Pure PBS was used as a reference solution and samples scanned in the wavelength range of 200 nm to 800 nm for the confirmation of response to light. degeneration (AMD) and diabetic retinopathy. AZP nanospheres were Rabbit polyclonal to VPS26 prepared via coacervation technique, dispersed in HA hydrogel and characterised via infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Size and morphology were studied via scanning electron microscopy (SEM) and dynamic light scattering (DLS), UV spectroscopy for photo-responsiveness. Rheological properties and injectability were investigated, as well as cytotoxicity effect on HRPE cell lines. Particle size obtained was 200 nm and photo-responsiveness to UV = 365 nm by decreasing particle diameter to 94 nm was confirmed by DLS. Encapsulation efficiency of the optimised nanospheres was 85% and IgG was released over 32 days Hoechst 33258 analog 2 up to 60%. Injectability of HA-NSP was confirmed with maximum force 10 N required and shear-thinning behaviour observed in rheology studies. In vitro cell cytotoxicity effect of both NSPs and HA-NSP showed non-cytotoxicity with relative cell viability of 80%. A biocompatible, biodegradable injectable photo-responsive nanosystem for sustained release of macromolecular IgG was successfully developed. to when irradiated with UV light of a certain wavelength. Light is usually remotely Hoechst 33258 analog 2 controlled and that renders it non-invasive; it is also independent of chemical environmental changes experienced at different stages of disease progression and increases prospects of targeted delivery [18,19]. Hydrogel based drug delivery systems are best suitable for the purpose of flexibility and injectability. Directly incorporating drugs into hydrogels results in a shorter drug release time as a consequence of fast diffusion caused by high water content in the hydrogel [20]. Nanocarriers improve passage through tissue and control drug release into the target tissue. However, administration of drug loaded nanocarriers as solid implantable delivery systems requires invasive surgical procedures and injection is not applicable due to aggregation Hoechst 33258 analog 2 and sedimentation which leads to high residue in the syringe after injection and insufficient therapeutic levels at the target site. Injectable hydrogels can overcome these drawbacks as they possess the advantage of minimal invasive administration and reach for asymmetrical target sites [21]. Drug loaded solid nanoparticles can be dispersed in an injectable hydrogel for homogeneity, ease of administration and optimal therapeutic concentrations at target tissue to improve patient adherence. In addition, hydrogel-nanoparticle combinations provide diverse synergistic properties superior to their individual composites [22,23]. The aim of this study was to develop an injectable photo-responsive delivery system for sustained release of macromolecules. In this study, zein was blended with DHAB to formulate photo-responsive nanospheres encapsulated with a monoclonal antibody Immunoglobulin G (IgG) as a model protein via coacervation method. A nanosystem comprising of photo-responsive IgG loaded azoprolamin (AZP) nanospheres coated with gelatin and dispersed in genipin (GP) crosslinked hyaluronic acid hydrogel (HA) were successfully prepared and characterised through Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). To our knowledge, this is the first report investigating photo-responsive AZP nanospheres dispersed in HA hydrogel for sustained delivery of macromolecules. 2. Results and Discussion IgG loaded photo-responsive AZP nanospheres were prepared by coacervation method, freeze-dried and homogenously dispersed in HA hydrogel to obtain an injectable nanosystem. Genipin was used to enhance the viscosity of the HA hydrogel in order to avoid sedimentation of the dispersed nanospheres. Genipin reacts with primary amino groups of proteins and amino acids to produce blue pigments [24]. This pigment was observed in the HA hydrogels modified with genipin. The colour variation is shown in Physique 1 where a and c are pure HA hydrogels with a clear colour, b, the HA-GP hydrogel showing a light blue colour and d, the obtained HA-NSP nanosystem displaying the dispersion of nanospheres in the hydrogel. The darker pigment in HA-NSP may be attributed to the presence of amino groups in the composition of AZP nanospheres as well as their brown colour. Open in a separate window Physique 1 Images of the formulations (a) pure HA hydrogel, (b) HA-GP hydrogel, (c) pure HA hydrogel and (d).
