills are a major solid waste treatment approach in Tibet but also cause severe environmental pollution. To date, there are no studies related to the pollution risk of landfills in Tibetan areas. This study investigated the pollution levels, ecological risk, health risk, and possible pollution sources of eight heavy metals in the soils around a landfill site in Lhasa, Tibet. The results indicated that the concentrations of heavy metals in soil were relatively low, only cadmium (Cd), arsenic (As), copper (Cu), chromium (Cr), zinc (Zn), nickel (Ni), and lead (Pb) were 1-2 times higher than the corresponding background value. The values of the single pollution index and geo-accumulation index show that the study area is most seriously polluted by Cd and As. Based on the Nemerow pollution index and the pollution load index, over 83.3% and 8.33% of soil sampling sites had light and moderate contamination levels. According to the results of potential ecological risk evaluation, the potential ecological risk of heavy metals in soil was very low, and only one out of the 72 sampling sites exhibited considerable ecological risk. Cd, As, and mercury (Hg) served as the dominant ecological risk contributors and contributed over 45.0%, 14.1%, and 18% of the ecological risk. The results of the health risk evaluation showed that adults have a higher risk of cancer (1.73 × 10-5), while the non-carcinogenic risk for adults was low. Waste disposal activities and construction activities have a significant influence on soil heavy metal concentrations, causing a higher pollution level in the southeast part of the landfill site in Lhasa.

Inhibition of post-trabeculectomy fibrosis via topically instilled antisense oligonucleotide complexes co-loaded with fluorouracil.

Trabeculectomy is the mainstay of surgical glaucoma treatment, while the success rate was unsatisfying due to postoperative scarring of the filtering blebs. Clinical countermeasures for scar prevention are intraoperative intervention or repeated subconjunctival injections. Herein, we designed a co-delivery system capable of transporting fluorouracil and anti-TGF-ß2 oligonucleotide to synergistically inhibit fibroblast proliferation via topical instillation. This co-delivery system was built based on a cationic dendrimer core (PAMAM), which encapsulated fluorouracil within hydrophobic cavity and condensed oligonucleotide with surface amino groups, and was further modified with hyaluronic acid and cell-penetrating peptide penetratin. The co-delivery system was self-assembled into nanoscale complexes with increased cellular uptake and enabled efficient inhibition on proliferation of fibroblast cells. In vivo studies on rabbit trabeculectomy models further confirmed the anti-fibrosis efficiency of the complexes, which prolonged survival time of filtering blebs and maintained their height and extent during wound healing process, exhibiting an equivalent effect on scar prevention compared to intraoperative infiltration with fluorouracil. Qualitative observation by immunohistochemistry staining and quantitative analysis by Western blotting both suggested that TGF-ß2 expression was inhibited by the co-delivery complexes. Our study provided a potential approach promising to guarantee success rate of trabeculectomy and prolong survival time of filtering blebs.

Biomass molded fuel in China: Current status, policies and suggestions.

China is an agricultural country, approximately producing more than 1000 million tons of crop straw in 2018. The utilization of straw as energy can replace fossil fuels, protect environment and guarantee energy security. Biomass fuel has been regarded as renewable energy with the characteristics of carbon-neutral, and low emissions of nitrogen oxides and sulfur dioxide. Biomass molded fuel (BMF), a major type of biomass fuel, has attracted particular attention. Currently, the BMF industry in China develops slowly. To achieve the rapid and healthy development of the industry, in this paper, a three-part standard system as fuel side, production and combustion equipment side and pollutant emission side is proposed to regulate the BMF market. Simultaneously, a policy system consisting of legislation, development plans and incentive measures also is introduced to maintain policy consistency and continuity.

Contamination source apportionment and health risk assessment of heavy metals in soil around municipal solid waste incinerator: A case study in North China.

Few studies have comprehensively taken into account the source apportionment and human health risk of soil heavy metals in the vicinity of municipal solid waste incinerator (MSWI) in high population density area. In this study, 8 elements (Cr, Pb, Cu, Ni, Zn, Cd, Hg, and As) in fly ash, soil samples from different functional areas and vegetables collected surrounding the MSWI in North China were determined. The single pollution index, integrated Nemerow pollution index, principal component analysis (PCA), absolute principle component score-multiple linear regression (APCS-MLR) model and dose-response model were used in this study. The results showed that the soils around the MSWI were moderately polluted by Cu, Pb, Zn, and Hg, and heavily polluted by As and Cd. MSWI had a significant influence on the distribution of soil heavy metals in different distances from MSWI. The source apportionment results showed that MSWI, natural source, industrial discharges and coal combustion were the four major potential sources for heavy metals in the soils, with the contributions of 36.08%, 29.57%, 10.07%, and 4.55%, respectively. MSWI had a major impact on Zn, Cu, Pb, Cd, and Hg contamination in soil. The non-carcinogenic risk and carcinogenic risk posed by soil heavy metals surrounding the MSWI were unacceptable. The soil heavy metals concentrations and health risks in different functional areas were distinct. MSWI was the predominate source of non-carcinogenic risk with the average contribution rate of 36.99% and carcinogenic risk to adult male, adult female and children with 4.23×10-4, 4.57×10-4, and 1.41×10-4 respectively, implying that the impact of MSWI on human health was apparent. This study provided a new insight for the source apportionment and health risk assessment of soil heavy metals in the vicinity of MSWI.

