Detection and elimination of trace d-lactic acid in lignocellulose biorefining chain: Generation, flow, and impact on chiral lactide synthesis.

High chiral purity of lactic acid is a crucial indicator for the synthesis of chiral lactide as the primary intermediate chemical for ring-open polymerization of high molecular weight polylactic acid (PLA). Lignocellulose biomass is the most promising carbohydrate feedstock for commercial production of PLA, but the presence of trace d-lactic acid in the biorefinery chain adversely affects the synthesis and quality of chiral lactide. This study analyzed the fingerprint of trace  d-lactic acid in the biorefinery chain and found that the major source of  d-lactic acid comes from lignocellulose feedstock. The naturally occurring lactic acid bacteria and water-soluble carbohydrates in lignocellulose feedstock provide the necessary conditions for  d-lactic acid generation. Three strategies were proposed to eliminate the generation pathway of  d-lactic acid, including reduction of moisture content, conversion of water-soluble carbohydrates to furan aldehydes in pretreatment, and conversion to  l-lactic acid by inoculating engineered  l-lactic acid bacteria. The natural reduction of lactic acid content in lignocellulose feedstock during storage was observed due to the lactate oxidase-catalyzed oxidation of  l- and  d-lactic acids. This study provided an important support for the production of cellulosic  l-lactic acid with high chiral purity.

Effects of chemical factors on the infectivity of Decapod iridescent virus 1 (DIV1).

The effects of chemical factors on the infectivity of DIV1 have not been fully accessed yet. In order to investigate the stability of DIV1 to strong brine, pH, and other chemical conditions, we conducted a bioassay using clinically healthy Penaeus vannamei individuals. DIV1 inoculum was exposed to various chemical conditions, and the infectivity of DIV1 was determined through intramuscular injection. The results showed that DIV1 lost its infectivity when exposed to strong brine, specifically in a 3 mol/L NaCl solution for a duration of 1 h. Moreover, DIV1 was found to be inactivated within 1 h when subjected to pH levels below 3.1 or above 9.6. Additionally, both Triton X-100 and 1 % formaldehyde demonstrated the ability to inactivate DIV1. These results provide valuable insights into the tolerance of DIV1 towards certain chemical factors, serving as a reference for the establishment of biosecurity measures against DIV1.

Smart Carbon Nanotubes with Laser-Controlled Behavior in Gene Delivery and Therapy through a Non-Digestive Trafficking Pathway.

Near-infrared (NIR) laser-controlled gene delivery presents some benefits in gene therapy, inducing enhanced gene transfection efficiency. In this study, a "photothermal transfection" agent is obtained by wrapping poly(ethylenimine)-cholesterol derivatives (PEI-Chol) around single-walled carbon nanotubes (SWNTs). The PEI-Chol modified SWNTs (PCS) are effective in compressing DNA molecules and protecting them from DNaseI degradation. Compared to the complexes formed by PEI with DNA (PEI/DNA), complexes of PCS and DNA that are formed (PCS/DNA) exhibit a little lower toxicity to HEK293 and HeLa cells under the same PEI molecule weight and weight ratios. Notably, caveolae-mediated cellular uptake of PCS/DNA occurs, which results in a safer intracellular transport of the gene due to the decreased lysosomal degradation in comparison with that of PEI/DNA whose internalization mainly depends on clathrin rather than caveolae. Furthermore, unlike PEI/DNA, PCS/DNA exhibits a photothermal conversion ability, which promotes DNA release from PCS under NIR laser irradiation. The NIR laser-mediated photothermal transfection of PCS10K /plasmid TP53 (pTP53) results in more apoptosis and necrosis of HeLa cells in vitro than other groups, and achieves a higher tumor-growth inhibition in vivo than naked pTP53, PEI25K /pTP53, and PCS10K /pTP53 alone. The enhanced transfection efficiency of PCS/DNA can be attributed to more efficient DNA internalization into the tumor cells, promotes detachment of DNA from PCS under the mediation of NIR laser and higher DNA stability in the cells due to caveolae-mediated cellular uptake of the complexes.

Extremely Effective Chemoradiotherapy by Inducing Immunogenic Cell Death and Radio-Triggered Drug Release under Hypoxia Alleviation.

Local hypoxia in solid malignancies often results in resistance to radiotherapy (RT) and chemotherapy (CT), which may be one of the main reasons for their failure in clinical application. Especially, oxygen is an essential element for enhancing DNA damage caused by ionizing radiation in radiotherapy. Here, two biomimetic oxygen delivery systems were designed by encapsulating hemoglobin (Hb) alone into a liposome (Hb-Lipo) or co-encapsulating Hb and doxorubicin (DOX) into a liposome (DOX-Hb-Lipo). Our data indicated that both Hb-Lipo and DOX-Hb-Lipo could effectively alleviate hypoxia in tumors. We demonstrated that RT plus tumor-targeting delivery of oxygen mediated by Hb-Lipo could significantly overcome the tolerance of hypoxic cancer cells to RT, showing significantly enhanced cancer-cell killing and tumor growth inhibition ability, mainly attributing to hypoxia alleviation and increased reactive oxygen species production under RT in cancer cells. Furthermore, a melanoma model that was quite insensitive to both RT and CT was used to test the efficacy of chemoradiotherapy combined with hypoxia alleviation. RT plus Hb-Lipo only caused a limited increase in antitumor activity. However, extremely strong tumor inhibition could be obtained by RT combined with DOX-Hb-Lipo-mediated CT, attributed to radio-triggered DOX release and enhanced immunogenic cell death induced by RT under an oxygen supplement. Our study provided a valuable reference for overcoming hypoxia-induced radioresistance and a useful therapeutic strategy for cancers that are extremely insensitive to chemo- or radiotherapy.

