A MODEL FOR THE RELEASE BEHAVIOR OF DRUGS FROM HYDROGEL NANOPARTICLE

A model to correlate and predict the release behavior of drugs from hydrogel nanoparticles is presented in this paper. The nanoparticle is considered as a combination of a shell of an elastic semipermeable membrane and a core of a fluid phase （After swelling equilibrium）. The fluid core consists of network building materials and other components that are able to partition in hydrogel nanoparticle phase and surrounding coexisting liquid phase, and is enveloped by the membrane shell. The excess Gibbs energies of the hydrogel nanoparticle phase and the surrounding coexisting fluid phase are expressed e.g. using UNIQUAC equation with ＂free-volume＂ contribution for non-ionic solution and VERS-model for ionic one. The elastic properties of polymer network could be described, for example, by the ＂phanWm network＂ theory.

A Novel Urine Method for the Diagnosis of Active Tuberculosis by Immunoassay for the Detection of ESAT-6 Using Hydrogel Nanoparticles in HIV Patients

Background: In patients with HIV, conventional tests are of low sensitivity;therefore, a new diagnostic test with hydrogel nanoparticles with reactive blue dye is proposed, which allows the capture, conservation and concentration of ESAT-6 in urine. NIPAs are copolymers that capture low molecular weight proteins and protect against enzymatic degradation. Using an immunoassay, it is possible to detect and quantify ESAT-6 present in urine as a possible marker of active TB. Design/Methods: Study in Lima, Peru, HIV+ participants, ≥18 years with and without tuberculosis (TB). Smear microscopy, culture in solid medium and urine immunoassay were performed. The reference was the diagnosis of TB by radiological or clinical microbiological criteria (indication for TB treatment). There were 2 preanalytical processes: untreated and treated urine (centrifuged, heated), then incubation with NIPAm. After washing, elution, sonication, heat and centrifugation, the final eluate was obtained. This was placed on nitrocellulose membranes, which by means of fixation and incubation processes with anti-ESAT-6 and anti-IgG antibodies, revelation with C-DiGit® Blot Scanner and FluorChem R FR0001. Calibration curves were included in the membranes, density was measured using Image J software. ROC curves, sensitivity and specificity were obtained. Results: The result by groups was HIV+ patient: ROC: 0.75, cut-off point ≥24.06 ng/ml, sensitivity 76.32%, specificity 68.89%, patients ≤200 cells CD4 mm3/ml, ROC: 0.78, cutoff point ≥26.20 ng/ml, sensitivity 75.86%, specificity 71.88%, patients >200 CD4 mm3 cells/ml, ROC: 0.73, cutoff point ≥24.6 CD4 mm3/ml, sensitivity 73.68%, specificity 73.68%. Conclusions: The ESAT-6 detection assay using NIPAm was effective, with higher rates in patients with ≤200 CD4 cells/mm3, the test being more sensitive than smear and culture, but less specific.

Porous tantalum-composited gelatin nanoparticles hydrogel integrated with mesenchymal stem cell-derived endothelial cells to construct vascularized tissue in vivo

The ideal scaffold material of angiogenesis should have mechanical strength and provide appropriate physiological microporous structures to mimic the extracellular matrix environment.In this study,we constructed an integrated three-dimensional scaffold material using porous tantalum(pTa),gelatin nanoparticles(GNPs)hydrogel,and seeded with bone marrow mesenchymal stem cells(BMSCs)-derived endothelial cells(ECs)for vascular tissue engineering.The characteristics and biocompatibility of pTa and GNPs hydrogel were evaluated by mechanical testing,scanning electron microscopy,cell counting kit,and live-cell assay.The BMSCs-derived ECs were identified by flow cytometry and angiogenesis assay.BMSCs-derived ECs were seeded on the pTa-GNPs hydrogel scaffold and implanted subcutaneously in nude mice.Four weeks after the operation,the scaffold material was evaluated by histomorphology.The superior biocompatible ability of pTa-GNPs hydrogel scaffold was observed.Our in vivo results suggested that 28 days after implantation,the formation of the stable capillary-like network in scaffold material could be promoted significantly.The novel,integrated pTa-GNPs hydrogel scaffold is biocompatible with the host,and exhibits biomechanical and angiogenic properties.Moreover,combined with BMSCs-derived ECs,it could construct vascular engineered tissue in vivo.This study may provide a basis for applying pTa in bone regeneration and autologous BMSCs in tissue-engineered vascular grafts.

Concentration and Preservation of Very Low Abundance Biomarkers in Urine, such as Human Growth Hormone (hGH), by Cibacron Blue F3G-A Loaded Hydrogel Particles

Urine is a potential source of diagnostic biomarkers for detection of diseases,and is a very attractive means of non-invasive biospecimen collection.Nonetheless,proteomic measurement in urine is very challenging because diagnostic biomarkers exist in very low concentration(usually below the sensitivity of common immunoassays)and may be subject to rapid degradation.Hydrogel nanoparticles functionalized with Cibacron Blue F3G-A(CB)have been applied to address these challenges for urine biomarker measurement.We chose one of the most difficult low abundance,but medically relevant,hormones in the urine:human growth hormone(hGH).The normal range of hGH in serum is 1 to 10 ng/mL but the urine concentration is suspected to be a thousand times less,well below the detection limit(50 pg/mL)of sensitive clinical hGH immunoassays.We demonstrate that CB particles can capture,preserve and concentrate hGH in urine at physiological salt and urea concentrations,so that hGH can be measured in the linear range of a clinical immunometric assay.Recombinant and cadaveric hGH were captured from synthetic and human urine,concentrated and measured with an Immulite chemiluminescent immunoassay.Values of hGH less than 0.05 ng/mL(the Immulite detection limit)were concentrated to 2 ng/mL,with a urine volume of 1 mL.Dose response studies using 10 mL of urine demonstrated that the concentration of hGH in the particle eluate was linearly dependent on the concentration of hGH in the starting solution,and that all hGH was removed from solution.Thus if the starting urine volume is 100 mL,the detection limit will be 0.1 pg/mL.Urine from a healthy donor whose serum hGH concentration was 1.34 ng/mL was studied in order detect endogenous hGH.Starting from a volume of 33 mL,the particle eluate had an hGH concentration of 58 pg/mL,giving an estimated initial concentration of hGH in urine of 0.175 pg/mL.The nanotechnology described here appears to have the desired precision,accuracy and sensitivity to support large scale clinical studies of urine hGH levels.

Tough superabsorbent poly(acrylic acid) nanocomposite physical hydrogels fabricated by a dually cross-linked single network strategy

In this work, we report a facile method for the preparation of tough and highly stretchable physical hydrogels by dual cross-linking composed of vinyl-hybrid silica nanoparticles（VSNPs） as multivalent covalent cross-linking and hydrogen bonding as physical cross-linking. Poly（acrylic acid） nanocomposite physical hydrogels（NCP gels） are obtained without adding any organic chemical cross-linkers. When the content of VSNPs is 0.7 wt%（relative to the monomer）, the NCP gels exhibit good mechanical properties（fracture strength = 370 k Pa, elongation at break = 2200%） and a high swelling capacity in both deionized water（2300 g/g） and saline（220 g/g）. Meanwhile, the NCP gels have good recovery ability.