A novel penetratin-modified complex for noninvasive intraocular delivery of antisense oligonucleotides.

Inhibition of gene expression by nucleic acids is a promising strategy in the treatment of ocular diseases. However, intraocular delivery of nucleic acids to the posterior ocular tissues remains a great challenge due to the presence of various biological barriers. To circumvent this problem, we established a novel penetratin (P) modified poly(amidoamine) dendrimer (D)/hyaluronic acid (H) complex to deliver antisense oligonucleotides (ASOs, O). Complexes (D/O, HD/O and PHD/O) were easily prepared and modification layers (hyaluronic acid and penetratin) were respectively absorbed on the surface via electrostatic interaction. Complexes with different outer layers were characterized as spherical particles with reversed charges. In vitro cellular uptake of ASOs in PHD/O complex was significantly increased than those in other formulations. In vivo studies were carried out after topical instillation of the complexes in the conjunctival sac of mice. Compared with D/O and HD/O, PHD/O exhibited much more distribution in the posterior segment of the eyes and prolonged retention time of ASOs in retina for more than 8h. Taken together, these results indicated that PHD/O complex possessed substantially improved ocular permeability and distribution in the posterior ocular tissues. This work provided a promising noninvasive intraocular delivery strategy for nucleic acids via topical administration.

Noninvasive delivery of oligonucleotide by penetratin-modified polyplexes to inhibit protein expression of intraocular tumor.

Our present study aimed to develop an antisense oligonucleotide (ASO) delivery system to achieve gene silencing in intraocular tumor via topical instillation. ASO specific for luciferase was chosen as model drug, polyamidoamine (PG5) was employed to condense ASO, and penetratin (Pene) was used to enhance cellular uptake. Nanoscale PG5/ASO/Pene polyplex was stabilized via noncovalent bonding. In vitro evaluations indicated that PG5/ASO/Pene exhibited improved cell-penetrating and gene silencing ability compared with naked ASO and PG5/ASO. Subcutaneous and orthotopic tumor models expressing luciferase were established in nude mice. After treated by PG5/ASO/Pene, immunohistochemical results of subcutaneous tumors showed significant inhibition of luciferase expression via peritumoral injection, and bioluminescence from orthotopic tumor was obviously weakened via topical instillation. To date, few works were successful in noninvasive treatment of intraocular diseases using antisense strategy, this penetratin-modified polyplex could be a promising vector to inhibit protein expression by effectively delivering ASOs into the eye.

Functionalized cell nucleus-penetrating peptide combined with doxorubicin for synergistic treatment of glioma.

UNLABELLED: Clinical application of cell-penetrating peptides (CPPs) in cancer therapy is greatly restricted due to lack of tissue selectivity and tumor-targeting ability. CB5005, a rationally designed CPP that targets and inhibits intracellular NF-κB activation, is constituted by a unique membrane-permeable sequence (CB5005M) cascading to a NF-κB nuclear localization sequence (CB5005N). In vitro cellular evaluation confirmed that CB5005 was effectively taken up by brain capillary endothelial cell bEnd.3 and glioma cells U87. The intracellular localization analysis further demonstrated that CB5005 could not only penetrate into the cells but also enter into their nuclei. More interestingly, CB5005 permeated deeply into the tumor spheroids of U87 cell. In vivo imaging illustrated that the fluorescence-labeled CB5005 distributed itself into the brain and accumulated at the tumor site after intravenous injection. Given the important role of over expressed NF-κB in tumor growth and development, we further investigated CB5005 for its potential in treatment of glioma. When combined administration in vitro with doxorubicin (DOX), CB5005 exhibited a synergistic effect in killing U87 cells. In a nude mice xenograft model, CB5005 inhibited the growth of tumor when applied alone, and displayed a synergistic anti-tumor effect with DOX. In conclusion, CB5005 functioned simultaneously as a cell penetrating peptide and a tumor growth inhibitor, therefore can work as a potential synergist for chemotherapy of human tumor. STATEMENT OF SIGNIFICANCE: Clinical application of cell-penetrating peptides in cancer therapy is restricted due to lack of tissue selectivity and tumor-targeting ability. In this manuscript, we reported a rationally designed peptide, named CB5005, which had an attractive capability of translocation into the cell nucleus and blocking nuclear translocation of endogenous NF-κB protein. CB5005 had unique affinity with brain and glioma, and could rapidly accumulate in these tissues after intravenous injection. Furthermore, CB5005 showed a synergistic effect on inhibiting gliomas when administrated with doxorubicin. This is the first literature report on this multi-functionalized peptide, which can work as a potential synergist for chemotherapy of tumor. This work should be of general interest to scientists in the fields of biomaterials, biology, pharmacy, and oncology.

