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Polyelectrolyte complexes (PECs) are attractive materials for drug delivery application as they offer simple preparations and high drug-loading efficiency. In this study, a novel method for preparing polyelectrolyte complex nanoparticles using a simple mixing method of chitosan and poly-2-acrylamido-2-methylpropane sulfonic acid (PAMPS) solutions is presented. The effect of chitosan concentrations was examined by fixing the PAMPS concentration at 0.01 %w/v, while chitosan concentrations were varied from 0.01 to 0.05 %w/v. Based on dynamic light scattering (DLS) and zeta sizer results, increasing the chitosan concentration led to increased average PEC particle sizes with broader particle distributions from 249.1 (polydispersity index/PDI 0.13) to 318.2 nm (PDI 0.19) and changed the particle surface charges from -5.85±0.34 to 11.95±0.84 mV. The addition of glutaraldehyde (GA) followed by dialysis eliminated sodium chloride (NaCl) and produced spherical PEC nanoparticles, confirmed via scanning electron microscopy (SEM) results. Among those samples, PECs with a chitosan concentration of 0.01 %w/v are the most promising drug carrier materials due to their negative surface charges, which promote prolonged circulation time in the bloodstream.

There are many DDS (Drug Delivery System) methods that can be used in this decade. The DDS method with nanotechnology is also increasingly in demand because it can be a controlled DDS (CDDS). One of the nanomaterials that can be useful for this purpose is Mesporous Silica Nanoparticle or MSN. This article provides a review that discusses how MSN can deliver drugs, the synthesis method and its level of ability in DDS. MSN showed that its ability to deliver various types of drugs including Ibuprofen, Doxorubicin and general antibiotics. The results of the synthesis can use solution based and EISA where the release properties in DDS are quite effective. This shows that MSN is good for the use of CDDS.

Zinc oxide (ZnO) has been considered as one of the potential materials in solar cell applications, owing to its relatively high conductivity, electron mobility, stability against photo-corrosion and availability at low-cost. Different structures of ZnO materials have been engineered at the nanoscale, and then applied on the conducting substrate as a photoanode. On the other hand, the ZnO nanomaterials directly grown on the substrate have been attractive due to their unique electron pathways, which suppress the influence of surface states typically found in the former case. Herein, we review the recent progress of ZnO nanostructured materials in emerging solar cell applications, such as sensitized and heterojunction architectures, including those embedded with promising perovskite materials. The remarkable advancement in each solar cell architecture is highlighted towards achieving high power conversion efficiency and operational stability. We also discuss the foremost bottleneck for further improvements and the future outlook for large-scale practical applications.

Polyelectrolyte complexes (PECs) is one of attractive materials for biomedical application because it can be prepared by simple mixing of oppositely charge polymers in aqueous solution. Electrostatic interaction between positively and negatively charged polymers play an important role on PEC stability. However, electrostatic interaction is not permanent crosslink and depend on their environment condition, such as salinity. In this research, PECs was prepared by simple mixing method between chitosan (positively charge polymers) solution and poly-2-acrylamido-2-methylprophane sulfonic acid (PAMPS; negatively charge polymers) solution. Stability of PECs in dilute sodium chloride solution was studied by comparing bare PECs sample with cross linked PECs sample after incubated for 2 weeks at room temperature. Visual observation suggested that particles size of bare PECs after 2 weeks is bigger than crosslinked-PECs. Further characterization using dynamic light scattering (DLS) method showed that particles size of bare PECs (759.9 nm) is bigger than crosslinked-PECs (166.0 nm). Morphological observation using scanning electron microscopy (SEM) method revealed that bare PECs particles were fused and formed bigger particles after 2 weeks, while particles size of crosslinked-PECs were stable enough after 2 weeks.