Spatioselective Modification of Bicompartmental Polymer Particles and Fibers via Huisgen 1,3-Dipolar Cycloaddition

Precise nano- and microscale control of the architecture of biodegradable biomaterials is desirable for several biotechnological applications such as drug delivery, diagnostics, and medical imaging. Herein, we combine electrohydrodynamic co-jetting and highly specific surface modification (via Huisgen 1,3-dipolar cycloaddition) to prepare particles and fibers with spatioselective surface modification. We first prepared biphasic particles and fibers from commercial poly(lactide- co -glycolide) copolymers via electrohydrodynamic co-jetting of two organic solutions loaded with fluorescent macromolecules and acetylene-modified PLGA derivatives. (i) Spatially controlled reaction of poly[lactide- co -(propargyl glycolide)] with O -(2-aminoethyl)- O ′-(2-azidoethyl)heptaethylene glycol and (ii) subsequent conversion of the newly introduced amino groups with fluorescence probes resulted in particles and fibers with surface modification of one hemisphere only.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/61239/1/1655_ftp.pd

Punica granatum (Pomegranate) juice provides an HIV-1 entry inhibitor and candidate topical microbicide

BACKGROUND: For ≈ 24 years the AIDS pandemic has claimed ≈ 30 million lives, causing ≈ 14,000 new HIV-1 infections daily worldwide in 2003. About 80% of infections occur by heterosexual transmission. In the absence of vaccines, topical microbicides, expected to block virus transmission, offer hope for controlling the pandemic. Antiretroviral chemotherapeutics have decreased AIDS mortality in industrialized countries, but only minimally in developing countries. To prevent an analogous dichotomy, microbicides should be: acceptable; accessible; affordable; and accelerative in transition from development to marketing. Already marketed pharmaceutical excipients or foods, with established safety records and adequate anti-HIV-1 activity, may provide this option. METHODS: Fruit juices were screened for inhibitory activity against HIV-1 IIIB using CD4 and CXCR4 as cell receptors. The best juice was tested for inhibition of: (1) infection by HIV-1 BaL, utilizing CCR5 as the cellular coreceptor; and (2) binding of gp120 IIIB and gp120 BaL, respectively, to CXCR4 and CCR5. To remove most colored juice components, the adsorption of the effective ingredient(s) to dispersible excipients and other foods was investigated. A selected complex was assayed for inhibition of infection by primary HIV-1 isolates. RESULTS: HIV-1 entry inhibitors from pomegranate juice adsorb onto corn starch. The resulting complex blocks virus binding to CD4 and CXCR4/CCR5 and inhibits infection by primary virus clades A to G and group O. CONCLUSION: These results suggest the possibility of producing an anti-HIV-1 microbicide from inexpensive, widely available sources, whose safety has been established throughout centuries, provided that its quality is adequately standardized and monitored

Can host reaction animal models be used to predict and modulate skin regeneration?

The study of host reactions in the biomedical and tissue engineering (TE) fields is a key issue but somehow set aside where TE constructs are concerned. Every day new biomaterials and TE constructs are being developed and presented to the scientific community. The combination of cells and biomolecules with scaffolding materials, as TE constructs, make the isolation and the understanding of the effect of each one those elements over the overall host reaction difficult. Eventually, all variables influence the host reaction and the performance of the constructs. For this reason, current assessment of the in vivo performance of TE constructs follows individual approaches, using specific animal models to independently provide insights regarding the contribution of the biomaterials/scaffolds towards the host reaction, and of all the constructs regarding their functionality. Skin wound healing progress into tissue regeneration or repair is highly dependent on the specificities of the inflammatory stage, as demonstrated by comparison between fetal and adult mechanisms. Thus, it would be expected that insights acquired from host tissue reaction evaluation to biomaterials/scaffolds would be explored to predict healing progression and improve the functionality of skin TE constructs. The rational of this review is to make a comprehensive analysis of to what extent the knowledge obtained from the evaluation of in vivo host reactions to implantable biomaterials/scaffolds has been used in the design of skin TE strategies, by promoting tissue regeneration rather than repair.T.C.S. acknowledges Grant No. RL3-TECT-NORTE-01-0124-FEDER-000020, co-financed by the North Portugal Regional Operational Programme (ON.2-O Novo Norte), under the National Strategic Reference Framework, through the European Regional Development Fund

Testing natural biomaterials in animal models

Animal models have been extensively developed in the last decades in biomedical field. Their use has shown particular relevance in fields such as cell biology, genetics, anatomy and development, biochemistry, infection and immunity, cancer research, drugs and vaccine development, tissue engineering and regenerative medicine. The induced host tissue trauma and the inflammatory process resulting from the implantation of a medical device are of utmost importance for a successful outcome. Features of a chronic inflammation are usually attributed to the host response towards the implant, while an early acute inflammatory response is mainly endorsed by the implantation procedure. Animal testing comprises a midway step between in vitro studies and human clinical trials, which precede real clinical application. As every animal model has its advantages and disadvantages, a comprehensive analysis of each available species needs to be conducted when planning an animal study.(undefined)info:eu-repo/semantics/publishedVersio