Facile Noninvasive Retinal Gene Delivery Enabled by Penetratin.

Gene delivery to the posterior segment of the eye is severely hindered by the impermeability of defensive barriers; therefore, in clinical settings, genomic medicines are mainly administered by intravitreal injection. We previously found that penetratin could transport the covalently conjugated fluorophore to the fundus oculi by topical instillation. In this study, gene delivery systems enabled by penetratin were designed based on electrostatic binding to target the retina via a noninvasive administration route and prepared with red fluorescent protein plasmid (pRFP) and/or poly(amidoamine) dendrimer of low molecular weight (G3 PAMAM). Formulation optimization, structure confirmation, and characterization were subsequently conducted. Penetratin alone showed limited ability to condense the plasmid but had powerful uptake and transfection by corneal and conjunctival cells. G3 PAMAM was nontoxic to the ocular cells, and when introduced into the penetratin-incorporated complex, the plasmid was condensed more compactly. Therefore, further improved cellular uptake and transfection were observed. After being instilled in the conjunctival sac of rats, the intact complexes penetrated rapidly from the ocular surface into the fundus and resided in the retina for more than 8 h, which resulted in efficient expression of RFP in the posterior segment. Intraocular distribution of the complexes suggested that the plasmids were absorbed into the eyes through a noncorneal pathway during which penetratin played a crucial role. This study provides a facile and friendly approach for intraocular gene delivery and is an important step toward the development of noninvasive gene therapy for posterior segment diseases.

A stapled peptide antagonist of MDM2 carried by polymeric micelles sensitizes glioblastoma to temozolomide treatment through p53 activation.

Antagonizing MDM2 and MDMX to activate the tumor suppressor protein p53 is an attractive therapeutic paradigm for the treatment of glioblastoma multiforme (GBM). However, challenges remain with respect to the poor ability of p53 activators to efficiently cross the blood-brain barrier and/or blood-brain tumor barrier and to specifically target tumor cells. To circumvent these problems, we developed a cyclic RGD peptide-conjugated poly(ethylene glycol)-co-poly(lactic acid) polymeric micelle (RGD-M) that carried a stapled peptide antagonist of both MDM2 and MDMX (sPMI). The peptide-carrying micelle RGD-M/sPMI was prepared via film-hydration method with high encapsulation efficiency and loading capacity as well as ideal size distribution. Micelle encapsulation dramatically increased the solubility of sPMI, thus alleviating its serum sequestration. In vitro studies showed that RGD-M/sPMI efficiently inhibited the proliferation of glioma cells in the presence of serum by activating the p53 signaling pathway. Further, RGD-M/sPMI exerted potent tumor growth inhibitory activity against human glioblastoma in nude mouse xenograft models. Importantly, the combination of RGD-M/sPMI and temozolomide--a standard chemotherapy drug for GBM increased antitumor efficacy against glioblastoma in experimental animals. Our results validate a combination therapy using p53 activators with temozolomide as a more effective treatment for GBM.

Monitoring of pesticide residues levels in fresh vegetable form Heibei Province, North China.

In this study, 226 samples of seven types of domestic vegetables collected from several vegetable-growing regions in Hebei Province of China were tested for the presence of 38 different agricultural pesticides using a gas chromatograph equipped with electron capture and nitrogen phosphorus detectors. The aim of this study was to investigate the distribution of pesticides in main vegetables from Hebei Province. Results showed that, in 65.93% of the samples, no residues were found, 31.42% of the samples contained pesticide residues at or below the maximum residue levels (MRLs), and 2.65% of the samples contained pesticide residues above MRL. The most frequently detected pesticides were acephate (31), followed by cyhalothrin (15), bifenthrin (8), omethoate (6), isazophos (6), dimethoate (5), chlorpyrifos (2), and malathion (1). Some (1.33%) of the samples contained multiple residues. The results provide useful information on the current contamination status of a key agricultural area in North China, and points to the continuous monitoring and strict regulation of pesticide use on vegetables are necessary.

