Biodegradable mesostructured polymer membranes

Implantable optical fibers for immunotherapeutics delivery and tumor impedance measurement

Immune checkpoint blockade antibodies have promising clinical applications but suffer from disadvantages such as severe toxicities and moderate patient-response rates. None of the current delivery strategies, including local administration aiming to avoid systemic toxicities, can sustainably supply drugs over the course of weeks; adjustment of drug dose, either to lower systemic toxicities or to augment therapeutic response, is not possible. Herein, we develop an implantable miniaturized device using electrode-embedded optical fibers with both local delivery and measurement capabilities over the course of a few weeks. The combination of local immune checkpoint blockade antibodies delivery via this device with photodynamic therapy elicits a sustained anti-tumor immunity in multiple tumor models. Our device uses tumor impedance measurement for timely presentation of treatment outcomes, and allows modifications to the delivered drugs and their concentrations, rendering this device potentially useful for on-demand delivery of potent immunotherapeutics without exacerbating toxicities.

Effects of Liposomes Contained in Thermosensitive Hydrogels as Biomaterials Useful in Neural Tissue Engineering

Advances in the generation of suitable thermosensitive hydrogels for the delivery of cells in neural tissue engineering demonstrate a delicate relationship between physical properties and capabilities to promote cell proliferation and differentiation. To improve the properties of these materials, it is possible to add liposomes for the controlled release of bioactive elements, which in turn can affect the physical and biological properties of the hydrogels. In the present investigation, different hydrogels based on Pluronic F127 have been formulated with the incorporation of chitosan and two types of liposomes of two different sizes. The rheological and thermal properties and their relation with the neurite proliferation and growth of the PC12 cell line were evaluated. Our results show that the incorporation of liposomes modifies the properties of the hydrogels dependent on the concentration of chitosan and the lipid type in the liposomes, which directly affect the capabilities of the hydrogels to promote the viability and differentiation of PC12 cells.

Controlled drug release and hydrolysis mechanism of polymer-magnetic nanoparticle composite

Uniform and multifunctional poly(lactic acid) (PLA)-nanoparticle composite has enormous potential for applications in biomedical and materials science. A detailed understanding of the surface and interface chemistry of these composites is essential to design such materials with optimized function. Herein, we designed and investigated a simple PLA-magnetic nanoparticle composite system to elucidate the impact of nanoparticles on the degradation of polymer-nanoparticle composites. In order to have an in-depth understanding of the mechanisms of hydrolysis in PLA-nanoparticle composites, degradation processes were monitored by several surface sensitive techniques, including scanning electron microscopy, contact angle goniometry, atomic force microscopy, and sum frequency generation spectroscopy. As a second-order nonlinear optical technique, SFG spectroscopy was introduced to directly probe in situ chemical nature at the PLA-magnetic nanoparticle composite/aqueous interface, which allowed for the delineation of molecular mechanisms of various hydrolysis processes for degradation at the molecular level. The best PLA-NP material, with a concentration of 20% MNP in the composite, was found to enhance the drug release rate greater than 200 times while maintaining excellent controlled drug release characteristics. It was also found that during hydrolysis, various crystalline-like PLA domains on the surfaces of PLA-nanoparticle composites influenced various hydrolysis behaviors of PLA. Results from this study provide new insight into the design of nanomaterials with controlled degradation and drug release properties, and the underlined molecular mechanisms. The methodology developed in this study to characterize the polymer-nanoparticle composites is general and widely applicable.