Temperature-controlled, phase-transition ultrasound imaging-guided photothermal-chemotherapy triggered by NIR light.

Recently, nano-sized ultrasound contrast agents encapsulating drugs for cancer diagnosis and therapy have attracted much attention. However, the ultrasound signal of these agents is too weak to obtain an ideal ultrasound imaging effect. Furthermore, conventional ultrasound contrast agents with strong echo signal are not suitable for drug delivery against cancer because of their large size. To circumvent this problem, phase-transition ultrasound contrast agents are believed to be an excellent choice. Methods: Liposomes co-encapsulating doxorubicin (DOX), hollow gold nanospheres (HAuNS), and perfluorocarbon (PFC) were synthesized by film dispersion method. The morphology, particle size, and stability of these liposomes (DHPL) were investigated. The photothermal effect, drug release, particle size change, cytotoxicity, and ultrasound imaging were studied by using the near infrared (NIR) light. Furthermore, tumor accumulation of DHPL was observed by in vivo fluorescence imaging and the antitumor effect was verified in a 4T1 tumor model. Results: The nanosystem displayed a homogeneous size distribution (~200 nm) and an efficient light-to-heat conversion effect under 808 nm NIR laser irradiation. The nanometer size enabled considerable accumulation of DHPL in the tumor sites. The localized hyperthermia resulting from the photothermal effect of HAuNS could trigger the size transformation of DHPL followed by significant DOX release. Due to the gasification of PFC, a remarkably enhanced ultrasound signal was detected. DHPL also exhibited a prominent photothermally reinforced chemotherapeutic effect under the control of NIR light both in vitro and in vivo. Importantly, no systemic toxicity was observed by DHPL treatment. Conclusion: In this study, we fabricated multi-functional perfluorocarbon liposomes for ultrasound imaging-guided photothermal chemotherapy which have the potential to serve as a prospective cancer treatment approach.

Synchronous delivery of oxygen and photosensitizer for alleviation of hypoxia tumor microenvironment and dramatically enhanced photodynamic therapy.

Photosensitizer, proper laser irradiation, and oxygen are essential components for effective photodynamic therapy (PDT) in clinical cancer therapy. However, native hypoxic tumoral microenvironment is a major barrier hindering photodynamic reactions in vivo. Thus, we have prepared biocompatible liposomes by loading complexes of oxygen-carrier (hemoglobin, Hb) and photosensitizer (indocyanine green, ICG) for enhanced PDT against hypoxic tumor. Ideal oxygen donor Hb, which is an oxygen-carried protein in red blood cells, makes such liposome which provide stable oxygen supply. ICG, as a photosensitizer, could transfer energy from lasers to oxygen to generate cytotoxic reactive oxygen species (ROS) for treatment. The liposomes loading ICG and Hb (LIH) exhibited efficient tumor homing upon intravenous injection. As revealed by T2-weighted magnetic resonance imaging and immunohistochemical analysis, the intratumoral hypoxia was greatly alleviated, and the level of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in tumor was obviously down-regulated. A weak PDT efficiency was found in cells incubated in simulated hypoxia condition in vitro, while PDT effect was dramatically enhanced in LIH treated hypoxia cells under near-infrared (NIR) laser, which was mainly attributed to massive generation of ROS with sufficient oxygen supply. ROS trigger oxidative damage of tumors and induce complete suppression of tumor growth and 100% survival rate of mice, which were also in good health condition. Our work highlights a liposome-based nanomedicine that could effectively deliver oxygen to tumor and alleviate tumor hypoxia state, inducing greatly improved efficacy compared to conventional cancer PDT and demonstrates the promise of modulating unfavorable tumor microenvironment with nanotechnology to overcome limitations of cancer therapies.

Preparation of artificial red cell and its application on alleviation of tumor hypoxia.

Hemoglobin-based oxygen carriers were developed as an alternative for blood transfusion. However, the research progress for their further clinic applications was slow in recent several years. Hypoxia is found in most solid tumors, which is responsible for the tumor formation, increased metastasis, drug resistance during therapeutic process as well as poor patient survival. In this work, novel hemoglobin (Hb) loaded nanoliposomes, as artificial red cells for oxygen delivery, were optimized by screening various types of phospholipids and analyzing different mole ratio of phospholipid to cholesterol. The nanoliposomes presented a high encapsulating efficiency to hemoglobin and also significantly enhanced its stability. The obtained hemoglobin loaded nanoliposome (HLL) could be lyophilized for long term storage. HLL did not cause significant cell death in the concentration range of 0-100µg equivalent Hb/mL under normoxia and hypoxia incubation conditions, suggesting the low cytotoxicity and high biocompatibility of HLL. Importantly, HLL could efficiently accumulate into subcutaneous and deep orthotopic tumors, inducing a significant decrease of hypoxia-inducible factors 1α subunits (HIF-1α) in the tumors and remarkably reduced expression of vascular endothelial growth factor (VEGF). The study of acute and chronic toxicity indicated that HLL did not induce obvious damage to main organs of mice after intravenous injections with total Hb dose of 120mg/kg. We presented a promising method for relieving the hypoxia degree in solid tumors and down-regulating HIF-1α protein by directly delivering oxygen into tumors, which will be very helpful for subsequent cancer therapy.