Penetratin, a potentially powerful absorption enhancer for noninvasive intraocular drug delivery.

Intraocular drug delivery is extraordinarily hampered by the impermeability of defensive barriers of the eye. In this study, the ocular permeability of fluorophore-labeled cell-penetrating peptides (CPPs), including penetratin, TAT, low molecular weight protamine, and poly(arginine)8, was investigated based on multilevel evaluations. The human conjunctival epithelial cell (NHC) was exposed to various CPPs to determine the cytotoxicity and cellular uptake. Ex vivo studies with rabbit cornea were performed using side-by-side diffusion chambers to evaluate the apparent permeability coefficients and acute tissue tolerance of the CPP candidates. Among all examined CPPs, penetratin shows an outstanding cellular uptake, by increasing more than 16 and 25 times at low and high concentrations, compared to the control peptide poly(serine)8 respectively. Additionally, the permeability of penetratin across excised cornea is 87.5 times higher in comparison with poly(serine)8. More importantly, after instilled in the conjunctival sac of rat eyes, fluorophore-labeled penetratin displayed a rapid and wide distribution in both anterior and posterior segment of the eye, and could be observed in the corneal epithelium and retina lasting for at least 6 h. Interestingly, penetratin showed the lowest ocular cell and tissue toxicities among all examined CPPs. The high ocular permeability of penetratin could be attributed to its amphipathicity and spatial conformation determined by circular dichroism. Taken together, these data demonstrate that penetratin is potentially useful as an absorption enhancer for intraocular drug delivery.

A novel small peptide as an epidermal growth factor receptor targeting ligand for nanodelivery in vitro.

The epidermal growth factor receptor (EGFR) serves an important function in the proliferation of tumors in humans and is an effective target for the treatment of cancer. In this paper, we studied the targeting characteristics of small peptides (AEYLR, EYINQ, and PDYQQD) that were derived from three major autophosphorylation sites of the EGFR C-terminus domain in vitro. These small peptides were labeled with fluorescein isothiocyanate (FITC) and used the peptide LARLLT as a positive control, which bound to putative EGFR selected from a virtual peptide library by computer-aided design, and the independent peptide RALEL as a negative control. Analyses with flow cytometry and an internalization assay using NCI-H1299 and K562 with high EGFR and no EGFR expression, respectively, indicated that FITC-AEYLR had high EGFR targeting activity. Biotin-AEYLR that was specifically bound to human EGFR proteins demonstrated a high affinity for human non-small-cell lung tumors. We found that AEYLR peptide-conjugated, nanostructured lipid carriers enhanced specific cellular uptake in vitro during a process that was apparently mediated by tumor cells with high-expression EGFR. Analysis of the MTT assay indicated that the AEYLR peptide did not significantly stimulate or inhibit the growth activity of the cells. These findings suggest that, when mediated by EGFR, AEYLR may be a potentially safe and efficient delivery ligand for targeted chemotherapy, radiotherapy, and gene therapy.

In vitro and in vivo evaluation of gliclazide push-pull osmotic pump coated with aqueous colloidal polymer dispersions.

The objective of present work was to design and evaluate gliclazide push-pull osmotic pump (PPOP) coated with aqueous colloidal polymer dispersions-Eudragit(®) RL 30D and Eudragit(®) RS 30D. The influence of diacetin, diethyl phthalate (DEP), dibutyl sebacate (DBS) and triethyl citrate (TEC) on the free Eudragit(®) RL 30D and Eudragit(®) RS 30D films as plasticizers on drug release were studied. Among these four plasticizers, diacetin offered the smoothest surface of the cast films, and it displayed greatest water vapor transmission coefficient. Free RL and RS films with diacetin also exhibited greatest erosion compared with the other three plasticizers. On the other hand, TEC, DEP and DBS showed greater water absorption. When compared with CA-coated gliclazide PPOP, Eudragit-coated ones showed a f(2) factor of 71.7, indicating the similarity between the release profile of the two formulations. The prepared Eudragit-coated gliclazide PPOP showed typical Zero-order release characteristics, with R being 0.9953. In the in vivo evaluation, the mean relative oral bioavailability of Eudragit-coated PPOP compared to CA-coated ones was 106.9%, demonstrating good bioequivalence. Both of their in vitro-in vivo correlation (IVIVC) showed linear relationship, with R(2) being 0.9955 (Eudragit-coated PPOP) and 0.9987 (CA-coated PPOP), respectively. These results suggested that PPOP coated with Eudragit(®) RL 30D and RS 30D could overcome drawbacks of organic solution coating and promote the development of PPOP.