NIR-II-activated biocompatible hollow nanocarbons for cancer photothermal therapy.

Photothermal therapy has attracted extensive attentions in cancer treatment due to its precise spatial-temporal controllability, minimal invasiveness, and negligible side effects. However, two major deficiencies, unsatisfactory heat conversion efficiency and limited tissue penetration depth, hugely impeded its clinical application. In this work, hollow carbon nanosphere modified with polyethylene glycol-graft-polyethylenimine (HPP) was elaborately synthesized. The synthesized HPP owns outstanding physical properties as a photothermal agent, such as uniform core-shell structure, good biocompatibility and excellent heat conversion efficiency. Upon NIR-II laser irradiation, the intracellular HPP shows excellent photothermal activity towards cancer cell killing. In addition, depending on the large internal cavity of HPP, the extended biomedical application as drug carrier was also demonstrated. In general, the synthesized HPP holds a great potential in NIR-II laser-activated cancer photothermal therapy.

Immunogenicity of the capsid precursor and a nine-amino-acid site-directed mutant of the 3C protease of foot-and-mouth disease virus coexpressed by a recombinant goatpox virus.

The myristoylated capsid precursor mP1-2A of foot-and-mouth disease virus (FMDV), when expressed in mammalian cells and processed by the FMDV 3C protease, can self-assemble into virus-like particles (VLPs). In the present study, nine amino acids of the 3C protease were replaced by site-directed mutagenesis to create a mutant 3C protease, 9m3C. To coexpress mP1-2A and 9m3C and test the resulting proteolytic processing and VLP assembly, two recombinant goatpox viruses (rGTPVs) were constructed by the insertion of two coding regions, one for mP1-2A and the other for either 9m3C (rGTPV-mP1-2A-9m3C) or Theileria protective antigen (TPA) as a control (rGTPV-mP1-2A-TPA). The two exogenous genes were inserted into an intergenic region between loci gp_24 and gp_24.5 of the rGTPV genome. Western blotting of cells infected with rGTPV-mP1-2A-9m3C showed that proteins VP0, VP1, and VP3 from the mP1-2A processed by the 9m3C protease could be detected by polyclonal FMDV sera. As observed by electron microscopy, the infected cells produced VLPs with a diameter of about 25 ± 2 nm. Titers of neutralizing antibody against FMDV were significantly higher in mice inoculated with rGTPV-mP1-2A-9m3C, which expresses the 9m3C protease together with mP1-2A, than mice inoculated with the control rGTPV-mP1-2A-TPA, which does not express the protease. An ovine immunization test determined that sheep inoculated intramuscularly with rGTPV-mP1-2A-9m3C produced FMDV-specific neutralizing antibody, but its titers did not meet the requirement of the World Organization for Animal Health. The result indicates that further modifications of rGTPV-mP1-2A-9m3C are necessary to produce an effective vaccine.

[The hydrophilicity and cell affinity of polylactic acid containg bionic function group of phosphorylcholine].

A series of novel biodegradable and bionic functional polymers, PLLA-PC-PLLA, were synthesized using L-lactide ring-opening polymerization by L-a-Glycerophosphorylcholine (PC) from nature source. The hydrophilicity of the polymers was investigated. The results made known that, as PC group was brought into the backbone of PLLA, PLLA-PC-PLLA gained much better hydrophilicity than did PLLA, and polar phosphatidylcholines probably transferred to the sample surface in aqueous environment. The relative growth ratios of ECV304 cells to the lixivium of all PLLA-PC-PLLA were higher than 84% in 5 d culture. The cells adhesion of ECV304 on the films of PLLA-PC-PLLA lagged as compared to that on PLLA, but they could proliferate and cover the films in total. The difference between PLLA-PC-PLLA and PLLA was due to the existence of PC group. Thus, PLLA-PC-PLLA, the same as PLLA, are not cytotoxic, and ECV304 can attach and proliferate on them. PLLA-PC-PLLA have potential applications in the fields of tissue engineering and drug delivery system.

[Self-assembled monolayers as model systems to study the relation between biocompatibity and surface chemistry of biomaterials].

The surface properties of biomaterials are essentially important to their biocompatibility. The complexity of surface composition and structure of biomaterials bring out the problem that it is difficult to make fully clear how the surface chemical properties and the structures of biomaterials control the biological reactions between the surfaces and proteins and/or cells. The structure of self-assembled monolayers (SAMs) is well established and SAMs have the characteristics of which a variety of functional groups and molecules can be introduced, either before or after the monolayer is formed, and diversified spectroscopy monitoring can be used to characterize SAMs and changes after their interactions with proteins or cells. Thus, SAMs are suitable model substrates for the study of the relationship between the surface chemical properties and biocompatibility of biomaterials. This paper reviews the researches on SAMs as models to study the absorption of proteins, cell adhesion and proliferation on materials, and the influences of both surface chemical functional groups and motion of molecular chains on hemocompatibility of biomaterials.

Biodegradable heparin-loaded microspheres: carrier molecular composition and microsphere structure.

Microspheres of amphiphilic triblock polymers PLLA-PEG-PLLA were investigated as carriers for heparin delivery. Two series of PLLA-PEG-PLLA triblock were synthesized and prepared into microspheres with heparin loaded. The microspheres were hollow and the surface morphology varied from smooth to porous. The pore size increased with increasing PEG content. The microsphere size distribution showed that higher PEG content increased the average microsphere size. The release rate of heparin was closely related to the surface morphology of the microspheres. DSC spectra showed that both cold crystalline temperature (Tc) and crystalline melting temperature (Tm) of heparin-loaded microspheres were related to the copolymer composition and the Tc was lower than those of corresponding pure microspheres. [IMAGES: SEE TEXT]

Behavior of endothelial cells regulated by a dynamically changed microenvironment of biodegradable PLLA-PC.

The influence of PLLA-PC membranes on the behavior of vascular ECs is studied. It was found that the membranes were not cytotoxic. The cell adhesion and spread on PLLA-PC 30/1 were initially depressed. After 1 d, however, cells attached and spread on the copolymer, and proliferated beyond 2 d. To elucidate the mechanism of this behavior, the surface morphology and the degradation products of the PLLA/PC 30/1 membrane during the culture period were tested, and Fg adsorption to the membranes was examined. It is concluded that the behavior of ECs can be regulated by a dynamically changed microenvironment of the PLLA-PC membrane. PLLA-PC copolymers might therefore serve as a novel material for tissue engineering.